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Sample records for adventist edge school

  1. A Descriptive Case Study of the Perceptions and Use of Adventist Edge: An Initiative Developed in Response to the North American Division of Seventh-Day Adventists' Document, "Journey to Excellence"

    ERIC Educational Resources Information Center

    Forbes, Pamela C.

    2011-01-01

    Problem. The Southern Union started the Adventist EDGE initiative as an action plan in response to the North American Division's document, "Journey to Excellence." The Adventist EDGE became a comprehensive educational reform initiative. However, there were different ideas on how the innovation should look when in action in the schools, and these…

  2. CognitiveGenesis (CG): Assessing Academic Achievement and Cognitive Ability in Adventist Schools

    ERIC Educational Resources Information Center

    Thayer, Jerome; Kido, Elissa

    2012-01-01

    CognitiveGenesis collected achievement and ability test data from 2006-2009 for all students in Seventh-day Adventist schools in North America. Students were above average in achievement compared to national norms and achieved above that predicted by their ability scores. The more years students attended Adventist schools, the higher they…

  3. An Analysis of Spiritual Factors on Academic Achievement in Seventh-Day Adventist Schools

    ERIC Educational Resources Information Center

    Gilbert, Marianne C.

    2013-01-01

    This study asked the question: Do spiritual factors impact academic achievement? The subjects in this study were all students in grades 3, 4, 5, 6, 7, 8, 9, and 11, in Seventh-day Adventist schools in the United States and Bermuda, from 2006 to 2008. The compilation of the results of 75 questions as correlated to academic achievement, controlled…

  4. An Audit of Selected Private School Programs: Accelerated Christian Education, Alpha Omega, Mennonite Schools, Seventh-Day Adventist Schools, and A BEKA Instructional Resources.

    ERIC Educational Resources Information Center

    Alberta Dept. of Education, Edmonton.

    This report, commissioned by the Minister of Education of Alberta, reviews the programs of study and instructional materials used in four groups of approved private schools: schools using the Accelerated Christian Education curriculum; schools using the Alpha Omega program; Mennonite parochial schools; and Seventh Day Adventist schools. The review…

  5. A Comparison of the Academic Achievement of Seventh-Day Adventist Elementary Students by School Type: The Influence of Teacher, Student, Parent, and School Variables

    ERIC Educational Resources Information Center

    White, Denise Sue

    2009-01-01

    Enrollment in Seventh-day Adventist (SDA) schools is declining as is the number of schools and teachers. While there could be many reasons for this, one perception of SDA schools, held by parents, teachers, pastors, and school board members, is that students enrolled in schools with one, two, or three teachers do not achieve at the same rate as…

  6. Differences in Academic Achievement of Students Involved in Extracurricular Activities in Seventh-Day Adventist Schools in the United States and Bermuda

    ERIC Educational Resources Information Center

    Sandiford, Anderson P.

    2013-01-01

    This study examined differences in the academic performance of students in grades 6, 7, 8, 9, and 11 in Seventh-day Adventist schools in the United States and Bermuda based on their level of involvement in school music organizations--band or choir--and school sports--varsity or intramural--as measured by standardized achievement and ability tests.…

  7. Religious Orientation and Development amongst Adventist Youth.

    ERIC Educational Resources Information Center

    Donahue, Michael J.

    A questionnaire was administered to all 6th to 12th grade students attending Seventh-Day Adventist schools in North America. The questionnaire included the Age-Universal Intrinsic-Extrinsic Scale; the Faith Maturity Scale; an 18-item Adventist orthodoxy scale; and scales measuring the frequency of use of alcohol, marijuana, and tobacco, and of…

  8. The Effects of Health and Wellness on Academic Achievement and Cognitive Ability in Students Attending Seventh-Day Adventist Schools

    ERIC Educational Resources Information Center

    Williams, Patricia C.

    2011-01-01

    Healthful living has been a cornerstone of Seventh-day Adventist belief and practice almost from the very beginning of the church's history. The problem was that no one had studied the role healthful practices play in Seventh-day Adventist education using the entire Seventh-day Adventist student population. The correlations between four aspects of…

  9. The 'Adventist advantage'. Glendale Adventist Medical Center distinguishes itself.

    PubMed

    Botvin, Judith D

    2002-01-01

    Glendale Adventist Medical Center, Glendale, Calif., adopted an image-building campaign to differentiate the 450-bed hospital from its neighbors. This included the headline "Adventist Advantage," used in a series of sophisticated ads, printed in gold. In all their efforts, marketers consider the sensibilities of the sizable Armenian, Korean, Hispanic and Chinese populations. PMID:12134406

  10. The Relationship between Students' Perceptions of the Teaching and Learning Process and Academic Performance in Science of Seventh and Eighth Graders Enrolled in Seventh-Day Adventist Schools

    ERIC Educational Resources Information Center

    Burton, Larry D.; Kijai, Jimmy; Sargeant, Marcel A.

    2005-01-01

    This study investigated student perceptions of the 7th and 8th grade Adventist science education program and their relationship to achievement in science as defined by performance on the Iowa Test of Basic Skills. Findings revealed that students held generally poor perceptions of science education. Hierarchical regression analysis revealed 8…

  11. Constituents' Perceptions in Northen California Conference: Determining What Aspects of Seventh-Day Adventist Education Are Important

    ERIC Educational Resources Information Center

    von Pohle, Berit

    2013-01-01

    Schools in the Seventh-day Adventist (SDA) school system have experienced an enrollment decline of more than 25% over the past 30 years. A wide range of anecdotal explanations for this decline are shared by SDA members of the constituency as well as many views about ways to reverse the decline. There is little empirical data, however, to provide…

  12. The Saturn School: Technology's Cutting Edge.

    ERIC Educational Resources Information Center

    Hopkins, Michael

    1991-01-01

    Challenged by General Motors' creation of the Saturn automobile, St. Paul (Minnesota) educators created a new school by blending the best practices of existing schools with the most powerful and useful emerging technologies. In the Saturn School's learner-centered environment, each student develops a personal growth plan including academic,…

  13. Case Studies of Leading Edge Small Urban High Schools. Relevance Strategic Designs: 4. Boston Arts Academy

    ERIC Educational Resources Information Center

    Shields, Regis Anne; Ireland, Nicole; City, Elizabeth; Derderian, Julie; Miles, Karen Hawley

    2008-01-01

    This report is one of nine detailed case studies of small urban high schools that served as the foundation for the Education Resource Strategies (ERS) report "Strategic Designs: Lessons from Leading Edge Small Urban High Schools." These nine schools were dubbed "Leading Edge Schools" because they stand apart from other high schools across the…

  14. Case Studies of Leading Edge Small Urban High Schools. Core Academic Strategic Designs: 3. University Park Campus School

    ERIC Educational Resources Information Center

    Shields, Regis Anne; Ireland, Nicole; City, Elizabeth; Derderian, Julie; Miles, Karen Hawley

    2008-01-01

    This report is one of nine detailed case studies of small urban high schools that served as the foundation for the Education Resource Strategies (ERS) report "Strategic Designs: Lessons from Leading Edge Small Urban High Schools." These nine schools were dubbed "Leading Edge Schools" because they stand apart from other high schools across the…

  15. Case Studies of Leading Edge Small Urban High Schools. Core Academic Strategic Designs: 2. Noble Street Charter High School

    ERIC Educational Resources Information Center

    Shields, Regis Anne; Ireland, Nicole; City, Elizabeth; Derderian, Julie; Miles, Karen Hawley

    2008-01-01

    This report is one of nine detailed case studies of small urban high schools that served as the foundation for the Education Resource Strategies (ERS) report "Strategic Designs: Lessons from Leading Edge Small Urban High Schools." These nine schools were dubbed "Leading Edge Schools" because they stand apart from other high schools across the…

  16. New American High Schools: Profiles of the Nation's Leading Edge Schools.

    ERIC Educational Resources Information Center

    Department of Education, Washington, DC.

    This booklet profiles "leading edge" schools committed to ensuring that all students meet challenging academic standards and are prepared for college and careers. In 1996, these 10 New American High Schools were chosen by the U.S. Department of Education for their innovation and commitment to academic excellence. As these award-winning,…

  17. Personal Problems of Seventh-Day Adventist Academy Students

    ERIC Educational Resources Information Center

    Crosby, Ellen; Freed, Shirley; Gabriel, Elvin

    2006-01-01

    The Personal Problems Checklist for Adolescents (PPC-A) was administered to students in 14 Adventist academies for the purpose of determining the extent of their personal problems. Descriptive and inferential statistics were used to analyze the data. The results showed that the top 10 problems were: (1) poor study habits; (2) worrying about future…

  18. The Devil Takes a Look at Adventist Education.

    ERIC Educational Resources Information Center

    Knight, George R.

    2001-01-01

    Compares the educational philosophies of Hitler and the Seventh-day Adventist Church. While they both emphasize physical health, mental training, and character education, Hitler's motive was to promote a diabolical agenda. The article stresses the importance of reading deeper than mere words and practices to understand any author's philosophy and…

  19. Assessing the Practicality and Relevance of Adventist Educational Philosophy in a Contemporary Education Paradigm

    ERIC Educational Resources Information Center

    Jackman, W. Marc

    2014-01-01

    This article examines the key tenets of contemporary education philosophy and compares it to the principles of the Adventist educational philosophy. The intent is to determine whether Adventist educational philosophy aligns with the demands of contemporary education. In this vein, 10 key principles of contemporary education are first described.…

  20. Case Studies of Leading Edge Small Urban High Schools. Core Academic Strategic Designs: 1. Academy of the Pacific Rim

    ERIC Educational Resources Information Center

    Shields, Regis Anne; Ireland, Nicole; City, Elizabeth; Derderian, Julie; Miles, Karen Hawley

    2008-01-01

    This report is one of nine detailed case studies of small urban high schools that served as the foundation for the Education Resource Strategies (ERS) report "Strategic Designs: Lessons from Leading Edge Small Urban High Schools." These nine schools were dubbed "Leading Edge Schools" because they stand apart from other high schools across the…

  1. The Cutting Edge Technology Report: Designing Smarter Schools. [Videotape].

    ERIC Educational Resources Information Center

    2000

    This videotape highlights the extent to which school buildings are deteriorating in America and the problems this causes for teaching and learning, describes the Energy Smart School campaign, and details the factors needed in building an Energy Smart School. To build schools that last and to recoup some of the building expense, it suggests…

  2. Strategic Designs: Lessons from Leading Edge Small Urban High Schools

    ERIC Educational Resources Information Center

    Shields, Regis Anne; Miles, Karen Hawley

    2008-01-01

    Education Resource Strategies (ERS) works with school and district leaders to help them more strategically use resources--people, time, and money--to improve student performance. They have found that many school districts begin creating small high schools without a clear sense of how much they will spend or how to ensure that small schools…

  3. Mall Schools: A New Era for Cutting Edge Alternative Education

    ERIC Educational Resources Information Center

    Chalker, Christopher Scott; Stelsel, Kirk

    2008-01-01

    Education Resource Centers (ERCs) were established by the Simon Youth Foundation (SYF) as a means of providing economic opportunities and life choices for youth considered at risk through focused programs and initiatives with public school partners. In the current academic year there are 21 ERCs operating primarily in Simon Property Group (SPG)…

  4. The 10 Attributes of a "Leading-Edge" School District.

    ERIC Educational Resources Information Center

    Armstrong, William I.; Burkybile, Sharon A.

    1999-01-01

    Attributes of a successful school district include a sterling reputation; a high-quality management team; sound preparation for students' future; ability to attract, develop, and retain quality staff; a sound financial position; leadership that earns loyalty; hard and soft values; innovation and commitment; community stewardship; and character.…

  5. Computers Put a Journalism School on Technology's Leading Edge.

    ERIC Educational Resources Information Center

    Blum, Debra E.

    1992-01-01

    Since 1985, the University of Missouri at Columbia's School of Journalism has been developing a high-technology environment for student work, including word processing, electronic imaging, networked personal computers, and telecommunications. Some faculty worry that the emphasis on technology may overshadow the concepts, principles, and substance…

  6. The Black Seventh-Day Adventist exploratory health study.

    PubMed

    Nyenhuis, David L; Gorelick, Philip B; Easley, Cheryl; Garron, David C; Harris, Yvonne; Richardson, DeJuran; Raman, Rema; Levy, Paul

    2003-01-01

    African Americans are at high risk for stroke and dementia. Modifications of lifestyle, however, might lower this risk. The Seventh-Day Adventist (SDA) Church encourages both spiritual adherence and a healthy lifestyle. Members are encouraged to exercise and are discouraged from smoking, drinking alcoholic or caffeinated beverages, or eating meat. The present study describes an exploratory project in 2 Black SDA congregations (N = 82) designed to characterize the lifestyle, dietary, and spiritual health habits of these congregations, and to test the feasibility of collecting such information in the Black SDA community at large. Three separate data collection methods are described and evaluated. Data demonstrate that the sample differs significantly from the African-American community at large in dietary, lifestyle, and spiritual health habits. The Black SDA community represents a unique opportunity to test the effects of diet, lifestyle, and spirituality on risk for stroke and dementia.

  7. Vegetarian Dietary Patterns and Mortality in Adventist Health Study 2

    PubMed Central

    Orlich, Michael J.; Singh, Pramil N; Sabaté, Joan; Jaceldo-Siegl, Karen; Fan, Jing; Knutsen, Synnove; Beeson, W. Lawrence; Fraser, Gary E.

    2014-01-01

    Importance Some evidence suggests vegetarian dietary patterns may be associated with reduced mortality, but the relationship is not well established. Objective To evaluate the association between vegetarian dietary patterns and mortality. Design Prospective cohort study; mortality analysis by Cox proportional hazards regression, controlling for important demographic and lifestyle confounders. Setting Adventist Health Study 2 (AHS-2), a large North American cohort. Participants A total of 96 469 Seventh-day Adventist men and women recruited between 2002 and 2007, from which an analytic sample of 73 308 participants remained after exclusions. Exposures Diet was assessed at baseline by a quantitative food frequency questionnaire and categorized into 5 dietary patterns: nonvegetarian, semi-vegetarian, pesco-vegetarian, lacto-ovo–vegetarian, and vegan. Main Outcome and Measure The relationship between vegetarian dietary patterns and all-cause and cause-specific mortality; deaths through 2009 were identified from the National Death Index. Results There were 2570 deaths among 73 308 participants during a mean follow-up time of 5.79 years. The mortality rate was 6.05 (95% CI, 5.82–6.29) deaths per 1000 person-years. The adjusted hazard ratio (HR) for all-cause mortality in all vegetarians combined vs non-vegetarians was 0.88 (95% CI, 0.80–0.97). The adjusted HR for all-cause mortality in vegans was 0.85 (95% CI, 0.73–1.01); in lacto-ovo–vegetarians, 0.91 (95% CI, 0.82–1.00); in pesco-vegetarians, 0.81 (95% CI, 0.69–0.94); and in semi-vegetarians, 0.92 (95% CI, 0.75–1.13) compared with nonvegetarians. Significant associations with vegetarian diets were detected for cardiovascular mortality, noncardiovascular noncancer mortality, renal mortality, and endocrine mortality. Associations in men were larger and more often significant than were those in women. Conclusions and Relevance Vegetarian diets are associated with lower all-cause mortality and with some

  8. Forum Theatre and Parables: A Qualitative Field Experiment in a Seventh-Day Adventist Academy

    ERIC Educational Resources Information Center

    Freed, Dena Davis

    2012-01-01

    In this article, the author describes a qualitative field study designed to test the effectiveness of Forum Theatre (FT) as a cross-disciplinary approach to Biblical parabolic literature analysis for students enrolled in a Seventh-day Adventist (SDA) Academy. The author provides a brief overview of the theoretical framework of the study, the study…

  9. Committed Seventh-Day Adventist Students at Secular Institutions of Higher Education

    ERIC Educational Resources Information Center

    Anthony, LaShonda R.

    2013-01-01

    The experiences of Seventh-day Adventist students at secular universities was examined. Seven women and two men attending universities in Michigan and New York were interviewed. The researcher employed a heuristically guided phenomenological method to get rich descriptions of the participants' experiences in the secular university setting.…

  10. Beyond meatless, the health effects of vegan diets: findings from the Adventist cohorts.

    PubMed

    Le, Lap Tai; Sabaté, Joan

    2014-05-27

    Vegetarians, those who avoid meat, and vegans, additionally avoiding dairy and eggs, represent 5% and 2%, respectively, of the US population. The aim of this review is to assess the effects of vegetarian diets, particularly strict vegetarian diets (i.e., vegans) on health and disease outcomes. We summarized available evidence from three prospective cohorts of Adventists in North America: Adventist Mortality Study, Adventist Health Study, and Adventist Health Study-2. Non-vegetarian diets were compared to vegetarian dietary patterns (i.e., vegan and lacto-ovo-vegetarian) on selected health outcomes. Vegetarian diets confer protection against cardiovascular diseases, cardiometabolic risk factors, some cancers and total mortality. Compared to lacto-ovo-vegetarian diets, vegan diets seem to offer additional protection for obesity, hypertension, type-2 diabetes, and cardiovascular mortality. Males experience greater health benefits than females. Limited prospective data is available on vegetarian diets and body weight change. Large randomized intervention trials on the effects of vegetarian diet patterns on neurological and cognitive functions, obesity, diabetes, and other cardiovascular outcomes are warranted to make meaningful recommendations.

  11. Willingness to Participate in Organ Donation among Black Seventh-Day Adventist College Students

    ERIC Educational Resources Information Center

    Cort, Malcolm; Cort, David

    2008-01-01

    Objective and Participants: The authors studied a group of black and white Seventh-Day Adventist (SDA) college students (N = 334) to compare the power of religious socialization with racial socialization. Methods: The authors compared the levels of willingness to donate organs between black and nonblack students in an availability sample. Results:…

  12. Identifying Factors That Affect Higher Educational Achievements of Jamaican Seventh-Day Adventists

    ERIC Educational Resources Information Center

    Campbell, Samuel P.

    2011-01-01

    This mixed-method explanatory research examined factors that influenced Jamaican Seventh-day Adventist (SDA) members to pursue higher education. It sought to investigate whether the source of the motivation is tied to the Church's general philosophy on education or to its overall programs as experienced by the membership at large. The question of…

  13. Challenges to Seventh-Day Adventist Tertiary Education in the Caribbean

    ERIC Educational Resources Information Center

    Gardner, Trevor George

    2010-01-01

    The article briefly summarizes seven challenges that faces the Seventh Day Adventist (SDA) tertiary institutions in the Caribbean. There is no exhaustive discussion of the challenges but each is clearly articulated. There is no attempt to address solution but the discussion of each challenge, however, provides opportunity for several inferences…

  14. Attitudes toward Sexual Abstinence among Black Seventh-Day Adventist College Students

    ERIC Educational Resources Information Center

    Ashley, George; Ramirez, Octavio; Cort, Malcolm

    2013-01-01

    The purpose of this study was to identify Black Seventh-Day Adventist (SDA) college students' attitudes toward the concept of sexual abstinence. Attitude toward abstinence was operationalized as a dichotomy of acceptance or rejection of the concept as a way to order sexual behavior. The study utilized a convenience sample ("N" =…

  15. Beyond Meatless, the Health Effects of Vegan Diets: Findings from the Adventist Cohorts

    PubMed Central

    Le, Lap Tai; Sabaté, Joan

    2014-01-01

    Vegetarians, those who avoid meat, and vegans, additionally avoiding dairy and eggs, represent 5% and 2%, respectively, of the US population. The aim of this review is to assess the effects of vegetarian diets, particularly strict vegetarian diets (i.e., vegans) on health and disease outcomes. We summarized available evidence from three prospective cohorts of Adventists in North America: Adventist Mortality Study, Adventist Health Study, and Adventist Health Study-2. Non-vegetarian diets were compared to vegetarian dietary patterns (i.e., vegan and lacto-ovo-vegetarian) on selected health outcomes. Vegetarian diets confer protection against cardiovascular diseases, cardiometabolic risk factors, some cancers and total mortality. Compared to lacto-ovo-vegetarian diets, vegan diets seem to offer additional protection for obesity, hypertension, type-2 diabetes, and cardiovascular mortality. Males experience greater health benefits than females. Limited prospective data is available on vegetarian diets and body weight change. Large randomized intervention trials on the effects of vegetarian diet patterns on neurological and cognitive functions, obesity, diabetes, and other cardiovascular outcomes are warranted to make meaningful recommendations. PMID:24871675

  16. Christian Education in Chile: Is the Seventh-Day Adventist System at Risk?

    ERIC Educational Resources Information Center

    Grajales G., Tevni; Leon V., Vicente H.; Elias, Galiya

    2010-01-01

    Diverse perspectives with respect to Christian Education constitute a potential path for misunderstanding and contradictions; this study considers this situation in the context of a Seventh-day Adventist Christian system with students and parents from different religious perspectives in Chile. The parents/sponsors of the eighth graders were…

  17. Seventh-Day Adventist Teachers' Perceptions of Inclusion Classrooms and Identification of Challenges to Their Implementation

    ERIC Educational Resources Information Center

    Sargeant, Marcel A. A.; Berkner, Donna

    2015-01-01

    This qualitative study investigated the perceptions and challenges of Seventh-day Adventist teachers towards inclusion classrooms in the United States. For this study, 17 participants were interviewed using two 12-item interview protocols. The analysis of the teachers' responses revealed five key perceptions. First, teachers have positive…

  18. "Partners in Science": A Model Cooperative Program Introducing High School Teachers and Students to Leading-Edge Pharmaceutical Science

    ERIC Educational Resources Information Center

    Woska, Joseph R., Jr.; Collins, Danielle M.; Canney, Brian J.; Arcario, Erin L.; Reilly, Patricia L.

    2005-01-01

    "Partners in Science" is a cooperative program between Boehringer Ingelheim Pharmaceuticals, Inc. and area high schools in the community surrounding our Connecticut campus. It is a two-phase program that introduces high school students and teachers to the world of drug discovery and leading-edge pharmaceutical research. Phase 1 involves a series…

  19. Curriculum on the Edge of Survival: How Schools Fail to Prepare Students for Membership in a Democracy. 2nd Edition

    ERIC Educational Resources Information Center

    Heller, Daniel

    2012-01-01

    Typically, school curriculum has been viewed through the lens of preparation for the workplace or higher education, both worthy objectives. However, this is not the only lens, and perhaps not even the most powerful one to use, if the goal is to optimize the educational system. "Curriculum on the Edge of Survival, 2nd Edition," attempts to define…

  20. School Leadership Retention: A Study of Servant Leadership and School Leader Satisfaction

    ERIC Educational Resources Information Center

    Bovee, Jeffery A.

    2012-01-01

    The purpose of this quantitative correlation study was to find the relationship between the level of perceived servant leadership and the school leader job satisfaction in the North American Division (NAD) of Seventh-day Adventists P-12 schools. This quantitative correlation study utilized Laub's (1999) Organizational Leadership Assessment…

  1. Seroprevalence of Helicobacter pylori in Seventh-Day Adventists and other groups in Maryland. Lack of association with diet.

    PubMed

    Hopkins, R J; Russell, R G; O'Donnoghue, J M; Wasserman, S S; Lefkowitz, A; Morris, J G

    1990-11-01

    To evaluate the possible role of diet in the transmission of Helicobacter pylori, we compared H pylori seroprevalence among Seventh-Day Adventists (who are vegetarian and abstain from alcohol, caffeine, and meat; n = 94) and two non-Seventh-Day Adventist control groups (n = 168). With the use of an enzyme-linked immunosorbent assay H pylori antigen prepared in a French pressure cell, we found no difference in seroprevalence among these groups; however, seropositivity strongly correlated with age and black race. PMID:2241444

  2. Academic Workload Typologies and Burnout among Faculty in Seventh-Day Adventist Colleges and Universities in North America

    ERIC Educational Resources Information Center

    Gonzalez, Sylvia; Bernard, Hinsdale

    2006-01-01

    The focus of this investigation was to determine the possible relationship of workload typologies and other selected demographic variables to levels of burnout among full-time faculty in Seventh-day Adventist colleges and universities in North America. Four typologies of academic workload emerged from the study of the data. The results revealed…

  3. The Inclusion of Students with Actual or Perceived Learning Disabilities in the Seventh-Day Adventist Elementary Classroom

    ERIC Educational Resources Information Center

    Hale, Connie Lee

    2009-01-01

    This qualitative study investigated the effect of full inclusion of learning disabled students in Seventh-day Adventist (SDA) classrooms. Information on the dynamics of full inclusion was gathered through interviews with 15 elementary teachers in a Western Conference of SDA. Literature on inclusion in public and private educational systems was…

  4. Cyanocobalamin (vitamin B-12) status in Seventh-day Adventist ministers in Australia.

    PubMed

    Hokin, B D; Butler, T

    1999-09-01

    As part of the Adventist Ministers' Health Study, a series of cross-sectional surveys conducted in 1992, 1994, and 1997, the serum vitamin B-12 status of 340 Australian Seventh-day Adventist ministers was assessed in 1997. The ministers in the study participated voluntarily. Of this group, 245 were either lactoovovegetarians or vegans who were not taking vitamin B-12 supplements. Their mean vitamin B-12 concentration was 199 pmol/L (range: 58-538 pmol/L), 53% of whom had values below the reference range for the method used (171-850 pmol/L) and 73% of whom had values <221 pmol/L, the lower limit recommended by Herbert. Dual-isotope Schillings test results in 36 lactoovovegetarians with abnormally low vitamin B-12 concentrations indicated that dietary deficiency was the cause in 70% of cases. Data from the dietary questionnaires supported dietary deficiency as the cause of low serum vitamin B-12 in this population of lactoovovegetarians and vegans, 56 (23%) of whom consumed sufficient servings of vitamin B-12-containing foods to obtain the minimum daily maintenance allowance of the vitamin (1 microg). PMID:10479234

  5. Life on the Bleeding Edge: Philosophy, Practice, and Public Relations in Charter Schools

    ERIC Educational Resources Information Center

    Perreault, George

    2004-01-01

    Charter schools represent one of the most intriguing developments within public education in the past decade. Although they vary widely among themselves and differ from regular public schools in some regards, they also show many similarities. Consequently, many of the public relations strategies that work for other schools should also be useful…

  6. Dietary and hormonal interrelationships among vegetarian Seventh-Day Adventists and nonvegetarian men.

    PubMed

    Howie, B J; Shultz, T D

    1985-07-01

    The relationship between dietary nutrients and plasma testosterone, 5 alpha-dihydrotestosterone, estradiol-17 beta, luteinizing hormone, and prolactin levels was investigated in 12 Seventh-Day Adventist (SDA) vegetarian (SV), 10 SDA nonvegetarian (SNV), and 8 non-SDA nonvegetarian (NV) men. Fasting blood samples and 3-day dietary intake information were obtained from each subject. The SV subjects consumed significantly more crude and dietary fiber than the SNV and NV subjects, respectively. Plasma levels of testosterone and estradiol-17 beta were significantly lower in the SV than in the omnivores. Additionally, the plasma levels of testosterone and estradiol-17 beta of the combined groups (SV, SNV, and NV) revealed a significant negative relationship with their crude and dietary fiber intakes. These subjects hormonal milieu was related to specific dietary constituents, possibly leading to a decreased plasma concentration of androgen and estrogen in vegetarians. Implications include the possible modification of prostate cancer risk through dietary intervention.

  7. Dual Identity as a Two-Edged Sword: Identity Threat and Minority School Performance

    ERIC Educational Resources Information Center

    Baysu, Gulseli; Phalet, Karen; Brown, Rupert

    2011-01-01

    Some members of ethnic minority groups respond to identity threat in ways that are detrimental to their school career, while others persist despite an unwelcoming school environment. It was hypothesized that ethnic and national identities, as combined in "separated," "assimilated," or "dual identity" strategies, moderate consequences of identity…

  8. "Living on the Edge": A Case of School Reform Working for Disadvantaged Young Adolescents

    ERIC Educational Resources Information Center

    Smyth, John; McInerney, Peter

    2007-01-01

    This paper describes an instance of a disadvantaged (urban) Australian government school that realized it had little alternative but to try new approaches; "old ways" were not working. The paper describes an ensemble of school reform practices, philosophies and strategies that give young adolescents genuine ownership of their learning. This school…

  9. The Cutting Edge of Fun: Making Work Play at the New American School

    ERIC Educational Resources Information Center

    Sims, Christopher Otter

    2012-01-01

    This dissertation presents an ethnographic account of the launch of "The Downtown School for Design, Media, and Technology," one of the most prominent American school reform projects in recent years. Drawing on popular accounts about children and young people's pervasive affinity for digital media, and especially video games, the…

  10. Using Quality To Redesign School Systems: The Cutting Edge of Common Sense.

    ERIC Educational Resources Information Center

    Siegel, Peggy; Byrne, Sandra

    Quality is an important part of the process of managing institutional change. This book focuses on how Total Quality Management (TQM) as a management philosophy translates into practice, both in school systems and corporations. Data were obtained through observations and interviews conducted at 11 sites--4 companies and 7 educational facilities.…

  11. Pushing to the Edge: Rutgers Astrophysics Institute Motivates Talented High School Students

    ERIC Educational Resources Information Center

    Etkina, Eugenia; Matilsky, Terry; Lawrence, Michael

    2003-01-01

    The Rutgers Astrophysics Institute is a program in which gifted high school students learn about contemporary science and its methods, and conduct independent authentic research using real-time data. The students use the processes of science to acquire knowledge, and serve as cognitive apprentices to an expert astrophysicist. A variety of…

  12. Changing Workloads of Primary School Teachers: "I Seem to Live on the Edge of Chaos"

    ERIC Educational Resources Information Center

    Bridges, Sue; Searle, Annette

    2011-01-01

    The roles and workloads of teachers have been widely noted as changing considerably over recent decades. In this 2009 replication of a 1992 study, 379 New Zealand primary school educators are surveyed regarding their workloads, how these changed and their perceived sustainability. It investigates how respondents believe that educational reforms…

  13. Vegetarian diets and cardiovascular risk factors in black members of the Adventist Health Study-2

    PubMed Central

    Fraser, Gary; Katuli, Sozina; Anousheh, Ramtin; Knutsen, Synnove; Herring, Patti; Fan, Jing

    2014-01-01

    Objective To compare cardiovascular risk factors between vegetarians and non-vegetarians in black individuals living in the USA. Design A cross-sectional analysis of a sub-set of 592 black women and men enrolled in the Adventist Health Study-2 (AHS-2) cohort of Seventh-day Adventists. Setting Members of the AHS-2 cohort, who lived in all states of the USA and provinces of Canada. Subjects Black/African-American members of two sub-studies of AHS-2 where blood and physiological measurements were obtained. Results Of these women and men, 25% were either vegan or lacto-ovo-vegetarians (labelled ‘vegetarian/vegans’), 13 % were pesco-vegetarian and 62% were non-vegetarian. Compared with non-vegetarians, the vegetarian/vegans had odds ratios for hypertension, diabetes, high blood total cholesterol and high blood LDL-cholesterol of 0·56 (95% CI 0·36, 0·87), 0·48 (95% CI 0·24, 0·98), 0·42 (95% CI 0·27, 0·65) and 0·54 (95% CI 0·33, 0·89), respectively, when adjusted for age, gender, education, physical activity and sub-study. Corresponding odds ratios for obesity in vegetarian/vegans and pesco-vegetarians, compared with non-vegetarians, were 0·43 (95% CI 0·28, 0·67) and 0·47 (95% CI 0·27, 0·81), respectively; and for abdominal obesity 0·54 (95% CI 0·36, 0·82) and 0·50 (95% CI 0·29, 0·84), respectively. Results for pesco-vegetarians did not differ significantly from those of non-vegetarians for other variables. Further adjustment for BMI suggested that BMI acts as an intermediary variable between diet and both hypertension and diabetes. Conclusions As with non-blacks, these results suggest that there are sizeable advantages to a vegetarian diet in black individuals also, although a cross-sectional analysis cannot conclusively establish cause. PMID:24636393

  14. Partners in Science: A Model Cooperative Program Introducing High School Teachers and Students to Leading-Edge Pharmaceutical Science

    NASA Astrophysics Data System (ADS)

    Woska, Joseph R., Jr.; Collins, Danielle M.; Canney, Brian J.; Arcario, Erin L.; Reilly, Patricia L.

    2005-12-01

    Partners in Science is a cooperative program between Boehringer Ingelheim Pharmaceuticals, Inc. and area high schools in the community surrounding our Connecticut campus. It is a two-phase program that introduces high school students and teachers to the world of drug discovery and leading-edge pharmaceutical research. Phase 1 involves a series of lectures, tours, and demonstrations given by scientists within our research and development division (R&D). Phase 2 involves the selection of a small group of participants to intern for the summer in a research laboratory, working side by side with a scientist within R&D. In this manuscript, the specific aims, goals, and development of the Partners in Science program are described, as well as the syllabus/agenda, the logistics surrounding the operation of the program, and our shared personal experiences with students and teachers who have participated. Some of the pitfalls/problems associated with the program will be presented, and finally, the future direction of the program including areas of improvement and expansion are described.

  15. Tapestries: A Phenomenological Study on the Experience of Teaching in the Inclusive One-Teacher School.

    ERIC Educational Resources Information Center

    Bishop, Krystal

    This study was designed to better understand teachers as users of personal knowledge, examining teachers in inclusive one-teacher, Seventh Day Adventist schools. The study examined teachers' beliefs about teaching and learning, teachers' personal practical knowledge, teachers' professional identity, contextual factors that enabled or constrained…

  16. Transforming Patient Care in Adventist Health (West) Through Use of Information Technology

    SciTech Connect

    Huff, Wynelle J. , Bancarz, Gloria P.

    2009-07-01

    In 2002, Adventist Health(West) embarked upon a major project to better serve its communities by enhancing the safety, quality and clinical outcomes of the patients served by its 20 hospitals, i.e. the transformation of patient care through the use of information technology. The project is the implementation of the Cerner Millenium clinical information system (CIS) entitled Project IntelliCare. Budgeted allocations will go toward the training of 'super users' in 5-7 California Sites scheduled for installation and go-live of Phases I and II in 2005 and early 2006. Numerous super users in each hospital must be educated to provide support for every shift, every unit/department throughout the hospital. The hospitals experience significant costs associated with training these super users to thoroughly understand the CIS software, to train clinical users, to support the 'go-live' installations, and be there as a 'cheerleader to encourage and support all clinical users, and most importantly help guide users to transform their work processes using this information technology to provide the safest, highest quality care possible. Indeed, super users are critical to the success of Project IntelliCare. The 'super users' contributed significantly to the success of the 'go-live' impementations as well as ongoing support. Care has been transformed through clinicians use of information technology.

  17. Discover the Cosmos - Bringing Cutting Edge Science to Schools across Europe

    NASA Astrophysics Data System (ADS)

    Doran, Rosa

    2015-03-01

    The fast growing number of science data repositories is opening enormous possibilities to scientists all over the world. The emergence of citizen science projects is engaging in science discovery a large number of citizens globally. Astronomical research is now a possibility to anyone having a computer and some form of data access. This opens a very interesting and strategic possibility to engage large audiences in the making and understanding of science. On another perspective it would be only natural to imagine that soon enough data mining will be an active part of the academic path of university or even secondary schools students. The possibility is very exciting but the road not very promising. Even in the most developed nations, where all schools are equipped with modern ICT facilities the use of such possibilities is still a very rare episode. The Galileo Teacher Training Program GTTP, a legacy of IYA2009, is participating in some of the most emblematic projects funded by the European Commission and targeting modern tools, resources and methodologies for science teaching. One of this projects is Discover the Cosmos which is aiming to target this issue by empowering educators with the necessary skills to embark on this innovative path: teaching science while doing science.

  18. [Medicine on mission: The international health reform of Seventh-Day Adventists and their health care facilities in Sweden].

    PubMed

    Eklöf, Motzi

    2008-01-01

    The international non-conformist denomination, Seventh-day Adventists, have since their foundation in 1863, had a distinctive health care model for their members. The life-style has included vegetarian diet, abstinence from alcohol, tobacco and other drugs and the observance of a day of rest once a week. The health policy has striven to care for God's creation in the hope of resurrection at the Day of Judgment and to reform the conventional medical practice. The Adventists have pursued an extensive international health care system--from the start based on dietary and physical treatment methods, such as hydrotherapy, massage and physiotherapy--in line with the Christian mission. Health care establishments have been inaugurated around the world as a vehicle for enabling the Christian health care message to reach the upper classes. With Adventist and Doctor, John Harvey Kellogg's Battle Creek Sanatorium in Michigan as both inspirational source and educational institution, the health care mission--including a vegetarian health food industry, following in the footsteps of cornflakes--spread to the Nordic countries by the turn of the century, 1900. Skodsborgs Badesanatorium near Copenhagen became the model institution for several health care establishments in Sweden during the 1900's, such as Hultafors Sanatorium. The American-Nordic link has manifested itself through co-publication of papers, exchange of health care personnel and reporting to the central Adventist church. The American non-conformist domain as well as a private sphere of activity, aiming mainly from the outset at society's upper classes, has encountered certain difficulties in maintaining this distinction in Sweden's officially increasing secularised society, and in relation to a state health insurance and a publicly financed health care system. With the passing of time, the socioeconomic composition of patients at Hultafors became more heterogeneous, and conventional medical procedures were increasingly

  19. [Medicine on mission: The international health reform of Seventh-Day Adventists and their health care facilities in Sweden].

    PubMed

    Eklöf, Motzi

    2008-01-01

    The international non-conformist denomination, Seventh-day Adventists, have since their foundation in 1863, had a distinctive health care model for their members. The life-style has included vegetarian diet, abstinence from alcohol, tobacco and other drugs and the observance of a day of rest once a week. The health policy has striven to care for God's creation in the hope of resurrection at the Day of Judgment and to reform the conventional medical practice. The Adventists have pursued an extensive international health care system--from the start based on dietary and physical treatment methods, such as hydrotherapy, massage and physiotherapy--in line with the Christian mission. Health care establishments have been inaugurated around the world as a vehicle for enabling the Christian health care message to reach the upper classes. With Adventist and Doctor, John Harvey Kellogg's Battle Creek Sanatorium in Michigan as both inspirational source and educational institution, the health care mission--including a vegetarian health food industry, following in the footsteps of cornflakes--spread to the Nordic countries by the turn of the century, 1900. Skodsborgs Badesanatorium near Copenhagen became the model institution for several health care establishments in Sweden during the 1900's, such as Hultafors Sanatorium. The American-Nordic link has manifested itself through co-publication of papers, exchange of health care personnel and reporting to the central Adventist church. The American non-conformist domain as well as a private sphere of activity, aiming mainly from the outset at society's upper classes, has encountered certain difficulties in maintaining this distinction in Sweden's officially increasing secularised society, and in relation to a state health insurance and a publicly financed health care system. With the passing of time, the socioeconomic composition of patients at Hultafors became more heterogeneous, and conventional medical procedures were increasingly

  20. Trans fatty acid intake is related to emotional affect in the Adventist Health Study-2.

    PubMed

    Ford, Patricia A; Jaceldo-Siegl, Karen; Lee, Jerry W; Tonstad, Serena

    2016-06-01

    Trans fatty acids in Western diets increase health risks, and have been associated with the risk of depression. We hypothesized that intakes of trans fatty acids (primarily from margarines and baked goods) were inversely associated with positive affect and positively associated with negative affect in a longitudinal study. Church attendees residing in North America completed a food frequency questionnaire in 2002-6 as part of the Adventist Health Study-2. A subset in which we excluded participants with established cardiovascular disease (n=8,771) completed the Positive and Negative Affect Schedule (PANAS) in 2006-7. The associations between dietary intakes of fatty acids to positive and negative affect were tested with linear regression analysis controlling for age, gender, ethnicity, education, body mass index, exercise, sleep, sleep squared, Mediterranean diet, total energy intake and alcohol. Intakes of trans fatty acids were inversely associated with positive affect (β=-0.06, B=-0.27 [95% CI -0.37, -0.17], p<.001) and positively associated with negative affect (β=0.05, B=0.21 [95% CI 0.11, 0.31], p<.001). In comparison, we found no association between n-3 polyunsatured fatty acids (PUFA) intakes with affect. The n-6:n-3 PUFA ratio was inversely associated with positive affect (β=-0.03, B=-0.34 [95% CI -0.58, -0.10], p=0.006). The findings suggest that a lower dietary trans fatty acid intake has beneficial effects on emotional affect while the n-6: n-3 ratio is detrimental to positive affect. PMID:27188896

  1. Tree Nuts Are Inversely Associated with Metabolic Syndrome and Obesity: The Adventist Health Study-2

    PubMed Central

    Jaceldo-Siegl, Karen; Haddad, Ella; Oda, Keiji; Fraser, Gary E.; Sabaté, Joan

    2014-01-01

    Objective To examine the relationships of nut consumption, metabolic syndrome (MetS), and obesity in the Adventist Health Study-2, a relatively healthy population with a wide range of nut intake. Research Design and Methods Cross-sectional analysis was conducted on clinical, dietary, anthropometric, and demographic data of 803 adults. MetS was defined according to the American Heart Association and the National Heart, Lung, and Blood Institute diagnostic criteria. We assessed intake of total nuts, tree nuts and peanuts, and also classified subjects into low tree nut/low peanut (LT/LP), low tree/high peanut (LT/HP), high tree nut/high peanut (HT/HP), and high tree/low peanut (HT/LP) consumers. Odds ratios were estimated using multivariable logistic regression. Results 32% of subjects had MetS. Compared to LT/LP consumers, obesity was lower in LT/HP (OR = 0.89; 95% CI = 0.53, 1.48), HT/HP (OR = 0.63; 95% CI = 0.40, 0.99) and HT/LP (OR = 0.54; 95% CI = 0.34, 0.88) consumers, p for trend = 0.006. For MetS, odds ratios (95% CI) were 0.77 (0.47, 1.28), 0.65 (0.42, 1.00) and 0.68 (0.43, 1.07), respectively (p for trend = 0.056). Frequency of nut intake (once/week) had significant inverse associations with MetS (3% less for tree nuts and 2% less for total nuts) and obesity (7% less for tree nuts and 3% less for total nuts). Conclusions Tree nuts appear to have strong inverse association with obesity, and favorable though weaker association with MetS independent of demographic, lifestyle and dietary factors. PMID:24416351

  2. Body Mass Index at Age 20 and Subsequent Childbearing: The Adventist Health Study-2

    PubMed Central

    Knutsen, Synnøve F.; Oda, Keiji; Fraser, Gary E.

    2013-01-01

    Abstract Background Some epidemiological, clinical, and laboratory studies suggest that underweight and obesity impact fertility. Methods This is cross-sectional study of 33,159 North American Adventist women, who were nulliparous at age 20 years and who, as a group, have a healthy lifestyle. Logistic regression analysis was used to assess how body mass index (BMI, kg/m2) at age 20 was related to never becoming pregnant, never giving birth to a living child, or not giving birth to a second or third child. Results A total of 4954 (15%) of the women reported never becoming pregnant (nulligravidity) and 7461 (23%) women remained nulliparous. Underweight (BMI<18.5 kg/m2) at age 20 was associated with approximately 13% increased risk of nulligravidity or nulliparity. Women with BMI≥32.5 kg/m2 when aged 20 had 2.5 (95% CI: 2.0, 3.1) times increased odds of nulliparity compared to women with BMI 20–24.9 kg/m2. Increased risk was found for all groups of overweight women (BMI≥25 kg/m2). However, if the women gave birth to one live child after age 20, BMI≥32.5 kg/m2 at age 20 had less impact (OR 1.6 [95% CI: 1.2, 2.2]) on the likelihood of not delivering a second child. In women who delivered two living children, obesity at age 20 had no bearing on the odds of having a third child. Conclusions Obesity and, to a lesser extent, underweight at age 20 increases the nulliparity rate. The results underscore the importance of a healthy weight in young women. PMID:23611121

  3. Dietary status of Seventh-Day Adventist vegetarian and non-vegetarian elderly women.

    PubMed

    Nieman, D C; Underwood, B C; Sherman, K M; Arabatzis, K; Barbosa, J C; Johnson, M; Shultz, T D

    1989-12-01

    The purpose of this study was to investigate nutrient intakes of Seventh-Day Adventist elderly women who were similar in many demographic and life-style factors except for choice of diet. Twenty-three vegetarian and 14 non-vegetarian elderly women (mean +/- standard error ages 72.2 +/- 1.3 and 71.1 +/- 1.4 years, respectively) were recruited on the basis of several selection criteria, including race, religion, education, geographic area, Quetelet index, self-reported absence of major chronic disease and use of medications, and physical activity. Average years +/- SE of adherence to dietary regimens were 47.0 +/- 2.9 and 71.2 +/- 1.4 in the vegetarian and non-vegetarian groups, respectively. Results from analysis of 7-day food records showed that vegetarians consumed significantly less cholesterol, saturated fatty acids, and caffeine but more carbohydrate, dietary fiber, magnesium, vitamins E and A, thiamin, pantothenic acid, copper, and manganese than non-vegetarians (p less than .05). On the basis of group means, 67% of the Recommended Dietary Allowance was met for all nutrients except zinc and vitamin D in both groups, and vitamins B-6, folacin, and vitamin E in the non-vegetarians. Compared with non-vegetarians, vegetarians had significantly lower serum glucose (5.18 +/- 0.11 vs. 4.65 +/- 0.09 mmol/L), low-density-lipoprotein cholesterol (4.08 +/- 0.25 vs. 3.34 +/- 0.19 mmol/L), and total cholesterol levels (6.46 +/- 0.27 vs. 5.62 +/- 0.21 mmol/L) (p less than .05). In summary, when healthy elderly vegetarian women were compared with closely matched non-vegetarian peers, the vegetarian diet was associated with improved nutrient intake and associated reductions in blood glucose and lipid levels.

  4. Soy isoflavone intake and the likelihood of ever becoming a mother: the Adventist Health Study-2

    PubMed Central

    Jacobsen, Bjarne K; Jaceldo-Siegl, Karen; Knutsen, Synnøve F; Fan, Jing; Oda, Keiji; Fraser, Gary E

    2014-01-01

    Objectives As little is known about the possible relationship between the intake of phytoestrogens and female fertility, we investigated the relationship between soy isoflavone intake and the risk of nulliparity and nulligravidity. Methods A cross-sectional study of 11,688 North American Adventist women aged 30–50 years old with data regarding childbearing. These women were, as a group, characterized by a high proportion (54%) of vegetarians and a healthy lifestyle with a very low prevalence of smoking and alcohol use. Results The mean isoflavone intake (17.9 mg per day) was very high compared to other Western populations. Only 6% of the women indicated no intake of isoflavones. We found, after adjustment for age, marital status, and educational level, an inverse relationship (P=0.05) between isoflavone intake and the likelihood of ever having become a mother. In women with high (≥40 mg/day) isoflavone intake (12% of this group of women), the adjusted lifetime probability of giving birth to a live child was reduced by approximately 3% (95% CI: 0, 7) compared to women with low (<10 mg/day) intake. No relationships were found between the isoflavone intake and parity or age at first delivery in parous women. A similar inverse relationship (P=0.03) was found between the isoflavone intake and the risk of nulligravidity with a 13% (95% CI: 2, 26) higher risk of never have been pregnant in women with high (≥40 mg/day) isoflavone intake. These relationships were found mainly in women who reported problems becoming pregnant. Conclusion The findings suggest that a high dietary isoflavone intake may have significant impact on fertility. PMID:24741329

  5. What Does it Mean to be a Christian? Exploring the Religious Identity of Intrinsically and Extrinsically Religious Black Seventh-Day Adventist University Students

    ERIC Educational Resources Information Center

    Ramirez, Octavio; Ashley, George; Cort, Malcolm

    2014-01-01

    This study explored the religious identity of Black Seventh-day Adventist University students and the elements that helped form their religious identity. The unidirectional, bidirectional and channeling models of socialization was used to describe the formation of religious identity. The data were collected in two stages. At the first stage, a…

  6. Religiosity, dietary habit, intake of fruit and vegetable, and vegetarian status among Seventh-Day Adventists in West Malaysia.

    PubMed

    Tan, Min-Min; Chan, Carina K Y; Reidpath, Daniel D

    2016-08-01

    Religion has been shown to be salutary on health, and a possible link between religion and positive health outcomes is diet. Research has shown that religiosity is associated with better diet but most studies were conducted in a multi-denominational context, which might be confounded with theological differences. This study examined the relationship between religiosity and diet within a homogenous group of believers. Data from survey of 574 Seventh-Day Adventists residing in West Malaysia, aged 18-80, were analyzed using multiple regressions. While none of the religious variables were significantly associated with fruit and vegetable intake, a higher level of religiosity was associated with a better dietary habit and vegetarian status. The mixed relationship between religiosity and diet suggest that further research is needed to explore how religion might influence the diet of adherents. PMID:27010212

  7. Urinary 1-methylhistidine is a marker of meat consumption in Black and in White California Seventh-day Adventists.

    PubMed

    Myint, T; Fraser, G E; Lindsted, K D; Knutsen, S F; Hubbard, R W; Bennett, H W

    2000-10-15

    Meat consumption predicts risk of several chronic diseases. The authors validate the accuracy of meat consumption reported by food frequency questionnaires and the mean of eight 24-hour recalls, using urinary methylhistidine excretion, in 55 Black and 71 White Adventist subjects in Los Angeles and San Diego, California, in 1994-1997. 1-Methylhistidine excretion predicts vegetarian status in Black (p = 0.02) and in White (p = 0.005) subjects. Spearman's correlation coefficients between 1-methylhistidine and estimated meat consumption were usually between 0.4 and 0.6 for both food frequency questionnaires and 24-hour recall data. This is despite the chance collection of dietary recalls and urines from omnivores on meatless days.

  8. Short- and long-term reliability of adult recall of vegetarian dietary patterns in the Adventist Health Study-2 (AHS-2).

    PubMed

    Teixeira Martins, Marcia C; Jaceldo-Siegl, Karen; Fan, Jing; Singh, Pramil; Fraser, Gary E

    2015-01-01

    Past dietary patterns may be more important than recent dietary patterns in the aetiology of chronic diseases because of the long latency in their development. We developed an instrument to recall vegetarian dietary patterns during the lifetime and examined its reliability of recall over 5·3 and 32·6 years on average. The short-term/5-year recall ability study (5-RAS) was done using 24 690 participants from the cohort of the Adventist Health Study-2 (mean age 62·2 years). The long-term/33-year recall ability study (33-RAS) included an overlap population of 1721 individuals who joined the Adventist Health Study-1 and Adventist Health Study-2 (mean age 72·5 years). Spearman correlation coefficients for recall of vegetarian status were 0·78 and 0·72 for the 5-RAS and 33-RAS, respectively, when compared with 'reference' data. For both time periods sensitivity and positive predictive values were highest for the lacto-ovo-vegetarian and non-vegetarian patterns (vegans, lacto-ovo-vegetarians, pesco-vegetarians, semi-vegetarians and non-vegetarians). In the 5-RAS analyses, male, non-black, younger, and more educated participants, lifetime Adventists, and those with more stability of consumption of animal products generally showed higher recall ability. Somewhat similar tendencies were shown for the 33-RAS analyses. Our findings show that the instrument has higher reliability for recalled lacto-ovo-vegetarian and non-vegetarian than for vegan, semi- and pesco-vegetarian dietary patterns in both short- and long-term recalls. This is in part because these last dietary patterns were greatly contaminated by recalls that correctly would have belonged in the adjoining category that consumed more animal products. PMID:26097699

  9. EDGE (Experiential Discoveries in Geoscience Education) Field Course Provides Alaskan High School and Middle School students with Earth Science and GIS Skills for Science Fair Projects and a College Experience

    NASA Astrophysics Data System (ADS)

    Connor, C. L.; Prakash, A.; Brownlee, M.; Nagorski, S.; Walling, R.

    2006-12-01

    For this outreach project we created watershed scale field activities in the Mendenhall Glacier system in Juneau, Alaska to introduce pre-college students to earth surface processes. These activities were designed to teach field data collection methods and to provide experiences that included exposure to the disciplines of glaciology, hydrology, and geomorphology. Students used their own observations to understand the on-going effects of warming climate in southeastern Alaska. Twenty seven, pre-college students from throughout the state participated in a 5-day, two-credit, introductory college-level course. This course was designed to introduce them to earth science as practiced in the field. Students divided their time between field sessions with data collection and indoor GIS labs. EDGE field excursions enabled students to learn about glacial geomorphology from river rafts, to collect stream discharge and other hydrologic data in local streams, and to integrate glacier recession observations with GPS waypoints collected from observed recessional positions. In labs at the University of Alaska Southeast campus, EDGE students were introduced to the fundamentals of ArcGIS. They downloaded their GPS waypoints onto modern and historic maps. They analyzed their stream flow data and created dynamic maps using their own observations in the field. During Fall 2006 semester, the students will generate earth science projects in their villages and towns that they can complete and present to their peers. EDGE teachers who attended a 10 day workshop in June will mentor their EDGE students. EDGE teachers and students will return to the UAS Juneau campus in March 2007 for a symposium. EGDE students will present their projects to Juneau area undergraduates and Juneau School District K-12 classes. In addition EDGE high school students will have the option to enter and compete in the Southeast Alaska Regional Science Fair held the same weekend. Funding from the National Science

  10. Look in the Mythic Mirror: 10-Week Middle School Curriculum Unit. ArtsEdge Curricula, Lessons and Activities.

    ERIC Educational Resources Information Center

    Ashburn, Jennifer; Ayers, Mary Jane; Born-Ozment, Susan; Karsten, Jayne; Maeda, Sheri

    This 10-week middle school curriculum unit for grades 6-8, integrating concepts, materials, and content from language arts, music, and visual arts, provides a set of specific instructional plans relative to the study of myths (often a content area in middle school grades across the country). All the sample lessons and examples in the curriculum…

  11. Addressing Health Literacy Challenges With a Cutting-Edge Infectious Disease Curriculum for the High School Biology Classroom

    PubMed Central

    Jacque, Berri; Koch-Weser, Susan; Faux, Russell; Meiri, Karina

    2016-01-01

    This study reports the secondary analysis of evaluation data from an innovative high school biology curriculum focused on infectious disease (ID) to examine the health literacy implications of teaching claims evaluation, data interpretation, and risk assessment skills in the context of 21st-Century health science. The curriculum was implemented between 2010 and 2013 in Biology II classes held in four public high schools (three in Massachusetts and one in Ohio), plus a private school in Virginia. A quasi-experimental design was used in which student participants (n = 273) were compared to an age-matched, nonparticipant, peer group (N = 125). Participants in each school setting demonstrated increases in conceptual content knowledge (Cohen’s d > 1.89) as well as in understanding how to apply scientific principles to health claims evaluation and risk assessment (Cohen’s d > 1.76) and in self-efficacy toward learning about ID (Cohen’s d > 2.27). Participants also displayed enhanced communication about ID within their social networks relative to the comparison group (p < .05). The data show that integrating the claims evaluation, data interpretation, and risk assessment skills critical for 21st-century health literacy health into high school biology classrooms is effective at fostering both the skills and self-efficacy pertinent to health literacy learning in diverse populations. PMID:26194205

  12. Addressing Health Literacy Challenges With a Cutting-Edge Infectious Disease Curriculum for the High School Biology Classroom.

    PubMed

    Jacque, Berri; Koch-Weser, Susan; Faux, Russell; Meiri, Karina

    2016-02-01

    This study reports the secondary analysis of evaluation data from an innovative high school biology curriculum focused on infectious disease (ID) to examine the health literacy implications of teaching claims evaluation, data interpretation, and risk assessment skills in the context of 21st-Century health science. The curriculum was implemented between 2010 and 2013 in Biology II classes held in four public high schools (three in Massachusetts and one in Ohio), plus a private school in Virginia. A quasi-experimental design was used in which student participants (n = 273) were compared to an age-matched, nonparticipant, peer group (N = 125). Participants in each school setting demonstrated increases in conceptual content knowledge (Cohen's d > 1.89) as well as in understanding how to apply scientific principles to health claims evaluation and risk assessment (Cohen's d > 1.76) and in self-efficacy toward learning about ID (Cohen's d > 2.27). Participants also displayed enhanced communication about ID within their social networks relative to the comparison group (p < .05). The data show that integrating the claims evaluation, data interpretation, and risk assessment skills critical for 21st-century health literacy health into high school biology classrooms is effective at fostering both the skills and self-efficacy pertinent to health literacy learning in diverse populations.

  13. Comparison of the fecal microflora of Seventh-Day Adventists with individuals consuming a general diet. Implications concerning colonic carcinoma.

    PubMed

    Goldberg, M J; Smith, J W; Nichols, R L

    1977-07-01

    Qualitative and quantitative fecal microflora was studied in a double blind fashion in 28 subjects. Fourteen were Seventh-Day Adventists, who were strict vegetarians, while the remaining 14 subjects were individuals consuming a general western diet. No statistically significant differences were identified in the fecal microflora of the two groups. The bacteriologic analysis included total aerobes and total anaerobes as well as each of the major fecal aerobes and anaerobes. This study seems to indicate that the dietary intake of animal fat and protein does not significantly alter the fecal microflora, a possibility which has previously been suggested as being part of the explanation for the higher incidence of colonic carcinoma in those who consume meat compared with vegetarians. It does not, however, invalidate the concept that dietary animal fat does increase bile acid degradation within the gastrointestinal tract, a factor which has been related to colon cancer. Future studies should be directed at identifying the factors that may be present in the gastrointestinal tracts of vegetarians which modify the ability of their colonic microflora to degrade bile acids, an essential step in the production of intraluminal carcinogens or co-carcinogens.

  14. Addressing Health Literacy Challenges with a Cutting-Edge Infectious Disease Curriculum for the High School Biology Classroom

    ERIC Educational Resources Information Center

    Jacque, Berri; Koch-Weser, Susan; Faux, Russell; Meiri, Karina

    2016-01-01

    This study reports the secondary analysis of evaluation data from an innovative high school biology curriculum focused on infectious disease (ID) to examine the health literacy implications of teaching claims evaluation, data interpretation, and risk assessment skills in the context of 21st-Century health science. The curriculum was implemented…

  15. "Can I Come in Here?" Winston's Discovery of Edge-of-School Spaces and Meaningful Literacy Engagement

    ERIC Educational Resources Information Center

    Johnson, Latrise

    2014-01-01

    Literacy classrooms are places of tension in the shaping of literate identities for Black male students because of classroom and cultural mismatch, racialized literacy beliefs and deficit views of Black male literacy achievement. However, research on connections between students' out-of-school literacy and academic literacy participation tells a…

  16. Edge Bioinformatics

    SciTech Connect

    Lo, Chien-Chi

    2015-08-03

    Edge Bioinformatics is a developmental bioinformatics and data management platform which seeks to supply laboratories with bioinformatics pipelines for analyzing data associated with common samples case goals. Edge Bioinformatics enables sequencing as a solution and forward-deployed situations where human-resources, space, bandwidth, and time are limited. The Edge bioinformatics pipeline was designed based on following USE CASES and specific to illumina sequencing reads. 1. Assay performance adjudication (PCR): Analysis of an existing PCR assay in a genomic context, and automated design of a new assay to resolve conflicting results; 2. Clinical presentation with extreme symptoms: Characterization of a known pathogen or co-infection with a. Novel emerging disease outbreak or b. Environmental surveillance

  17. Edge Bioinformatics

    2015-08-03

    Edge Bioinformatics is a developmental bioinformatics and data management platform which seeks to supply laboratories with bioinformatics pipelines for analyzing data associated with common samples case goals. Edge Bioinformatics enables sequencing as a solution and forward-deployed situations where human-resources, space, bandwidth, and time are limited. The Edge bioinformatics pipeline was designed based on following USE CASES and specific to illumina sequencing reads. 1. Assay performance adjudication (PCR): Analysis of an existing PCR assay in amore » genomic context, and automated design of a new assay to resolve conflicting results; 2. Clinical presentation with extreme symptoms: Characterization of a known pathogen or co-infection with a. Novel emerging disease outbreak or b. Environmental surveillance« less

  18. Comparison of polyphenol intakes according to distinct dietary patterns and food sources in the Adventist Health Study-2 cohort.

    PubMed

    Burkholder-Cooley, Nasira; Rajaram, Sujatha; Haddad, Ella; Fraser, Gary E; Jaceldo-Siegl, Karen

    2016-06-01

    Evidence suggests a relationship between polyphenol intake and health benefits. Polyphenol intake among a large US cohort with diverse dietary practices ranging from meatless to omnivorous diets has not been previously evaluated. The primary aim of this study was to compare polyphenol intakes of several vegetarian and non-vegetarian dietary patterns and to assess phenolic intake by food source. To characterise dietary intake, a FFQ was administered to 77 441 participants of the Adventist Health Study-2. Dietary patterns were defined based on the absence of animal food consumption as vegan, lacto-ovo-vegetarian, pesco-vegetarian, semi-vegetarian and non-vegetarian. Polyphenol intakes were calculated based on chromatography-derived polyphenol content data of foods from Phenol-Explorer, US Department of Agriculture databases and relevant literature. Results revealed a mean unadjusted total polyphenol intake of 801 (sd 356) mg/d, and the main foods contributing to polyphenol intakes were coffee, fruits and fruit juices. Total polyphenol intake differed significantly between dietary patterns, with phenolic acids from coffee contributing the greatest variation. The dominant classes and sources of dietary polyphenols differed between vegetarian and non-vegetarian diets. Flavonoid intake was the highest among pesco-vegetarians, and phenolic acid intake was the highest among non-vegetarians. In addition, coffee consumers appeared to have a different dietary profile than non-coffee consumers, including greatly reduced contribution of fruits, vegetables and legumes to total phenolic intake. Coffee drinkers were more likely to be non-vegetarians, which explained several of these observations. Further evaluating these differences may be important in identifying relationships between plant-based diets and health outcomes. PMID:27080936

  19. Involving Minority High School Students in Cutting Edge Research through C-DEBI, an NSF-National Science and Technology Center

    NASA Astrophysics Data System (ADS)

    Singer, E.; Edwards, K. J.

    2012-12-01

    The Center for Dark Energy Biosphere Investigations (C-DEBI) was established as a National Science and Technology Center (NTC) funded by NSF in 2009. Its mission is to explore life beneath the seafloor and make transformative discoveries that advance science, benefit society, and inspire people of all ages and origins. Thanks to the multi-institutional character of C-DEBI, the Center has not only started a collaborative framework for experimental and exploratory research, but also targets education programs at the K-12, undergraduate, graduate and postdoctoral levels involving biogeochemists, microbiologists, geochemists and geologists. An example for this is the introduction of deep biosphere research into the K-12 classroom. In this context, C-DEBI has collaborated with teachers from the Animo Leadership High School in Inglewood, which is ranked 27th within California and has a total minority enrollment of 99%, to adapt Marine Biology classes and introduce latest Deep Biosphere Science discoveries. Three high school students participated in a pilot project over 6 months to gain hands-on experience in an ongoing study in a Marine Microbiology laboratory at University of Southern California. Graduate and postdoctoral students from the Departments of Biological and Earth Sciences supervised theory, praxis and project design, which was aimed at culturing strains of Marinobacter, one of the most ubiquitous marine microbial genera, and preparing extracted DNA for sequencing using the latest Ion Torrent Technology. Students learned about the interdisciplinary global context of the study and gained experience in laboratory procedures, including basic aseptical techniques, molecular biology methods, and cutting-edge sequencing Technology, as well as problem-solving and creative thinking in project preparation and conduction. This hands-on training included discussions about the 'Whys' and 'Hows' in today's research with respect to their specific project, but also from a

  20. Edge detection

    NASA Astrophysics Data System (ADS)

    Hildreth, E. C.

    1985-09-01

    For both biological systems and machines, vision begins with a large and unwieldly array of measurements of the amount of light reflected from surfaces in the environment. The goal of vision is to recover physical properties of objects in the scene such as the location of object boundaries and the structure, color and texture of object surfaces, from the two-dimensional image that is projected onto the eye or camera. This goal is not achieved in a single step: vision proceeds in stages, with each stage producing increasingly more useful descriptions of the image and then the scene. The first clues about the physical properties of the scene are provided by the changes of intensity in the image. The importance of intensity changes and edges in early visual processing has led to extensive research on their detection, description and use, both in computer and biological vision systems. This article reviews some of the theory that underlies the detection of edges, and the methods used to carry out this analysis.

  1. The Problem of the Edge.

    ERIC Educational Resources Information Center

    Faatz, Judith A.

    1998-01-01

    Describes a field study in a local ecosystem which allows high school students to investigate the edge effect, where a meadow and a forest meet. Students measure soil moisture content, soil temperature, air temperature, relative humidity, wind intensity, and illumination level. Teachers can help students apply their findings to understand problems…

  2. The Edge

    NASA Technical Reports Server (NTRS)

    2006-01-01

    6 April 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the edge (running diagonally from the lower left to the upper right) of a trough, which is part of a large pit crater complex in Noachis Terra. This type of trough forms through the collapse of surface materials into the subsurface, and often begins as a series of individual pit craters. Over time, continued collapse increases the diameter of individual pits until finally, adjacent pits merge to form a trough such as the one captured in this image. The deep shadowed area is caused in part by an overhang; layered rock beneath this overhang is less resistant to erosion, and thus has retreated tens of meters backward, beneath the overhang. A person could walk up inside this 'cave' formed by the overhanging layered material.

    Location near: 47.0oS, 355.7oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  3. Unified EDGE

    SciTech Connect

    2007-06-18

    UEDGE is an interactive suite of physics packages using the Python or BASIS scripting systems. The plasma is described by time-dependent 2D plasma fluid equations that include equations for density, velocity, ion temperature, electron temperature, electrostatic potential, and gas density in the edge region of a magnetic fusion energy confinement device. Slab, cylindrical, and toroidal geometries are allowed, and closed and open magnetic field-line regions are included. Classical transport is assumed along magnetic field lines, and anomalous transport is assumed across field lines. Multi-charge state impurities can be included with the corresponding line-radiation energy loss. Although UEDGE is written in Fortran, for efficient execution and analysis of results, it utilizes either Python or BASIS scripting shells. Python is easily available for many platforms (http://www.Python.org/). The features and availability of BASIS are described in “Basis Manual Set” by P.F. Dubois, Z.C. Motteler, et al., Lawrence Livermore National Laboratory report UCRL-MA-1 18541, June, 2002 and http://basis.llnl.gov. BASIS has been reviewed and released by LLNL for unlimited distribution. The Python version utilizes PYBASIS scripts developed by D.P. Grote, LLNL. The Python version also uses MPPL code and MAC Perl script, available from the public-domain BASIS source above. The Forthon version of UEDGE uses the same source files, but utilizes Forthon to produce a Python-compatible source. Forthon has been developed by D.P. Grote at LBL (see http://hifweb.lbl.gov/Forthon/ and Grote et al. in the references below), and it is freely available. The graphics can be performed by any package importable to Python, such as PYGIST.

  4. Unified EDGE

    2007-06-18

    UEDGE is an interactive suite of physics packages using the Python or BASIS scripting systems. The plasma is described by time-dependent 2D plasma fluid equations that include equations for density, velocity, ion temperature, electron temperature, electrostatic potential, and gas density in the edge region of a magnetic fusion energy confinement device. Slab, cylindrical, and toroidal geometries are allowed, and closed and open magnetic field-line regions are included. Classical transport is assumed along magnetic field lines,more » and anomalous transport is assumed across field lines. Multi-charge state impurities can be included with the corresponding line-radiation energy loss. Although UEDGE is written in Fortran, for efficient execution and analysis of results, it utilizes either Python or BASIS scripting shells. Python is easily available for many platforms (http://www.Python.org/). The features and availability of BASIS are described in “Basis Manual Set” by P.F. Dubois, Z.C. Motteler, et al., Lawrence Livermore National Laboratory report UCRL-MA-1 18541, June, 2002 and http://basis.llnl.gov. BASIS has been reviewed and released by LLNL for unlimited distribution. The Python version utilizes PYBASIS scripts developed by D.P. Grote, LLNL. The Python version also uses MPPL code and MAC Perl script, available from the public-domain BASIS source above. The Forthon version of UEDGE uses the same source files, but utilizes Forthon to produce a Python-compatible source. Forthon has been developed by D.P. Grote at LBL (see http://hifweb.lbl.gov/Forthon/ and Grote et al. in the references below), and it is freely available. The graphics can be performed by any package importable to Python, such as PYGIST.« less

  5. Long-term ambient concentrations of total suspended particulates and oxidants as related to incidence of chronic disease in California Seventh-Day Adventists.

    PubMed Central

    Abbey, D E; Mills, P K; Petersen, F F; Beeson, W L

    1991-01-01

    Cancer incidence and mortality in a cohort of 6000 nonsmoking California Seventh-Day Adventists were monitored for a 6-year period, and relationships with long-term cumulative ambient air pollution were observed. Total suspended particulates (TSP) and ozone were measured in terms of numbers of hours in excess of several threshold levels corresponding to national standards as well as mean concentration. For all malignant neoplasms among females, risk increased with increasing exceedance frequencies of all thresholds of TSP except the lowest one, and those increased risks were highly statistically significant. For respiratory cancers, increased risk was associated with only one threshold of ozone, and this result was of borderline significance. Respiratory disease symptoms were assessed in 1977 and again in 1987 using the National Heart, Lung and Blood Institute respiratory symptoms questionnaire on a subcohort of 3914 individuals. Multivariate analyses which adjusted for past and passive smoking and occupational exposures indicated statistically significantly (p less than 0.05) elevated relative risks ranging up to 1.7 for incidence of asthma, definite symptoms of airway obstructive disease, and chronic bronchitis with TSP in excess of all thresholds except the lowest one but not for any thresholds of ozone. A trend association (p = 0.056) was noted between the threshold of 10 pphm ozone and incidence of asthma. These results are presented within the context of standards setting for these constituents of air pollution. PMID:1954938

  6. Chronic obstructive pulmonary disease symptom effects of long-term cumulative exposure to ambient levels of total oxidants and nitrogen dioxide in California Seventh-Day Adventist residents

    SciTech Connect

    Euler, G.L.; Abbey, D.E.; Hodgkin, J.E.; Magie, A.R.

    1988-07-01

    To assess the risk of chronic obstructive pulmonary disease symptoms due to long-term exposure to ambient levels of total oxidants and nitrogen dioxide (NO2), symptoms were ascertained using the National Heart, Lung, and Blood Institute (NHLBI) respiratory symptoms questionnaire. A total of 7,445 Seventh-day Adventist (SDA) nonsmokers who were 25 yr of age or older and had resided at least 11 yr in areas of California with high to low photochemical air pollution were included in this study. Cumulative exposures to each pollutant in excess of four thresholds were estimated for each participant, using zip codes for months of residence and interpolated dosages from state air-monitoring stations. Multiple logistic regression analyses were conducted individually and together for pollutants and included eight covariables, including passive smoking. A statistically significant association with chronic symptoms was seen for total oxidants above 10 pphm (196 mcg/m3) (p less than .004, relative risk of 1.20 for 750 hr/yr). Chronic respiratory disease symptoms were not associated with relatively low NO2 exposure levels in this population. When these pollutant exposures were studied with exposures to total suspended particulates (TSP) and sulfur dioxide (SO2), only TSP exposure above 200 mcg/m3 showed statistical significance (p less than .01). Exposure to TSP is either more strongly associated with symptoms of chronic obstructive pulmonary disease than the other measured exposures or is the best single surrogate representing the mix of pollutants present.

  7. Long-term ambient concentrations of total suspended particulates and oxidants as related to incidence of chronic disease in California Seventh-Day Adventists

    SciTech Connect

    Abbey, D.E.; Mills, P.K.; Petersen, F.F.; Beeson, W.L. )

    1991-08-01

    Cancer incidence and mortality in a cohort of 6000 nonsmoking California Seventh-Day Adventists were monitored for a 6-year period, and relationships with long-term cumulative air pollution were observed. Total suspended particulates (TSP) and ozone were measured in terms of numbers of hours in excess of several threshold levels corresponding to national standards as well as mean concentration. For all malignant neoplasms among females, risk increased with increasing exceedance frequencies of all thresholds of TSP except the lowest one, and those increased risks were highly statistically significant. For respiratory cancers, increased risk was associated with only one threshold of ozone, and this result was of borderline significance. Respiratory disease symptoms were assessed in 1977 and again in 1987 using the National Heart, Lung and Blood Institute respiratory symptoms questionnaire on a subcohort of 3914 individuals. Multivariate analyses which adjusted for past and passive smoking and occupational exposures indicated statistically significantly elevated relative risks ranging up to 1.7 for incidence of asthma, definite symptoms of airway obstructive disease, and chronic bronchitis with TSP in excess of all thresholds except the lowest one but not for any thresholds of ozone. A trend association was noted between the threshold of 10 pphm ozone and incidence of asthma. These results are presented within the context of standards setting for these constituents of air pollution.

  8. The edges of graphene.

    PubMed

    Zhang, Xiuyun; Xin, John; Ding, Feng

    2013-04-01

    The edge of two dimensional (2D) graphene, as the surface of a three dimensional (3D) crystal, plays a crucial role in the determination of its physical, electronic and chemical properties and thus has been extensively studied recently. In this review, we summarize the recent advances in the study of graphene edges, including edge formation energy, edge reconstruction, method of graphene edge synthesis and the recent progress on metal-passivated graphene edges and the role of edges in graphene CVD growth. We expect this review to provide a guideline for readers to gain a clear picture of graphene edges from several aspects, especially the catalyst-passivated graphene edges and their role in graphene CVD growth.

  9. Measures of Heart Rate Variability and How They Relate to Age, Gender, Emotional Behavior, and Academic Achievement in Elementary School Children in Adventist and Public Schools

    ERIC Educational Resources Information Center

    Dalton, Marilee Serns

    2013-01-01

    The analysis of heart rate variability (HRV) is one tool shown to be of value in examining heart-brain interactions. HRV is remarkably responsive to emotion, and the importance of emotional state in cognitive function is increasingly being recognized and socio-emotional learning strategies being utilized in the classroom. Consequently, the…

  10. A River Runs through It: A School on the Edge of the Columbia River Estuary Combines Science and Stewardship Right in Its Own Backyard.

    ERIC Educational Resources Information Center

    Sherman, Lee

    2002-01-01

    The estuary at the mouth of the Columbia River in Wahkiakum County Washington) provides a natural laboratory for experiential learning. Wahkiakum High School students participate in interdisciplinary projects that have included habitat restoration, a salmon hatchery, stream restoration, tree planting, and recreating the final leg of the Lewis and…

  11. Speech and Language Therapy and the Knowles Edge Standards Fund Project: An Evaluation of the Service Provided to a Cluster of Primary Schools

    ERIC Educational Resources Information Center

    Roulstone, Sue; Owen, Rosalind; French, Lucy

    2005-01-01

    In 2000, 25 speech and language therapy projects were established in schools in England, funded through the Standards Fund. An evaluation commissioned by the Government reported positive results and gave an overview of all the projects at a point approximately six months after their inception. Although there were common themes, it was quite clear…

  12. The Association between Incident Self-reported Fibromyalgia and Non-psychiatric Factors: 25-years Follow-up of the Adventist Health Study

    PubMed Central

    Choi, Chan-Jin; Knutsen, Raymond; Oda, Keiji; Fraser, Gary E

    2010-01-01

    The purpose of the study was to investigate the association between incident self-reported fibromyalgia (FM) and prior somatic diseases, lifestyle factors and health behaviors among 3,136 women who participated in two cohort studies 25–26 years apart (the Adventist Health Study 1 and 2). The women completed a comprehensive lifestyle and medical history questionnaire at baseline in 1976. Information on new diagnosis of doctor-told FM was obtained at the 2nd survey in 2002. A total of 136 women reported a diagnosis of FM during 25 years of follow-up, giving a period incidence of 43/1,000 or 1.72/1000 per year. In multivariable logistic regression analyses, a significant, dose-response association was found with number of allergies with OR of 1.61 (95% CI:0.92–2.83) and 3.99 (95% CI:2.31–6.88), (p[trend]<0.0001, respectively, for 1 and 2 or more allergies versus none. A history of hyperemesis gravidarum was also associated with FM with OR of 1.32 (95% CI:0.75–2.32) and 1.73 (95% CI:0.99–3.03), (p[trend]<0.05), respectively, for some or all pregnancies versus none. A positive association with smoking was also found with OR of 2.37 (95% CI:1.33–4.23) for ever smokers versus never smokers. No significant association was found with number of surgeries, history of peptic ulcer or taking medications to control various symptoms. PMID:20400378

  13. Legumes and meat analogues consumption are associated with hip fracture risk independently of meat intake among Caucasian men and women: the Adventist Health Study-2

    PubMed Central

    Lousuebsakul-Matthews, Vichuda; Thorpe, Donna L; Knutsen, Raymond; Beeson, W Larry; Fraser, Gary E; Knutsen, Synnove F

    2014-01-01

    Objective In contrast to non-vegetarians, vegetarians consume more legumes and meat analogues as sources of protein to substitute for meat intake. The present study aimed to assess the association between foods with high protein content (legumes, meat, meat analogues) by dietary pattern (vegetarians, non-vegetarians) and hip fracture incidence, adjusted for selected lifestyle factors. Design A prospective cohort of Adventist Health Study-2 (AHS-2) enrollees who completed a comprehensive lifestyle and dietary questionnaire between 2002 and 2007. Setting Every two years after enrolment, a short questionnaire on hospitalizations and selected disease outcomes including hip fractures was sent to these members. Subjects Respondents (n 33 208) to a baseline and a follow-up questionnaire. Results In a multivariable model, legumes intake of once daily or more reduced the risk of hip fracture by 64% (hazard ratio=0·36, 95% CI 0·21, 0·61) compared with those with legumes intake of less than once weekly. Similarly, meat intake of four or more times weekly was associated with a 40% reduced risk of hip fracture (hazard ratio=0·60, 95% CI 0·41, 0·87) compared with those whose meat intake was less than once weekly. Furthermore, consumption of meat analogues once daily or more was associated with a 49% reduced risk of hip fracture (hazard ratio=0·51, 95% CI 0·27, 0·98) compared with an intake of less than once weekly. Conclusions Hip fracture incidence was inversely associated with legumes intake and, to a lesser extent, meat intake, after accounting for other food groups and important covariates. Similarly, a high intake of meat analogues was associated with a significantly reduced risk of hip fracture. PMID:24103482

  14. The Edge, Fall 1999.

    ERIC Educational Resources Information Center

    Edge, 1999

    1999-01-01

    "The Edge" is a Canadian publication for youth. The mandate of the Edge is to support and celebrate all career journeys embraced by youth. This issue contains career profile articles covering three jobs: crane operator, indoor climbing instructor, and product certification tester. Career trends and the state of today's workplace are also…

  15. Supersonic Leading Edge Receptivity

    NASA Technical Reports Server (NTRS)

    Maslov, Anatoly A.

    1998-01-01

    This paper describes experimental studies of leading edge boundary layer receptivity for imposed stream disturbances. Studies were conducted in the supersonic T-325 facility at ITAM and include data for both sharp and blunt leading edges. The data are in agreement with existing theory and should provide guidance for the development of more complete theories and numerical computations of this phenomena.

  16. Soy milk and dairy consumption is independently associated with ultrasound attenuation of the heel bone among postmenopausal women: the Adventist Health Study-2.

    PubMed

    Matthews, Vichuda Lousuebsakul; Knutsen, Synnove F; Beeson, W Lawrence; Fraser, Gary E

    2011-10-01

    Soy milk has become a popular substitute for dairy milk with important health claims. We hypothesized that soy milk, based on its nutrient composition, is comparable to dairy products and, therefore, beneficial for bone health. To test this hypothesis, we examined the benefit of soy milk and dairy products intake on bone health using broadband ultrasound attenuation of the calcaneus. Postmenopausal white women (n = 337) who had completed a lifestyle and dietary questionnaire at enrollment into the Adventist Health Study-2 had their calcaneal broadband ultrasound attenuation measured 2 years later. The association between osteoporosis (defined as a T-score <-1.8) and some dietary factors (soy milk, dairy) and selected lifestyle factors was assessed using logistic regression. In a multivariable model adjusted for demographics, hormone use, and other dietary factors, osteoporosis was positively associated with age (odds ratio [OR] = 1.08; 95% confidence interval [CI], 1.06-1.12) and inversely associated with body mass index (OR = 0.91; 95% CI, 0.86-0.97) and current estrogen use (OR = 0.27; 95% CI, 0.13-0.56). Compared with women who did not drink soy milk, women drinking soy milk once a day or more had 56% lower odds of osteoporosis (OR = 0.44; 95% CI, 0.20-0.98; P(trend) = .04). Women whose dairy intake was once a day or more had a 62% reduction in the likelihood of having osteoporosis (OR = 0.38; 95% CI, 0.17-0.86; P(trend) = .02) compared with women whose dairy intake was less than twice a week. Among individual dairy products, only cheese showed an independent and significant protection (OR = 0.28; 95% CI, 0.12-0.66; P(trend) = .004) for women eating cheese more than once per week vs those who ate cheese less than once a week. We concluded that osteoporosis is inversely associated with soy milk intake to a similar degree as dairy intake after accounting for age, body mass index, and estrogen use.

  17. The digital step edge

    NASA Technical Reports Server (NTRS)

    Haralick, R. M.

    1982-01-01

    The facet model was used to accomplish step edge detection. The essence of the facet model is that any analysis made on the basis of the pixel values in some neighborhood has its final authoritative interpretation relative to the underlying grey tone intensity surface of which the neighborhood pixel values are observed noisy samples. Pixels which are part of regions have simple grey tone intensity surfaces over their areas. Pixels which have an edge in them have complex grey tone intensity surfaces over their areas. Specially, an edge moves through a pixel only if there is some point in the pixel's area having a zero crossing of the second directional derivative taken in the direction of a non-zero gradient at the pixel's center. To determine whether or not a pixel should be marked as a step edge pixel, its underlying grey tone intensity surface was estimated on the basis of the pixels in its neighborhood.

  18. Cutting Edge Cable Management.

    ERIC Educational Resources Information Center

    Peach, Roger

    1997-01-01

    Describes how one school district was able to efficiently install fragile telecommunication cabling throughout its high school and save thousands of dollars. Discusses solutions to some common cable-management problems. (GR)

  19. The Edge supersonic transport

    NASA Technical Reports Server (NTRS)

    Agosta, Roxana; Bilbija, Dushan; Deutsch, Marc; Gallant, David; Rose, Don; Shreve, Gene; Smario, David; Suffredini, Brian

    1992-01-01

    As intercontinental business and tourism volumes continue their rapid expansion, the need to reduce travel times becomes increasingly acute. The Edge Supersonic Transport Aircraft is designed to meet this demand by the year 2015. With a maximum range of 5750 nm, a payload of 294 passengers and a cruising speed of M = 2.4, The Edge will cut current international flight durations in half, while maintaining competitive first class, business class, and economy class comfort levels. Moreover, this transport will render a minimal impact upon the environment, and will meet all Federal Aviation Administration Part 36, Stage III noise requirements. The cornerstone of The Edge's superior flight performance is its aerodynamically efficient, dual-configuration design incorporating variable-geometry wingtips. This arrangement combines the benefits of a high aspect ratio wing at takeoff and low cruising speeds with the high performance of an arrow-wing in supersonic cruise. And while the structural weight concerns relating to swinging wingtips are substantial, The Edge looks to ever-advancing material technologies to further increase its viability. Heeding well the lessons of the past, The Edge design holds economic feasibility as its primary focus. Therefore, in addition to its inherently superior aerodynamic performance, The Edge uses a lightweight, largely windowless configuration, relying on a synthetic vision system for outside viewing by both pilot and passengers. Additionally, a fly-by-light flight control system is incorporated to address aircraft supersonic cruise instability. The Edge will be produced at an estimated volume of 400 aircraft and will be offered to airlines in 2015 at $167 million per transport (1992 dollars).

  20. Extended Klein edges in graphene.

    PubMed

    He, Kuang; Robertson, Alex W; Lee, Sungwoo; Yoon, Euijoon; Lee, Gun-Do; Warner, Jamie H

    2014-12-23

    Graphene has three experimentally confirmed periodic edge terminations, zigzag, reconstructed 5-7, and arm-chair. Theory predicts a fourth periodic edge of graphene called the extended Klein (EK) edge, which consists of a series of single C atoms protruding from a zigzag edge. Here, we confirm the existence of EK edges in both graphene nanoribbons and on the edge of bulk graphene using atomic resolution imaging by aberration-corrected transmission electron microscopy. The formation of the EK edge stems from sputtering and reconstruction of the zigzag edge. Density functional theory reveals minimal energy for EK edge reconstruction and bond distortion both in and out of plane, supporting our TEM observations. The EK edge can now be included as the fourth member of observed periodic edge structures in graphene.

  1. Properties on the edge: graphene edge energies, edge stresses, edge warping, and the Wulff shape of graphene flakes

    NASA Astrophysics Data System (ADS)

    Branicio, Paulo S.; Jhon, Mark H.; Gan, Chee Kwan; Srolovitz, David J.

    2011-07-01

    It has been shown that the broken bonds of an unreconstructed graphene edge generate compressive edge stresses leading to edge warping. Here, we investigate edge energies and edge stresses of graphene nanoribbons with arbitrary orientations from armchair to zigzag, considering both flat and warped edge shapes in the presence and absence of hydrogen. We use the second generation reactive empirical bond order potential to calculate the edge energies and stresses for clean and hydrogenated edges. Using these energies, we perform a Wulff construction to determine the equilibrium shapes of flat graphene flakes as a function of hydrogen chemical potential. While edge stresses for clean, flat edges are compressive, they become tensile if allowed to warp. Conversely, we find that edge energies change little (~1%) with edge warping. Hydrogenation of the edges virtually eliminates both the edge energy and edge stresses. For warped edges an approximately linear relationship is found between amplitudes and wavelengths. The equilibrium shape of a graphene flake is determined by the value of the hydrogen chemical potential. For very small (and large) values of it the flakes have a nearly hexagonal (dodecagon) shape with zigzag oriented edges, while for intermediate values graphene flakes are found with complex shapes.

  2. High Speed Edge Detection

    NASA Technical Reports Server (NTRS)

    Prokop, Norman F (Inventor)

    2015-01-01

    Analog circuits for detecting edges in pixel arrays are disclosed. A comparator may be configured to receive an all pass signal and a low pass signal for a pixel intensity in an array of pixels. A latch may be configured to receive a counter signal and a latching signal from the comparator. The comparator may be configured to send the latching signal to the latch when the all pass signal is below the low pass signal minus an offset. The latch may be configured to hold a last negative edge location when the latching signal is received from the comparator.

  3. High Speed Edge Detection

    NASA Technical Reports Server (NTRS)

    Prokop, Norman F (Inventor)

    2016-01-01

    Analog circuits for detecting edges in pixel arrays are disclosed. A comparator may be configured to receive an all pass signal and a low pass signal for a pixel intensity in an array of pixels. A latch may be configured to receive a counter signal and a latching signal from the comparator. The comparator may be configured to send the latching signal to the latch when the all pass signal is below the low pass signal minus an offset. The latch may be configured to hold a last negative edge location when the latching signal is received from the comparator.

  4. Oscillating edge-flames

    NASA Astrophysics Data System (ADS)

    Buckmaster, J.; Zhang, Yi

    1999-09-01

    It has been known for some years that when a near-limit flame spreads over a liquid pool of fuel, the edge of the flame can oscillate. It is also known that when a near-asphyxiated candle-flame burns in zero gravity, the edge of the (hemispherical) flame can oscillate violently prior to extinction. We propose that these oscillations are nothing more than a manifestation of the large Lewis number instability well known in chemical reactor studies and in combustion studies, one that is exacerbated by heat losses. As evidence of this we examine an edge-flame confined within a fuel-supply boundary and an oxygen-supply boundary, anchored by a discontinuity in data at the fuel-supply boundary. We show that when the Lewis number of the fuel is 2, and the Lewis number of the oxidizer is 1, oscillations of the edge occur when the Damköhler number is reduced below a critical value. During a single oscillation period there is a short premixed propagation stage and a long diffusion stage, behaviour that has been observed in flame spread experiments. Oscillations do not occur when both Lewis numbers are equal to 1.

  5. Superpixel edges for boundary detection

    DOEpatents

    Moya, Mary M.; Koch, Mark W.

    2016-07-12

    Various embodiments presented herein relate to identifying one or more edges in a synthetic aperture radar (SAR) image comprising a plurality of superpixels. Superpixels sharing an edge (or boundary) can be identified and one or more properties of the shared superpixels can be compared to determine whether the superpixels form the same or two different features. Where the superpixels form the same feature the edge is identified as an internal edge. Where the superpixels form two different features, the edge is identified as an external edge. Based upon classification of the superpixels, the external edge can be further determined to form part of a roof, wall, etc. The superpixels can be formed from a speckle-reduced SAR image product formed from a registered stack of SAR images, which is further segmented into a plurality of superpixels. The edge identification process is applied to the SAR image comprising the superpixels and edges.

  6. Edge magnetoplasmons in graphene

    NASA Astrophysics Data System (ADS)

    Petković, Ivana; Williams, F. I. B.; Glattli, D. Christian

    2014-03-01

    We have observed propagation of edge magnetoplasmon (EMP) modes in graphene in the quantum Hall regime by performing picosecond time-of-flight measurements between narrow contacts on the perimeter of micrometric exfoliated graphene. We find the propagation to be chiral with low attenuation and to have a velocity which is quantized on Hall plateaus. The velocity has two contributions, one arising from the Hall conductivity and the other from carrier drift along the edge, which we were able to separate by their different filling factor dependence. The drift component is found to be slightly less than the Fermi velocity as expected for graphene dynamics in an abrupt edge potential. The Hall conduction contribution is slower than expected and indicates a characteristic length in the Coulomb potential from the Hall charge of about 500 nm. The experiment illustrates how EMP can be coupled to the electromagnetic field, opening the perspective of GHz to THz chiral plasmonics applications to devices such as voltage controlled phase shifters, circulators, switches and compact, tunable ring resonators.

  7. Electrochemistry of folded graphene edges.

    PubMed

    Ambrosi, Adriano; Bonanni, Alessandra; Pumera, Martin

    2011-05-01

    There is enormous interest in the investigation of electron transfer rates at the edges of graphene due to possible energy storage and sensing applications. While electrochemistry at the edges and the basal plane of graphene has been studied in the past, the new frontier is the electrochemistry of folded graphene edges. Here we describe the electrochemistry of folded graphene edges and compare it to that of open graphene edges. The materials were characterized in detail by high-resolution transmission electron microscopy, Raman spectroscopy, high-resolution X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy and cyclic voltammetry. We found that the heterogeneous electron transfer rate is significantly lower on folded graphene edges compared to open edge sites for ferro/ferricyanide, and that electrochemical properties of open edges offer lower potential detection of biomarkers than the folded ones. It is apparent, therefore, that for sensing and biosensing applications the folded edges are less active than open edges, which should then be preferred for such applications. As folded edges are the product of thermal treatment of multilayer graphene, such thermal procedures should be avoided when fabricating graphene for electrochemical applications.

  8. Chronic obstructive pulmonary disease symptom effects of long-term cumulative exposure to ambient levels of total suspended particulates and sulfur dioxide in California Seventh-Day Adventist residents

    SciTech Connect

    Euler, G.L.; Abbey, D.E.; Magie, A.R.; Hodgkin, J.E.

    1987-07-01

    Risk of chronic obstructive pulmonary disease symptoms due to long-term exposure to ambient levels of total suspended particulates (TSP) and sulfur dioxide (SO/sub 2/) symptoms was ascertained using the National Heart, Lung, and Blood Institute (NHLBI) respiratory symptoms questionnaire on 7445 Seventh-Day Adventists. They were non-smokers, at least 25 yr of age, and had lived 11 yr or more in areas ranging from high to low photochemical air pollution in California. Participant cumulative exposures to each pollutant in excess of four thresholds were estimated using monthly residence zip code histories and interpolated dosages from state air monitoring stations. These pollutant thresholds were entered individually and in combination in multiple logistic regression analyses with eight covariables including passive smoking. Statistically significant associations with chronic symptoms were seen for: SO/sub 2/ exposure above 4 pphm (104 mcg/m3), (p = .03), relative risk 1.18 for 500 hr/yr of exposure; and for total suspended particulates (TSP) above 200 mcg/m3, (p less than .00001), relative risk of 1.22 for 750 hr/yr.

  9. Cutting Edge EDU. @ USC.

    ERIC Educational Resources Information Center

    Mosher, Diana

    2000-01-01

    Discusses the principles and components of the University of Southern California's "smart building": the Marshall School of Business. The building's design, learning environment, use of high-tech learning tools, audio/video teleconferencing, and more than 1,100 data/power hookups, making it the most technologically advanced in the country, are…

  10. Charter Schools Uncovered

    ERIC Educational Resources Information Center

    Fowler-Finn, Thomas

    2008-01-01

    In this era of unforgiving accountability and test scores with high-stakes implications, important lessons can be learned from charter school marketing. Scrutiny of the regular public schools has never been more sharp-edged. Charter school proponents are becoming increasingly aggressive in promoting themselves as a viable alternative for…

  11. Edge remap for solids

    SciTech Connect

    Kamm, James R.; Love, Edward; Robinson, Allen C.; Young, Joseph G.; Ridzal, Denis

    2013-12-01

    We review the edge element formulation for describing the kinematics of hyperelastic solids. This approach is used to frame the problem of remapping the inverse deformation gradient for Arbitrary Lagrangian-Eulerian (ALE) simulations of solid dynamics. For hyperelastic materials, the stress state is completely determined by the deformation gradient, so remapping this quantity effectively updates the stress state of the material. A method, inspired by the constrained transport remap in electromagnetics, is reviewed, according to which the zero-curl constraint on the inverse deformation gradient is implicitly satisfied. Open issues related to the accuracy of this approach are identified. An optimization-based approach is implemented to enforce positivity of the determinant of the deformation gradient. The efficacy of this approach is illustrated with numerical examples.

  12. Edge-on!

    NASA Astrophysics Data System (ADS)

    2007-08-01

    Peering at Uranus's Rings as they Swing Edge-on to Earth for the First Time Since their Discovery in 1977 As Uranus coasts through a brief window of time when its rings are edge-on to Earth - a view of the planet we get only once every 42 years - astronomers peering at the rings with ESO's Very Large Telescope and other space or ground-based telescopes are getting an unprecedented view of the fine dust in the system, free from the glare of the bright rocky rings. They may even find a new moon or two. ESO PR Photo 37/07 ESO PR Photo 37/07 The Uranus System "ESO's VLT took data at the precise moment when the rings were edge-on to Earth," said Imke de Pater, of University of California, Berkeley who coordinated the worldwide campaign. She worked with two team members observing in Chile: Daphne Stam of the Technical University Delft in the Netherlands and Markus Hartung of ESO. The observations were done with NACO, one of the adaptive optics instruments installed at the VLT. With adaptive optics, it is possible to obtain images almost free from the blurring effect of the atmosphere. It is as if the 8.2-m telescope were observing from space. Observations were also done with the Keck telescope in Hawaii, the Hubble Space Telescope, and at the Palomar Observatory. "Using different telescopes around the world allows us to observe as much of the changes during the ring-plane crossing as possible: when Uranus sets as seen from the VLT, it can still be observed by the Keck," emphasised Stam. Uranus orbits the Sun in 84 years. Twice during a Uranian year, the rings appear edge-on to Earth for a brief period. The rings were discovered in 1977, so this is the first time for a Uranus ring-crossing to be observed from Earth. The advantage of observations at a ring-plane crossing is that it becomes possible to look at the rings from the shadowed or dark side. From that vantage point, the normally bright outer rings grow fainter because their centimetre- to metre-sized rocks obscure

  13. Edge phonons in black phosphorus

    NASA Astrophysics Data System (ADS)

    Ribeiro, H. B.; Villegas, C. E. P.; Bahamon, D. A.; Muraca, D.; Castro Neto, A. H.; de Souza, E. A. T.; Rocha, A. R.; Pimenta, M. A.; de Matos, C. J. S.

    2016-07-01

    Black phosphorus has recently emerged as a new layered crystal that, due to its peculiar and anisotropic crystalline and electronic band structures, may have important applications in electronics, optoelectronics and photonics. Despite the fact that the edges of layered crystals host a range of singular properties whose characterization and exploitation are of utmost importance for device development, the edges of black phosphorus remain poorly characterized. In this work, the atomic structure and behaviour of phonons near different black phosphorus edges are experimentally and theoretically studied using Raman spectroscopy and density functional theory calculations. Polarized Raman results show the appearance of new modes at the edges of the sample, and their spectra depend on the atomic structure of the edges (zigzag or armchair). Theoretical simulations confirm that the new modes are due to edge phonon states that are forbidden in the bulk, and originated from the lattice termination rearrangements.

  14. Edge phonons in black phosphorus.

    PubMed

    Ribeiro, H B; Villegas, C E P; Bahamon, D A; Muraca, D; Castro Neto, A H; de Souza, E A T; Rocha, A R; Pimenta, M A; de Matos, C J S

    2016-01-01

    Black phosphorus has recently emerged as a new layered crystal that, due to its peculiar and anisotropic crystalline and electronic band structures, may have important applications in electronics, optoelectronics and photonics. Despite the fact that the edges of layered crystals host a range of singular properties whose characterization and exploitation are of utmost importance for device development, the edges of black phosphorus remain poorly characterized. In this work, the atomic structure and behaviour of phonons near different black phosphorus edges are experimentally and theoretically studied using Raman spectroscopy and density functional theory calculations. Polarized Raman results show the appearance of new modes at the edges of the sample, and their spectra depend on the atomic structure of the edges (zigzag or armchair). Theoretical simulations confirm that the new modes are due to edge phonon states that are forbidden in the bulk, and originated from the lattice termination rearrangements. PMID:27412813

  15. Edge phonons in black phosphorus

    PubMed Central

    Ribeiro, H. B.; Villegas, C. E. P.; Bahamon, D. A.; Muraca, D.; Castro Neto, A. H.; de Souza, E. A. T.; Rocha, A. R.; Pimenta, M. A.; de Matos, C. J. S.

    2016-01-01

    Black phosphorus has recently emerged as a new layered crystal that, due to its peculiar and anisotropic crystalline and electronic band structures, may have important applications in electronics, optoelectronics and photonics. Despite the fact that the edges of layered crystals host a range of singular properties whose characterization and exploitation are of utmost importance for device development, the edges of black phosphorus remain poorly characterized. In this work, the atomic structure and behaviour of phonons near different black phosphorus edges are experimentally and theoretically studied using Raman spectroscopy and density functional theory calculations. Polarized Raman results show the appearance of new modes at the edges of the sample, and their spectra depend on the atomic structure of the edges (zigzag or armchair). Theoretical simulations confirm that the new modes are due to edge phonon states that are forbidden in the bulk, and originated from the lattice termination rearrangements. PMID:27412813

  16. Edge conduction in vacuum glazing

    SciTech Connect

    Simko, T.M.; Collins, R.E.; Beck, F.A.; Arasteh, D.

    1995-03-01

    Vacuum glazing is a form of low-conductance double glazing using in internal vacuum between the two glass sheets to eliminate heat transport by gas conduction and convection. An array of small support pillars separates the sheets; fused solder glass forms the edge seal. Heat transfer through the glazing occurs by radiation across the vacuum gap, conduction through the support pillars, and conduction through the bonded edge seal. Edge conduction is problematic because it affects stresses in the edge region, leading to possible failure of the glazing; in addition, excessive heat transfer because of thermal bridging in the edge region can lower overall window thermal performance and decrease resistance to condensation. Infrared thermography was used to analyze the thermal performance of prototype vacuum glazings, and, for comparison, atmospheric pressure superwindows. Research focused on mitigating the edge effects of vacuum glazings through the use of insulating trim, recessed edges, and framing materials. Experimentally validated finite-element and finite-difference modeling tools were used for thermal analysis of prototype vacuum glazing units and complete windows. Experimental measurements of edge conduction using infrared imaging were found to be in good agreement with finite-element modeling results for a given set of conditions. Finite-element modeling validates an analytic model developed for edge conduction.

  17. The Facilitator's Edge: Group Sessions for Edge-ucators.

    ERIC Educational Resources Information Center

    Handcock, Helen

    The Facilitator's Edge is a workshop series based on the life/work messages of The Edge magazine. The workshops are deigned to help educators, youth workers, and their career practitioners facilitate conscious career building. This manual consists of five group sessions, each focusing on a different career-building theme. "Megatrends and Making it…

  18. Edge-edge interactions in stacked graphene nanoplatelets

    SciTech Connect

    Cruz Silva, Eduardo; Terrones Maldonado, Humberto; Terrones Maldonado, Mauricio; Jia, Xiaoting; Sumpter, Bobby G; Dresselhaus, M; Meunier, V.

    2013-01-01

    High-resolution transmission electron microscopy (HRTEM) studies show the dynamics of small graphene platelets on larger graphene layers. The platelets move nearly freely to eventually lock in at well-defined positions close to the edges of the larger underlying graphene sheet. While such movement is driven by a shallow potential energy surface described by an interplane interaction, the lock-in position occurs by via edge-edge interactions of the platelet and the graphene surface located underneath. Here we quantitatively study this behavior using van der Waals density functional calculations. Local interactions at the open edges are found to dictate stacking configurations that are different from Bernal (AB) stacking. These stacking configurations are known to be otherwise absent in edge-free two-dimensional (2D) graphene. The results explain the experimentally observed platelet dynamics and provide a detailed account of the new electronic properties of these combined systems.

  19. Giant edge state splitting at atomically precise graphene zigzag edges

    PubMed Central

    Wang, Shiyong; Talirz, Leopold; Pignedoli, Carlo A.; Feng, Xinliang; Müllen, Klaus; Fasel, Roman; Ruffieux, Pascal

    2016-01-01

    Zigzag edges of graphene nanostructures host localized electronic states that are predicted to be spin-polarized. However, these edge states are highly susceptible to edge roughness and interaction with a supporting substrate, complicating the study of their intrinsic electronic and magnetic structure. Here, we focus on atomically precise graphene nanoribbons whose two short zigzag edges host exactly one localized electron each. Using the tip of a scanning tunnelling microscope, the graphene nanoribbons are transferred from the metallic growth substrate onto insulating islands of NaCl in order to decouple their electronic structure from the metal. The absence of charge transfer and hybridization with the substrate is confirmed by scanning tunnelling spectroscopy, which reveals a pair of occupied/unoccupied edge states. Their large energy splitting of 1.9 eV is in accordance with ab initio many-body perturbation theory calculations and reflects the dominant role of electron–electron interactions in these localized states. PMID:27181701

  20. Giant edge state splitting at atomically precise graphene zigzag edges.

    PubMed

    Wang, Shiyong; Talirz, Leopold; Pignedoli, Carlo A; Feng, Xinliang; Müllen, Klaus; Fasel, Roman; Ruffieux, Pascal

    2016-05-16

    Zigzag edges of graphene nanostructures host localized electronic states that are predicted to be spin-polarized. However, these edge states are highly susceptible to edge roughness and interaction with a supporting substrate, complicating the study of their intrinsic electronic and magnetic structure. Here, we focus on atomically precise graphene nanoribbons whose two short zigzag edges host exactly one localized electron each. Using the tip of a scanning tunnelling microscope, the graphene nanoribbons are transferred from the metallic growth substrate onto insulating islands of NaCl in order to decouple their electronic structure from the metal. The absence of charge transfer and hybridization with the substrate is confirmed by scanning tunnelling spectroscopy, which reveals a pair of occupied/unoccupied edge states. Their large energy splitting of 1.9 eV is in accordance with ab initio many-body perturbation theory calculations and reflects the dominant role of electron-electron interactions in these localized states.

  1. The Community College Baccalaureate Movement: Cutting-Edge Dissertation Research

    ERIC Educational Resources Information Center

    Hrabak, Michael R.

    2009-01-01

    In this review of dissertations, the researcher presents summaries of 10 of the most recent and cutting-edge dissertations focusing on the ever-growing and complex field of the community college baccalaureate movement. These studies focus on the gamut of specific legislation, case studies of particular programs and schools, financing of such…

  2. Living on the Future Edge: Windows on Tomorrow

    ERIC Educational Resources Information Center

    Jukes, Ian; McCain, Ted; Crockett, Lee

    2010-01-01

    "Living on the Future Edge" challenges school leaders to rethink longstanding paradigms and transform pedagogy for tomorrow's learners. Apple Computer, Inc. co-founder Steve Wozniak's foreword underscores the overwhelming need to adjust traditional instruction to fit today's high-tech world. The book explores this new landscape and offers a…

  3. Rock Segmentation through Edge Regrouping

    NASA Technical Reports Server (NTRS)

    Burl, Michael

    2008-01-01

    Rockster is an algorithm that automatically identifies the locations and boundaries of rocks imaged by the rover hazard cameras (hazcams), navigation cameras (navcams), or panoramic cameras (pancams). The software uses edge detection and edge regrouping to identify closed contours that separate the rocks from the background.

  4. Computer Methods in EDG Education.

    ERIC Educational Resources Information Center

    Mabrey, Robert L.

    1999-01-01

    Presents several computer-related techniques that encourage engineering design graphics (EDG) students to develop knowledge at levels 4 and 5 of Bloom's taxonomy. Contrasts this approach to extend the educational process with the development of training skills at knowledge levels 2 and 3, which are often the sole basis for EDG instruction.…

  5. The Robotic Edge Finishing Laboratory

    SciTech Connect

    Loucks, C.S.; Selleck, C.B.

    1990-08-01

    The Robotic Edge Finishing Laboratory at Sandia National Laboratories is developing four areas of technology required for automated deburring, chamfering, and blending of machined edges: (1) the automatic programming of robot trajectories and deburring processes using information derived from a CAD database, (2) the use of machine vision for locating the workpiece coupled with force control to ensure proper tool contact, (3) robotic deburring, blending, and machining of precision chamfered edges, and (4) in-process automated inspection of the formed edge. The Laboratory, its components, integration, and results from edge finishing experiments to date are described here. Also included is a discussion of the issues regarding implementation of the technology in a production environment. 24 refs., 17 figs.

  6. Edge-on Galaxy

    NASA Technical Reports Server (NTRS)

    1999-01-01

    NASA's Hubble Space Telescope has imaged an unusual edge-on galaxy, revealing remarkable details of its warped dusty disc and showing how colliding galaxies trigger the birth of new stars.

    The image, taken by Hubble's Wide Field and Planetary Camera 2 (WFPC2), is online at http://heritage.stsci.edu and http://www.jpl.nasa.gov/images/wfpc. The camera was designed and built by NASA's Jet Propulsion Laboratory, Pasadena, Calif. During observations of the galaxy, the camera passed a milestone, taking its 100,000th image since shuttle astronauts installed it in Hubble in 1993.

    The dust and spiral arms of normal spiral galaxies, like our Milky Way, look flat when seen edge- on. The new image of the galaxy ESO 510-G13 shows an unusual twisted disc structure, first seen in ground-based photographs taken at the European Southern Observatory in Chile. ESO 510-G13 lies in the southern constellation Hydra, some 150 million light-years from Earth. Details of the galaxy's structure are visible because interstellar dust clouds that trace its disc are silhouetted from behind by light from the galaxy's bright, smooth central bulge.

    The strong warping of the disc indicates that ESO 510-G13 has recently collided with a nearby galaxy and is in the process of swallowing it. Gravitational forces distort galaxies as their stars, gas, and dust merge over millions of years. When the disturbances die out, ESO 510-G13 will be a single galaxy.

    The galaxy's outer regions, especially on the right side of the image, show dark dust and bright clouds of blue stars. This indicates that hot, young stars are forming in the twisted disc. Astronomers believe star formation may be triggered when galaxies collide and their interstellar clouds are compressed.

    The Hubble Heritage Team used WFPC2 to observe ESO 510-G13 in April 2001. Pictures obtained through blue, green, and red filters were combined to make this color-composite image, which emphasizes the contrast between the dusty

  7. Theory of edge detection.

    PubMed

    Marr, D; Hildreth, E

    1980-02-29

    A theory of edge detection is presented. The analysis proceeds in two parts. (1) Intensity changes, which occur in a natural image over a wide range of scales, are detected separately at different scales. An appropriate filter for this purpose at a given scale is found to be the second derivative of a Gaussian, and it is shown that, provided some simple conditions are satisfied, these primary filters need not be orientation-dependent. Thus, intensity changes at a given scale are best detected by finding the zero values of delta 2G(x,y)*I(x,y) for image I, where G(x,y) is a two-dimensional Gaussian distribution and delta 2 is the Laplacian. The intensity changes thus discovered in each of the channels are then represented by oriented primitives called zero-crossing segments, and evidence is given that this representation is complete. (2) Intensity changes in images arise from surface discontinuities or from reflectance or illumination boundaries, and these all have the property that they are spatially. Because of this, the zero-crossing segments from the different channels are not independent, and rules are deduced for combining them into a description of the image. This description is called the raw primal sketch. The theory explains several basic psychophysical findings, and the operation of forming oriented zero-crossing segments from the output of centre-surround delta 2G filters acting on the image forms the basis for a physiological model of simple cells (see Marr & Ullman 1979).

  8. Hydrogen-free graphene edges

    NASA Astrophysics Data System (ADS)

    He, Kuang; Lee, Gun-Do; Robertson, Alex W.; Yoon, Euijoon; Warner, Jamie H.

    2014-01-01

    Graphene edges and their functionalization influence the electronic and magnetic properties of graphene nanoribbons. Theoretical calculations predict saturating graphene edges with hydrogen lower its energy and form a more stable structure. Despite the importance, experimental investigations of whether graphene edges are always hydrogen-terminated are limited. Here we study graphene edges produced by sputtering in vacuum and direct measurements of the C-C bond lengths at the edge show ~86% contraction relative to the bulk. Density functional theory reveals the contraction is attributed to the formation of a triple bond and the absence of hydrogen functionalization. Time-dependent images reveal temporary attachment of a single atom to the arm-chair C-C bond in a triangular configuration, causing expansion of the bond length, which then returns back to the contracted value once the extra atom moves on and the arm-chair edge is returned. Our results provide confirmation that non-functionalized graphene edges can exist in vacuum.

  9. Hydrogen-free graphene edges.

    PubMed

    He, Kuang; Lee, Gun-Do; Robertson, Alex W; Yoon, Euijoon; Warner, Jamie H

    2014-01-01

    Graphene edges and their functionalization influence the electronic and magnetic properties of graphene nanoribbons. Theoretical calculations predict saturating graphene edges with hydrogen lower its energy and form a more stable structure. Despite the importance, experimental investigations of whether graphene edges are always hydrogen-terminated are limited. Here we study graphene edges produced by sputtering in vacuum and direct measurements of the C-C bond lengths at the edge show ~86% contraction relative to the bulk. Density functional theory reveals the contraction is attributed to the formation of a triple bond and the absence of hydrogen functionalization. Time-dependent images reveal temporary attachment of a single atom to the arm-chair C-C bond in a triangular configuration, causing expansion of the bond length, which then returns back to the contracted value once the extra atom moves on and the arm-chair edge is returned. Our results provide confirmation that non-functionalized graphene edges can exist in vacuum.

  10. Reduction of airfoil trailing edge noise by trailing edge blowing

    NASA Astrophysics Data System (ADS)

    Gerhard, T.; Erbslöh, S.; Carolus, T.

    2014-06-01

    The paper deals with airfoil trailing edge noise and its reduction by trailing edge blowing. A Somers S834 airfoil section which originally was designed for small wind turbines is investigated. To mimic realistic Reynolds numbers the boundary layer is tripped on pressure and suction side. The chordwise position of the blowing slot is varied. The acoustic sources, i.e. the unsteady flow quantities in the turbulent boundary layer in the vicinity of the trailing edge, are quantified for the airfoil without and with trailing edge blowing by means of a large eddy simulation and complementary measurements. Eventually the far field airfoil noise is measured by a two-microphone filtering and correlation and a 40 microphone array technique. Both, LES-prediction and measurements showed that a suitable blowing jet on the airfoil suction side is able to reduce significantly the turbulence intensity and the induced surface pressure fluctuations in the trailing edge region. As a consequence, trailing edge noise associated with a spectral hump around 500 Hz could be reduced by 3 dB. For that a jet velocity of 50% of the free field velocity was sufficient. The most favourable slot position was at 90% chord length.

  11. Fast tracking using edge histograms

    NASA Astrophysics Data System (ADS)

    Rokita, Przemyslaw

    1997-04-01

    This paper proposes a new algorithm for tracking objects and objects boundaries. This algorithm was developed and applied in a system used for compositing computer generated images and real world video sequences, but can be applied in general in all tracking systems where accuracy and high processing speed are required. The algorithm is based on analysis of histograms obtained by summing along chosen axles pixels of edge segmented images. Edge segmentation is done by spatial convolution using gradient operator. The advantage of such an approach is that it can be performed in real-time using available on the market hardware convolution filters. After edge extraction and histograms computation, respective positions of maximums in edge intensity histograms, in current and previous frame, are compared and matched. Obtained this way information about displacement of histograms maximums, can be directly converted into information about changes of target boundaries positions along chosen axles.

  12. Edge equilibrium code for tokamaks

    SciTech Connect

    Li, Xujing; Drozdov, Vladimir V.

    2014-01-15

    The edge equilibrium code (EEC) described in this paper is developed for simulations of the near edge plasma using the finite element method. It solves the Grad-Shafranov equation in toroidal coordinate and uses adaptive grids aligned with magnetic field lines. Hermite finite elements are chosen for the numerical scheme. A fast Newton scheme which is the same as implemented in the equilibrium and stability code (ESC) is applied here to adjust the grids.

  13. Edge instabilities of topological superconductors

    NASA Astrophysics Data System (ADS)

    Hofmann, Johannes S.; Assaad, Fakher F.; Schnyder, Andreas P.

    2016-05-01

    Nodal topological superconductors display zero-energy Majorana flat bands at generic edges. The flatness of these edge bands, which is protected by time-reversal and translation symmetry, gives rise to an extensive ground-state degeneracy. Therefore, even arbitrarily weak interactions lead to an instability of the flat-band edge states towards time-reversal and translation-symmetry-broken phases, which lift the ground-state degeneracy. We examine the instabilities of the flat-band edge states of dx y-wave superconductors by performing a mean-field analysis in the Majorana basis of the edge states. The leading instabilities are Majorana mass terms, which correspond to coherent superpositions of particle-particle and particle-hole channels in the fermionic language. We find that attractive interactions induce three different mass terms. One is a coherent superposition of imaginary s -wave pairing and current order, and another combines a charge-density-wave and finite-momentum singlet pairing. Repulsive interactions, on the other hand, lead to ferromagnetism together with spin-triplet pairing at the edge. Our quantum Monte Carlo simulations confirm these findings and demonstrate that these instabilities occur even in the presence of strong quantum fluctuations. We discuss the implications of our results for experiments on cuprate high-temperature superconductors.

  14. Edge of polar cap patches

    NASA Astrophysics Data System (ADS)

    Hosokawa, K.; Taguchi, S.; Ogawa, Y.

    2016-04-01

    On the night of 4 December 2013, a sequence of polar cap patches was captured by an all-sky airglow imager (ASI) in Longyearbyen, Norway (78.1°N, 15.5°E). The 630.0 nm airglow images from the ASI of 4 second exposure time, oversampled the emission of natural lifetime (with quenching) of at least ˜30 sec, introduce no observational blurring effects. By using such high-quality ASI images, we succeeded in visualizing an asymmetry in the gradients between the leading/trailing edges of the patches in a 2-D fashion. The gradient in the leading edge was found to be 2-3 times steeper than that in the trailing edge. We also identified fingerlike structures, appearing only along the trailing edge of the patches, whose horizontal scale size ranged from 55 to 210 km. These fingers are considered to be manifestations of plasma structuring through the gradient-drift instability (GDI), which is known to occur only along the trailing edge of patches. That is, the current 2-D observations visualized, for the first time, how GDI stirs the patch plasma and such a mixing process makes the trailing edge more gradual. This result strongly implies a close connection between the GDI-driven plasma stirring and the asymmetry in the large-scale shape of patches and then suggests that the fingerlike structures can be used as markers to estimate the fine-scale structure in the plasma flow within patches.

  15. "Tinkering" Close to the Edge

    ERIC Educational Resources Information Center

    Mercurio, Mia Lynn; Morse, Charles R. A.

    2007-01-01

    In Harper v. Poway Community Unified School District, the Ninth Circuit Court ruled that a student could not wear a T-shirt to school bearing a statement that homosexual behavior is shameful. The court did not use the usual rationale, that such speech could disrupt school activities, but instead relied on the notion that such statements could…

  16. Flap-Edge Blowing Experiments

    NASA Technical Reports Server (NTRS)

    Gaeta, R. J.; Englar, R. J.; Ahuja, K. K.

    2003-01-01

    This Appendix documents the salient results from an effort to mitigate the so-called flap-edge noise generated at the split between a flap edge that is deployed and the undeployed flap. Utilizing a Coanda surface installed at the flap edge, steady blowing was used in an attempt to diminish the vortex strength resulting from the uneven lift distribution. The strength of this lifting vortex was augmented by steady blowing over the deployed flap. The test article for this study was the same 2D airfoil used in the steady blowing program reported earlier (also used in pulsed blowing tests, see Appendix G), however its trailing edge geometry was modified. An exact duplicate of the airfoil shape was made out of fiberglass with no flap, and in the clean configuration. It was attached to the existing airfoil to make an airfoil that has half of its flap deployed and half un-deployed. Figure 1 shows a schematic of the planform showing the two areas where steady blowing was introduced. The flap-edge blowing or the auxiliary blowing was in the direction normal to the freestream velocity vector. Slot heights for the blowing chambers were on the order of 0.0 14 inches.

  17. Edge-Aware BMA Filters.

    PubMed

    Guang Deng

    2016-01-01

    There has been continuous research in edge-aware filters which have found many applications in computer vision and image processing. In this paper, we propose a principled-approach for the development of edge-aware filters. The proposed approach is based on two well-established principles: 1) optimal parameter estimation and 2) Bayesian model averaging (BMA). Using this approach, we formulate the problem of filtering a pixel in a local pixel patch as an optimal estimation problem. Since a pixel belongs to multiple local patches, there are multiple estimates of the same pixel. We combine these estimates into a final estimate using BMA. We demonstrate the versatility of this approach by developing a family of BMA filters based on different settings of cost functions and log-likelihood and log-prior functions. We also present a new interpretation of the guided filter and develop a BMA guided filter which includes the guided filter as a special case. We show that BMA filters can produce similar smoothing results as those of the state-of-the-art edge-aware filters. Two BMA filters are computationally as efficient as the guided filter which is one of the fastest edge-aware filters. We also demonstrate that the BMA guided filter is better than the guided filter in preserving sharp edges. A new feature of the BMA guided filter is that the filtered image is similar to that produced by a clustering process.

  18. Image recovery from edge primitives

    NASA Technical Reports Server (NTRS)

    Alter-Gartenberg, Rachel; Huck, Friedrich O.; Narayanswamy, Ramkumar

    1990-01-01

    A method for extracting edge primitives from Mach-band patterns is presented together with a method for recovering image representations of features outlined by the edge boundaries. The accuracy, stability, and resolution of these representations are assessed. Since these representations are most commonly used in characterizing targets, this method of low-level processing offers new opportunities for computer vision and high data-compressing coding. Two bandpass filters are considered, the spatially invariant Laplacian of Gaussian filter and spatially variant intensity-dependent spatial (IDS) summation. It is shown that the recovery from the IDS bandpass data is particularly advantageous in applications for which robustness to local and temporal variations in illumination is important. It is concluded that the edge primitives extracted from bandpassed images can be an efficient way to store, transmit, and represent images.

  19. Wait for the Bus: How Lowcountry School Site Selection and Design Deter Walking to School and Contribute to Urban Sprawl.

    ERIC Educational Resources Information Center

    Kouri, Christopher

    This paper presents a study on how the South Carolina school site selection process can affect the quality of the students' experience and access to their schools. Focusing on students options for getting to school, e.g., hazards that prevent students from walking to school and the size of school sites that place schools on the edge of…

  20. Linking the "Leaky Edges" of the Outside with the Individual Inside

    ERIC Educational Resources Information Center

    Carlson, David Lee

    2007-01-01

    Throughout seven years of teaching in urban schools, the author discovered that the most effective ways to teach difficult literary texts was to refer to students' out-of-school activities. In other words, to connect the "leaky edges of the "social outside"" with the "individual inside" is to create a curriculum of "embodied relationships." This…

  1. Edge shape and comfort of rigid lenses.

    PubMed

    La Hood, D

    1988-08-01

    One of the main factors determining the comfort of a rigid contact lens is the shape of the edge. The comfort of four different contact lens edge shapes was assessed with four unadapted subjects in a randomized masked trial. Lenses with well rounded anterior edge profiles were found to be significantly more comfortable than lenses with square anterior edges. There was no significant difference in subjective comfort between a rounded and square posterior edge profile. The results suggest that the interaction of the edge with the eyelid is more important in determining comfort than edge effects on the cornea, when lenses are fitted according to a corneal alignment philosophy. PMID:3177585

  2. Shape-dependent canny edge detector

    NASA Astrophysics Data System (ADS)

    Panetta, Karen A.; Agaian, Sos S.; Nercessian, Shahan C.; Almunstashri, Ali A.

    2011-08-01

    Edges characterize the boundaries of objects in images and are informative structural cues for computer vision and target/object detection and recognition systems. The Canny edge detector is widely regarded as the edge detection standard. It is fairly adaptable to different environments, as its parametric nature attempts to tailor the detection of edges based on image-dependent characteristics or the particular requirements of a given implementation. Though it has been used in a myriad of image processing tasks, the Canny edge detector is still vulnerable to edge losses, localization errors, and noise sensitivity. These issues are largely due to the key tradeoff made in the scale and size of the edge detection filters used by the algorithm. Small-scaled filters are sensitive to edges but also to noise, whereas large-scaled filters are robust to noise but could filter out fine details. In this paper, novel edge detection kernel generalizations and a shape-dependent edge detector are introduced to alleviate these shortcomings. While most standard edge detection algorithms are based on convolving the input image with fixed size square kernels, this paper will illustrate the benefits of different filter sizes, and more importantly, different kernel shapes for edge detection. Moreover, new edge fusion methods are introduced to more effectively combine the individual edge responses. Existing edge detectors, including the Canny edge detector, can be obtained from the generalized edge detector by specifying corresponding parameters and kernel shapes. The proposed representations and edge detector have been qualitatively and quantitatively evaluated on several different types of image data. Computer simulations demonstrate that nonsquare kernel approaches can outperform square kernel approaches such as Canny, Sobel, Prewitt, Roberts, and others, providing better tradeoffs between noise rejection, accurate edge localization, and resolution. Where possible, Pratt's figure of

  3. Development of edge effects around experimental ecosystem hotspots is affected by edge density and matrix type

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ecological edge effects are sensitive to landscape context. In particular, edge effects can be altered by matrix type and by the presence of other nearby edges. We experimentally altered patch configurations in an African savanna to determine how edge density and matrix type influence edge effect de...

  4. Edge absorption and circular photogalvanic effect in 2D topological insulator edges

    NASA Astrophysics Data System (ADS)

    Entin, M. V.; Magarill, L. I.

    2016-06-01

    The electron absorption on the edge states and the edge photocurrent of a 2D topological insulator (TI) are studied. We consider the optical transitions within linear edge branches of the energy spectrum. The interaction with impurities is taken into account. The circular polarization is found to produce the edge photocurrent, the direction of which is determined by light polarization and edge orientation.

  5. Saddle-node dynamics for edge detection

    SciTech Connect

    Wong, Y.F.

    1994-09-01

    The author demonstrates how the formulation of a nonlinear scale-space filter can be used for edge detection and junction analysis. By casting edge-preserving filtering in terms of maximizing information content subject to an average cost function, the computed cost at each pixel location becomes a local measure of edgeness. This computation depends on a single scale parameter and the given image data. Unlike previous approaches which require careful tuning of the filter kernels for various types of edges, this scheme is general enough to be able to handle different edges, such as lines, step edges, corners and junctions. Anisotropy in the data is handled automatically by the nonlinear dynamics.

  6. Edge-on thick discs

    NASA Astrophysics Data System (ADS)

    Kasparova, A.; Katkov, I.; Chilingarian, I.; Silchenko, O.; Moiseev, A.; Borisov, S.

    2016-06-01

    Although thick stellar discs are detected in nearly all edge-on disc galaxies, their formation scenarios still remain a matter of debate. Due to observational difficulties, there is a lack of information about their stellar populations. Using the Russian 6-m telescope BTA we collected deep spectra of thick discs in three edge-on early-type disc galaxies located in different environments: NGC4111 in a dense group, NGC4710 in the Virgo cluster, and NGC5422 in a sparse group. We see intermediate age (4 ‑ 5 Gyr) metal rich ([Fe/H] ~ ‑0.2 ‑ 0.0 dex) stellar populations in NGC4111 and NGC4710. On the other hand, NGC5422 does not harbour young stars, its only disc is thick and old (10 Gyr) and its α-element abundance suggests a long formation epoch implying its formation at high redshift. Our results prove the diversity of thick disc formation scenarios.

  7. Linear array optical edge sensor

    NASA Technical Reports Server (NTRS)

    Bejczy, Antal K. (Inventor); Primus, Howard C. (Inventor)

    1987-01-01

    A series of independent parallel pairs of light emitting and detecting diodes for a linear pixel array, which is laterally positioned over an edge-like discontinuity in a workpiece to be scanned, is disclosed. These independent pairs of light emitters and detectors sense along intersecting pairs of separate optical axes. A discontinuity, such as an edge in the sensed workpiece, reflects a detectable difference in the amount of light from that discontinuity in comparison to the amount of light that is reflected on either side of the discontinuity. A sequentially sychronized clamping and sampling circuit detects that difference as an electrical signal which is recovered by circuitry that exhibits an improved signal-to-noise capability for the system.

  8. Gyrosheath near the tokamak edge

    SciTech Connect

    Hazeltine, R.D.; Xiao, H. . Inst. for Fusion Studies); Valanju, P.M. . Fusion Research Center)

    1993-03-01

    A new model for the structure of the radial electric field profile in the edge during the H-mode is proposed. Charge separation caused by the difference between electron and ion gyromotion, or more importantly in a tokamak, the banana motion (halo effect) can self-consistently produce an electric dipole moment that causes the sheared radial electric field. The calculated results based on the model are consistent with D-III D and TEXTOR experimental results.

  9. Edge-driven microplate kinematics

    USGS Publications Warehouse

    Schouten, Hans; Klitgord, Kim D.; Gallo, David G.

    1993-01-01

    It is known from plate tectonic reconstructions that oceanic microplates undergo rapid rotation about a vertical axis and that the instantaneous rotation axes describing the microplate's motion relative to the bounding major plates are frequently located close to its margins with those plates, close to the tips of propagating rifts. We propose a class of edge-driven block models to illustrate how slip across the microplate margins, block rotation, and propagation of rifting may be related to the relative motion of the plates on either side. An important feature of these edge-driven models is that the instantaneous rotation axes are always located on the margins between block and two bounding plates. According to those models the pseudofaults or traces of disrupted seafloor resulting from the propagation of rifting between microplate and major plates may be used independently to approximately trace the continuous kinematic evolution of the microplate back in time. Pseudofault geometries and matching rotations of the Easter microplate show that for most of its 5 m.y. history, block rotation could be driven by the drag of the Nazca and Pacific plates on the microplate's edges rather than by a shear flow of mantle underneath.

  10. Chemistry at the Edge of Graphene.

    PubMed

    Bellunato, Amedeo; Arjmandi Tash, Hadi; Cesa, Yanina; Schneider, Grégory F

    2016-03-16

    The selective functionalization of graphene edges is driven by the chemical reactivity of its carbon atoms. The chemical reactivity of an edge, as an interruption of the honeycomb lattice of graphene, differs from the relative inertness of the basal plane. In fact, the unsaturation of the pz orbitals and the break of the π conjugation on an edge increase the energy of the electrons at the edge sites, leading to specific chemical reactivity and electronic properties. Given the relevance of the chemistry at the edges in many aspects of graphene, the present Review investigates the processes and mechanisms that drive the chemical functionalization of graphene at the edges. Emphasis is given to the selective chemical functionalization of graphene edges from theoretical and experimental perspectives, with a particular focus on the characterization tools available to investigate the chemistry of graphene at the edge.

  11. Edge localized mode control with an edge resonant magnetic perturbation

    SciTech Connect

    Moyer, R.A.; Boedo, J.A.; Rudakov, D.L.; Evans, T.E.; Osborne, T.H.; Gohil, P.; Groebner, R.J.; Jackson, G.L.; La Haye, R.J.; Leonard, A.W.; Schaffer, M.J.; Snyder, P.B.; West, W.P.; Thomas, P.R.; Becoulet, M.; Harris, J.; Finken, K.-H.; Doyle, E.J.; Rhodes, T.L.; Wang, G.

    2005-05-15

    A low amplitude ({delta}b{sub r}/B{sub T}=1 part in 5000) edge resonant magnetic field perturbation with toroidal mode number n=3 and poloidal mode numbers between 8 and 15 has been used to suppress most large type I edge localized modes (ELMs) without degrading core plasma confinement. ELMs have been suppressed for periods of up to 8.6 energy confinement times when the edge safety factor q{sub 95} is between 3.5 and 4. The large ELMs are replaced by packets of events (possibly type II ELMs) with small amplitude, narrow radial extent, and a higher level of magnetic field and density fluctuations, creating a duty cycle with long 'active' intervals of high transport and short 'quiet' intervals of low transport. The increased transport associated with these events is less impulsive and slows the recovery of the pedestal profiles to the values reached just before the large ELMs without the n=3 perturbation. Changing the toroidal phase of the perturbation by 60 deg. with respect to the best ELM suppression case reduces the ELM amplitude and frequency by factors of 2-3 in the divertor, produces a more stochastic response in the H-mode pedestal profiles, and displays similar increases in small scale events, although significant numbers of large ELMs survive. In contrast to the best ELM suppression case where the type I ELMs are also suppressed on the outboard midplane, the midplane recycling increases until individual ELMs are no longer discernable. The ELM response depends on the toroidal phase of the applied perturbation because intrinsic error fields make the target plasma nonaxisymmetric, and suggests that at least some of the variation in ELM behavior in a single device or among different devices is due to differences in the intrinsic error fields in these devices. These results indicate that ELMs can be suppressed by small edge resonant magnetic field perturbations. Extrapolation to next-step burning plasma devices will require extending the regime of operation to

  12. Densified edge seals for fuel cell components

    DOEpatents

    DeCasperis, Anthony J.; Roethlein, Richard J.; Breault, Richard D.

    1982-01-01

    A porous fuel cell component, such as an electrode substrate, has a densified edge which forms an improved gas seal during operation when soaked with electrolyte. The edges are made from the same composition as the rest of the component and are made by compressing an increased thickness of this material along the edges during the fabrication process.

  13. Recruiting first generation college students into the Geosciences: Alaska's EDGE project

    NASA Astrophysics Data System (ADS)

    Prakash, A.; Connor, C.

    2008-12-01

    Funded in 2005-2008, by the National Science Foundation's Geoscience Education Division, the Experiential Discoveries in Geoscience Education (EDGE) project was designed to use glacier and watershed field experiences as venues for geospatial data collected by Alaska's grade 6-12 middle and high school teachers and their students. EDGE participants were trained in GIS and learned to analyze geospatial data to answer questions about the warming Alaska environment and to determine rates of ongoing glacier recession. Important emphasis of the program was the recruitment of Alaska Native students of Inupiat, Yup'ik, Athabascan, and Tlingit populations, living in both rural and urban areas around the state. Twelve of Alaska's 55 school districts have participated in the EDGE program. To engage EDGE students in the practice of scientific inquiry, each was required to carry out a semester scale research project using georeferenced data, guided by their EDGE teacher and mentor. Across Alaska students investigated several Earth systems processes including freezing conditions of lake ice; the changes in water quality in storm drains after rainfall events; movements of moose, bears, and bison across Alaskan landscapes; changes in permafrost depth in western Alaska; and the response of migrating waterfowl to these permafrost changes. Students correlated the substrate beneath their schools with known earthquake intensities; measured cutbank and coastal erosion on northern rivers and southeastern shorelines; tracked salmon infiltration of flooded logging roads; noted the changing behavior of eagles during late winter salmon runs; located good areas for the use of tidal power for energy production; tracked the extent and range of invasive plant species with warming; and the change of forests following deglaciation. Each cohort of EDGE students and teachers finished the program by attended a 3-day EDGE symposium at which students presented their research projects first in a

  14. K-edge densitometer (KED)

    SciTech Connect

    Sprinkle, J.K.; Hansen, W.J.

    1993-02-11

    In 1979, a K-edge densitometer (KED) was installed by the Safeguards Assay group from Los Alamos National Laboratory in the PNC reprocessing plant at Tokai-mura, Japan. It uses an active nondestructive assay technique, KED, to measure the plutonium concentration of the product solution. The measurement uncertainty of an assay depends on the count time chosen, but can be 0.5% or better. The computer hardware and software were upgraded in 1992. This manual describes the operation of the instrument, with an emphasis on the user interface to the software.

  15. An Efficient Ant-Based Edge Detector

    NASA Astrophysics Data System (ADS)

    Aydın, Doğan

    An efficient ant-based edge detector is presented. It is based on the distribution of ants on an image, ants try to find possible edges by using a state transition function based on 5x5 edge structures. Visual comparisons show that the proposed method gives finer details and thinner edges at lesser computational times when compared to earlier ant-based approaches. When compared to standard edge detectors, it shows robustness to Gaussian and Salt & Pepper noise and provides finer details than others with same parameter set in both clear and noisy images.

  16. Tunable skewed edges in puckered structures

    NASA Astrophysics Data System (ADS)

    Grujić, Marko M.; Ezawa, Motohiko; Tadić, Milan Ž.; Peeters, François M.

    2016-06-01

    We propose a type of edges arising due to the anisotropy inherent in the puckered structure of a honeycomb system such as in phosphorene. Skewed-zigzag and skewed-armchair nanoribbons are semiconducting and metallic, respectively, in contrast to their normal edge counterparts. Their band structures are tunable, and a metal-insulator transition is induced by an electric field. We predict a field-effect transistor based on the edge states in skewed-armchair nanoribbons, where the edge state is gapped by applying arbitrary small electric field Ez. A topological argument is presented, revealing the condition for the emergence of such edge states.

  17. Optimal edge filters explain human blur detection.

    PubMed

    McIlhagga, William H; May, Keith A

    2012-01-01

    Edges are important visual features, providing many cues to the three-dimensional structure of the world. One of these cues is edge blur. Sharp edges tend to be caused by object boundaries, while blurred edges indicate shadows, surface curvature, or defocus due to relative depth. Edge blur also drives accommodation and may be implicated in the correct development of the eye's optical power. Here we use classification image techniques to reveal the mechanisms underlying blur detection in human vision. Observers were shown a sharp and a blurred edge in white noise and had to identify the blurred edge. The resultant smoothed classification image derived from these experiments was similar to a derivative of a Gaussian filter. We also fitted a number of edge detection models (MIRAGE, N(1), and N(3)(+)) and the ideal observer to observer responses, but none performed as well as the classification image. However, observer responses were well fitted by a recently developed optimal edge detector model, coupled with a Bayesian prior on the expected blurs in the stimulus. This model outperformed the classification image when performance was measured by the Akaike Information Criterion. This result strongly suggests that humans use optimal edge detection filters to detect edges and encode their blur. PMID:22984222

  18. Measuring edge importance to improve immunization performance

    NASA Astrophysics Data System (ADS)

    Huang, He; Yan, Zhijun; Pan, Yaohui

    2014-12-01

    The edge heterogeneity has a remarkable influence on disease spreading, but it has seldom been considered in the disease-controlling policies. Based on the gravity model, we propose the edge importance index to describe the influence of edge heterogeneity on immunization strategies. Then the edge importance and contact weight are combined to calculate the infection rates on the I-S (Infected-Susceptible) edges in the complex network, and the difference of the infection rates on strong and weak ties is analyzed. Simulation results show that edge heterogeneity has a significant influence on the performance of immunization strategies, and better immunization efficiency is derived when the vaccination rate of the nodes in the weak I-S edges is increased.

  19. Haptic Edge Detection Through Shear

    PubMed Central

    Platkiewicz, Jonathan; Lipson, Hod; Hayward, Vincent

    2016-01-01

    Most tactile sensors are based on the assumption that touch depends on measuring pressure. However, the pressure distribution at the surface of a tactile sensor cannot be acquired directly and must be inferred from the deformation field induced by the touched object in the sensor medium. Currently, there is no consensus as to which components of strain are most informative for tactile sensing. Here, we propose that shape-related tactile information is more suitably recovered from shear strain than normal strain. Based on a contact mechanics analysis, we demonstrate that the elastic behavior of a haptic probe provides a robust edge detection mechanism when shear strain is sensed. We used a jamming-based robot gripper as a tactile sensor to empirically validate that shear strain processing gives accurate edge information that is invariant to changes in pressure, as predicted by the contact mechanics study. This result has implications for the design of effective tactile sensors as well as for the understanding of the early somatosensory processing in mammals. PMID:27009331

  20. Haptic Edge Detection Through Shear.

    PubMed

    Platkiewicz, Jonathan; Lipson, Hod; Hayward, Vincent

    2016-01-01

    Most tactile sensors are based on the assumption that touch depends on measuring pressure. However, the pressure distribution at the surface of a tactile sensor cannot be acquired directly and must be inferred from the deformation field induced by the touched object in the sensor medium. Currently, there is no consensus as to which components of strain are most informative for tactile sensing. Here, we propose that shape-related tactile information is more suitably recovered from shear strain than normal strain. Based on a contact mechanics analysis, we demonstrate that the elastic behavior of a haptic probe provides a robust edge detection mechanism when shear strain is sensed. We used a jamming-based robot gripper as a tactile sensor to empirically validate that shear strain processing gives accurate edge information that is invariant to changes in pressure, as predicted by the contact mechanics study. This result has implications for the design of effective tactile sensors as well as for the understanding of the early somatosensory processing in mammals. PMID:27009331

  1. Alternative Education: The Cutting Edge?

    ERIC Educational Resources Information Center

    Byrne, Jay

    2004-01-01

    Miami Valley Career Technology Youth Connections, an alternative high school located in Dayton, Ohio, has an enrollment of 160 students and was created as a joint venture among local politicians to address the high dropout rates in Montgomery County, Ohio. To achieve this, the Montgomery County commissioners created a task force to develop…

  2. Fusion Of Edge Maps In Color Images

    NASA Astrophysics Data System (ADS)

    Delcroix, C. J.; Abidi, M. A.

    1988-10-01

    In this paper, a new analytic method for the detection, of edges in color images is presented. This method focuses on the integration of three edge maps in order to increase one's confidence about the presence/absence of edges in a depicted scene. The integration process utilizes an algorithm developed by the authors under a broader research topic: The integration of registered multisensory data. It is based on the interaction between the following two constraints: the principle of existence, which tends to maximize the value of the output edge map at a given location if one input edge map features an edge, and the principle of confirmability, which adjusts this value according to the edge contents in the other input edge map at the same location by maximiz-ing the similarity between them. The latter two maximizations are achieved using the Euler-Language Calculus of Variations equations. This algorithm, which fuses optimally two correlated edge maps with regard to the above principles is extended to the simultaneous fusion of three edge maps. Experiments were conducted using not only the red, green, and blue representation of color information but also other bases.

  3. Edge detection in microscopy images using curvelets

    PubMed Central

    Gebäck, Tobias; Koumoutsakos, Petros

    2009-01-01

    Background Despite significant progress in imaging technologies, the efficient detection of edges and elongated features in images of intracellular and multicellular structures acquired using light or electron microscopy is a challenging and time consuming task in many laboratories. Results We present a novel method, based on the discrete curvelet transform, to extract a directional field from the image that indicates the location and direction of the edges. This directional field is then processed using the non-maximal suppression and thresholding steps of the Canny algorithm to trace along the edges and mark them. Optionally, the edges may then be extended along the directions given by the curvelets to provide a more connected edge map. We compare our scheme to the Canny edge detector and an edge detector based on Gabor filters, and show that our scheme performs better in detecting larger, elongated structures possibly composed of several step or ridge edges. Conclusion The proposed curvelet based edge detection is a novel and competitive approach for imaging problems. We expect that the methodology and the accompanying software will facilitate and improve edge detection in images available using light or electron microscopy. PMID:19257905

  4. Jet formation at the sea ice edge

    NASA Astrophysics Data System (ADS)

    Feltham, D. L.; Heorton, H. D.

    2014-12-01

    The sea ice edge presents a region of many feedback processes between the atmosphere, ocean and sea ice, which are inadequately represented in current climate models. Here we focus on on-ice atmospheric and oceanic flows at the sea ice edge. Mesoscale jet formation due to the Coriolis effect is well understood over sharp changes in surface roughness such as coastlines. This sharp change in surface roughness is experienced by the atmosphere flowing over, and ocean flowing under, a compacted sea ice edge. We have studied a dynamic sea ice edge responding to atmospheric and oceanic jet formation. The shape and strength of atmospheric and oceanic jets during on-ice flows is calculated from existing studies of the sea ice edge and prescribed to idealised models of the sea ice edge. An idealised analytical model of sea ice drift is developed and compared to a sea ice climate model (the CICE model) run on an idealised domain. The response of the CICE model to jet formation is tested at various resolutions. We find that the formation of atmospheric jets during on-ice winds at the sea ice edge increases the wind speed parallel to the sea ice edge and results in the formation of a sea ice edge jet. The modelled sea ice edge jet is in agreement with an observed jet although more observations are needed for validation. The increase in ice drift speed is dependent upon the angle between the ice edge and wind and can result in a 40% increase in ice transport along the sea ice edge. The possibility of oceanic jet formation during on-ice currents and the resultant effect upon the sea ice edge is less conclusive. Observations and climate model data of the polar oceans has been analysed to show areas of likely atmospheric jet formation, with the Fram Strait being of particular interest.

  5. Soft edges--organizational structure in dental education.

    PubMed

    Chambers, D W

    1995-03-01

    There is no one best organizational structure for dental schools or for their major subunits. The classical alternatives of functional and divisional organization are discussed in light of the rule that follows function, and the advantages and disadvantages of each are presented. Newer models--decentralization, matrix, and heterarchy--show how features of functional and divisional structure can be blended. Virtual organizations, systems theory, and networks are also considered as new expressions of classical structures. The principle of suboptimization (soft edges) is presented.

  6. Multicultural Counseling Schools: A Practical Handbook.

    ERIC Educational Resources Information Center

    Pedersen, Paul B.; Carey, John C.

    The second edition of "Multicultural Counseling in Schools" documents the tremendous change and improvement that is evident in the theory and practice of multicultural school counseling. Consistent with the new directions of the American School Counselor Association, this edition reflects cutting-edge thinking about the proper role and function of…

  7. Edge Magnon Excitation in Spin Dimer Systems

    NASA Astrophysics Data System (ADS)

    Sakaguchi, Ryo; Matsumoto, Masashige

    2016-10-01

    Magnetic excitation in a spin dimer system on a bilayer honeycomb lattice is investigated in the presence of a zigzag edge, where disordered and ordered phases can be controlled by a quantum phase transition. In analogy with the case of graphene with a zigzag edge, a flat edge magnon mode appears in the disordered phase. In an ordered phase, a finite magnetic moment generates a mean-field potential to the magnon. Since the potential is nonuniform on the edge and bulk sites, it affects the excitation, and the dispersion of the edge mode deviates from the flat shape. We investigate how the edge magnon mode evolves when the phase changes through the quantum phase transition and discuss the similarities to ordered spin systems on a monolayer honeycomb lattice.

  8. Giving curriculum planners an edge

    PubMed Central

    Oandasan, Ivy F.; Archibald, Douglas; Authier, Louise; Lawrence, Kathrine; McEwen, Laura April; Palacios, Maria; Parkkari, Marie; Plant, Heidi; Slade, Steve; Ross, Shelley

    2015-01-01

    Abstract Objective To pilot a survey of family medicine residents entering residency, describing their exposure to family medicine and their perspectives related to their future intentions to practise family medicine, in order to inform curriculum planners; and to test the methodology, feasibility, and utility of delivering a longitudinal survey to multiple residency programs. Design Pilot study using surveys. Setting Five Canadian residency programs. Participants A total of 454 first-year family medicine residents were surveyed. Main outcome measures Residents’ previous exposure to family medicine, perspectives on family medicine, and future practice intentions. Results Overall, 70% of first-year residents surveyed responded (n = 317). Although only 5 residency programs participated, respondents included graduates from each of the medical schools in Canada, as well as international medical graduates. Among respondents, 92% felt positive or strongly positive about their choice to be family physicians. Most (73%) indicated they had strong or very strong exposure to family medicine in medical school, yet more than 40% had no or minimal exposure to key clinical domains of family medicine like palliative care, home care, and care of underserved groups. Similar responses were found about residents’ lack of intention to practise in these domains. Conclusion Exposure to clinical domains in family medicine could influence future practice intentions. Surveys at entrance to residency can help medical school and family medicine residency planners consider important learning experiences to include in training. PMID:26052601

  9. Moveable Leading Edge Device for a Wing

    NASA Technical Reports Server (NTRS)

    Pitt, Dale M. (Inventor); Eckstein, Nicholas Stephen (Inventor)

    2013-01-01

    A method and apparatus for managing a flight control surface system. A leading edge section on a wing of an aircraft is extended into a deployed position. A deformable section connects the leading edge section to a trailing section. The deformable section changes from a deformed shape to an original shape when the leading edge section is moved into the deployed position. The leading edge section on the wing is moved from the deployed position to an undeployed position. The deformable section changes to the deformed shape inside of the wing.

  10. An edge index for topological insulators

    NASA Astrophysics Data System (ADS)

    Prodan, Emil

    2009-03-01

    Topological insulators display dissipationless currents flowing at the edges of the samples. These currents are associated to chiral edge modes, whose existence is intrinsically linked to the topology of the electronic states of the bulk. The edge modes can be easily investigated when the edges are smooth and have a periodicity, but as soon as the periodicity is absent, the problem becomes un-traceable by purely theoretical means. In my talk I will exemplify the use of non-commutative calculus to explore the properties, especially the stability of the edge modes. For example, using such techniques one can give a fairly elementary proof that the edge modes in Chern insulators survive even for a rough (random) edge. Similarly, for the Spin-Hall effect, one can define an observable and its associated current whose conductance remains quantized during various deformations of the Hamiltonian system. It turns out that in all cases, the edge conductance is given by the index of a Fredholm operator, which provides a new topological invariant linked directly to the edge rather than the bulk.

  11. Visible imaging of edge turbulence in NSTX

    SciTech Connect

    S. Zweben; R. Maqueda; K. Hill; D. Johnson; et al

    2000-06-13

    Edge plasma turbulence in tokamaks and stellarators is believed to cause the radical heat and particle flux across the separatrix and into the scrape-off-layers of these devices. This paper describes initial measurements of 2-D space-time structure of the edge density turbulence made using a visible imaging diagnostic in the National Spherical Torus Experiment (NSTX). The structure of the edge turbulence is most clearly visible using a method of gas puff imaging to locally illuminate the edge density turbulence.

  12. BHZ model edge states on Mobius strip

    NASA Astrophysics Data System (ADS)

    Mogni, Christopher; Vakaryuk, Victor; Tchernyshyov, Oleg

    2014-03-01

    We present analytical edge state solutions to the Bernevig-Hughes-Zhang (BHZ) model of a quantum spin hall topological insulator with Mobius geometry. The edge state solutions are obtained by solving the differential equations governing the BHZ model. The edge states satisfy both inverted periodic boundary conditions and single-valuedness boundary conditions. Furthermore, we develop a classification of boundary conditions compatible with the BHZ model insulator with Mobius geometry. We demonstrate that in the limit of large strip length that there exists a finite energy gap between the edge states. This energy gap does not exist for strips with periodic boundary conditions.

  13. Efficient edge-guided full-waveform inversion by Canny edge detection and bilateral filtering algorithms

    NASA Astrophysics Data System (ADS)

    Xiang, Shiming; Zhang, Haijiang

    2016-11-01

    It is known full-waveform inversion (FWI) is generally ill-conditioned and various strategies including pre-conditioning and regularizing the inversion system have been proposed to obtain a reliable estimation of the velocity model. Here, we propose a new edge-guided strategy for FWI in frequency domain to efficiently and reliably estimate velocity models with structures of the size similar to the seismic wavelength. The edges of the velocity model at the current iteration are first detected by the Canny edge detection algorithm that is widely used in image processing. Then, the detected edges are used for guiding the calculation of FWI gradient as well as enforcing edge-preserving total variation (TV) regularization for next iteration of FWI. Bilateral filtering is further applied to remove noise but keep edges of the FWI gradient. The proposed edge-guided FWI in the frequency domain with edge-guided TV regularization and bilateral filtering is designed to preserve model edges that are recovered from previous iterations as well as from lower frequency waveforms when FWI is conducted from lower to higher frequencies. The new FWI method is validated using the complex Marmousi model that contains several steeply dipping fault zones and hundreds of horizons. Compared to FWI without edge guidance, our proposed edge-guided FWI recovers velocity model anomalies and edges much better. Unlike previous image-guided FWI or edge-guided TV regularization strategies, our method does not require migrating seismic data, thus is more efficient for real applications.

  14. Saturn's Rings Edge-on

    NASA Technical Reports Server (NTRS)

    1995-01-01

    In one of nature's most dramatic examples of 'now-you see-them, now-you-don't', NASA's Hubble Space Telescope captured Saturn on May 22, 1995 as the planet's magnificent ring system turned edge-on. This ring-plane crossing occurs approximately every 15 years when the Earth passes through Saturn's ring plane.

    For comparison, the top picture was taken by Hubble on December 1, 1994 and shows the rings in a more familiar configuration for Earth observers.

    The bottom picture was taken shortly before the ring plane crossing. The rings do not disappear completely because the edge of the rings reflects sunlight. The dark band across the middle of Saturn is the shadow of the rings cast on the planet (the Sun is almost 3 degrees above the ring plane.) The bright stripe directly above the ring shadow is caused by sunlight reflected off the rings onto Saturn's atmosphere. Two of Saturn's icy moons are visible as tiny starlike objects in or near the ring plane. They are, from left to right, Tethys (slightly above the ring plane) and Dione.

    This observation will be used to determine the time of ring-plane crossing and the thickness of the main rings and to search for as yet undiscovered satellites. Knowledge of the exact time of ring-plane crossing will lead to an improved determination of the rate at which Saturn 'wobbles' about its axis (polar precession).

    Both pictures were taken with Hubble's Wide Field Planetary Camera 2. The top image was taken in visible light. Saturn's disk appears different in the bottom image because a narrowband filter (which only lets through light that is not absorbed by methane gas in Saturn's atmosphere) was used to reduce the bright glare of the planet. Though Saturn is approximately 900 million miles away, Hubble can see details as small as 450 miles across.

    The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science

  15. The reconstructed edges of the hexagonal BN

    NASA Astrophysics Data System (ADS)

    Zhao, Ruiqi; Gao, Junfeng; Liu, Zhongfan; Ding, Feng

    2015-05-01

    As an important two-dimensional material which shows exceptional mechanical and chemical stability, superior electronic properties, along with broad applications, the hexagonal-BN (h-BN) has drawn great attention recently. Here we report a systematic study on the structural stability, electronic and magnetic properties of various h-BN edges, including both bare and hydrogen-terminated ones. It is found that along the armchair (AC) direction, the pristine edge is the most stable one because of the formation of a triple B\\z.tbd N bond, while, along the zigzag (ZZ) directions, the reconstructed ones, ZZB + N and ZZN57 are more stable. The pristine edges are more stable in bare BN in most cases if saturated with hydrogen. By applying the theory of Wulff construction, we predicted that an unpassivated BN domain prefers the hexagonal shape enclosed with bare AC edges i.e., AC-Ns, AC, AC-Bs if the feedstock varies from N-rich to B-rich. However, the evolution from ZZN edged triangular domain, to hexagonal domain enclosed with AC edges, and ZZB edged triangle may occur if the edges are terminated by hydrogen atoms. Further calculation shows that these edges present rich type-dependent properties and thus are important for various applications. This theoretical study showed that controlling the morphologies of BN domains and BN edges is crucial for various applications.As an important two-dimensional material which shows exceptional mechanical and chemical stability, superior electronic properties, along with broad applications, the hexagonal-BN (h-BN) has drawn great attention recently. Here we report a systematic study on the structural stability, electronic and magnetic properties of various h-BN edges, including both bare and hydrogen-terminated ones. It is found that along the armchair (AC) direction, the pristine edge is the most stable one because of the formation of a triple B\\z.tbd N bond, while, along the zigzag (ZZ) directions, the reconstructed ones, ZZB + N

  16. WWC Quick Review of the Article "Technology's Edge: The Educational Benefits of Computer-Aided Instruction"

    ERIC Educational Resources Information Center

    What Works Clearinghouse, 2010

    2010-01-01

    The study, "Technology's Edge: The Educational Benefits of Computer-Aided Instruction," examined whether the "I CAN Learn"[R] computer-based curriculum is more effective than traditional classroom instruction at teaching pre-algebra and algebra concepts to middle- and high-school students. The study included about 1,600 students in 15 high schools…

  17. Libby School Leaders: Principals--Past to Present.

    ERIC Educational Resources Information Center

    Downing, Cassie, Ed.; McGarity, Fiona, Ed.

    2000-01-01

    This issue of "Loblolly Magazine," written and edited by Texas high school students, features two female principals in the Carthage, Texas, school system. Dura Heaton Lampin was the first principal of Libby Elementary School (built in 1955) and the first woman principal in the Carthage school system. Rosa Lee Edge was the second principal of Libby…

  18. Where Big-City Schools Meet "Microsoft Smarts"

    ERIC Educational Resources Information Center

    Borja, Rhea R.

    2006-01-01

    This article talks about a new school built, which is called "School of the Future," which was born of a partnership between the Philadelphia public schools and the world's leading software-maker, Microsoft Corp. A gleaming white building on the edge of a blighted West Philadelphia neighborhood, the $62 million school garnered wide attention when…

  19. Absence of edge states in covalently bonded zigzag edges of graphene on Ir(111).

    PubMed

    Li, Yan; Subramaniam, Dinesh; Atodiresei, Nicolae; Lazić, Predrag; Caciuc, Vasile; Pauly, Christian; Georgi, Alexander; Busse, Carsten; Liebmann, Marcus; Blügel, Stefan; Pratzer, Marco; Morgenstern, Markus; Mazzarello, Riccardo

    2013-04-11

    The zigzag edges of graphene on Ir(111) are studied by ab initio simulations and low-temperature scanning tunneling spectroscopy, providing information about their structural, electronic, and magnetic properties. No edge state is found to exist, which is explained in terms of the interplay between a strong geometrical relaxation at the edge and a hybridization of the d orbitals of Ir atoms with the graphene orbitals at the edge.

  20. Full Service Community Schools: Prevention of Delinquency in Students with Mental Illness and/or Poverty

    ERIC Educational Resources Information Center

    Kronick, Robert F.

    2005-01-01

    This book is about children who are living dangerously close to the edge, the edge of delinquency, mental illness, and poverty. Beginning with a discussion of the role of Joy Dryfoos in the development of comprehensive schools, this work is based on the Full Service Schools program which began in 1998 in three elementary inner-city schools in…

  1. Eliminating Unbonded Edges In Explosive Bonding

    NASA Technical Reports Server (NTRS)

    Bement, Laurence J.; Kushnick, Anne C.

    1991-01-01

    Explosive-bonding technique elminates sharp unbonded notch normally occurring between flyer plate and baseplate. Makes it possible to simply break away unbonded outer extremity of flyer plate; no longer necessary to grind away unbonded edge to prevent collection of corrosive contaminants in edge voids. Method not limited to flat surfaces.

  2. How Forest Inhomogeneities Affect the Edge Flow

    NASA Astrophysics Data System (ADS)

    Boudreault, Louis-Étienne; Dupont, Sylvain; Bechmann, Andreas; Dellwik, Ebba

    2016-09-01

    Most of our knowledge on forest-edge flows comes from numerical and wind-tunnel experiments where canopies are horizontally homogeneous. To investigate the impact of tree-scale heterogeneities ({>}1 m) on the edge-flow dynamics, the flow in an inhomogeneous forest edge on Falster island in Denmark is investigated using large-eddy simulation. The three-dimensional forest structure is prescribed in the model using high resolution helicopter-based lidar scans. After evaluating the simulation against wind measurements upwind and downwind of the forest leading edge, the flow dynamics are compared between the scanned forest and an equivalent homogeneous forest. The simulations reveal that forest inhomogeneities facilitate flow penetration into the canopy from the edge, inducing important dispersive fluxes in the edge region as a consequence of the flow spatial variability. Further downstream from the edge, the forest inhomogeneities accentuate the canopy-top turbulence and the skewness of the wind-velocity components while the momentum flux remains unchanged. This leads to a lower efficiency in the turbulent transport of momentum within the canopy. Dispersive fluxes are only significant in the upper canopy. Above the canopy, the mean flow is less affected by the forest inhomogeneities. The inhomogeneities induce an increase in the mean wind speed that was found to be equivalent to a decrease in the aerodynamic height of the canopy. Overall, these results highlight the importance of forest inhomogeneities when looking at canopy-atmosphere exchanges in forest-edge regions.

  3. Cutting a Tapered Edge on Padding Material

    NASA Technical Reports Server (NTRS)

    Mitchell, M. J.

    1982-01-01

    Resilience and flexibility of felt, rubber, or other padding materials allow them to be clamped in form block, cut straight down, and then released to produce straight clean tapered edge. With material held in slanted position, edge can be cut straight down; hence cut depth is minimum.

  4. More results on oscillating edge-flames

    NASA Astrophysics Data System (ADS)

    Buckmaster, J.; Hegab, A.; Jackson, T. L.

    2000-06-01

    We examine a simple model of a side-anchored non-premixed edge-flame in order to gain insights into the oscillations that are sometimes observed in microgravity candle burning, flame-spread over liquids, etc. Previous results describe the role played by the Lewis number of the fuel, and the Damköhler number, and here we examine both the effects of an on-edge and off-edge convective flow, and the effects of a heat sink. The on-edge flow and the heat sink tend to destabilize and the off-edge flow tends to stabilize, results consistent with our hypothesis regarding the genesis of the oscillations.

  5. Magnetism of zigzag edge phosphorene nanoribbons

    SciTech Connect

    Zhu, Zhili E-mail: jiayu@zzu.edu.cn; Li, Chong; Yu, Weiyang; Chang, Dahu; Sun, Qiang; Jia, Yu E-mail: jiayu@zzu.edu.cn

    2014-09-15

    We have investigated, by means of ab initio calculations, the electronic and magnetic structures of zigzag edge phosphorene nanoribbons (ZPNRs) with various widths. The stable magnetic state was found in pristine ZPNRs by allowing the systems to be spin-polarized. The ground state of pristine ZPNRs prefers ferromagnetic order in the same edge but antiferromagnetic order between two opposite edges. The magnetism arises from the dangling bond states as well as edge localized π-orbital states. The presence of a dangling bond is crucial to the formation of the magnetism of ZPNRs. The hydrogenated ZPNRs get nonmagnetic semiconductors with a direct band gap. While, the O-saturated ZPNRs show magnetic ground states due to the weak P-O bond in the ribbon plane between the p{sub z}-orbitals of the edge O and P atoms.

  6. Elastically Deformable Side-Edge Link for Trailing-Edge Flap Aeroacoustic Noise Reduction

    NASA Technical Reports Server (NTRS)

    Khorrami, Mehdi R. (Inventor); Lockard, David P. (Inventor); Moore, James B. (Inventor); Su, Ji (Inventor); Turner, Travis L. (Inventor); Lin, John C. (Inventor); Taminger, Karen M. (Inventor); Kahng, Seun K. (Inventor); Verden, Scott A. (Inventor)

    2014-01-01

    A system is provided for reducing aeroacoustic noise generated by an aircraft having wings equipped with trailing-edge flaps. The system includes a plurality of elastically deformable structures. Each structure is coupled to and along one of the side edges of one of the trailing-edge flaps, and is coupled to a portion of one of the wings that is adjacent to the one of the side edges. The structures elastically deform when the trailing-edge flaps are deployed away from the wings.

  7. TCT measurements with slim edge strip detectors

    NASA Astrophysics Data System (ADS)

    Mandić, Igor; Cindro, Vladimir; Gorišek, Andrej; Kramberger, Gregor; Mikuž, Marko; Zavrtanik, Marko; Fadeyev, Vitaliy; Sadrozinski, Hartmut F.-W.; Christophersen, Marc; Phlips, Bernard

    2014-07-01

    Transient current technique (TCT) measurements with focused laser light on miniature silicon strip detectors (n+-type strips on p-type bulk) with one inactive edge thinned to about 100 μm using the Scribe-Cleave-Passivate (SCP) method are presented. Pulses of focused IR (λ=1064 nm) laser light were directed to the surface of the detector and charge collection properties near the slim edge were investigated. Measurements before and after irradiation with reactor neutrons up to 1 MeV equivalent fluence of 1.5×1015 neq/cm2 showed that SCP thinning of detector edge does not influence its charge collection properties. TCT measurements were done also with focused red laser beam (λ=640 nm) directed to the SCP processed side of the detector. The absorption length of red light in silicon is about 3 μm so with this measurement information about the electric field at the edge can be obtained. Observations of laser induced signals indicate that the electric field distribution along the depth of the detector at the detector edge is different than in the detector bulk: electric field is higher near the strip side and lower at the back side. This is a consequence of negative surface charge caused by passivation of the cleaved edge with Al2O3. The difference between bulk and edge electric field distributions gets smaller after irradiation.

  8. Technidilaton at the conformal edge

    SciTech Connect

    Hashimoto, Michio; Yamawaki, Koichi

    2011-01-01

    Technidilaton (TD) was proposed long ago in the technicolor near criticality/conformality. To reveal the critical behavior of TD, we explicitly compute the nonperturbative contributions to the scale anomaly <{theta}{sub {mu}}{sup {mu}>} and to the technigluon condensate <{alpha}G{sub {mu}{nu}}{sup 2}>, which are generated by the dynamical mass m of the technifermions. Our computation is based on the (improved) ladder Schwinger-Dyson equation, with the gauge coupling {alpha} replaced by the two-loop running coupling {alpha}({mu}) having the Caswell-Banks-Zaks infrared fixed point {alpha}{sub *}: {alpha}({mu}){approx_equal}{alpha}={alpha}{sub *} for the infrared region m<{mu}<{Lambda}{sub TC}, where {Lambda}{sub TC} is the intrinsic scale (analogue of {Lambda}{sub QCD} of QCD) relevant to the perturbative scale anomaly. We find that -<{theta}{sub {mu}}{sup {mu}}>/m{sup 4}{yields}const{ne}0 and <{alpha}G{sub {mu}}{nu}{sup 2}>/m{sup 4}{yields}({alpha}/{alpha}{sub cr}-1){sup -3/2}{yields}{infinity} in the criticality limit m/{Lambda}{sub TC}{approx}exp(-{pi}/({alpha}/{alpha}{sub cr}-1){sup 1/2}){yields}0 ({alpha}={alpha}{sub *}=>{alpha}{sub cr}, or N{sub f} approaches N{sub f}{sup cr}) ('conformal edge'). Our result precisely reproduces the formal identity <{theta}{sub {mu}}{sup {mu}>}=({beta}({alpha})/4{alpha}{sup 2})<{alpha}G{sub {mu}{nu}}{sup 2}>, where {beta}({alpha})={Lambda}{sub TC}({partial_derivative}{alpha}/{partial_derivative}{Lambda}{sub TC})=-(2{alpha}{sub cr}/{pi}){center_dot}({alpha}/{alpha}{sub cr}-1){sup 3/2} is the nonperturbative beta function corresponding to the above essential singularity scaling of m/{Lambda}{sub TC}. Accordingly, the partially conserved dilatation current implies (M{sub TD}/m){sup 2}(F{sub TD}/m){sup 2}=-4<{theta}{sub {mu}}{sup {mu}}>/m{sup 4}{yields}const{ne}0 at criticality limit, where M{sub TD} is the mass of TD and F{sub TD} the decay constant of TD. We thus conclude that at criticality limit the TD could become a ''true

  9. Formation of Klein Edge Doublets from Graphene Monolayers.

    PubMed

    Kim, Judy S; Warner, Jamie H; Robertson, Alex W; Kirkland, Angus I

    2015-09-22

    With increasing possibilities for applications of graphene, it is essential to fully characterize the rich topological variations in graphene edge structures. Using aberration-corrected transmission electron microscopy, dangling carbon doublets at the edge of monolayer graphene crystals have been observed. Unlike the single-atom Klein edge often found at zigzag edges, these carbon dimers were observed in various edge structure environments, but most frequently on the more stable armchair edges. Observation of this Klein edge doublet over time reveals that its existence enhances the stability of armchair edges and is a route to atom abstraction on zigzag edges.

  10. An edge preserving differential image coding scheme

    NASA Technical Reports Server (NTRS)

    Rost, Martin C.; Sayood, Khalid

    1992-01-01

    Differential encoding techniques are fast and easy to implement. However, a major problem with the use of differential encoding for images is the rapid edge degradation encountered when using such systems. This makes differential encoding techniques of limited utility, especially when coding medical or scientific images, where edge preservation is of utmost importance. A simple, easy to implement differential image coding system with excellent edge preservation properties is presented. The coding system can be used over variable rate channels, which makes it especially attractive for use in the packet network environment.

  11. Image Edge Extraction via Fuzzy Reasoning

    NASA Technical Reports Server (NTRS)

    Dominquez, Jesus A. (Inventor); Klinko, Steve (Inventor)

    2008-01-01

    A computer-based technique for detecting edges in gray level digital images employs fuzzy reasoning to analyze whether each pixel in an image is likely on an edge. The image is analyzed on a pixel-by-pixel basis by analyzing gradient levels of pixels in a square window surrounding the pixel being analyzed. An edge path passing through the pixel having the greatest intensity gradient is used as input to a fuzzy membership function, which employs fuzzy singletons and inference rules to assigns a new gray level value to the pixel that is related to the pixel's edginess degree.

  12. Electrostatic analysis of the tokamak edge plasma

    SciTech Connect

    Motley, R.W.

    1981-07-01

    The intrusion of an equipotential poloidal limiter into the edge plasma of a circular tokamak discharge distorts the axisymmetry in two ways: (1) it (partially) shorts out the top-to-bottom Pfirsch-Schlueter driving potentials, and (2) it creates zones of back current flow into the limiter. The resulting boundary mismatch between the outer layers and the inner axisymmetric Pfirsch-Schlueter layer provides free energy to drive the edge plasma unstable. Special limiters are proposed to symmetrize the edge plasma and thereby reduce the electrical and MHD activity in the boundary layer.

  13. Differential Search Algorithm Based Edge Detection

    NASA Astrophysics Data System (ADS)

    Gunen, M. A.; Civicioglu, P.; Beşdok, E.

    2016-06-01

    In this paper, a new method has been presented for the extraction of edge information by using Differential Search Optimization Algorithm. The proposed method is based on using a new heuristic image thresholding method for edge detection. The success of the proposed method has been examined on fusion of two remote sensed images. The applicability of the proposed method on edge detection and image fusion problems have been analysed in detail and the empirical results exposed that the proposed method is useful for solving the mentioned problems.

  14. Cavitation on hydrofoils with sinusoidal leading edge

    NASA Astrophysics Data System (ADS)

    Johari, H.

    2015-12-01

    Cavitation characteristics of hydrofoils with sinusoidal leading edge were examined experimentally at a Reynolds number of 7.2 × 105. The hydrofoils had an underlying NACA 634-021 profile and an aspect ratio of 4.3. The sinusoidal leading edge geometries included three amplitudes of 2.5%, 5%, and 12% and two wavelengths of 25% and 50% of the mean chord length. Results revealed that cavitation on the leading edge-modified hydrofoils existed in pockets behind the troughs whereas the baseline hydrofoil produced cavitation along its entire span. Moreover, cavitation on the modified hydrofoils appeared at consistently lower angles of attack than on the baseline hydrofoil.

  15. Stresses in edge stiffened anisotropic sandwich plate

    NASA Astrophysics Data System (ADS)

    Rao, Koganti M.; Rao, Y. U. M.

    Hybrid-stress finite elements are used to study the static behavior of an edge stiffened anisotropic sandwich plate subjected to cylindrical bending. The stress concentration factors at the interface of core and stiffener are evaluated. The analysis of the simply-supported sandwich indicates that the state of stress at the interface of core and stiffener is increased and that the edge stiffener induces clamping conditions. The faces and stiffener at the edge are, respectively, subjected to negative and positive transverse shear, causing considerable bending action in faces about their own centroidal axis.

  16. An edge preserving differential image coding scheme

    NASA Technical Reports Server (NTRS)

    Rost, Martin C.; Sayood, Khalid

    1991-01-01

    Differential encoding techniques are fast and easy to implement. However, a major problem with the use of differential encoding for images is the rapid edge degradation encountered when using such systems. This makes differential encoding techniques of limited utility especially when coding medical or scientific images, where edge preservation is of utmost importance. We present a simple, easy to implement differential image coding system with excellent edge preservation properties. The coding system can be used over variable rate channels which makes it especially attractive for use in the packet network environment.

  17. Edge of chaos and genesis of turbulence.

    PubMed

    Chian, Abraham C-L; Muñoz, Pablo R; Rempel, Erico L

    2013-11-01

    The edge of chaos is analyzed in a spatially extended system, modeled by the regularized long-wave equation, prior to the transition to permanent spatiotemporal chaos. In the presence of coexisting attractors, a chaotic saddle is born at the basin boundary due to a smooth-fractal metamorphosis. As a control parameter is varied, the chaotic transient evolves to well-developed transient turbulence via a cascade of fractal-fractal metamorphoses. The edge state responsible for the edge of chaos and the genesis of turbulence is an unstable traveling wave in the laboratory frame, corresponding to a saddle point lying at the basin boundary in the Fourier space. PMID:24329334

  18. Composite laminate free edge reinforcement concepts

    NASA Technical Reports Server (NTRS)

    Howard, W. E.; Gossard, T., Jr.; Jones, R. M.

    1985-01-01

    The presence of a free edge in a laminated composite structure can result in delamination of the composite under certain loading conditions. Linear finite element analysis predicts large or even singular interlaminar stresses near the free edge. Edge reinforcements which will reduce these interlaminar stresses, prevent or delay the onset of delaminations, and thereby increase the strength and life of the structure were studied. Finite element models are used to analyze reinforced laminates which were subsequently fabricated and loaded to failure in order to verify the analysis results.

  19. Edge states in a honeycomb lattice: effects of anisotropic hopping and mixed edges

    SciTech Connect

    Dahal, Hari P; Balatsky, Alexander V; Sinistsyn, N A; Hu, Zi - Xiang; Yang, Kun

    2008-01-01

    We study the edge states in graphene in the presence of a magnetic field perpendicular to the plane of the lattice. Most of the work done so far discusses the edge states in either zigzag or armchair edge graphene considering an isotropic electron hopping. In practice, graphene can have a mixture of armchair and zigzag edges and the electron hopping can be anisotropic, which is the subject of this article. We predict that the mixed edges smear the enhanced local density of states (LDOS) at E=0 of the zigzag edge and, on the other hand, the anisotropic hopping gives rise to the enhanced LDOS at E=0 in the armchair edge. The behavior of the LDOS can be studied using scanning tunneling microscopy (STM) experiments. We suggest that care must be taken while interpreting the STM data, because the clear distinction between the zigzag edge (enhanced LDOS at E=0) and armchair edge (suppressed LDOS at E=0) can be lost if the hopping is not isotropic and if the edges are mixed.

  20. Survey of atomic processes in edge plasmas

    SciTech Connect

    Janev, R.K.; Post, D.E.; Langer, W.D.; Evans, K.; Heifetz, D.B.; Weisheit, J.C.

    1983-11-01

    A review of the most important reactions of atomic and molecular hydrogen with the fusion edge plasma electrons and ions is presented. An appropriate characterization of the considered collision processes, useful in plasma edge studies (evaluated cross sections, reaction rates, energy gain/loss per collision, etc.) has been performed. While a complete survey of atomic physics of fusion edge plasmas will be given elsewhere shortly, we demonstrate here the relevance of the atomic collision processes for describing the physical state of edge plasmas and understanding the energy balance in cool divertor plasmas. It is found that the excited neutral species play an important role in the low-temperature, high-density plasmas.

  1. Miniature Trailing Edge Effector for Aerodynamic Control

    NASA Technical Reports Server (NTRS)

    Lee, Hak-Tae (Inventor); Bieniawski, Stefan R. (Inventor); Kroo, Ilan M. (Inventor)

    2008-01-01

    Improved miniature trailing edge effectors for aerodynamic control are provided. Three types of devices having aerodynamic housings integrated to the trailing edge of an aerodynamic shape are presented, which vary in details of how the control surface can move. A bucket type device has a control surface which is the back part of a C-shaped member having two arms connected by the back section. The C-shaped section is attached to a housing at the ends of the arms, and is rotatable about an axis parallel to the wing trailing edge to provide up, down and neutral states. A flip-up type device has a control surface which rotates about an axis parallel to the wing trailing edge to provide up, down, neutral and brake states. A rotating type device has a control surface which rotates about an axis parallel to the chord line to provide up, down and neutral states.

  2. Folded membrane dialyzer with mechanically sealed edges

    DOEpatents

    Markley, Finley W.

    1976-01-01

    A semipermeable membrane is folded in accordion fashion to form a stack of pleats and the edges are sealed so as to isolate the opposite surfaces of the membrane. The stack is contained within a case that provides ports for flow of blood in contact with one surface of the membrane through channels formed by the pleats and also provides ports for flow of a dialysate through channels formed by the pleats in contact with the other surface of the membrane. The serpentine side edges of the membrane are sealed by a solidified plastic material, whereas effective mechanical means are provided to seal the end edges of the folded membrane. The mechanical means include a clamping strip which biases case sealing flanges into a sealed relationship with end portions of the membrane near the end edges, which portions extend from the stack and between the sealing flanges.

  3. Overview of Edge Simulation Laboratory (ESL)

    NASA Astrophysics Data System (ADS)

    Cohen, R. H.; Dorr, M.; Hittinger, J.; Rognlien, T.; Umansky, M.; Xiong, A.; Xu, X.; Belli, E.; Candy, J.; Snyder, P.; Colella, P.; Martin, D.; Sternberg, T.; van Straalen, B.; Bodi, K.; Krasheninnikov, S.

    2006-10-01

    The ESL is a new collaboration to build a full-f electromagnetic gyrokinetic code for tokamak edge plasmas using continuum methods. Target applications are edge turbulence and transport (neoclassical and anomalous), and edge-localized modes. Initially the project has three major threads: (i) verification and validation of TEMPEST, the project's initial (electrostatic) edge code which can be run in 4D (neoclassical and transport-timescale applications) or 5D (turbulence); (ii) design of the next generation code, which will include more complete physics (electromagnetics, fluid equation option, improved collisions) and advanced numerics (fully conservative, high-order discretization, mapped multiblock grids, adaptivity), and (iii) rapid-prototype codes to explore the issues attached to solving fully nonlinear gyrokinetics with steep radial gradiens. We present a brief summary of the status of each of these activities.

  4. Edge energies and shapes of nanoprecipitates.

    SciTech Connect

    Hamilton, John C.

    2006-01-01

    In this report we present a model to explain the size-dependent shapes of lead nano-precipitates in aluminum. Size-dependent shape transitions, frequently observed at nanolength scales, are commonly attributed to edge energy effects. This report resolves an ambiguity in the definition and calculation of edge energies and presents an atomistic calculation of edge energies for free clusters. We also present a theory for size-dependent shapes of Pb nanoprecipitates in Al, introducing the concept of ''magic-shapes'' defined as precipitate shapes having near zero elastic strains when inserted into similarly shaped voids in the Al matrix. An algorithm for constructing a complete set of magic-shapes is presented. The experimental observations are explained by elastic strain energies and interfacial energies; edge energies play a negligible role. We replicate the experimental observations by selecting precipitates having magic-shapes and interfacial energies less than a cutoff value.

  5. Leading edge protection for composite blades

    NASA Technical Reports Server (NTRS)

    Brantley, J. W.; Irwin, T. P. (Inventor)

    1977-01-01

    A laminated filament composite structure, such as an airfoil for use in an environment in which it is subjected to both foreign object impact and bending is provided with improved leading edge protection. At least one fine wire mesh layer is partially bonded within the composite structure along its neutral bending axis. A portion of the wire mesh layer extends beyond the neutral bending axis and partially around the leading edge where it is bonded to the outer periphery of the primary composite structure. The wire mesh is clad with a metal such as nickel to provide an improved leading edge protective device which is firmly anchored within the composite structure. Also described is a novel method of constructing a composite airfoil so as to further minimize the possibility of losing the leading edge protective device due to delamination caused by impact and bending.

  6. Mechanotunable monatomic metal structures at graphene edges.

    PubMed

    Wei, Ning; Chang, Cheng; Zhu, Hongwei; Xu, Zhiping

    2014-06-14

    Monatomic metal (e.g. silver) structures could form preferably at graphene edges. We explore their structural and electronic properties by performing density functional theory based first-principles calculations. The results show that cohesion between metal atoms, as well as electronic coupling between metal atoms and graphene edges offer remarkable structural stability of the hybrid. We find that the outstanding mechanical properties of graphene allow tunable properties of the metal monatomic structures by straining the structure. The concept is extended to metal rings and helices that form at open ends of carbon nanotubes and edges of twisted graphene ribbons. These findings demonstrate the role of graphene edges as an efficient one-dimensional template for low-dimensional metal structures that are mechanotunable.

  7. Imaging The Leading Edge Of A Weld

    NASA Technical Reports Server (NTRS)

    Mcgee, William F.; Rybicki, Daniel J.

    1994-01-01

    Proposed optical system integrated into plasma arc welding torch provides image of leading edge of weld pool and welding-arc-initiation point. Welding torch aligned better with joint. System includes coherent bundle of optical fibers and transparent cup.

  8. IBFAN: on the cutting edge.

    PubMed

    Allain, A

    1989-01-01

    The story of IBFAN, the International Baby Food Action Network, from its beginning with 6 members in 1979, to its status of 140 groups worldwide in 1989 is told by its founder, Annelies Allain. IBFAN celebrated its 10th anniversary in October 1989 with a week-long Forum of 350 organizers from 67 countries. IBFAN is a single-tissue grass-roots organization, almost entirely women: the issue is that bottle-feeding kills babies. It has mounted a successful campaign ending in passage of the WHO/UNICEF International Code of Marketing of Breast-milk Substitutes in 1981. With this success, the political power of the "third system," of people, as opposed to government and transnational corporations, was recognized. The most important fundamental activity of IBFAN is to amass information to make its point that million of babies, primarily in developing countries, have died from consuming powdered formula instead of breast milk. IBFAN also set out to show that milk companies have influenced medical school training, health care providers, UN and WHO policies, and governments of developing countries through advertising and tax income. IBFAN's methods are boycott, corporate marketing analysis, shareholder, resolutions, and numerous strategies invented by local activists. The baby food industry responded by forming the International Council of Infant Food Industries, headed by a former WHO Assistant Director General, and applied for registration as an official NGO with the WHO. Again in 1987 they formed the Infant Food Manufacturers Associations, headed by a former WHO staff member, and gained WHO NGO status, claiming to advance infant nutrition and adhere to the WHO Code. Ibfan's current emphasis is on combatting free infant formula given out at maternity hospitals, the most effective way to block successful lactation, is developed as well as developing countries. An effort to monitor this activity will mark the 10th anniversary of the Code in 1991. PMID:12343253

  9. Edge Equilibrium Code (EEC) For Tokamaks

    SciTech Connect

    Li, Xujling

    2014-02-24

    The edge equilibrium code (EEC) described in this paper is developed for simulations of the near edge plasma using the finite element method. It solves the Grad-Shafranov equation in toroidal coordinate and uses adaptive grids aligned with magnetic field lines. Hermite finite elements are chosen for the numerical scheme. A fast Newton scheme which is the same as implemented in the equilibrium and stability code (ESC) is applied here to adjust the grids

  10. Galilean invariance at quantum Hall edge

    NASA Astrophysics Data System (ADS)

    Moroz, Sergej; Hoyos, Carlos; Radzihovsky, Leo

    2015-05-01

    We construct the theory of a chiral Luttinger liquid that lives on the boundary of a Galilean invariant quantum Hall fluid. In contrast to previous studies, Galilean invariance of the total (bulk plus edge) theory is guaranteed. We consider electromagnetic response at the edge and calculate momentum- and frequency-dependent electric conductivity and argue that its experimental measurement can provide a new means to determine the "shift" and bulk Hall viscosity.

  11. Edge states in polariton honeycomb lattices

    NASA Astrophysics Data System (ADS)

    Milićević, M.; Ozawa, T.; Andreakou, P.; Carusotto, I.; Jacqmin, T.; Galopin, E.; Lemaître, A.; Le Gratiet, L.; Sagnes, I.; Bloch, J.; Amo, A.

    2015-09-01

    The experimental study of edge states in atomically thin layered materials remains a challenge due to the difficult control of the geometry of the sample terminations, the stability of dangling bonds, and the need to measure local properties. In the case of graphene, localized edge modes have been predicted in zigzag and bearded edges, characterized by flat dispersions connecting the Dirac points. Polaritons in semiconductor microcavities have recently emerged as an extraordinary photonic platform to emulate 1D and 2D Hamiltonians, allowing the direct visualization of the wavefunctions in both real- and momentum-space as well as of the energy dispersion of eigenstates via photoluminescence experiments. Here we report on the observation of edge states in a honeycomb lattice of coupled micropillars. The lowest two bands of this structure arise from the coupling of the lowest energy modes of the micropillars, and emulate the π and π* bands of graphene. We show the momentum-space dispersion of the edge states associated with the zigzag and bearded edges, holding unidimensional quasi-flat bands. Additionally, we evaluate polarization effects characteristic of polaritons on the properties of these states.

  12. Aircraft wing trailing-edge noise

    NASA Technical Reports Server (NTRS)

    Underwood, R. L.; Hodgson, T. H.

    1981-01-01

    The mechanism and sound pressure level of the trailing-edge noise for two-dimensional turbulent boundary layer flow was examined. Experiment is compared with current theory. A NACA 0012 airfoil of 0.61 m chord and 0.46 m span was immersed in the laminar flow of a low turbulence open jet. A 2.54 cm width roughness strip was placed at 15 percent chord from the leading edge on both sides of the airfoil as a boundary layer trip so that two separate but statistically equivalent turbulent boundary layers were formed. Tests were performed with several trailing-edge geometries with the upstream velocity U sub infinity ranging from a value of 30.9 m/s up to 73.4 m/s. Properties of the boundary layer for the airfoil and pressure fluctuations in the vicinity of the trailing-edge were examined. A scattered pressure field due to the presence of the trailing-edge was observed and is suggested as a possible sound producing mechanism for the trailing-edge noise.

  13. On the generation of side-edge flap noise. [part span trailing edge flaps

    NASA Technical Reports Server (NTRS)

    Howe, M. S.

    1981-01-01

    A theory is proposed for estimating the noise generated at the side edges of part span trailing edge flaps in terms of pressure fluctuations measured just in-board of the side edge of the upper surface of the flap. Asymptotic formulae are developed in the opposite extremes of Lorentz contracted acoustic wavelength large/small compared with the chord of the flap. Interpolation between these limiting results enables the field shape and its dependence on subsonic forward flight speed to be predicted over the whole frequency range. It is shown that the mean width of the side edge gap between the flap and the undeflected portion of the airfoil has a significant influence on the intensity of the radiated sound. It is estimated that the noise generated at a single side edge of a full scale part span flap can exceed that produced along the whole of the trailing edge of the flap by 3 dB or more.

  14. Edge-to-Edge Oriented Self-Assembly of ReS2 Nanoflakes.

    PubMed

    Zhang, Qin; Wang, Wenjie; Kong, Xin; Mendes, Rafael G; Fang, Liwen; Xue, Yinghui; Xiao, Yao; Rümmeli, Mark H; Chen, Shengli; Fu, Lei

    2016-09-01

    The self-assembly of two-dimensional (2D) nanomaterials, an emerging research area, still remains largely unexplored. The strong interlayer attraction between 2D nanosheets leads to face-to-face stacking rather than edge-to-edge coupling. We demonstrate, for the first time, how one can induce and control an edge-to-edge self-assembly process for 2D nanomaterials. The extremely weak van der Waals coupling and strong anisotropy of ReS2 allow us to realize an oriented self-assembly (OSA) process. The aspect ratio of the resulting ReS2 nanoscrolls can be well controlled. In addition, we perform simulations to further explain and confirm the OSA process, demonstrating its great potential to be expanded as a general edge-to-edge self-assembly process suitable for other 2D nanomaterials.

  15. Edge-to-Edge Oriented Self-Assembly of ReS2 Nanoflakes.

    PubMed

    Zhang, Qin; Wang, Wenjie; Kong, Xin; Mendes, Rafael G; Fang, Liwen; Xue, Yinghui; Xiao, Yao; Rümmeli, Mark H; Chen, Shengli; Fu, Lei

    2016-09-01

    The self-assembly of two-dimensional (2D) nanomaterials, an emerging research area, still remains largely unexplored. The strong interlayer attraction between 2D nanosheets leads to face-to-face stacking rather than edge-to-edge coupling. We demonstrate, for the first time, how one can induce and control an edge-to-edge self-assembly process for 2D nanomaterials. The extremely weak van der Waals coupling and strong anisotropy of ReS2 allow us to realize an oriented self-assembly (OSA) process. The aspect ratio of the resulting ReS2 nanoscrolls can be well controlled. In addition, we perform simulations to further explain and confirm the OSA process, demonstrating its great potential to be expanded as a general edge-to-edge self-assembly process suitable for other 2D nanomaterials. PMID:27547983

  16. Nonlinear fitting of absorption edges in K-edge densitometry spectra

    SciTech Connect

    Collins, M.; Hsue, Sin-Tao

    1997-11-01

    A new method for analyzing absorption edges in K-Edge Densitometry (KED) spectra is introduced. This technique features a nonlinear function that specifies the empirical form of a broadened K-absorption edge. Nonlinear fitting of the absorption edge can be used to remove broadening effects from the KED spectrum. This allows more data near the edge to be included in the conventional KED fitting procedure. One possible benefit is enhanced precision of measured uranium and plutonium concentrations. Because no additional hardware is required, several facilities that use KED may eventually benefit from this approach. Applications of nonlinear KED fitting in the development of the Los Alamos National Laboratory (LANL) hybrid K-edge/x-ray fluorescence (XRF) densitometer system are described.

  17. The dependence of edge displacement thresholds on edge blur, contrast, and displacement distance.

    PubMed

    Mather, G

    1987-01-01

    Two experiments measured thresholds for discriminating the movement direction of an isolated intensity edge. The luminance profile of the edge took the form of an integrated Gaussian. In the first experiment, displacement thresholds were measured as a function of edge blur width and contrast. In the second experiment, contrast thresholds were measured as a function of edge blur width and displacement. Using the estimated retinal profile of the edge (given the LSF of the display and of the optics of the eye), the data were found to collapse onto a single function relating the maximum spatial luminance gradient defined by the edge to the maximum temporal change in luminance generated by its displacement. There was a direct relationship between the two gradients at threshold, so that lower spatial gradients were paired with smaller temporal changes. Implications for current models of motion detection are examined.

  18. Losing your edge: climate change and the conservation value of range-edge populations.

    PubMed

    Rehm, Evan M; Olivas, Paulo; Stroud, James; Feeley, Kenneth J

    2015-10-01

    Populations occurring at species' range edges can be locally adapted to unique environmental conditions. From a species' perspective, range-edge environments generally have higher severity and frequency of extreme climatic events relative to the range core. Under future climates, extreme climatic events are predicted to become increasingly important in defining species' distributions. Therefore, range-edge genotypes that are better adapted to extreme climates relative to core populations may be essential to species' persistence during periods of rapid climate change. We use relatively simple conceptual models to highlight the importance of locally adapted range-edge populations (leading and trailing edges) for determining the ability of species to persist under future climates. Using trees as an example, we show how locally adapted populations at species' range edges may expand under future climate change and become more common relative to range-core populations. We also highlight how large-scale habitat destruction occurring in some geographic areas where many species range edge converge, such as biome boundaries and ecotones (e.g., the arc of deforestation along the rainforest-cerrado ecotone in the southern Amazonia), can have major implications for global biodiversity. As climate changes, range-edge populations will play key roles in helping species to maintain or expand their geographic distributions. The loss of these locally adapted range-edge populations through anthropogenic disturbance is therefore hypothesized to reduce the ability of species to persist in the face of rapid future climate change.

  19. Losing your edge: climate change and the conservation value of range-edge populations.

    PubMed

    Rehm, Evan M; Olivas, Paulo; Stroud, James; Feeley, Kenneth J

    2015-10-01

    Populations occurring at species' range edges can be locally adapted to unique environmental conditions. From a species' perspective, range-edge environments generally have higher severity and frequency of extreme climatic events relative to the range core. Under future climates, extreme climatic events are predicted to become increasingly important in defining species' distributions. Therefore, range-edge genotypes that are better adapted to extreme climates relative to core populations may be essential to species' persistence during periods of rapid climate change. We use relatively simple conceptual models to highlight the importance of locally adapted range-edge populations (leading and trailing edges) for determining the ability of species to persist under future climates. Using trees as an example, we show how locally adapted populations at species' range edges may expand under future climate change and become more common relative to range-core populations. We also highlight how large-scale habitat destruction occurring in some geographic areas where many species range edge converge, such as biome boundaries and ecotones (e.g., the arc of deforestation along the rainforest-cerrado ecotone in the southern Amazonia), can have major implications for global biodiversity. As climate changes, range-edge populations will play key roles in helping species to maintain or expand their geographic distributions. The loss of these locally adapted range-edge populations through anthropogenic disturbance is therefore hypothesized to reduce the ability of species to persist in the face of rapid future climate change. PMID:26664681

  20. Computation of leading-edge vortex flows

    NASA Technical Reports Server (NTRS)

    Newsome, R. W.; Thomas, J. L.

    1986-01-01

    The simulation of the leading edge vortex flow about a series of conical delta wings through solution of the Navier-Stokes and Euler equations is studied. The occurrence, the validity, and the usefulness of separated flow solutions to the Euler equations of particular interest. Central and upwind difference solutions to the governing equations are compared for a series of cross sectional shapes, including both rounded and sharp tip geometries. For the rounded leading edge and the flight condition considered, viscous solutions obtained with either central or upwind difference methods predict the classic structure of vortical flow over a highly swept delta wing. Predicted features include the primary vortex due to leading edge separation and the secondary vortex due to crossflow separation. Central difference solutions to the Euler equations show a marked sensitivity to grid refinement. On a coarse grid, the flow separates due to numerical error and a primary vortex which resembles that of the viscous solution is predicted. In contrast, the upwind difference solutions to the Euler equations predict attached flow even for first-order solutions on coarse grids. On a sufficiently fine grid, both methods agree closely and correctly predict a shock-curvature-induced inviscid separation near the leeward plane of symmetry. Upwind difference solutions to the Navier-Stokes and Euler equations are presented for two sharp leading edge geometries. The viscous solutions are quite similar to the rounded leading edge results with vortices of similar shape and size. The upwind Euler solutions predict attached flow with no separation for both geometries. However, with sufficient grid refinement near the tip or through the use of more accurate spatial differencing, leading edge separation results. Once the leading edge separation is established, the upwind solution agrees with recently published central difference solutions to the Euler equations.

  1. Cloud deposition to a spruce forest edge

    NASA Astrophysics Data System (ADS)

    Weathers, K. C.; Lovett, G. M.; Likens, G. E.

    Deposition from clouds to a spruce (Picea rubens Sarg.) forest edge on Hunter Mt. in the Catskill Mts of New York State was measured during 1987 and 1988 to determine whether the windward edge of forest floor receives greater deposition of water and ions via cloud water than the interior of a forest. Throughfall was used as a measure of deposition and was collected during cloud-only and mixed cloud-and-rain events along five windward-to-leeward transects in a 30 x 30 m forested area. Ambient cloud water was also collected in a passive collector and chemically analyzed. Trees at the edge of the forest received on average three times, and up to 15 times, greater deposition of ions than those in the interior of the forest. Lead content in samples from Hunter Mt. forest floor at the windward edge, relative to the interior, was enhanced as well. Using a regression of distance vs deposition, the deposition "half-distance", (i.e. the point at which the rate of cloud water deposition is 50% of the rate at the windward edge of the forest) was found to be 28 m. The cloud deposition data from this study are compared to other studies of Na particle deposition to low-elevation forest edges, which show similar deposition "half distances", ranging from ˜ 2 to 36 m into the forest. Most models of cloud deposition currently in use assume landscape homogeneity. Montane forest landscapes, however, are often highly heterogeneous, consisting of many "edges", and thus current models may seriously underestimate cloud deposition.

  2. LT-STM/STS studies of clean armchair edge

    NASA Astrophysics Data System (ADS)

    Ju, Zheng; Zhang, Wenhan; Wu, Weida; Weida Wu Team

    It was predicted and observed that the passivated zigzag edges of graphene host highly localized edge state. This edge state is predicted to be spin-polarized, which is appealing for spintronic applications. In contrast, no edge state was expected at passivated armchair graphene edge. Here we report low temperature scanning tunneling microscopy and spectroscopy (STM/STS) studies of electronic properties of clean monoatomic step edges on cleaved surface of HOPG. Most of step edges are armchair edges, in agreement with previous STM results. We observed only (√{ 3} ×√{ 3}) R30° superstructure near armchair edges, which has been reported in previous STM studies. On the other hand, no honeycomb superstructure was observed in our STM data. In addition, our STM results reveal an intriguing localized electronic state at clean armchair edges. Spectroscopic and spatial evolution of this edge state will be presented. This work is supported by NSF DMR-1506618.

  3. Power spectrum weighted edge analysis for straight edge detection in images

    NASA Astrophysics Data System (ADS)

    Karvir, Hrishikesh V.; Skipper, Julie A.

    2007-04-01

    Most man-made objects provide characteristic straight line edges and, therefore, edge extraction is a commonly used target detection tool. However, noisy images often yield broken edges that lead to missed detections, and extraneous edges that may contribute to false target detections. We present a sliding-block approach for target detection using weighted power spectral analysis. In general, straight line edges appearing at a given frequency are represented as a peak in the Fourier domain at a radius corresponding to that frequency, and a direction corresponding to the orientation of the edges in the spatial domain. Knowing the edge width and spacing between the edges, a band-pass filter is designed to extract the Fourier peaks corresponding to the target edges and suppress image noise. These peaks are then detected by amplitude thresholding. The frequency band width and the subsequent spatial filter mask size are variable parameters to facilitate detection of target objects of different sizes under known imaging geometries. Many military objects, such as trucks, tanks and missile launchers, produce definite signatures with parallel lines and the algorithm proves to be ideal for detecting such objects. Moreover, shadow-casting objects generally provide sharp edges and are readily detected. The block operation procedure offers advantages of significant reduction in noise influence, improved edge detection, faster processing speed and versatility to detect diverse objects of different sizes in the image. With Scud missile launcher replicas as target objects, the method has been successfully tested on terrain board test images under different backgrounds, illumination and imaging geometries with cameras of differing spatial resolution and bit-depth.

  4. Partnership for Edge Physics Simulation (EPSI)

    SciTech Connect

    Schroder, Peter

    2015-02-11

    We propose to develop advanced simulation codes, based upon an extreme parallelism, first principles kinetic approach, to address the challenges associated with the edge region of magnetically confined plasmas. This work is relevant to both existing magnetic fusion facilities and essential for next-generation burning plasma experiments, such as ITER where success is critically dependent upon H-mode operation achieving an edge pedestal of sufficient height for good core plasma performance without producing deleterious large scale edge localized instabilities. The plasma edge presents a well-known set of multi-physics, multi-scale problems involving complex 3D magnetic geometry. Perhaps the greatest computational challenge is the lack of scale separation – temporal scales for drift waves, Alfven waves, ELM dynamics for example have strong overlap. Similar overlap occurs on the spatial scales for the ion poloidal gyro-radius, drift wave and pedestal width. The traditional approach of separating fusion problems into weakly interacting spatial or temporal domains clearly breaks down in the edge. A full kinetic model (full-f model) must be solved to understand and predict the edge physics including non-equilibrium thermodynamic issues arising from the magnetic topology (the open field lines producing a spatially sensitive velocity hole), plasma wall interactions, neutral and atomic physics. The plan here is to model these phenomena within a comprehensive first principles set of equations without the need for the insurmountable multiple-codes coupling issues by building on the XGC1 code developed under the SciDAC Proto-FSP Center for Plasma Edge Simulation (CPES). This proposal includes the critical participants in the XGC1 development. We propose enhancing the capability of XGC1 by including all the important turbulence physics contained in kinetic ion and electron electromagnetic dynamics, by extending the PIC technology to incorporate several positive features found

  5. Flap Edge Aeroacoustic Measurements and Predictions

    NASA Technical Reports Server (NTRS)

    Brooks, Thomas F.; Humphreys, William M., Jr.

    2000-01-01

    An aeroacoustic model test has been conducted to investigate the mechanisms of sound generation on high-lift wing configurations. This paper presents an analysis of flap side-edge noise, which is often the most dominant source. A model of a main element wing section with a half-span flap was tested at low speeds of up to a Mach number of 0.17, corresponding to a wing chord Reynolds number of approximately 1.7 million. Results are presented for flat (or blunt), flanged, and round flap-edge geometries, with and without boundary-layer tripping, deployed at both moderate and high flap angles. The acoustic database is obtained from a Small Aperture Directional Array (SADA) of microphones, which was constructed to electronically steer to different regions of the model and to obtain farfield noise spectra and directivity from these regions. The basic flap-edge aerodynamics is established by static surface pressure data, as well as by Computational Fluid Dynamics (CFD) calculations and simplified edge flow analyses. Distributions of unsteady pressure sensors over the flap allow the noise source regions to be defined and quantified via cross-spectral diagnostics using the SADA output. It is found that shear layer instability and related pressure scatter is the primary noise mechanism. For the flat edge flap, two noise prediction methods based on unsteady-surface-pressure measurements are evaluated and compared to measured noise. One is a new causality spectral approach developed here. The other is a new application of an edge-noise scatter prediction method. The good comparisons for both approaches suggest that much of the physics is captured by the prediction models. Areas of disagreement appear to reveal when the assumed edge noise mechanism does not fully define, the noise production. For the different edge conditions, extensive spectra and directivity are presented. Significantly, for each edge configuration, the spectra for different flow speeds, flap angles, and

  6. Image sharpness function based on edge feature

    NASA Astrophysics Data System (ADS)

    Jun, Ni

    2009-11-01

    Autofocus technique has been widely used in optical tracking and measure system, but it has problem that when the autofocus device should to work. So, no-reference image sharpness assessment has become an important issue. A new Sharpness Function that can estimate current frame image be in focus or not is proposed in this paper. According to current image whether in focus or not and choose the time of auto focus automatism. The algorithm measures object typical edge and edge direction, and then get image local kurtosis information to determine the degree of image sharpness. It firstly select several grads points cross the edge line, secondly calculates edge sharpness value and get the cure of the kurtosis, according the measure precision of optical-equipment, a threshold value will be set beforehand. If edge kurtosis value is more than threshold, it can conclude current frame image is in focus. Otherwise, it is out of focus. If image is out of focus, optics system then takes autofocus program. This algorithm test several thousands of digital images captured from optical tracking and measure system. The results show high correlation with subjective sharpness assessment for s images of sky object.

  7. Trailing edge modifications for flatback airfoils.

    SciTech Connect

    Kahn, Daniel L.; van Dam, C.P.; Berg, Dale E.

    2008-03-01

    The adoption of blunt trailing edge airfoils (also called flatback airfoils) for the inboard region of large wind turbine blades has been proposed. Blunt trailing edge airfoils would not only provide a number of structural benefits, such as increased structural volume and ease of fabrication and handling, but they have also been found to improve the lift characteristics of thick airfoils. Therefore, the incorporation of blunt trailing edge airfoils would allow blade designers to more freely address the structural demands without having to sacrifice aerodynamic performance. These airfoils do have the disadvantage of generating high levels of drag as a result of the low-pressure steady or periodic flow in the near-wake of the blunt trailing edge. Although for rotors, the drag penalty appears secondary to the lift enhancement produced by the blunt trailing edge, high drag levels are of concern in terms of the negative effect on the torque and power generated by the rotor. Hence, devices are sought that mitigate the drag of these airfoils. This report summarizes the literature on bluff body vortex shedding and bluff body drag reduction devices and proposes four devices for further study in the wind tunnel.

  8. Universal edge information from wavefunction deformation

    NASA Astrophysics Data System (ADS)

    Ho, Wen Wei; Cincio, Lukasz; Moradi, Heidar; Vidal, Guifre

    It is well known that the bulk physics of a topological phase constrains its possible edge physics through the bulk-edge correspondence. Therefore, the different types of edge theories that a topological phase can host is a universal piece of data which can be used to characterize topological order. Here, we argue that beginning from only the fixed point wavefunction (FPW) of a nonchiral topological phase and by locally deforming it, all possible edge theories can be extracted from its entanglement Hamiltonian (EH). We illustrate our claim by deforming the FPW of the Wen-plaquette model, the quantum double of ℤ2. We show that the possible EHs of the deformed FPWs reflect the known possible types of edge theories, which are generically gapped, but gapless if translational symmetry is preserved. We stress that our results do not require an underlying Hamiltonian - thus, this lends support to the notion that a topological phase is indeed characterized by only a set of quantum states and can be studied through its FPWs. Also affiliated to Perimeter Inst for Theo Phys.

  9. New analytic formula for edge bootstrap current

    NASA Astrophysics Data System (ADS)

    Chang, C. S.; Koh, S.; Menard, J.; Weitzner, H.; Choe, W.

    2012-10-01

    The edge bootstrap current plays a critical role in the equilibrium and stability of the steep edge pedestal plasma. The pedestal plasma has an unconventional and difficult neoclassical property, as compared with the core plasma. A drift-kinetic particle code XGC0, equipped with a mass-momentum-energy conserving collision operator, is used to study the edge bootstrap current in a realistic diverted magnetic field geometry with a self-consistent radial electric field. When the edge electrons are in the low collisionality banana regime, surprisingly, the present kinetic simulation confirms that the existing analytic expressions (represented by O. Sauter, et. al., Phys. Plasmas 6, 1999) are still valid in this unconventional region, except in a thin radial layer in contact with the magnetic separatrix. However, when the pedestal electrons are in plateau-collisional regime, there is a significant deviation of numerical results from the existing analytic formulas. The deviation occurs in different ways between a conventional aspect ratio tokamak and a tight aspect ratio tokamak. A new analytic fitting formula, as a simple modification to the Sauter formula, is obtained to bring the analytic expression to a better agreement with the edge kinetic simulation results.

  10. Image enhancement based on edge boosting algorithm

    NASA Astrophysics Data System (ADS)

    Ngernplubpla, Jaturon; Chitsobhuk, Orachat

    2015-12-01

    In this paper, a technique for image enhancement based on proposed edge boosting algorithm to reconstruct high quality image from a single low resolution image is described. The difficulty in single-image super-resolution is that the generic image priors resided in the low resolution input image may not be sufficient to generate the effective solutions. In order to achieve a success in super-resolution reconstruction, efficient prior knowledge should be estimated. The statistics of gradient priors in terms of priority map based on separable gradient estimation, maximum likelihood edge estimation, and local variance are introduced. The proposed edge boosting algorithm takes advantages of these gradient statistics to select the appropriate enhancement weights. The larger weights are applied to the higher frequency details while the low frequency details are smoothed. From the experimental results, the significant performance improvement quantitatively and perceptually is illustrated. It can be seen that the proposed edge boosting algorithm demonstrates high quality results with fewer artifacts, sharper edges, superior texture areas, and finer detail with low noise.

  11. Numerical simulation of the edge tone phenomenon

    NASA Technical Reports Server (NTRS)

    Dougherty, N. S.; Liu, B. L.; Ofarrell, J. M.

    1994-01-01

    Time accurate Navier-Stokes computations were performed to study a class 2 (acoustic) whistle, the edge tone, and to gain knowledge of the vortex-acoustic coupling mechanisms driving production of these tones. Results were obtained by solving the full Navier-Stokes equations for laminar compressible air flow of a two dimensional jet issuing from a slit interacting with a wedge. Cases considered were determined by varying the distance from the slit to the wedge. Flow speed was kept constant at 1,750 cm/s as was the slit thickness of 0.1 cm, corresponding to conditions in the experiments of Brown. The analytical computations revealed edge tones to be present in four harmonic stages of jet flow instability over the wedge as the jet length was varied from 0.3 to 1.6 cm. Excellent agreement was obtained in all four edge tone stage cases between the present computational results and the experimentally obtained frequencies and flow visualization results of Brown. Specific edge tone generation phenomena and further confirmation of certain theories and empirical formulas concerning these phenomena were brought to light in this analytical simulation of edge tones.

  12. Edge printability: techniques used to evaluate and improve extreme wafer edge printability

    NASA Astrophysics Data System (ADS)

    Roberts, Bill; Demmert, Cort; Jekauc, Igor; Tiffany, Jason P.

    2004-05-01

    The economics of semiconductor manufacturing have forced process engineers to develop techniques to increase wafer yield. Improvements in process controls and uniformities in all areas of the fab have reduced film thickness variations at the very edge of the wafer surface. This improved uniformity has provided the opportunity to consider decreasing edge exclusions, and now the outermost extents of the wafer must be considered in the yield model and expectations. These changes have increased the requirements on lithography to improve wafer edge printability in areas that previously were not even coated. This has taxed all software and hardware components used in defining the optical focal plane at the wafer edge. We have explored techniques to determine the capabilities of extreme wafer edge printability and the components of the systems that influence this printability. We will present current capabilities and new detection techniques and the influence that the individual hardware and software components have on edge printability. We will show effects of focus sensor designs, wafer layout, utilization of dummy edge fields, the use of non-zero overlay targets and chemical/optical edge bead optimization.

  13. General-purpose adaptive edge detector based on an empirical edge model

    SciTech Connect

    Breedlove, J.R. Jr.; Cantoni, V.

    1982-01-01

    We present a new approach to computer edge detection for image mensuration. Our technique uses data from the actual image to build an edge-detector template for a matched filtering algorithm. We show that the procedure is superior to classical, template matching techniques for a computer-generated image and for a very noisy x-ray image.

  14. Diagnosing Topological Edge States via Entanglement Monogamy.

    PubMed

    Meichanetzidis, K; Eisert, J; Cirio, M; Lahtinen, V; Pachos, J K

    2016-04-01

    Topological phases of matter possess intricate correlation patterns typically probed by entanglement entropies or entanglement spectra. In this Letter, we propose an alternative approach to assessing topologically induced edge states in free and interacting fermionic systems. We do so by focussing on the fermionic covariance matrix. This matrix is often tractable either analytically or numerically, and it precisely captures the relevant correlations of the system. By invoking the concept of monogamy of entanglement, we show that highly entangled states supported across a system bipartition are largely disentangled from the rest of the system, thus, usually appearing as gapless edge states. We then define an entanglement qualifier that identifies the presence of topological edge states based purely on correlations present in the ground states. We demonstrate the versatility of this qualifier by applying it to various free and interacting fermionic topological systems.

  15. Preparation of edge states by shaking boundaries

    NASA Astrophysics Data System (ADS)

    Shi, Z. C.; Hou, S. C.; Wang, L. C.; Yi, X. X.

    2016-10-01

    Preparing topological states of quantum matter, such as edge states, is one of the most important directions in condensed matter physics. In this work, we present a proposal to prepare edge states in Aubry-André-Harper (AAH) model with open boundaries, which takes advantage of Lyapunov control to design operations. We show that edge states can be obtained with almost arbitrary initial states. A numerical optimalization for the control is performed and the dependence of control process on the system size is discussed. The merit of this proposal is that the shaking exerts only on the boundaries of the model. As a by-product, a topological entangled state is achieved by elaborately designing the shaking scheme.

  16. Acoustic metamaterial for subwavelength edge detection

    PubMed Central

    Molerón, Miguel; Daraio, Chiara

    2015-01-01

    Metamaterials have demonstrated the possibility to produce super-resolved images by restoring propagative and evanescent waves. However, for efficient information transfer, for example, in compressed sensing, it is often desirable to visualize only the fast spatial variations of the wave field (carried by evanescent waves), as the one created by edges or small details. Image processing edge detection algorithms perform such operation, but they add time and complexity to the imaging process. Here we present an acoustic metamaterial that transmits only components of the acoustic field that are approximately equal to or smaller than the operating wavelength. The metamaterial converts evanescent waves into propagative waves exciting trapped resonances, and it uses periodicity to attenuate the propagative components. This approach achieves resolutions ∼5 times smaller than the operating wavelength and makes it possible to visualize independently edges aligned along different directions. PMID:26304739

  17. Floquet edge states in germanene nanoribbons

    PubMed Central

    Tahir, M.; Zhang, Q. Y.; Schwingenschlögl, U.

    2016-01-01

    We theoretically demonstrate versatile electronic properties of germanene monolayers under circularly, linearly, and elliptically polarized light. We show for the high frequency regime that the edge states can be controlled by tuning the amplitude of the light and by applying a static electric field. For circularly polarized light the band gap in one valley is reduced and in the other enhanced, enabling single valley edge states. For linearly polarized light spin-split states are found for both valleys, being connected by time reversal symmetry. The effects of elliptically polarized light are similar to those of circularly polarized light. The transport properties of zigzag nanoribbons in the presence of disorder confirm a nontrivial nature of the edge states under circularly and elliptically polarized light. PMID:27550632

  18. Floquet edge states in germanene nanoribbons.

    PubMed

    Tahir, M; Zhang, Q Y; Schwingenschlögl, U

    2016-01-01

    We theoretically demonstrate versatile electronic properties of germanene monolayers under circularly, linearly, and elliptically polarized light. We show for the high frequency regime that the edge states can be controlled by tuning the amplitude of the light and by applying a static electric field. For circularly polarized light the band gap in one valley is reduced and in the other enhanced, enabling single valley edge states. For linearly polarized light spin-split states are found for both valleys, being connected by time reversal symmetry. The effects of elliptically polarized light are similar to those of circularly polarized light. The transport properties of zigzag nanoribbons in the presence of disorder confirm a nontrivial nature of the edge states under circularly and elliptically polarized light. PMID:27550632

  19. Development of Columbia Leading Edge Reconstruction System

    NASA Technical Reports Server (NTRS)

    Trautwein, John; Wegerif, Dan

    2004-01-01

    After the loss of Columbia in 2003, the Columbia Accident Investigation Board and NASA KSC directed personnel at the Launch Equipment Test Facility (LETF) to design and build high fidelity mock-ups of Columbia's left wing leading edges. These leading edge segments, constructed of reinforced carbon-carbon, were a major point of inquiry by the investigation team. The LETF engineers developed a concept of building a clear Lexan panel with an aluminum support structure ten percent larger than the original panel. The leading edge debris are attached to the Lexan panels and both the front and back side of each panel are visible for inspection. The entire assembly can be rotated, to provide visual access to the entire panel. Six carts were fabricated to support the thirteen panels. These carts could be set up in order, next to each other, to provide the desired inspection access. The carts and attached debris are currently located in the Vehicle Assembly Building at KSC.

  20. Edge Detection By Differences Of Gaussians

    NASA Astrophysics Data System (ADS)

    Marthon, Ph.; Thiesse, B.; Bruel, A.

    1986-06-01

    The Differences of Gaussians (DOGs) are of fundamental importance in edge detection. They belong to the human vision system as shown by Enroth-Cugell and Robson [ENR66]. The zero-crossings of their outputs mark the loci of the intensity changes. The set of descriptions from different operator sizes forms the input for later visual processes, such as stereopsis and motion analysis. We show that DOGs uniformly converge to the Laplacian of a Gaussian (ΔG2,σ) when both the inhibitory and excitatory variables converge to σ. Spatial and spectral properties of DOGs and ΔGs are compared: width and height of their central positive regions, bandiwidths... Finally, DOGs' responses to some features such as ideal edge, right angle corner, general corner..., are presented and magnitudes of error on edge position are given.

  1. Heuristic edge detector for noisy range images

    NASA Astrophysics Data System (ADS)

    Wu, Kung C.

    1994-10-01

    This paper presents a heuristic edge detector for extracting wireframe representations of objects from noisy range data. Jump and roof edges were detected successfully from range images containing additive white Gaussian noise with a standard deviation equal to as high as 1.2% of the measured range values. This represents an appreciable amount of noise since approximately 5% of the errors are greater than 12 cm and 32% of errors are greater than 6 cm at a distance of 5 meters. The noise insensitive characteristic of the heuristic edge detector enables low cost range scanners to be used for practical industrial applications. The availability of low cost active vision systems greatly broadens the horizon of integrating robotics vision systems to manufacturing automation.

  2. Edge excitations in fractional Chern insulators

    NASA Astrophysics Data System (ADS)

    Luo, Wei-Wei; Chen, Wen-Chao; Wang, Yi-Fei; Gong, Chang-De

    2013-10-01

    Recent theoretical papers have demonstrated the realization of fractional quantum anomalous Hall states (also called fractional Chern insulators) in topological flat band lattice models without an external magnetic field. Such newly proposed lattice systems play a vital role in obtaining a large class of fractional topological phases. Here we report the exact numerical studies of edge excitations for such systems in a disk geometry loaded with hard-core bosons, which will serve as a more viable experimental probe for such topologically ordered states. We find convincing numerical evidence of a series of edge excitations characterized by the chiral Luttinger liquid theory for the bosonic fractional Chern insulators in both the honeycomb disk Haldane model and the kagome-lattice disk model. We further verify these current-carrying chiral edge states by inserting a central flux to test their compressibility.

  3. Black phosphorus edges: a polarized Raman study

    NASA Astrophysics Data System (ADS)

    Ribeiro, H.; Villegas, C.; Bahamon, D.; Castro Neto, A.; de Souza, E.; Rocha, A.; Pimenta, M.; de Matos, C.

    Black phosphorus (BP) has been recently exfoliated down to few-layer thicknesses revealing numerous interesting features such as a tunable direct bandgap. Ever since, demonstrations of BP electronic devices have bloomed, as well as studies of the electric, optical, mechanical and thermal properties of its bulk and few-layer forms. However, the edges of BP crystals have, so far, been poorly characterized, even though the terminations of layered crystals are known to possess a range of interesting properties. In this work, the edges of exfoliated BP flakes are characterized by polarized confocal Raman spectroscopy. We will present experimental Raman spectra at zigzag and armchair edges, as well as density functional theory calculations that explain the peculiarities of the experimental data. Fapesp, INCT/Nanocarbono, Fapemig, CNPq, MackPesquisa, Grid-Unesp, CENAPAD-SP, and NRF.

  4. Floquet edge states in germanene nanoribbons

    NASA Astrophysics Data System (ADS)

    Tahir, M.; Zhang, Q. Y.; Schwingenschlögl, U.

    2016-08-01

    We theoretically demonstrate versatile electronic properties of germanene monolayers under circularly, linearly, and elliptically polarized light. We show for the high frequency regime that the edge states can be controlled by tuning the amplitude of the light and by applying a static electric field. For circularly polarized light the band gap in one valley is reduced and in the other enhanced, enabling single valley edge states. For linearly polarized light spin-split states are found for both valleys, being connected by time reversal symmetry. The effects of elliptically polarized light are similar to those of circularly polarized light. The transport properties of zigzag nanoribbons in the presence of disorder confirm a nontrivial nature of the edge states under circularly and elliptically polarized light.

  5. Iowa Journal of School Social Work, 1994-1998.

    ERIC Educational Resources Information Center

    McCullagh, Cheryl, Ed.; Froyen, Gary, Ed.

    1998-01-01

    This publication of the Iowa State School Workers' Association is dedicated to the enhancement of social work practice in schools. Within the social work profession, school social workers may find themselves on the cutting edge and forefront of issues affecting students. The articles in these journals attempt to provide comprehensive knowledge…

  6. More than Money Matters: Establishing Effective School-Corporate Partnerships

    ERIC Educational Resources Information Center

    Flynn, Nancy

    2007-01-01

    Given the financial constraints facing U.S. schools and the expense of cutting-edge technology, partnerships between schools and corporations that specialize in technology are becoming more vital in the quest to remain competitive in today's educational market. Schools can benefit from these partnerships by receiving the latest hardware and…

  7. Airplane wing leading edge variable camber flap

    NASA Technical Reports Server (NTRS)

    Cole, J. B.

    1980-01-01

    The invention and design of an aerodynamic high lift device which provided a solution to an aircraft performance problem are described. The performance problem of converting a high speed cruise airfoil into a low speed aerodynamic shape that would provide landing and take-off characteristics superior to those available with contemporary high lift devices are addressed. The need for an improved wing leading edge device that would complement the high lift performance of a triple slotted trailing edge flap is examined. The mechanical and structural aspects of the variable camber flap are discussed and the aerodynamic performance aspects only as they relate to the invention and design of the device are presented.

  8. Edge Mode Coupling within a Plasmonic Nanoparticle

    PubMed Central

    2016-01-01

    The coupling of plasmonic nanoparticles can strongly modify their optical properties. Here, we show that the coupling of the edges within a single rectangular particle leads to mode splitting and the formation of bonding and antibonding edge modes. We are able to unambiguously designate the modes due to the high spatial resolution of electron microscopy-based electron energy loss spectroscopy and the comparison with numerical simulations. Our results provide simple guidelines for the interpretation and the design of plasmonic mode spectra. PMID:27427962

  9. Edge detection techniques for iris recognition system

    NASA Astrophysics Data System (ADS)

    Tania, U. T.; Motakabber, S. M. A.; Ibrahimy, M. I.

    2013-12-01

    Nowadays security and authentication are the major parts of our daily life. Iris is one of the most reliable organ or part of human body which can be used for identification and authentication purpose. To develop an iris authentication algorithm for personal identification, this paper examines two edge detection techniques for iris recognition system. Between the Sobel and the Canny edge detection techniques, the experimental result shows that the Canny's technique has better ability to detect points in a digital image where image gray level changes even at slow rate.

  10. Edge states of periodically kicked quantum rotors.

    PubMed

    Floss, Johannes; Averbukh, Ilya Sh

    2015-05-01

    We present a quantum localization phenomenon that exists in periodically kicked three-dimensional rotors, but is absent in the commonly studied two-dimensional ones: edge localization. We show that under the condition of a fractional quantum resonance there are states of the kicked rotor that are strongly localized near the edge of the angular momentum space at J=0. These states are analogs of surface states in crystalline solids, and they significantly affect resonant excitation of molecular rotation by laser pulse trains.

  11. Near Field Trailing Edge Tone Noise Computation

    NASA Technical Reports Server (NTRS)

    Loh, Ching Y.

    2002-01-01

    Blunt trailing edges in a flow often generate tone noise due to wall-jet shear layer and vortex shedding. In this paper, the space-time conservation element (CE/SE) method is employed to numerically study the near-field noise of blunt trailing edges. Two typical cases, namely, flow past a circular cylinder (aeolian noise problem) and flow past a flat plate of finite thickness are considered. The computed frequencies compare well with experimental data. For the aeolian noise problem, comparisons with the results of other numerical approaches are also presented.

  12. Wing Leading Edge Concepts for Noise Reduction

    NASA Technical Reports Server (NTRS)

    Shmilovich, Arvin; Yadlin, Yoram; Pitera, David M.

    2010-01-01

    This study focuses on the development of wing leading edge concepts for noise reduction during high-lift operations, without compromising landing stall speeds, stall characteristics or cruise performance. High-lift geometries, which can be obtained by conventional mechanical systems or morphing structures have been considered. A systematic aerodynamic analysis procedure was used to arrive at several promising configurations. The aerodynamic design of new wing leading edge shapes is obtained from a robust Computational Fluid Dynamics procedure. Acoustic benefits are qualitatively established through the evaluation of the computed flow fields.

  13. Not Your Ordinary School Pictures

    ERIC Educational Resources Information Center

    Coy, Mary

    2007-01-01

    Although every parent loves the annual school portrait taken of their child, artistically, not much can be said about the photo's diversity from year to year, or from child to child. Sure, one can order a softened halo around the edge or even a laser effect shooting distractingly around in the background, but basically, one portrait is similar to…

  14. A new method of edge detection for object recognition

    USGS Publications Warehouse

    Maddox, Brian G.; Rhew, Benjamin

    2004-01-01

    Traditional edge detection systems function by returning every edge in an input image. This can result in a large amount of clutter and make certain vectorization algorithms less accurate. Accuracy problems can then have a large impact on automated object recognition systems that depend on edge information. A new method of directed edge detection can be used to limit the number of edges returned based on a particular feature. This results in a cleaner image that is easier for vectorization. Vectorized edges from this process could then feed an object recognition system where the edge data would also contain information as to what type of feature it bordered.

  15. Hybrid Schools for the iGeneration

    ERIC Educational Resources Information Center

    Schulte, Brigid

    2011-01-01

    Carpe Diem, a public charter school, is an entirely new type of school and one of only a handful of its kind in the U.S. They seek to combine the best of traditional, face-to-face instruction with the best cutting-edge online curriculum. The result is something education experts call a hybrid school. Instead of a traditional brick-and-mortar…

  16. Liquid-Crystal Light Valve Enhances Edges In Images

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin; Liu, Hua-Kuang

    1991-01-01

    Experiments show liquid-crystal light valve (LCLV) exhibits operating mode in which it enhances edges in images projected on it. Operates in edge-enhancing mode (or in combination of edge-enhancing and normal modes) by suitably adjusting bias voltage and frequency. Enhancement of edges one of most important preprocessing steps in optical pattern-recognition systems. Incorporated into image-processing system to enhance edges without introducing excessive optical noise.

  17. Superconducting Metallic Glass Transition-Edge-Sensors

    NASA Technical Reports Server (NTRS)

    Hays, Charles C. (Inventor)

    2013-01-01

    A superconducting metallic glass transition-edge sensor (MGTES) and a method for fabricating the MGTES are provided. A single-layer superconducting amorphous metal alloy is deposited on a substrate. The single-layer superconducting amorphous metal alloy is an absorber for the MGTES and is electrically connected to a circuit configured for readout and biasing to sense electromagnetic radiation.

  18. Apparatus for edge etching of semiconductor wafers

    NASA Technical Reports Server (NTRS)

    Casajus, A.

    1986-01-01

    A device for use in the production of semiconductors, characterized by etching in a rapidly rotating etching bath is described. The fast rotation causes the surface of the etching bath to assume the form of a paraboloid of revolution, so that the semiconductor wafer adjusted at a given height above the resting bath surface is only attacked by etchant at the edges.

  19. New applications of Spectral Edge image fusion

    NASA Astrophysics Data System (ADS)

    Hayes, Alex E.; Montagna, Roberto; Finlayson, Graham D.

    2016-05-01

    In this paper, we present new applications of the Spectral Edge image fusion method. The Spectral Edge image fusion algorithm creates a result which combines details from any number of multispectral input images with natural color information from a visible spectrum image. Spectral Edge image fusion is a derivative-based technique, which creates an output fused image with gradients which are an ideal combination of those of the multispectral input images and the input visible color image. This produces both maximum detail and natural colors. We present two new applications of Spectral Edge image fusion. Firstly, we fuse RGB-NIR information from a sensor with a modified Bayer pattern, which captures visible and near-infrared image information on a single CCD. We also present an example of RGB-thermal image fusion, using a thermal camera attached to a smartphone, which captures both visible and low-resolution thermal images. These new results may be useful for computational photography and surveillance applications.

  20. Helicopter rotor trailing edge noise. [noise prediction

    NASA Technical Reports Server (NTRS)

    Schlinker, R. H.; Amier, R. K.

    1981-01-01

    A two dimensional section of a helicopter main rotor blade was tested in an acoustic wind tunnel at close to full-scale Reynolds numbers to obtain boundary layer data and acoustic data for use in developing an acoustic scaling law and testing a first principles trailing edge noise theory. Results were extended to the rotating frame coordinate system to develop a helicopter rotor trailing edge noise prediction. Comparisons of the calculated noise levels with helicopter flyover spectra demonstrate that trailing edge noise contributes significantly to the total helicopter noise spectrum at high frequencies. This noise mechanism is expected to control the minimum rotor noise. In the case of noise radiation from a local blade segment, the acoustic directivity pattern is predicted by the first principles trailing edge noise theory. Acoustic spectra are predicted by a scaling law which includes Mach number, boundary layer thickness and observer position. Spectrum shape and sound pressure level are also predicted by the first principles theory but the analysis does not predict the Strouhal value identifying the spectrum peak.

  1. Students at the Edge of Space

    ERIC Educational Resources Information Center

    Kennon, Tillman; Roberts, Ed; Fuller, Teresa

    2008-01-01

    Space travel, even low Earth orbit, is probably several years away for most of us; however, students and teachers can research the edge of space by participating in the BalloonSat program. BalloonSat is an offshoot of the Space Grant Consortium's very successful RocketSat program. The Arkansas BalloonSat program consists of teacher-initiated…

  2. The Cognitive Dimension--"Edge of Darkness."

    ERIC Educational Resources Information Center

    McGuigan, Jim

    This paper discusses the cognitive effect of a highly successful 1985 British television program, "Edge of Darkness," which was viewed by millions and received critical plaudits and the accolade of the industry itself. The program is shown to represent a significant television event for formal and cognitive reasons that can usefully be related to…

  3. Strip edge cracking simulation in cold rolling

    SciTech Connect

    Hubert, C.; Dubar, L.; Dubar, M.; Dubois, A.

    2011-01-17

    This research work focuses on a specific defect which occurs during cold rolling of steel strips: edge-serration. Investigations on the industrial processes have led to the conclusion that this defect is the result of the edge-trimming and cold rolling sequences. The aim of this research work is to analyze the effect of the cutting process and the cold rolling on cracks occurrence, especially on strip edges.This study is performed using an experimental testing stand called Upsetting Rolling Test (URT). It allows to reproduce cold rolling contact parameters such as forward slip, reduction ratio and friction coefficients. Specimens sampled near trimmed industrial strip edges are deformed using the URT stand. Two sets of specimens with different stress states, obtained by annealing, are submitted to two reduction passes with extreme forward slips.Scanning electron microscopy observations added to 3D optical surface profiler topographies show that on one hand, forward slip has a major effect on cracks opening. On the other hand, cracks opening decreases according to high roll strip speed gradient. Concerning the heat-treated specimens, no crack appeared after all reduction passes, showing a large influence of the cutting process and consequently of the local stress state in the vicinity of the burnish and fracture regions.

  4. The Edges of the Ocean: An Introduction.

    ERIC Educational Resources Information Center

    Burke, Kevin

    1979-01-01

    Introduces a series of related articles on the study of ocean/continent boundaries (margins) within the framework of plate tectonics. Topics discussed include: early attempts to interpret ocean/continent boundaries, Atlantic-type margins, Pacific-type margins, the edges of ancient oceans, and future challenges in the study of continental margins.…

  5. Edge currents in frustrated Josephson junction ladders

    NASA Astrophysics Data System (ADS)

    Marques, A. M.; Santos, F. D. R.; Dias, R. G.

    2016-09-01

    We present a numerical study of quasi-1D frustrated Josephson junction ladders with diagonal couplings and open boundary conditions, in the large capacitance limit. We derive a correspondence between the energy of this Josephson junction ladder and the expectation value of the Hamiltonian of an analogous tight-binding model, and show how the overall superconducting state of the chain is equivalent to the minimum energy state of the tight-binding model in the subspace of one-particle states with uniform density. To satisfy the constraint of uniform density, the superconducting state of the ladder is written as a linear combination of the allowed k-states of the tight-binding model with open boundaries. Above a critical value of the parameter t (ratio between the intra-rung and inter-rung Josephson couplings) the ladder spontaneously develops currents at the edges, which spread to the bulk as t is increased until complete coverage is reached. Above a certain value of t, which varies with ladder size (t = 1 for an infinite-sized ladder), the edge currents are destroyed. The value t = 1 corresponds, in the tight-binding model, to the opening of a gap between two bands. We argue that the disappearance of the edge currents with this gap opening is not coincidental, and that this points to a topological origin for these edge current states.

  6. Social Justice as a Pedagogy of Edge

    ERIC Educational Resources Information Center

    Sonu, Debbie J.

    2010-01-01

    In this article, the author discusses social justice as a "pedagogy of edge." She argues that educators hold the privilege to begin reframing the dialogue on social justice as a relation of all subjects and to dredge from within the meanings drawn and practices made in honor of justice. This may require a shift away from social justice as a…

  7. The Cutting Edge, 1999-2000.

    ERIC Educational Resources Information Center

    Cutting Edge, 2000

    2000-01-01

    The Cutting Edge is a bimonthly newsletter of the Regional Center for Applied Technology and Training at Danville Community College (DCC) (Virginia) that provides the latest information on a wide range of issues including technology, business, employment trends, and new legislation. Articles from the first five issues discuss: (1) the July 2000…

  8. Diffraction Anomalous Near-Edge Structure

    NASA Astrophysics Data System (ADS)

    Moltaji, Habib O., Jr.

    1995-11-01

    To determine the atomic structure about atom of an element in a sample of a condensed multicomponent single crystal, contrast radiation is proposed with the use of Diffraction Anomalous Near-Edge Structure (DANES), which combines the long-range order sensitivity of the x-ray diffraction and short-range order of the x-ray absorption near-edge techniques. This is achieved by modulating the photon energy of the x-ray beam incident on the sample over a range of energies near an absorption edge of the selected element. Due to anomalous dispersion, x-ray diffraction, and x-ray absorption, the DANES intensity with respect to the selected element is obtained in a single experiment. I demonstrate that synchrotron DANES measurements for the single crystal of thin film and the powder samples and provide the same local atomic structural information as the x-ray absorption near-edge with diffraction condition and can be used to provide enhanced site selectivity. I demonstrate calculations of DAFS intensity and measurements of polarized DANES and XANES intensity.

  9. The Cutting Edge: Workplace English. Instructional Guide.

    ERIC Educational Resources Information Center

    El Paso Community Coll., TX. Literacy Center.

    The instructional guide for the Cutting Edge workplace literacy program, a cooperative project of El Paso Community College (Texas) and Levi Strauss and Company, is an expanded version of one appendix the project handbook. It describes and provides an instructional model for the three-part, job-specific, video-based program of English as a Second…

  10. Acoustic streaming of a sharp edge.

    PubMed

    Ovchinnikov, Mikhail; Zhou, Jianbo; Yalamanchili, Satish

    2014-07-01

    Anomalous acoustic streaming is observed emanating from sharp edges of solid bodies that are vibrating in fluids. The streaming velocities can be orders of magnitude higher than expected from the Rayleigh streaming at similar amplitudes of vibration. Acoustic velocity of fluid relative to a solid body diverges at a sharp edge, giving rise to a localized time-independent body force acting on the fluid. This force results in a formation of a localized jet. Two-dimensional numerical simulations are performed to predict acoustic streaming for low amplitude vibration using two methods: (1) Steady-state solution utilizing perturbation theory and (2) direct transient solution of the Navier-Stokes equations. Both analyses agree with each other and correctly predict the streaming of a sharp-edged vibrating blade measured experimentally. The origin of the streaming can be attributed to the centrifugal force of the acoustic fluid flow around a sharp edge. The dependence of this acoustic streaming on frequency and velocity is examined using dimensional analysis. The dependence law is devised and confirmed by numerical simulations.

  11. Directed triadic closure and edge deletion mechanism induce asymmetry in directed edge properties

    NASA Astrophysics Data System (ADS)

    Brot, Hilla; Muchnik, Lev; Louzoun, Yoram

    2015-01-01

    Many directed real world networks, such as the WWW, genetic regulation networks and economic networks exhibit significant differences between the properties of the incoming and outgoing edges, while the differences exhibited by other networks, such as Social Netw. are far more limited. This phenomenon is most evident in the differences between the distributions of incoming and outgoing degrees and direct clustering coefficients. There is currently no generic network generation model that would reproduce and tune these observed dissimilarities. We propose and empirically validate a simple and realistic model that can explain the emergence of the dissimilarities between the incoming and outgoing network degrees and clustering coefficients by combining directed triadic closure, random edge addition and directed edge removal. Surprisingly, we find that the difference between in and out degree distributions is attributed to asymmetries in the edge removal, highlighting the neglected yet crucial importance of edge removal mechanisms to the static and dynamic properties of real world networks. The model is governed by only two parameters: the first tunes the randomness of the edge addition mechanism, while the second controls the difference between the in and out degrees. The combination of these parameters reproduces the observed variety of directed degree distributions and clustering coefficients. Further comparisons of the model's microscopic dynamics against the empirically observed evolution of real world social network confirms that while quite simple, the model properly describes both the edge addition and deletion processes in directed networks.

  12. Tangential 2-D Edge Imaging for GPI and Edge/Impurity Modeling

    SciTech Connect

    Dr. Ricardo Maqueda; Dr. Fred M. Levinton

    2011-12-23

    Nova Photonics, Inc. has a collaborative effort at the National Spherical Torus Experiment (NSTX). This collaboration, based on fast imaging of visible phenomena, has provided key insights on edge turbulence, intermittency, and edge phenomena such as edge localized modes (ELMs) and multi-faceted axisymmetric radiation from the edge (MARFE). Studies have been performed in all these areas. The edge turbulence/intermittency studies make use of the Gas Puff Imaging diagnostic developed by the Principal Investigator (Ricardo Maqueda) together with colleagues from PPPL. This effort is part of the International Tokamak Physics Activity (ITPA) edge, scrape-off layer and divertor group joint activity (DSOL-15: Inter-machine comparison of blob characteristics). The edge turbulence/blob study has been extended from the current location near the midplane of the device to the lower divertor region of NSTX. The goal of this effort was to study turbulence born blobs in the vicinity of the X-point region and their circuit closure on divertor sheaths or high density regions in the divertor. In the area of ELMs and MARFEs we have studied and characterized the mode structure and evolution of the ELM types observed in NSTX, as well as the study of the observed interaction between MARFEs and ELMs. This interaction could have substantial implications for future devices where radiative divertor regions are required to maintain detachment from the divertor plasma facing components.

  13. Careful Planning: The Fundraising Edge [and] A Twelve-Step Program for Stronger Grant Proposals [and] Business-School Partnerships: Future Media Center Funding Sources [and] Rakin' in the Clams... Or, How to Make Lots of Cash from Renting Best-Sellers [and] The Book Business: The Bookstore as an Alternative Funding Source for the Public Library [and] Friends of the Library Book Sales.

    ERIC Educational Resources Information Center

    Sumerford, Steve; And Others

    1995-01-01

    Presents six articles addressing various methods and concerns for raising funds for public, academic, and school libraries, including raising money from corporations, foundations, and individuals; the process of writing grant proposals; local business/school partnerships; rental programs for bestsellers; bookstores/giftshops; and friends of the…

  14. Automated edge detection versus manual edge measurement in analysis of brachial artery reactivity: a comparison study.

    PubMed

    Williamson, Eric B; Bronas, Ulf G; Dengel, Donald R

    2008-09-01

    High resolution ultrasound, combined with computer imaging technology, is commonly used to measure changes in brachial artery diameter for the determination of endothelial-dependent vasodilation (EDD) and endothelial independent-vasodilation (EID). Currently, two methods of computerized edge-detection systems are in use to measure changes in artery diameter. One system involves the sonographer manually tracking the artery walls while the second system involves a computer automated edge-detection system that automatically tracks the artery wall. The purpose of this study was to compare the two types of computerized edge-detection systems for measuring vascular function and structure. One hundred fifty (female = 70, male = 80) participants agreed to participate. Baseline brachial diameter, carotid intima-medial thickness (cIMT), EDD and EID were measured by the two computerized edge-detection systems utilizing the same ultrasound B-mode image. Mean values (+/-standard error) for baseline diameter, cIMT, EDD and EID were 3.53 (+/-0.10) mm, 0.43 (+/-0.01) mm, 5.72 (+/-0.20)% and 22.17 (+/-0.60)%, respectively for the manual edge-detection software system. Mean values for baseline diameter, cIMT, EDD and EID were 3.59 (+/-0.10) mm, 0.44 (+/-0.01) mm, 7.33 (+/-0.30)% and 25.77 (+/-0.60)%, respectively for the automated edge-detection software system. Bland-Altman plots displayed large variations between the two edge-detection methods for assessing cIMT and changes in artery diameter following brachial EDD and EID. The results of the study demonstrate that manual and automated computerized edge-detection systems track dynamic changes in brachial artery diameter and cIMT measures differently. Therefore, caution should be used when comparing research utilizing different computerized edge-detection systems for measuring vascular function and structure.

  15. A Theory of Oscillating Edge Flames

    NASA Technical Reports Server (NTRS)

    Buckmaster, J.; Zhang, Yi

    1999-01-01

    It has been known for some years that when a near-limit flame spreads over a liquid pool of fuel, the edge of the flame can oscillate relative to a frame moving with the mean speed. Each period of oscillation is characterized by long intervals of modest motion during which the edge gases radiate like those of a diffusion flame, punctuated by bursts of rapid advance during which the edge gases radiate like those in a deflagration. Substantial resources have been brought to bear on this issue within the microgravity program, both experimental and numerical. It is also known that when a near-asphyxiated candle-flame burns at zero gravity, the edge of the (hemispherical) flame can oscillate violently prior to extinction. Thus a web-surfer, turning to the NASA web-site at http://microgravity.msfc.nasa.gov, and following the trail combustion science/experiments/experimental results/candle flame, will find photographs and a description of candle burning experiments carried out on board both the Space-shuttle and the Russian space station Mir. A brief report can also be found in the proceedings of the Fourth Workshop. And recently, in a third microgravity program, the leading edge of the flame supported by injection of ethane through the porous surface of a plate over which air is blown has been found to oscillate when conditions are close to blow-off. A number of important points can be made with respect to these observations: It is the edge itself which oscillates, advancing and retreating, not the diffusion flame that trails behind the edge; oscillations only occur under near limit conditions; in each case the Lewis number of the fuel is significantly larger than 1; and because of the edge curvature, the heat losses from the reacting edge structure are larger than those from the trailing diffusion flame. We propose a general theory for these oscillations, invoking Occam's 'Law of Parsimony' in an expanded form, to wit: The same mechanism is responsible for the

  16. Mapping Forest Edge Using Aerial Lidar

    NASA Astrophysics Data System (ADS)

    MacLean, M. G.

    2014-12-01

    Slightly more than 60% of Massachusetts is covered with forest and this land cover type is invaluable for the protection and maintenance of our natural resources and is a carbon sink for the state. However, Massachusetts is currently experiencing a decline in forested lands, primarily due to the expansion of human development (Thompson et al., 2011). Of particular concern is the loss of "core areas" or the areas within forests that are not influenced by other land cover types. These areas are of significant importance to native flora and fauna, since they generally are not subject to invasion by exotic species and are more resilient to the effects of climate change (Campbell et al., 2009). However, the expansion of development has reduced the amount of this core area, but the exact amount is still unknown. Current methods of estimating core area are not particularly precise, since edge, or the area of the forest that is most influenced by other land cover types, is quite variable and situation dependent. Therefore, the purpose of this study is to devise a new method for identifying areas that could qualify as "edge" within the Harvard Forest, in Petersham MA, using new remote sensing techniques. We sampled along eight transects perpendicular to the edge of an abandoned golf course within the Harvard Forest property. Vegetation inventories as well as Photosynthetically Active Radiation (PAR) at different heights within the canopy were used to determine edge depth. These measurements were then compared with small-footprint waveform aerial LiDAR datasets and imagery to model edge depths within Harvard Forest.

  17. Absorber topography dependence of phase edge effects

    NASA Astrophysics Data System (ADS)

    Shanker, Aamod; Sczyrba, Martin; Connolly, Brid; Waller, Laura; Neureuther, Andy

    2015-10-01

    Mask topography contributes to phase at the wafer plane, even for OMOG binary masks currently in use at the 22nm node in deep UV (193nm) lithography. Here, numerical experiments with rigorous FDTD simulation are used to study the impact of mask 3D effects on aerial imaging, by varying the height of the absorber stack and its sidewall angle. Using a thin mask boundary layer model to fit to rigorous simulations it is seen that increasing the absorber thickness, and hence the phase through the middle of a feature (bulk phase) monotonically changes the wafer-plane phase. Absorber height also influences best focus, revealed by an up/down shift in the Bossung plot (linewidth vs. defocus). Bossung plot tilt, however, responsible for process window variability at the wafer, is insensitive to changes in the absorber height (and hence also the bulk phase). It is seen to depend instead on EM edge diffraction from the thick mask edge (edge phase), but stays constant for variations in mask thickness within a 10% range. Both bulk phase and edge phase are also independent of sidewall angle fluctuation, which is seen to linearly affect the CD at the wafer, but does not alter wafer phase or the defocus process window. Notably, as mask topography varies, the effect of edge phase can be replicated by a thin mask model with 8nm wide boundary layers, irrespective of absorber height or sidewall angle. The conclusions are validated with measurements on phase shifting masks having different topographic parameters, confirming the strong dependence of phase variations at the wafer on bulk phase of the mask absorber.

  18. Alaska's Secondary Science Teachers and Students Receive Earth Systems Science Knowledge, GIS Know How and University Technical Support for Pre- College Research Experiences: The EDGE Project

    NASA Astrophysics Data System (ADS)

    Connor, C. L.; Prakash, A.

    2007-12-01

    Alaska's secondary school teachers are increasingly required to provide Earth systems science (ESS) education that integrates student observations of local natural processes related to rapid climate change with geospatial datasets and satellite imagery using Geographic Information Systems (GIS) technology. Such skills are also valued in various employment sectors of the state where job opportunities requiring Earth science and GIS training are increasing. University of Alaska's EDGE (Experiential Discoveries in Geoscience Education) program has provided training and classroom resources for 3 cohorts of inservice Alaska science and math teachers in GIS and Earth Systems Science (2005-2007). Summer workshops include geologic field experiences, GIS instruction, computer equipment and technical support for groups of Alaska high school (HS) and middle school (MS) science teachers each June and their students in August. Since 2005, EDGE has increased Alaska science and math teachers' Earth science content knowledge and developed their GIS and computer skills. In addition, EDGE has guided teachers using a follow-up, fall online course that provided more extensive ESS knowledge linked with classroom standards and provided course content that was directly transferable into their MS and HS science classrooms. EDGE teachers were mentored by University faculty and technical staff as they guided their own students through semester-scale, science fair style projects using geospatial data that was student- collected. EDGE program assessment indicates that all teachers have improved their ESS knowledge, GIS knowledge, and the use of technology in their classrooms. More than 230 middle school students have learned GIS, from EDGE teachers and 50 EDGE secondary students have conducted original research related to landscape change and its impacts on their own communities. Longer-term EDGE goals include improving student performance on the newly implemented (spring 2008) 10th grade

  19. Geometry-Based Edge Clustering for Graph Visualization

    SciTech Connect

    Cui, Wei W.; Zhou, Hong; Qu, Huamin; Wong, Pak C.; Li, X. M.

    2008-10-19

    Graphs have been widely used to model relationships among data. For large graphs, excessive edge crossings will make the display visually cluttered and thus difficult to explore. In this paper, we propose a novel geometry-based edge-clustering framework which can group edges into bundles to reduce the overall edge crossings. Our method uses a control mesh to guide the edge-clustering process; edge bundles can be formed by forcing all edges to pass through some control points on the mesh. The control mesh can be generated at different levels of detail either manually or automatically based on underlying graph patterns. Users can further interact with the edge-clustering results through several advanced visualization techniques such as color and opacity enhancement. Compared with other edge-clustering methods, our approach is intuitive, flexible, and efficient. The experiments on some large graphs demonstrate the effectiveness of our method.

  20. An ellipse detection algorithm based on edge classification

    NASA Astrophysics Data System (ADS)

    Yu, Liu; Chen, Feng; Huang, Jianming; Wei, Xiangquan

    2015-12-01

    In order to enhance the speed and accuracy of ellipse detection, an ellipse detection algorithm based on edge classification is proposed. Too many edge points are removed by making edge into point in serialized form and the distance constraint between the edge points. It achieves effective classification by the criteria of the angle between the edge points. And it makes the probability of randomly selecting the edge points falling on the same ellipse greatly increased. Ellipse fitting accuracy is significantly improved by the optimization of the RED algorithm. It uses Euclidean distance to measure the distance from the edge point to the elliptical boundary. Experimental results show that: it can detect ellipse well in case of edge with interference or edges blocking each other. It has higher detecting precision and less time consuming than the RED algorithm.

  1. Edge detection of color images using the HSL color space

    NASA Astrophysics Data System (ADS)

    Weeks, Arthur R.; Felix, Carlos E.; Myler, Harley R.

    1995-03-01

    Various edge detectors have been proposed as well as several different types of adaptive edge detectors, but the performance of many of these edge detectors depends on the features and the noise present in the grayscale image. Attempts have been made to extend edge detection to color images by applying grayscale edge detection methods to each of the individual red, blue, and green color components as well as to the hue, saturation, and intensity color components of the color image. The modulus 2(pi) nature of the hue color component makes its detection difficult. For example, a hue of 0 and 2(pi) yields the same color tint. Normal edge detection of a color image containing adjacent pixels with hue of 0 and 2(pi) could yield the presence of an edge when an edge is really not present. This paper presents a method of mapping the 2(pi) modulus hue space to a linear space enabling the edge detection of the hue color component using the Sobel edge detector. The results of this algorithm are compared against the edge detection methods using the red, blue, and green color components. By combining the hue edge image with the intensity and saturation edge images, more edge information is observed.

  2. Mortality after percutaneous edge-to-edge mitral valve repair: a contemporary review

    PubMed Central

    de Beenhouwer, Thomas; Swaans, Martin J.; Post, Marco C.; van der Heyden, Jan A. S.; Eefting, Frank D.; Rensing, Benno J. W. M.

    2016-01-01

    Percutaneous edge-to-edge mitral valve (MV) repair is a relatively new treatment option for mitral regurgitation (MR). After the feasibility and safety having been proved in low-surgical-risk patients, the use of this procedure has shifted more to the treatment of high-risk patients. With the absence of randomized controlled trials (RCT) for this particular subgroup, observational studies try to add evidence to the safety aspect of this procedure. These also provide short- and mid-term mortality figures. Several mortality predictors have been identified, which may help the optimal selection of patients who will benefit most from this technique. In this article we provide an overview of the literature about mortality and its predictors in patients treated with the percutaneous edge-to-edge device. PMID:27054105

  3. Tunneling Spectroscopy of the Edge in Quantum Hall Systems in Cleaved-Edge Overgrowth Devices

    NASA Astrophysics Data System (ADS)

    Oh, J. H.; Hilke, M.; Tsui, D. C.; Pfeiffer, L. N.; West, K. W.

    2004-03-01

    We present experimental results on the tunneling into the edge of a two dimensional electron gas (2DEG) obtained with a GaAs/AlGaAs cleaved edge overgrown structure in a strong perpendicular magnetic field. While the 2DEG shows typical fractional quantum Hall features of a very high mobility system, the tunneling into the edge exhibits a cross-over from a many-particle behavior (Luttinger liquid) at low tunneling voltages to a single particle characteristic at high voltages, which reflects absence of a many-body state away from the Fermi level. At high enough voltages, the single particle characteristic induces an asymmetry when tunneling into the 2DEG compared to tunneling out of it, which can be understood in the context of the single particle Landau level spectral distribution at the edge.

  4. Flow distortion at a dense forest edge

    NASA Astrophysics Data System (ADS)

    Dellwik, E.; Mann, J.

    2012-12-01

    Results from a forest edge experiment with two masts and one horizontally pointed wind lidar are presented. The experiment was performed at a dense beech forest edge of the Tromnæs forest, which is a 24m tall mature beech forest on the island Falster, Denmark. The topography at the site is flat. The masts were placed approximately 1.5 canopy heights upwind and downwind of the edge and are two canopy heights tall. We present data showing how the forest edge distorts the flow when the flow is perpendicular to the edge and towards the forest during near-neutral atmospheric stratification. Despite that the wind gradient above the canopy is similar before and after the edge, the momentum flux is strongly reduced above the canopy. This result is especially pronounced during summer and high leaf area index, when the momentum flux was slightly positive 1.2 canopy heights above ground level. This is contrary to the results by standard Reynolds' averaged Navier Stokes models that predict an overshoot of the momentum flux. Further above the forest, the total amount of turbulent kinetic energy remained constant compared to the upwind measurements. A reduction of the vertical variance of the flow was largely compensated by an increase in the lateral variance, whereas the streamwise variance remained approximately constant. This result is in contrast to the predictions by homogeneous rapid distortion theory. We apply and develop an alternative framework based on inhomogeneous rapid distortion theory in combination with the turbulence model by Mann (1994), which can predict the observed changes of the flow. The inhomogeneous rapid distortion theory takes the blocking of the flow by the top of the canopy into account. This effect turns out to suppress the vertical momentum flux drastically and redistribute the vertical fluctuations into the lateral direction. We show one- and two-point spectra for verification of the model. The results are relevant for understanding the on

  5. Crystallographic study of grain refinement in aluminum alloys using the edge-to-edge matching model

    SciTech Connect

    Zhang, M.-X. . E-mail: m.zhang@minmet.uq.edu.au; Kelly, P.M.; Easton, M.A.; Taylor, J.A.

    2005-03-01

    The edge-to-edge matching model for describing the interfacial crystallographic characteristics between two phases that are related by reproducible orientation relationships has been applied to the typical grain refiners in aluminum alloys. Excellent atomic matching between Al{sub 3}Ti nucleating substrates, known to be effective nucleation sites for primary Al, and the Al matrix in both close packed directions and close packed planes containing these directions have been identified. The crystallographic features of the grain refiner and the Al matrix are very consistent with the edge-to-edge matching model. For three other typical grain refiners for Al alloys, TiC (when a = 0.4328 nm), TiB{sub 2} and AlB{sub 2}, the matching only occurs between the close packed directions in both phases and between the second close packed plane of the Al matrix and the second close packed plane of the refiners. According to the model, it is predicted that Al{sub 3}Ti is a more powerful nucleating substrate for Al alloy than TiC, TiB{sub 2} and AlB{sub 2}. This agrees with the previous experimental results. The present work shows that the edge-to-edge matching model has the potential to be a powerful tool in discovering new and more powerful grain refiners for Al alloys.

  6. Carrier Drift Velocity and Edge Magnetoplasmons in Graphene

    NASA Astrophysics Data System (ADS)

    Petković, I.; Williams, F. I. B.; Bennaceur, K.; Portier, F.; Roche, P.; Glattli, D. C.

    2013-01-01

    We investigate electron dynamics at the graphene edge by studying the propagation of collective edge magnetoplasmon excitations. By timing the travel of narrow wave packets on picosecond time scales around exfoliated samples, we find chiral propagation with low attenuation at a velocity that is quantized on Hall plateaus. We extract the carrier drift contribution from the edge magnetoplasmon propagation and find it to be slightly less than the Fermi velocity, as expected for an abrupt edge. We also extract the characteristic length for Coulomb interaction at the edge and find it to be smaller than that for soft depletion-edge systems.

  7. Defects' geometric feature recognition based on infrared image edge detection

    NASA Astrophysics Data System (ADS)

    Junyan, Liu; Qingju, Tang; Yang, Wang; Yumei, Lu; Zhiping, Zhang

    2014-11-01

    Edge detection is an important technology in image segmentation, feature extraction and other digital image processing areas. Boundary contains a wealth of information in the image, so to extract defects' edges in infrared images effectively enables the identification of defects' geometric features. This paper analyzed the detection effect of classic edge detection operators, and proposed fuzzy C-means (FCM) clustering-Canny operator algorithm to achieve defects' edges in the infrared images. Results show that the proposed algorithm has better effect than the classic edge detection operators, which can identify the defects' geometric feature much more completely and clearly. The defects' diameters have been calculated based on the image edge detection results.

  8. The red edge of plant leaf reflectance

    NASA Technical Reports Server (NTRS)

    Horler, D. N. H.; Dockray, M.; Barber, J.

    1983-01-01

    A detailed study of the red edge spectral feature of green vegetation based on laboratory reflectance spectrophotometry is presented. A parameter lambda is defined as the wavelength is defined as the wavelength of maximum slope and found to be dependent on chlorophyll concentration. Species, development stage, leaf layering, and leaf water content of vegetation also influences lambda. The maximum slope parameter is found to be independent of simulated ground area coverage. The results are interpreted in terms of Beer's Law and Kubelka-Munk theory. The chlorophyll concentration dependence of lambda seems to be explained in terms of a pure absorption effect, and it is suggested that the existence of two lambda components arises from leaf scattering properties. The results indicate that red edge measurements will be valuable for assessment of vegetative chlorophyll status and leaf area index independently of ground cover variations, and will be particularly suitable for early stress detection.

  9. The cutting edge: Sharp biological materials

    NASA Astrophysics Data System (ADS)

    Meyers, M. A.; Lin, A. Y. M.; Lin, Y. S.; Olevsky, E. A.; Georgalis, S.

    2008-03-01

    Through hundreds of millions of years of evolution, organisms have developed a myriad of ingenious solutions to ensure and optimize survival and success. Biological materials that comprise organisms are synthesized at ambient temperature and pressure and mostly in aqueous environments. This process, mediated by proteins, limits the range of materials at the disposal of nature and therefore the design plays a pivotal role. This article focuses on sharp edges and serrations as important survival and predating mechanisms in a number of plants, insects, fishes, and mammals. Some plants have sharp edges covered with serrations. The proboscis of mosquitoes and stinger of bees are examples in insects. Serrations are a prominent feature in many fish teeth, and rodents have teeth that are sharpened continuously, ensuring their sharpness and efficacy. Some current bioinspired applications will also be reviewed.

  10. Edges of Saturn's rings are fractal.

    PubMed

    Li, Jun; Ostoja-Starzewski, Martin

    2015-01-01

    The images recently sent by the Cassini spacecraft mission (on the NASA website http://saturn.jpl.nasa.gov/photos/halloffame/) show the complex and beautiful rings of Saturn. Over the past few decades, various conjectures were advanced that Saturn's rings are Cantor-like sets, although no convincing fractal analysis of actual images has ever appeared. Here we focus on four images sent by the Cassini spacecraft mission (slide #42 "Mapping Clumps in Saturn's Rings", slide #54 "Scattered Sunshine", slide #66 taken two weeks before the planet's Augus't 200'9 equinox, and slide #68 showing edge waves raised by Daphnis on the Keeler Gap) and one image from the Voyager 2' mission in 1981. Using three box-counting methods, we determine the fractal dimension of edges of rings seen here to be consistently about 1.63 ~ 1.78. This clarifies in what sense Saturn's rings are fractal. PMID:25883885

  11. GSGG edge cladding development: Final technical report

    SciTech Connect

    Izumitani, T.; Meissner, H.E.; Toratani, H.

    1986-11-15

    The objectives of this project have been: (1) Investigate the possibility of chemical etching of GSGG crystal slabs to obtain increased strength. (2) Design and construct a simplified mold assembly for casting cladding glass to the edges of crystal slabs of different dimensions. (3) Conduct casting experiments to evaluate the redesigned mold assembly and to determine stresses as function of thermal expansion coefficient of cladding glass. (4) Clad larger sizes of GGG slabs as they become available. These tasks have been achieved. Chemical etching of GSGG slabs does not appear possible with any other acid than H/sub 3/PO/sub 4/ at temperatures above 300/sup 0/C. A mold assembly has been constructed which allowed casting cladding glass around the edges of the largest GGG slabs available (10 x 20 x 160 mm) without causing breakage through the annealing step.

  12. Kinetic Equations for the Plasma Edge

    NASA Astrophysics Data System (ADS)

    Abel, Ian; Hammett, Greg

    2015-11-01

    A hybrid fluid-kinetic framework for studying large-amplitude fluctuations in the edge of tokamak plasmas is presented. We derive equations for the behavior of an anisotropic plasma in the presence of both large fluctuations and steep gradients. The system consists of kinetic equations for electrons and ions, supplemented with fluid equations for the electromagnetic fields. In this way it builds upon both kinetic MHD and from the use of vorticity equations in gyrokinetics. This framework, by including both Alfvénic (including current-driven modes) and drift wave dynamics, can handle fully nonlinear perturbations such as erupting ELM filaments and blob-based turbulence. We not only present equations for such fast behavior, but also develop higher order equations that describe pedestal equilibria and slow scrape-off-layer dynamics. The relationship between this framework and existing collisional edge models is made clear.

  13. Edges of Saturn's rings are fractal.

    PubMed

    Li, Jun; Ostoja-Starzewski, Martin

    2015-01-01

    The images recently sent by the Cassini spacecraft mission (on the NASA website http://saturn.jpl.nasa.gov/photos/halloffame/) show the complex and beautiful rings of Saturn. Over the past few decades, various conjectures were advanced that Saturn's rings are Cantor-like sets, although no convincing fractal analysis of actual images has ever appeared. Here we focus on four images sent by the Cassini spacecraft mission (slide #42 "Mapping Clumps in Saturn's Rings", slide #54 "Scattered Sunshine", slide #66 taken two weeks before the planet's Augus't 200'9 equinox, and slide #68 showing edge waves raised by Daphnis on the Keeler Gap) and one image from the Voyager 2' mission in 1981. Using three box-counting methods, we determine the fractal dimension of edges of rings seen here to be consistently about 1.63 ~ 1.78. This clarifies in what sense Saturn's rings are fractal.

  14. Quantum nature of edge magnetism in graphene.

    PubMed

    Golor, Michael; Wessel, Stefan; Schmidt, Manuel J

    2014-01-31

    It is argued that the subtle crossover from decoherence-dominated classical magnetism to fluctuation-dominated quantum magnetism is experimentally accessible in graphene nanoribbons. We show that the width of a nanoribbon determines whether the edge magnetism is on the classical side, on the quantum side, or in between. In the classical regime, decoherence is dominant and leads to static spin polarizations at the ribbon edges, which are well described by mean-field theories. The quantum Zeno effect is identified as the basic mechanism which is responsible for the spin polarization and thereby enables the application of graphene in spintronics. On the quantum side, however, the spin polarization is destroyed by dynamical processes. The great tunability of graphene magnetism thus offers a viable route for the study of the quantum-classical crossover.

  15. Permanent magnet edge-field quadrupole

    DOEpatents

    Tatchyn, R.O.

    1997-01-21

    Planar permanent magnet edge-field quadrupoles for use in particle accelerating machines and in insertion devices designed to generate spontaneous or coherent radiation from moving charged particles are disclosed. The invention comprises four magnetized rectangular pieces of permanent magnet material with substantially similar dimensions arranged into two planar arrays situated to generate a field with a substantially dominant quadrupole component in regions close to the device axis. 10 figs.

  16. Edge rotational magnons in magnonic crystals

    SciTech Connect

    Lisenkov, Ivan Kalyabin, Dmitry; Nikitov, Sergey

    2013-11-11

    It is predicted that in 2D magnonic crystals the edge rotational magnons of forward volume magnetostatic spin waves can exist. Under certain conditions, locally bounded magnons may appear within the crystal consisting of the ferromagnetic matrix and periodically inserted magnetic/non-magnetic inclusions. It is also shown that interplay of different resonances in 2D magnonic crystal may provide conditions for spin wave modes existence with negative group velocity.

  17. Rimmed and edge thickened Stodola shaped flywheel

    DOEpatents

    Kulkarni, S.V.; Stone, R.G.

    1983-10-11

    A flywheel is described that is useful for energy storage in a hybrid vehicle automotive power system or in some stationary applications. The flywheel has a body composed of essentially planar isotropic high strength material. The flywheel body is enclosed by a rim of circumferentially wound fiber embedded in resin. The rim promotes flywheel safety and survivability. The flywheel has a truncated and edge thickened Stodola shape designed to optimize system mass and energy storage capability. 6 figs.

  18. Images of Edge Turbulence in NSTX

    SciTech Connect

    S.J. Zweben; C.E. Bush; R. Maqueda; T. Munsat; D. Stotler; J. Lowrance; V. Mastracola; G. Renda

    2004-07-16

    The 2-D structure of edge plasma turbulence has been measured in the National Spherical Torus Experiment (NSTX) by viewing the emission of the Da spectral line of deuterium. Images have been made at framing rates of up to 250,000 frames/sec using an ultra-high speed CCD camera developed by Princeton Scientific Instruments. A sequence of images showing the transition between L-mode and H-mode states is shown.

  19. Permanent magnet edge-field quadrupole

    DOEpatents

    Tatchyn, Roman O.

    1997-01-01

    Planar permanent magnet edge-field quadrupoles for use in particle accelerating machines and in insertion devices designed to generate spontaneous or coherent radiation from moving charged particles are disclosed. The invention comprises four magnetized rectangular pieces of permanent magnet material with substantially similar dimensions arranged into two planar arrays situated to generate a field with a substantially dominant quadrupole component in regions close to the device axis.

  20. Mating system shifts on the trailing edge

    PubMed Central

    Levin, Donald A.

    2012-01-01

    Background The trailing edges of species ranges are becoming a subject of increasing interest as the environment changes due to global warming. Trailing edge populations are likely to face extinction because of a decline in numbers and an inability to evolve new adaptations with sufficient speed. Discussions of character change in the trailing edge have focused on physiological, exomorphic and phenological traits. The mating pattern within populations has not been part of the discourse, in spite of the fact that the mating pattern may affect the ability of populations to respond to environmental change and to maintain their sizes. In this paper, the case is made that a substantial increase in self-fertilization rates may occur via plastic responses to stress. Scope and Conclusions Small populations on the trailing edge are especially vulnerable to environmental change because of inadequate levels of cross-fertilization. Evidence is presented that a deficiency of cross-seed production is due to inadequate pollinator services and a paucity of self-incompatibility alleles within populations. Evidence also is presented that if plants are self-compatible, self-fertilization may compensate in part for this deficiency through a stress-induced increase in levels of self-compatibility and stress-induced alterations in floral morphology that elevate self-pollination. Whereas increased self-fertility may afford populations the time to adapt to their changing environments, it can be concluded that increased selfing is not a panacea for the ills of environmental change, because it will lead to substantial reductions in genetic diversity, which may render adaptation unlikely. PMID:21980190

  1. Differentiator design and performance for edge sharpening

    USGS Publications Warehouse

    Pan, Jeng-Jong; Domingue, Julia O.

    1990-01-01

    A two-dimensional differentiator is useful for edge sharpening in digital image processing. In the design of a differentiator, differentiator coefficients that satisfy the specification of frequency response must be approximated. Four mathematical techniques - the minimax method, least-squares method, nonlinear programming, and linear programming - can be applied to solve the approximation problem. Results indicated that the differentiator derived from linear programming gives the highest resolution. -from Authors

  2. Search for absorption edges in superexpansion bursts

    NASA Astrophysics Data System (ADS)

    in't Zand, Jean

    2013-09-01

    Our goal is to measure with the LETGS a series of bright type-I X-ray bursts with strong photospheric radius expansion ('superexpansion') to search for absorption edges due to the ashes of nuclear burning. We request a quick TOO, to be triggered by ISS-MAXI and Swift-BAT, with a total exposure time of 100 ks to obtain the detection of about 10 bursts.

  3. Robotic Vision With Enhanced Detection Of Edges

    NASA Technical Reports Server (NTRS)

    Davis, V. L.; Shawaga, L.; Walsh, P.; Kambies, K.

    1993-01-01

    Robotic vision subsystem provides enhanced detection of edges as it preprocesses image of target moving in six degrees of freedom. Subsystem designed to filter out high (spatial) frequency components in image, with frequency response tuned to size of object detected. Blurring and background noise reduced to avoid false detection of moving target. Image produced used by another vision subsystem guiding robot to mate with target. Produces less noise and operates more reliably.

  4. Edge direction and the structure of networks.

    PubMed

    Foster, Jacob G; Foster, David V; Grassberger, Peter; Paczuski, Maya

    2010-06-15

    Directed networks are ubiquitous and are necessary to represent complex systems with asymmetric interactions--from food webs to the World Wide Web. Despite the importance of edge direction for detecting local and community structure, it has been disregarded in studying a basic type of global diversity in networks: the tendency of nodes with similar numbers of edges to connect. This tendency, called assortativity, affects crucial structural and dynamic properties of real-world networks, such as error tolerance or epidemic spreading. Here we demonstrate that edge direction has profound effects on assortativity. We define a set of four directed assortativity measures and assign statistical significance by comparison to randomized networks. We apply these measures to three network classes--online/social networks, food webs, and word-adjacency networks. Our measures (i) reveal patterns common to each class, (ii) separate networks that have been previously classified together, and (iii) expose limitations of several existing theoretical models. We reject the standard classification of directed networks as purely assortative or disassortative. Many display a class-specific mixture, likely reflecting functional or historical constraints, contingencies, and forces guiding the system's evolution. PMID:20505119

  5. Large eddy simulation of trailing edge noise

    NASA Astrophysics Data System (ADS)

    Keller, Jacob; Nitzkorski, Zane; Mahesh, Krishnan

    2015-11-01

    Noise generation is an important engineering constraint to many marine vehicles. A significant portion of the noise comes from propellers and rotors, specifically due to flow interactions at the trailing edge. Large eddy simulation is used to investigate the noise produced by a turbulent 45 degree beveled trailing edge and a NACA 0012 airfoil. A porous surface Ffowcs-Williams and Hawkings acoustic analogy is combined with a dynamic endcapping method to compute the sound. This methodology allows for the impact of incident flow noise versus the total noise to be assessed. LES results for the 45 degree beveled trailing edge are compared to experiment at M = 0 . 1 and Rec = 1 . 9 e 6 . The effect of boundary layer thickness on sound production is investigated by computing using both the experimental boundary layer thickness and a thinner boundary layer. Direct numerical simulation results of the NACA 0012 are compared to available data at M = 0 . 4 and Rec = 5 . 0 e 4 for both the hydrodynamic field and the acoustic field. Sound intensities and directivities are investigated and compared. Finally, some of the physical mechanisms of far-field noise generation, common to the two configurations, are discussed. Supported by Office of Naval research.

  6. Cavitation on Hydrofoils with Leading Edge Protuberances

    NASA Astrophysics Data System (ADS)

    Custodio, Derrick; Henoch, Charles; Johari, Hamid; Office of Naval Research Collaboration

    2012-11-01

    The effects of spanwise-uniform sinusoidal leading edge protuberances on the flow characteristics and forces of finite-span hydrofoils under vaporous cavitation conditions were examined experimentally over angles of attack ranging from -9° α <= 27°. Two planforms were studied, rectangular and swept, at a Reynolds number of ~ 720,000. Two protuberance wavelengths, λ = 0.25 c and 0.50 c, and three amplitudes, A = 0.025 c, 0.05 c, and 0.12 c, were examined as they resemble the humpback whale flipper morphology. All hydrofoils retain a mean NACA 634-021 profile. The forces and moments were measured at a freestream velocity of 7.2 m/s, and high-speed digital photography was used to capture flow field images at several angles of attack. The cavitation number corresponding to incipient leading edge cavitation was also calculated. As far as forces and cavitation number are concerned, results show that the baseline hydrofoil tends to have nearly equal or improved performance over the modified hydrofoils at most angles of attack tested. Flow images reveal that it is possible that the extent of sheet and tip vortex cavitation can be reduced with the introduction of leading edge protuberances. The forces and cavitation characteristics will be presented. Sponsored by the ONR-ULI program.

  7. Edge ratio and community structure in networks

    NASA Astrophysics Data System (ADS)

    Cafieri, Sonia; Hansen, Pierre; Liberti, Leo

    2010-02-01

    A hierarchical divisive algorithm is proposed for identifying communities in complex networks. To that effect, the definition of community in the weak sense of Radicchi [Proc. Natl. Acad. Sci. U.S.A. 101, 2658 (2004)] is extended into a criterion for a bipartition to be optimal: one seeks to maximize the minimum for both classes of the bipartition of the ratio of inner edges to cut edges. A mathematical program is used within a dichotomous search to do this in an optimal way for each bipartition. This includes an exact solution of the problem of detecting indivisible communities. The resulting hierarchical divisive algorithm is compared with exact modularity maximization on both artificial and real world data sets. For two problems of the former kind optimal solutions are found; for five problems of the latter kind the edge ratio algorithm always appears to be competitive. Moreover, it provides additional information in several cases, notably through the use of the dendrogram summarizing the resolution. Finally, both algorithms are compared on reduced versions of the data sets of Girvan and Newman [Proc. Natl. Acad. Sci. U.S.A. 99, 7821 (2002)] and of Lancichinetti [Phys. Rev. E 78, 046110 (2008)]. Results for these instances appear to be comparable.

  8. Plasma edge studies using carbon resistance probes

    SciTech Connect

    Wampler, W.R.; Manos, D.M.

    1983-04-01

    A new experimental technique, the resistance probe, was used to study the plasma edge in the PLT and PDX tokamaks. This technique involves measuring the change in resistance of a thin carbon film due to bombardment by energetic particles escaping the plasma. The probes have been calibrated by measuring the resistance change caused by implantation of various ions at different energies. A model has been developed which can be used to determine the flux and energy of the incident particles from the measured resistance changes. For probes exposed in PDX and PLT near the wall, resistance changes were observed due to charge exchange neutrals. Larger changes were observed in the ion scrape-off region closer to the plasma. In PLT the effect of ions at the plasma edge begins to dominate the neutral flux near the radius of the ring limiter. The energy of ions at the plasma edge was estimated to be low (< or approx. =100 eV) in PDX during neutral beam-heated discharges, but higher (> or approx. =300 eV) in PLT during ion cyclotron resonance heating.

  9. The edge plasma and divertor in TIBER

    SciTech Connect

    Barr, W.L.

    1987-10-16

    An open divertor configuration has been adopted for TIBER. Most recent designs, including DIII-D, NET and CIT use open configurations and rely on a dense edge plasma to shield the plasma from the gas produced at the neutralizer plate. Experiments on ASDEX, PDX, D-III, and recently on DIII-D have shown that a dense edge plasma can be produced by re-ionizing most of the gas produced at the plate. This high recycling mode allows a large flux of particles to carry the heat to the plate, so that the mean energy per particle can be low. Erosion of the plate can be greatly reduced if the average impact energy of the ions at the plate can be reduced to near or below the threshold for sputtering of the plate material. The present configuration allows part of the flux of edge plasma ions to be neutralized at the entrance to the pumping duct so that helium is pumped as well as hydrogen. 7 refs., 3 figs.

  10. Issues in Kinetic Edge Turbulence Simulation

    NASA Astrophysics Data System (ADS)

    Parker, S. E.; Chen, Y.; Lang, J.

    2006-10-01

    Simulations of trapped electron modes are underway using GEM [1,2], a global electromagnetic gyrokinetic delta-f simulation with collisions. We report results with no temperature gradient so that ITG and ETG instabilities are not present. For typical weak density gradient core values, the CTEM is dominant. However, for steeper density gradient edge values, higher k drift-waves are most unstable [J. Lang this mtg.]. For the weaker density gradient core case, nonlinear simulations using GEM are routine. For the steeper gradient edge case, the nonlinear fluctuations are very high and a stationary state has not been obtained. More physics, e.g. profile variation and equilibrium ExB shear flow should be significantly stabilizing, and may make such simulations feasible using standard delta-f techniques. These features are fully implemented in GEM and research is ongoing. One approach to addressing the high fluctuation levels in the edge turbulence regime is the particle-continuum method [3]. A new scheme that periodically resets the particle weights, using a Maxwellian particle load is being tested in GEM [Y. Chen this mtg.] and will be discussed. [1] Y. Chen, S. Parker, J. Comput. Phys. 189 463 (2003). [2] Y. Chen, S. Parker, accepted, available on-line, J. Comput. Phys. (2006). [4] S. Vadlamani, S. Parker, Y. Chen and C. Kim, Comput. Phys. Comm. 164 209 (2004).

  11. Edge direction and the structure of networks.

    PubMed

    Foster, Jacob G; Foster, David V; Grassberger, Peter; Paczuski, Maya

    2010-06-15

    Directed networks are ubiquitous and are necessary to represent complex systems with asymmetric interactions--from food webs to the World Wide Web. Despite the importance of edge direction for detecting local and community structure, it has been disregarded in studying a basic type of global diversity in networks: the tendency of nodes with similar numbers of edges to connect. This tendency, called assortativity, affects crucial structural and dynamic properties of real-world networks, such as error tolerance or epidemic spreading. Here we demonstrate that edge direction has profound effects on assortativity. We define a set of four directed assortativity measures and assign statistical significance by comparison to randomized networks. We apply these measures to three network classes--online/social networks, food webs, and word-adjacency networks. Our measures (i) reveal patterns common to each class, (ii) separate networks that have been previously classified together, and (iii) expose limitations of several existing theoretical models. We reject the standard classification of directed networks as purely assortative or disassortative. Many display a class-specific mixture, likely reflecting functional or historical constraints, contingencies, and forces guiding the system's evolution.

  12. Emergent Properties of Patch Shapes Affect Edge Permeability to Animals

    PubMed Central

    Nams, Vilis O.

    2011-01-01

    Animal travel between habitat patches affects populations, communities and ecosystems. There are three levels of organization of edge properties, and each of these can affect animals. At the lowest level are the different habitats on each side of an edge, then there is the edge itself, and finally, at the highest level of organization, is the geometry or structure of the edge. This study used computer simulations to (1) find out whether effects of edge shapes on animal behavior can arise as emergent properties solely due to reactions to edges in general, without the animals reacting to the shapes of the edges, and to (2) generate predictions to allow field and experimental studies to test mechanisms of edge shape response. Individual animals were modeled traveling inside a habitat patch that had different kinds of edge shapes (convex, concave and straight). When animals responded edges of patches, this created an emergent property of responding to the shape of the edge. The response was mostly to absolute width of the shapes, and not the narrowness of them. When animals were attracted to edges, then they tended to collect in convexities and disperse from concavities, and the opposite happened when animals avoided edges. Most of the responses occurred within a distance of 40% of the perceptual range from the tip of the shapes. Predictions were produced for directionality at various locations and combinations of treatments, to be used for testing edge behavior mechanisms. These results suggest that edge shapes tend to either concentrate or disperse animals, simply because the animals are either attracted to or avoid edges, with an effect as great as 3 times the normal density. Thus edge shape could affect processes like pollination, seed predation and dispersal and predator abundance. PMID:21747965

  13. Observation of unconventional edge states in ‘photonic graphene’

    NASA Astrophysics Data System (ADS)

    Plotnik, Yonatan; Rechtsman, Mikael C.; Song, Daohong; Heinrich, Matthias; Zeuner, Julia M.; Nolte, Stefan; Lumer, Yaakov; Malkova, Natalia; Xu, Jingjun; Szameit, Alexander; Chen, Zhigang; Segev, Mordechai

    2014-01-01

    Graphene, a two-dimensional honeycomb lattice of carbon atoms, has been attracting much interest in recent years. Electrons therein behave as massless relativistic particles, giving rise to strikingly unconventional phenomena. Graphene edge states are essential for understanding the electronic properties of this material. However, the coarse or impure nature of the graphene edges hampers the ability to directly probe the edge states. Perhaps the best example is given by the edge states on the bearded edge that have never been observed—because such an edge is unstable in graphene. Here, we use the optical equivalent of graphene—a photonic honeycomb lattice—to study the edge states and their properties. We directly image the edge states on both the zigzag and bearded edges of this photonic graphene, measure their dispersion properties, and most importantly, find a new type of edge state: one residing on the bearded edge that has never been predicted or observed. This edge state lies near the Van Hove singularity in the edge band structure and can be classified as a Tamm-like state lacking any surface defect. The mechanism underlying its formation may counterintuitively appear in other crystalline systems.

  14. Urbanization Impacts on Mammals across Urban-Forest Edges and a Predictive Model of Edge Effects

    PubMed Central

    Villaseñor, Nélida R.; Driscoll, Don A.; Escobar, Martín A. H.; Gibbons, Philip; Lindenmayer, David B.

    2014-01-01

    With accelerating rates of urbanization worldwide, a better understanding of ecological processes at the wildland-urban interface is critical to conserve biodiversity. We explored the effects of high and low-density housing developments on forest-dwelling mammals. Based on habitat characteristics, we expected a gradual decline in species abundance across forest-urban edges and an increased decline rate in higher contrast edges. We surveyed arboreal mammals in sites of high and low housing density along 600 m transects that spanned urban areas and areas turn on adjacent native forest. We also surveyed forest controls to test whether edge effects extended beyond our edge transects. We fitted models describing richness, total abundance and individual species abundance. Low-density housing developments provided suitable habitat for most arboreal mammals. In contrast, high-density housing developments had lower species richness, total abundance and individual species abundance, but supported the highest abundances of an urban adapter (Trichosurus vulpecula). We did not find the predicted gradual decline in species abundance. Of four species analysed, three exhibited no response to the proximity of urban boundaries, but spilled over into adjacent urban habitat to differing extents. One species (Petaurus australis) had an extended negative response to urban boundaries, suggesting that urban development has impacts beyond 300 m into adjacent forest. Our empirical work demonstrates that high-density housing developments have negative effects on both community and species level responses, except for one urban adapter. We developed a new predictive model of edge effects based on our results and the literature. To predict animal responses across edges, our framework integrates for first time: (1) habitat quality/preference, (2) species response with the proximity to the adjacent habitat, and (3) spillover extent/sensitivity to adjacent habitat boundaries. This framework will

  15. Urbanization impacts on mammals across urban-forest edges and a predictive model of edge effects.

    PubMed

    Villaseñor, Nélida R; Driscoll, Don A; Escobar, Martín A H; Gibbons, Philip; Lindenmayer, David B

    2014-01-01

    With accelerating rates of urbanization worldwide, a better understanding of ecological processes at the wildland-urban interface is critical to conserve biodiversity. We explored the effects of high and low-density housing developments on forest-dwelling mammals. Based on habitat characteristics, we expected a gradual decline in species abundance across forest-urban edges and an increased decline rate in higher contrast edges. We surveyed arboreal mammals in sites of high and low housing density along 600 m transects that spanned urban areas and areas turn on adjacent native forest. We also surveyed forest controls to test whether edge effects extended beyond our edge transects. We fitted models describing richness, total abundance and individual species abundance. Low-density housing developments provided suitable habitat for most arboreal mammals. In contrast, high-density housing developments had lower species richness, total abundance and individual species abundance, but supported the highest abundances of an urban adapter (Trichosurus vulpecula). We did not find the predicted gradual decline in species abundance. Of four species analysed, three exhibited no response to the proximity of urban boundaries, but spilled over into adjacent urban habitat to differing extents. One species (Petaurus australis) had an extended negative response to urban boundaries, suggesting that urban development has impacts beyond 300 m into adjacent forest. Our empirical work demonstrates that high-density housing developments have negative effects on both community and species level responses, except for one urban adapter. We developed a new predictive model of edge effects based on our results and the literature. To predict animal responses across edges, our framework integrates for first time: (1) habitat quality/preference, (2) species response with the proximity to the adjacent habitat, and (3) spillover extent/sensitivity to adjacent habitat boundaries. This framework will

  16. 3. EASTERN EDGE OF POST ENGINEER'S SHOPS AND YARD, LOOKING ...

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

    3. EASTERN EDGE OF POST ENGINEER'S SHOPS AND YARD, LOOKING 312 DEGREES NORTH WEST, EUCALYPTUS TREES DENOTE EDGE OF PRESIDIO. - Presidio of San Francisco, Post Engineer's Headquarters Office, Crissy Field North cantonment, San Francisco, San Francisco County, CA

  17. Method for encapsulating the edge of a flexible sheet

    SciTech Connect

    Keenihan, James R; Clarey, Todd M

    2013-02-19

    The present invention is premised upon an inventive method of producing an over-molded edge portion on a flexible substrate, wherein the edge portion is void of open areas due to support devices in the mold cavity.

  18. Edge State and Intrinsic Hole Doping in Bilayer Phosphorene

    NASA Astrophysics Data System (ADS)

    Osada, Toshihito

    2015-01-01

    Using a simple LCAO model by Harrison, we have qualitatively studied the edge state of bilayer phosphorene, which is a unit structure of the layered crystal of black phosphorus. This model successfully reproduces the isolated edge state in the bulk gap in monolayer phosphorene. In bilayer phosphorene, however, it shows that edge states are almost buried in the valence band and there is no isolated midgap edge state at the zigzag edge. Since the buried edge state works as acceptor, holes are doped from the edge state into the bulk. This gives a possible explanation for p-type conduction in undoped black phosphorus. Under the vertical electric field, the intrinsic hole doping is reduced because a part of edge states move into the gap. These features of bilayer phosphorene might be better suited for device application.

  19. Comparison of edges detected at different polarisations in MAESTRO data

    NASA Technical Reports Server (NTRS)

    Caves, Ronald G.; Harley, Peter J.; Quegan, Shaun

    1992-01-01

    Edge detection would appear to be a crucial tool for analyzing multi-polarized, multi-frequency, and multi-temporal Synthetic Aperture Radar (SAR) images. Edge structure provides a simple means for comparing different polarizations and frequencies, and for detecting changes over time. Due to the fact that edges and segments (homogeneous regions) are dual concepts, edge detection has an important role to play in identifying segments within which mean backscatter measurements for use in image classification can be made. As part of a general investigation into edge detection in SAR imagery, an initial investigation was carried out into the detectability and nature of edges in multi-polarized and multi-frequency SAR images. The contrast ratio (CR) operator was used to detect edges. This operator was previously shown to perform well at detecting edges in single-polarized and single-frequency SAR images.

  20. Life on the edge: characterising the edges of mutually non-dominating sets.

    PubMed

    Everson, Richard M; Walker, David J; Fieldsend, Jonathan E

    2014-01-01

    Multi-objective optimisation yields an estimated Pareto front of mutually non- dominating solutions, but with more than three objectives, understanding the relationships between solutions is challenging. Natural solutions to use as landmarks are those lying near to the edges of the mutually non-dominating set. We propose four definitions of edge points for many-objective mutually non-dominating sets and examine the relations between them. The first defines edge points to be those that extend the range of the attainment surface. This is shown to be equivalent to finding points which are not dominated on projection onto subsets of the objectives. If the objectives are to be minimised, a further definition considers points which are not dominated under maximisation when projected onto objective subsets. A final definition looks for edges via alternative projections of the set. We examine the relations between these definitions and their efficacy in many dimensions for synthetic concave- and convex-shaped sets, and on solutions to a prototypical many-objective optimisation problem, showing how they can reveal information about the structure of the estimated Pareto front. We show that the "controlling dominance area of solutions" modification of the dominance relation can be effectively used to locate edges and interior points of high-dimensional mutually non-dominating sets.

  1. Topological edge Mott insulating state in two dimensions at finite temperatures: Bulk and edge analysis

    NASA Astrophysics Data System (ADS)

    Yoshida, Tsuneya; Kawakami, Norio

    2016-08-01

    We study a bilayer Kane-Mele-Hubbard model with lattice distortion and interlayer spin exchange interaction under cylinder geometry. Our analysis based on real-space dynamical mean field theory with continuous-time quantum Monte Carlo demonstrates the emergence of a topological edge Mott insulating (TEMI) state which hosts gapless edge modes only in collective spin excitations. This is confirmed by the numerical calculations at finite temperatures for the spin-Hall conductivity and the single-particle excitation spectrum; the spin-Hall conductivity is almost quantized, σspinx y˜2 (e /2 π ) , predicting gapless edge modes carrying the spin current, while the helical edge modes in the single-particle spectrum are gapped out with respecting symmetry. It is clarified how the TEMI state evolves from the ordinary spin-Hall insulating state with increasing the Hubbard interaction at a given temperature and then undergoes a phase transition to a trivial Mott insulating state. With a bosonization approach at zero temperature, we further address which collective modes host gapless edge modes in the TEMI state.

  2. Improved method of edge coating flat ribbon wire

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Method to coat the edges of flat ribbon wire is devised by using enamel with modified flow properties due to addition of 2 to 4 percent silicon. Conventional coating procedes several edge coatings to minimize oxidation and additional conventional coats are applied after edge coating to build up thickness.

  3. Method of forming densified edge seals for fuel cell components

    DOEpatents

    DeCasperis, Anthony J.; Roethlein, Richard J.; Breault, Richard D.

    1981-01-01

    A porous fuel cell component, such as an electrode substrate, has a densified edge which forms an improved gas seal during operation when soaked with electrolyte. The edges are made from the same composition as the rest of the component and are made by compressing an increased thickness of this material along the edges during the fabrication process.

  4. 12 CFR 211.5 - Edge and agreement corporations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... given written notice of its intention to do so to its Reserve Bank, unless the Edge corporation is... and Q (12 CFR parts 204 and 217) in the same manner and to the same extent as if the Edge or agreement... (12 CFR part 204), and other Edge and agreement corporations; (3) Money-market instruments...

  5. Shashkov`s method retaining cell-edge unknowns

    SciTech Connect

    Roberts, R.M.

    1996-01-05

    Shashkov`s method for scalar cell-edge and cell-center variables is derived. Dot products for cell-edge vectors are computed for a corner of the cell. Next, the divergence and gradient are discretized. The diffusion equation is solved with cell-edge continuity and boundary conditions. A symmetric positive definite solution matrix is proven.

  6. 16 CFR 1211.12 - Requirements for edge sensors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Global Engineering Documents... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Requirements for edge sensors. 1211.12... Requirements for edge sensors. (a) Normal operation test. (1) When installed on a representative door edge,...

  7. Edge-based correlation image registration for multispectral imaging

    DOEpatents

    Nandy, Prabal

    2009-11-17

    Registration information for images of a common target obtained from a plurality of different spectral bands can be obtained by combining edge detection and phase correlation. The images are edge-filtered, and pairs of the edge-filtered images are then phase correlated to produce phase correlation images. The registration information can be determined based on these phase correlation images.

  8. Interference of topologically protected edge states in silicene nanoribbons

    NASA Astrophysics Data System (ADS)

    Ezawa, Motohiko; Nagaosa, Naoto

    2013-09-01

    Silicene is a graphene-like honeycomb structure made of silicon atoms. It is a two-dimensional quantum spin-Hall insulator due to the spin-orbit interaction. According to the bulk-edge correspondence we expect zero-energy edge channels to appear in silicene nanoribbons. The behaviors of the helical edge channels are completely different between the armchair and the zigzag edges. Zero-energy states disappear in armchair nanoribbons despite the bulk-edge correspondence, while they appear as zigzag nanoribbons even if the width is quite narrow. The difference originates in the penetration depth of the helical edge channel, which is antiproportional to the spin-orbit gap for the armchair edge, while it remains as short as the lattice constant for the zigzag edge. These properties make clear distinctions between silicene and graphene nanoribbons, especially for armchair edges: In silicene edge states emerge as required by its topology, though the zero-energy states disappear from the energy spectrum, whereas in graphene no edge states exist. The emergence of edge states in armchair nanoribbons must be experimentally detectable by scanning tunneling microscopy, and may well serve as an experimental signal that silicene is a topological insulator.

  9. 16 CFR 1211.12 - Requirements for edge sensors.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Global Engineering Documents... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Requirements for edge sensors. 1211.12... Requirements for edge sensors. (a) Normal operation test. (1) When installed on a representative door edge,...

  10. 16 CFR 1211.12 - Requirements for edge sensors.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Global Engineering Documents... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Requirements for edge sensors. 1211.12... Requirements for edge sensors. (a) Normal operation test. (1) When installed on a representative door edge,...

  11. 16 CFR 1211.12 - Requirements for edge sensors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Global Engineering Documents... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Requirements for edge sensors. 1211.12... Requirements for edge sensors. (a) Normal operation test. (1) When installed on a representative door edge,...

  12. 16 CFR 1211.12 - Requirements for edge sensors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Global Engineering Documents... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Requirements for edge sensors. 1211.12... Requirements for edge sensors. (a) Normal operation test. (1) When installed on a representative door edge,...

  13. Climate Data Homogenization Using Edge Detection Algorithms

    NASA Astrophysics Data System (ADS)

    Hammann, A. C.; Rennermalm, A. K.

    2015-12-01

    The problem of climate data homogenization has predominantly been addressed by testing the likelihood of one or more breaks inserted into a given time series and modeling the mean to be stationary in between the breaks. We recast the same problem in a slightly different form: that of detecting step-like changes in noisy data, and observe that this problem has spawned a large number of approaches to its solution as the "edge detection" problem in image processing. With respect to climate data, we ask the question: How can we optimally separate step-like from smoothly-varying low-frequency signals? We study the hypothesis that the edge-detection approach makes better use of all information contained in the time series than the "traditional" approach (e.g. Caussinus and Mestre, 2004), which we base on several observations. 1) The traditional formulation of the problem reduces the available information from the outset to that contained in the test statistic. 2) The criterion of local steepness of the low-frequency variability, while at least hypothetically useful, is ignored. 3) The practice of using monthly data corresponds, mathematically, to applying a moving average filter (to reduce noise) and subsequent subsampling of the result; this subsampling reduces the amount of available information beyond what is necessary for noise reduction. Most importantly, the tradeoff between noise reduction (better with filters with wide support in the time domain) and localization of detected changes (better with filters with narrow support) is expressed in the well-known uncertainty principle and can be addressed optimally within a time-frequency framework. Unsurprisingly, a large number of edge-detection algorithms have been proposed that make use of wavelet decompositions and similar techniques. We are developing this framework in part to be applied to a particular set of climate data from Greenland; we will present results from this application as well as from tests with

  14. Edge Simulation Laboratory Progress and Plans

    SciTech Connect

    Cohen, R

    2007-06-05

    The Edge Simulation Laboratory (ESL) is a project to develop a gyrokinetic code for MFE edge plasmas based on continuum (Eulerian) techniques. ESL is a base-program activity of OFES, with an allied algorithm research activity funded by the OASCR base math program. ESL OFES funds directly support about 0.8 FTE of career staff at LLNL, a postdoc and a small fraction of an FTE at GA, and a graduate student at UCSD. In addition the allied OASCR program funds about 1/2 FTE each in the computations directorates at LBNL and LLNL. OFES ESL funding for LLNL and UCSD began in fall 2005, while funding for GA and the math team began about a year ago. ESL's continuum approach is a complement to the PIC-based methods of the CPES Project, and was selected (1) because of concerns about noise issues associated with PIC in the high-density-contrast environment of the edge pedestal, (2) to be able to exploit advanced numerical methods developed for fluid codes, and (3) to build upon the successes of core continuum gyrokinetic codes such as GYRO, GS2 and GENE. The ESL project presently has three components: TEMPEST, a full-f, full-geometry (single-null divertor, or arbitrary-shape closed flux surfaces) code in E, {mu} (energy, magnetic-moment) coordinates; EGK, a simple-geometry rapid-prototype code, presently of; and the math component, which is developing and implementing algorithms for a next-generation code. Progress would be accelerated if we could find funding for a fourth, computer science, component, which would develop software infrastructure, provide user support, and address needs for data handing and analysis. We summarize the status and plans for the three funded activities.

  15. Edge ambipolar potential in toroidal fusion plasmas

    SciTech Connect

    Spizzo, G. Vianello, N.; Agostini, M.; Puiatti, M. E.; Scarin, P.; Spolaore, M.; Terranova, D.; White, R. B.; Abdullaev, S. S.; Schmitz, O.; Cavazzana, R.; Ciaccio, G.

    2014-05-15

    A series of issues with toroidally confined fusion plasmas are related to the generation of 3D flow patterns by means of edge magnetic islands, embedded in a chaotic field and interacting with the wall. These issues include the Greenwald limit in Tokamaks and reversed-field pinches, the collisionality window for ELM mitigation with the resonant magnetic perturbations (RMPs) in Tokamaks, and edge islands interacting with the bootstrap current in stellarators. Measurements of the 2D map of the edge electric field E{sup r}(r=a,θ,ϕ) in the RFX reversed-field pinch show that E{sup r} has the same helicity of the magnetic islands generated by a m/n perturbation: in fact, defining the helical angle u=mθ−nϕ+ωt, maps show a sinusoidal dependence as a function of u, E{sup r}=E{sup ~r}sin u. The associated E × B flow displays a huge convective cell with v(a)≠0 which, in RFX and near the Greenwald limit, determines a stagnation point for density and a reversal of the sign of E{sup r}. From a theoretical point of view, the question is how a perturbed toroidal flux of symmetry m/n gives rise to an ambipolar potential Φ=Φ{sup ~}sin u. On the basis of a model developed with the guiding center code ORBIT and applied to RFX and the TEXTOR tokamak, we will show that the presence of an m/n perturbation in any kind of device breaks the toroidal symmetry with a drift proportional to the gyroradius ρ, thus larger for ions (ρ{sub i} ≫ ρ{sub e}). Immediately, an ambipolar potential arises to balance the drifts, with the same symmetry as the original perturbation.

  16. Viscosity in the edge of tokamak plasmas

    NASA Astrophysics Data System (ADS)

    Stacey, W. M.

    1993-05-01

    A fluid representation of viscosity has been incorporated into a set of fluid equations that are maximally ordered in the 'short radial gradient scale length' (srgsl) ordering that is appropriate for the edge of tokamak plasmas. The srgsl ordering raises viscous drifts and other viscous terms to leading order and fundamentally alters the character of the fluid equations. A leasing order viscous drift is identified. Viscous-driven radial particle and energy fluxes in the scrape-off layer and divertor channel are estimated to have an order unity effect in reducing radial peaking of energy fluxes transported along the field lines to divertor collector plates.

  17. Distributed Antenna-Coupled Transition Edge Sensors

    NASA Technical Reports Server (NTRS)

    Day, Peter K.; LeDuc, Henry G.; Lee, Richard A. M.; Dowell, C. Darren; Zmuidzinas, Jonas

    2006-01-01

    We describe progress toward realizing a new architecture for focal plane arrays for the Submillimeter and Far- Infrared (FIR) bands. This architecture is based on a detector design utilizing distributed hot{electron transition edge sensors (TES) coupled to slot antenna elements. Arrays utilizing this type of detector can be considerably easier to manufacture than membrane-isolated TES arrays, because the need for micro-machining is eliminated. We present background and rationale for this new array architecture and details of a new antenna design for an imaging polarimeter, which yields greater bandwidth than past designs. In addition, we describe a cryogenic facility for testing these arrays.

  18. Chiral thermoelectrics with quantum Hall edge states.

    PubMed

    Sánchez, Rafael; Sothmann, Björn; Jordan, Andrew N

    2015-04-10

    The thermoelectric properties of a three-terminal quantum Hall conductor are investigated. We identify a contribution to the thermoelectric response that relies on the chirality of the carrier motion rather than on spatial asymmetries. The Onsager matrix becomes maximally asymmetric with configurations where either the Seebeck or the Peltier coefficients are zero while the other one remains finite. Reversing the magnetic field direction exchanges these effects, which originate from the chiral nature of the quantum Hall edge states. The possibility to generate spin-polarized currents in quantum spin Hall samples is discussed. PMID:25910147

  19. Chiral Thermoelectrics with Quantum Hall Edge States

    NASA Astrophysics Data System (ADS)

    Sánchez, Rafael; Sothmann, Björn; Jordan, Andrew N.

    2015-04-01

    The thermoelectric properties of a three-terminal quantum Hall conductor are investigated. We identify a contribution to the thermoelectric response that relies on the chirality of the carrier motion rather than on spatial asymmetries. The Onsager matrix becomes maximally asymmetric with configurations where either the Seebeck or the Peltier coefficients are zero while the other one remains finite. Reversing the magnetic field direction exchanges these effects, which originate from the chiral nature of the quantum Hall edge states. The possibility to generate spin-polarized currents in quantum spin Hall samples is discussed.

  20. Large Format Transition Edge Sensor Microcalorimeter Arrays

    NASA Technical Reports Server (NTRS)

    Chervenak, J. A.; Adams, J. A.; Bandler, S. b.; Busch, S. E.; Eckart, M. E.; Ewin, A. E.; Finkbeiner, F. M.; Kilbourne, C. A.; Kelley, R. L.; Porst, J. P.; Porter, F. S.; Ray, C.; Sadleir, J. E.; Smith, S. J.; Wassell, E. J.

    2012-01-01

    We have produced a variety of superconducting transition edge sensor array designs for microcalorimetric detection of x-rays. Designs include kilopixel scale arrays of relatively small sensors (approximately 75 micron pitch) atop a thick metal heat sinking layer as well as arrays of membrane-isolated devices on 250 micron and up to 600 micron pitch. We discuss fabrication and performance of microstripline wiring at the small scales achieved to date. We also address fabrication issues with reduction of absorber contact area in small devices.

  1. Hermetic edge sealing of photovoltaic modules

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The edge sealing technique is accomplished by a combination of a chemical bond between glass and aluminum, formed by electrostatic bonding, and a metallurgical bond between aluminum and aluminum, formed by ultrasonic welding. Such a glass to metal seal promises to provide a low cost, long lifetime, highly effective hermetic seal which can protect module components from severe environments. Development of the sealing techniques and demonstration of their effectiveness by fabricating a small number of dummy modules, up to eight inches square in size, and testing them for hermeticity using helium leak testing methods are reviewed. Non-destructive test methods are investigated.

  2. Features of plastics edge cutting machining

    NASA Astrophysics Data System (ADS)

    Handozhko, A. V.; Shcherbakov, A. N.; Zaharov, L. A.; Gavrilenko, T. V.

    2016-04-01

    This article describes the features of pieces from thermoplastic materials in the form of electrical insulators cut by a disk edge tool. The problems in question are possible defects arising during machining and technological conditions that reduce their quantity. The necessity of required machining conditions matching substantiated in accordance with a specific grade of the material which is treated. Equipment and machining attachments, developed for experimental studies, determine the rational conditions of plastic electrical insulators machining. As a result of experiments the dependences of cut face quality parameters of plastics are obtained by machining conditions. The obtained results allowed us to make valid conclusions and recommendations.

  3. Rimmed and edge thickened Stodola shaped flywheel

    DOEpatents

    Kulkarni, Satish V.; Stone, Richard G.

    1983-01-01

    A flywheel (10) is described that is useful for energy storage in a hybrid vehicle automotive power system or in some stationary applications. The flywheel (10) has a body (15) composed of essentially planar isotropic high strength material. The flywheel (10) body (15) is enclosed by a rim (50) of circumferentially wound fiber (2) embedded in resin (3). The rim (50) promotes flywheel (10) safety and survivability. The flywheel (10) has a truncated and edge thickened Stodola shape designed to optimize system mass and energy storage capability.

  4. Catastrophe optics of sharp-edge diffraction.

    PubMed

    Borghi, Riccardo

    2016-07-01

    A classical problem of diffraction theory, namely plane wave diffraction by sharp-edge apertures, is here reformulated from the viewpoint of the fairly new subject of catastrophe optics. On using purely geometrical arguments, properly embedded into a wave optics context, uniform analytical estimates of the diffracted wavefield at points close to fold caustics are obtained, within paraxial approximation, in terms of the Airy function and its first derivative. Diffraction from parabolic apertures is proposed to test reliability and accuracy of our theoretical predictions.

  5. The multiple junction edge illuminated solar cell

    NASA Technical Reports Server (NTRS)

    Sater, B. I.; Brandhorst, H. W., Jr.; Riley, T. J.; Hart, R. E., Jr.

    1973-01-01

    The multiple junction edge illuminated solar cell was devised for high voltage low current applications. Devices to be flight tested in early 1974 with 96 series connected PNN+ junctions in a 2 cm X 2.3 cm size deliver 36 volts at 1 milliampere. Test data of M-J cells fabricated with resistivities of 10, 50, 100, 200, 450, and 1000 ohm cm silicon are presented and problem areas are discussed. An additional potential application of the M-J cell lies in ultilization of its high intensity performance that has been demonstrated at levels in excess of 100 AMO suns.

  6. Entanglement entropy of electromagnetic edge modes.

    PubMed

    Donnelly, William; Wall, Aron C

    2015-03-20

    The vacuum entanglement entropy of Maxwell theory, when evaluated by standard methods, contains an unexpected term with no known statistical interpretation. We resolve this two-decades old puzzle by showing that this term is the entanglement entropy of edge modes: classical solutions determined by the electric field normal to the entangling surface. We explain how the heat kernel regularization applied to this term leads to the negative divergent expression found by Kabat. This calculation also resolves a recent puzzle concerning the logarithmic divergences of gauge fields in 3+1 dimensions. PMID:25839259

  7. Influence of edge on predator prey distribution and abundance

    NASA Astrophysics Data System (ADS)

    Ferguson, Steven H.

    2004-03-01

    I investigated the effect of spatial configuration on distribution and abundance of invertebrate trophic groups by counting soil arthropods under boxes (21 × 9.5 cm) arranged in six different patterns that varied in the amount of edge (137-305 cm). I predicted fewer individuals from the consumer trophic group (Collembola) in box groups with greater amount of edge. This prediction was based on the assumption that predators (mites, ants, spiders, centipedes) select edge during foraging and thereby reduce abundance of the less mobile consumer group under box patterns with greater edge. Consumer abundance (Collembola) was not correlated with amount of edge. Among the predator groups, mite, ant and centipede abundance related to the amount of edge of box groups. However, in contrast to predictions, abundance of these predators was negatively correlated with amount of edge in box patterns. All Collembola predators, with the exception of ants, were less clumped in distribution than Collembola. The results are inconsistent with the view that predators used box edges to predate the less mobile consumer trophic group. Alternative explanations for the spatial patterns other than predator-prey relations include (1) a negative relationship between edge and moisture, (2) a positive relationship between edge and detritus decomposition (i.e. mycelium as food for the consumer group), and (3) a negative relationship between edge and the interstices between adjacent boxes. Landscape patterns likely affect microclimate, food, and predator-prey relations and, therefore, future experimental designs need to control these factors individually to distinguish among alternative hypotheses.

  8. Edge detection depends on achromatic channel in Drosophila melanogaster.

    PubMed

    Zhou, Yanqiong; Ji, Xiaoxiao; Gong, Haiyun; Gong, Zhefeng; Liu, Li

    2012-10-01

    Edges represent important information in object recognition, and thus edge detection is crucial for animal survival. Various types of edges result from visual contrast, such as luminance contrast and color contrast. So far, the molecular and neural mechanisms underlying edge detection and the relationship between different edge information-processing pathways have been largely undemonstrated. In the present study, using a color light-emitting-diode-based Buridan's paradigm, we demonstrated that a blue/green demarcation is able to generate edge-orientation behavior in the adult fly. There is a blue/green intensity ratio, the so-called point of equal luminance, at which wild-type flies did not show obvious orientation behavior towards edges. This suggests that orientation behavior towards edges is dependent on luminance contrast in Drosophila. The results of mutants ninaE(17) and sev(LY3);rh5(2);rh6(1) demonstrated that achromatic R1-R6 photoreceptor cells, but not chromatic R7/R8 photoreceptor cells, were necessary for orientation behavior towards edges. Moreover, ectopic expression of rhodopsin 4 (Rh4), Rh5 or Rh6 could efficiently restore the edge-orientation defect in the ninaE(17) mutant. Altogether, our results show that R1-R6 photoreceptor cells are both necessary and sufficient for orientation behavior towards edges in Drosophila. PMID:22735352

  9. Computing the Edge-Neighbour-Scattering Number of Graphs

    NASA Astrophysics Data System (ADS)

    Wei, Zongtian; Qi, Nannan; Yue, Xiaokui

    2013-11-01

    A set of edges X is subverted from a graph G by removing the closed neighbourhood N[X] from G. We denote the survival subgraph by G=X. An edge-subversion strategy X is called an edge-cut strategy of G if G=X is disconnected, a single vertex, or empty. The edge-neighbour-scattering number of a graph G is defined as ENS(G) = max{ω(G/X)-|X| : X is an edge-cut strategy of G}, where w(G=X) is the number of components of G=X. This parameter can be used to measure the vulnerability of networks when some edges are failed, especially spy networks and virus-infected networks. In this paper, we prove that the problem of computing the edge-neighbour-scattering number of a graph is NP-complete and give some upper and lower bounds for this parameter.

  10. Using new edges for anomaly detection in computer networks

    DOEpatents

    Neil, Joshua Charles

    2015-05-19

    Creation of new edges in a network may be used as an indication of a potential attack on the network. Historical data of a frequency with which nodes in a network create and receive new edges may be analyzed. Baseline models of behavior among the edges in the network may be established based on the analysis of the historical data. A new edge that deviates from a respective baseline model by more than a predetermined threshold during a time window may be detected. The new edge may be flagged as potentially anomalous when the deviation from the respective baseline model is detected. Probabilities for both new and existing edges may be obtained for all edges in a path or other subgraph. The probabilities may then be combined to obtain a score for the path or other subgraph. A threshold may be obtained by calculating an empirical distribution of the scores under historical conditions.

  11. Coaxial connector for use with printed circuit board edge connector

    DOEpatents

    Howard, Donald R.; MacGill, Robert A.

    1989-01-01

    A coaxial cable connector for interfacing with an edge connector for a printed circuit board whereby a coaxial cable can be interconnected with a printed circuit board through the edge connector. The coaxial connector includes a body having two leg portions extending from one side for receiving the edge connector therebetween, and a tubular portion extending from an opposing side for receiving a coaxial cable. A cavity within the body receives a lug of the edge connector and the center conductor of the coaxial cable. Adjacent lugs of the edge connector can be bend around the edge connector housing to function as spring-loaded contacts for receiving the coaxial connector. The lugs also function to facilitate shielding of the center conductor where fastened to the edge connector lug.

  12. Edge states in confined active fluids

    NASA Astrophysics Data System (ADS)

    Souslov, Anton; Vitelli, Vincenzo

    Recently, topologically protected edge modes have been proposed and realized in both mechanical and acoustic metamaterials. In one class of such metamaterials, Time-Reversal Symmetry is broken, and, to achieve this TRS breaking in mechanical and acoustic systems, an external energy input must be used. For example, motors provide a driving force that uses energy and, thus, explicitly break TRS. As a result, motors have been used as an essential component in the design of topological metamaterials. By contrast, we explore the design of topological metamaterials that use a class of far-from-equilibrium liquids, called polar active liquids, that spontaneously break TRS. We thus envision the confinement of a polar active liquid to a prescribed geometry in order to realize topological order with broken time-reversal symmetry. We address the design of the requisite geometries, for example a regular honeycomb lattice composed of annular channels, in which the active liquid may be confined. We also consider the physical character of the active liquid that, when introduced into the prescribed geometry, will spontaneously form the flow pattern of a metamaterial with topologically protected edge states. Finally, we comment on potential experimental realizations of such metamaterials.

  13. The Stochastic Edge in Adaptive Evolution

    PubMed Central

    Brunet, Éric; Rouzine, Igor M.; Wilke, Claus O.

    2008-01-01

    In a recent article, Desai and Fisher proposed that the speed of adaptation in an asexual population is determined by the dynamics of the stochastic edge of the population, that is, by the emergence and subsequent establishment of rare mutants that exceed the fitness of all sequences currently present in the population. Desai and Fisher perform an elaborate stochastic calculation of the mean time τ until a new class of mutants has been established and interpret 1/τ as the speed of adaptation. As they note, however, their calculations are valid only for moderate speeds. This limitation arises from their method to determine τ: Desai and Fisher back extrapolate the value of τ from the best-fit class's exponential growth at infinite time. This approach is not valid when the population adapts rapidly, because in this case the best-fit class grows nonexponentially during the relevant time interval. Here, we substantially extend Desai and Fisher's analysis of the stochastic edge. We show that we can apply Desai and Fisher's method to high speeds by either exponentially back extrapolating from finite time or using a nonexponential back extrapolation. Our results are compatible with predictions made using a different analytical approach (Rouzine et al.) and agree well with numerical simulations. PMID:18493075

  14. Shape Optimization for Trailing Edge Noise Control

    NASA Astrophysics Data System (ADS)

    Marsden, Alison; Wang, Meng; Mohammadi, Bijan; Moin, Parviz

    2001-11-01

    Noise generated by turbulent boundary layers near the trailing edge of lifting surfaces continues to pose a challenge for many applications. In this study, we explore noise reduction strategies through shape optimization. A gradient based shape design method is formulated and implemented for use with large eddy simulation of the flow over an airfoil. The cost function gradient is calculated using the method of incomplete sensitivities (Mohammadi and Pironneau 2001 ph Applied shape Optimization for Fluids, Oxford Univ. Press). This method has the advantage that effects of geometry changes on the flow field can be neglected when computing the gradient of the cost function, making it far more cost effective than solving the full adjoint problem. Validation studies are presented for a model problem of the unsteady laminar flow over an acoustically compact airfoil. A section of the surface is allowed to deform and the cost function is derived based on aeroacoustic theroy. Rapid convergence of the trailing-edge shape and significant reduction of the noise due to vortex shedding and wake instability have been achieved. The addition of constraints and issues of extension to fully turbulent flows past an acoustically noncompact airfoil are also discussed.

  15. LES tests on airfoil trailing edge serration

    NASA Astrophysics Data System (ADS)

    Zhu, Wei Jun; Shen, Wen Zhong

    2016-09-01

    In the present study, a large number of acoustic simulations are carried out for a low noise airfoil with different Trailing Edge Serrations (TES). The Ffowcs Williams-Hawkings (FWH) acoustic analogy is used for noise prediction at trailing edge. The acoustic solver is running on the platform of our in-house incompressible flow solver EllipSys3D. The flow solution is first obtained from the Large Eddy Simulation (LES), the acoustic part is then carried out based on the instantaneous hydrodynamic pressure and velocity field. To obtain the time history data of sound pressure, the flow quantities are integrated around the airfoil surface through the FWH approach. For all the simulations, the chord based Reynolds number is around 1.5x106. In the test matrix, the effects from angle of attack, the TE flap angle, the length/width of the TES are investigated. Even though the airfoil under investigation is already optimized for low noise emission, most numerical simulations and wind tunnel experiments show that the noise level is further decreased by adding the TES device.

  16. Investigation of a Laminar Flow Leading Edge

    NASA Technical Reports Server (NTRS)

    Drake, Aaron; Kennelly, Robert A., Jr.; Koga, Dennis J.; Westphal, Russell V.; Zuniga, Fanny

    1994-01-01

    The recent resurgence of interest in utilizing laminar flow on aircraft surfaces for reduction in skin friction drag has generated a considerable amount of research in natural laminar flow (NLF) and hybrid laminar flow control (HLFC) on transonic aircraft wings. This research has focused primarily on airfoil design and understanding transition behavior with little concern for the surface imperfections and manufacturing variations inherent to most production aircraft. In order for laminar flow to find wide-spread use on production aircraft, techniques for constructing the wings must be found such that the large surface imperfections present in the leading edge region of current aircraft do not occur. Toward this end, a modification to existing leading edge construction techniques was devised such that the resulting surface did not contain large gaps and steps as are common on current production aircraft of this class. A lowspeed experiment was first conducted on a simulation of the surface that would result from this construction technique. Preston tube measurements of the boundary layer downstream of the simulated joint and flow visualization using sublimation chemicals validated the literature on the effects of steps on a laminar boundary layer. These results also indicated that the construction technique was indeed compatible with laminar flow. In order to fully validate the compatibility of this construction technique with laminar flow, thus proving that it is possible to build wings that are smooth enough to be used on business jets and light transports in a manner compatible with laminar flow, a flight experiment is being conducted. In this experiment Mach number and Reynolds number will be matched in a real flight environment. The experiment is being conducted using the NASA Dryden F-104 Flight Test Fixture (FTF). The FTF is a low aspect ratio ventral fin mounted beneath an F-104G research aircraft. A new nose shape was designed and constructed for this

  17. Photon Counting Using Edge-Detection Algorithm

    NASA Technical Reports Server (NTRS)

    Gin, Jonathan W.; Nguyen, Danh H.; Farr, William H.

    2010-01-01

    New applications such as high-datarate, photon-starved, free-space optical communications require photon counting at flux rates into gigaphoton-per-second regimes coupled with subnanosecond timing accuracy. Current single-photon detectors that are capable of handling such operating conditions are designed in an array format and produce output pulses that span multiple sample times. In order to discern one pulse from another and not to overcount the number of incoming photons, a detection algorithm must be applied to the sampled detector output pulses. As flux rates increase, the ability to implement such a detection algorithm becomes difficult within a digital processor that may reside within a field-programmable gate array (FPGA). Systems have been developed and implemented to both characterize gigahertz bandwidth single-photon detectors, as well as process photon count signals at rates into gigaphotons per second in order to implement communications links at SCPPM (serial concatenated pulse position modulation) encoded data rates exceeding 100 megabits per second with efficiencies greater than two bits per detected photon. A hardware edge-detection algorithm and corresponding signal combining and deserialization hardware were developed to meet these requirements at sample rates up to 10 GHz. The photon discriminator deserializer hardware board accepts four inputs, which allows for the ability to take inputs from a quadphoton counting detector, to support requirements for optical tracking with a reduced number of hardware components. The four inputs are hardware leading-edge detected independently. After leading-edge detection, the resultant samples are ORed together prior to deserialization. The deserialization is performed to reduce the rate at which data is passed to a digital signal processor, perhaps residing within an FPGA. The hardware implements four separate analog inputs that are connected through RF connectors. Each analog input is fed to a high-speed 1

  18. School Violence, School Differences and School Discourses

    ERIC Educational Resources Information Center

    Watkins, Chris; Mauthner, Melanie; Hewitt, Roger; Epstein, Debbie; Leonard, Diana

    2007-01-01

    This article highlights one strand of a study which investigated the concept of the violence-resilient school. In six inner-city secondary schools, data on violent incidents in school and violent crime in the neighbourhood were gathered, and compared with school practices to minimise violence, accessed through interviews. Some degree of…

  19. Procedural guidance using advance imaging techniques for percutaneous edge-to-edge mitral valve repair.

    PubMed

    Quaife, Robert A; Salcedo, Ernesto E; Carroll, John D

    2014-02-01

    The complexity of structural heart disease interventions such as edge-to edge mitral valve repair requires integration of multiple highly technical imaging modalities. Real time imaging with 3-dimensional (3D) echocardiography is a relatively new technique that first, allows clear volumetric imaging of target structures such as the mitral valve for both pre-procedural diagnosis and planning in patients with degenerative or functional mitral valve regurgitation. Secondly it provides intra-procedural, real-time panoramic volumetric 3D view of structural heart disease targets that facilitates eye-hand coordination while manipulating devices within the heart. X-ray fluoroscopy and RT 3D TEE images are used in combination to display specific targets and movement of catheter based technologies in 3D space. This integration requires at least two different image display monitors and mentally fusing the individual datasets by the operator. Combined display technology such as this, allow rotation and orientation of both dataset perspectives necessary to define targets and guidance of structural disease device procedures. The inherently easy concept of direct visual feedback and eye-hand coordination allows safe and efficient completion of MitraClip procedures. This technology is now merged into a single structural heart disease guidance mode called EchoNavigator(TM) (Philips Medical Imaging Andover, MA). These advanced imaging techniques have revolutionized the field of structural heart disease interventions and this experience is exemplified by a cooperative imaging approach used for guidance of edge-to-edge mitral valve repair procedures.

  20. At Water's Edge: Students Study Their Rivers.

    ERIC Educational Resources Information Center

    Williams, Robert; And Others

    1993-01-01

    Although the Great Flood of 1993 has dramatically reminded us never to take rivers for granted, it has also underlined the need to learn more about rivers and the environment in general. Rivers Project, an interdisciplinary high school curriculum, allows science, social studies, and English teachers to integrate curriculum in a way that encourages…

  1. A Long Walk to The Water's Edge

    ERIC Educational Resources Information Center

    Fortner, Rosanne W.

    2005-01-01

    Middle school students examine data from the Great Lakes region, assess impact of climate changes, and relate climate and water processes in a concept map. After learning how lake water levels will likely decline, they listen to a story about a grandparent revisiting the lakeshore with a grandchild. In the role of the grandparent and then of the…

  2. WCCC's Cutting-Edge Cosmetology Program

    ERIC Educational Resources Information Center

    Allen, Peg

    2008-01-01

    This article describes how a relatively small southwest Ohio career and technical education (CTE) school is making a big impression on students, their future employees, and the industry with its near 100 percent passage rate of the Ohio Board of Cosmetology exam every year and a matching placement rate. With a mission to prepare youths and adults…

  3. Collaborative Edge: How Helping Others Helps You

    ERIC Educational Resources Information Center

    Hargreaves, Andy; Shirley, Dennis; Harris, Alma; Boyle, Alan

    2010-01-01

    Teachers might be working significantly more with one another, but principals are not. Superintendents might bring principals together for district meetings or even to expose their performance results to colleagues in public, but principal collaboration is too often trumped by district control. Even worse, more and more schools and their…

  4. School Climate.

    ERIC Educational Resources Information Center

    Lindelow, John; Mazzarella, Jo Ann

    Chapter 7 of a volume on school leadership, this chapter defines, describes, and suggests ways to improve climate at the school building level. After citing a number of definitions of school climate, the authors conclude that school climate is the feel an individual gets from experiences within a school system, or the global summation of the…

  5. From Flashes to Edges to Objects: Recovery of Local Edge Fragments Initiates Spatiotemporal Boundary Formation

    PubMed Central

    Erlikhman, Gennady; Kellman, Philip J.

    2016-01-01

    Spatiotemporal boundary formation (SBF) is the perception of illusory boundaries, global form, and global motion from spatially and temporally sparse transformations of texture elements (Shipley and Kellman, 1993a, 1994; Erlikhman and Kellman, 2015). It has been theorized that the visual system uses positions and times of element transformations to extract local oriented edge fragments, which then connect by known interpolation processes to produce larger contours and shapes in SBF. To test this theory, we created a novel display consisting of a sawtooth arrangement of elements that disappeared and reappeared sequentially. Although apparent motion along the sawtooth would be expected, with appropriate spacing and timing, the resulting percept was of a larger, moving, illusory bar. This display approximates the minimal conditions for visual perception of an oriented edge fragment from spatiotemporal information and confirms that such events may be initiating conditions in SBF. Using converging objective and subjective methods, experiments showed that edge formation in these displays was subject to a temporal integration constraint of ~80 ms between element disappearances. The experiments provide clear support for models of SBF that begin with extraction of local edge fragments, and they identify minimal conditions required for this process. We conjecture that these results reveal a link between spatiotemporal object perception and basic visual filtering. Motion energy filters have usually been studied with orientation given spatially by luminance contrast. When orientation is not given in static frames, these same motion energy filters serve as spatiotemporal edge filters, yielding local orientation from discrete element transformations over time. As numerous filters of different characteristic orientations and scales may respond to any simple SBF stimulus, we discuss the aperture and ambiguity problems that accompany this conjecture and how they might be resolved

  6. Reinterpreting the Sharp Edges of Planetary Rings

    NASA Astrophysics Data System (ADS)

    Rimlinger, Thomas; Hamilton, Douglas P.; Hahn, Joseph M.

    2016-10-01

    Narrow ringlets are found throughout the Solar System and are typically 1-100 km wide. Angular momentum, L, is the key to understanding how narrow rings remain confined; L2 ∝ a(1 – e2) for semimajor axis a and eccentricity e. In a circular ring, L conservation demands that the ring quickly spread apart when some colliding particles lose energy while others gain it. By contrast, in an eccentric ring, energy loss and the associated decay of the average semi-major axes can be offset by a decrease in the average eccentricity. We argue that a ring's lifetime can be greatly extended if particles arrange themselves in this way (Borderies et al. 1984). The key difference of our model, however, is that rings need not be shepherded and can confine themselves provided they are sufficiently eccentric. Satellites merely extend the rings' lifespans by pumping up their eccentricities.This confinement mechanism can explain the existence and longevity of narrow ringlets in a variety of contexts. Saturn's Titan ringlet, which is quite circular, may nevertheless be able to confine itself indefinitely if its eccentricity decay is balanced by the increase from the resonance with Titan. Preliminary simulations presented by Rimlinger et al. at this year's DDA Conference have verified that this ring can self-confine even in the absence of any satellite; we update these findings with new results that include the effects of Titan. Furthermore, Mimas' resonance with the edge of the B ring may excite its higher order modes to similar effect. We update the findings of Hahn and Spitale (2013), who used artificial forces to confine the B ring's edge, and suggest that with a suitable viscosity and density, no such forces will be needed to keep the edge sharp. Finally, a ring that is "born" with a sufficiently high eccentricity may live for hundreds of millions or even billions of years in isolation if the rate of decay is slow enough. We present simulations exploring such a scenario.

  7. Extending the Classroom: Transforming a School through Experiential Education

    ERIC Educational Resources Information Center

    Mierke, Sara

    2013-01-01

    Even the most traditional independent schools have a starting point for expanding or integrating experiential education. Hawken was founded in 1915 as an alternative to existing traditional private education options for boys in Cleveland. James A. Hawken, a progressive New York educator, founded the school in a small house on the edge of…

  8. Wisconsin High Schools Learn from New PISA Test: International Comparison Drives Efforts to Improve

    ERIC Educational Resources Information Center

    Borsuk, Alan J.

    2015-01-01

    This article explores Kettle Moraine High School's experience of participating in the PISA-based test, known in the U.S. as the OECD Test for Schools. The high school is located on the western edge of Milwaukee. Starting with a trial run in 2012 that involved more than 100 U.S. schools, the OECD Test for Schools has been offered to individual…

  9. 18th Annual School Construction Report, 2013

    ERIC Educational Resources Information Center

    Abramson, Paul

    2013-01-01

    The bottom line on school construction in 2012 is that total spending edged up slightly from the previous year, (to $12.9 billion from $12.2 billion), but the spending for new schools declined from $6.9 billion to $6.177 billion. The increase in overall spending was attributable to more spending for additions and a major increase in spending for…

  10. Independence of color and luminance edges in natural scenes.

    PubMed

    Hansen, Thorsten; Gegenfurtner, Karl R

    2009-01-01

    Form vision is traditionally regarded as processing primarily achromatic information. Previous investigations into the statistics of color and luminance in natural scenes have claimed that luminance and chromatic edges are not independent of each other and that any chromatic edge most likely occurs together with a luminance edge of similar strength. Here we computed the joint statistics of luminance and chromatic edges in over 700 calibrated color images from natural scenes. We found that isoluminant edges exist in natural scenes and were not rarer than pure luminance edges. Most edges combined luminance and chromatic information but to varying degrees such that luminance and chromatic edges were statistically independent of each other. Independence increased along successive stages of visual processing from cones via postreceptoral color-opponent channels to edges. The results show that chromatic edge contrast is an independent source of information that can be linearly combined with other cues for the proper segmentation of objects in natural and artificial vision systems. Color vision may have evolved in response to the natural scene statistics to gain access to this independent information. PMID:19152717

  11. Development of Tool Edge Temperature Measurement Method in Wet Cutting

    NASA Astrophysics Data System (ADS)

    Nishimoto, Hideto; Tanaka, Ryutaro; Hosokawa, Akira; Ueda, Takashi; Furumoto, Tatsuaki

    In this paper, the measurement method of tool edge temperature using a two-color pyrometer with an optical fiber in wet cutting is proposed. Using the proposed method, the high pressure air supplied from the small hole where an optical fiber is inserted prevents coolant from adhering to the optical fiber edge and makes temperature measuring possible. The influence of this supplied air pressure on the tool edge temperature is negligible in the 0.05Mpa to 0.6MPa range. In this way, the temperature of CBN and PCD tool edge is measured in wet cutting of Ti-6Al-4V. As a result, the tool edge temperature increases rapidly with the increase of cutting speed. In dry cutting, PCD tool edge temperature is almost 100 °C lower compared with CBN tool edge temperature. By coolant supply, PCD tool edge temperature decreases greatly. For example, when cutting speed is set at 300m/min, PCD tool edge temperature decreases by 350°C, while CBN tool edge temperature decreases by only 70°C.

  12. Edge effects on the electronic properties of phosphorene nanoribbons

    SciTech Connect

    Peng, Xihong; Copple, Andrew; Wei, Qun

    2014-10-14

    Two dimensional few-layer black phosphorus crystal structures have recently been fabricated and have demonstrated great potential in electronic applications. In this work, we employed first principles density functional theory calculations to study the edge and quantum confinement effects on the electronic properties of the phosphorene nanoribbons (PNR). Different edge functionalization groups, such as H, F, Cl, OH, O, S, and Se, in addition to a pristine case were studied for a series of ribbon widths up to 3.5 nm. It was found that the armchair-PNRs (APNRs) are semiconductors for all edge groups considered in this work. However, the zigzag-PNRs (ZPNRs) show either semiconductor or metallic behavior in dependence on their edge chemical species. Family 1 edges (i.e., H, F, Cl, OH) form saturated bonds with P atoms in the APNRs and ZPNRs, and the edge states keep far away from the band gap. However, Family 2 edges (pristine, O, S, Se) form weak unsaturated bonds with the p{sub z} orbital of the phosphorus atoms and bring edge states within the band gap of the ribbons. For the ZPNRs, the edge states of Family 2 are present around the Fermi level within the band gap, which close up the band gap of the ZPNRs. For the APNRs, these edge states are located at the bottom of the conduction band and result in a reduced band gap.

  13. Edge effects on the electronic properties of phosphorene nanoribbons

    NASA Astrophysics Data System (ADS)

    Peng, Xihong; Copple, Andrew; Wei, Qun

    2014-10-01

    Two dimensional few-layer black phosphorus crystal structures have recently been fabricated and have demonstrated great potential in electronic applications. In this work, we employed first principles density functional theory calculations to study the edge and quantum confinement effects on the electronic properties of the phosphorene nanoribbons (PNR). Different edge functionalization groups, such as H, F, Cl, OH, O, S, and Se, in addition to a pristine case were studied for a series of ribbon widths up to 3.5 nm. It was found that the armchair-PNRs (APNRs) are semiconductors for all edge groups considered in this work. However, the zigzag-PNRs (ZPNRs) show either semiconductor or metallic behavior in dependence on their edge chemical species. Family 1 edges (i.e., H, F, Cl, OH) form saturated bonds with P atoms in the APNRs and ZPNRs, and the edge states keep far away from the band gap. However, Family 2 edges (pristine, O, S, Se) form weak unsaturated bonds with the pz orbital of the phosphorus atoms and bring edge states within the band gap of the ribbons. For the ZPNRs, the edge states of Family 2 are present around the Fermi level within the band gap, which close up the band gap of the ZPNRs. For the APNRs, these edge states are located at the bottom of the conduction band and result in a reduced band gap.

  14. Green's function approach to edge states in transition metal dichalcogenides

    NASA Astrophysics Data System (ADS)

    Farmanbar, Mojtaba; Amlaki, Taher; Brocks, Geert

    2016-05-01

    The semiconducting two-dimensional transition metal dichalcogenides MX 2 show an abundance of one-dimensional metallic edges and grain boundaries. Standard techniques for calculating edge states typically model nanoribbons, and require the use of supercells. In this paper, we formulate a Green's function technique for calculating edge states of (semi-)infinite two-dimensional systems with a single well-defined edge or grain boundary. We express Green's functions in terms of Bloch matrices, constructed from the solutions of a quadratic eigenvalue equation. The technique can be applied to any localized basis representation of the Hamiltonian. Here, we use it to calculate edge states of MX 2 monolayers by means of tight-binding models. Aside from the basic zigzag and armchair edges, we study edges with a more general orientation, structurally modifed edges, and grain boundaries. A simple three-band model captures an important part of the edge electronic structures. An 11-band model comprising all valence orbitals of the M and X atoms is required to obtain all edge states with energies in the MX 2 band gap. Here, states of odd symmetry with respect to a mirror plane through the layer of M atoms have a dangling-bond character, and tend to pin the Fermi level.

  15. The Effect of Nozzle Trailing Edge Thickness on Jet Noise

    NASA Technical Reports Server (NTRS)

    Henderson, Brenda; Kinzie, Kevin; Haskin, Henry

    2004-01-01

    The effect of nozzle trailing edge thickness on broadband acoustic radiation and the production of tones is investigated for coannular nozzles. Experiments were performed for a core nozzle trailing edge thickness between 0.38 mm and 3.17 mm. The on-set of discrete tones was found to be predominantly affected by the velocity ratio, the ratio of the fan velocity to the core velocity, although some dependency on trailing edge thickness was also noted. For a core nozzle trailing edge thickness greater than or equal to 0.89 mm, tones were produced for velocity ratios between 0.91 and 1.61. For a constant nozzle trailing edge thickness, the frequency varied almost linearly with the core velocity. The Strouhal number based on the core velocity changed with nozzle trailing edge thickness and varied between 0.16 and 0.2 for the core nozzles used in the experiments. Increases in broadband noise with increasing trailing edge thickness were observed for tone producing and non-tone producing conditions. A variable thickness trailing edge (crenellated) nozzle resulted in no tonal production and a reduction of the broadband trailing edge noise relative to that of the corresponding constant thickness trailing edge.

  16. Edge convection driven by externally applied potentials

    SciTech Connect

    D'Ippolito, D. A.; Myra, J. R.

    2000-08-01

    A theoretical model of convection in collisional tokamak edge and scrape-off-layer plasmas is described. In the linear theory, any mechanism for poloidal and toroidal symmetry breaking of the equilibrium will drive ExB flows; this result stems from the parallel thermal and pressure forces in Ohm's law. In the nonlinear theory, the quadratic coupling of the perturbations leads to quasilinear-type fluxes in the vorticity, density, and temperature equations. If the convection is strong enough, these fluxes lead to an ambipolarity constraint on the equilibrium electric field and to increased transport of particles and energy. The theory shows qualitative agreement with some tokamak experiments in which potential perturbations are externally driven by radio frequency antennas. (c) 2000 American Institute of Physics.

  17. Theory of edge plasma in a spheromak

    SciTech Connect

    Hooper, E.B., LLNL

    1998-05-01

    Properties of the edge plasma in the SSPX spheromak during the plasma formation and sustainment phases are discussed. For the breakdown and formation phase, the main emphasis is on the analysis of possible plasma contamination by impurities from the electrodes of the plasma gun (helicity injector). The issue of an azimuthally uniform breakdown initiation is also discussed. After the plasma settles down in the main vacuum chamber, one has to sustain the current between the electrodes, in order to continuously inject helicity. We discuss properties of the plasma on the field lines intersecting the electrodes. We conclude that the thermal balance of this plasma is maintained by Joule heating competing with parallel heat losses to the electrodes. The resulting plasma temperature is in the range of 15 - 30 eV. Under the expected operational conditions, the ``current`` velocity of the electrons is only slightly below their thermal velocity. Implications of this observation are briefly discussed.

  18. Visible imaging of edge fluctuations in TFTR

    SciTech Connect

    Zweben, S.J.; Medley, S.S.

    1989-03-01

    Images of the visible light emission from the inner wall region of TFTR have been made using a rapidly gated, intensified TV camera. Strong ''filamentation'' of the neutral deuterium D..cap alpha.. light is observed when the camera gating time is <100 ..mu..sec during neutral-beam-heated discharges. These turbulent filaments vary in position randomly vs. time and have a poloidal wavelength of approx.3-5 cm which is much shorter than their parallel wavelength of approx.100 cm. A second and new type of edge fluctuation phenomenon, which we call a ''merfe,'' is also described. Merfes are a regular poloidal pattern of toroidally symmetric, small-scale marfes which move away from the inner midplane during the current decay after neutral beam injection. Some tentative interpretations of these two phenomena are presented. 27 refs., 8 figs.

  19. Wing Leading Edge Joint Laminar Flow Tests

    NASA Technical Reports Server (NTRS)

    Drake, Aaron; Westphal, Russell V.; Zuniga, Fanny A.; Kennelly, Robert A., Jr.; Koga, Dennis J.

    1996-01-01

    An F-104G aircraft at NASA's Dryden Flight Research Center has been equipped with a specially designed and instrumented test fixture to simulate surface imperfections of the type likely to be present near the leading edge on the wings of some laminar flow aircraft. The simulated imperfections consisted of five combinations of spanwise steps and gaps of various sizes. The unswept fixture yielded a pressure distribution similar to that of some laminar flow airfoils. The experiment was conducted at cruise conditions typical for business-jets and light transports: Mach numbers were in the range 0.5-0.8, and unit Reynolds numbers were 1.5-2.5 million per foot. Skin friction measurements indicated that laminar flow was often maintained for some distance downstream of the surface imperfections. Further work is needed to more precisely define transition location and to extend the experiments to swept-wing conditions and a broader range of imperfection geometries.

  20. Wind turbine trailing edge aerodynamic brakes

    SciTech Connect

    Migliore, P G; Miller, L S; Quandt, G A

    1995-04-01

    Five trailing-edge devices were investigated to determine their potential as wind-turbine aerodynamic brakes, and for power modulation and load alleviation. Several promising configurations were identified. A new device, called the spoiler-flap, appears to be the best alternative. It is a simple device that is effective at all angles of attack. It is not structurally intrusive, and it has the potential for small actuating loads. It is shown that simultaneous achievement of a low lift/drag ratio and high drag is the determinant of device effectiveness, and that these attributes must persist up to an angle of attack of 45{degree}. It is also argued that aerodynamic brakes must be designed for a wind speed of at least 45 m/s (100 mph).

  1. The transition-edge EBIT microcalorimeter spectrometer

    NASA Astrophysics Data System (ADS)

    Betancourt-Martinez, Gabriele L.; Adams, Joseph; Bandler, Simon; Beiersdorfer, Peter; Brown, Gregory; Chervenak, James; Doriese, Randy; Eckart, Megan; Irwin, Kent; Kelley, Richard; Kilbourne, Caroline; Leutenegger, Maurice; Porter, F. S.; Reintsema, Carl; Smith, Stephen; Ullom, Joel

    2014-07-01

    The Transition-edge EBIT Microcalorimeter Spectrometer (TEMS) is a 1000-pixel array instrument to be delivered to the Electron Beam Ion Trap (EBIT) facility at the Lawrence Livermore National Laboratory (LLNL) in 2015. It will be the first fully operational array of its kind. The TEMS will utilize the unique capabilities of the EBIT to verify and benchmark atomic theory that is critical for the analysis of high-resolution data from microcalorimeter spectrometers aboard the next generation of x-ray observatories. We present spectra from the present instrumentation at EBIT, as well as our latest results with time-division multiplexing using the current iteration of the TEMS focal plane assembly in our test platform at NASA/GSFC.

  2. Edge Diffusion Flame Propagation and Stabilization Studied

    NASA Technical Reports Server (NTRS)

    Takahashi, Fumiaki; Katta, Viswanath R.

    2004-01-01

    In most practical combustion systems or fires, fuel and air are initially unmixed, thus forming diffusion flames. As a result of flame-surface interactions, the diffusion flame often forms an edge, which may attach to burner walls, spread over condensed fuel surfaces, jump to another location through the fuel-air mixture formed, or extinguish by destabilization (blowoff). Flame holding in combustors is necessary to achieve design performance and safe operation of the system. Fires aboard spacecraft behave differently from those on Earth because of the absence of buoyancy in microgravity. This ongoing in-house flame-stability research at the NASA Glenn Research Center is important in spacecraft fire safety and Earth-bound combustion systems.

  3. Introduction to Solid Edge(TM)

    NASA Technical Reports Server (NTRS)

    Smith, John C.

    1997-01-01

    Solid Edge was conceived and developed to provide breakthrough levels of productivity for engineers and designers by providing tools focused on their daily work. This user-oriented approach led to a focus on five key areas: 1) assembly-focused design, 2) ease of use, 3) plug and play software, 4) superior part modeling, and 5) production drafting. Mechanical designers work primarily with assemblies of parts that together perform a useful function. The parts themselves are principally a consequence of the function of the assembly and the interrelationships between parts. Breakthroughs in productivity will come through a focus on making the design of assemblies easier, with enhanced part design a prerequisite to that. Enhancements already in development are part to part interaction, more assembly features applying to multiple parts, exploded assemblies, assembly playback, enhanced BOM, etc.

  4. Nonlinear magnetohydrodynamics of edge localized mode precursors

    SciTech Connect

    Guo, Z. B.; Wang, Lu; Wang, X. G.

    2015-02-15

    A possible origin of edge-localized-mode (ELM) precursors based on nonlinear ideal peeling-ballooning mode is reported. Via nonlinear variational principle, a nonlinear evolution equation of the radial displacement is derived and solved, analytically. Besides an explosive growth in the initial nonlinear phase, it is found that the local displacement evolves into an oscillating state in the developed nonlinear phase. The nonlinear frequency of the ELM precursors scales as ω{sub pre}∼x{sup 1/3}ξ{sup ^}{sub ψ,in}{sup 2/3}n, with x position in radial direction, ξ{sup ^}{sub ψ,in} strength of initial perturbation, and n toroidal mode number.

  5. Timing discriminator using leading-edge extrapolation

    DOEpatents

    Gottschalk, B.

    1981-07-30

    A discriminator circuit to recover timing information from slow-rising pulses by means of an output trailing edge, a fixed time after the starting corner of the input pulse, which is nearly independent of risetime and threshold setting is described. This apparatus comprises means for comparing pulses with a threshold voltage; a capacitor to be charged at a certain rate when the input signal is one-third threshold voltage, and at a lower rate when the input signal is two-thirds threshold voltage; current-generating means for charging the capacitor; means for comparing voltage capacitor with a bias voltage; a flip-flop to be set when the input pulse reaches threshold voltage and reset when capacitor voltage reaches the bias voltage; and a clamping means for discharging the capacitor when the input signal returns below one-third threshold voltage.

  6. Timing discriminator using leading-edge extrapolation

    DOEpatents

    Gottschalk, Bernard

    1983-01-01

    A discriminator circuit to recover timing information from slow-rising pulses by means of an output trailing edge, a fixed time after the starting corner of the input pulse, which is nearly independent of risetime and threshold setting. This apparatus comprises means for comparing pulses with a threshold voltage; a capacitor to be charged at a certain rate when the input signal is one-third threshold voltage, and at a lower rate when the input signal is two-thirds threshold voltage; current-generating means for charging the capacitor; means for comparing voltage capacitor with a bias voltage; a flip-flop to be set when the input pulse reaches threshold voltage and reset when capacitor voltage reaches the bias voltage; and a clamping means for discharging the capacitor when the input signal returns below one-third threshold voltage.

  7. School Health

    MedlinePlus

    ... else except home. Schools can have a major effect on children's health. Schools can teach children about health, and promote healthy behaviors. Physical education classes give children a chance to get exercise. Schools work to Prevent risky behaviors such as ...

  8. Slope Edge Deformation and Permafrost Dynamics Along the Arctic Shelf Edge, Beaufort Sea, Canada

    NASA Astrophysics Data System (ADS)

    Paull, C. K.; Dallimore, S.; Caress, D. W.; Gwiazda, R.; Lundsten, E. M.; Anderson, K.; Riedel, M.; Melling, H.

    2015-12-01

    The shelf of the Canadian Beaufort Sea is underlain by relict offshore permafrost that formed in the long intervals of terrestrial exposure during glacial periods. At the shelf edge the permafrost thins rapidly and also warms. This area has a very distinct morphology that we attribute to both the formation and degradation of ice bearing permafrost. Positive relief features include circular to oval shaped topographic mounds, up to 10 m high and ~50 m in diameter which occur at a density of ~6 per km2. Intermixed are circular topographic depressions up to 20 m deep. This topography was investigated using an autonomous underwater vehicle that provides 1 m horizontal resolution bathymetry and chirp profiles, a remotely operated vehicle to document seafloor textures, and sediment cores to sample pore waters. A consistent down-core freshening at rates of 14 to 96 mM Cl- per meter was found in these pore waters near the shelf edge. Downward extrapolation of these trends indicates water with ≤335 mM Cl- should occur at 2.3 to 22.4 m sub-seafloor depths within this shelf edge deformation band. Pore water with 335 mM Cl- or less freezes at -1.4°C. As bottom water temperatures in this area are persistently (<-1.4°C) cold and ground ice was observed in some core samples, we interpret the volume changes associated with mound formation are in part due to pore water freezing. Thermal models (Taylor et al., 2014) predict brackish water along the shelf edge may be sourced in relict permafrost melting under the adjacent continental shelf. Buoyant brackish water is hypothesized to migrate along the base of the relict permafrost, to emerge at the shelf edge and then refreeze when it encounters the colder seafloor. Expansion generated by the formation of ice-bearing permafrost generates the positive relief mounds and ridges. The associated negative relief features may be related to permafrost dynamics also. Permafrost dynamics may have geohazard implications that are unique to the

  9. Lessons Learned from Lessons Learned: The Fit between Online Education "Best Practices" and Small School Reality

    ERIC Educational Resources Information Center

    Lovvorn, Al S.; Barth, Michael M.; Morris, R. Franklin, Jr.; Timmerman, John E.

    2009-01-01

    Schools of all types and sizes are exploring the merits and facets of online learning approaches; but, the online delivery literature has focused on "best practices" generated primarily through the experiences of larger schools that are on the leading edge of this innovation. Small public schools, on the other hand, are faced with unique…

  10. Edge Response and NIIRS Estimates for Commercial Remote Sensing Satellites

    NASA Technical Reports Server (NTRS)

    Blonski, Slawomir; Ryan, Robert E.; Pagnutti, mary; Stanley, Thomas

    2006-01-01

    Spatial resolution of panchromatic imagery from commercial remote sensing satellites was characterized based on edge response measurements using edge targets and the tilted-edge technique. Relative Edge Response (RER) was estimated as a geometric mean of normalized edge response differences measured in two directions of image pixels at points distanced from the edge by -0.5 and 0.5 of ground sample distance. RER is one of the engineering parameters used in the General Image Quality Equation to provide predictions of imaging system performance expressed in terms of the National Imagery Interpretability Rating Scale (NIIRS). By assuming a plausible range of signal-to-noise ratio and assessing the effects of Modulation Transfer Function compensation, the NIIRS estimates were made and then compared with vendor-provided values and evaluations conducted by the National Geospatial-Intelligence Agency.

  11. Edge Minority Heating Experiment in Alcator C-Mod

    SciTech Connect

    S.J. Zweben; J.L. Terry; P. Bonoli; R. Budny; C.S. Chang; C. Fiore; G. Schilling; S. Wukitch; J. Hughes; Y. Lin; R. Perkins; M. Porkolab; the Alcator C-Mod Team

    2005-03-25

    An attempt was made to control global plasma confinement in the Alcator C-Mod tokamak by applying ion cyclotron resonance heating (ICRH) power to the plasma edge in order to deliberately create a minority ion tail loss. In theory, an edge fast ion loss could modify the edge electric field and so stabilize the edge turbulence, which might then reduce the H-mode power threshold or improve the H-mode barrier. However, the experimental result was that edge minority heating resulted in no improvement in the edge plasma parameters or global stored energy, at least at power levels of radio-frequency power is less than or equal to 5.5 MW. A preliminary analysis of these results is presented and some ideas for improvement are discussed.

  12. The role of edge-sensing in experiential psychotherapy.

    PubMed

    Glanzer, David; Early, Annmarie

    2012-01-01

    In experiential psychotherapy three modes of experiencing are managed in parallel--experiencing in the domain of explicit knowing, experiencing in implicit knowing, and experiencing in the zone of emergent formation where the other two meet. Gendlin (1996) argued that therapy is a "process that centrally involves experience before it becomes one of a set of defined 'packages' and again afterword when it dips back into the prepackaged zone at the edge of experiencing" (p. 4). In Gendlin's terms, the "edge" is where the prepackaged and packaged zones meet. Encounter at the edge, what we call edge sensing, is dwelling in the meeting point between what is known explicitly and what is known in an implicit bodied way. This encounter extends to dyadic encounter at the interpersonal edge in the therapeutic relationship. Edge sensing is an intrasubjective and intersubjective process crucial for the moving forward process of change.

  13. Efficient method of image edge detection based on FSVM

    NASA Astrophysics Data System (ADS)

    Cai, Aiping; Xiong, Xiaomei

    2013-07-01

    For efficient object cover edge detection in digital images, this paper studied traditional methods and algorithm based on SVM. It analyzed Canny edge detection algorithm existed some pseudo-edge and poor anti-noise capability. In order to provide a reliable edge extraction method, propose a new detection algorithm based on FSVM. Which contains several steps: first, trains classify sample and gives the different membership function to different samples. Then, a new training sample is formed by increase the punishment some wrong sub-sample, and use the new FSVM classification model for train and test them. Finally the edges are extracted of the object image by using the model. Experimental result shows that good edge detection image will be obtained and adding noise experiments results show that this method has good anti-noise.

  14. Atomic level spatial variations of energy states along graphene edges.

    PubMed

    Warner, Jamie H; Lin, Yung-Chang; He, Kuang; Koshino, Masanori; Suenaga, Kazu

    2014-11-12

    The local atomic bonding of carbon atoms around the edge of graphene is examined by aberration-corrected scanning transmission electron microscopy (STEM) combined with electron energy loss spectroscopy (EELS). High-resolution 2D maps of the EELS combined with atomic resolution annular dark field STEM images enables correlations between the carbon K-edge EELS and the atomic structure. We show that energy states of graphene edges vary across individual atoms along the edge according to their specific C-C bonding, as well as perpendicular to the edge. Unique spectroscopic peaks from the EELS are assigned to specific C atoms, which enables unambiguous spectroscopic fingerprint identification for the atomic structure of graphene edges with unprecedented detail.

  15. Bacterial foraging based edge detection for cell image segmentation.

    PubMed

    Pan, Yongsheng; Zhou, Tao; Xia, Yong

    2015-01-01

    Edge detection is the most popular and common choices for cell image segmentation, in which local searching strategies are commonly used. In spite of their computational efficiency, traditional edge detectors, however, may either produce discontinued edges or rely heavily on initializations. In this paper, we propose a bacterial foraging based edge detection (BFED) algorithm for cell image segmentation. We model the gradients of intensities as the nutrient concentration and propel bacteria to forage along nutrient-rich locations via mimicking the behavior of Escherichia coli, including the chemotaxis, swarming, reproduction, elimination and dispersal. As a nature-inspired evolutionary technique, this algorithm can identify the desired edges and mark them as the tracks of bacteria. We have evaluated the proposed algorithm against the Canny, SUSAN, Verma's and an active contour model (ACM) based edge detectors on both synthetic and real cell images. Our results suggest that the BFED algorithm can identify boundaries more effectively and provide more accurate cell image segmentation. PMID:26737139

  16. Western Australian School Students' Understanding of Biotechnology.

    ERIC Educational Resources Information Center

    Dawson, Vaille; Schibeci, Renato

    2003-01-01

    Surveys (n=1116) 15-year-old students from 11 Western Australian schools to determine their understanding of and attitude towards recent advances in modern biotechnology. Discusses reasons for students' over-estimation of the use of biotechnology in society. Provides a rationale for the inclusion of biotechnology, a cutting edge science, in the…

  17. Application technology of stacked film with highly controlled edge structure

    NASA Astrophysics Data System (ADS)

    Ichino, Katsunori; Tanouchi, Keiji; Iseki, Tomohiro; Ogata, Nobuhiro; Yamamoto, Taro; Yoshihara, Kosuke; Fujimoto, Akihiro

    2008-03-01

    On the device manufacturing, the film edge control around the wafer edge has been critical at the point of edge control of deposited film. So far, the film edge control is operated by the wafer edge exposure system and/or the edge beam remover. The immersion lithography which is applied to the device generation below 65 nm node requires more additional and severe items for film edge control. These typical requirements are position control of coating film and wafer bevel cleanness. For examples, top coat film is widely applied to the immersion lithography. But this topcoat film is easily peeled off, if top coat film edge should be directly located on the wafer substrate like Si wafer. Thus, the edge position of topcoat film must be controlled very carefully. And the particle or residues on the wafer bevel is thought to be one of the causes to generate immersion defect. Wafer bevel must be clean in order to reduce the immersion defect. Then we have developed novel application technology in order to solve these kinds of immersion defectivities. This new application technology is based on rinse solution technology and new hardware concept. This new application technology can control the edge position of coating film with high accuracy and can reduce the particle and residues. We show the edge position accuracy using our application technology and furthermore, the stability of edge position accuracy in case of multi-layered resist process. We also show the cleanness of the wafer bevel area at the same time. And we can achieve the immersion process with wide process latitude with innovative application technology.

  18. Leading-Edge "Pop-Up" Spoiler For Airfoil

    NASA Technical Reports Server (NTRS)

    Wilson, John C.; Lance, Michael B.

    1991-01-01

    New concept places spoiler in leading edge of airfoil, hinged along its trailing edge, so airflow helps to deploy it and force it against mechanical stop. Deployed "pop-up" spoiler quickly eliminates almost all aerodynamic lift of stabilator. Designed to be added to leading edge of existing stabilator, without major rework. Though initial application to be on helicopter stabilators, equally applicable to wings or winglike components.

  19. Integral edge seals for phosphoric acid fuel cells

    DOEpatents

    Granata, Jr., Samuel J.; Woodle, Boyd M.; Dunyak, Thomas J.

    1992-01-01

    A phosphoric acid fuel cell having integral edge seals formed by an elastomer permeating an outer peripheral band contiguous with the outer peripheral edges of the cathode and anode assemblies and the matrix to form an integral edge seal which is reliable, easy to manufacture and has creep characteristics similar to the anode, cathode and matrix assemblies inboard of the seals to assure good electrical contact throughout the life of the fuel cell.

  20. Edge removal balances preferential attachment and triad closing

    NASA Astrophysics Data System (ADS)

    Brot, Hilla; Honig, Michal; Muchnik, Lev; Goldenberg, Jacob; Louzoun, Yoram

    2013-10-01

    Most network formation analysis studies are centered on edge addition. However, edges in real world networks often have a rapid turnover with a large number of edges added and removed between each node addition or removal steps. In such a case, quasiequilibrium is obtained between edge addition and deletion. Edges have been shown to be added to nodes with a high degree and between pairs of nodes with a high number of common neighbors. If not balanced by a degree dependent edge removal, the preference for high degree nodes and node pairs with many common neighbors is expected to increase the average degree of high degree nodes and their clustering coefficient until very large cliques will be formed. Since such large cliques are not formed in real world networks, we conclude that the edge removal probability around high degree nodes and between node pairs with many common neighbors should be higher than around other nodes. We here show the existence of such a balancing mechanism through the relation between the future edge removal probability around nodes and their degree and a similar relation between the edge removal probability and the number of common neighbors of node pairs. In some networks, this preferential detachment process represents an explicit saturation process, and in others, it represents a random deletion process accompanied by a sublinear edge preferential attachment process. A more complex mechanism emerges in directed networks where the preferential detachment can be proportional to the in and out degrees of the nodes involved. In such networks, preferential detachment is stronger for the incoming edges than for the outgoing edges. We hypothesize multiple possible mechanisms that could explain this phenomenon.

  1. Edge Plasma Boundary Layer Generated By Kink Modes in Tokamaks

    SciTech Connect

    L.E. Zakharov

    2010-11-22

    This paper describes the structure of the electric current generated by external kink modes at the plasma edge using the ideally conducting plasma model. It is found that the edge current layer is created by both wall touching and free boundary kink modes. Near marginal stability, the total edge current has a universal expression as a result of partial compensation of the δ-functional surface current by the bulk current at the edge. The resolution of an apparent paradox with the pressure balance across the plasma boundary in the presence of the surface currents is provided.

  2. Majorana edge modes in Kitaev model on honeycomb lattice

    NASA Astrophysics Data System (ADS)

    Thakurathi, Manisha; Sengupta, Krishnendu; Sen, Diptiman

    2015-03-01

    We study the Majorana modes, both equilibrium and Floquet, which can appear at the edges of the Kitaev model on the honeycomb lattice. We first present the analytical solutions known for the equilibrium Majorana edge modes for both zigzag and armchair edges of a semi-infinite Kitaev model and chart the parameter regimes of the model in which they appear. We then examine how edge modes can be generated if the Kitaev coupling on the bonds perpendicular to the edge is varied periodically in time as periodic δ-function kicks. We derive a general condition for the appearance and disappearance of the Floquet edge modes as a function of the drive frequency for a generic d-dimensional integrable system. We confirm this general condition for the Kitaev model with a finite width by mapping it to a one-dimensional model. Our numerical and analytical study of this problem shows that Floquet Majorana modes can appear on some edges in the kicked system even when the corresponding equilibrium Hamiltonian has no Majorana mode solutions on those edges. We support our analytical studies by numerics for finite sized system which show that periodic kicks can generate modes at the edges and the corners of the lattice. We thank CSIR, India and DST, India for financial support.

  3. Simulations of Edge Current Driven Kink Modes with BOUT + + code

    NASA Astrophysics Data System (ADS)

    Li, G. Q.; Xu, X. Q.; Snyder, P. B.; Turnbull, A. D.; Xia, T. Y.; Ma, C. H.; Xi, P. W.

    2013-10-01

    Edge kink modes (or peeling modes) play a key role in the ELMs. The edge kink modes are driven by peak edge current, which comes from the bootstrap current. We calculated sequences of equilibria with different edge current using CORSICA by keeping total current and pressure profile fixed. Based on these equilibria, with the 3-field BOUT + + code, we calculated the MHD instabilities driven by edge current. For linear low-n ideal MHD modes, BOUT + + results agree with GATO results. With the edge current increasing, the dominant modes are changed from high-n ballooning modes to low-n kink modes. The edge current provides also stabilizing effects on high-n ballooning modes. Furthermore, for edge current scan without keeping total current fixed, the increasing edge current can stabilize the high-n ballooning modes and cannot drive kink modes. The diamagnetic effect can stabilize the high-n ballooning modes, but has no effect on the low-n kink modes. Also, the nonlinear behavior of kink modes is analyzed. Work supported by China MOST grant 2013GB111000 and by China NSF grant 10975161. Also performed for USDOE by LLNL under DE-AC52-07NA27344.

  4. Laminar Flow Control Leading Edge Systems in Simulated Airline Service

    NASA Technical Reports Server (NTRS)

    Wagner, R. D.; Maddalon, D. V.; Fisher, D. F.

    1988-01-01

    Achieving laminar flow on the wings of a commercial transport involves difficult problems associated with the wing leading edge. The NASA Leading Edge Flight Test Program has made major progress toward the solution of these problems. The effectiveness and practicality of candidate laminar flow leading edge systems were proven under representative airline service conditions. This was accomplished in a series of simulated airline service flights by modifying a JetStar aircraft with laminar flow leading edge systems and operating it out of three commercial airports in the United States. The aircraft was operated as an airliner would under actual air traffic conditions, in bad weather, and in insect infested environments.

  5. Line Edge Detection and Characterization in SEM Images using Wavelets

    SciTech Connect

    Sun, W; Romagnoli, J A; Tringe, J W; L?tant, S E; Stroeve, P; Palazoglu, A

    2008-10-07

    Edge characterization has become increasingly important in nanotechnology due to the growing demand for precise nanoscale structure fabrication and assembly. Edge detection is often performed by thresholding the spatial information of a top-down image obtained by Scanning Electron Microscopy (SEM) or other surface characterization techniques. Results are highly dependent on an arbitrary threshold value, which makes it difficult to reveal the nature of the real surface and to compare results among images. In this paper, we present an alternative edge boundary detection technique based on the wavelet framework. Our results indicate that the method facilitates nano-scale edge detection and characterization, by providing a systematic threshold determination step.

  6. Development of X-43A Mach 10 Leading Edges

    NASA Technical Reports Server (NTRS)

    Ohlhorst, Craig W.; Glass, David E.; Bruce, Walter E., III; Lindell, Michael C.; Vaughn, Wallace L.; Dirling, R. B., Jr.; Hogenson, P. A.; Nichols, J. M.; Risner, N. W.; Thompson, D. R.

    2005-01-01

    The nose leading edge of the Hyper-X Mach 10 vehicle was orginally anticipated to reach temperatures near 4000 F at the leading-edge stagnation line. A SiC coated carbon/carbon (C/C) leading-edge material will not survive that extreme temperature for even a short duration single flight. To identify a suitable leading edge for the Mach 10 vehicle, arc-jet testing was performed on thirteen leading-edge segments fabricated from different material systems to evaluate their performance in a simulated flight environment. Hf, Zr, Si, and Ir based materials, in most cases as a coating on C/C, were included in the evaluation. Afterwards, MER, Tucson, AZ was selected as the supplier of the flight vehicle leading edges. The nose and the vertical and horizontal tail leading edges were fabricated out of a 3:1 biased high thermal conductivity C/C. The leading edges were coated with a three layer coating comprised of a SiC conversion of the top surface of the C/C, followed by a chemical vapor deposited layer of SiC, followed by a thin chemical vapor deposited layer of HfC. This paper will describe the fabrication of the Mach 10 C/C leading edges and the testing performed to validate performance.

  7. Evidence for edge effects on multiple levels in tallgrass prairie

    USGS Publications Warehouse

    Winter, M.; Johnson, D.H.; Faaborg, J.

    2000-01-01

    We tested how edges affect nest survival and predator distribution in a native tallgrass prairie system in southwestern Missouri using artificial nests, natural nests of Dickcissels (Spiza americana) and Henslow's Sparrows (Ammodramus henslowii), and mammal track stations. Survival of artificial nests was lower within 30 m of forest edge. Nesting success of Dickcissels and Henslow's Sparrows was lower within 50 m to a shrubby edge than at greater distances, whereas fates of nests were not related to distances to roads, agricultural fields, or forests. Evidence from clay eggs placed in artificial nests indicated that mid-sized carnivores were the major predators within 30 m of forest edges. Furthermore, mid-sized carnivores visited track stations most frequently within 50 m of forest edges. Because proximity of woody habitat explained more variation in nest survival and mammal activity than did fragment size, it appears that edge effects were more pronounced than area effects. Edge effects appeared to be caused mainly by greater exposure of nests to midsized carnivores. We argue that, based on edge avoidance behavior, 'grassland-interior' species such as the Henslow's Sparrow respond to edge effects mainly by a decrease in density, whereas habitat generalists such as the Dickcissel are affected mainly by a decrease in nesting success.

  8. Spiraling Edge: Fast Surface Reconstruction from Partially Organized Sample Points

    SciTech Connect

    Angel, Edward; Crossno, Patricia

    1999-07-12

    Many applications produce three-dimensional points that must be further processed to generate a surface. Surface reconstruction algorithms that start with a set of unorganized points are extremely time-consuming. Sometimes, however, points are generated such that there is additional information available to the reconstruction algorithm. We present Spiraling Edge, a specialized algorithm for surface reconstruction that is three orders of magnitude faster than algorithms for the general case. In addition to sample point locations, our algorithm starts with normal information and knowledge of each point's neighbors. Our algorithm produces a localized approximation to the surface by creating a star-shaped triangulation between a point and a subset of its nearest neighbors. This surface patch is extended by locally triangulating each of the points along the edge of the patch. As each edge point is triangulated, it is removed from the edge and new edge points along the patch's edge are inserted in its place. The updated edge spirals out over the surface until the edge encounters a surface boundary and stops growing in that direction, or until the edge reduces to a small hole that is filled by the final triangle.

  9. Cutting Edge Geometry Effect on Plastic Deformation of Titanium Alloy

    NASA Astrophysics Data System (ADS)

    Korovin, G. I.; Filippov, A. V.; Proskokov, A. V.; Gorbatenko, V. V.

    2016-04-01

    The paper presents experimental studies of OT4 titanium alloy machining with cutting edges of various geometry parameters. Experiments were performed at a low speed by the scheme of free cutting. Intensity of plastic shear strain was set for defining of cutting edge geometry effect on machining. Images of chip formed are shown. Estimation of strain magnitude was accomplished with digital image correlation method. Effect of rake angle and cutting edge angle has been studied. Depth of deformed layer and the area of the plastic strain is determine. Results showed that increasing the angle of the cutting edge inclination results in a change the mechanism of chip formation.

  10. Method for edge detection in images using fuzzy relation

    NASA Astrophysics Data System (ADS)

    Nieradka, Grzegorz

    2008-01-01

    Edge detection is one of the most important tasks in machine vision and image processing. The paper presents novel approach to construction of algorithm for detection edges in images. In order to solve the problem the concepts of the fuzzy similarity relation and homogeneity region were exploited. The results of application of the proposed edge calculation method are presented in this paper. Additionally, this paper presents an interesting artistic effect obtained by application of the image processing method based on such the detection of edges. Possible artistic effects of application of this algorithm are exemplified.

  11. Edge Turbulence Velocity Changes with Lithium Coating on NSTX

    SciTech Connect

    Cao, A.; Zweben, S. J.; Stotler, D. P.; Bell, M.; Diallo, A.; Kaye, S. M.; LeBlanc, B.

    2012-08-10

    Lithium coating improves energy confinement and eliminates edge localized modes in NSTX, but the mechanism of this improvement is not yet well understood. We used the gas-puff-imaging (GPI) diagnostic on NSTX to measure the changes in edge turbulence which occurred during a scan with variable lithium wall coating, in order to help understand the reason for the confinement improvement with lithium. There was a small increase in the edge turbulence poloidal velocity and a decrease in the poloidal velocity fluctuation level with increased lithium. The possible effect of varying edge neutral density on turbulence damping was evaluated for these cases in NSTX. __________________________________________________

  12. Evolution of edge pedestal transport between edge-localized modes in DIII-D

    SciTech Connect

    Floyd, J.-P.; Stacey, W. M.; Mellard, S. C.; Groebner, R. J.

    2015-02-15

    Evolution of measured profiles of densities, temperatures, and velocities in the edge pedestal region between successive ELM (edge-localized mode) events are analyzed and interpreted in terms of the constraints imposed by particle, momentum and energy balance in order to gain insights regarding the underlying evolution of transport processes in the edge pedestal between ELMs in a series of DIII-D [J. Luxon, Nucl. Fusion 42, 614 (2002)] discharges. The data from successive inter-ELM periods during an otherwise steady-state phase of the discharges were combined into a composite inter-ELM period for the purpose of increasing the number of data points in the analysis. Variation of diffusive and non-diffusive (pinch) particle, momentum, and energy transport over the inter-ELM period are interpreted using the GTEDGE code for discharges with plasma currents from 0.5 to 1.5 MA and inter-ELM periods from 50 to 220 ms. Diffusive transport is dominant for ρ < 0.925, while non-diffusive and diffusive transport are very large and nearly balancing in the sharp gradient region 0.925 < ρ < 1.0. During the inter-ELM period, diffusive transport increases slightly more than non-diffusive transport, increasing total outward transport. Both diffusive and non-diffusive transport have a strong inverse correlation with plasma current.

  13. Edge contact dependent spin transport for n-type doping zigzag-graphene with asymmetric edge hydrogenation.

    PubMed

    Deng, Xiaoqing; Zhang, Zhenhua; Tang, Guiping; Fan, Zhiqiang; Zhu, Huali; Yang, Changhu

    2014-01-01

    Spin transport features of the n-type doping zigzag graphene nanoribbons (ZGNRs) with an edge contact are investigated by first principle methods, where ZGNRs are C-H2 bonded at one edge while C-H bonded at the other to form an asymmetric edge hydrogenation. The results show that a perfect spin filtering effect (100%) in such ZGNR nanojunctions can be achieved in a very large bias region for the unchanged spin states regardless of bias polarities, and the nanojunction with a contact of two C-H2 bonded edges has larger spin polarized current than that with a contact of two C-H bonded edges. The transmission pathways and the projected density of states (PDOS) demonstrate that the edge of C-H2 bonds play a crucial role for the spin magnetism and spin-dependent transport properties. Moreover, the negative differential resistance (NDR) effect is also observed in the spin-polarized current.

  14. Edge contact dependent spin transport for n-type doping zigzag-graphene with asymmetric edge hydrogenation

    PubMed Central

    Deng, Xiaoqing; Zhang, Zhenhua; Tang, Guiping; Fan, Zhiqiang; Zhu, Huali; Yang, Changhu

    2014-01-01

    Spin transport features of the n-type doping zigzag graphene nanoribbons (ZGNRs) with an edge contact are investigated by first principle methods, where ZGNRs are C–H2 bonded at one edge while C–H bonded at the other to form an asymmetric edge hydrogenation. The results show that a perfect spin filtering effect (100%) in such ZGNR nanojunctions can be achieved in a very large bias region for the unchanged spin states regardless of bias polarities, and the nanojunction with a contact of two C–H2 bonded edges has larger spin polarized current than that with a contact of two C–H bonded edges. The transmission pathways and the projected density of states (PDOS) demonstrate that the edge of C-H2 bonds play a crucial role for the spin magnetism and spin-dependent transport properties. Moreover, the negative differential resistance (NDR) effect is also observed in the spin-polarized current. PMID:24509476

  15. [Microbes on the edge of global biosphere].

    PubMed

    Naganuma, T

    2000-12-01

    The search for life on the edge of global biosphere is a frontier to bridge conventional bio/ecology and exo/astrobiology. This communication reviews the foci of microbiological studies on the inhabitants of the selected "edges", i.e., deep-sea, deep subsurface and Antarctic habitats. The deep-sea is characterized as the no-light (non-photosynthetic) habitat, and the primary production is mostly due to the chemosynthetic autotrophy at the hydrothermal vents and methane-rich seeps. Formation of the chemosynthesis-dependent animal communities in the deep leads to the idea that such communities may be found in "ocean" of the Jovian satellite, Europa. The oxygen minimal layer (OML) in mid-water provides another field of deep-sea research. Modern OML is a relatively thin layer, found between the water depth of 200 and 1000 m, but was much thicker during the periods of oceanic anoxia events (OAEs) in the past. The history of oceanic biosphere is regarded as the cycle of OAE and non-OAE periods, and the remnants of the past OAEs may be seen in the modem OML. Anoxic (no-O2) condition is also characteristic of deep subsurface biosphere. Microorganisms in deep subsurface biosphere exploit every available oxidant, or terminal electron acceptor (TEA), for anaerobic respiration. Sulfate, nitrate, iron (III) and CO2 are the representative TEAs in the deep subsurface. Subsurface of hydrothermal vents, or sub-vent biosphere, may house brine (high salt) habitats and halophilic microorganisms. Some sub-vent halophiles were phylogenetically closely similar to the ones found in the Antarctic habitats which are extremely dry by the liophilizing climate. Below the 3000-4000 m-thick glacier on Antarctica, there have been >70 lakes with liquid water located. One of such sub-glacial lakes, Lake Vostok, has been a target of "life in extreme environments" and is about to be drill-penetrated for microbiological studies. These 'microbiological platforms' will provide new knowledge about the

  16. [Microbes on the edge of global biosphere].

    PubMed

    Naganuma, T

    2000-12-01

    The search for life on the edge of global biosphere is a frontier to bridge conventional bio/ecology and exo/astrobiology. This communication reviews the foci of microbiological studies on the inhabitants of the selected "edges", i.e., deep-sea, deep subsurface and Antarctic habitats. The deep-sea is characterized as the no-light (non-photosynthetic) habitat, and the primary production is mostly due to the chemosynthetic autotrophy at the hydrothermal vents and methane-rich seeps. Formation of the chemosynthesis-dependent animal communities in the deep leads to the idea that such communities may be found in "ocean" of the Jovian satellite, Europa. The oxygen minimal layer (OML) in mid-water provides another field of deep-sea research. Modern OML is a relatively thin layer, found between the water depth of 200 and 1000 m, but was much thicker during the periods of oceanic anoxia events (OAEs) in the past. The history of oceanic biosphere is regarded as the cycle of OAE and non-OAE periods, and the remnants of the past OAEs may be seen in the modem OML. Anoxic (no-O2) condition is also characteristic of deep subsurface biosphere. Microorganisms in deep subsurface biosphere exploit every available oxidant, or terminal electron acceptor (TEA), for anaerobic respiration. Sulfate, nitrate, iron (III) and CO2 are the representative TEAs in the deep subsurface. Subsurface of hydrothermal vents, or sub-vent biosphere, may house brine (high salt) habitats and halophilic microorganisms. Some sub-vent halophiles were phylogenetically closely similar to the ones found in the Antarctic habitats which are extremely dry by the liophilizing climate. Below the 3000-4000 m-thick glacier on Antarctica, there have been >70 lakes with liquid water located. One of such sub-glacial lakes, Lake Vostok, has been a target of "life in extreme environments" and is about to be drill-penetrated for microbiological studies. These 'microbiological platforms' will provide new knowledge about the

  17. Wisps in the outer edge of the Keeler Gap

    NASA Astrophysics Data System (ADS)

    Tiscareno, Matthew S.; Arnault, Ethan G.

    2015-11-01

    Superposed upon the relatively smooth outer edge of the Keeler Gap are a system of "wisps," which appear to be ring material protruding inward into the gap, usually with a sharp trailing edge and a smooth gradation back to the background edge location on the leading side (Porco et al. 2005, Science). The radial amplitude of wisps is usually 0.5 to 1 km, and their azimuthal extent is approximately a degree of longitude (~2400 km). Wisps are likely caused by an interplay between Daphnis (and perhaps other moons) and embedded moonlets within the ring, though the details remain unclear.Aside from the wisps, the Keeler Gap outer edge is the only one of the five sharp edges in the outer part of Saturn's A ring that is reasonably smooth in appearance (Tiscareno et al. 2005, DPS), with occultations indicating residuals less than 1 km upon a possibly non-zero eccentricity (R.G. French, personal communication, 2014). The other four (the inner and outer edges of the Encke Gap, the inner edge of the Keeler Gap, and the outer edge of the A ring itself) are characterized by wavy structure at moderate to high spatial frequencies, with amplitudes ranging from 2 to 30 km (Tiscareno et al. 2005, DPS).We will present a catalogue of wisp detections in Cassini images. We carry out repeated gaussian fits of the radial edge location in order to characterize edge structure and visually scan those fitted edges in order to detect wisps. With extensive coverage in longitude and in time, we will report on how wisps evolve and move, both within an orbit period and on longer timescales. We will also report on the frequency and interpretation of wisps that deviate from the standard morphology. We will discuss the implications of our results for the origin and nature of wisps, and for the larger picture of how masses interact within Saturn's rings.

  18. Nanographene and graphene edges: electronic structure and nanofabrication.

    PubMed

    Fujii, Shintaro; Enoki, Toshiaki

    2013-10-15

    Graphene can be referred to as an infinite polycyclic aromatic hydrocarbon (PAH) consisting of an infinite number of benzene rings fused together. However, at the nanoscale, nanographene's properties lie in between those of bulk graphene and large PAH molecules, and its electronic properties depend on the influence of the edges, which disrupt the infinite π-electron system. The resulting modulation of the electronic states depends on whether the nanographene edge is the armchair or zigzag type, corresponding to the two fundamental crystal axes. In this Account, we report the results of fabricating both types of edges in the nanographene system and characterizing their electronic properties using a scanning probe microscope. We first introduce the theoretical background to understand the two types of finite size effects on the electronic states of nanographene (i) the standing wave state and (ii) the edge state which correspond to the armchair and zigzag edges, respectively. Most importantly, characterizing the standing wave and edge states could play a crucial role in understanding the chemical reactivity, thermodynamic stability and magnetism of nanosized graphene--important knowledge in the design and realization of promising functionalized nanocarbon materials. In the second part, we present scanning probe microscopic characterization of both edge types to experimentally characterize the two electronic states. As predicted, we find the armchair-edged nanographene to have an energetically stable electronic pattern. The zigzag-edged nanographene shows a nonbonding (π radical) pattern, which is the source of the material's electronic and magnetic properties and its chemical activity. Precise control of the edge geometry is a practical requirement to control the electronic structure. We show that we can fabricate the energetically unstable zigzag edges using scanning probe manipulation techniques, and we discuss challenges in using these techniques for that

  19. Edge-preserving metal artifact reduction

    NASA Astrophysics Data System (ADS)

    Meyer, Esther; Raupach, Rainer; Lell, Michael; Schmidt, Bernhard; Kachelriess, Marc

    2012-03-01

    Metal implants in the field of measurement lead to strong artifacts in CT images and reduce the image quality and the diagnostic value severely. We introduce frequency split metal artifact reduction (FSMAR), a conceptually new MAR method which is designed to reduce metal artifacts and preserve details and edges of structures even close to metal implants. There are many MAR methods which simply replace unreliable parts of the projection data by inpainting. FSMAR is a combination of an inpainting-based MAR method with a frequency split approach. Normalized metal artifact reduction (NMAR) is chosen as the inpainting-based MAR method in this work. The high frequencies of the original image, where all rawdata were used for the reconstruction, are combined with an NMAR-corrected image. NMAR uses a normalization step to reduce metal artifacts without introducing severe new artifacts. Algorithms using a frequency split were already used in CT for example to reduce cone-beam artifacts. FSMAR is tested for patient datasets with different metal implants. The study includes patients with hip prostheses, a neuro coil, and a spine fixation. All datasets were scanned with modern clinical dual source CT scanners. In contrast to other MAR methods, FSMAR yields images without the usual blurring close to metal implants.

  20. Hermetic edge sealing of photovoltaic modules

    NASA Technical Reports Server (NTRS)

    Nowlan, M. J.

    1983-01-01

    The feasibility of using an electrostatic bonding (ESB) and ultrasonic welding process to produce hermetic edge seals on terrestrial solar cell modules was investigated. The fabrication sequence is to attach an aluminum foil "gasket' to the perimeter of a glass sheet. A cell circuit is next encapsulated inside the gasket, and its aluminum foil back cover is seam welded ultrasonically to the gasket. An ESB process for sealing aluminum to glass was developed in an ambient air atmosphere, which eliminates the requirement for a vacuum or pressure vessel. An ultrasonic seam welding process was also developed which did not degrade the quality of the ESB seal. Good quality welds with minimal deformation were produced. The effectiveness of the above described sealing techniques was tested by constructing 400 sq cm (8 x 8 s64 sq in) sample modules, and then subjecting them to nondestructive fine and gross leak tests. The gross leak tests identified several different causes of leaks which were then eliminated by modifying the assembly process.

  1. Computational investigation of miniature trailing edge effectors

    NASA Astrophysics Data System (ADS)

    Lee, Hak-Tae

    Miniature trailing edge effectors (MiTEs) are small flaps (typically 1% to 5% chord) actuated with deflection angles of up to 90 degrees. The small size, combined with little required power and good control authority, enables the device to be used for high bandwidth control as well as conventional attitude control. However, some of the aerodynamic characteristics of these devices are complex and poorly understood. This research investigated the aerodynamics of MiTEs using incompressible Navier-Stokes flow solvers, INS2D and INS3D. To understand the flow structure and establish a parametric database, two dimensional steady-state computations were performed for MiTEs with various geometries and flow conditions. Time accurate computations were used to resolve the unsteady characteristics including transient response and vortex shedding phenomena. The frequency response was studied to fully identify the dynamics of MiTEs. Three dimensional computations show the change in control effectiveness with respect to the spanwise length of MiTEs as well as the spanwise lift distribution induced by these devices. Based on the CFD results, an approximate vortex panel model was developed for design purposes that reproduces the key characteristics of MiTEs. Two application areas for MiTEs were explored. Flutter suppression was demonstrated by combining a finite element structural model with the vortex panel model. The application of MiTEs to augment maximum lift and improve the post stall behavior of an airfoil was also investigated.

  2. At the cutting edge of VOC destruction

    SciTech Connect

    1995-05-01

    Of the 189 substances named as Hazardous Air Pollutants under Title 3 of the 1990 Clean Air Act Amendments, approximately 160 are classified as volatile organic compounds (VOCs). Stationary sources producing as little as 10 tons per year of any listed substance or 25 tons per year of any combination of listed substances are subject to Title 5 permitting regulations. This shifts the focus from larger installations and means that cost-effective VOC control must be made available for sources producing flows under 5,000 cfm at concentrations less than 500 ppm. And, the VOCs must be controlled without producing high NO{sub x} emissions. In response to this need, Alzeta Corp., with support from the Gas Research Institute (GRI), has developed and is testing the Edge Plus+ family of VOC abatement devices. The systems are specially designed for low flows and low concentrations and can be configured to destroy virtually all types of VOCS. The gas-fired systems use thermal destruction units that provide greater than 99.99% destruction and removal efficiency (DRE) over a wide range of concentrations and operating conditions, thus assuring compliance with all existing and proposed regulations. They also produce less than 10 ppm NO{sub x} and CO (less than 0.01 lbs./MMbtu input).

  3. The permeability of the Antarctic vortex edge

    NASA Technical Reports Server (NTRS)

    Chen, Ping

    1994-01-01

    Mixing and cross-vortex mass transport along isentropic surfaces in the lower stratosphere are investigated with a 'contour advection' technique and a semi-Lagrangian transport model for the Antarctic winter of 1993 using analyzed winds from the United Kingdom Meteorological Office data assimilation system. Results from the 'contour advection' technique show that at the vortex edge there exists a potential vorticity (PV) contour that has the smallest lengthening rate. This PV contour is referred to as the 'line of separation' because it essentially separates the inner and outer vortex. The average e-folding time for the lengthening of the 'line of separation' increases monotonically with altitude, ranging from about 7 days on the 350 K isentropic surface to about 105 days on the 500 K isentropic surface. The results also suggest the existence of a transition layer around the 400 K isentropic surface, above which the vortex is nearly completely isolated from the midlatitudes and below which the vortex is less isolated. Results from a semi-Lagrangian transport model with an idealized tracer initially inside the inner vortex show that at 425 K and above virtually no tracer is transported out of the vortex during a 40-day integration starting from July 21, 1993. At 400 K and below a small amount of the tracer is transported out of the vortex while the bulk of the tracer remains confined within the inner vortex.

  4. Textbook Multigrid Efficiency for Leading Edge Stagnation

    NASA Technical Reports Server (NTRS)

    Diskin, Boris; Thomas, James L.; Mineck, Raymond E.

    2004-01-01

    A multigrid solver is defined as having textbook multigrid efficiency (TME) if the solutions to the governing system of equations are attained in a computational work which is a small (less than 10) multiple of the operation count in evaluating the discrete residuals. TME in solving the incompressible inviscid fluid equations is demonstrated for leading- edge stagnation flows. The contributions of this paper include (1) a special formulation of the boundary conditions near stagnation allowing convergence of the Newton iterations on coarse grids, (2) the boundary relaxation technique to facilitate relaxation and residual restriction near the boundaries, (3) a modified relaxation scheme to prevent initial error amplification, and (4) new general analysis techniques for multigrid solvers. Convergence of algebraic errors below the level of discretization errors is attained by a full multigrid (FMG) solver with one full approximation scheme (F.4S) cycle per grid. Asymptotic convergence rates of the F.4S cycles for the full system of flow equations are very fast, approaching those for scalar elliptic equations.

  5. Textbook Multigrid Efficiency for Leading Edge Stagnation

    NASA Technical Reports Server (NTRS)

    Diskin, Boris; Thomas, James L.; Mineck, Raymond E.

    2004-01-01

    A multigrid solver is defined as having textbook multigrid efficiency (TME) if the solutions to the governing system of equations are attained in a computational work which is a small (less than 10) multiple of the operation count in evaluating the discrete residuals. TME in solving the incompressible inviscid fluid equations is demonstrated for leading-edge stagnation flows. The contributions of this paper include (1) a special formulation of the boundary conditions near stagnation allowing convergence of the Newton iterations on coarse grids, (2) the boundary relaxation technique to facilitate relaxation and residual restriction near the boundaries, (3) a modified relaxation scheme to prevent initial error amplification, and (4) new general analysis techniques for multigrid solvers. Convergence of algebraic errors below the level of discretization errors is attained by a full multigrid (FMG) solver with one full approximation scheme (FAS) cycle per grid. Asymptotic convergence rates of the FAS cycles for the full system of flow equations are very fast, approaching those for scalar elliptic equations.

  6. Tempest Neoclassical Simulation of Fusion Edge Plasmas

    NASA Astrophysics Data System (ADS)

    Xu, X. Q.; Xiong, Z.; Cohen, B. I.; Cohen, R. H.; Dorr, M.; Hittinger, J.; Kerbel, G. D.; Nevins, W. M.; Rognlien, T. D.

    2006-04-01

    We are developing a continuum gyrokinetic full-F code, TEMPEST, to simulate edge plasmas. The geometry is that of a fully diverted tokamak and so includes boundary conditions for both closed magnetic flux surfaces and open field lines. The code, presently 4-dimensional (2D2V), includes kinetic ions and electrons, a gyrokinetic Poisson solver for electric field, and the nonlinear Fokker-Planck collision operator. Here we present the simulation results of neoclassical transport with Boltzmann electrons. In a large aspect ratio circular geometry, excellent agreement is found for neoclassical equilibrium with parallel flows in the banana regime without a temperature gradient. In divertor geometry, it is found that the endloss of particles and energy induces pedestal-like density and temperature profiles inside the magnetic separatrix and parallel flow stronger than the neoclassical predictions in the SOL. The impact of the X-point divertor geometry on the self-consistent electric field and geo-acoustic oscillations will be reported. We will also discuss the status of extending TEMPEST into a 5-D code.

  7. Agile robotic edge finishing system research

    SciTech Connect

    Powell, M.A.

    1995-07-01

    This paper describes a new project undertaken by Sandia National Laboratories to develop an agile, automated, high-precision edge finishing system. The project has a two-year duration and was initiated in October, 1994. This project involves re-designing and adding additional capabilities to an existing finishing workcell at Sandia; and developing intelligent methods for automating process definition and for controlling finishing processes. The resulting system will serve as a prototype for systems that will be deployed into highly flexible automated production lines. The production systems will be used to produce a wide variety of products with limited production quantities and quick turnaround requirements. The prototype system is designed to allow programming, process definition, fixture re-configuration, and process verification to be performed off-line for new products. CAD/CAM (Computer Aided Design/Computer Aided Manufacturing) models of the part will be used to assist with the automated process development and process control tasks. To achieve Sandia`s performance goals, the system will be employ advanced path planning, burr prediction expert systems, automated process definition, statistical process models in a process database, and a two-level control scheme using hybrid position-force control and fuzzy logic control. In this paper, we discuss the progress and the planned system development under this project.

  8. Recent progress in the tokamak edge modeling

    NASA Astrophysics Data System (ADS)

    Petravic, M.; Heifetz, D.; Heifetz, S.; Post, D.

    1984-12-01

    Tokamak edge modeling, with a particular emphasis on divertors, was reviewed in detail in 1982. At that time the emphasis was on the qualitative behavior of the scrape-off plasma and the atomic processes involved in the neutral-plasma interaction. While no detailed comparisons with the experiments were available, the data nevertheless showed all the basic features of the cool high-density regime predicted by the models. The two most important modeling developments of 1983 were the introduction of accurate magnetic geometries and the inclusion of impurity transport in the plasma equations. This made possible detailed comparisons with the PDX and ASDEX experiments which on the one hand showed remarkable agreement while on the other hand pointed to new areas of uncertainty, i.e., the plasma-wall and neutral-wall interactions. In another development, the scrape-off models are beginning to be linked to the main plasma transport in order to provide better boundary conditions for the main plasma models, and in particular to model limiters. The fully two-dimensional plasma flow models should be particularly useful in this area.

  9. Continuum Edge Gyrokinetic Theory and Simulations

    SciTech Connect

    Xu, X Q; Xiong, Z; Dorr, M R; Hittinger, J A; Bodi, K; Candy, J; Cohen, B I; Cohen, R H; Colella, P; Kerbel, G D; Krasheninnikov, S; Nevins, W M; Qin, H; Rognlien, T D; Snyder, P B; Umansky, M V

    2007-01-09

    The following results are presented from the development and application of TEMPEST, a fully nonlinear (full-f) five dimensional (3d2v) gyrokinetic continuum edge-plasma code. (1) As a test of the interaction of collisions and parallel streaming, TEMPEST is compared with published analytic and numerical results for endloss of particles confined by combined electrostatic and magnetic wells. Good agreement is found over a wide range of collisionality, confining potential, and mirror ratio; and the required velocity space resolution is modest. (2) In a large-aspect-ratio circular geometry, excellent agreement is found for a neoclassical equilibrium with parallel ion flow in the banana regime with zero temperature gradient and radial electric field. (3) The four-dimensional (2d2v) version of the code produces the first self-consistent simulation results of collisionless damping of geodesic acoustic modes and zonal flow (Rosenbluth-Hinton residual) with Boltzmann electrons using a full-f code. The electric field is also found to agree with the standard neoclassical expression for steep density and ion temperature gradients in the banana regime. In divertor geometry, it is found that the endloss of particles and energy induces parallel flow stronger than the core neoclassical predictions in the SOL. (5) Our 5D gyrokinetic formulation yields a set of nonlinear electrostatic gyrokinetic equations that are for both neoclassical and turbulence simulations.

  10. Edge gyrokinetic theory and continuum simulations

    NASA Astrophysics Data System (ADS)

    Xu, X. Q.; Xiong, Z.; Dorr, M. R.; Hittinger, J. A.; Bodi, K.; Candy, J.; Cohen, B. I.; Cohen, R. H.; Colella, P.; Kerbel, G. D.; Krasheninnikov, S.; Nevins, W. M.; Qin, H.; Rognlien, T. D.; Snyder, P. B.; Umansky, M. V.

    2007-08-01

    The following results are presented from the development and application of TEMPEST, a fully nonlinear (full-f) five-dimensional (3d2v) gyrokinetic continuum edge-plasma code. (1) As a test of the interaction of collisions and parallel streaming, TEMPEST is compared with published analytic and numerical results for endloss of particles confined by combined electrostatic and magnetic wells. Good agreement is found over a wide range of collisionality, confining potential and mirror ratio, and the required velocity space resolution is modest. (2) In a large-aspect-ratio circular geometry, excellent agreement is found for a neoclassical equilibrium with parallel ion flow in the banana regime with zero temperature gradient and radial electric field. (3) The four-dimensional (2d2v) version of the code produces the first self-consistent simulation results of collisionless damping of geodesic acoustic modes and zonal flow (Rosenbluth-Hinton residual) with Boltzmann electrons using a full-f code. The electric field is also found to agree with the standard neoclassical expression for steep density and ion temperature gradients in the plateau regime. In divertor geometry, it is found that the endloss of particles and energy induces parallel flow stronger than the core neoclassical predictions in the SOL.

  11. Saturday School

    ERIC Educational Resources Information Center

    Pratt, Allen

    2011-01-01

    When the author became principal at South Pittsburg High School in the rural southeast corner of Tennessee, he noticed that the school had a serious problem with students arriving late to school in the morning and late to classes during the school day. When this issue was discussed, it was decided that there was a need to initiate a Saturday…

  12. Good Schools.

    ERIC Educational Resources Information Center

    Schoenheimer, Henry P.

    This book contains seventeen thumb-nail sketches of schools in Europe, the United States, Asia, Britain, and Australia, as they appeared in the eye of the author as a professional educator and a journalist while travelling around the world. The author considers the schools described to be good schools, and not necessarily the 17 best schools in…

  13. School Violence.

    ERIC Educational Resources Information Center

    Hinkle, William G., Ed.; Henry, Stuart, Ed.

    2000-01-01

    This volume presents papers from a 1998 conference on school violence in Valparaiso, Indiana. The papers include: "What is School Violence? An Integrated Definition" (Stuart Henry); "Violence in Schools: Rage against a Broken World" (J. Scott Staples); "Listening to What the Streets Say: Vengeance as Ideology?" (Ralph Cintron); "School Violence:…

  14. 12 CFR 211.5 - Edge and agreement corporations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... notice. The Board shall publish in the Federal Register notice of any proposal to organize an Edge...) Factors considered by Board. The factors considered by the Board in acting on a proposal to organize an... inconsistent with the international and foreign business purposes for which Edge corporations are...

  15. Laboratory and field investigations of marsh edge erosion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter presents the laboratory experiments and field observations of marsh edge erosion. The marsh retreat rate in a field study site in Terrebonne Bay, Louisiana, was measured using GPS systems and aerial photographs. The wave environment was also measured in order to correlate the marsh edge...

  16. Toward edge minability for role mining in bipartite networks

    NASA Astrophysics Data System (ADS)

    Dong, Lijun; Wang, Yi; Liu, Ran; Pi, Benjie; Wu, Liuyi

    2016-11-01

    Bipartite network models have been extensively used in information security to automatically generate role-based access control (RBAC) from dataset. This process is called role mining. However, not all the topologies of bipartite networks are suitable for role mining; some edges may even reduce the quality of role mining. This causes unnecessary time consumption as role mining is NP-hard. Therefore, to promote the quality of role mining results, the capability that an edge composes roles with other edges, called the minability of edge, needs to be identified. We tackle the problem from an angle of edge importance in complex networks; that is an edge easily covered by roles is considered to be more important. Based on this idea, the k-shell decomposition of complex networks is extended to reveal the different minability of edges. By this way, a bipartite network can be quickly purified by excluding the low-minability edges from role mining, and thus the quality of role mining can be effectively improved. Extensive experiments via the real-world datasets are conducted to confirm the above claims.

  17. Processing of Superconductor-Normal-Superconductor Josephson Edge Junctions

    NASA Technical Reports Server (NTRS)

    Kleinsasser, A. W.; Barner, J. B.

    1997-01-01

    The electrical behavior of epitaxial superconductor-normal-superconductor (SNS) Josephson edge junctions is strongly affected by processing conditions. Ex-situ processes, utilizing photoresist and polyimide/photoresist mask layers, are employed for ion milling edges for junctions with Yttrium-Barium-Copper-Oxide (YBCO) electrodes and primarily Co-doped YBCO interlayers.

  18. Edge magnetization in Bernal-stacked trilayer zigzag graphene nanoribbons

    NASA Astrophysics Data System (ADS)

    Pérez, Juan Antonio Casao

    2016-06-01

    We have used a tight-binding Hamiltonian of an ABA-stacked trilayer zigzag graphene nanoribbon with β-alignment edges to study the edge magnetizations. Our model includes the effect of the intralayer next-nearest-neighbor hopping, the interlayer hopping responsible for the trigonal warping and the interaction between electrons, which is considered by a single band Hubbard model in the mean field approximation. Firstly, in the neutral system we analyzed the two magnetic states in which both edge magnetizations reach their maximum value; the first one is characterized by an intralayer ferromagnetic coupling between the magnetizations at opposite edges, whereas in the second state that coupling is antiferromagnetic. The band structure, the location of the edge-state bands and the local density of states resolved in spin are calculated in order to understand the origins of the edge magnetizations. We have also introduced an electron doping so that the number of electrons in the ribbon unit cell is higher than in neutral case. As a consequence, we have obtained magnetization steps and charge accumulation at the edges of the sample, which are caused by the edge-state flat bands.

  19. Local adaptation at range edges: comparing elevation and latitudinal gradients.

    PubMed

    Halbritter, A H; Billeter, R; Edwards, P J; Alexander, J M

    2015-10-01

    Local adaptation at range edges influences species' distributions and how they respond to environmental change. However, the factors that affect adaptation, including gene flow and local selection pressures, are likely to vary across different types of range edge. We performed a reciprocal transplant experiment to investigate local adaptation in populations of Plantago lanceolata and P. major from central locations in their European range and from their latitudinal and elevation range edges (in northern Scandinavia and Swiss Alps, respectively). We also characterized patterns of genetic diversity and differentiation in populations using molecular markers. Range-centre plants of P. major were adapted to conditions at the range centre, but performed similarly to range-edge plants when grown at the range edges. There was no evidence for local adaptation when comparing central and edge populations of P. lanceolata. However, plants of both species from high elevation were locally adapted when compared with plants from high latitude, although the reverse was not true. This asymmetry was associated with greater genetic diversity and less genetic differentiation over the elevation gradient than over the latitudinal gradient. Our results suggest that adaptation in some range-edge populations could increase their performance following climate change. However, responses are likely to differ along elevation and latitudinal gradients, with adaptation more likely at high-elevation. Furthermore, based upon these results, we suggest that gene flow is unlikely to constrain adaptation in range-edge populations of these species.

  20. Role of edge turbulence in detached divertor plasmas

    NASA Astrophysics Data System (ADS)

    Gang, F. Y.; Sigmar, D. J.; Krasheninnikov, S. I.

    1996-04-01

    The role of edge turbulence in detached divertor plasmas is investigated. It is shown that the edge turbulence, through poloidal transport of parallel momentum, can produce a significant plasma pressure drop along the magnetic field lines toward the divertor plate, a feature that characterizes the detached divertor plasma regime.

  1. Surface versus Edge-Based Determinants of Visual Recognition.

    ERIC Educational Resources Information Center

    Biederman, Irving; Ju, Ginny

    1988-01-01

    The latency at which objects could be identified by 126 subjects was compared through line drawings (edge-based) or color photography (surface depiction). The line drawing was identified about as quickly as the photograph; primal access to a mental representation of an object can be modeled from an edge-based description. (SLD)

  2. Numerical study of delta wing leading edge blowing

    NASA Technical Reports Server (NTRS)

    Yeh, David; Tavella, Domingo; Roberts, Leonard

    1988-01-01

    Spanwise and tangential leading edge blowing as a means of controlling the position and strength of the leading edge vortices are studied by numerical solution of the three-dimensional Navier-Stokes equations. The leading edge jet is simulated by defining a permeable boundary, corresponding to the jet slot, where suitable boundary conditions are implemented. Numerical results are shown to compare favorably with experimental measurements. It is found that the use of spanwise leading edge blowing at moderate angle of attack magnifies the size and strength of the leading edge vortices, and moves the vortex cores outboard and upward. The increase in lift primarily comes from the greater nonlinear vortex lift. However, spanwise blowing causes earlier vortex breakdown, thus decreasing the stall angle. The effects of tangential blowing at low to moderate angles of attack tend to reduce the pressure peaks associated with leading edge vortices and to increase the suction peak around the leading edge, so that the integrated value of the surface pressure remains about the same. Tangential leading edge blowing in post-stall conditions is shown to re-establish vortical flow and delay vortex bursting, thus increasing C sub L sub max and stall angle.

  3. Evolution of Landau levels into edge states in graphene.

    PubMed

    Li, Guohong; Luican-Mayer, Adina; Abanin, Dmitry; Levitov, Leonid; Andrei, Eva Y

    2013-01-01

    Two-dimensional electron systems in the presence of a magnetic field support topologically ordered states, in which the coexistence of an insulating bulk with conducting one-dimensional chiral edge states gives rise to the quantum Hall effect. For systems confined by sharp boundaries, theory predicts a unique edge-bulk correspondence, which is central to proposals of quantum Hall-based topological qubits. However, in conventional semiconductor-based two-dimensional electron systems, these elegant concepts are difficult to realize, because edge-state reconstruction due to soft boundaries destroys the edge-bulk correspondence. Here we use scanning tunnelling microscopy and spectroscopy to follow the spatial evolution of electronic (Landau) levels towards an edge of graphene supported above a graphite substrate. We observe no edge-state reconstruction, in agreement with calculations based on an atomically sharp boundary. Our results single out graphene as a system where the edge structure can be controlled and the edge-bulk correspondence is preserved.

  4. Local adaptation at range edges: comparing elevation and latitudinal gradients.

    PubMed

    Halbritter, A H; Billeter, R; Edwards, P J; Alexander, J M

    2015-10-01

    Local adaptation at range edges influences species' distributions and how they respond to environmental change. However, the factors that affect adaptation, including gene flow and local selection pressures, are likely to vary across different types of range edge. We performed a reciprocal transplant experiment to investigate local adaptation in populations of Plantago lanceolata and P. major from central locations in their European range and from their latitudinal and elevation range edges (in northern Scandinavia and Swiss Alps, respectively). We also characterized patterns of genetic diversity and differentiation in populations using molecular markers. Range-centre plants of P. major were adapted to conditions at the range centre, but performed similarly to range-edge plants when grown at the range edges. There was no evidence for local adaptation when comparing central and edge populations of P. lanceolata. However, plants of both species from high elevation were locally adapted when compared with plants from high latitude, although the reverse was not true. This asymmetry was associated with greater genetic diversity and less genetic differentiation over the elevation gradient than over the latitudinal gradient. Our results suggest that adaptation in some range-edge populations could increase their performance following climate change. However, responses are likely to differ along elevation and latitudinal gradients, with adaptation more likely at high-elevation. Furthermore, based upon these results, we suggest that gene flow is unlikely to constrain adaptation in range-edge populations of these species. PMID:26201435

  5. Fractal Analysis of Grain Cutting Edge Wear in Superabrasive Grinding

    NASA Astrophysics Data System (ADS)

    Ichida, Yoshio; Sato, Ryunosuke; Fujimoto, Masakazu; Tanaka, Hiromichi

    This paper deals with a fractal analysis of the wear behavior of the grain cutting edges in superabrasive grinding. Fundamental overcut fly grinding experiments for producing individual straight grooves using a grinding tool with multiple grits are carried out to clarify the wear characteristics of the grain cutting edges in the grinding process and then the change in three-dimensional profile of the cutting edge measured with a multiprobe SEM is evaluated on the basis of fractal analysis. The main results are summarized as follows: (1) Fractal dimension for the contour line of the fine cutting edge formed by micro fracture shows a higher value than that of cutting edge formed by attritious wear or large fracture. (2) Fractal dimension for cBN grain cutting edge mainly formed by micro fracture tends to take a higher value than that for diamond grain cutting edge mainly formed by attritious wear. (3) The complex change in shape of the cutting edge with the progress of grinding process can be quantitatively evaluated by means of fractal analysis.

  6. Spiraling Edge: Fast Surface Reconstruction from Partially Organized Sample Points

    SciTech Connect

    Angel, E.; Crossno, P.

    1999-01-06

    Many applications produce three-dimensional points that must be further processed to generate a surface. Surface reconstruction algorithms that start with a set of unorganized points are extremely time-consuming. Often, however, points are generated such that there is additional information available to the reconstruction algorithm. We present a specialized algorithm for surface reconstruction that is three orders of magnitude faster than algorithms for the general case. In addition to sample point locations, our algorithm starts with normal information and knowledge of each point's neighbors. Our algorithm produces a localized approximation to the surface by creating a star-shaped triangulation between a point and a subset of its nearest neighbors. This surface patch is extended by locally triangulating each of the points along the edge of the patch. As each edge point is triangulated, it is removed from the edge and new edge points along the patch's edge are inserted in its place. The updated edge spirals out over the surface until the edge encounters a surface boundary and stops growing in that direction, or until the edge reduces to a small hole that fills itself in.

  7. Detecting the Edge of the Tongue: A Tutorial

    ERIC Educational Resources Information Center

    Iskarous, Khalil

    2005-01-01

    The goal of this paper is to provide a tutorial introduction to the topic of edge detection of the tongue from ultrasound scans for researchers in speech science and phonetics. The method introduced here is Active Contours (also called snakes), a method for searching for an edge, assuming that it is a smooth curve in the image data. The advantage…

  8. Roles of edge weights on epidemic spreading dynamics

    NASA Astrophysics Data System (ADS)

    Zhan, Xiu-Xiu; Liu, Chuang; Zhang, Zi-Ke; Sun, Gui-Quan

    2016-08-01

    Epidemic spreading on complex networks has attracted much attention in recent years. A large number of studies have focused on investigating the impacts of network topology on spreading dynamics. However, the weighted network is very common in real systems, and we attempt to study the role of edge weights on epidemic spreading. In this work, the spreading process was presented as the SIS model and three edge-breaking strategies according to the weight of the SI links were performed simultaneously, which was used to illustrate the influence of the edge weights. Simulation results on three real networks showed the different spreading patterns of different edge-breaking strategies, which in turn indicated the influence of edge weights on the spreading process. Therefore we can take different measures at different periods according to the edge weights to impede the epidemic. In addition, the detailed analyses of relationship between the edge weight and the network structure was given to interpret the role of edge weights in the epidemic spreading process.

  9. Heat-Pipe-Cooled Leading Edges for Hypersonic Vehicles

    NASA Technical Reports Server (NTRS)

    Glass, David E.

    2006-01-01

    Heat pipes can be used to effectively cool wing leading edges of hypersonic vehicles. . Heat-pipe leading edge development. Design validation heat pipe testing confirmed design. Three heat pipes embedded and tested in C/C. Single J-tube heat pipe fabricated and testing initiated. HPCLE work is currently underway at several locations.

  10. Temperature dependence of the reconstruction of zigzag edges in graphene.

    PubMed

    He, Kuang; Robertson, Alex W; Fan, Ye; Allen, Christopher S; Lin, Yung-Chang; Suenaga, Kazu; Kirkland, Angus I; Warner, Jamie H

    2015-05-26

    We examine the temperature dependence of graphene edge terminations at the atomic scale using an in situ heating holder within an aberration-corrected transmission electron microscope. The relative ratios of armchair, zigzag, and reconstructed zigzag edges from over 350 frames at each temperature are measured. Below 400 °C, the edges are dominated by zigzag terminations, but above 600 °C, this changes dramatically, with edges dominated by armchair and reconstructed zigzag edges. We show that at low temperature chemical etching effects dominate and cause deviation to the thermodynamics of the system. At high temperatures (600 and 800 °C), adsorbates are evaporated from the surface of graphene and chemical etching effects are significantly reduced, enabling the thermodynamic distribution of edge types to be observed. The growth rate of holes at high temperature is also shown to be slower than at room temperature, indicative of the reduced chemical etching process. These results provide important insights into the role of chemical etching effects in the hole formation, edge sputtering, and edge reconstruction in graphene.

  11. Tunnelling between the edges of two lateral quantum Hall systems

    PubMed

    Kang; Stormer; Pfeiffer; Baldwin; West

    2000-01-01

    The edge of a two-dimensional electron system in a magnetic field consists of one-dimensional channels that arise from the confining electric field at the edge of the system. The crossed electric and magnetic fields cause electrons to drift parallel to the sample boundary, creating a chiral current that travels along the edge in only one direction. In an ideal two-dimensional electron system in the quantum Hall regime, all the current flows along the edge. Quantization of the Hall resistance arises from occupation of N one-dimensional edge channels, each contributing a conductance of e2/h. Here we report differential conductance measurements, in the integer quantum Hall regime, of tunnelling between the edges of a pair of two-dimensional electron systems that are separated by an atomically precise, high-quality, tunnel barrier. The resultant interaction between the edge states leads to the formation of new energy gaps and an intriguing dispersion relation for electrons travelling along the barrier: for example, we see a persistent conductance peak at zero bias voltage and an absence of tunnelling features due to electron spin. These features are unexpected and are not consistent with a model of weakly interacting edge states. Remnant disorder along the barrier and charge screening may each play a role, although detailed numerical studies will be required to elucidate these effects.

  12. Analysis of light scattering from a cutting tool edge.

    PubMed

    Wang, H; Malacara, D

    1994-07-01

    The scattering of light from cutting tools is studied. The contribution of cutting tool edge parameters (height and width) to scattering patterns and the influence of side surface roughness on scattering patterns are investigated. An angle-limited integrated scattering method is developed and analyzed for fast determination of edge parameters.

  13. Ideal Stability of the Tokamak H--mode Edge Region

    NASA Astrophysics Data System (ADS)

    Wilson, H. R.

    1998-11-01

    Tokamak performance is often controlled by stability of the edge plasma. Consistent with ``stiff'' transport models, the confinement in tokamak discharges is strongly correlated with the magnitude of the edge pressure pedestal which is limited by MHD stability. Furthermore, the high performance ELM-free H--modes are terminated by low toroidal mode number n, MHD modes driven by high edge pressure gradient, and edge current. We have evaluated low n modes using the δ W code GATO, and both high edge pressure gradient and high edge current density are found to destabilize the n=1, 2, and 3 ideal modes. We have included the self-consistent bootstrap current in the equilibria generation, and have completed a thorough survey of the effects of plasma shape and edge pressure profiles on the edge ballooning stability. The bootstrap current density helps to provide access to the second regime of stability, which is easier for: higher elongation, intermediate triangularity, larger aspect ratio, narrower pedestal width, and higher q_95. The intermediate n stability is being evaluated using a high-mode-number peeling/ ballooning mode model,(J.W. Connor, R.J. Hastie, H.R. Wilson, and R.L. Miller, Phys. Plasmas 5), 2687 (1998). where a critical role is played by the edge current density. This edge model describes the interaction of peeling mode (current driven) and ballooning mode (pressure driven) effects at high, but finite, mode number; a modified ballooning mode formalism is shown to be valid at the plasma edge. Based upon this edge model, a 2D eigenvalue code has been written to determine the stability of these modes for arbitrary shape cross sections, and edge pressure and current profiles including bootstrap current effects. This model suggests a power threshold for L--H transitions and provides a plausible explanation for an ELM cycle. Results will be presented for the pressure gradient and edge current density stability boundaries for a range of shapes and pedestal widths

  14. Edge-Flames in Von Karman Swirling Flows

    NASA Technical Reports Server (NTRS)

    Nayagam, Vedha; Williams, Forman A.

    1999-01-01

    Classical understanding of diffusion flames dictates that they, unlike the premixed flames, do not possess a characteristic propagation velocity and are constrained by stoichiometric requirements at the flame surface. However, it has been commonly observed that when local extinction occurs within a diffusion flame sheet, the edges that are formed propagate with distinct speeds. In general, the propagation speed of these edges depend on their geometrical shape (concave, convex, or straight) among other factors. Recently, Buckmaster investigated the dynamics of straight diffusion flame edges separating burning and quenched regions using simplified one-dimensional models. He showed that these flame edges can have positive, negative, or zero velocity depending on the Damkoehler number of the equilibrium diffusion flame that support them. It was also shown that this unsteady flame-edge behavior is intrinsically linked to S-curve behavior of the diffusion flame with varying Damkoehler number. When the system Damkoehler number lies between the extinction and ignition limits, flame edges can propagate as an "ignition wave" or as a "failure wave," and for a critical Damkoehler number remain as a stationary flame-edge. We have extend Buckmaster's 1-d model to more general edge-flame configurations where the edges appear as "flame holes" or as "flame disks". These two configurations along with the straight-edge case cover the entire range of possible edge-flame geometry observable in planar diffusion-flame sheets. A generalized map of edge-flame propagation velocities as a function of the system Damkoehler number and the edge-flame radius is presented. Experimentally we show that edge flames can be created using diffusion flames embedded in von Karman boundary layers. In a von Karman boundary layer, the flow is generated by spinning a solid (fuel) disk in a quiescent ambient gas. Under normal gravity we were able to produce "flame disks" over a range of fuel-disk rotational

  15. Naegleria fowleri: contact-dependent secretion of electrondense granules (EDG).

    PubMed

    Chávez-Munguía, Bibiana; Villatoro, Lizbeth Salazar; Omaña-Molina, Maritza; Rodríguez-Monroy, Marco Aurelio; Segovia-Gamboa, Norma; Martínez-Palomo, Adolfo

    2014-07-01

    The free living amoeba Naegleria fowleri is pathogenic to humans but also to other mammalians. These amoebae may invade the nasal mucosa and migrate into the brain causing cerebral hemorrhagic necrosis, a rapidly fatal infection. Knowledge of the cytolytic mechanism involved in the destruction of brain tissues by Naegleria trophozoites is limited. In other amoebic species, such as Entamoeba histolytica, we have previously reported the possible lytic role of small cytoplasmic components endowed with proteolytic activities, known as electrondense granules (EDG). Using transmission electron microscopy we now report that EDG, seldom found in long term cultured N. fowleri, are present in abundance in trophozoites recovered from experimental mice brain lesions. Numerous EDG were also observed in amoebae incubated with collagen substrates or cultured epithelial cells. SDS-PAGE assays of concentrated supernatants of these trophozoites, containing EDG, revealed proteolytic activities. These results suggest that EDG may have a clear role in the cytopathic mechanisms of this pathogenic amoeba. PMID:24721258

  16. Living on the edge: a review of the literature.

    PubMed

    PetersonLund, Robin R

    2013-10-01

    A comprehensive review of the literature of the universal experience of living on the edge is discussed. Literature was reviewed from biology, criminology, ecology, economics, ethics, finance, fine arts, historical biography, medicine, nursing, philosophy, physiology, psychology, sociology, and theology. Three themes emerged with this literature review: living on the edge as a sacred place one travels to or where one lives, living on the edge as a choice in taking risks and surviving danger, and living on the edge as engaging with health experiences in which persons and nurses coparticipate. Living on the edge is a visionary quest into a new frontier that holds illimitable possibilities that transform the world. The literature is discussed according to theoretical and research findings. PMID:24085664

  17. Fabrication of ultra-fine nanostructures using edge transfer printing

    NASA Astrophysics Data System (ADS)

    Xue, Mianqi; Li, Fengwang; Cao, Tingbing

    2012-03-01

    The exploration of new methods and techniques for application in diverse fields, such as photonics, microfluidics, biotechnology and flexible electronics is of increasing scientific and technical interest for multiple uses over distance of 10-100 nm. This article discusses edge transfer printing -- a series of unconventional methods derived from soft lithography for nanofabrication. It possesses the advantages of easy fabrication, low-cost and great serviceability. In this paper, we show how to produce exposed edges and use various materials for edge transfer printing, while nanoskiving, nanotransfer edge printing and tunable cracking for nanogaps are introduced. Besides this, different functional materials, such as metals, inorganic semiconductors and polymers, as well as localised heating and charge patterning, are described here as unconventional ``inks'' for printing. Edge transfer printing, which can effectively produce sub-100 nm scale ultra-fine structures, has broad applications, including metallic nanowires as nanoelectrodes, semiconductor nanowires for chemical sensors, heterostructures of organic semiconductors, plasmonic devices and so forth.

  18. Detecting the edge of the tongue: a tutorial.

    PubMed

    Iskarous, Khalil

    2005-01-01

    The goal of this paper is to provide a tutorial introduction to the topic of edge detection of the tongue from ultrasound scans for researchers in speech science and phonetics. The method introduced here is Active Contours (also called snakes), a method for searching for an edge, assuming that it is a smooth curve in the image data. The advantage of this approach is that it is robust to the noisy speckle that clouds edges. This method has been implemented in several software packages currently used for detecting the edge of the tongue in ultrasound images. The tutorial concludes with an overview of the scale-space and Kalman filter approaches, state-of-the-art developments in image processing that will likely influence work on tongue edge detection in the coming years.

  19. An Adaptive Immune Genetic Algorithm for Edge Detection

    NASA Astrophysics Data System (ADS)

    Li, Ying; Bai, Bendu; Zhang, Yanning

    An adaptive immune genetic algorithm (AIGA) based on cost minimization technique method for edge detection is proposed. The proposed AIGA recommends the use of adaptive probabilities of crossover, mutation and immune operation, and a geometric annealing schedule in immune operator to realize the twin goals of maintaining diversity in the population and sustaining the fast convergence rate in solving the complex problems such as edge detection. Furthermore, AIGA can effectively exploit some prior knowledge and information of the local edge structure in the edge image to make vaccines, which results in much better local search ability of AIGA than that of the canonical genetic algorithm. Experimental results on gray-scale images show the proposed algorithm perform well in terms of quality of the final edge image, rate of convergence and robustness to noise.

  20. Partially turbulated trailing edge cooling passages for gas turbine nozzles

    DOEpatents

    Thatcher, Jonathan Carl; Burdgick, Steven Sebastian

    2001-01-01

    A plurality of passages are spaced one from the other along the length of a trailing edge of a nozzle vane in a gas turbine. The passages lie in communication with a cavity in the vane for flowing cooling air from the cavity through the passages through the tip of the trailing edge into the hot gas path. Each passage is partially turbulated and includes ribs in an aft portion thereof to provide enhanced cooling effects adjacent the tip of the trailing edge. The major portions of the passages are smooth bore. By this arrangement, reduced temperature gradients across the trailing edge metal are provided. Additionally, the inlets to each of the passages have a restriction whereby a reduced magnitude of compressor bleed discharge air is utilized for trailing edge cooling purposes.

  1. Investigating Actinide Molecular Adducts From Absorption Edge Spectroscopy

    SciTech Connect

    Den Auwer, C.; Conradson, S.D.; Guilbaud, P.; Moisy, P.; Mustre de Leon, J.; Simoni, E.; /SLAC, SSRL

    2006-10-27

    Although Absorption Edge Spectroscopy has been widely applied to the speciation of actinide elements, specifically at the L{sub III} edge, understanding and interpretation of actinide edge spectra are not complete. In that sense, semi-quantitative analysis is scarce. In this paper, different aspects of edge simulation are presented, including semi-quantitative approaches. Comparison is made between various actinyl (U, Np) aquo or hydroxy compounds. An excursion into transition metal osmium chemistry allows us to compare the structurally related osmyl and uranyl hydroxides. The edge shape and characteristic features are discussed within the multiple scattering picture and the role of the first coordination sphere as well as contributions from the water solvent are described.

  2. Edge states and phase diagram for graphene under polarized light

    DOE PAGES

    Wang, Yi -Xiang; Li, Fuxiang

    2016-03-22

    In this paper, we investigate the topological phase transitions in graphene under the modulation of circularly polarized light, by analyzing the changes of edge states and its topological structures. A full phase diagram, with several different topological phases, is presented in the parameter space spanned by the driving frequency and light strength. We find that the high-Chern number behavior is very common in the driven system. While the one-photon resonance can create the chiral edge states in the π-gap, the two-photon resonance will induce the counter-propagating edge modes in the zero-energy gap. When the driving light strength is strong, themore » number and even the chirality of the edge states may change in the π-gap. The robustness of the edge states to disorder potential is also examined. We close by discussing the feasibility of experimental proposals.« less

  3. Naegleria fowleri: contact-dependent secretion of electrondense granules (EDG).

    PubMed

    Chávez-Munguía, Bibiana; Villatoro, Lizbeth Salazar; Omaña-Molina, Maritza; Rodríguez-Monroy, Marco Aurelio; Segovia-Gamboa, Norma; Martínez-Palomo, Adolfo

    2014-07-01

    The free living amoeba Naegleria fowleri is pathogenic to humans but also to other mammalians. These amoebae may invade the nasal mucosa and migrate into the brain causing cerebral hemorrhagic necrosis, a rapidly fatal infection. Knowledge of the cytolytic mechanism involved in the destruction of brain tissues by Naegleria trophozoites is limited. In other amoebic species, such as Entamoeba histolytica, we have previously reported the possible lytic role of small cytoplasmic components endowed with proteolytic activities, known as electrondense granules (EDG). Using transmission electron microscopy we now report that EDG, seldom found in long term cultured N. fowleri, are present in abundance in trophozoites recovered from experimental mice brain lesions. Numerous EDG were also observed in amoebae incubated with collagen substrates or cultured epithelial cells. SDS-PAGE assays of concentrated supernatants of these trophozoites, containing EDG, revealed proteolytic activities. These results suggest that EDG may have a clear role in the cytopathic mechanisms of this pathogenic amoeba.

  4. Edge profile measurements using Thomson scattering on the KSTAR tokamak.

    PubMed

    Lee, J H; Oh, S; Lee, W R; Ko, W H; Kim, K P; Lee, K D; Jeon, Y M; Yoon, S W; Cho, K W; Narihara, K; Yamada, I; Yasuhara, R; Hatae, T; Yatsuka, E; Ono, T; Hong, J H

    2014-11-01

    In the KSTAR Tokamak, a "Tangential Thomson Scattering" (TTS) diagnostic system has been designed and installed to measure electron density and temperature profiles. In the edge system, TTS has 12 optical fiber bundles to measure the edge profiles with 10-15 mm spatial resolution. These 12 optical fibers and their spatial resolution are not enough to measure the pedestal width with a high accuracy but allow observations of L-H transition or H-L transitions at the edge. For these measurements, the prototype ITER edge Thomson Nd:YAG laser system manufactured by JAEA in Japan is installed. In this paper, the KSTAR TTS system is briefly described and some TTS edge profiles are presented and compared against the KSTAR Charge Exchange Spectroscopy and other diagnostics. The future upgrade plan of the system is also discussed in this paper.

  5. Edge singularities and structure of the 3-D Williams expansion

    NASA Astrophysics Data System (ADS)

    Apel, Thomas; Leguillon, Dominique; Pester, Cornelia; Yosibash, Zohar

    2008-08-01

    The elastic solution in a vicinity of a re-entrant wedge can be described by a Williams like expansion in terms of powers of the distance to a point on the edge. This expansion has a particular structure due to the invariance of the problem by translation parallel to the edge. We show here that some terms, so-called primary solutions, derive directly from solutions to the 2-D corner problem posed in the orthogonal cross section of the domain. The others, baptized shadow functions, derive of the primary solutions by integration along the axis parallel to the edge. This 3-D Williams expansion is shown to be equivalent to the edge expansion proposed by Costabel et al. [M. Costabel, M. Dauge, Z. Yosibash, A quasidual function method for extracting edge stress intensity functions, SIAM J. Math. Anal. 35 (5) (2004) 1177-1202]. To cite this article: T. Apel et al., C. R. Mecanique 336 (2008).

  6. Edge states and phase diagram for graphene under polarized light

    NASA Astrophysics Data System (ADS)

    Wang, Yi-Xiang; Li, Fuxiang

    2016-07-01

    In this work, we investigate the topological phase transitions in graphene under the modulation of circularly polarized light, by analyzing the changes of edge states and its topological structures. A full phase diagram, with several different topological phases, is presented in the parameter space spanned by the driving frequency and light strength. We find that the high-Chern number behavior is very common in the driven system. While the one-photon resonance can create the chiral edge states in the π-gap, the two-photon resonance will induce the counter-propagating edge modes in the zero-energy gap. When the driving light strength is strong, the number and even the chirality of the edge states may change in the π-gap. The robustness of the edge states to disorder potential is also examined. We close by discussing the feasibility of experimental proposals.

  7. Fuzzy Index to Evaluate Edge Detection in Digital Images

    PubMed Central

    Perez-Ornelas, Felicitas; Mendoza, Olivia; Melin, Patricia; Castro, Juan R.; Rodriguez-Diaz, Antonio; Castillo, Oscar

    2015-01-01

    In literature, we can find different metrics to evaluate the detected edges in digital images, like Pratt's figure of merit (FOM), Jaccard’s index (JI) and Dice’s coefficient (DC). These metrics compare two images, the first one is the reference edges image, and the second one is the detected edges image. It is important to mention that all existing metrics must binarize images before their evaluation. Binarization step causes information to be lost because an incomplete image is being evaluated. In this paper, we propose a fuzzy index (FI) for edge evaluation that does not use a binarization step. In order to process all detected edges, images are represented in their fuzzy form and all calculations are made with fuzzy sets operators and fuzzy Euclidean distance between both images. Our proposed index is compared to the most used metrics using synthetic images, with good results. PMID:26115362

  8. Trailing edge flow conditions as a factor in airfoil design

    NASA Technical Reports Server (NTRS)

    Ormsbee, A. I.; Maughmer, M. D.

    1984-01-01

    Some new developments relevant to the design of single-element airfoils using potential flow methods are presented. In particular, the role played by the non-dimensional trailing edge velocity in design is considered and the relationship between the specified value and the resulting airfoil geometry is explored. In addition, the ramifications of the unbounded trailing edge pressure gradients generally present in the potential flow solution of the flow over an airfoil are examined, and the conditions necessary to obtain a class of airfoils having finite trailing edge pressure gradients developed. The incorporation of these conditions into the inverse method of Eppler is presented and the modified scheme employed to generate a number of airfoils for consideration. The detailed viscous analysis of airfoils having finite trailing edge pressure gradients demonstrates a reduction in the strong inviscid-viscid interactions generally present near the trailing edge of an airfoil.

  9. Schools and Schooling: Anthropological Approaches.

    ERIC Educational Resources Information Center

    Johnson, Norris Brock

    The thesis presented in this paper is that school failure among minority subgroups is related to the nature, characteristics, and function of public schooling as well as to the social structural position of the subgroups of which these children are members. An overview of some ethnographic studies of schools and the process of schooling is…

  10. Characterization of a novel sphingosine 1-phosphate receptor, Edg-8.

    PubMed

    Im, D S; Heise, C E; Ancellin, N; O'Dowd, B F; Shei, G J; Heavens, R P; Rigby, M R; Hla, T; Mandala, S; McAllister, G; George, S R; Lynch, K R

    2000-05-12

    Three G protein-coupled receptors (Edg-1, Edg-3, and Edg-5) for the lysolipid phosphoric acid mediator sphingosine 1-phosphate have been described by molecular cloning. Using a similar sequence that we found in the expressed sequence tag data base, we cloned and characterized of a fourth, high affinity, rat brain sphingosine 1-phosphate receptor, Edg-8. When HEK293T cells were co-transfected with Edg-8 and G protein DNAs, prepared membranes showed sphingosine 1- phosphate-dependent increases in [(35)S]guanosine 5'-(3-O-thio)triphosphate binding with an EC(50) of 90 nm. In a rat hepatoma Rh7777 cell line that exhibits modest endogenous responses to sphingosine 1-phosphate, this lipid mediator inhibited forskolin-driven rises in cAMP by greater than 90% when the cells were transfected with Edg-8 DNA (IC(50) 0.7 nm). This response is blocked fully by prior treatment of cultures with pertussis toxin, thus implicating signaling through G(i/o)alpha proteins. Furthermore, Xenopus oocytes exhibit a calcium response to sphingosine 1-phosphate after injection of Edg-8 mRNA, but only when oocytes are co-injected with chimeric G(q/i)alpha protein mRNA. Membranes from HEK293T and Rh7777 cell cultures expressing Edg-8 exhibited high affinity (K(D) = 2 nm) binding for radiolabeled sphingosine 1-phosphate. Rat Edg-8 RNA is expressed in spleen and throughout adult rat brain where in situ hybridization revealed it to be associated with white matter. Together our data demonstrate that Edg-8 is a high affinity sphingosine 1-phosphate receptor that couples to G(i/o)alpha proteins and is expressed predominantly by oligodendrocytes and/or fibrous astrocytes in the rat brain.

  11. Full-waveform data for building roof step edge localization

    NASA Astrophysics Data System (ADS)

    Słota, Małgorzata

    2015-08-01

    Airborne laser scanning data perfectly represent flat or gently sloped areas; to date, however, accurate breakline detection is the main drawback of this technique. This issue becomes particularly important in the case of modeling buildings, where accuracy higher than the footprint size is often required. This article covers several issues related to full-waveform data registered on building step edges. First, the full-waveform data simulator was developed and presented in this paper. Second, this article provides a full description of the changes in echo amplitude, echo width and returned power caused by the presence of edges within the laser footprint. Additionally, two important properties of step edge echoes, peak shift and echo asymmetry, were noted and described. It was shown that these properties lead to incorrect echo positioning along the laser center line and can significantly reduce the edge points' accuracy. For these reasons and because all points are aligned with the center of the beam, regardless of the actual target position within the beam footprint, we can state that step edge points require geometric corrections. This article presents a novel algorithm for the refinement of step edge points. The main distinguishing advantage of the developed algorithm is the fact that none of the additional data, such as emitted signal parameters, beam divergence, approximate edge geometry or scanning settings, are required. The proposed algorithm works only on georeferenced profiles of reflected laser energy. Another major advantage is the simplicity of the calculation, allowing for very efficient data processing. Additionally, the developed method of point correction allows for the accurate determination of points lying on edges and edge point densification. For this reason, fully automatic localization of building roof step edges based on LiDAR full-waveform data with higher accuracy than the size of the lidar footprint is feasible.

  12. GSFC Cutting Edge Avionics Technologies for Spacecraft

    NASA Technical Reports Server (NTRS)

    Luers, Philip J.; Culver, Harry L.; Plante, Jeannette

    1998-01-01

    With the launch of NASA's first fiber optic bus on SAMPEX in 1992, GSFC has ushered in an era of new technology development and insertion into flight programs. Predating such programs the Lewis and Clark missions and the New Millenium Program, GSFC has spearheaded the drive to use cutting edge technologies on spacecraft for three reasons: to enable next generation Space and Earth Science, to shorten spacecraft development schedules, and to reduce the cost of NASA missions. The technologies developed have addressed three focus areas: standard interface components, high performance processing, and high-density packaging techniques enabling lower cost systems. To realize the benefits of standard interface components GSFC has developed and utilized radiation hardened/tolerant devices such as PCI target ASICs, Parallel Fiber Optic Data Bus terminals, MIL-STD-1773 and AS1773 transceivers, and Essential Services Node. High performance processing has been the focus of the Mongoose I and Mongoose V rad-hard 32-bit processor programs as well as the SMEX-Lite Computation Hub. High-density packaging techniques have resulted in 3-D stack DRAM packages and Chip-On-Board processes. Lower cost systems have been demonstrated by judiciously using all of our technology developments to enable "plug and play" scalable architectures. The paper will present a survey of development and insertion experiences for the above technologies, as well as future plans to enable more "better, faster, cheaper" spacecraft. Details of ongoing GSFC programs such as Ultra-Low Power electronics, Rad-Hard FPGAs, PCI master ASICs, and Next Generation Mongoose processors.

  13. Microcalorimetry and the transition-edge sensor

    SciTech Connect

    Lindeman, M A

    2000-04-01

    Many scientific and industrial applications call for quantum-efficient high-energy-resolution microcalorimeters for the measurement of x rays. The applications driving the development of these detectors involve the measurement of faint sources of x rays in which few photons reach the detector. Interesting astrophysical applications for these microcalorimeters include the measurement of composition and temperatures of stellar atmospheres and diffuse interstellar plasmas. Other applications of microcalorimeter technology include x-ray fluorescence (XRF) measurements of industrial or scientific samples. We are attempting to develop microcalorimeters with energy resolutions of several eV because many sources (such as celestial plasmas) contain combinations of elements producing emission lines spaced only a few eV apart. Our microcalorimeters consist of a metal-film absorber (250 {micro}m x 250{micro}m x 3 {micro}m of copper) coupled to a superconducting transition-edge-sensor (TES) thermometer. This microcalorimeter demonstrated an energy resolution of 42 eV (FWHM) at 6 keV, excellent linearity, and showed no evidence of position dependent response. The response of our microcalorimeters depends both on the temperature of the microcalorimeter and on the electrical current conducted through the TES thermometer. We present a microcalorimeter model that extends previous microcalorimeter theory to include additional current dependent effects. The model makes predictions about the effects of various forms of noise. In addition, the model helps us to understand what measurements are useful for characterizing TES microcalorimeters. While the energy resolution we obtained was quite good (twice as good as conventional semiconductor-based x-ray detectors), the obtained resolution was not as good as expected, due to excess noise from fluctuations in the TES thermometer. The energy resolution of future TES microcalorimeters can be improved by redesigning the calorimeters to

  14. Nursing ethics in the seventh-day adventist religious tradition.

    PubMed

    Taylor, Elizabeth Johnston; Carr, Mark F

    2009-11-01

    Nurses' religious beliefs influence their motivations and perspectives, including their practice of ethics in nursing care. When the impact of these beliefs is not recognized, great potential for unethical nursing care exists. Thus, this article examines how the theology of one religious tradition, Seventh-day Adventism (SDA), could affect nurses. An overview of SDA history and beliefs is presented, which explains why 'medical missionary' work is central to SDAs. Theological foundations that would permeate an SDA nurse's view of the nursing metaparadigm concepts of person, health, environment (i.e. community), and nursing (i.e. service) are presented. The ethical principles guiding SDA nurses (i.e. principled, case-based, and care ethics) and the implications of these theological foundations for nurses are noted in a case study.

  15. Theoretical study of edge states in BC2N nanoribbons with zigzag edges

    PubMed Central

    2013-01-01

    In this paper, electronic properties of BC2N nanoribbons with zigzag edges are studied theoretically using a tight binding model and the first-principles calculations based on the density functional theories. The zigzag BC2N nanoribbons have the flat bands when the atoms are arranged as B-C-N-C along the zigzag lines. In this arrangement, the effect of charge transfer is averaged since B and N atoms are doped in same sublattice sites. This effect is important for not only the formation of flat bands but also for the validity of the tight binding model for such system. PMID:23902682

  16. RING EDGE WAVES AND THE MASSES OF NEARBY SATELLITES

    SciTech Connect

    Weiss, John W.; Porco, Carolyn C.

    2009-07-15

    Moons embedded in gaps within Saturn's main rings generate waves on the gap edges due to their gravitational disturbances. These edge waves can serve as diagnostics for the masses and, in some cases, orbital characteristics of the embedded moons. Although N-body simulations of the edges are far better in inferring masses from edge morphology, the long run-times of this technique often make it impractical. In this paper, we describe a faster approach to narrow the range of masses to explore with N-body simulations, to explore the multidimensional parameter space of edge/moon interactions, and to guide the planning of spacecraft observations. Using numerical, test-particle models and neglecting particle-particle interactions, we demonstrate that the simple analytic theory of the edge waves applies well to Pan in the Encke Gap but breaks down for smaller moons/gaps like Daphnis in the Keeler Gap. Fitting an analytic model to our simulation results allows us to suggest an improved relationship between moon-mass and edge wave amplitude. Numerical methods also grant freedom to explore a wider range of moon and ring orbits than the circular, coplanar case considered by analytic theory. We examine how pre-encounter inclinations and eccentricities affect the properties of the edge waves. In the case where the moon or ring-edge particle orbits initially have eccentric radial variations that are large compared to the gap width, there is considerable variation in edge wave amplitude depending on the orbital phase of the encounter. Inclined moons also affect the edge wave amplitude, potentially significantly, as well as generate vertical waves on the gap-edges. Recent Cassini images acquired as Saturn approaches equinox and the Sun's elevation on the ringplane is extremely low have revealed long shadows associated with the Keeler gap edge waves created by the embedded moon Daphnis. We interpret these as being cast by {approx}1 km high vertical structure in the waves created by

  17. RCUK School-University Partnerships Initiative: Connecting Schools and Universities Together

    ERIC Educational Resources Information Center

    Anderson, Claudine; Williams, Ruth

    2013-01-01

    Connecting schools with cutting edge research and researchers can inspire and motivate young people. There is evidence that bringing contemporary research into the classroom is of key importance, as researchers can act as positive role models for young people and expose students to exciting future study and career options, motivating students to…

  18. Mechanics of mitral valve edge-to-edge-repair and MitraClip procedure.

    PubMed

    Bhattacharya, Shamik; He, Zhaoming

    2015-01-01

    The edge-to-edge repair (ETER) technique has been used as a stand-alone procedure, or as a secondary procedure with ring annuloplasty for degenerative, functional mitral regurgitation, or for mitral regurgitation of other kinds of valvular etiologies. The percutaneous MitraClip technique based on ETER has been used in patients who are inoperable or at high surgical risk. However, adverse events such as residual mitral regurgitation, and clip detachment or fracture indicate that the mechanics underlying these procedures is not well understood. Therefore, current studies on mitral valve functionality and mechanics related to the ETER and MitraClip procedures are reviewed to improve the efficacy and safety of both procedures. Extensive in vivo, in vitro, and in silico studies related to ETER and MitraClip procedures along with MitraClip clinical trial results are presented and discussed herein. The ETER suture force and the mitral valve tissue mechanics and hemodynamics of each procedure are discussed. A quantitative understanding of the interplay of mitral valve components and as to biological response to the procedures remains challenging. Based on mitral valve mechanics, ETER or MitraClip therapy can be optimized to enhance repair efficacy and durability.

  19. Edge-oriented dual-dictionary guided enrichment (EDGE) for MRI-CT image reconstruction.

    PubMed

    Li, Liang; Wang, Bigong; Wang, Ge

    2016-01-01

    In this paper, we formulate the joint/simultaneous X-ray CT and MRI image reconstruction. In particular, a novel algorithm is proposed for MRI image reconstruction from highly under-sampled MRI data and CT images. It consists of two steps. First, a training dataset is generated from a series of well-registered MRI and CT images on the same patients. Then, an initial MRI image of a patient can be reconstructed via edge-oriented dual-dictionary guided enrichment (EDGE) based on the training dataset and a CT image of the patient. Second, an MRI image is reconstructed using the dictionary learning (DL) algorithm from highly under-sampled k-space data and the initial MRI image. Our algorithm can establish a one-to-one correspondence between the two imaging modalities, and obtain a good initial MRI estimation. Both noise-free and noisy simulation studies were performed to evaluate and validate the proposed algorithm. The results with different under-sampling factors show that the proposed algorithm performed significantly better than those reconstructed using the DL algorithm from MRI data alone.

  20. The role of spatiotemporal edges in visibility and visual masking

    PubMed Central

    Macknik, Stephen L.; Martinez-Conde, Susana; Haglund, Michael M.

    2000-01-01

    What parts of a visual stimulus produce the greatest neural signal? Previous studies have explored this question and found that the onset of a stimulus's edge is what excites early visual neurons most strongly. The role of inhibition at the edges of stimuli has remained less clear, however, and the importance of neural responses associated with the termination of stimuli has only recently been examined. Understanding all of these spatiotemporal parameters (the excitation and inhibition evoked by the stimulus's onset and termination, as well as its spatial edges) is crucial if we are to develop a general principle concerning the relationship between neural signals and the parts of the stimulus that generate them. Here, we use visual masking illusions to explore this issue, in combination with human psychophysics, awake behaving primate neurophysiology in the lateral geniculate nucleus of the thalamus, and optical recording in the primary visual cortex of anesthetized monkeys. The edges of the stimulus, rather than its interior, generate the strongest excitatory and inhibitory responses both perceptually and physiologically. These edges can be imaged directly by using optical recording techniques. Excitation and inhibition are moreover most powerful when the stimulus turns both on and off (what might be thought of as the stimulus's temporal edges). We thus conclude that there is a general principle that relates the generation of neural signals (excitatory and inhibitory) to the spatiotemporal edges of stimuli in the early visual system. PMID:10852945

  1. Vortex leading edge flap assembly for supersonic airplanes

    NASA Technical Reports Server (NTRS)

    Rudolph, Peter K. C. (Inventor)

    1997-01-01

    A leading edge flap (16) for supersonic transport airplanes is disclosed. In its stowed position, the leading edge flap forms the lower surface of the wing leading edge up to the horizontal center of the leading edge radius. For low speed operation, the vortex leading edge flap moves forward and rotates down. The upward curve of the flap leading edge triggers flow separation on the flap and rotational flow on the upper surface of the flap (vortex). The rounded shape of the upper fixed leading edge provides the conditions for a controlled reattachment of the flow on the upper wing surface and therefore a stable vortex. The vortex generates lift and a nose-up pitching moment. This improves maximum lift at low speed, reduces attitude for a given lift coefficient and improves lift to drag ratio. The mechanism (27) to move the vortex flap consists of two spanwise supports (24) with two diverging straight tracks (64 and 68) each and a screw drive mechanism (62) in the center of the flap panel (29). The flap motion is essentially normal to the airloads and therefore requires only low actuation forces.

  2. Thermoelectric transport of edge/surface states of topological insulators

    NASA Astrophysics Data System (ADS)

    Murakami, Shuichi; Takahashi, Ryuji

    2011-03-01

    In my talk we theoretically study thermoelectric properties of topological insulators (TI), where novel properties of edge/surface states are expected to appear. As compared to the number of bulk states, the edge/surface states are very few; we therefore consider a narrow ribbon for 2D and a thin slab for 3D TI to make the edge/surface-state transport larger. By considering edge/surface and bulk transport together, we calculate the charge and heat conductivity, and Seebeck coefficient. We find that in 2D TI the bulk and edge transport compete each other in the thermoelectric transport. By lowering temperature, the thermoelectric figure of merit ZT has a minimum, corresponding to the bulk-to-edge crossover, and then increases again at low temperature where the edge state dominates. The crossover is estimated to be at around 5K-10K for 10nm-width ribbon. We also discuss surface state transport for 3D TI as well.

  3. Near-field tsunami edge waves and complex earthquake rupture

    USGS Publications Warehouse

    Geist, Eric L.

    2013-01-01

    The effect of distributed coseismic slip on progressive, near-field edge waves is examined for continental shelf tsunamis. Detailed observations of edge waves are difficult to separate from the other tsunami phases that are observed on tide gauge records. In this study, analytic methods are used to compute tsunami edge waves distributed over a finite number of modes and for uniformly sloping bathymetry. Coseismic displacements from static elastic theory are introduced as initial conditions in calculating the evolution of progressive edge-waves. Both simple crack representations (constant stress drop) and stochastic slip models (heterogeneous stress drop) are tested on a fault with geometry similar to that of the M w = 8.8 2010 Chile earthquake. Crack-like ruptures that are beneath or that span the shoreline result in similar longshore patterns of maximum edge-wave amplitude. Ruptures located farther offshore result in reduced edge-wave excitation, consistent with previous studies. Introduction of stress-drop heterogeneity by way of stochastic slip models results in significantly more variability in longshore edge-wave patterns compared to crack-like ruptures for the same offshore source position. In some cases, regions of high slip that are spatially distinct will yield sub-events, in terms of tsunami generation. Constructive interference of both non-trapped and trapped waves can yield significantly larger tsunamis than those that produced by simple earthquake characterizations.

  4. Edge detection in grayscale imagery using machine learning

    SciTech Connect

    Glocer, K. A.; Perkins, S. J.

    2004-01-01

    Edge detection can be formulated as a binary classification problem at the pixel level with the goal of identifying individual pixels as either on-edge or off-edge. To solve this classification problem we use both fixed and adaptive feature selection in conjunction with a support vector machine. This approach provides a direct data-driven solution and does not require the intermediate step of learning a distribution to perform a likelihood-based classification. Furthermore, the approach can readily be adapted for other image processing tasks. The algorithm was tested on a data set of 50 object images, each associated with a hand-drawn 'ground truth' image. We computed ROC curves to evaluate the performance of the general feature extraction and machine learning approach, and compared that to the standard Canny edge detector and with recent work on statistical edge detection. Using a direct pixel-by-pixel error metric enabled us to compare to the statistical edge detection approach, and our algorithm compared favorably. Using a more 'natural' metric enabled comparision with work by the authors of the image data set, and our algorithm performed comparably to the suite of state-of-art edge detectors in that study.

  5. Elongated Silicon-Carbon Bonds at Graphene Edges.

    PubMed

    Chen, Qu; Robertson, Alex W; He, Kuang; Gong, Chuncheng; Yoon, Euijoon; Kirkland, Angus I; Lee, Gun-Do; Warner, Jamie H

    2016-01-26

    We study the bond lengths of silicon (Si) atoms attached to both armchair and zigzag edges using aberration corrected transmission electron microscopy with monochromation of the electron beam. An in situ heating holder is used to perform imaging of samples at 800 °C in order to reduce chemical etching effects that cause rapid structure changes of graphene edges at room temperature under the electron beam. We provide detailed bond length measurements for Si atoms both attached to edges and also as near edge substitutional dopants. Edge reconstruction is also involved with the addition of Si dopants. Si atoms bonded to the edge of graphene are compared to substitutional dopants in the bulk lattice and reveal reduced out-of-plane distortion and bond elongation. An extended linear array of Si atoms at the edge is found to be energy-favorable due to inter-Si interactions. These results provide detailed structural information about the Si-C bonds in graphene, which may have importance in future catalytic and electronic applications.

  6. Selective edge modification in graphene and graphite by chemical oxidation.

    PubMed

    Yang, Min; Moriyama, Satoshi; Higuchi, Masayoshi

    2014-04-01

    The effect of edge structures in graphene sheets has been well investigated theoretically but most experimental demonstrations of the functionalization have been for the bulk structures because of only a few reports on chemical methods to modify the edges selectively. We herein report a chemical method using the Lemieux-von Rudloff reagent that selectively oxidizes only the edges of graphene sheets. The selective oxidation at the edges of the graphene sheet was confirmed by thermogravimetric analysis (TGA), Raman mapping measurements, and X-ray photoelectron spectroscopy (XPS). The TGA result of the oxidized graphite with different particle sizes showed a slight weight loss at approximately 350 degrees C (2.29% for the middle particles (35 microm)), which indicates thermal decomposition of the oxidized edge part. The Raman mapping measurement in the inner part of graphene sheets didn't detect any defects or translational symmetry breaking after the oxidation. The XPS data clearly showed that the total carbon atom content present as C--O, C==O, and O--C==C increased from 4.65 to 6.18% by the oxidation. Using the obtained edge-oxidized graphene as a starting material, various functionalizations of the edge structure are expected in the future.

  7. Photonic band-edge-induced enhancement in absorption and emission

    NASA Astrophysics Data System (ADS)

    Ummer, Karikkuzhi Variyath; Vijaya, Ramarao

    2015-01-01

    An enhancement in photonic band-edge-induced absorption and emission from rhodamine-B dye doped polystyrene pseudo gap photonic crystals is studied. The band-edge-induced enhancement in absorption is achieved by selecting the incident angle of the excitation beam so that the absorption spectrum of the emitter overlaps the photonic band edge. The band-edge-induced enhancement in emission, on the other hand, is possible with and without an enhancement in band-edge-induced absorption, depending on the collection angle of emission. Through a simple set of measurements with suitably chosen angles for excitation and emission, we achieve a maximum enhancement of 70% in emission intensity with band-edge-induced effects over and above the intrinsic emission in the case of self-assembled opals. This is a comprehensive effort to interpret tunable lasing in opals as well as to predict the wavelength of lasing arising as a result of band-edge-induced distributed feedback effects.

  8. The Red Edge Problem in asteroid band parameter analysis

    NASA Astrophysics Data System (ADS)

    Lindsay, Sean S.; Dunn, Tasha L.; Emery, Joshua P.; Bowles, Neil E.

    2016-04-01

    Near-infrared reflectance spectra of S-type asteroids contain two absorptions at 1 and 2 μm (band I and II) that are diagnostic of mineralogy. A parameterization of these two bands is frequently employed to determine the mineralogy of S(IV) asteroids through the use of ordinary chondrite calibration equations that link the mineralogy to band parameters. The most widely used calibration study uses a Band II terminal wavelength point (red edge) at 2.50 μm. However, due to the limitations of the NIR detectors on prominent telescopes used in asteroid research, spectral data for asteroids are typically only reliable out to 2.45 μm. We refer to this discrepancy as "The Red Edge Problem." In this report, we evaluate the associated errors for measured band area ratios (BAR = Area BII/BI) and calculated relative abundance measurements. We find that the Red Edge Problem is often not the dominant source of error for the observationally limited red edge set at 2.45 μm, but it frequently is for a red edge set at 2.40 μm. The error, however, is one sided and therefore systematic. As such, we provide equations to adjust measured BARs to values with a different red edge definition. We also provide new ol/(ol+px) calibration equations for red edges set at 2.40 and 2.45 μm.

  9. Resilience of southwestern Amazon forests to anthropogenic edge effects.

    PubMed

    Phillips, Oliver L; Rose, Sam; Mendoza, Abel Monteagudo; Vargas, Percy Núñez

    2006-12-01

    Anthropogenic edge effects can compromise the conservation value of mature tropical forests. To date most edge-effect research in Amazonia has concentrated on forests in relatively seasonal locations or with poor soils in the east of the basin. We present the first evaluation from the relatively richer soils of far western Amazonia on the extent to which mature forest biomass, diversity, and composition are affected by edges. In a southwestern Amazonian landscape we surveyed woody plant diversity, species composition, and biomass in 88x0.1 ha samples of unflooded forest that spanned a wide range in soil properties and included samples as close as 50 m and as distant as >10 km from anthropogenic edges. We applied Mantel tests, multiple regression on distance matrices, and other multivariate techniques to identify anthropogenic effects before and after accounting for soil factors and spatial autocorrelation. The distance to the nearest edge, access point, and the geographical center of the nearest community ("anthropogenic-distance effects") all had no detectable effect on tree biomass or species diversity. Anthropogenic-distance effects on tree species composition were also below the limits of detection and were negligible in comparison with natural environmental and spatial factors. Analysis of the data set's capacity to detect anthropogenic effects confirmed that the forests were not severely affected by edges, although because our study had few plots within 100 m of forest edges, our confidence in patterns in the immediate vicinity of edges is limited. It therefore appears that the conservation value of most "edge" forests in this region has not yet been compromised substantially. We caution that because this is one case study it should not be overinterpreted, but one explanation for our findings may be that western Amazonian tree species are naturally faster growing and more disturbance adapted than those farther east.

  10. Vegetation's red edge: a possible spectroscopic biosignature of extraterrestrial plants.

    PubMed

    Seager, S; Turner, E L; Schafer, J; Ford, E B

    2005-06-01

    Earth's deciduous plants have a sharp order-of-magnitude increase in leaf reflectance between approximately 700 and 750 nm wavelength. This strong reflectance of Earth's vegetation suggests that surface biosignatures with sharp spectral features might be detectable in the spectrum of scattered light from a spatially unresolved extrasolar terrestrial planet. We assess the potential of Earth's step-function-like spectroscopic feature, referred to as the "red edge," as a tool for astrobiology. We review the basic characteristics and physical origin of the red edge and summarize its use in astronomy: early spectroscopic efforts to search for vegetation on Mars and recent reports of detection of the red edge in the spectrum of Earthshine (i.e., the spatially integrated scattered light spectrum of Earth). We present Earthshine observations from Apache Point Observatory (New Mexico) to emphasize that time variability is key to detecting weak surface biosignatures such as the vegetation red edge. We briefly discuss the evolutionary advantages of vegetation's red edge reflectance, and speculate that while extraterrestrial "light-harvesting organisms" have no compelling reason to display the exact same red edge feature as terrestrial vegetation, they might have similar spectroscopic features at different wavelengths than terrestrial vegetation. This implies that future terrestrial-planet-characterizing space missions should obtain data that allow time-varying, sharp spectral features at unknown wavelengths to be identified. We caution that some mineral reflectance edges are similar in slope and strength to vegetation's red edge (albeit at different wavelengths); if an extrasolar planet reflectance edge is detected care must be taken with its interpretation. PMID:15941381

  11. School Environment and School Injuries

    PubMed Central

    Salminen, Simo; Kurenniemi, Marja; Råback, Mirka; Markkula, Jaana; Lounamaa, Anne

    2013-01-01

    Background: Although injuries at school are an important issue in public health, environmental factors in schools and school yards have seldom been the focus of school injury research. The goal of our investigation was to examine the effect of environmental factors on school injuries. Methods: Nine comprehensive Finnish schools registered school injuries over a period of two school years. Injuries were classified as being associated with environmental factors, suspected environmental factors, and others. The consensus between two independent classifiers was 81%. Results: A total of 722 injuries were classified. In 11.6% of these injuries, the physical environment factor was evident, and in 28.1% of the injuries, physical environment was suspected of being a contributory risk factor. Thus the physical environment of the school was a contributing factor in over a third (39.7%) of injuries occurring in the school, on the school yard or during the journey to, or from school. In this study, conducted in Finland, ice on the ground was mentioned most frequently as an environmental risk factor. Conclusion: In Finland, the Nordic weather conditions are not taken into account in the school yard and playground plans as they ought to from the safety point of view. An initiative has been launched on a mandatory wintertime master plan for every school yard. PMID:24455667

  12. Visual edge orientation shapes free-flight behavior in Drosophila.

    PubMed

    Frye, Mark A; Dickinson, Michael H

    2007-01-01

    Insects rely on visual cues to estimate and control their distance to approaching objects and their flight speed. Here we show that in free-flight, the motion cues generated by high-contrast vertical edges are crucial for these estimates. Within a visual environment dominated by high-contrast horizontal edges, flies fly unusually fast and barely avoid colliding with the walls of the enclosure. The disruption of flight behavior by horizontal edges provides insight into the structure of visually-mediated control algorithms.

  13. Wisps in the outer edge of the Keeler Gap

    NASA Astrophysics Data System (ADS)

    Tiscareno, M. S.; Arnault, E. G.

    2014-12-01

    The outer part of Saturn's A ring contains five sharp edges: the inner and outer edges of the Encke Gap and of the Keeler Gap (which contain the moons Pan and Daphnis, respectively), and the outer edge of the A ring itself. Four of these five edges are characterized by structure at moderate to high spatial frequencies, with amplitudes ranging from 2 to 30 km (Tiscareno et al. 2005, DPS). Only the outer edge of the Keeler Gap is reasonably smooth in appearance (Tiscareno et al. 2005, DPS), with occultations indicating residuals less than 1 km upon a possibly non-zero eccentricity (R.G. French, personal communication, 2014). Superposed upon the relatively smooth outer edge of the Keeler Gap are a system of "wisps," which appear to be ring material protruding inward into the gap, usually with a sharp trailing edge and a smooth gradation back to the background edge location on the leading side (Porco et al. 2005, Science). The radial amplitude of wisps is usually 0.5 to 1 km, and their azimuthal extent is approximately a degree of longitude (~2400 km). Wisps are likely caused by an interplay between Daphnis (and perhaps other moons) and embedded moonlets within the ring, though the details remain unclear. We will present a catalogue of wisp detections in Cassini images. We carry out repeated gaussian fits of the radial edge location in order to characterize edge structure (see Figure, which compares our fitted edge to the figure presented by Porco et al. 2005) and visually scan those fitted edges in order to detect wisps. With extensive coverage in longitude and in time, we will report on how wisps evolve and move, both within an orbit period and on longer timescales. We will also report on the frequency and interpretation of wisps that deviate from the standard morphology. We will discuss the implications of our results for the origin and nature of wisps, and for the larger picture of how masses interact within Saturn's rings.

  14. Helical Quantum Edge Gears in 2D Topological Insulators.

    PubMed

    Chou, Yang-Zhi; Levchenko, Alex; Foster, Matthew S

    2015-10-30

    We show that two-terminal transport can measure the Luttinger liquid (LL) parameter K, in helical LLs at the edges of two-dimensional topological insulators (TIs) with Rashba spin-orbit coupling. We consider a Coulomb drag geometry with two coplanar TIs and short-ranged spin-flip interedge scattering. Current injected into one edge loop induces circulation in the second, which floats without leads. In the low-temperature (T→0) perfect drag regime, the conductance is (e^{2}/h)(2K+1)/(K+1). At higher T, we predict a conductivity ~T^{-4K+3}. The conductivity for a single edge is also computed.

  15. Backscattering between helical edge states via dynamic nuclear polarization

    NASA Astrophysics Data System (ADS)

    Del Maestro, Adrian; Hyart, Timo; Rosenow, Bernd

    2013-04-01

    We show that the nonequilibrium spin polarization of one-dimensional helical edge states at the boundary of a two-dimensional topological insulator can dynamically induce a polarization of nuclei via the hyperfine interaction. When combined with a spatially inhomogeneous Rashba coupling, the steady-state polarization of the nuclei produces backscattering between the topologically protected edge states leading to a reduction in the conductance which persists to zero temperature. We study these effects in both short and long edges, uncovering deviations from Ohmic transport at finite temperature and a current noise spectrum which may hold the fingerprints for experimental verification of the backscattering mechanism.

  16. Helical Quantum Edge Gears in 2D Topological Insulators

    NASA Astrophysics Data System (ADS)

    Chou, Yang-Zhi; Levchenko, Alex; Foster, Matthew S.

    2015-10-01

    We show that two-terminal transport can measure the Luttinger liquid (LL) parameter K , in helical LLs at the edges of two-dimensional topological insulators (TIs) with Rashba spin-orbit coupling. We consider a Coulomb drag geometry with two coplanar TIs and short-ranged spin-flip interedge scattering. Current injected into one edge loop induces circulation in the second, which floats without leads. In the low-temperature (T →0 ) perfect drag regime, the conductance is (e2/h )(2 K +1 )/(K +1 ). At higher T , we predict a conductivity ˜T-4 K +3. The conductivity for a single edge is also computed.

  17. Improvement of the edge rotation diagnostic spectrum analysis via simulation

    SciTech Connect

    Luo, J.; Zhuang, G. Cheng, Z. F.; Zhang, X. L.; Hou, S. Y.; Cheng, C.

    2014-11-15

    The edge rotation diagnostic (ERD) system has been developed on the Joint Texas Experimental Tokamak to measure the edge toroidal rotation velocity by observing the shifted wavelength of carbon V (C V 227.09 nm). Since the measured spectrum is an integrated result along the viewing line from the plasma core to the edge, a method via simulation has been developed to analyze the ERD spectrum. With the necessary parameters such as C V radiation profile and the ion temperature profile, a local rotation profile at the normalized minor radius of 0.5-1 is obtained.

  18. Edge state and crisis in the Pierce diode

    SciTech Connect

    Munoz, Pablo R.; Rempel, Erico L.; Chian, Abraham C.-L.

    2012-09-15

    We study the chaotic dynamics of the Pierce diode, a simple spatially extended system for collisionless bounded plasmas, focusing on the concept of edge of chaos, the boundary that separates transient from asymptotic dynamics. We fully characterize an interior crisis at the end of a periodic window, thereby showing direct evidence of the collision between a chaotic attractor, a chaotic saddle, and the edge of chaos, formed by a period-3 unstable periodic orbit and its stable manifold. The edge of chaos persists after the interior crisis, when the global attractor of the system increases its size in the phase space.

  19. Structural Health Monitoring Analysis for the Orbiter Wing Leading Edge

    NASA Technical Reports Server (NTRS)

    Yap, Keng C.

    2010-01-01

    This viewgraph presentation reviews Structural Health Monitoring Analysis for the Orbiter Wing Leading Edge. The Wing Leading Edge Impact Detection System (WLE IDS) and the Impact Analysis Process are also described to monitor WLE debris threats. The contents include: 1) Risk Management via SHM; 2) Hardware Overview; 3) Instrumentation; 4) Sensor Configuration; 5) Debris Hazard Monitoring; 6) Ascent Response Summary; 7) Response Signal; 8) Distribution of Flight Indications; 9) Probabilistic Risk Analysis (PRA); 10) Model Correlation; 11) Impact Tests; 12) Wing Leading Edge Modeling; 13) Ascent Debris PRA Results; and 14) MM/OD PRA Results.

  20. Range and correlation effects in edge disordered graphene nanoribbons

    NASA Astrophysics Data System (ADS)

    Cresti, Alessandro; Roche, Stephan

    2009-09-01

    In this paper, we investigate the impact of edge disorder on the transport properties of graphene nanoribbons with zigzag and armchair symmetries. The diffusive and localization conduction regimes are analysed by performing a mesoscopic study on long disordered ribbons and by extracting elastic mean free paths and localization lengths. At fixed defect density and depending on specific edge disorder profile and ribbon symmetry, we observe strong transport fluctuations resulting in large mobility gaps or robust quasi-ballistic transport. These features are shown to be connected with the topology of edge irregularities as well as their correlation degree. Zigzag nanoribbons are also shown to be more robust than armchairs for similar disorder parameters.