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Sample records for led problem xavier

  1. Encountering Indigeneity: Xavier Herbert, ‘Inky’ Stephensen and the Problems of Settler Nationalism

    Directory of Open Access Journals (Sweden)

    Dan Tout

    2017-11-01

    Full Text Available The 1930s in Australia was a period marked by rising awareness of and attention to Australia’s ‘half-caste problem’. Released and promoted in tandem with the 1938 sesquicentenary of Australia’s settler colonisation, Xavier Herbert’s novel Capricornia appeared as a searing protest against the exclusion of so-called ‘half-castes’ from white Australia. The novel itself was published by the Publicist Publishing Company, platform for rationalist and businessman W.J. Miles and editor and polemicist P.R. ‘Inky’ Stephensen, both strict advocates of a racially pure white Australia. Yet together, Herbert and his patrons capitalised on the sesquicentenary, and the Day of Mourning protests they helped organise, to promote what they proclaimed the ‘Great Australian Novel’. This article reads Herbert’s racial understandings in relation to those of Stephensen, and reads them both in relation to the prevailing circumstances of 1930s Australia, as well as the underlying dynamics of settler colonialism. Whereas Stephensen subscribed to the ‘Aryan Aborigines’ hypothesis and emphasised Australia’s supposed racial purity, Herbert celebrated instead the potentiality of ‘Euraustralian’ hybridity. While these approaches are ostensibly at odds, this article argues instead that they share a common drive towards settler indigenisation and independence as their ultimate aims.

  2. Claustrophilia and Exalted Imagination: Fictional Responses to a Pascalian Problem in the Works of Xavier de Maistre and Jan Potocki

    OpenAIRE

    Haugen, Marius Warholm

    2016-01-01

    This article explores the topics of confinement and claustrophilia in Xavier de Maistre’s Voyage autour de ma chambre (1795) and Expédition nocturne autour de ma chambre (1825), and in Jan Potocki’s Manuscrit trouvé à Saragosse (1791–1814). These works resonate with ideas put forward by Blaise Pascal in the Pensées, more precisely with the reflections on man’s need for constant diversion, represented though the image of his incapacity to stay alone in a room. The fictions of de Maistre and Po...

  3. Xavier Lagrue - 1969-2006

    CERN Document Server

    2006-01-01

    With sadness and consternation we mourn for the death of Xavier who left us suddenly at the age of 37. Xavier is a person to remember, especially for those of us who had worked with him at CERN. Still very young in 1998, he joined CERN's EP-TA2 group to work on the ALICE TPC. He was involved in the conception, preparation and tests of the prototype field cage, and made many original and significant contributions. His youthful enthusiasm that enlightened all of us would not succumb to hardship and setbacks. In 2004 he joined CMS where he soon became an expert in hydraulic and mechanical jacks to move the very large elements of the detector. He participated and managed very severe and complicate maneuvers to close CMS for the first time and made the Magnet and Cosmic Challenge Test a success. He was devoted to a high quality of work with a humble sense of responsibility for his team and project. Xavier was a great asset to our teams, professionally as well as humanly, and a wonderful friend to many of us. He w...

  4. Xavier Herbert. Requiem for Genius

    Directory of Open Access Journals (Sweden)

    Russell McDougall

    2017-11-01

    Full Text Available In today’s global celebrity culture it’s hard to imagine a word more over-used and abused than ‘genius’. It is a slippery word with a long and contradictory conceptual history. Yet, in the Land of the Tall Poppy, self-confessions of genius invariably have paved a broad road to public ridicule and denigration. Xavier Herbert’s notion of genius was not static. It changed throughout his life and it evolved through his writing. He agreed with Carlyle that the first condition of genius must always be a ‘transcendent capacity of taking trouble’ and on this foundation he built his own concept of genius, as the unending ‘capacity for loving’. This article explores what genius meant to Xavier Herbert and how it translated into his fiction, before considering how our sense of genius today influences the way we respond to his most challenging fictions of love and hate, 'Capricornia' and 'Poor Fellow My Country'.

  5. Xavier Herbert: Forgotten or Repressed?

    Directory of Open Access Journals (Sweden)

    Liz Conor

    2017-11-01

    Full Text Available Xavier Herbert is one of Australia’s outstanding novelists and one of the more controversial. In his time, he was also an outspoken public figure. Yet many young Australians today have not heard of the man or his novels. His key works Capricornia (1938 and Poor Fellow My Country (1975 won major awards and were judged as highly significant on publication, yet there has been relatively little analysis of their impact. Although providing much material for Baz Luhrmann’s blockbuster film Australia (2008, his works are rarely recommended as texts in school curricula or in universities. Gough Whitlam took a particular interest in the final draft of Poor Fellow My Country, describing it as a work of ‘national significance’ and ensuring the manuscript was sponsored to final publication. In 1976 Randolph Stow described it as ‘THE Australian classic’. Yet, a search of the Australian Literature database will show that it is one of the most under-read and least taught works in the Australian literary canon. In our view, an examination of his legacy is long overdue. This collection brings together new scholarship that explores the possible reasons for Herbert’s eclipse within public recognition, from his exposure of unpalatable truths such as interracial intimacy, to his relationship with fame. This reevaluation gives new readings of the works of this important if not troublesome public intellectual and author.

  6. Aby-led feeding: problems and consequences in infants

    Directory of Open Access Journals (Sweden)

    K.D. Duka

    2017-03-01

    Full Text Available Background. WHO and UNICEF recommend “to encourage breastfeeding on demand of the child” in the paragraph 8 of Declaration. This is the recommendation for each institution that provides obstetrical services and follow-up of a newborn. But after 5–6 months of breastfeeding on demand it cannot be declared. At the child’s growth all the organs and systems of the kid are forming. And what was natural in the neonatal period may not be mechanically taken against the child of 3 months old. This is caused by special needs of a child for feeding, sleep duration; also it is less time for nap and more for activity in different ages. Therefore, the term free feeding on demand of the child often comes to casuistic when 3–4 month baby gets breastfeeding up to 8–9 times per day on demand. A three-year child who has been on free breastfeeding for a long time (more than 6 months refuses any food, but breast milk. The purpose of the study was to clarify the situation concerning baby-led breastfeeding on demand in infants according to questionnaires. Materials and methods. There were analyzed questionnaires of mothers who have children aged under one year in different areas of the city of Dnipro (n = 248 questionnaires. Results. According to the survey results baby-led breastfeeding until 6 months occurred in 48 % of cases, more than 6 months in 29.6 % of cases, to one year or more in 18.4 %. It is interesting that today late (7 months and older breastfeeding takes place. Often it becomes a chaotic feeding excluding major age-related anatomical and physiological characteristics of the digestive tract that dictate the rules for weaning needs. Conclusions. The researches of the baby-led breastfeeding showed the problems and consequences that accompany it, namely relatively late complementary feeding in infants on free breastfeeding, chaotic feeding without taking into account the basic age needs of infants.

  7. Xavier Vidal-Folch : Loobume rahast teie kasuks / Xavier Vidal-Folch ; interv. Marianne Mikko

    Index Scriptorium Estoniae

    Vidal-Folch, Xavier

    2003-01-01

    Hispaania juhtiva ajalehe El Pais asedirektor Xavier Vidal-Folch Eesti astumisest Euroopa Liitu ja NATO-sse. Meenutusi Hispaania liitumisest EL-iga, Euroopa solidaarsusest, EL-i põhiseaduslikust lepingust

  8. Xavier Mina en los Estados Unidos (1816)

    OpenAIRE

    Ortuño Martínez, Manuel

    1999-01-01

    A very interesting fact related to the Spanish American rebellions against the mother country took place during the second decade of the XIX century. The protagonist was Xavier Mina, a young liberal soldier ignored by the Spanish historiography. American scholars like Harris G. Warren and Stanley Faye published the results of his researches many years ago. With the support of the Spanish liberal exiles and Spanish American living in London, Mina organized an intemational expedition that...

  9. Developing Breast Cancer Program at Xavier; Genomic and Proteomic Analysis of Signaling Pathways Involved in Xenohormone and MEK5 Regulation of Breast Cancer

    National Research Council Canada - National Science Library

    Wiese, Thomas E

    2006-01-01

    Xavier University (XU) and the Tulane Cancer Center (TCC) will build a core of human talent that will address scientific problems such as drug resistance and the effect of environmental agents on breast cancer (BC...

  10. Developing Breast Cancer Program at Xavier: Genomic and Proteomic Analysis of Signaling Pathways Involved in Xenohormone and MEK5 Regulation of Breast Cancer

    National Research Council Canada - National Science Library

    Wiese, Thomas E

    2005-01-01

    Xavier University (XU) and the Tulane Cancer Center (TCC) will build a core of human talent that will address scientific problems such as drug resistance and the effect of environmental agents on breast cancer (BC...

  11. Developing Breast Cancer Program at Xavier; Genomic and Proteomic Analysis of Signaling Pathways Involved in Xenohormone and MEK5 Regulation of Breast Cancer

    National Research Council Canada - National Science Library

    Wiese, Thomas E

    2007-01-01

    Xavier University (XU) and the Tulane Cancer Center (TCC) will build a core of human talent that will address scientific problems such as drug resistance and the effect of environmental agents on breast cancer (BC...

  12. Xavier Zubiri e il problema della verità ‘attuale’

    Directory of Open Access Journals (Sweden)

    Ponzio, Paolo

    2016-08-01

    Full Text Available This article aims to investigate the problem of truth in the thinking of Xavier Zubiri, from its beginnings. For this reason, even if the goal is to explore the concept of truth in his last declination, i.e., in the trilogy of sentient intelligence (1980-1983, previous essays by the philosopher must not be ignored when assessing his originality with respect to Twentieth century philosophy.El presente artículo quiere indagar el problema de la verdad en el pensamiento de Xavier Zubiri, desde sus inicios. Por esta razón, incluso si el objetivo es explorar el concepto de verdad en su última declinación, es decir, dentro de la trilogía de la inteligencia sentiente (1980-1983, no se puede ignorar los ensayos anteriores del filósofo, para evaluar plenamente la originalidad de su pensamiento con respecto a la filosofía del siglo XX.

  13. 75 FR 22412 - Food and Drug Administration/Xavier University Global Outsourcing Conference

    Science.gov (United States)

    2010-04-28

    ...] Food and Drug Administration/Xavier University Global Outsourcing Conference AGENCY: Food and Drug... ``FDA/Xavier University Global Outsourcing Conference.'' This 3-day public conference for the.... The conference will focus on global compliance challenges associated with pharmaceutical outsourcing...

  14. Peer-led problem-based learning in interprofessional education of health professions students

    Directory of Open Access Journals (Sweden)

    Michael D. Lehrer

    2015-09-01

    Full Text Available Background: The role of peer teachers in interprofessional education has not been extensively studied. This study is designed to determine if peer-teacher-led problem-based seminars can influence medical and pharmacy students’ perceptions of interprofessional education. Methods: Undergraduate medical and pharmacy students participated in one-hour problem-based learning seminars held over the course of 16 weeks. A case–control study design was used to compare perceptions of interprofessional education between students who participated in seminars and students who did not participate in seminars. The validated Interdisciplinary Education Perception Scale (IEPS was used to assess perceptions of interprofessional education and was distributed to medical and pharmacy students at the conclusion of 16 weeks of seminars. A two-tailed t-test was used to determine significance between groups. A survey was also distributed to all students regarding perceived barriers to involvement in interprofessional education training. Results: In total, 97 students responded to IEPS (62 medical, 35 pharmacy. Data showed significantly higher perception of professional cooperation among medical students (p=0.006 and pharmacy students (p=0.02 who attended interprofessional seminars compared to those who did not attend. One hundred and nine students responded to the survey regarding perceived barriers to interprofessional education, with the two most common barriers being: ‘I am not aware of interprofessional education opportunities’ (61.5% and ‘I do not have time to participate’ (52.3%. Conclusion: Based on this data we believe peer-teacher-led problem-based interprofessional seminars can be used to increase medical and pharmacy students’ perceived need for professional cooperation. Currently, major barriers to interprofessional education involvement are awareness and time commitment. Undergraduate health professions education can incorporate student-led

  15. Peer-led problem-based learning in interprofessional education of health professions students.

    Science.gov (United States)

    Lehrer, Michael D; Murray, Samuel; Benzar, Ruth; Stormont, Ryan; Lightfoot, Megan; Hafertepe, Michael; Welch, Gabrielle; Peters, Nicholas; Maio, Anna

    2015-01-01

    The role of peer teachers in interprofessional education has not been extensively studied. This study is designed to determine if peer-teacher-led problem-based seminars can influence medical and pharmacy students' perceptions of interprofessional education. Undergraduate medical and pharmacy students participated in one-hour problem-based learning seminars held over the course of 16 weeks. A case-control study design was used to compare perceptions of interprofessional education between students who participated in seminars and students who did not participate in seminars. The validated Interdisciplinary Education Perception Scale (IEPS) was used to assess perceptions of interprofessional education and was distributed to medical and pharmacy students at the conclusion of 16 weeks of seminars. A two-tailed t-test was used to determine significance between groups. A survey was also distributed to all students regarding perceived barriers to involvement in interprofessional education training. In total, 97 students responded to IEPS (62 medical, 35 pharmacy). Data showed significantly higher perception of professional cooperation among medical students (p=0.006) and pharmacy students (p=0.02) who attended interprofessional seminars compared to those who did not attend. One hundred and nine students responded to the survey regarding perceived barriers to interprofessional education, with the two most common barriers being: 'I am not aware of interprofessional education opportunities' (61.5%) and 'I do not have time to participate' (52.3%). Based on this data we believe peer-teacher-led problem-based interprofessional seminars can be used to increase medical and pharmacy students' perceived need for professional cooperation. Currently, major barriers to interprofessional education involvement are awareness and time commitment. Undergraduate health professions education can incorporate student-led seminars to improve interprofessional education.

  16. Comparative analysis of different cooling fin types for countering LED luminaires' heat problems

    OpenAIRE

    KARATEKİN, CANAN; KÖKKAYA, OYTUN

    2018-01-01

    A significant problem with high-power LED luminaires is heat. Aluminum heat sinks have been extensively used as a solution. The most common method for heat sinks that increases surface area uses fins. In the present study, pin- and plate-fins were compared and it was observed that, in equal surface areas, better cooling was achieved by pin-fins. Thus, the study's concentration narrowed to pin-fins and the results of different pin-fins were compared. Simulations of a sample group were...

  17. Student-led tutorials in problem-based learning: educational outcomes and students' perceptions.

    Science.gov (United States)

    Kassab, Salah; Abu-Hijleh, Marwan F; Al-Shboul, Qasim; Hamdy, Hossam

    2005-09-01

    The aim of this study was to examine the effectiveness of using students as tutors in a problem-based learning (PBL) medical curriculum. Ninety-one third-year medical students were divided into ten tutorial groups. The groups were randomly allocated into student-led tutorials (SLT) (five groups, n = 44 students) and faculty-led tutorials (FLT) (five groups, n = 47 students). Outcome measurements included assessment of students' performance in tutorials individually and as a group, end-unit examinations scores, assessment of tutoring skills and identifying students' perceptions about peer tutoring. Student tutors were perceived better in providing feedback and in understanding the difficulties students face in tutorials. Tutorial atmosphere, decision-making and support for the group leader were better in SLT compared with FLT groups. Self-assessment of student performance in SLT was not different from FLT. Student scores in the written and practical examinations were comparable in both groups. However, SLT groups found difficulties in analysis of problems presented in the first tutorial session. We conclude that the impact of peer tutoring on student performance in tutorials, group dynamics, and student achievement in examinations is positive overall. However, student tutors require special training before adopting this approach in PBL programs.

  18. Remapping Capricornia: Xavier Herbert’s Cosmopolitan Imagination

    OpenAIRE

    Ellen Smith

    2017-01-01

    Since its publication in 1938 critics have generally read Xavier Herbert’s Capricornia as a nationalist novel, even when its nationalism is seen to be structured by contradiction. But little attention has been given to the ways in which Herbert’s complex, multifarious and heteroglossic novel exceeds and challenges the very possibility of coherent national space and a coherent national story. This essay considers moments and spaces in Herbert’s novel where the national is displaced and unravel...

  19. The Queer Voices of Xavier Dolan’s Mommy

    OpenAIRE

    D’Aoust, Jason R.

    2017-01-01

    This article examines the vocal materialities of Xavier Dolan’s film Mommy (2014). It focuses on the film’s swearing, competing diegetic voices, disruptive soundtrack, as well as its scenes of lip synch, play-back, and karaoke, in order to convey queer vocal identifications. The article’s interdisciplinary methodology includes audiovisual theories of the voice-object, post-Lacanian psychoanalysis, and revisions of the voice’s place in queer theories via critiques of videocentrism.

  20. 76 FR 15986 - Food and Drug Administration/Xavier University Global Medical Device Conference

    Science.gov (United States)

    2011-03-22

    ...] Food and Drug Administration/Xavier University Global Medical Device Conference AGENCY: Food and Drug... ``FDA/Xavier University Global Medical Device Conference.'' This 3-day public conference includes.... Combination Products Panel. Update on Quality System Regulations. Warning Letter and Enforcement Action Trends...

  1. En torno a la realidad humana en Xavier Zubiri

    Directory of Open Access Journals (Sweden)

    Espinoza Lolas, Ricardo

    2016-08-01

    Full Text Available This article inquires into the nature of human reality and its connection to the concept of person in the philosophy of Xavier Zubiri(1898-1983. The methodology of the analysis consists in reviewing the nature of human reality through the prism of noology, i.e., the final period of this author’s work, in order to introduce man from its always incarnate, prominently physical, dimension of human reality. This allows individual development and the historical and social display of the human being from a physical perspective to be represented.Este artículo indaga acerca del carácter de la realidad humana y su relación al concepto de persona en el pensamiento de Xavier Zubiri (1898-1983. La metodología de análisis consiste en revisar el carácter de la realidad humana desde la noología, esto es, la última etapa de la obra del autor, a fin de presentar al hombre desde su dimensión eminentemente física y siempre encarnada de la realidad humana, permitiendo repensar desde una perspectiva física el desarrollo individual, así como también, el despliegue social e histórico del ser humano.

  2. Symptoms Versus Problems (SVP Framework on Export Barriers to SME’S Led Electronic Products in Taiwan

    Directory of Open Access Journals (Sweden)

    Kader Ali Noor N.

    2016-01-01

    Full Text Available Export barriers are a common constraints to SMEs when exporting goods. In 2013, Taiwan’s export sales dropped by 18.5% due to SMEs’ difficulty to explore the overseas market, thus, redirect their sales locally. The objective of this case study is to identify the internal and external barriers, and the export model practiced by one export case in Taipei, Taiwan. Findings via semi-structured interviews, field observation and analysis of unpublished company data are summarized using a new root-cause analysis tool called Symptoms versus Problems (SVP framework for SME LED Exports. The new SVP framework discovers many symptoms leading to recognition of six major problems, namely, high operational cost, poor marketing strategy, lack of cash flow funds, talent and skill sets, government support, and too many foreign bureaucracy regulations. These problems are categorized into three groups, namely, operation, marketing and government bureaucracies. The recommendations for each problem are structured to improve product costs, branding and advertisement strategies, cash flow management, technical know-how of foreign market behaviour, sources of information and network, and managing the foreign bureaucracies. Interestingly, this study discovers another new framework that overcome LED export barriers called “House of Pillars for LED Exports” in Taiwan.

  3. YouTube Fridays: Student Led Development of Engineering Estimate Problems

    Science.gov (United States)

    Liberatore, Matthew W.; Vestal, Charles R.; Herring, Andrew M.

    2012-01-01

    YouTube Fridays devotes a small fraction of class time to student-selected videos related to the course topic, e.g., thermodynamics. The students then write and solve a homework-like problem based on the events in the video. Three recent pilots involving over 300 students have developed a database of videos and questions that reinforce important…

  4. Tulane/Xavier University hazardous materials in aquatic environments of the Mississippi River Basin. Annual technical report, January 1--December 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-02

    Tulane and Xavier Universities have singled out the environment as a major strategic focus for research and training for now and beyond the year 2000. In 1989, the Tulane/Xavier Center for Bioenvironmental Research (CBR) was established as the umbrella organization which coordinates environmental research at both universities. In December, 1992, the Tulane/Xavier CBR was awarded a five year grant to study pollution in the Mississippi River system. The Hazardous Materials in Aquatic Environments of the Mississippi River Basin project is a broad research and education program aimed at elucidating the nature and magnitude of toxic materials that contaminate aquatic environments of the Mississippi River Basin. Studies include defining the complex interactions that occur during the transport of contaminants, the actual and potential impact on ecological systems and health, and the mechanisms through which these impacts might be remediated. The Mississippi River Basin represents a model system for analyzing and solving contamination problems that are found in aquatic systems world-wide. Summaries which describe objectives, goals, and accomplishments are included on ten collaborative cluster projects, two education projects, and six initiation projects. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  5. Remapping Capricornia: Xavier Herbert’s Cosmopolitan Imagination

    Directory of Open Access Journals (Sweden)

    Ellen Smith

    2017-11-01

    Full Text Available Since its publication in 1938 critics have generally read Xavier Herbert’s Capricornia as a nationalist novel, even when its nationalism is seen to be structured by contradiction. But little attention has been given to the ways in which Herbert’s complex, multifarious and heteroglossic novel exceeds and challenges the very possibility of coherent national space and a coherent national story. This essay considers moments and spaces in Herbert’s novel where the national is displaced and unravelled. Drawing on Rebecca Walkowitz’s idea of cosmopolitan style and Suvendrini Perera’s work on Australia’s insular imagination I identify a critical cosmopolitanism that inheres in the novel’s geographical imagination and its literary form, particularly the narrative voice which retains a critical distance from the nationalist sensibility of various characters and plot lines, performing a detached and restless homelessness that I identify with the cosmopolitan. Ultimately I ask how the novel’s spatial and environmental imagination displaces its nationalist agenda, making space for a different kind of social imagination—one that does not confine itself to the terms of the nation or organise itself around a central figure for the nation.

  6. Xavier's Take on Authentic Writing: Structuring Choices for Expression and Impact

    Science.gov (United States)

    Behizadeh, Nadia

    2015-01-01

    Because authenticity in education is a subjective judgment regarding the meaningfulness of an activity, a need exists to co-investigate with students classroom factors increasing authenticity of writing. In this case study, one 8th grade student's needs for authentic writing are explored in detail. Xavier's take on authentic writing…

  7. Saint Francis Xavier on Jesuit School Stages of the Bohemian Province

    Czech Academy of Sciences Publication Activity Database

    Bobková, Kateřina; Jacková, Magdaléna

    2015-01-01

    Roč. 25, č. 2 (2015), s. 135-155 ISSN 0515-3190 R&D Projects: GA ČR GPP406/12/P823 Institutional support: RVO:68378068 ; RVO:67985963 Keywords : St. Francis Xavier * Jesuit saints * Jesuit theatre * neolatin drama * school theatre * Avancini, Nicolaus * Engel, Arnoldus Subject RIV: AJ - Letters, Mass-media, Audiovision; AB - History (HIU-Y)

  8. Tulane/Xavier Center for Bioenvironmental Research; project: hazardous materials in aquatic environments; subproject: biomarkers and risk assessment in Bayou Trepagnier, LA

    International Nuclear Information System (INIS)

    Ide, C.

    1996-01-01

    Tulane and Xavier Universities have singled out the environment as a major strategic focus for research and training for now and beyond the year 2000. the Tulane/Xavier Center for Bioenvironmental Research (CBR) was established in 1989 as the umbrella organization to coordinate environmental research at both universities. CBR projects funded by the DOE under the Hazardous Materials in Aquatic Environments grant are defining the following: (1) the complex interactions that occur during the transport of contaminants through wetlands environments, (2) the actual and potential impact of contaminants on ecological systems and health, (3) the mechanisms and new technologies through which these impacts might be remediated, and (4) new programs aimed at educating and training environmental workers of the future. The subproject described in this report, 'Biomarkers and Risk Assessment in Bayou Trepagnier, LN', is particularly relevant to the US Department of Energy's Environmental Restoration and Waste Management program aimed at solving problems related to hazard monitoring and clean-up prioritization at sites with aquatic pollution problems in the DOE complex

  9. Building integrated pathways to independence for diverse biomedical researchers: Project Pathways, the BUILD program at Xavier University of Louisiana.

    Science.gov (United States)

    Foroozesh, Maryam; Giguette, Marguerite; Morgan, Kathleen; Johanson, Kelly; D'Amour, Gene; Coston, Tiera; Wilkins-Green, Clair

    2017-01-01

    Xavier University of Louisiana is a historically Black and Catholic university that is nationally recognized for its science, technology, engineering and mathematics (STEM) curricula. Approximately 73% of Xavier's students are African American, and about 77% major in the biomedical sciences. Xavier is a national leader in the number of STEM majors who go on to receive M.D. degrees and Ph.D. degrees in science and engineering. Despite Xavier's advances in this area, African Americans still earn about 7.5% of the Bachelor's degrees, less than 8% of the Master's degrees, and less than 5% of the doctoral degrees conferred in STEM disciplines in the United States. Additionally, although many well-prepared, highly-motivated students are attracted by Xavier's reputation in the sciences, many of these students, though bright and capable, come from underperforming public school systems and receive substandard preparation in STEM disciplines. The purpose of this article is to describe how Xavier works to overcome unequal education backgrounds and socioeconomic challenges to develop student talent through expanding biomedical training opportunities and build on an established reputation in science education. The National Institutes of Health (NIH)/National Institute of General Medical Sciences (NIGMS)-funded BUILD (Building Infrastructure Leading to Diversity) Program at Xavier University of Louisiana, Project Pathways , is a highly-innovative program designed to broaden the career interests of students early on, and to engage them in activities that entice them to continue their education towards biomedical research careers. Project strategies involve a transformation of Xavier's academic and non-academic programs through the redesign, supplementation and integration of academic advising, tutoring, career services, personal counseling, undergraduate research training, faculty research mentoring, and development of new biomedical and research skills courses. The Program also

  10. Una lucha a "cielo abierto" : el caso del Frente Amplio Opositor a Minera San Xavier

    OpenAIRE

    Lamberti, María Julieta

    2010-01-01

    Se presenta un estudio de caso de un conflicto ecológico distributivo por la instalación de una empresa minera de tajo a cielo abierto desde la perspectiva de uno de los actores involucrados, el Frente Amplio Opositor a Minera San Xavier en Cerro de San Pedro, San Luis Potosí. Para dar cuenta del sentido que le otorgan los miembros del FAO a la instalación de la empresa en la comunidad se utilizan los procesos de enmarcado como herramienta de interpretación. I. La interpretación de los con...

  11. El ritmo de intensidad en La rosa escrita de Xavier Abril

    Directory of Open Access Journals (Sweden)

    Óscar Coello

    2011-07-01

    Full Text Available Luego de las aventuras rítmicas practicadas por Abril en las más audaces posiciones de vanguardia, se produce una abjuración insólita –explicada luego metatextualmente– en la poiesis del artista, que lo regresa a los cauces de la elaboración versal tradicional. La rosa escrita es el poemario más emblemático de este retorno. La presente ponencia ejemplifica en un texto, a través del ritmo de intensidad, los pormenores de esta redención.Palabras claves: Xavier Abril, La rosa escrita, Vanguardia, ritmo.

  12. Effects of high-fidelity patient simulation led clinical reasoning course: Focused on nursing core competencies, problem solving, and academic self-efficacy.

    Science.gov (United States)

    Lee, JuHee; Lee, Yoonju; Lee, Senah; Bae, Juyeon

    2016-01-01

    To examine the effects of high-fidelity patient simulation (HFPS) led clinical reasoning course among undergraduate nursing students. A quasi-experimental study of non-equivalent control group pretest-post test design was applied. A total of 49 senior nursing students participated in this study. The experimental group consisted of the students who took the "clinical reasoning" course (n = 23) while the control group consisted of students who did not (n = 26). Self-administered scales including the nursing core competencies, problem solving, academic self-efficacy, and Kolb learning style inventory were analyzed quantitatively using SPSS version 20.0. Data analysis was conducted using one-way ancova due to a significant difference in nursing core competencies between the experimental group and control group. There was a significant improvement in nursing core competencies in the experimental group (F = 7.747, P = 0.008). The scores of problem solving and academic self-efficacy were higher in the experimental group after the HFPS led clinical reasoning course without statistical difference. There is a need for the development of effective instructional methods to improve learning outcomes in nursing education. Future research is needed related to simulation education as well as management strategies so that learning outcomes can be achieved within different students' learning style. © 2015 The Authors. Japan Journal of Nursing Science © 2015 Japan Academy of Nursing Science.

  13. LED lamp

    Science.gov (United States)

    Galvez, Miguel; Grossman, Kenneth; Betts, David

    2013-11-12

    There is herein described a lamp for providing white light comprising a plurality of light sources positioned on a substrate. Each of said light sources comprises a blue light emitting diode (LED) and a dome that substantially covers said LED. A first portion of said blue light from said LEDs is transmitted through said domes and a second portion of said blue light is converted into a red light by a first phosphor contained in said domes. A cover is disposed over all of said light sources that transmits at least a portion of said red and blue light emitted by said light sources. The cover contains a second phosphor that emits a yellow light in response to said blue light. The red, blue and yellow light combining to form the white light and the white light having a color rendering index (CRI) of at least about 80.

  14. (No Laughing Matter: Modernism and Xavier Nogués’ Cartoons

    Directory of Open Access Journals (Sweden)

    Farré Torras, Begoña

    2016-07-01

    Full Text Available This paper discusses the notion of modernism by relating it to three artistic movements – Modernisme, Noucentisme and the Avant-garde – which developed in Catalonia between the 1880s and the early 1920s. From a common commitment to modernity these three movements produced, nonetheless, widely different aesthetic proposals. Notwithstanding their differences, this paper identifies common features in their artistic practices in order to contribute to the ongoing critical review of modernism. Thus, rather than a self-referential, medium-specific quest with abstraction as a natural endpoint, modernism is presented here as an open, interrogative artistic practice engaged in a debate in pursuit of ‘the modern’. This understanding of modernism is then tested against the case of Xavier Nogués, an artist associated with Noucentisme, and his contribution to the artistic debate of his time through the necessarily figurative language of caricature.

  15. Quality attributes of LED lighting. Current state-of-the-art , advantages, problem areas and potential for development - Final report; Qualitaetsmerkmale der LED-Beleuchtung. Aktueller Stand der Technik, Vorteile, Problempunkte und Entwicklungspotential - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Gasser, S.

    2009-09-15

    The present report describes the state-of-the-art of LED technology for room lighting in June 2009, based on internet research, expert interviews as well as a workshop with experts. Of the 20 attributes determined, three key quality characteristics crucial for the breakthrough of LED technology were identified: (i) Energy efficiency: with values of 50 - 70 lumen/watt when in usage, current LED lamps on the market are comparable to energy saving lamps. Experts expect the luminous efficiency to double within the next five years. Declaration is often poor: instead of efficiency in real-life usage many producers declare unrealistic lab measurement results; sometimes even fantasy values are declared. (ii) Light quality: Today's good LEDs reach colour rendering attributes which are comparable to those of halogen lamps and usually better than the CFL's (colour rendering index 80 to 90, with a continuous light spectrum). (iii) Lamp life: A lamp life of up to 50,000 hours can only be reached if the heat dissipation is secured and if the Control gears quality keeps up with the LED's life time. According to the experts, many of today's LED products on the market don't meet these two requirements. Strong uncertainty is caused by inconsistent declaration and partly missing standardisation. With the ANSI standard, the US is ahead of Europe in this matter. Today LED lighting is attractive and economic where its unique advantages can be applied: directional light, very long life-span, no heat in the luminous flux, UV-free light, colour modulation, dimming with little losses. Interesting applications today include: (i) Professional field: operating time > 3,000 hours per year, e.g. shop illumination or downlights in a hall (hotel, administration, etc.). Further spotlights in museums, working place table light fixtures, hybrid solutions (e.g. indirect fluorescent lamp, direct LED). (ii) Domestic field: working place and reading lamps (low luminance, no heat

  16. ‘Little Gunshots, but with the blaze of lightning’: Xavier Herbert, Visuality and Human Rights

    Directory of Open Access Journals (Sweden)

    Jane Lydon

    2017-11-01

    Full Text Available Xavier Herbert published his bestseller Capricornia in 1938, following two periods spent in the Northern Territory. His next major work, Poor Fellow My Country (1975, was not published until thirty-seven years later, but was also set in the north during the 1930s. One significant difference between the two novels is that by 1975 photo-journalism had become a significant force for influencing public opinion and reforming Aboriginal policy. Herbert’s novel, centring upon Prindy as vulnerable Aboriginal child, marks a sea change in perceptions of Aboriginal people and their place in Australian society, and a radical shift toward use of photography as a means of revealing the violation of human rights after World War II. In this article I review Herbert’s visual narrative strategies in the context of debates about this key historical shift and the growing impact of photography in human rights campaigns. I argue that Poor Fellow My Country should be seen as a textual re-enactment, set in Herbert’s and the nation’s past, yet coloured by more recent social changes that were facilitated and communicated through the camera’s lens. Like all re-enactments, it is written in the past conditional: it asks, what if things had been different? It poses a profound challenge to the state project of scientific modernity that was the Northern Territory over the first decades of the twentieth century.

  17. Blood Call and ‘Natural Flutters’: Xavier Herbert’s Racialised Quartet of Heteronormativity

    Directory of Open Access Journals (Sweden)

    Liz Conor

    2017-11-01

    Full Text Available National belonging for Xavier Herbert was intimately tied to interracial sexuality. ‘Euraustralians’ (‘half-castes’ were for Herbert a redemptive motif that could assuage the ‘awful loneliness of the colonial born’ by which he hinted at the land claim of settler-colonials as spurious. Herbert’s exposure of the spectrum of interracial sex—from companionate marriage to casual prostitution to endemic sexual assault—in his novels Capricornia (1938 and Poor Fellow My Country (1975 was unprecedented and potentially game-changing in the administration of Aboriginal women’s sexuality under the assimilation era. But his deeply fraught masculinity was expressed through a picaresque frontier manhood that expressed itself through this spectrum of relations with Aboriginal women. For all his radical assertions of a ‘Euraustralian’ or hybrid nation, Herbert was myopic and dismissive of the women attached to the ‘lean loins’ he hoped it would spring from. He was also vitriolic about the white women, including wives, who interfered with white men’s access to Aboriginal women’s bodies. In this article I examine how Herbert’s utopian racial destinies depended on the unexamined sexual contract of monogamy and the asymmetrical pact to which it consigned white men and white women, and the class of sexually available Indigenous women, or ‘black velvet’, it rested on in colonial scenarios of sex.

  18. Chico Xavier: de bem simbólico do Espiritismo ao panteão da Umbanda. Literatura umbandista e identidade religiosa

    Directory of Open Access Journals (Sweden)

    Artur Cesar Isaia

    2016-01-01

    Full Text Available O objetivo deste texto é mostrar a forma inclusiva como Chico Xavier passa a frequentar a literatura umbandista, chegando ao seu panteão. Mostra o caráter dinâmico e plástico com que a Umbanda constrói-se, sendo capaz de incluir entre as entidades do seu culto, mesmo um bem simbólico do Espiritismo, ciosamente guardado como uma marca identitária espírita brasileira. Sobretudo, evidencia o texto a presença interdiscursiva de Chico Xavier na literatura produzida pelos intelectuais da Umbanda.

  19. Developing an Instrument to Characterise Peer-Led Groups in Collaborative Learning Environments: Assessing Problem-Solving Approach and Group Interaction

    Science.gov (United States)

    Pazos, Pilar; Micari, Marina; Light, Gregory

    2010-01-01

    Collaborative learning is being used extensively by educators at all levels. Peer-led team learning in a version of collaborative learning that has shown consistent success in science, technology, engineering and mathematics disciplines. Using a multi-phase research study we describe the development of an observation instrument that can be used to…

  20. CERN Library and Art@CMS present Artist and Painter Xavier Cortada and CMS Physicist Pete Markowitz

    CERN Multimedia

    CERN Library

    2013-01-01

    Xavier Cortada is an American artist and painter, and an artist in residence at Florida International University (FIU) College of Architecture and the Arts who also specializes in participatory art projects. His work includes art installations at the Earth’s poles to generate awareness about climate change, child welfare murals in Bolivia and peace murals in Cyprus. Xavier will be in conversation with CMS physicist Pete Markowitz, also from FIU, to discuss the participatory art piece which they developed together. The piece will be showcased in the CMS detector hall on Thursday 11 April during the experiment’s conference week. The piece promises to "engage 300 scientists from around the world in a performance art piece that transforms them into the very subatomic particles they research". It is the first piece by Art@CMS, a new project inspired by the Arts@CERN programme. Discover more about how this new piece was developed and more about Xavier’s ...

  1. Light pipes for LED measurements

    Science.gov (United States)

    Floyd, S. R.; Thomas, E. F., Jr.

    1976-01-01

    Light pipe directly couples LED optical output to single detector. Small area detector measures total optical output of diode. Technique eliminates thermal measurement problems and channels optical output to remote detector.

  2. Woman in the Making: The Impact of the Constructed Campus Environment of Xavier University of Louisiana on the Construction of Black Womanhood

    Science.gov (United States)

    Njoku, Nadrea R.

    2017-01-01

    This study explores the experiences of African American women as students at Xavier University of Louisiana (XULA). This study specifically focuses on how these women's experiences at their HBCU facilitated their construction of Black womanhood. This study did not aim to compare, contrast, or situate the experiences of African American women…

  3. Transformaciones del modelo Neogranadino de parroquialización. El caso de la Parroquia San Francisco Xavier de Piedecuesta

    Directory of Open Access Journals (Sweden)

    Luis Rubén Pérez Pinzón

    2013-01-01

    Full Text Available El artículo analiza los fundamentos canónigos, las razones virreinales y los rituales eclesiásticos que justificaron las fundaciones parroquiales del siglo XVIII. Para ello se enfatiza en el modelo de urbanismo de las autoridades borbónicas que sustituyó la práctica de fundaciones de ciudades y villas de los siglos XVI y XVII a partir de capitulaciones. Modelo de necesidades demostradas, visitas a las instituciones virreinales y verificación de méritos que se puede comprobar desde el caso de la parroquia moderna de San Francisco Xavier del Pie de la Cuesta (Santander, Colombia, la cual pasó de ser un sitio irregular a la próspera Villa de San Carlos del siglo XIX.

  4. The inventory of botanical curiosities in Pierre-François-Xavier de Charlevoix's Nouvelle France (1744).

    Science.gov (United States)

    Kobelinski, Michel

    2013-03-01

    The article explores the botanical contributions of Pierre-François-Xavier de Charlevoix's book Histoire et description générale de la Nouvelle France vis-à-vis the contributions of previous researchers, his use of iconographic and discursive representations and its relevance to the project of French colonization. It investigates why he refused Linnaeus' taxonomic model and what he intended with his catalogue of botanical curiosities. The unfolding of his philosophical and religious trajectory allows to understand his stance regarding the classification of nature, the meanings of ethnological information, his forms of intellectual appropriation, and his use of discourse and botanical iconography as political and emotional propaganda to encourage colonial settlement.

  5. La batalla por San Luis: ¿el agua o el oro? La disputa argumentativa contra la Minera San Xavier

    Directory of Open Access Journals (Sweden)

    Pedro Reygadas

    2008-01-01

    Full Text Available El presente artículo se refiere al conflicto urbano socioambiental entre la sociedad civil de San Luis Potosí y la Minera San Xavier en Cerro de San Pedro (1995-2007. Se aplica la metodología descriptiva del análisis discursivo argumentativo a las diversas esquematizaciones de los actores en torno al "patrimonio", el "agua" y el "cianuro", para contribuir a revelar la topología de las posiciones encontradas, delinear los núcleos de sus representaciones, y comprenderlas como parte sustantiva de la confrontación en un proceso político urbano que articula lo local, lo nacional y lo internacional.

  6. Dosimetry in occupational exposure workers of the medical institutes of the University San Francisco Xavier de Chuquisaca; Dosimetria en TOEs de los institutos medicos de la Universidad San Francisco Xavier de Chuquisaca

    Energy Technology Data Exchange (ETDEWEB)

    Zambrana Z, A. J.; Castro S, O.; Huanca S, E.; Torrez C, M. [Universidad Mayor, Real y Pontificia de San Francisco Xavier de Chuquisaca, Instituto de Medicina Nuclear de Sucre, Plaza Libertad No. 1, Sucre (Bolivia, Plurinational State of); Villca Q, I., E-mail: nuclear_sre@entelnet.bo [Universidad Mayor, Real y Pontificia de San Francisco Xavier de Chuquisaca, Instituto Nacional de Cancerologia Dr. Jose Cupertino Arteaga, Plaza Libertad No. 1, Sucre (Bolivia, Plurinational State of)

    2014-08-15

    In this work is made a retrospective analysis of the record, of the dosimetric control readings processed by the Dosimetry Laboratory of the Instituto Boliviano de Ciencia y Tecnologia Nuclear, as regulator entity at national level for Occupational Exposed Workers (OEWs) to ionizing radiations, of the Medical Institutes of the Universidad Mayor, Real y Pontificia de San Francisco Xavier de Chuquisaca, by a period of 10 and 15 years. The results showed that in the Nuclear Medicine Institute of Sucre, the Accumulated Occupational Exposure of a total of 393 readings of 15 OEWs was of 20.4 mSv, identifying as maximum value 10.2 mSv, in the official that develops the Radio-pharmacy activities (elution, fractionation, preparation and management). In the Instituto Nacional de Cancerologia Dr. Jose Cupertino Arteaga the dosimetric background registered an Accumulated Occupational Exposure of a total of 1319 readings of 50 OEWs of 309.69 mSv, with a maximum value of 62.30 mSv, corresponding to the worker of the technical area (maintenance, adjustment and calibration). Comparison that allows to infer that the difference is due mainly to the radio-active source type {sup 99m}Tc Vs {sup 60}Co utilized in these health centers. (Author)

  7. LED-roulette : LED's vervangen balletje

    NARCIS (Netherlands)

    Goossens, P.

    2007-01-01

    Iedereen waagt wel eens een gokje, in een loterij of misschien ook in een casino. Wie droomt er immers niet van om op een gemakkelijke manier rijk te worden? Met de hier beschreven LED-roulette valt weliswaar weinig te winnen, maar het is wel een uitstekende manier om het roulettespel thuis te

  8. Certolizumab, an anti-TNF safe during pregancy? The CRIB Study results: an interview with Professor Xavier Mariette.

    Science.gov (United States)

    Mariette, Xavier

    2017-09-01

    Professor Xavier Mariette, MD, PhD, has served as the Head of the Rheumatology Department of Bicêtre Hospital, Paris-Sud University since 1999, a role he took following 10 years of practice of clinical immunology. Professor Mariette has initiated a number of clinical research studies on biotherapies in autoimmune diseases. He is the head of the French RATIO (Research Axed on Tolerance of Biotherapy) observatory, collecting specific rare serious adverse events in patients treated with anti-TNF. He initiated the French AIR (Autoimmunity and Rituximab) and ORA (Orencia and Rheumatoid arthritis) registries of patients with autoimmune diseases treated with rituximab and abatacept. He initiated clinical trials in Sjögren's syndrome with infliximab, hydroxychloroquine and belimumab. Professor Mariette is involved in basic research, leading a group working on pathogeny of Sjögren's syndrome, relationships between innate immunity and B-cell activation in autoimmunity and the relationships between autoimmunity and lymphoma. Professor Mariette is also very interested in new ways of teaching. In 2007, he participated with other European Experts in the creation of the EULAR Web Course of Rheumatology in 2007. Professor Mariette has been the President of the Scientific Committee of the EULAR meeting, which took place in Berlin in 2012 and is in 2016 the elect Chair of the EULAR standing committee on investigative rheumatology. Professor Mariette is co-author of more than 430 publications referenced in PubMed with an H-index of 61.

  9. Del corpus theologicum de Xavier Zubiri a una pastoral de la Providencia en Latinoamérica

    Directory of Open Access Journals (Sweden)

    Adalberto Cardona Gómez

    2015-01-01

    Full Text Available A partir de los tres niveles de la experiencia de Dios en que, según Xavier Zubiri, se concretiza la Providencia divina: a experiencia universal de religación, propia de todo ser humano; b experiencia específicamente religiosa (gracia, en las que la iniciativa procede de Dios que se va revelando en el espacio y en el tiempo, a nivel individual, social e histórico; y c experiencia de la encarnación, constituida por la experiencia de la deiformidad, expresión esencial del cristianismo que se hace realidad en la persona de Cristo, en quien Dios asume forma humana y el hombre se deiformiza, este artículo se acerca a la Providencia por la vía de la encarnación, que le indica al hombre que la experiencia de Dios no lo aleja del mundo sino que lo obliga a él, constatación desde la que se propone para Latinoamérica una pastoral que integra responsablemente la idea de la Providencia de Dios.

  10. Dosimetry in occupational exposure workers of the medical institutes of the University San Francisco Xavier de Chuquisaca

    International Nuclear Information System (INIS)

    Zambrana Z, A. J.; Castro S, O.; Huanca S, E.; Torrez C, M.; Villca Q, I.

    2014-08-01

    In this work is made a retrospective analysis of the record, of the dosimetric control readings processed by the Dosimetry Laboratory of the Instituto Boliviano de Ciencia y Tecnologia Nuclear, as regulator entity at national level for Occupational Exposed Workers (OEWs) to ionizing radiations, of the Medical Institutes of the Universidad Mayor, Real y Pontificia de San Francisco Xavier de Chuquisaca, by a period of 10 and 15 years. The results showed that in the Nuclear Medicine Institute of Sucre, the Accumulated Occupational Exposure of a total of 393 readings of 15 OEWs was of 20.4 mSv, identifying as maximum value 10.2 mSv, in the official that develops the Radio-pharmacy activities (elution, fractionation, preparation and management). In the Instituto Nacional de Cancerologia Dr. Jose Cupertino Arteaga the dosimetric background registered an Accumulated Occupational Exposure of a total of 1319 readings of 50 OEWs of 309.69 mSv, with a maximum value of 62.30 mSv, corresponding to the worker of the technical area (maintenance, adjustment and calibration). Comparison that allows to infer that the difference is due mainly to the radio-active source type 99m Tc Vs 60 Co utilized in these health centers. (Author)

  11. Del corpus theologicum de Xavier Zubiri a una pastoral de la Providencia en Latinoamérica

    Directory of Open Access Journals (Sweden)

    Adalberto Cardona Gómez

    2015-07-01

    Full Text Available A partir de los tres niveles de la experiencia de Dios en que, según Xavier Zubiri, se concretiza la Providencia divina: a experiencia universal de religación, propia de todo ser humano; b experiencia específicamente religiosa (gracia, en las que la iniciativa procede de Dios que se va revelando en el espacio y en el tiempo, a nivel individual, social e histórico; y c experiencia de la encarnación, constituida por la experiencia de la deiformidad, expresión esencial del cristianismo que se hace realidad en la persona de Cristo, en quien Dios asume forma humana y el hombre se deiformiza, este artículo se acerca a la Providencia por la vía de la encarnación, que le indica al hombre que la experiencia de Dios no lo aleja del mundo sino que lo obliga a él, constatación desde la que se propone para Latinoamérica una pastoral que integra responsablemente la idea de la Providencia de Dios.

  12. Broadband Radiometric LED Measurements.

    Science.gov (United States)

    Eppeldauer, G P; Cooksey, C C; Yoon, H W; Hanssen, L M; Podobedov, V B; Vest, R E; Arp, U; Miller, C C

    2016-01-01

    At present, broadband radiometric measurements of LEDs with uniform and low-uncertainty results are not available. Currently, either complicated and expensive spectral radiometric measurements or broadband photometric LED measurements are used. The broadband photometric measurements are based on the CIE standardized V(λ) function, which cannot be used in the UV range and leads to large errors when blue or red LEDs are measured in its wings, where the realization is always poor. Reference irradiance meters with spectrally constant response and high-intensity LED irradiance sources were developed here to implement the previously suggested broadband radiometric LED measurement procedure [1, 2]. Using a detector with spectrally constant response, the broadband radiometric quantities of any LEDs or LED groups can be simply measured with low uncertainty without using any source standard. The spectral flatness of filtered-Si detectors and low-noise pyroelectric radiometers are compared. Examples are given for integrated irradiance measurement of UV and blue LED sources using the here introduced reference (standard) pyroelectric irradiance meters. For validation, the broadband measured integrated irradiance of several LED-365 sources were compared with the spectrally determined integrated irradiance derived from an FEL spectral irradiance lamp-standard. Integrated responsivity transfer from the reference irradiance meter to transfer standard and field UV irradiance meters is discussed.

  13. Dansk LED - Museumsbelysning

    DEFF Research Database (Denmark)

    Poulsen, Peter Behrensdorff; Dam-Hansen, Carsten; Thorseth, Anders

    Projektet har til formål at anvende dansk forskning inden for optik og lys til at realisere innovative energieffektive LED lyssystemer til museumsbranchen.......Projektet har til formål at anvende dansk forskning inden for optik og lys til at realisere innovative energieffektive LED lyssystemer til museumsbranchen....

  14. Integrating nurse-led Self-Management Support (SMS) in routine primary care: design of a hybrid effectiveness-implementation study among type 2 diabetes patients with problems of daily functioning and emotional distress: a study protocol.

    Science.gov (United States)

    van Dijk-de Vries, Anneke; van Bokhoven, Marloes A; Terluin, Berend; van der Weijden, Trudy; van Eijk, Jacques Th M

    2013-06-07

    Psychosocial problems are more prevalent among patients with chronic diseases than among the general population. They may lead to a downward spiral of poor adherence, deterioration of the condition and decline in daily functioning. In addition to medical management, systematic attention to emotional and role management tasks during routine chronic care seems mandatory. We intend to integrate an existing nurse-led minimal psychological intervention to support patients' self-management, which appeared to be effective and cost-effective, in routine care by primary care nurses, so we adjusted it to fit the host setting. The resulting Self-Management Support (SMS) programme involves early detection of patients with emotional distress and problems of daily functioning, as well as self-management support through problem solving and reattribution techniques. Strategies to embed SMS in daily practice include training and booster sessions for practice nurses as well as organisational and financial arrangements. This study aims to simultaneously evaluate the implementation process and effects of SMS in routine care, using a hybrid effectiveness-implementation design. Registration data, questionnaires and interviews will be used to explore the facilitators, barriers and costs regarding successful implementation of SMS. The effects of SMS will be evaluated in a pragmatic cluster-randomised controlled trial with a baseline measurement and follow-up measurements after 4 and 12 months. The population will consist of 46 practice nurses and their type 2 diabetes patients (N = 460; 10 per practice nurse). The practice nurses will be randomly assigned to the intervention or control group. Practice nurses of the intervention group will receive SMS training. Patients for the intervention and control groups will be recruited by a researcher-led self-administered screening procedure to decide which patients of those scheduled for routine consultation are likely to be detected by the

  15. Large area LED package

    Science.gov (United States)

    Goullon, L.; Jordan, R.; Braun, T.; Bauer, J.; Becker, F.; Hutter, M.; Schneider-Ramelow, M.; Lang, K.-D.

    2015-03-01

    Solid state lighting using LED-dies is a rapidly growing market. LED-dies with the needed increasing luminous flux per chip area produce a lot of heat. Therefore an appropriate thermal management is required for general lighting with LEDdies. One way to avoid overheating and shorter lifetime is the use of many small LED-dies on a large area heat sink (down to 70 μm edge length), so that heat can spread into a large area while at the same time light also appears on a larger area. The handling with such small LED-dies is very difficult because they are too small to be picked with common equipment. Therefore a new concept called collective transfer bonding using a temporary carrier chip was developed. A further benefit of this new technology is the high precision assembly as well as the plane parallel assembly of the LED-dies which is necessary for wire bonding. It has been shown that hundred functional LED-dies were transferred and soldered at the same time. After the assembly a cost effective established PCB-technology was applied to produce a large-area light source consisting of many small LED-dies and electrically connected on a PCB-substrate. The top contacts of the LED-dies were realized by laminating an adhesive copper sheet followed by LDI structuring as known from PCB-via-technology. This assembly can be completed by adding converting and light forming optical elements. In summary two technologies based on standard SMD and PCB technology have been developed for panel level LED packaging up to 610x 457 mm2 area size.

  16. LED roadway luminaires evaluation.

    Science.gov (United States)

    2012-02-01

    This research explores whether LED roadway luminaire technologies are a viable future solution to providing roadway lighting. Roadway lighting : enhances highway safety and traffic flow during limited lighting conditions. The purpose of this evaluati...

  17. Surface plasmon enhanced LED

    OpenAIRE

    Vučković, Jelena; Lončar, Marko; Painter, Oskar; Scherer, Axel

    2000-01-01

    Summary form only given. We designed and fabricated an LED based on a thin semiconductor membrane (λ/2) with silver mirrors. A large spontaneous emission enhancement and a high modulation speed are obtainable due to the strong localization of the electromagnetic field in the microcavity. The coupling to surface plasmon modes which are subsequently scattered out by means of a grating is used to improve the extraction efficiency of the LED. The bottom mirror is thick and unpatterned. The top mi...

  18. Light Emitting Diode (LED)

    Science.gov (United States)

    1997-01-01

    A special lighting technology was developed for space-based commercial plant growth research on NASA's Space Shuttle. Surgeons have used this technology to treat brain cancer on Earth, in two successful operations. The treatment technique called photodynamic therapy, requires the surgeon to use tiny pinhead-size Light Emitting Diodes (LEDs) (a source releasing long wavelengths of light) to activate light-sensitive, tumor-treating drugs. Laser light has been used for this type of surgery in the past, but the LED light illuminates through all nearby tissues, reaching parts of a tumor that shorter wavelengths of laser light carnot. The new probe is safer because the longer wavelengths of light are cooler than the shorter wavelengths of laser light, making the LED less likely to injure normal brain tissue near the tumor. It can also be used for hours at a time while still remaining cool to the touch. The LED probe consists of 144 tiny pinhead-size diodes, is 9-inches long, and about one-half-inch in diameter. The small balloon aids in even distribution of the light source. The LED light source is compact, about the size of a briefcase, and can be purchased for a fraction of the cost of a laser. The probe was developed for photodynamic cancer therapy by the Marshall Space Flight Center under a NASA Small Business Innovative Research program grant.

  19. Light Emitting Diodes (LEDs)

    Science.gov (United States)

    1997-01-01

    A special lighting technology was developed for space-based commercial plant growth research on NASA's Space Shuttle. Surgeons have used this technology to treat brain cancer on Earth, in two successful operations. The treatment technique, called Photodynamic Therapy, requires the surgeon to use tiny, pinhead-size Light Emitting Diodes (LEDs) (a source that releases long wavelengths of light ) to activate light-sensitive, tumor-treating drugs. 'A young woman operated on in May 1999 has fully recovered with no complications and no evidence of the tumor coming back,' said Dr. Harry Whelan, a pediatric neurologist at the Medical Hospital of Wisconsin in Milwaukee. Laser light has been used for this type of surgery in the past, but the LED light illuminates through all nearby tissues, reaching parts of a tumor that shorter wavelengths of laser light carnot. The new probe is safer because the longer wavelengths of light are cooler than the shorter wavelengths of laser light, making the LED less likely to injure normal brain tissue near the tumor. It can be used for hours at a time while still remaining cool to the touch. The LED light source is compact, about the size of a briefcase, and can be purchased for a fraction of the cost of a laser. The LEDs, developed and managed by NASA's Marshall Space Flight Center, have been used on seven Space Shuttle flights inside the Microgravity Astroculture Facility. This technology has also been successfully used to further commercial research in crop growth.

  20. Led-sukellusvalaisin

    OpenAIRE

    Saarelainen, Mikko

    2012-01-01

    Opinnäytetyön aiheena on LED ja sen käyttö sukellusvalaisimissa. Työn tarkoitus oli tutkia miten LED toimii ja miten se soveltuu käytettäväksi sukellusvalaisimessa, sekä syventää omaa tietoutta valosta, mitä se on ja miten sitä mitataan. Työssä käydään läpi LEDin ominaisuuksia ja miten se eroaa muista sukellusvalaisimissa käytetyistä lampuista. Työ on toteutettu tutustumalla LEDiin ja valoon käyttämällä erilaisia lähteitä ja päivittämällä nykyinen sukellusvalaisimeni LED-sukellusvalaisime...

  1. [LED lights in dermatology].

    Science.gov (United States)

    Noé, C; Pelletier-Aouizerate, M; Cartier, H

    2017-04-01

    The use in dermatology of light-emitting diodes (LEDs) continues to be surrounded by controversy. This is due mainly to poor knowledge of the physicochemical phases of a wide range of devices that are difficult to compare to one another, and also to divergences between irrefutable published evidence either at the level of in vitro studies or at the cellular level, and discordant clinical results in a variety of different indications: rejuvenation, acne, wound healing, leg ulcers, and cutaneous inflammatory or autoimmune processes. Therapeutic LEDs can emit wavelengths ranging from the ultraviolet, through visible light, to the near infrared (247-1300 nm), but only certain bands have so far demonstrated any real value. We feel certain that if this article remains factual, then readers will have a different, or at least more nuanced, opinion concerning the use of such LED devices in dermatology. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  2. Automotive LED lamp lighted appearance

    Science.gov (United States)

    Conn, Lawrence G.; Bennett, Larry R.

    2001-05-01

    The automotive optical engineer has an entirely new set of rules to follow for a 'smooth lighted appearance' with the introduction of LEDs into the automotive signal lighting market. To move away from the 'polka-dot' appearance long associated with the usage of LEDs as the light source for automotive lighting, and give the consumer a smooth lighted appearance to his lamp, there are several optical parameters that must be observed. The number and type of LEDs used, the size of the optical elements used, the spacing of the optical elements, plus many other factors all play a critical role and must be considered in the solution to the 'smooth lighted appearance' in an automotive signal lamp. The 'smooth lighted appearance' in an automotive signal lamp has long been a difficult problem to which there is more than one solution. The most visually pleasing and effective solution is not always the most easily obtainable solution since photometry requirements and smooth lighted appearance can be diametric goals. Subsequently the most cost effective and the easily 'doable' solution may not give the ultimate in aesthetically pleasing results for the consumer. Therefore, it is the purpose and intent of this paper to outline the parameters that need to be considered to obtain a 'smooth lighted appearance' for an automotive signal lamp, and to clarify the methods and 'tools' that are required to meet this goal.

  3. Thermal management for LED applications

    CERN Document Server

    Poppe, András

    2014-01-01

    Thermal Management for LED Applications provides state-of-the-art information on recent developments in thermal management as it relates to LEDs and LED-based systems and their applications. Coverage begins with an overview of the basics of thermal management including thermal design for LEDs, thermal characterization and testing of LEDs, and issues related to failure mechanisms and reliability and performance in harsh environments. Advances and recent developments in thermal management round out the book with discussions on advances in TIMs (thermal interface materials) for LED applications, advances in forced convection cooling of LEDs, and advances in heat sinks for LED assemblies. This book also: Presents a comprehensive overview of the basics of thermal management as it relates to LEDs and LED-based systems Discusses both design and thermal management considerations when manufacturing LEDs and LED-based systems Covers reliability and performance of LEDs in harsh environments Has a hands-on applications a...

  4. Deslumbramiento en dispositivos led

    OpenAIRE

    Ixtaina, Rubén Pablo; Presso, Matías; Ferreyra, Joaquín

    2012-01-01

    En el presente trabajo se presenta un estudio realizado en el LAL a dispositivos para señalización (semáforos, balizas, barrales lumínicos) con tecnología led. Las mediciones tradicionales de intensidad luminosa se complementaron con el análisis de la luminancia de los dispositivos, evaluada para diversas aperturas angula-res. Los resultados obtenidos marcan un notorio incre-mento en las luminancias puntuales, para valores de emisión globales comparables a los obtenidos en dispo-sitivos conve...

  5. Harmonics Monitoring Survey on LED Lamps

    Directory of Open Access Journals (Sweden)

    Abdelrahman Ahmed Akila

    2017-03-01

    Full Text Available Light Emitting Diode (LED lamps are being increasingly used in many applications. These LED lamps operate using a driver, which is a switching device. Hence, LED lamps will be a source of harmonics in the power system. These harmonics if not well treated, may cause severe performance and operational problems. In this paper, harmonics (amplitude and phase angles generated by both LED lamps and conventional fluorescent lamps will be studied practically. Then they will be analyzed and evaluated. Compared to each other harmonics generated by both LED and conventional florescent lamps, self mitigation may occur based on the phase angle of these harmonics. All data will be measured using power analyzer and will be done on a sample of actual lamps.

  6. Padre Vieira: sonhos proféticos, profecias oníricas. O tempo do Quinto Império nos sermões de Xavier Dormindo.

    OpenAIRE

    Luis Filipe Silverio Lima

    2000-01-01

    O objetivo desta pesquisa é investigar os sonhos proféticos dentro dos sermões de Xavier Dormindo do jesuíta português Antonio Vieira (1608-1697), observando a questão do tempo. Além de questões pouco abordadas nos estudos vieirenses, os sonhos, a profecia e o tempo se configuram como elementos para uma compreensão do V Império, matéria à qual Vieira se dedicou durante grande parte de sua vida e possível chave para a confecção de uma "Teoria Geral do Pe. Vieira" . A leitura desses sermões ...

  7. Resultados Preliminares (ta Ventilação de Alta Frequência na Unidade de Neonatologia do Hospital São Francisco Xavier

    OpenAIRE

    P., Lóio; M. A., Bispo; J. M., Palminha

    2014-01-01

    No Hospital São Francisco Xavier foram ventilados durante o ano de 1996 (Janeiro 1996 a Dezembro 1996), sob o protocolo de ventilação de alta frequência (VAF) 17 recém-nascidos que cumpriram os critérios pré-estabelecidos para admissão no estudo.Estes critérios foram os seguintes: 1) critérios de idade ou peso: recém-nascidos com menos de 1500 gramas ou 31 semanas de idade gestacional com necessidade de ventilação mecânica exigindo Fi02 de 30% e frequência respiratória do ventilador maior que...

  8. Conférence | À quelle distance sommes-nous des Lumières ? | Etienne Klein et François-Xavier Verger | 4 mars

    CERN Document Server

    2015-01-01

    À quelle distance sommes-nous des Lumières ?, par Etienne Klein et François-Xavier Verger.   Mercredi 4 mars 2015 à 20h30 Globe de la science et de l'innovation Route de Meyrin, 1211 Genève Soirée en français Etienne Klein : L'esprit des Lumières promeut l’autonomie de l’entendement et la primauté de l’esprit scientifique. Il pose également la finalité humaine de nos actes – on ne vise pas Dieu, mais les hommes –, et l’universalité, notamment celle des droits de l’homme. Nous nous considérons volontiers comme les héritiers des Lumières. Mais à quelle distance sommes-nous réellement de leur esprit ? Etienne Klein est physicien, directeur de recherches au CEA et docteur en philosophie des sciences. Il est professeur &a...

  9. En el Bicentenario: consideraciones en torno al paradigma de François-Xavier Guerra sobre las “revoluciones hispánicas”

    Directory of Open Access Journals (Sweden)

    Medófilo Medina Pineda

    2010-01-01

    Full Text Available El autor ofrece una aproximación de conjunto sobre el paradigma interpretativo las revoluciones hispánicas, construido por el profesor francés François-Xavier Guerra sobre la crisis de la monarquía española a comienzos del siglo XIX y las “independencias” hispanoamericanas. La visión de Guerra se aborda, por un lado, en relación con las investigaciones que desde la perspectiva del concepto de las “revoluciones atlánticas” se adelantaron desde finales del decenio de 1940 en Francia y los Estados Unidos, y por el otro, con la obra y acción política del historiador François Furet sobre la Revolución Francesa. El sentido crítico de estas “consideraciones” se origina no tanto en las características de un ensayo historiográfico sino en las necesidades de atender demandas de interpretación sobre la Independencia hispanoamericana.

  10. LED driver for stroboscopic interferometry

    Science.gov (United States)

    Paulin, T.; Heikkinen, V.; Kassamakov, I.; Hæggström, E.

    2012-04-01

    Three different types of white light emitting diodes (LEDs) and three types of single color LEDs were tested as light sources for stroboscopic scanning white light interferometry (SSWLI) for dynamic (MEMS) characterization. Short, intense, light pulses and low duty cycle (DC-10 MHz), and can drive single LEDs at 5A peak current (0.7% duty cycle at 1 MHz). The shortest measured electrical pulses were 6.2 +/- 0.1 ns FDHM. The minimum measured Full Duration at Half Maximum (FDHM) of the optical pulse was 8.4 +/- 0.1 ns using nonphosphor white LED and 32.1 +/- 0.1 ns using white phosphor-converted LED (0.7 % duty cycle at 1 MHz in both cases). The minimum optical pulse FDHM for a single color blue/green LED was 6.4 +/- 0.1 ns. The maximum intensity of these pulses was 630 +/- 40 μW and 540 +/- 30 μW, respectively. All types of white LEDs could be used for stroboscopic SWLI measurements at frequencies up to 2 MHz. For higher frequencies, non-phosphor white LEDs must be used together with a cyan LED to avoid ringing in the SWLI interferogram.

  11. Nobel Prize for blue LEDs

    International Nuclear Information System (INIS)

    Kraftmakher, Yaakov

    2015-01-01

    A brief review of lighting technologies is presented. Unavoidable restrictions for incandescent light bulbs caused by the Planck distribution and properties of the human eye are illustrated. The efficiency and luminous efficacy of thermal radiation are calculated for various temperatures; the results clearly show the limitations for thermal radiators. The only way to overcome these limitations is using non-thermal radiators, such as fluorescent lamps and light-emitting diodes (LEDs). Unique advantages of LEDs undoubtedly made a revolution in this field. A crucial element of this progress is the blue LEDs (Nobel Prize 2014). Some experiments with a blue and a green LED are described: (i) the luminescence triggered in a green-yellow phosphor inside a white LED by the blue LED; (ii) radiant spectra and ‘efficiency droop’ in the LEDs; (iii) modulation of the blue LED up to 4 MHz; and (iv) the h/e ratio from the turn-on voltage of the green LED. The experiments are suitable for undergraduate laboratories and usable as classroom demonstrations. (paper)

  12. Nobel Prize for blue LEDs

    Science.gov (United States)

    Kraftmakher, Yaakov

    2015-05-01

    A brief review of lighting technologies is presented. Unavoidable restrictions for incandescent light bulbs caused by the Planck distribution and properties of the human eye are illustrated. The efficiency and luminous efficacy of thermal radiation are calculated for various temperatures; the results clearly show the limitations for thermal radiators. The only way to overcome these limitations is using non-thermal radiators, such as fluorescent lamps and light-emitting diodes (LEDs). Unique advantages of LEDs undoubtedly made a revolution in this field. A crucial element of this progress is the blue LEDs (Nobel Prize 2014). Some experiments with a blue and a green LED are described: (i) the luminescence triggered in a green-yellow phosphor inside a white LED by the blue LED; (ii) radiant spectra and ‘efficiency droop’ in the LEDs; (iii) modulation of the blue LED up to 4 MHz; and (iv) the h/e ratio from the turn-on voltage of the green LED. The experiments are suitable for undergraduate laboratories and usable as classroom demonstrations.

  13. New dental applications with LEDs

    DEFF Research Database (Denmark)

    Argyraki, A.; Ou, Yiyu; Petersen, Paul Michael

    Visible and ultraviolet LEDs will in the future give rise to new dental applications. Fluorescence imaging, photodynamic therapy and photoactivated disinfection are important future candidates for diagnostics and treatment in dentistry.......Visible and ultraviolet LEDs will in the future give rise to new dental applications. Fluorescence imaging, photodynamic therapy and photoactivated disinfection are important future candidates for diagnostics and treatment in dentistry....

  14. Silicone materials for LED packaging

    Science.gov (United States)

    Bahadur, Maneesh; Norris, Ann W.; Zarisfi, Afrooz; Alger, James S.; Windiate, Christopher C.

    2006-08-01

    Silicone based materials have attracted considerable attention from light emitting diode (LED) manufacturers for use as encapsulants and lenses for many high brightness LED (HB LED) devices. Currently silicones function in two key roles in HB LED devices, (1) as protective lenses and (2) stress relieving encapsulants for wire bond protection. The key attributes of silicones that make them attractive as light path materials for high brightness HB LEDs include their high transparency in the UV-visible region, controlled refractive index (RI), stable thermo-mechanical properties, and tuneable modulus from soft gels to hard resins. This paper will describe recent developments in moldable silicone hard resin materials. Progress on cavity moldable and liquid injection moldable (LIM) silicone compositions for discreet components is described. Also, an example of liquid injection overmolding is presented.

  15. Energy efficient LED layout optimization for near-uniform illumination

    Science.gov (United States)

    Ali, Ramy E.; Elgala, Hany

    2016-09-01

    In this paper, we consider the problem of designing energy efficient light emitting diodes (LEDs) layout while satisfying the illumination constraints. Towards this objective, we present a simple approach to the illumination design problem based on the concept of the virtual LED. We formulate a constrained optimization problem for minimizing the power consumption while maintaining a near-uniform illumination throughout the room. By solving the resulting constrained linear program, we obtain the number of required LEDs and the optimal output luminous intensities that achieve the desired illumination constraints.

  16. Practical lighting design with LEDs

    CERN Document Server

    Lenk, Ron

    2016-01-01

    The second edition of Practical Lighting Design with LEDs has been revised and updated to provide the most current information for developing light-emitting diodes products. The authors, noted authorities in the field, offer a review of the most relevant topics including optical performance, materials, thermal design, and modeling and measurement. Comprehensive in scope, the text covers all the information needed to design LEDs into end products.

  17. A intelecção da realidade deus enquanto fundamento da existência humana na metafísica de Xavier Zubiri

    Directory of Open Access Journals (Sweden)

    Alan Leal de Mattos

    2016-12-01

    Full Text Available O presente artigo pretende oferecer uma contribuição para a reflexão filosófica acerca de Deus abordando a perspectiva metafísica de Xavier Zubiri. Seu principal intento ao tratar de Deus enquanto problema teologal é o de abrir uma possibilidade de reflexão existencial, ou seja, a partir do homem que não está fechado numa facticidade, mas que esteja aberto para o transcendental. Dando breves acenos sobre os temas da realidade e da inteligência, buscou-se, por meio de uma metodologia de análise bibliográfica, dar uma base mínima do pensamento zubiriano. A partir dessas bases o problema teologal, no qual coincidem o problema do homem e de Deus, se torna uma investigação acerca da própria existência humana enquanto atualização a partir da realidade-fundamento, a partir de Deus. Sendo Deus uma transcêndencia “nas” coisas e no homem enquanto presença alterificante que possibilita ao homem se dirigir a um “Tu” para, numa experiência de liberdade, realizar seu “Eu pessoal” a partir desse fundamento, o pensamento de Zubiri abre uma reflexão para o homem que o convoca para a tarefa de fazer seu Eu fundantemente, isto é, enquanto “modo finito de ser Deus”, a partir daquele que se encontra no de profundis da existência humana, mas que eleva tudo ao in excelsis da vida em plenitude.

  18. Development of thermal LED Model | Kapitonov | Journal of ...

    African Journals Online (AJOL)

    One of the main tasks of modern lighting technology is to increase the reliability of LED technology. In order to solve this problem, it is necessary to ensure an effective cooling of LEDs, since the values of their parameters depend substantially on the temperature of a crystal. This dependence makes a significant effect on the ...

  19. Semiconductor lasers and herterojunction leds

    CERN Document Server

    Kressel, Henry

    2012-01-01

    Semiconductor Lasers and Heterojunction LEDs presents an introduction to the subject of semiconductor lasers and heterojunction LEDs. The book reviews relevant basic solid-state and electromagnetic principles; the relevant concepts in solid state physics; and the p-n junctions and heterojunctions. The text also describes stimulated emission and gain; the relevant concepts in electromagnetic field theory; and the modes in laser structures. The relation between electrical and optical properties of laser diodes; epitaxial technology; binary III-V compounds; and diode fabrication are also consider

  20. Extracting light out of LEDs

    Science.gov (United States)

    Muschaweck, Julius; Wiesmann, Christopher

    2013-08-01

    `External quantum efficiency', that is, the number of photons generated per electron passing through the p-n junction of an LED is probably the most important number to quantify the performance of an LED chip. Although advances in epitaxy have increased the fraction of radiative recombination to extremely high values, the extraction of the precious photons that are trapped in a high refractive index crystal is still tricky. In this brief tutorial, we look at the physics of light extraction both from a geometrical optics/thermodynamic and a wave optics point of view, discussing both random and deterministic surface structures.

  1. White LED motorcycle headlamp design

    Science.gov (United States)

    Sun, Wen-Shing

    2015-09-01

    The motorcycle headlamp is composed of a white LED module, an elliptical reflector, a parabolic reflector and a toric lens. We use non-sequential ray to improve the optical efficiency of the compound reflectors. Using the toric lens can meet ECE_113 regulation and obtain a good uniformity.

  2. UV-LED photopolymerised monoliths

    Czech Academy of Sciences Publication Activity Database

    Abele, S.; Nie, F.; Foret, František; Paull, B.; Macka, M.

    2008-01-01

    Roč. 133, č. 7 (2008), s. 864-866 ISSN 0003-2654 R&D Projects: GA AV ČR KAN400310651 Institutional research plan: CEZ:AV0Z40310501 Keywords : photopolymerisation * UV-LED * polymethacrylate monolith Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.761, year: 2008

  3. Architecture-Led Safety Process

    Science.gov (United States)

    2016-12-01

    Contents Acknowledgments iv Abstract v 1 Introduction 1 2 Architecture -Led Processes and ALSA 2 3 ALSA Practices 5 3.1 Example System 8 4 Identify... Architecture Models 13 5 Identify Operational Hazards and Hazard Contributors 15 5.1 System Partitioning 15 5.2 Operational Context as a Control

  4. LED lamp power management system and method

    Science.gov (United States)

    Gaines, James; Clauberg, Bernd; Van Erp, Josephus A. M.

    2013-03-19

    An LED lamp power management system and method including an LED lamp having an LED controller 58; a plurality of LED channels 60 operably connected to the LED controller 58, each of the plurality of LED channels 60 having a channel switch 62 in series with at least one shunted LED circuit 83, the shunted LED circuit 83 having a shunt switch 68 in parallel with an LED source 80. The LED controller 58 reduces power loss in one of the channel switch 62 and the shunt switch 68 when LED lamp electronics power loss (P.sub.loss) exceeds an LED lamp electronics power loss limit (P.sub.lim); and each of the channel switches 62 receives a channel switch control signal 63 from the LED controller 58 and each of the shunt switches 68 receives a shunt switch control signal 69 from the LED controller 58.

  5. LED lamp color control system and method

    Science.gov (United States)

    Gaines, James; Clauberg, Bernd; Van Erp, Josephus A.M.

    2013-02-05

    An LED lamp color control system and method including an LED lamp having an LED controller 58; and a plurality of LED channels 60 operably connected to the LED controller 58, each of the plurality of LED channels 60 having a channel switch 62 in series with at least one shunted LED circuit 83, the shunted LED circuit 83 having a shunt switch 68 in parallel with an LED source 80. The LED controller 58 determines whether the LED source 80 is in a feedback controllable range, stores measured optical flux for the LED source 80 when the LED source 80 is in the feedback controllable range, and bypasses storing the measured optical flux when the LED source 80 is not in the feedback controllable range.

  6. Celebrity-led development organisations

    DEFF Research Database (Denmark)

    Budabin, Alexandra Cosima; Rasmussen, Louise Mubanda; Richey, Lisa Ann

    2017-01-01

    The past decade has seen a frontier open up in international development engagement with the entrance of new actors such as celebrity-led organisations. We explore how such organisations earn legitimacy with a focus on Madonna’s Raising Malawi and Ben Affleck’s Eastern Congo Initiative. The study...... draws from organisational materials, interviews, mainstream news coverage, and the texts of the celebrities themselves to investigate the construction of authenticity, credibility, and accountability. We find these organisations earn legitimacy and flourish rapidly amid supportive elite networks...... for funding, endorsements, and expertise. We argue that the ways in which celebrity-led organisations establish themselves as legitimate development actors illustrate broader dynamics of the machinery of development....

  7. Luminescent ceramics for LED conversion

    Science.gov (United States)

    Raukas, M.; Wei, G.; Bergenek, K.; Kelso, J.; Zink, N.; Zheng, Y.; Hannah, M.; Stough, M.; Wirth, R.; Linkov, A.; Jermann, F.; Eisert, D.

    2011-03-01

    Many LED-based applications would benefit from more efficient and/or high lumen output devices that enable usage in both white and single color illumination schemes. In the present article we briefly review the materials research history leading to optical ceramic converters and discuss their typical characteristics. Recently demonstrated high performance values in terms of efficacy and external quantum efficiency in orange (amber) spectral region are described.

  8. Are nurse-led chemotherapy clinics really nurse-led? An ethnographic study.

    Science.gov (United States)

    Farrell, Carole; Walshe, Catherine; Molassiotis, Alex

    2017-04-01

    The number of patients requiring ambulatory chemotherapy is increasing year on year, creating problems with capacity in outpatient clinics and chemotherapy units. Although nurse-led chemotherapy clinics have been set up to address this, there is a lack of evaluation of their effectiveness. Despite a rapid expansion in the development of nursing roles and responsibilities in oncology, there is little understanding of the operational aspects of nurses' roles in nurse-led clinics. To explore nurses' roles within nurse-led chemotherapy clinics. A focused ethnographic study of nurses' roles in nurse-led chemotherapy clinics, including semi-structured interviews with nurses. Four chemotherapy units/cancer centres in the UK PARTICIPANTS: Purposive sampling was used to select four cancer centres/units in different geographical areas within the UK operating nurse-led chemotherapy clinics. Participants were 13 nurses working within nurse-led chemotherapy clinics at the chosen locations. Non-participant observation of nurse-led chemotherapy clinics, semi-structured interviews with nurse participants, review of clinic protocols and associated documentation. 61 nurse-patient consultations were observed with 13 nurses; of these 13, interviews were conducted with 11 nurses. Despite similarities in clinical skills training and prescribing, there were great disparities between clinics run by chemotherapy nurses and those run by advanced nurse practitioners. This included the number of patients seen within each clinic, operational aspects, nurses' autonomy, scope of practice and clinical decision-making abilities. The differences highlighted four different levels of nurse-led chemotherapy clinics, based on nurses' autonomy and scope of clinical practice. However, this was heavily influenced by medical consultants. Several nurses perceived they were undertaking holistic assessments, however they were using medical models/consultation styles, indicating medicalization of nurses' roles

  9. El proceso de revisión a la traducción de Francisco Xavier Balmis del Tratado histórico y práctico de la vacuna, de Moreau de la Sarthe The revision process of Francisco Xavier Balmis' translation of Moreau de la Sarthe's Historical and Practical Treatise on Vaccines

    Directory of Open Access Journals (Sweden)

    José Tuells

    2012-08-01

    Full Text Available El Tratado histórico y práctico de la vacuna de Moreau de la Sarthe, traducido por Francisco Xavier de Balmis y publicado en 1803, fue uno de los protagonistas de la Real Expedición Filantrópica de la Vacuna, convirtiéndose en el primer Manual de Vacunaciones oficial reconocido así por un gobierno. En 1801, Balmis decide traducirlo, y se suma a la primera hornada de difusores del método de Edward Jenner en España. Analizamos el procedimiento a que fue sometido desde su envío para revisión hasta su edición final, en el que transcurren 16 meses. Tras una remisión incompleta, el revisor señala a Balmis errores en el estilo, en la propia traducción y omisiones a pasajes de la obra original. La decisión final tras las correcciones fue de aceptación, aunque no obtuvo la autorización deseada por Balmis para incluir una dedicatoria a la Reina, hecho que incrementaría su impacto, justificado en la consideración de que no era una obra singular en su género o de un mérito sobresaliente. Finalmente, Balmis lo dedica a las madres de familia. Con una tirada inicial de 500 ejemplares y una inmediata posterior de 2000, tuvo una amplia difusión en la América latina. El estudio destaca la influencia de los evaluadores en la calidad de la producción científica.Moreau de la Sarthe's Traité historique et pratique de la vaccine, translated by Francisco Xavier de Balmis and published in 1803, was one of the protagonists of the Royal Philanthropic Expedition of the Vaccine, and became the first official vaccination manual recognized by a government. Balmis decided to translate Moreau's work in 1801, joining the first generation of disseminators of Edward Jenner's method in Spain. The translation process from return for review to final publication 16 months later is analyzed in this article. After Balmis submitted the still-incomplete work, the reviewer pointed out errors in style and in the translation itself, and omissions of passages from

  10. LEDs Illuminate Bulbs for Better Sleep, Wake Cycles

    Science.gov (United States)

    2015-01-01

    Life on the International Space Station (ISS) wreaks havoc on an astronaut’s biological rhythms, and one way NASA mitigates the problem is through the use of LED lighting to alternately stimulate energy and focus and induce relaxation. Satellite Beach, Florida-based Lighting Science partnered with Kennedy Space Center to commercialize an LED system designed for the ISS, resulting in its DefinityDigital product line of light bulbs now used in numerous homes, hotel chains, and resorts.

  11. Practical lighting design with LEDs

    CERN Document Server

    Lenk, Ron

    2011-01-01

    "This book covers all of the information needed to design LEDs into end-products. It is a practical guide, primarily explaning how things are done by practicing engineers. Equations are used only for practical calculations, and are kept to the level of high-school algebra. There are numerous drawings and schematics showing how things such as measurements are actually made, and showing curcuits that actually work. There are practical notes and examples embedded in the text that give pointers and how-to guides on many of the book's topics. After reading each chapter of the book, readers will have the knowledge to implement practical designs. This book will be kept as a reference tool for years to come"--

  12. Xavier Poux (coord., 2006, Agriculture, environnement et territoires. Quatre scénarios à l’horizon 2025, Paris, La documentation Française, 222 p.

    Directory of Open Access Journals (Sweden)

    Florence Cantrelle

    2008-10-01

    Full Text Available Comment les relations agriculture/environnement vont-elles évoluer à l’avenir ? L’ouvrage coordonné par Xavier POUX, rend compte du travail mené par le Groupe de la Bussière, composé d’acteurs de terrain, de scientifiques de diverses disciplines et de membres des différents ministères mandataires. L’exercice, à l’initiative du Ministère de l’Agriculture, de l’Alimentation, de la Pêche et des Affaires rurales, du Ministère de l’Environnement et du Développement Durable (MEDD et du Centre Nati...

  13. Multigrid solvers and multigrid preconditioners for the solution of variational data assimilation problems

    Science.gov (United States)

    Debreu, Laurent; Neveu, Emilie; Simon, Ehouarn; Le Dimet, Francois Xavier; Vidard, Arthur

    2014-05-01

    In order to lower the computational cost of the variational data assimilation process, we investigate the use of multigrid methods to solve the associated optimal control system. On a linear advection equation, we study the impact of the regularization term on the optimal control and the impact of discretization errors on the efficiency of the coarse grid correction step. We show that even if the optimal control problem leads to the solution of an elliptic system, numerical errors introduced by the discretization can alter the success of the multigrid methods. The view of the multigrid iteration as a preconditioner for a Krylov optimization method leads to a more robust algorithm. A scale dependent weighting of the multigrid preconditioner and the usual background error covariance matrix based preconditioner is proposed and brings significant improvements. [1] Laurent Debreu, Emilie Neveu, Ehouarn Simon, François-Xavier Le Dimet and Arthur Vidard, 2014: Multigrid solvers and multigrid preconditioners for the solution of variational data assimilation problems, submitted to QJRMS, http://hal.inria.fr/hal-00874643 [2] Emilie Neveu, Laurent Debreu and François-Xavier Le Dimet, 2011: Multigrid methods and data assimilation - Convergence study and first experiments on non-linear equations, ARIMA, 14, 63-80, http://intranet.inria.fr/international/arima/014/014005.html

  14. LEDs light up the world

    Energy Technology Data Exchange (ETDEWEB)

    Mather, N.

    2004-06-30

    A lighting system using light-emitting diodes, and privately financed by a Canadian engineering professor at the University of Calgary, has been set up in a village in Nepal in 2000. Since then, through the efforts of the 'Light Up The World' Foundation, established by Dr. Irvine-Halliday, projects have lit up thousands of homes in the Philippines, India, Afghanistan, the Galapagos Islands, Mexico, Sri Lanka, and Angola. Although the goal of the project is primarily to provide lighting for reading and writing for school-children, the project has been the source of many other advantages; creation of enterprise, increased employment, enhanced income, gender equality, and improvements in health and safety among them. Since LED lamps in most cases replace kerosene lamps, the system also has significant environmental benefits. The system as originally envisioned creates electricity by pedal-powered generator, or by solar panels connected to a battery, depending on what is available at each home. Each home is connected to the power supply and supplied with low-energy diode lamps. The lights are extremely efficient and many homes can be equipped with them using less energy than it takes to power a single 100-watt light bulb. 5 photos.

  15. Dome diagnostics system of optical parameters and characteristics of LEDs

    Science.gov (United States)

    Peretyagin, Vladimir S.; Pavlenko, Nikita A.

    2017-09-01

    Scientific and technological progress of recent years in the production of the light emitting diodes (LEDs) has led to the expansion of areas of their application from the simplest systems to high precision lighting devices used in various fields of human activity. However, development and production (especially mass production) of LED lighting devices are impossible without a thorough analysis of its parameters and characteristics. There are many ways and devices for analysis the spatial, energy and colorimetric parameters of LEDs. The most methods are intended for definition only one parameter (for example, luminous flux) or one characteristic (for example, the angular distribution of energy or the spectral characteristics). Besides, devices used these methods are intended for measuring parameters in only one point or plane. This problem can be solved by using a dome diagnostics system of optical parameters and characteristics of LEDs, developed by specialists of the department OEDS chair of ITMO University in Russia. The paper presents the theoretical aspects of the analysis of LED's spatial (angular), energy and color parameters by using mentioned of diagnostics system. The article also presents the results of spatial), energy and color parameters measurements of some LEDs brands.

  16. Novel clinical learning from a student-led clinic.

    Science.gov (United States)

    Bostick, Geoff; Hall, Mark; Miciak, Maxi

    2014-12-01

    Student-led clinics have the potential to meet community rehabilitation needs and provide valuable clinical placement experiences. Student-led clinical learning may offer pedagogical advantages similar to problem-based learning; however, this line of research is new and little is known about student-led clinical learning. The purpose of this study was to describe the novel learning experiences of a clinical placement in a student-led clinic from student perspectives. We conducted a descriptive qualitative focus group study with six participants. The focus group began with an open-ended question: 'What does the student-led clinic mean to you as a learner?' This was followed by a discussion of three topics: (1) the student-led clinic is learner focused; (2) faculty involvement in supervision; and (3) learning in a shared space with other students. A content analysis was used to analyse the data, and a summary of the researcher's interpretations was sent to study participants for further comments. There were two major themes that represented experiences within the student-led clinic. 'Increased responsibility' was viewed as a novel experience, and as reducing the perceived gap between the classroom and the 'real world'. As clinical instructors do not carry their own caseload, the second theme pertained to 'Safety-in-learning'. Although this theme was not viewed as novel, it was perceived to be important in enabling autonomy. Increased responsibility' was viewed and as reducing the perceived gap between the classroom and the 'real world Student-led clinics have clear community benefits by mitigating service gaps while providing experiential learning opportunities. These learning opportunities are perceived to be novel, and may resemble advantages observed in the classroom with problem-based learning. © 2014 John Wiley & Sons Ltd.

  17. Fokusgruppeinterview som led i en evalueringsproces

    DEFF Research Database (Denmark)

    Andersen-Mølgaard, Hanna; Harrit, Ole

    2006-01-01

    Teoretiske begrundelser og perspektiver, responsiv-konstruktivistisk evaluering, fokusgruppeinterview som led i BIKVAmodellen, eksempler, vurdering og perspektivering......Teoretiske begrundelser og perspektiver, responsiv-konstruktivistisk evaluering, fokusgruppeinterview som led i BIKVAmodellen, eksempler, vurdering og perspektivering...

  18. Evaluation of LED vehicular and pedestrian modules.

    Science.gov (United States)

    2009-04-01

    This study was conducted to verify the compliance of vehicular and pedestrian LED traffic signal modules with the Institute : of Transportation Engineers specifications; and to assess drivers preferences of the LED modules. Four vehicular modules ...

  19. Goniometric characterization of LED based greenhouse lighting

    DEFF Research Database (Denmark)

    Thorseth, Anders; Lindén, Johannes; Corell, Dennis Dan

    2015-01-01

    This paper describes a demonstration of goniospectroradiometry for characterizations of new light emitting diode (LED) based luminaries for enhanced photosynthesis in greenhouses. It highlights the differences between measurement of the traditional high pressure sodium (HPS) luminaries and the LED...

  20. Goniometric characterization of LED based greenhouse lighting

    DEFF Research Database (Denmark)

    Thorseth, Anders; Lindén, Johannes; Corell, Dennis Dan

    2015-01-01

    This paper describes a demonstration of goniospectroradiometry for characterizations of new light emitting diode (LED) based luminaries for enhanced photosynthesis in greenhouses. It highlights the differences between measurement of the traditional high pressure sodium (HPS) luminaries and the LED...... based luminaries. The LED based luminaries are compared to traditional HPS luminaries; in terms of energy efficiency with regard to the photosynthetic photon flux, and the LED luminaries were found to be more effective than the HPS luminaries...

  1. LED belichting tijdens het voortrekken van lelie

    NARCIS (Netherlands)

    Kok, B.J.; Wildschut, J.

    2010-01-01

    De laatste jaren staat het gebruik van LED-lampen in de tuinbouw in de belangstelling. Uit vele onderzoeken is al gebleken dat LED-lampen op dit moment nog geen alternatief zijn voor de SON-T lampen. Het grote voordeel van LED-lampen is dat ze monochromatisch licht van alle mogelijke golflengtes

  2. ‘No Blue’ White LED

    DEFF Research Database (Denmark)

    Ou, Haiyan; Corell, Dennis Dan; Dam-Hansen, Carsten

    2010-01-01

    This paper explored the feasibility of making a white LED light source by color mixing method without using the blue color. This ‘no blue’ white LED has potential applications in photolithography room illumination, medical treatment and biophotonics research. A no-blue LED was designed, and the p...

  3. Plant growth with Led lighting systems

    International Nuclear Information System (INIS)

    Campiotti, C.A.; Bernardini, A.; Di Carlo, F.; Scoccianti, M.; Alonzo, G.; Carlino, M.; Dondi, F.; Bibbiani, C.

    2009-01-01

    Leds lighting is highly relevant for the horticultural industry. Compared to other light sources used for plant production, leds have several properties which are potentially useful in relation to horticulture. However, although LEDs technology has raised strong interest in research for extraterrestrial agriculture, current LEDs panel costs are still too high for commercial adoption in greenhouse sector, and their electrical efficacies do not compete with those of high-pressure sodium lamps, but several manufactures are working to address these issues. When LEDs become practical, their ability to based light sources specifically suitable for photosynthesis and other horticulturally relevant plant properties (i.e. low radiated heat; lighting from within the canopy) will render the narrow band spectrum of LEDs of particular interest for providing light to greenhouse horticulture. A general description of LEDs application and their technical characteristics is briefly reported. [it

  4. Generation of solar spectrum by using LEDs

    Science.gov (United States)

    Lu, Pengzhi; Yang, Hua; Pei, Yanrong; Li, Jing; Xue, Bin; Wang, Junxi; Li, Jinmin

    2016-09-01

    Light emitting diode (LED) has been recognized as an applicable light source for indoor and outdoor lighting, city beautifying, landscape facilities, and municipal engineering etc. Conventional LED has superior characteristics such as long life time, low power consumption, high contrast, and wide viewing angle. Recently, LED with high color-rendering index and special spectral characteristics has received more and more attention. This paper is intended to report a solar spectrum simulated by multichip LED light source. The typical solar spectrum of 5500k released by CIE was simulated as a reference. Four types of LEDs with different spectral power distributions would be used in the LED light source, which included a 430nm LED, a 480nm LED, a 500nm LED and a white LED. In order to obtain better simulation results, the white LED was achieved by a 450nm LED chip with the mixture of phosphor. The phosphor combination was prepared by mixing green phosphor, yellow phosphor and red phosphor in a certain proportion. The multichip LED light source could provide a high fidelity spectral match with the typical solar spectrum of 5500k by adjusting injection current to each device. The luminous flux, CIE chromaticity coordinate x, y, CCT, and Ra were 104.7 lm, 0.3337, 0.3681, 5460K, and 88.6, respectively. Because of high color-rendering index and highly match to the solar spectrum, the multichip LED light source is a competitive candidate for applications where special spectral is required, such as colorimetric measurements, visual inspection, gemstone identification and agriculture.

  5. Testing Finance-Led, Export-Led and Import-Led Growth Hypotheses on Four Sub-Saharan African Economies

    OpenAIRE

    Evans, Olaniyi

    2013-01-01

    This study carries out an empirical examination of the finance-led, export-led and import-led growth hypothesis for four of the largest Sub-Saharan African economies namely South Africa, Nigeria, Ghana and Kenya. Within a multivariate Vector-Auto Regressive (VAR) framework, the concept of Granger causality is employed to determine the direction of causation between exports and output, duly taking into account the stationarity properties of the time series data. With further substantiation fro...

  6. Reported challenges in nurse-led randomised controlled trials

    DEFF Research Database (Denmark)

    Wang Vedelø, Tina; Lomborg, Kirsten

    2011-01-01

    , nursing research, nursing, research, challenges, barriers, nurse's role, nurse attitude, attitude of health personnel. Findings: The literature on reported challenges and barriers between 1999 and 2009 showed that the most often experienced problems were (i) sufficient patient recruitment, (ii...... between nurse researchers and clinicians, including education, training and support may increase the success rate and quality of nurse-led studies using the randomised controlled trial.......Aims: The purpose of this integrative literature review was to explore and discuss the methodological challenges nurse researchers report after conducting nurse-led randomised controlled trials in clinical hospital settings. Our research questions were (i) what are the most commonly experienced...

  7. LEDs for general and horticultural lighting

    OpenAIRE

    Girón González, Emilio

    2012-01-01

    The work begins with an introductory part about Light Emitting Diode (or LEDs) and how these devices work. This report also shows an overview of different artificial light sources such as incandescent lamps, fluorescents tube and high-intensity discharge (HID) lamps. The LED lighting is more energy-efficient than other artificial lighting, since they require less energy to operate. The following part of the work reports LEDs for General Lighting that describes some basic concepts such as spec...

  8. System Reliability for LED-Based Products

    Energy Technology Data Exchange (ETDEWEB)

    Davis, J Lynn; Mills, Karmann; Lamvik, Michael; Yaga, Robert; Shepherd, Sarah D; Bittle, James; Baldasaro, Nick; Solano, Eric; Bobashev, Georgiy; Johnson, Cortina; Evans, Amy

    2014-04-07

    Results from accelerated life tests (ALT) on mass-produced commercially available 6” downlights are reported along with results from commercial LEDs. The luminaires capture many of the design features found in modern luminaires. In general, a systems perspective is required to understand the reliability of these devices since LED failure is rare. In contrast, components such as drivers, lenses, and reflector are more likely to impact luminaire reliability than LEDs.

  9. Solid State Lighting LED Manufacturing Roundtable Summary

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2010-03-31

    Summary of a meeting of LED experts to develop proposed priority tasks for the Manufacturing R&D initiative, including task descriptions, discussion points, recommendations, and presentation highlights.

  10. LEDs: revolution or evolution? Part One

    Energy Technology Data Exchange (ETDEWEB)

    Roush, M.

    2000-11-01

    The historical evolution, the current state of light emitting diodes (LEDs), future implications and the promise of this technology for the lighting industry are explored. Some of the misconceptions relative to that promise are dispelled and some of the less obvious benefits that this technology could deliver in the future are discussed. As far as misconceptions are concerned, it is not true that LEDs will deliver light forever at a fraction of the energy of conventional light sources, or that they come in an infinite variety of colours and cost just pennies. Although LEDs per se may last a long time, the fact is that their true life expectancy is only as long as the wiring and the connection within the system, and they are certainly limited. Energy efficiency is another misconception. The truth is that white LEDs (the best for illumination purposes) are limited to less than 10 lumen per Watt, which is hardly a revolutionary improvement over incandescent light sources. Equally disappointing is the misconception concerning price. In actual fact, LEDs in lighting applications are very new and it would require mass production in the millions before LED lighting packages could become inexpensive. At the same time, LEDs have many advantages that are not commonly known. Compactness, very high level of light utilization, high life expectancy and nearly flat mortality curve are some of these. Operating on direct current lends LED installations to battery and solar applications (as for example solar LED road studs to aid in night driving). The absence of ultraviolet emissions in LEDs is another lesser known, but important feature, especially in applications where material degradation is a major concern (as in stores and museums). In general, all indicators point to a bright future for LEDs as their application progresses from decoration to illumination. This topic will be further explored in Part Two of this article. 4 figs.

  11. On the switching speed of SOI LEDs

    NARCIS (Netherlands)

    Schmitz, Jurriaan; de Vries, R.; Salm, Cora; Hoang, T.; Hueting, Raymond Josephus Engelbart; Holleman, J.

    2008-01-01

    Recently, we presented a novel design for a silicon LED in SmartCUT™ SOI wafers. It exhibits a record quantum efficiency for SOI-based silicon LEDs and opens the way to the integration of light emitters in a VLSI process on SOI. In this paper, we present first experimental and modeling results

  12. Led-licht biedt mogelijkheden in broeierij

    NARCIS (Netherlands)

    Neefjes, H.; PPO Bomen-bollen,

    2010-01-01

    Onderzoekers van PPO Lisse hebben de mogelijkheden van led-licht verkend bij met name lelie en tulp. Bij lelie bieden leds perspectief in de voortrek. Tulp kan er bijna de hele broeifase van profiteren. Veel licht is niet nodig, maar meerlagenteelt is een voorwaarde.

  13. Reduced Component Count RGB LED Driver

    NARCIS (Netherlands)

    De Pedro, I.; Ackermann, B.

    2008-01-01

    The goal of this master thesis is to develop new drive and contrololutions, for creating white light from mixing the light of different-color LEDs, aiming at a reduced component count resulting in less space required by the electronics and lower cost. It evaluates the LED driver concept proposed in

  14. Led Zeppelin reklaamib Narvat / Anti Ronk

    Index Scriptorium Estoniae

    Ronk, Anti

    2007-01-01

    Ilmus Narva-teemaline kahest CD-st koosnev album, kus ühel plaadil on 60 minutit videot linna vaatamisväärsuste ja informatsiooniga, teisel - briti rockansambli Led Zeppelini teosed Narva sümfooniaorkestri ja rockansambli Led R esituses

  15. Advances in LEDs for automotive applications

    Science.gov (United States)

    Bhardwaj, Jy; Peddada, Rao; Spinger, Benno

    2016-03-01

    High power LEDs were introduced in automotive headlights in 2006-2007, for example as full LED headlights in the Audi R8 or low beam in Lexus. Since then, LED headlighting has become established in premium and volume automotive segments and beginning to enable new compact form factors such as distributed low beam and new functions such as adaptive driving beam. New generations of highly versatile high power LEDs are emerging to meet these application needs. In this paper, we will detail ongoing advances in LED technology that enable revolutionary styling, performance and adaptive control in automotive headlights. As the standards which govern the necessary lumens on the road are well established, increasing luminance enables not only more design freedom but also headlight cost reduction with space and weight saving through more compact optics. Adaptive headlighting is based on LED pixelation and requires high contrast, high luminance, smaller LEDs with high-packing density for pixelated Matrix Lighting sources. Matrix applications require an extremely tight tolerance on not only the X, Y placement accuracy, but also on the Z height of the LEDs given the precision optics used to image the LEDs onto the road. A new generation of chip scale packaged (CSP) LEDs based on Wafer Level Packaging (WLP) have been developed to meet these needs, offering a form factor less than 20% increase over the LED emitter surface footprint. These miniature LEDs are surface mount devices compatible with automated tools for L2 board direct attach (without the need for an interposer or L1 substrate), meeting the high position accuracy as well as the optical and thermal performance. To illustrate the versatility of the CSP LEDs, we will show the results of, firstly, a reflector-based distributed low beam using multiple individual cavities each with only 20mm height and secondly 3x4 to 3x28 Matrix arrays for adaptive full beam. Also a few key trends in rear lighting and impact on LED light

  16. High Performance Green LEDs by Homoepitaxial

    Energy Technology Data Exchange (ETDEWEB)

    Wetzel, Christian; Schubert, E Fred

    2009-11-22

    This work's objective was the development of processes to double or triple the light output power from green and deep green (525 - 555 nm) AlGaInN light emitting diode (LED) dies within 3 years in reference to the Lumileds Luxeon II. The project paid particular effort to all aspects of the internal generation efficiency of light. LEDs in this spectral region show the highest potential for significant performance boosts and enable the realization of phosphor-free white LEDs comprised by red-green-blue LED modules. Such modules will perform at and outperform the efficacy target projections for white-light LED systems in the Department of Energy's accelerated roadmap of the SSL initiative.

  17. White LEDs with limit luminous efficacy

    Science.gov (United States)

    Lisitsyn, V. M.; Lukash, V. S.; Stepanov, S. A.; Yangyang, Ju

    2016-01-01

    In most promising widespread gallium nitride based LEDs emission is generated in the blue spectral region with a maximum at about 450 nm which is converted to visible light with the desired spectrum by means of phosphor. The thermal energy in the conversion is determined by the difference in the energies of excitation and emission quanta and the phosphor quantum yield. Heat losses manifest themselves as decrease in the luminous efficacy. LED heating significantly reduces its efficiency and life. In addition, while heating, the emission generation output and the efficiency of the emission conversion decrease. Therefore, the reduction of the energy losses caused by heating is crucial for LED development. In this paper, heat losses in phosphor-converted LEDs (hereinafter chips) during spectrum conversion are estimated. The limit values of the luminous efficacy for white LEDs are evaluated.

  18. White LEDs with limit luminous efficacy

    Energy Technology Data Exchange (ETDEWEB)

    Lisitsyn, V. M.; Stepanov, S. A., E-mail: stepanovsa@tpu.ru; Yangyang, Ju [National Research Tomsk Polytechnic University, 30 Lenin Av., Tomsk, 634050 (Russian Federation); Lukash, V. S. [JSC Research Institute of Semiconductor Devices, 99a Krasnoarmeyskaja St., Tomsk, 634050 (Russian Federation)

    2016-01-15

    In most promising widespread gallium nitride based LEDs emission is generated in the blue spectral region with a maximum at about 450 nm which is converted to visible light with the desired spectrum by means of phosphor. The thermal energy in the conversion is determined by the difference in the energies of excitation and emission quanta and the phosphor quantum yield. Heat losses manifest themselves as decrease in the luminous efficacy. LED heating significantly reduces its efficiency and life. In addition, while heating, the emission generation output and the efficiency of the emission conversion decrease. Therefore, the reduction of the energy losses caused by heating is crucial for LED development. In this paper, heat losses in phosphor-converted LEDs (hereinafter chips) during spectrum conversion are estimated. The limit values of the luminous efficacy for white LEDs are evaluated.

  19. Replacing Lecture with Peer-led Workshops Improves Student Learning

    OpenAIRE

    Preszler, Ralph W.

    2009-01-01

    Peer-facilitated workshops enhanced interactivity in our introductory biology course, which led to increased student engagement and learning. A majority of students preferred attending two lectures and a workshop each week over attending three weekly lectures. In the workshops, students worked in small cooperative groups as they solved challenging problems, evaluated case studies, and participated in activities designed to improve their general learning skills. Students in the workshop versio...

  20. Genesis of the rational «proof» for the existence of God in Xavier Zubiri in light of his last writings

    Directory of Open Access Journals (Sweden)

    Esteban Vargas

    2018-01-01

    Full Text Available This paper attempts to show how Zubiri was understanding and explaining his «proof» or argument for the existence of God from his last works. We study his proof through the «way of religation» from four texts or seminars: The theological problem of man: God, religion, Christianity (1971, The unfolding of the problem of God (1971-1973, published as a second part in Man and God, The theological problem of man: man and God (1973 and Sentient Intelligence (1980-1983.

  1. Design of an Oximeter Based on LED-LED Configuration and FPGA Technology

    OpenAIRE

    Stojanovic, Radovan; Karadaglic, Dejan

    2013-01-01

    A fully digital photoplethysmographic (PPG) sensor and actuator has been developed. The sensing circuit uses one Light Emitting Diode (LED) for emitting light into human tissue and one LED for detecting the reflectance light from human tissue. A Field Programmable Gate Array (FPGA) is used to control the LEDs and determine the PPG and Blood Oxygen Saturation (SpO2). The configurations with two LEDs and four LEDs are developed for measuring PPG signal and Blood Oxygen Saturation (SpO2). N-LEDs...

  2. White LED with High Package Extraction Efficiency

    International Nuclear Information System (INIS)

    Yi Zheng; Stough, Matthew

    2008-01-01

    The goal of this project is to develop a high efficiency phosphor converting (white) Light Emitting Diode (pcLED) 1-Watt package through an increase in package extraction efficiency. A transparent/translucent monolithic phosphor is proposed to replace the powdered phosphor to reduce the scattering caused by phosphor particles. Additionally, a multi-layer thin film selectively reflecting filter is proposed between blue LED die and phosphor layer to recover inward yellow emission. At the end of the project we expect to recycle approximately 50% of the unrecovered backward light in current package construction, and develop a pcLED device with 80 lm/W e using our technology improvements and commercially available chip/package source. The success of the project will benefit luminous efficacy of white LEDs by increasing package extraction efficiency. In most phosphor-converting white LEDs, the white color is obtained by combining a blue LED die (or chip) with a powdered phosphor layer. The phosphor partially absorbs the blue light from the LED die and converts it into a broad green-yellow emission. The mixture of the transmitted blue light and green-yellow light emerging gives white light. There are two major drawbacks for current pcLEDs in terms of package extraction efficiency. The first is light scattering caused by phosphor particles. When the blue photons from the chip strike the phosphor particles, some blue light will be scattered by phosphor particles. Converted yellow emission photons are also scattered. A portion of scattered light is in the backward direction toward the die. The amount of this backward light varies and depends in part on the particle size of phosphors. The other drawback is that yellow emission from phosphor powders is isotropic. Although some backward light can be recovered by the reflector in current LED packages, there is still a portion of backward light that will be absorbed inside the package and further converted to heat. Heat generated

  3. FREQUENCY CHARACTERISTICS OF MODERN LED PHOSPHOR MATERIALS

    Directory of Open Access Journals (Sweden)

    Maxim S. Fudin

    2014-11-01

    Full Text Available Frequency characteristics of modern LED phosphor materials have been considered for the purpose of assessing the prospects of phosphor-based LEDs in wireless communication data systems which use optical wavelengths. The measurements have been carried out on the dependence of the emission intensity of single LEDs and LED chip-on-board modules with phosphors based on yttrium-aluminum and lutetium-aluminum garnets (with or without addition of nitridebased phosphors as well as silicate-based phosphors, on the frequency of electric pulses exciting the emission. It was shown that from the point of view of data transmission rate, garnet-based phosphors (including systems with added nitride phosphors are more promising than silicate–based ones. Garnet-based materials can be used in optical communication data systems with bandwidth (without extra modulation applied up to 3 MHz with single–chip LEDs and up to 4.5 MHz with 9- chip LED chip-on-board modules. The results of the work indicate that a significant part of white LEDs used in general lighting systems can be even now used for data transfer, for example, in systems assisting positioning in closed spaces to facilitate people searching necessary rooms or objects

  4. High Power UV LED Industrial Curing Systems

    Energy Technology Data Exchange (ETDEWEB)

    Karlicek, Robert, F., Jr; Sargent, Robert

    2012-05-14

    UV curing is a green technology that is largely underutilized because UV radiation sources like Hg Lamps are unreliable and difficult to use. High Power UV LEDs are now efficient enough to replace Hg Lamps, and offer significantly improved performance relative to Hg Lamps. In this study, a modular, scalable high power UV LED curing system was designed and tested, performing well in industrial coating evaluations. In order to achieve mechanical form factors similar to commercial Hg Lamp systems, a new patent pending design was employed enabling high irradiance at long working distances. While high power UV LEDs are currently only available at longer UVA wavelengths, rapid progress on UVC LEDs and the development of new formulations designed specifically for use with UV LED sources will converge to drive more rapid adoption of UV curing technology. An assessment of the environmental impact of replacing Hg Lamp systems with UV LED systems was performed. Since UV curing is used in only a small portion of the industrial printing, painting and coating markets, the ease of use of UV LED systems should increase the use of UV curing technology. Even a small penetration of the significant number of industrial applications still using oven curing and drying will lead to significant reductions in energy consumption and reductions in the emission of green house gases and solvent emissions.

  5. Kansas highway LED illumination manual : a guide for the use of LED lighting systems.

    Science.gov (United States)

    2015-12-01

    The research project was aimed to assist the Kansas Department of Transportation (KDOT) in the development of a Highway LED Illumination Manual for guiding the upcoming implementation of successful LED roadway lighting systems in Kansas to replace th...

  6. Kansas highway LED illumination manual : a guide for the use of LED lighting systems : [technical summary].

    Science.gov (United States)

    2015-12-01

    The research project was aimed to assist the Kansas Department of Transportation (KDOT) in the development of a Highway LED Illumination Manual for guiding the upcoming implementation of successful LED roadway lighting systems in Kansas to replace th...

  7. LED traffic signal management system : final report.

    Science.gov (United States)

    2016-06-01

    This research originated from the opportunity to develop a methodology to assess when LED (Light Emitting Diode) traffic signal modules begin to fail to meet the Institute of Transportation Engineers (ITE) performance specification for luminous inten...

  8. Significant growth in. LED use predicted.

    Science.gov (United States)

    Simpson, Mike

    2012-03-01

    Although LED lighting has its critics, a number of whom (see article 'LED--panacea or marketing hype', HEJ--February 2012) are concerned about what they claim are some manufacturers' 'exaggerated claims' about lighting efficiency and lamp lifetime, Philips Lighting believes that, such are the advances being made in this innovative lighting technology, that LED's overall share of the European lighting market will have risen from around 7% in 2008 to 25% by 2020 and that, a decade later, it will account for a remarkable 75% of lighting sales. In the UK, Philips' technical and design director for Lighting, Mike Simpson, told HEJ editor, Jonathan Baillie, healthcare estates and facilities managers are increasingly recognising the potential to save energy, reduce carbon emissions, and cut maintenance costs, using LED.

  9. LED til væksthuse

    DEFF Research Database (Denmark)

    Dam-Hansen, Carsten; Thorseth, Anders; Rosenqvist, Eva

    2012-01-01

    Den teknologiske udvikling indenfor Lys Emitterende Dioder (LED) går imod stadig større lysmængder og stadig større effektivitet. Kombineret med fordele som lang levetid, dæmpbarhed og ingen varmestråling gør det, at LED baserede lyskilder/lamper i stigende grad benyttes til belysningsformål og kan...

  10. LED Shipboard Lighting: A Comparative Analysis

    Science.gov (United States)

    2009-12-01

    viability of retrofitting the Navy fleet with newer lighting technology . C. RESEARCH QUESTION The research project provided to NPS by Dr. Larry Schuette...LED is a key component in today’s lighting technology . Modern households use LEDs in such components as digital video disc, (DVD) readers...manufactures that the Navy is serious in implementing lighting technology with a multi- year demonstration seeing the benefits provided by the manufactures

  11. LEDS GP Success Story: Fostering Coordinated LEDS Support in Kenya (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2014-03-01

    The LEDS Global Partnership (LEDS GP) strives to advance climate-resilient, low-emission development through catalyzing collaboration, information exchange, and action on the ground. The Government of Kenya is a key LEDS GP member and offers an inspiring example of how LEDS GP is having an impact globally. The 2012 LEDS Collaboration in Action workshop in London provided an interactive space for members to share experiences on cross-ministerial LEDS leadership and to learn about concrete development impacts of LEDS around the world. Inspired by these stories, the Kenya's Ministry of State for Planning, National Development and Vision 2030 (MPND) began to collaborate closely with the Ministry of Environment and Mineral Resources to create strong links between climate change action and development in the country, culminating in the integration of Kenya's National Climate Change Action Plan and the country's Medium Term Development Plan.

  12. O processo sucessório em propriedades de produtores de leite nos municípios de Coronel Xavier Chaves e Silveirânia, em Minas Gerais

    Directory of Open Access Journals (Sweden)

    Júlio César Mendes de Souza

    2013-10-01

    Full Text Available O objetivo deste estudo foi identificar os fatores que influenciam a presença de sucessores, em unidades familiares de produção de leite nos Municípios de Coronel Xavier Chaves e Silveirânia, em Minas Gerais. Utilizou-se, como referencial teórico, a influência dos valores tradicionais, e daqueles relacionados com a modernidade, no processo sucessório. Tomou-se, como hipótese, o fato de que o nível tecnológico, o tamanho da propriedade, o acesso ao crédito, a proximidade com o centro urbano e a escolaridade poderiam influenciar a presença do sucessor nas unidades produtoras de leite. Em termos de procedimentos metodológicos, trabalhou-se, nesta pesquisa, com a perspectiva comparativa entre produtores de leite de dois municípios mineiros que apresentavam níveis tecnológicos diferentes, entre si. Utilizou-se o método de levantamento com coleta de dados em campo, por meio da aplicação de 83 questionários semiestruturados a uma amostra de produtores de leite de caráter familiar. Para análise dos dados, utilizaram-se os testes t, qui-quadrado e de regressão. Os resultados não confirmaram a hipótese de que o nível de tecnologia seria fator interveniente no processo sucessório entre produtores de leite, porém se confirmaram as outras quatro hipóteses.

  13. Affordable underwater wireless optical communication using LEDs

    Science.gov (United States)

    Pilipenko, Vladimir; Arnon, Shlomi

    2013-09-01

    In recent years the need for high data rate underwater wireless communication (WC) has increased. Nowadays, the conventional technology for underwater communication is acoustic. However, the maximum data rate that acoustic technology can provide is a few kilobits per second. On the other hand, emerging applications such as underwater imaging, networks of sensors and swarms of underwater vehicles require much faster data rates. As a result, underwater optical WC, which can provide much higher data rates, has been proposed as an alternative means of communication. In addition to high data rates, affordable communication systems become an important feature in the development requirements. The outcome of these requirements is a new system design based on off-the-shelf components such as blue and green light emitting diodes (LEDs). This is due to the fact that LEDs offer solutions characterized by low cost, high efficiency, reliability and compactness. However, there are some challenges to be met when incorporating LEDs as part of the optical transmitter, such as low modulation rates and non linearity. In this paper, we review the main challenges facing the incorporation of LEDs as an integral part of underwater WC systems and propose some techniques to mitigate the LED limitations in order to achieve high data rate communication

  14. Design of LED projector based on gradient-index lens

    Science.gov (United States)

    Qian, Liyong; Zhu, Xiangbing; Cui, Haitian; Wang, Yuanhang

    2018-01-01

    In this study, a new type of projector light path is designed to eliminate the deficits of existing projection systems, such as complex structure and low collection efficiency. Using a three-color LED array as the lighting source, by means of the special optical properties of a gradient-index lens, the complex structure of the traditional projector is simplified. Traditional components, such as the color wheel, relay lens, and mirror, become unnecessary. In this way, traditional problems, such as low utilization of light energy and loss of light energy, are solved. With the help of Zemax software, the projection lens is optimized. The optimized projection lens, LED, gradient-index lens, and digital micromirror device are imported into Tracepro. The ray tracing results show that both the utilization of light energy and the uniformity are improved significantly.

  15. Zernike polynomials for photometric characterization of LEDs

    International Nuclear Information System (INIS)

    Velázquez, J L; Ferrero, A; Pons, A; Campos, J; Hernanz, M L

    2016-01-01

    We propose a method based on Zernike polynomials to characterize photometric quantities and descriptors of light emitting diodes (LEDs) from measurements of the angular distribution of the luminous intensity, such as total luminous flux, BA, inhomogeneity, anisotropy, direction of the optical axis and Lambertianity of the source. The performance of this method was experimentally tested for 18 high-power LEDs from different manufacturers and with different photometric characteristics. A small set of Zernike coefficients can be used to calculate all the mentioned photometric quantities and descriptors. For applications not requiring a great accuracy such as those of lighting design, the angular distribution of the luminous intensity of most of the studied LEDs can be interpolated with only two Zernike polynomials. (paper)

  16. White LED phosphors: the next step

    Science.gov (United States)

    Yamamoto, Hajime

    2010-02-01

    Application of white LEDs is extended toward high-output light sources, e.g. for automotive headlights, and better spectral matching with optical filters for LCD backlighting. To meet such new demands, phosphor materials have been investigated with focus on their luminescence spectra, temperature characteristics and reliability. The conventional yellow phosphor based on Y3Al5O12:Ce3+ has excellent performance as a single phosphor combined with a blue LED. More recently developed nitrido- or oxonitrido-silicates activated with Eu2+ are also promising materials showing green to red luminescence depending on a composition and high thermal and chemical stability. And yet, demands for specific application have been made clear and strong. This paper reviews the present status and challenging goals of phosphors in the next stage further to make progress in white LEDs.

  17. LED module with high index lens

    Energy Technology Data Exchange (ETDEWEB)

    Bierhuizen, Serge J.; Wang, Nanze Patrick; Eng, Gregory W.; Sun, Decai; Wei, Yajun

    2017-09-05

    An array of housings with housing bodies and lenses is molded, or an array of housing bodies is molded and bonded with lenses to form an array of housings with housing bodies and lenses. Light-emitting diodes (LEDs) are attached to the housings in the array. An array of metal pads may be bonded to the back of the array or insert molded with the housing array to form bond pads on the back of the housings. The array is singulated to form individual LED modules.

  18. Intelligent styring af dynamisk LED belysning

    DEFF Research Database (Denmark)

    Thorseth, Anders; Corell, Dennis Dan; Hansen, Søren Stentoft

    Denne slutrapport giver en kort beskrivelse af arbejdet, der er udført af DTU Fotonik i projektet ”Intelligent styring af dynamisk LED belysning” støttet af EUDP. Arbejdet er udført i perioden 2011‐2012 i samarbejde med Lighten.......Denne slutrapport giver en kort beskrivelse af arbejdet, der er udført af DTU Fotonik i projektet ”Intelligent styring af dynamisk LED belysning” støttet af EUDP. Arbejdet er udført i perioden 2011‐2012 i samarbejde med Lighten....

  19. Final report LED solutions for public lighting; Eindrapportage LED oplossingen voor openbare verlichting

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-04-15

    This report examines if and how LED can be used for public lighting on a large scale. Pilot projects in 29 municipalities were assessed to test the usefulness of LED lighting. This final report provides answers to the questions that relate to the feasibility of the deployment of LED in public lighting and provides some practical pointers. [Dutch] Er is onderzocht of, en zo ja op welke wijze, LED grootschalig toegepast kan worden in de openbare verlichting (OVL). In 29 gemeenten in Nederland zijn proefprojecten geevalueerd om LED verlichting te toetsen op bruikbaarheid. Deze eindrapportage geeft antwoord op vragen die betrekking hebben op de haalbaarheid van de toepassing van LED binnen de OVL en geeft wat praktische aandachtspunten.

  20. Design of an oximeter based on LED-LED configuration and FPGA technology.

    Science.gov (United States)

    Stojanovic, Radovan; Karadaglic, Dejan

    2013-01-04

    A fully digital photoplethysmographic (PPG) sensor and actuator has been developed. The sensing circuit uses one Light Emitting Diode (LED) for emitting light into human tissue and one LED for detecting the reflectance light from human tissue. A Field Programmable Gate Array (FPGA) is used to control the LEDs and determine the PPG and Blood Oxygen Saturation (S(p)O(2)). The configurations with two LEDs and four LEDs are developed for measuring PPG signal and Blood Oxygen Saturation (S(p)O(2)). N-LEDs configuration is proposed for multichannel S(p)O(2) measurements. The approach resulted in better spectral sensitivity, increased and adjustable resolution, reduced noise, small size, low cost and low power consumption.

  1. Design of an Oximeter Based on LED-LED Configuration and FPGA Technology

    Directory of Open Access Journals (Sweden)

    Radovan Stojanovic

    2013-01-01

    Full Text Available A fully digital photoplethysmographic (PPG sensor and actuator has been developed. The sensing circuit uses one Light Emitting Diode (LED for emitting light into human tissue and one LED for detecting the reflectance light from human tissue. A Field Programmable Gate Array (FPGA is used to control the LEDs and determine the PPG and Blood Oxygen Saturation (SpO2. The configurations with two LEDs and four LEDs are developed for measuring PPG signal and Blood Oxygen Saturation (SpO2. N-LEDs configuration is proposed for multichannel SpO2 measurements. The approach resulted in better spectral sensitivity, increased and adjustable resolution, reduced noise, small size, low cost and low power consumption.

  2. LEDs/ALAN-Working To Be Good Neighbors

    Science.gov (United States)

    Adams, Robert

    2015-08-01

    ALAN (Artificial Light At Night) and LEDs have recently become major discussion topics in the areas of astronomy, light pollution, endangered species and human health to mention but a few. In years past, MH, LPS and HPS dominated night lighting with LPS and its associated narrow spectrum as the preferred source around observatories and shorelines. LEDs offer the ability to modify the spectrum, realize substantial energy savings and other associated benefits while meeting the requirements of the astronomy community.The primary concern of the different groups relates to blue light content of the LED. For astronomers, the molecular (Raleigh) scattering related to the blue light interferes with certain portions of the spectrum used for deep space studies. The ecologists studying various endangered species find blue and green light can be related to declining leatherback turtle population in certain areas of the world. Other animals ranging from bats to moths and other insects are now being studied to determine the effect of the blue light spectrum on their behavior. The impact of blue light on the human circadian rhythm and vision, especially in the older population, is being extensively studied today.This presentation will discuss the spectral power distribution (SPD) of various light sources, the performance of new LED solutions and how the SPD of these new LED’s can be adapted to address some of the issues raised by various constituencies. A discussion describing why some of the metrics used to describe standard lighting are not adequate for specifying the new LED solutions with the modified spectra will be included.Today, lighting plans and implementation are all too often based on opinions and limited data. The ensuing problems and repercussions make it imperative to collect accurate and thorough information. Data collection is now ongoing using a variety of techniques analyzing the “before” and “after” lighting results from the C of HI LED streetlight

  3. LED structure with enhanced mirror reflectivity

    Science.gov (United States)

    Bergmann, Michael; Donofrio, Matthew; Heikman, Sten; Schneider, Kevin S; Haberern, Kevin W; Edmond, John A

    2014-04-01

    Embodiments of the present invention are generally related to LED chips having improved overall emission by reducing the light-absorbing effects of barrier layers adjacent mirror contacts. In one embodiment, a LED chip comprises one or more LEDs, with each LED having an active region, a first contact under the active region having a highly reflective mirror, and a barrier layer adjacent the mirror. The barrier layer is smaller than the mirror such that it does not extend beyond the periphery of the mirror. In another possible embodiment, an insulator is further provided, with the insulator adjacent the barrier layer and adjacent portions of the mirror not contacted by the active region or by the barrier layer. In yet another embodiment, a second contact is provided on the active region. In a further embodiment, the barrier layer is smaller than the mirror such that the periphery of the mirror is at least 40% free of the barrier layer, and the second contact is below the first contact and accessible from the bottom of the chip.

  4. LED Lighting in a Performing Arts Building

    Energy Technology Data Exchange (ETDEWEB)

    Miller, N. J.; Kaye, S. M. [Univ. of Florida, Gainesville, FL (United States); Coleman, P. M. [Univ. of Florida, Gainesville, FL (United States); Wilkerson, A. M.; Perrin, T. E.; Sullivan, G. P. [Efficiency Solutions, Inc., Richland, WA (United States)

    2014-07-31

    At the University of Florida in Gainesville, the DOE Solid-State Lighting GATEWAY program evaluated LED architectural and theatrical lighting in four academic/performance-related spaces within the Nadine McGuire Theatre + Dance Pavilion. Due to a wise choice of products and luminaire light distributions, the change brought significant quality improvements including improved controllability and color.

  5. Preliminary investigations of piezoelectric based LED luminary

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Andersen, Michael A. E.; Meyer, Kaspar Sinding

    2011-01-01

    This paper presents a preliminary study of PT (Piezoelectric Transformer) based SMPS’s (Switch Mode Power Supplies) for LED luminary. The unique properties of PTs (efficiency, power density and EMI) make them highly suitable for this application. Power stage topologies, rectifiers circuits...

  6. Photobiocatalytic alcohol oxidation using LED light sources

    NARCIS (Netherlands)

    Rauch, M.C.R.; Schmidt, S.; Arends, I.W.C.E.; oppelt, K.; Kara, S; Hollmann, F.

    2016-01-01

    The photocatalytic oxidation of NADH using a flavin photocatalyst and a simple blue LED light source is reported. This in situ NAD+ regeneration system can be used to promote biocatalytic, enantioselective oxidation reactions. Compared to the traditional use of white light bulbs this method enables

  7. NASA Ames UV-LED Poster Overview

    Science.gov (United States)

    Jaroux, Belgacem Amar

    2015-01-01

    UV-LED is a small satellite technology demonstration payload being flown on the Saudisat-4 spacecraft that is demonstrating non-contacting charge control of an isolated or floating mass using new solid-state ultra-violet light emitting diodes (UV-LEDs). Integrated to the rest of the spacecraft and launched on a Dnepr in June 19, 2014, the project is a collaboration between the NASA Ames Research Center (ARC), Stanford University, and King Abdulaziz City for Science and Technology (KACST). Beginning with its commissioning in December, 2015, the data collected by UV-LED have validated a novel method of charge control that will improve the performance of drag-free spacecraft allowing for concurrent science collection during charge management operations as well as reduce the mass, power and volume required while increasing lifetime and reliability of a charge management subsystem. UV-LED continues to operate, exploring new concepts in non-contacting charge control and collecting data crucial to understanding the lifetime of ultra-violet light emitting diodes in space. These improvements are crucial to the success of ground breaking missions such as LISA and BBO, and demonstrates the ability of low cost small satellite missions to provide technological advances that far exceed mission costs.

  8. Child-Led Enquiry in Primary Science

    Science.gov (United States)

    Dunlop, Lynda; Compton, Kirsty; Clarke, Linda; McKelvey-Martin, Valerie

    2015-01-01

    This research describes and evaluates the application of a child-led approach to scientific enquiry (the Community of Scientific Enquiry, CoSE) to children aged 8-11 (Key Stage 2) in Northern Ireland. Primary teachers were introduced to CoSE at a workshop and asked to evaluate its implementation with their class. Results from children (n = 364)…

  9. LED light recycling using double prisms

    Science.gov (United States)

    Ouyang, George; Li, Kenneth

    2013-09-01

    A novel LED recycling scheme using double prisms is presented. Two identical triangular prisms with square bases, one cross-stacked on top of the other, are tight-fit into a mirrored light tunnel. The whole prism/light tunnel assembly is then mounted on top of a square LED source, whose emitting area is the same as that of the base plane of the said prism/light tunnel assembly. Each prism acts as a tapered-down light guide in one dimension, which selectively retro-reflects high angle light along that direction. The outer light tunnel serves as a mirrored wall that folds back any light that escapes outside the two prisms. For a given collection cone angle, the height of the two prisms is optimized using ASAP, a commercial ray-tracing software. Simulation and experimental results show promise in significantly increasing the brightness of the LED sources within the collection cone. Specifically for a 4x recycling ratio a 70% recycling gain in center illuminance has been achieved (i.e., illuminance measured in the forward direction). This scheme has advantages over previous recycling configurations due to its compactness and ease of mounting. For example, compared to Wavien's spherical reflector approach that has been previously published, the current recycling configuration is much smaller in size because instead of fitting a much larger mirrored reflector on top of the LED source, this time we're using a structure that has the same lateral dimensions as those of the LED source itself. Further improvement is also possible if optimization of various system parameters is carried out.

  10. Influence of variation of electrical parameters values of RGB LEDs on the radiation uniformity of LED displays at minimal luminosity grade

    Directory of Open Access Journals (Sweden)

    Veleschuk V. P.

    2017-06-01

    Full Text Available The emission uniformity of LED chips in the entire range of brightness and colors is the problem in LED displays manufacture process. It was approved that at lowering brightness gradations appearing the radiation nonuniformity between LED chips, and the higher disorders will be seen on the lesser emission levels. The RGB LED chips, observed by us, were based on AlGaInP (red, In0.3Ga0.7N/GaN (green, and In0,2Ga0,8NN/ GaN (blue and had nominal working current 20 mA. Analysis of the current-voltage characteristics and capacitance-voltage characteristics showed the presence of inhomogeneous semiconductor junctions and ohmic contacts in blue LEDs structures that are the source of possible irregularities in the final emission of LED displays. The variation of voltages (at current 10 mA were 2.81—2.98 V for blue structures, and 1.9—2.0 V for red ones. Some of the blue structures had additional parasite current-flow mechanism at low current. Rise time and fall time of electroluminescence pulse of blue structures were measured. The shortest LED pulse time in LED displays is limited by duration of 6—8 ns. The quality of LED displays may be improved by implementating the preliminary control of LED chips in a narrower range of voltage variation at operating currents, or more narrow interval of I—V variation. This additional LEDs sorting will of course reduce the percentage of the total amount of light-emitting diodes, but may improve the image (video, photo quality at translations by using a lower brightness gradations.

  11. CooLED - efficient LED bulbs with custrom optics - final report

    DEFF Research Database (Denmark)

    Wolff, Jesper; Corell, Dennis Dan; Dam-Hansen, Carsten

    Denne rapport indeholder en beskrivelse af arbejdet udført i og resultaterne af forsknings- og udviklingsprojektet EUDP 64012-0226, CooLED – en ny generation LED Lyskilde for det tidsløse high-end marked....

  12. Sustainable LED Fluorescent Light Replacement Technology

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2011-09-30

    Ilumisys and the National Center for Manufacturing Sciences (NCMS) partnered on a three-year project awarded by the United States (U.S.) Department of Energy (DOE), to quantify the impacts of LED lamps, incandescent lamps and fluorescent benchmark lamps over a product lifecycle – i.e. to develop a sustainable design and manufacturing strategy that addresses product manufacturing, use, recycling and disposal scenarios for LED-based lighting. Based on the knowledge gained from extensive product tear-down studies of fluorescent and screw-in lighting products, lifecycle assessment tools, and accelerated lifecycle testing protocols, an interactive Sustainable LED Design Guide has been developed to aid architectural and lighting designers and engineers in making design decisions that consider three important environmental impacts (greenhouse gas emissions, energy use and mercury emission) across all phases of the life of an LED lighting product. Critical information developed for the lifecycle analysis and product feature comparisons is the useful life of the lighting product as well as its performance. The Design Guide is available at www.ncms.org, and was developed based on operational and durability testing of a variety of lighting products including power consumption, light output, and useful life of a lamp in order to allow a more realistic comparison of lamp designs. This report describes the main project tasks, results and innovative features of the lifecycle assessment (LCA)-based design tools, and the key considerations driving the sustainable design of LED lighting systems. The Design Guide incorporates the following three novel features for efficiently evaluating LED lighting features in value-chains: Bill-of-Materials (BOM) Builder – Designers may import process data for each component and supply functional data for the product, including power, consumption, lumen output and expected useful life: Environmental Impact Review – Designs are comparable

  13. Low-Cost Illumination-Grade LEDs

    Energy Technology Data Exchange (ETDEWEB)

    Epler, John [Philips Lumileds Lighting Company LLC, San Jose, CA (United States)

    2013-08-31

    Solid State Lighting is a cost-effective, energy-conserving technology serving a rapidly expand- ing multi-billion dollar market. This program was designed to accelerate this lighting revolution by reducing the manufacturing cost of Illumination-Grade LEDs. The technical strategy was to investigate growth substrate alternatives to standard planar sapphire, select the most effective and compatible option, and demonstrate a significant increase in Lumen/$ with a marketable LED. The most obvious alternate substrate, silicon, was extensively studied in the first two years of the program. The superior thermal and mechanical properties of Si were expected to improve wavelength uniformity and hence color yield in the manufacture of high-power illumination- grade LEDs. However, improvements in efficiency and epitaxy uniformity on standard c-plane sapphire diminished the advantages of switching to Si. Furthermore, the cost of sapphire decreased significantly and the cost of processing Si devices using our thin film process was higher than expected. We concluded that GaN on Si was a viable technology but not a practical option for Philips Lumileds. Therefore in 2012 and 2013, we sought and received amendments which broadened the scope to include other substrates and extended the time of execution. Proprietary engineered substrates, off-axis (non-c-plane) sapphire, and c-plane patterned sapphire substrates (PSS) were all investigated in the final 18 months of this program. Excellent epitaxy quality was achieved on all three candidates; however we eliminated engineered substrates and non-c-plane sapphire because of their higher combined cost of substrate, device fabrication and packaging. Ultimately, by fabricating a flip-chip (FC) LED based upon c-plane PSS we attained a 42% reduction in LED manufacturing cost relative to our LUXEON Rebel product (Q1-2012). Combined with a flux gain from 85 to 102 Lm, the LUXEON Q delivered a 210% increase in Lm/$ over this time period. The

  14. Lifetime prediction of LED lighting systems considering thermal coupling between LED sources and drivers

    DEFF Research Database (Denmark)

    Alfarog, Azzarn Orner; Qu, Xiaohui; Wang, Huai

    2017-01-01

    The lifetime prediction of LED lighting system is important to guide the designers to fulfill the design specifications and to benchmark the cost-competitiveness of different lighting technologies. Currently, the lifetime of LED system is usually predicted from the source part and the driver part...... separately, and then the thermal design is also optimized independently. In practice, the LED source and driver are usually compacted in a single fixture. The heat dissipated from LED source and driver will be coupled together and affect the heat transfer performance, which may degrade the whole system...... and accelerate the failure. In this paper, a new thermal model concerning the thermal coupling is proposed with Finite Element Method (FEM) simulation for parameter acquirement. The proposed model has a better estimation of the thermal stresses of key components in the LED lamps and therefore an improved...

  15. Tulane/Xavier University hazardous materials in aquatic environments of the Mississippi River basin. Quarterly progress report, January 1--March 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-17

    The objectives of this report are to provide the necessary administrative support to assure that the scientific and educational goals of the project are obtained and to assure that all Department of Energy reporting requirements and requests are fulfilled. The grant reporting is divided into three aspects: Collaborative Cluster projects, Initiation projects and Education projects. A cluster project is one or more closely related collaborative, multidisciplinary research projects in which a group of investigators employs a synergistic approach to the solution of problems in the same general area of research. The accomplishments this quarter of eleven cluster projects are presented. An initial project typically involves a single investigator. The purpose of the project is to undertake pilot work, lasting no more than one year, which will lead to the successful submission of an externally-funded proposal or the development of a collaborative cluster project. The accomplishments this quarter of eleven initiation projects are presented. The education projects are designed to develop courses with emphasis on environmental studies and/or to train students in areas of environmental research.

  16. LED i Københavns Kommunes gadebelysning

    DEFF Research Database (Denmark)

    Bülow, Katja

    2016-01-01

    Artiklen i denne udgivelse formidler resultatet af en undersøgelse, hvor de visuelle forhold i Københavns Kommunes gader undersøges som resultat af gadens belysning. Der lægges vægt på metoden bag undersøgelsen og på hvordan indførelsen af LED forandrer belysningen i gaderne.......Artiklen i denne udgivelse formidler resultatet af en undersøgelse, hvor de visuelle forhold i Københavns Kommunes gader undersøges som resultat af gadens belysning. Der lægges vægt på metoden bag undersøgelsen og på hvordan indførelsen af LED forandrer belysningen i gaderne....

  17. EVALUATING THE CULTURE-LED REGENERATION

    Directory of Open Access Journals (Sweden)

    D'Angelo Francesca

    2010-12-01

    Full Text Available The aim of the paper is to propose a new approach to urban planning, evaluating the culture-led regeneration processes. In the last few years, the cultural turn in urban planning played a central role in the urban studies. In this way we try to elaborate a more robust perspective interpreting the complex phenomenology emerging from the culture-led regeneration processes. Within the concept of complexity we discuss about the metabolic process that are the processes necessary to transform energy, material and information in goods and service functional to the complex urban system life. The approach that will be employed is the MuSIASEM that is based on several novel concept and an innovative methods never applied in this research field.

  18. Uniform LED illuminator for miniature displays

    Science.gov (United States)

    Medvedev, Vladimir; Pelka, David G.; Parkyn, William A.

    1998-10-01

    The Total Internally Reflecting (TIR) lens is a faceted structure composed of prismatic elements that collect a source's light over a much larger angular range than a conventional Fresnel lens. It has been successfully applied to the efficient collimation of light from incandescent and fluorescent lamps, and from light-emitting diodes (LEDs). A novel LED-powered collimating backlight is presented here, for uniformly illuminating 0.25'-diagonal miniature liquid- crystal displays, which are a burgeoning market for pagers, cellular phones, digital cameras, camcorders, and virtual- reality displays. The backlight lens consists of a central dual-asphere refracting section and an outer TIR section, properly curved with a curved exit face.

  19. Notes on LED Installations in Street Illumination

    Directory of Open Access Journals (Sweden)

    Elisabeta Spunei

    2014-09-01

    Full Text Available The paper presents a study made on choosing LED street lighting installations, such that the quality requirements for exterior artificial lighting are fulfilled. We analyze two types of LED street lighting installations from a technical point of view, together with lighting level and brightness values obtained during the measurements. Following on the field measurements, the lighting quality parameters are calculated, and, for the lighting installation with the best performance, optimal mounting suggestions are made. The optimal quality parameters are calculated by simulations using the Dialux software. The same software and the same light sources we also compute an optimal street lighting by determining the size of the installation that provides the best lighting parameter values.

  20. Optical design of a LED searchlight system

    Science.gov (United States)

    Gong, Chen; Xu, Haiping; Liang, Jinhua; Liu, Yunfei; Yuan, Zengquan

    2018-01-01

    A 1200m visible searchlight system is designed based on photometry and application of geometric optics. To generate intensity distribution of this relatively powerful light beam we propose to use a high power LED and several refractive optical elements, which are composed of two plane-convex lenses and a conventional Fresnel lens. Two plane-convex lenses enable refraction of the side rays from the LED to the front direction which incident on the Fresnel lens. Fresnel lens, in its turn, concentrate the light flux and provide a nearly collimated beam to meet the requirement of forming a well-illuminated area across the road in the far field. Simulation data shows that this searchlight allow generating an appropriate illumination distribution for the long range requirements. A proof-of-concept prototype producing acceptable illuminance is developed.

  1. Distributed dimming control for LED lighting.

    Science.gov (United States)

    Lee, Sang Hyun; Kwon, Jae Kyun

    2013-11-04

    This paper presents a distributed energy-saving lighting strategy for the arrangements of a lighting network consisting of a group of light-emitting diode (LED) lamps and users. LED lamps have a dimming support feature to meet the illuminance requirements imposed by individual users. Both groups interact with each other via visible light communication (VLC) or other wireless communication features. This work aims to identify a configuration of lamps leading to the maximal energy saving in adaptive and distributed ways. To this end, a distributed assignment strategy is developed based on a message-passing framework where only local interactions among lamps and users are allowed for calculations and exchanges of the information on their status. The simulation results show that the proposed algorithm outperforms other distributed algorithms in a range of indoor lighting configurations.

  2. Youth-Led Participatory Action Research: Developmental and Equity Perspectives.

    Science.gov (United States)

    Ozer, Emily J

    2016-01-01

    Youth-led participatory action research (YPAR) is an approach to scientific inquiry and social change grounded in principles of equity that engages young people in identifying problems relevant to their own lives, conducting research to understand the problems, and advocating for changes based on research evidence. This chapter provides an introduction to YPAR followed by consideration of the (a) developmental relevance of YPAR for marginalized youth, (b) implications of YPAR for developmental science research on inequities experienced by youth, and (c) potential opportunities and impact of YPAR for improving key developmental settings such as schools and youth-serving organizations. Resources for conducting YPAR projects are discussed, as well as the need for potential integration of YPAR and other participatory approaches to engaging youth and their expertise-at a significant enough scale to have a meaningful impact on policies and practices that affect youth development. © 2016 Elsevier Inc. All rights reserved.

  3. Lampu Pintar Berbasis LED Dengan Multi Sensor

    OpenAIRE

    Ramdan, Ade; Prajitno, Dicky Rianto; Herlan, Herlan; Gojali, Elli Ahmad

    2013-01-01

    In this paper, we propose a LED-based smart lamp prototype that integrated with sensor. The smart lamp use information of people and lighting confirmation, to turn on or turn off the lamp automatically. In addition, the sensor calculates and balances flash and ambient light exposure to decrease the light, so that can make energy efficiently in use. PIR (Passive Infrared Receiver) and Ultrasonic sensor is preferred to detect people condition in one place and LDR (Light Dependent Resistant) is ...

  4. Preliminary investigations of piezoelectric based LED luminary

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Andersen, Michael A. E.; Meyer, Kaspar Sinding

    2011-01-01

    This paper presents a preliminary study of PT (Piezoelectric Transformer) based SMPS’s (Switch Mode Power Supplies) for LED luminary. The unique properties of PTs (efficiency, power density and EMI) make them highly suitable for this application. Power stage topologies, rectifiers circuits, modul....... The prototype constitutes a light source equivalent to the 40 W incandescent bulb. Experimental results shows, that the prototype are capable of ZVS and dimming (the later trough use of burst mode control)....

  5. UV LED lighting for automated crystal centring

    International Nuclear Information System (INIS)

    Chavas, Leonard M. G.; Yamada, Yusuke; Hiraki, Masahiko; Igarashi, Noriyuki; Matsugaki, Naohiro; Wakatsuki, Soichi

    2011-01-01

    A low-cost light-emitting diode (LED) UV source has been developed for facilitating macromolecular sample centring in the X-ray beam. A direct outcome of the exponential growth of macromolecular crystallography is the continuously increasing demand for synchrotron beam time, both from academic and industrial users. As more and more projects entail screening a profusion of sample crystals, fully automated procedures at every level of the experiments are being implemented at all synchrotron facilities. One of the major obstacles to achieving such automation lies in the sample recognition and centring in the X-ray beam. The capacity of UV light to specifically react with aromatic residues present in proteins or with DNA base pairs is at the basis of UV-assisted crystal centring. Although very efficient, a well known side effect of illuminating biological samples with strong UV sources is the damage induced on the irradiated samples. In the present study the effectiveness of a softer UV light for crystal centring by taking advantage of low-power light-emitting diode (LED) sources has been investigated. The use of UV LEDs represents a low-cost solution for crystal centring with high specificity

  6. Export-led Growth Hypothesis: Turkey Application

    Directory of Open Access Journals (Sweden)

    İsmail KÜÇÜKAKSOY

    2015-12-01

    Full Text Available This paper aims to investigate validity of “Export-led Growth Hypothesis” for Turkey using quarterly data in period from 2003:Q1 to 2015:Q1. Hypothesis argues that there is causality relationship from real export to real Gross Domestic Product (GDP. Johansen cointegration test, Gregory-Hansen cointegration test, Toda-Yamamoto causality test, Fully Modified Ordinary Least Squares (FMOLS, Canonical cointegrating regression (CCR and Dynamic ordinary least squares (DOLS methods were used in this study. Findings can be summarized as follows: a According to Johansen cointegration test there is no relationship among variables in the long-run whereas Gregory-Hansen cointegration test has determined relationship in the long-run; b According to Toda-Yamamoto causality test there is bidirectional causality between real export and real GDP. This finding proves the validity of “Export-led Growth Hypothesis” for Turkey; c According to FMOLS, CCR, DOLS methods a 1% increase in the real export increases the real GDP by 1.5195%, 1.5552%, 1.3171% respectively in the long-run. These methods prove the validity of “Export-led Growth Hypothesis” for Turkey.

  7. Tulane/Xavier Universities hazardous materials in aquatic environments of the Mississippi River Basin. Quarterly progress report, October 1, 1995--December 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    To provide the necessary administrative support to assure that the scientific and educational goals of the project are obtained and to assure that all Department of Energy reporting requirements and requests are fulfilled.The grant reporting is divided into three aspects: Collaborative Cluster projects, Initiation projects and Education projects. A cluster project is one or more closely related collaborative, multidisciplinary research projects in which a group of investigators employs a synergistic approach to the solution of problems in the same general area of research. An initiation project typically involves a single investigator. The purpose of the project is to undertaken pilot work, lasting no more than one year, which will lead to the successful submission of an externally-funded proposal or the development of a collaborative cluster project. The education projects are designed to develop courses with emphasis on environmental studies and/or to train students in areas of environmental research. Accomplishments this quarter are: (1) Issued a request for proposals (RFP) to complete work during the next year of the project. Forty-two proposals were received in response to the RFP. (2) Selected and convened a panel of experts to review the proposals and make funding recommendations. (3) Assigned each proposal to two or more reviewers and sent copies of all proposals to each review panelist. (4) Interfaced with Oak Ridge National Laboratory regarding QA/QC issues related to sampling and analysis for the project. (5) Held numerous phone conversations with DOE representatives regarding funding allocations procedure changes as a result of the delays in the Federal budget and appropriations process this year. This quarterly report briefly describes research projects ongoing in this program.

  8. Light out-coupling from LEDs by means of metal nanoparticles; Lichtauskopplung aus LEDs mittels Metallnanoteilchen

    Energy Technology Data Exchange (ETDEWEB)

    Goehler, Tino

    2010-12-17

    The external quantum efficiency of light-emitting diodes (LEDs) based on Al- GaAs/InGaAlP is limited by total internal reflection because of the high refractive index (typically between 3 and 4) of the semiconductor. Metal nanoparticles (MNP) deposited on the surface of the LED can be used as dipole scatterers in order to enhance the emission of the LED. In this thesis, first, single gold nanoparticles of various sizes deposited on such an LED were investigated. A clear enhancement is detected as long as the dipole plasmon resonance of the particle is at a shorter wavelength than the LED emission. If the plasmon resonance coincides with the LED emission or is at a larger wavelength, the enhancement turns into suppression. Numerical simulations indicate that this latter effect is mainly caused by the particle quadrupole resonance producing extra absorption. Arrays of MNPs can be produced by a special mask technique called ''Fischer pattern nanolithography'' and manipulated in shape and size by additional steps. Originally, the MNPs produced by this technique are triangular in shape and turn out to suppress the LED emission. After transformation of the particles to spheres, a clear enhancement was detected. Light that would otherwise remain trapped inside the substrate is coupled out by resonant plasmonic scattering. Investigations on analogous structures on a transparent high-index material (GaP) indicate a stronger coupling between the particles than expected on the basis of literature data. (orig.)

  9. Online and offline peer led models against bullying and cyberbullying.

    Science.gov (United States)

    Palladino, Benedetta Emanuela; Nocentini, Annalaura; Menesini, Ersilia

    2012-11-01

    The aim of the present study is to describe and evaluate an ongoing peer-led model against bullying and cyberbullying carried out with Italian adolescents. The evaluation of the project was made through an experimental design consisting of a pre-test and a post-test. Participants in the study were 375 adolescents (20.3% males), enrolled in 9th to 13th grades. The experimental group involved 231 students with 42 peer educators, and the control group involved 144 students. Results showed a significant decrease in the experimental group as compared to the control group for all the variables except for cyberbullying. Besides, in the experimental group we found a significant increase in adaptive coping strategies like problem solving and a significant decrease in maladaptive coping strategies like avoidance: these changes mediate the changes in the behavioural variables. In particular, the decrease in avoidance predicts the decrease in victimization and cybervictimization for peer educators and for the other students in the experimental classes whereas the increase in problem solving predicts the decrease in cyberbullying only in the peer educators group. Results are discussed following recent reviews on evidence based efficacy of peer led models.

  10. Buurtzorg: nurse-led community care.

    Science.gov (United States)

    Monsen, Karen A; de Blok, Jos

    2013-01-01

    Buurtzorg is a nurse-led, nurse-run organization of self-managed teams that provide home care to patients in their neighborhoods. Championing humanity over bureaucracy, autonomous teams work with primary care providers, community supports, and family resources to bring patients to optimal functioning as quickly as possible. The award-winning organization grew out of a common sense approach based on principles of trust, autonomy, creativity, simplicity, and collaboration. These organizational principles translate into highly effective and efficient care, satisfied patients, and enthusiastic nurses. The model is being replicated worldwide, with teams starting in Minnesota, Sweden, Japan, and other countries.

  11. Wheat Under LED's (Light Emitting Diodes)

    Science.gov (United States)

    2004-01-01

    Astroculture is a suite of technologies used to produce and maintain a closed controlled environment for plant growth. The two most recent missions supported growth of potato, dwarf wheat, and mustard plants, and provided scientists with the first opportunity to conduct true plant research in space. Light emitting diodes have particular usefulness for plant growth lighting because they emit a much smaller amount of radiant heat than do conventional lighting sources and because they have potential of directing a higher percentage of the emitted light onto plants surfaces. Furthermore, the high output LED's have emissions in the 600-700 nm waveband, which is of highest efficiency for photosynthesis by plants.

  12. Someone Has Led This Child To Believe

    OpenAIRE

    Louise, Regina

    2015-01-01

    ABSTRACTSOMEONE HAS LED THIS CHILD TO BELIEVE is a true story and continuation of the best-selling memoir Somebody’s Someone. After 12 year-old Regina Louise, tired of being beaten, battles and escapes an illegal guardian; she jumps from a two-story window and runs to a local police station where she is taken into custody, locked in a holding cell, and delivered to the Edgar Children’s Shelter, in Martinez California. Regina is closed off about her parents, her past…until she meets Jeanne Ke...

  13. Moral Issues in Intelligence-led Policing

    DEFF Research Database (Denmark)

    The core baseline of Intelligence-led Policing is the aim of increasing efficiency and quality of police work, with a focus on crime analysis and intelligence methods as tools for informed and objective decisions both when conducting targeted, specialized operations and when setting strategic...... priorities. This book critically addresses the proliferation of intelligence logics within policing from a wide array of scholarly perspectives. It considers questions such as: •How are precautionary logics becoming increasingly central in the dominant policing strategies? •What kind of challenges...... and the blurred and confrontational lines that can be observed between prevention, intelligence and investigation in police work....

  14. An investigation on LED customer’ behavior

    Directory of Open Access Journals (Sweden)

    Samaneh Sadat Khoramgah

    2013-03-01

    Full Text Available The recent advances in technology have created a challenge for customer on purchasing electronic devises since the cycle of media production such as TV, Mobile devices, etc. are getting short and people need to replace them by new products. The recent emerge of Light Emitting Diode (LED television has attracted many people and there is a concern to study the impact of important factors on customer behavior in this business. This paper presents an empirical study to study the effects of six variables including customer perception, motivation, cognitive learning, attitude, information and price on customer behavior for LED televisions produced by an Iranian firm in Tehran, Iran. The study designs a questionnaire consists of 27 questions and distributes it among some people who are potential customers of this product. We use multiple regression analysis to study the behavior of different factors on customer behavior. The results of our survey indicate that cognitive learning had the most influencing impact (0.22 on customer behavior followed by price (0.219, motivation (0.203, attitude (0.193, information (0.183 and perception (0.145.

  15. UV LED lighting for automated crystal centring.

    Science.gov (United States)

    Chavas, Leonard M G; Yamada, Yusuke; Hiraki, Masahiko; Igarashi, Noriyuki; Matsugaki, Naohiro; Wakatsuki, Soichi

    2011-01-01

    A direct outcome of the exponential growth of macromolecular crystallography is the continuously increasing demand for synchrotron beam time, both from academic and industrial users. As more and more projects entail screening a profusion of sample crystals, fully automated procedures at every level of the experiments are being implemented at all synchrotron facilities. One of the major obstacles to achieving such automation lies in the sample recognition and centring in the X-ray beam. The capacity of UV light to specifically react with aromatic residues present in proteins or with DNA base pairs is at the basis of UV-assisted crystal centring. Although very efficient, a well known side effect of illuminating biological samples with strong UV sources is the damage induced on the irradiated samples. In the present study the effectiveness of a softer UV light for crystal centring by taking advantage of low-power light-emitting diode (LED) sources has been investigated. The use of UV LEDs represents a low-cost solution for crystal centring with high specificity.

  16. Studying Light Color using White LED Lighting

    Science.gov (United States)

    Yamagishi, Misako; Yamaba, Kazuo; Nagata, Manori; Kubo, Chiho; Nokura, Kunihiro

    Recently, white Light Emitting Diodes (LEDs) are receiving attention worldwide as new lighting devices. This study examined effects of a lighting application on performance using white LEDs. The light color—the correlated color temperature (CCT) —was assessed. It affected to psychological states and physiological conditions. Three CCT conditions were respectively set for the experiment: 2500 K, 5000 K, and 8200 K. In all, 20 younger subjects (20-30 years old), 15 middle-aged to elderly subjects (45-60 years old) and 12 elderly subjects (over 65 years-old) participated. They were presented a Numerical Verification (NV) task for performance measurement. The psychological states on performance were evaluated using the lighting assessment questionnaire. The physiological conditions were recorded using an electrocardiograph. Results show that the effects of CCT differ among age groups. Especially, the performance of younger subjects might differ from CCT conditions; elderly subjects are affected by CCT condition because of their visual acuity or response to contrast of objects.

  17. Ear Problems

    Science.gov (United States)

    ... Infants and Children Chest Pain, Acute Chest Pain, Chronic Cold and Flu Cough Diarrhea Ear Problems Elimination Problems Elimination Problems in Infants and Children Eye Problems Facial Swelling Feeding Problems in Infants ...

  18. Urination Problems

    Science.gov (United States)

    ... Infants and Children Chest Pain, Acute Chest Pain, Chronic Cold and Flu Cough Diarrhea Ear Problems Elimination Problems Elimination Problems in Infants and Children Eye Problems Facial Swelling Feeding Problems in Infants ...

  19. Optimal local dimming for LED-backlit LCD displays via linear programming

    DEFF Research Database (Denmark)

    Shu, Xiao; Wu, Xiaolin; Forchhammer, Søren

    2012-01-01

    LED-backlit LCD displays hold the promise of improving the image quality while reducing the energy consumption with signal-dependent local dimming. To fully realize such potentials we propose a novel local dimming technique that jointly optimizes the intensities of LED backlights...... and the attenuations of LCD pixels. The objective is to minimize the distortion in luminance reproduction due to the leakage of LCD and the coarse granularity of the LED lights. The optimization problem is formulated as one of linear programming, and both exact and approximate algorithms are proposed. Simulation...... results demonstrate superior performances of the proposed algorithms over the existing local dimming algorithms....

  20. Dimming LEDs with Phase-Cut Dimmers. The Specifier's Process for Maximizing Success

    Energy Technology Data Exchange (ETDEWEB)

    Miller, N. J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Poplawski, M. E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2013-10-01

    DOE GATEWAY program report reviewing how phase-cut dimmers work, how LEDs differ from the incandescent lamps these dimmers were originally designed to control, and how those differences can lead to complications when attempting to dim LEDs. Providing both general guidance and step-by-step procedures for designing phase-controlled LED dimming on both new and existing projects—as well as real-world examples of how to use those procedures—the report aims to reduce the chance of experiencing compatibility-related problems and, if possible, ensure good dimming performance.

  1. LED--panacea or marketing hype?

    Science.gov (United States)

    Baillie, Jonathan

    2012-02-01

    With energy efficiency and carbon reduction, and the importance of a relaxing, therapeutic patient environment, ever more in the spotlight, LED lighting's proponents claim the technology offers healthcare estates personnel many of the answers on both fronts. However some observers believe its benefits are being over-sold, often to the detriment of other high-performing types of more 'conventional lighting', and to a sometimes uninitiated audience too easily swayed by slick sales patter. HEJ editor Jonathan Baillie spoke to one highly experienced lighting professional, Nicholas Bukorović, a former employee of Thorn, Cooper, and Thorlux Lighting, and the principal author of the last CIBSE/Society of Light and Lighting (SLL) Guide LG2 on healthcare lighting, to seek some expert illumination.

  2. Switched-capacitor isolated LED driver

    Science.gov (United States)

    Sanders, Seth R.; Kline, Mitchell

    2016-03-22

    A switched-capacitor voltage converter which is particularly well-suited for receiving a line voltage from which to drive current through a series of light emitting diodes (LEDs). Input voltage is rectified in a multi-level rectifier network having switched capacitors in an ascending-bank configuration for passing voltages in uniform steps between zero volts up to full received voltage V.sub.DC. A regulator section, operating on V.sub.DC, comprises switched-capacitor stages of H-bridge switching and flying capacitors. A current controlled oscillator drives the states of the switched-capacitor stages and changes its frequency to maintain a constant current to the load. Embodiments are described for isolating the load from the mains, utilizing an LC tank circuit or a multi-primary-winding transformer.

  3. Resident-Led Palliative Care Education Project.

    Science.gov (United States)

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

    2016-04-01

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

  4. Open LED Illuminator: A Simple and Inexpensive LED Illuminator for Fast Multicolor Particle Tracking in Neurons.

    Science.gov (United States)

    Bosse, Jens B; Tanneti, Nikhila S; Hogue, Ian B; Enquist, Lynn W

    2015-01-01

    Dual-color live cell fluorescence microscopy of fast intracellular trafficking processes, such as axonal transport, requires rapid switching of illumination channels. Typical broad-spectrum sources necessitate the use of mechanical filter switching, which introduces delays between acquisition of different fluorescence channels, impeding the interpretation and quantification of highly dynamic processes. Light Emitting Diodes (LEDs), however, allow modulation of excitation light in microseconds. Here we provide a step-by-step protocol to enable any scientist to build a research-grade LED illuminator for live cell microscopy, even without prior experience with electronics or optics. We quantify and compare components, discuss our design considerations, and demonstrate the performance of our LED illuminator by imaging axonal transport of herpes virus particles with high temporal resolution.

  5. Open LED Illuminator: A Simple and Inexpensive LED Illuminator for Fast Multicolor Particle Tracking in Neurons

    Science.gov (United States)

    Bosse, Jens B.; Tanneti, Nikhila S.; Hogue, Ian B.; Enquist, Lynn W.

    2015-01-01

    Dual-color live cell fluorescence microscopy of fast intracellular trafficking processes, such as axonal transport, requires rapid switching of illumination channels. Typical broad-spectrum sources necessitate the use of mechanical filter switching, which introduces delays between acquisition of different fluorescence channels, impeding the interpretation and quantification of highly dynamic processes. Light Emitting Diodes (LEDs), however, allow modulation of excitation light in microseconds. Here we provide a step-by-step protocol to enable any scientist to build a research-grade LED illuminator for live cell microscopy, even without prior experience with electronics or optics. We quantify and compare components, discuss our design considerations, and demonstrate the performance of our LED illuminator by imaging axonal transport of herpes virus particles with high temporal resolution. PMID:26600461

  6. Open LED Illuminator: A Simple and Inexpensive LED Illuminator for Fast Multicolor Particle Tracking in Neurons.

    Directory of Open Access Journals (Sweden)

    Jens B Bosse

    Full Text Available Dual-color live cell fluorescence microscopy of fast intracellular trafficking processes, such as axonal transport, requires rapid switching of illumination channels. Typical broad-spectrum sources necessitate the use of mechanical filter switching, which introduces delays between acquisition of different fluorescence channels, impeding the interpretation and quantification of highly dynamic processes. Light Emitting Diodes (LEDs, however, allow modulation of excitation light in microseconds. Here we provide a step-by-step protocol to enable any scientist to build a research-grade LED illuminator for live cell microscopy, even without prior experience with electronics or optics. We quantify and compare components, discuss our design considerations, and demonstrate the performance of our LED illuminator by imaging axonal transport of herpes virus particles with high temporal resolution.

  7. Tulane/Xavier Vaccine Peptide Program

    Science.gov (United States)

    2014-09-01

    with 4 mg Flufirvitide was sprayed through a Buchi Laboratory Spray dryer B290. The formulations were analyzed for Flufirvitide content, degradation...as a nasal spray . During the second stage of the project (above), twenty-five different formulations were prepared using a laboratory spray dryer ...These lyophilized formulations were later reconstituted with deionized water to use as a nasal spray . 10 In the second funding cycle, we 1

  8. Portable LED-induced autofluorescence spectroscopy for oral cancer diagnosis

    Science.gov (United States)

    Yan, Yung-Jhe; Huang, Ting-Wei; Cheng, Nai-Lun; Hsieh, Yao-Fang; Tsai, Ming-Hsui; Chiou, Jin-Chern; Duann, Jeng-Ren; Lin, Yung-Jiun; Yang, Chin-Siang; Ou-Yang, Mang

    2017-04-01

    Oral cancer is a serious and growing problem in many developing and developed countries. To improve the cancer screening procedure, we developed a portable light-emitting-diode (LED)-induced autofluorescence (LIAF) imager that contains two wavelength LED excitation light sources and multiple filters to capture ex vivo oral tissue autofluorescence images. Compared with conventional means of oral cancer diagnosis, the LIAF imager is a handier, faster, and more highly reliable solution. The compact design with a tiny probe allows clinicians to easily observe autofluorescence images of hidden areas located in concave deep oral cavities. The ex vivo trials conducted in Taiwan present the design and prototype of the portable LIAF imager used for analyzing 31 patients with 221 measurement points. Using the normalized factor of normal tissues under the excitation source with 365 nm of the central wavelength and without the bandpass filter, the results revealed that the sensitivity was larger than 84%, the specificity was not smaller than over 76%, the accuracy was about 80%, and the area under curve of the receiver operating characteristic (ROC) was achieved at about 87%, respectively. The fact shows the LIAF spectroscopy has the possibilities of ex vivo diagnosis and noninvasive examinations for oral cancer.

  9. Savings in Cooling Energy with a Thermal Management System for LED Lighting in Office Buildings

    Directory of Open Access Journals (Sweden)

    Byung-Lip Ahn

    2015-06-01

    Full Text Available Light-emitting diode (LED lighting should be considered for lighting efficiency enhancement, however, waste heat from light-emitting diode (LED lighting increases the internal cooling load during the summer season. In order to solve this problem we propose a thermal management system for light-emitting diode (LED lighting with a heat exchanger module integrated with the building’s heating, ventilation, and air conditioning (HVAC system to move the lighting’s waste heat outdoors. An experiment was carried out to investigate the thermal effects in a test chamber and the heat exchange rate between the heat sink and the duct air. The heat generated by the light-emitting diode (LED lighting was calculated as 78.1% of light-emitting diode (LED input power and the heat exchange rate of the lighting heat exchange module was estimated to be between 86.5% and 98.1% according to the light-emitting diode (LED input power and the flow rate of air passing the heat sink. As a result, the average light-emitting diode (LED lighting heat contribution rate for internal heat gain was determined as 0.05; this value was used to calculate the heating and cooling energy demand of the office building through an energy simulation program. In the simulation results, the cooling energy demand was reduced by 19.2% compared with the case of conventionally installed light-emitting diode (LED lighting.

  10. Atomic policies: history, problems

    International Nuclear Information System (INIS)

    Galvan, Cesare Giuseppe.

    1993-01-01

    Two kinds of problems follow from the development of nuclear technology: its use in (diversion to) armaments, and its dangers for the population. Both arise as social phenomena: technology can be diverted to military aims; and installations require specific measures in order not to expose human life to danger. The diffusion of this technology required a series of tentative solutions for such problems. Its history constitutes our first part. The second part aims at understanding the dynamics, which led to the diffusion of such a technology in the capitalist world. The concept of subsumption (especially of its realization) is suited to interpret the meanings of the social interests, which led content ro this diffusion. Subsumption is found between labor and capital, but also between society and state. At both levels, it shows that there was some social meaning in the diffusion of nuclear technology notwithstanding its problems. 590 refs

  11. LED Virtual Simulation based on Web3D

    OpenAIRE

    Lilan Liu; Liu Han; Zhiqi Lin; Manping Li; Tao Yu

    2014-01-01

    Regarding to the high price and low market popularity of current LED indoor lighting products, a LED indoor lighting platform is proposed based on Web3D technology. The internet virtual reality technology is integrated and applied into the LED collaborative e-commerce website with Virtools. According to the characteristics of the LED indoor lighting products, this paper introduced the method to build encapsulated model and three characteristics of LED lighting: geometrical, optical and behavi...

  12. Problems in problem analysis

    DEFF Research Database (Denmark)

    Almegaard, Henrik

    2014-01-01

    The majority of literature on engineering design methods is focused on the processes of fulfilling the design goals as efficiently as possible. This paper will focus on - and discuss - the processes of determining the design goals: the specifications. The purpose is to draw attention to the inher...... to the inherent problems, dilemmas and possibilities in these processes bearing in mind that that the most important decisions in a design project are taken in the beginning of the project....

  13. Experiencing LED: Lighting: New Form and Experiential Qualities Emerging in Lighting Systems using LED

    DEFF Research Database (Denmark)

    Petersen, Kjell Yngve; Kristensen, Ole; Søndergaard, Karin

    2012-01-01

    The project investigates what new forms and qualities of light emerge from technologies such as LED, with a particular focus on basic form qualities and parameters. Existing linear functional understandings of the relation between light source, light flow, reflection and visibility is challenged ...... by relational understandings, where the materiality and visibility of the light emerge through mutual influences between several adaptive and transformative elements....

  14. LED street lighting evaluation -- phase II : LED specification and life-cycle cost analysis.

    Science.gov (United States)

    2015-01-01

    Phase II of this study focused on developing a draft specification for LED luminaires to be used by IDOT : and a life-cycle cost analysis (LCCA) tool for solid state lighting technologies. The team also researched the : latest developments related to...

  15. Baby-led Weaning: A Preliminary Investigation.

    Science.gov (United States)

    D'Andrea, Elisa; Jenkins, Kielyn; Mathews, Maria; Roebothan, Barbara

    2016-06-01

    To date, baby-led weaning (BLW) has not been examined in a Canadian population. This research investigated common BLW practices and compared associated knowledge and perceptions of practicing mothers and health care professionals (HCPs). Sixty-five mothers practicing BLW and 33 HCPs were surveyed using 2 online questionnaires. Mothers were recruited through the Newfoundland and Labrador BLW Facebook page and HCPs via email at 2 regional health authorities. Mothers described BLW in terms of food shape and consistency (whole, solid); however, in practice, some mothers offered puréed foods such as infant cereals. More HCPs than mothers indicated choking, inadequate energy, and iron intake as concerns. Mothers relied on the Facebook page over HCPs for BLW information and support. Although all practicing mothers would recommend BLW to others, less than half (48.5%) of HCPs would support it in their practice. Mothers following BLW vary greatly in their experiences and adherence to BLW. They view the practice and its disadvantages very differently than HCPs. Although most HCPs were aware of BLW, few were familiar with specific practices. HCPs may benefit from a greater understanding of BLW to provide guidance to the growing number of mothers following this practice.

  16. Led Astray by Hemoglobin A1c

    Directory of Open Access Journals (Sweden)

    Jean Chen MD

    2016-01-01

    Full Text Available Hemoglobin A1c (A1c is used frequently to diagnose and treat diabetes mellitus. Therefore, it is important be aware of factors that may interfere with the accuracy of A1c measurements. This is a case of a rare hemoglobin variant that falsely elevated a nondiabetic patient’s A1c level and led to a misdiagnosis of diabetes. A 67-year-old male presented to endocrine clinic for further management after he was diagnosed with diabetes based on an elevated A1c of 10.7%, which is approximately equivalent to an average blood glucose of 260 mg/dL. Multiple repeat A1c levels remained >10%, but his home fasting and random glucose monitoring ranged from 92 to 130 mg/dL. Hemoglobin electrophoresis and subsequent genetic analysis diagnosed the patient with hemoglobin Wayne, a rare hemoglobin variant. This variant falsely elevates A1c levels when A1c is measured using cation-exchange high-performance liquid chromatography. When the boronate affinity method was applied instead, the patient’s A1c level was actually 4.7%. Though hemoglobin Wayne is clinically silent, this patient was erroneously diagnosed with diabetes and started on an antiglycemic medication. Due to this misdiagnosis, the patient was at risk of escalation in his “diabetes management” and hypoglycemia. Therefore, it is important that providers are aware of factors that may result in hemoglobin A1c inaccuracy including hemoglobin variants.

  17. Assessing the colour quality of LED sources

    DEFF Research Database (Denmark)

    Jost-Boissard, S.; Avouac, P.; Fontoynont, Marc

    2015-01-01

    The CIE General Colour Rendering Index is currently the criterion used to describe and measure the colour-rendering properties of light sources. But over the past years, there has been increasing evidence of its limitations particularly its ability to predict the perceived colour quality of light...... but also with a preference index or a memory index calculated without blue and purple hues. A very low correlation was found between appreciation and naturalness indicating that colour quality needs more than one metric to describe subjective aspects.......The CIE General Colour Rendering Index is currently the criterion used to describe and measure the colour-rendering properties of light sources. But over the past years, there has been increasing evidence of its limitations particularly its ability to predict the perceived colour quality of light...... sources and especially some LEDs. In this paper, several aspects of perceived colour quality are investigated using a side-by-side paired comparison method, and the following criteria: naturalness of fruits and vegetables, colourfulness of the Macbeth Color Checker chart, visual appreciation...

  18. Blue LED irradiation to hydration of skin

    Science.gov (United States)

    Menezes, Priscila F. C.; Requena, Michelle B.; Lizarelli, Rosane F., Z.; Bagnato, Vanderlei S.

    2015-06-01

    Blue LED system irradiation shows many important properties on skin as: bacterial decontamination, degradation of endogenous skin chromophores and biostimulation. In this clinical study we prove that the blue light improves the skin hydration. In the literature none authors reports this biological property on skin. Then this study aims to discuss the role of blue light in the skin hydration. Twenty patients were selected to this study with age between 25-35 years old and phototype I, II and III. A defined area from forearm was pre determined (A = 4.0 cm2). The study was randomized in two treatment groups using one blue light device (power of 5.3mW and irradiance of 10.8mW/cm2). The first treatment group was irradiated with 3J/cm2 (277seconds) and the second with 6J/cm2 (555 seconds). The skin hydration evaluations were done using a corneometer. The measurements were collected in 7, 14, 21 and 30 days, during the treatment. Statistical test of ANOVA, Tukey and T-Student were applied considering 5% of significance. In conclusion, both doses were able to improve the skin hydration; however, 6J/cm2 has kept this hydration for 30 days.

  19. Balance Problems

    Science.gov (United States)

    ... often, it could be a sign of a balance problem. Balance problems can make you feel unsteady. You may ... related injuries, such as a hip fracture. Some balance problems are due to problems in the inner ...

  20. Project-Based Learning with an Online Peer Assessment System in a Photonics Instruction for Enhancing LED Design Skills

    Science.gov (United States)

    Chang, Shu-Hsuan; Wu, Tsung-Chih; Kuo, Yen-Kuang; You, Li-Chih

    2012-01-01

    This study proposed a novel instructional approach, a two-stage LED simulation of Project-based learning (PBL) course with online peer assessment (OPA), and explored how to apply OPA to the different structured problems in a PBL course to enhance students' professional skills in LED design as well as meta-cognitive thinking. The participants of…

  1. [Population problem, comprehension problem].

    Science.gov (United States)

    Tallon, F

    1993-08-01

    Overpopulation of developing countries in general, and Rwanda in particular, is not just their problem but a problem for developed countries as well. Rapid population growth is a key factor in the increase of poverty in sub-Saharan Africa. Population growth outstrips food production. Africa receives more and more foreign food, economic, and family planning aid each year. The Government of Rwanda encourages reduced population growth. Some people criticize it, but this criticism results in mortality and suffering. One must combat this ignorance, but attitudes change slowly. Some of these same people find the government's acceptance of family planning an invasion of their privacy. Others complain that rich countries do not have campaigns to reduce births, so why should Rwanda do so? The rate of schooling does not increase in Africa, even though the number of children in school increases, because of rapid population growth. Education is key to improvements in Africa's socioeconomic growth. Thus, Africa, is underpopulated in terms of potentiality but overpopulated in terms of reality, current conditions, and possibilities of overexploitation. Africa needs to invest in human resources. Families need to save, and to so, they must refrain from having many children. Africa should resist the temptation to waste, as rich countries do, and denounce it. Africa needs to become more independent of these countries, but structural adjustment plans, growing debt, and rapid population growth limit national independence. Food aid is a means for developed countries to dominate developing countries. Modernization through foreign aid has had some positive effects on developing countries (e.g., improved hygiene, mortality reduction), but these also sparked rapid population growth. Rwandan society is no longer traditional, but it is also not yet modern. A change in mentality to fewer births, better quality of life for living infants, better education, and less burden for women must occur

  2. The High-efficiency LED Driver for Visible Light Communication Applications.

    Science.gov (United States)

    Gong, Cihun-Siyong Alex; Lee, Yu-Chen; Lai, Jyun-Liang; Yu, Chueh-Hao; Huang, Li Ren; Yang, Chia-Yen

    2016-08-08

    This paper presents a LED driver for VLC. The main purpose is to solve the low data rate problem used to be in switching type LED driver. The GaN power device is proposed to replace the traditional silicon power device of switching LED driver for the purpose of increasing switching frequency of converter, thereby increasing the bandwidth of data transmission. To achieve high efficiency, the diode-connected GaN power transistor is utilized to replace the traditional ultrafast recovery diode used to be in switching type LED driver. This work has been experimentally evaluated on 350-mA output current. The results demonstrate that it supports the data of PWM dimming level encoded in the PPM scheme for VLC application. The experimental results also show that system's efficiency of 80.8% can be achieved at 1-Mb/s data rate.

  3. The High-efficiency LED Driver for Visible Light Communication Applications

    Science.gov (United States)

    Gong, Cihun-Siyong Alex; Lee, Yu-Chen; Lai, Jyun-Liang; Yu, Chueh-Hao; Huang, Li Ren; Yang, Chia-Yen

    2016-08-01

    This paper presents a LED driver for VLC. The main purpose is to solve the low data rate problem used to be in switching type LED driver. The GaN power device is proposed to replace the traditional silicon power device of switching LED driver for the purpose of increasing switching frequency of converter, thereby increasing the bandwidth of data transmission. To achieve high efficiency, the diode-connected GaN power transistor is utilized to replace the traditional ultrafast recovery diode used to be in switching type LED driver. This work has been experimentally evaluated on 350-mA output current. The results demonstrate that it supports the data of PWM dimming level encoded in the PPM scheme for VLC application. The experimental results also show that system’s efficiency of 80.8% can be achieved at 1-Mb/s data rate.

  4. Automated system for the determination of patterns of high-intensity LEDs

    International Nuclear Information System (INIS)

    Baly, L.; Bolaño, L.; Arteche, R.; Broco, Y.; Quesada, I.; Rodríguez, E.

    2008-01-01

    Determination of high-intensity LEDs lighting patterns is an important step for the simulation and planning of arrays of these devices configurations. Currently there are systems based on CCD cameras able to efficiently solve this problem, however the high cost of these is a limiting factor for use. Another limitation of CCD cameras, is that they are designed for light levels much lower than those produced by a high-intensity LED. In this paper we present an automated system for the determination of the intensity of LEDs based on the scan point to point patterns. The results of the analysis of a type of LED based on arrays of bars with built-in optical system is presented.

  5. New reversing freeform lens design method for LED uniform illumination with extended source and near field

    Science.gov (United States)

    Zhao, Zhili; Zhang, Honghai; Zheng, Huai; Liu, Sheng

    2018-03-01

    In light-emitting diode (LED) array illumination (e.g. LED backlighting), obtainment of high uniformity in the harsh condition of the large distance height ratio (DHR), extended source and near field is a key as well as challenging issue. In this study, we present a new reversing freeform lens design algorithm based on the illuminance distribution function (IDF) instead of the traditional light intensity distribution, which allows uniform LED illumination in the above mentioned harsh conditions. IDF of freeform lens can be obtained by the proposed mathematical method, considering the effects of large DHR, extended source and near field target at the same time. In order to prove the claims, a slim direct-lit LED backlighting with DHR equal to 4 is designed. In comparison with the traditional lenses, illuminance uniformity of LED backlighting with the new lens increases significantly from 0.45 to 0.84, and CV(RMSE) decreases dramatically from 0.24 to 0.03 in the harsh condition. Meanwhile, luminance uniformity of LED backlighting with the new lens is obtained as high as 0.92 at the condition of extended source and near field. This new method provides a practical and effective way to solve the problem of large DHR, extended source and near field for LED array illumination.

  6. Peer-led prenatal breast-feeding education: a viable alternative to nurse-led education.

    Science.gov (United States)

    Rempel, Lynn A; Moore, Katrina C J

    2012-02-01

    To evaluate a prenatal breast-feeding class developed and facilitated by peer Breast-feeding Buddies. Non-equivalent control group quasi-experimental study comparing participants of the peer-led class (PLC) to those attending an established hospital-based breast-feeding nurse-led class (NLC). A brief questionnaire was completed immediately prior to the class, and telephone interviews were conducted approximately one week following the class, and one and six months post partum. 54 expectant mothers who registered for the community PLC and 55 expectant mothers who registered for the NLC. Breast-feeding intentions were measured at all time-points. Class evaluations, breast-feeding experiences, and breast-feeding support were measured at all post-class interviews. Both classes were considered worthwhile, but the PLC class was rated as more helpful and participants appreciated learning from the peers' personal experiences. Mothers taught by peers were more likely to access peer breast-feeding support. PLC participants initially decreased their prenatal breast-feeding duration intentions but had significantly stronger intentions to continue breast feeding at six months than did NLC mothers. A peer-led prenatal breast-feeding class is as effective as a traditional model of breast-feeding education and is a valuable tool to promote and support successful breast feeding. RECOMMENDATIONS FOR PRACTICE: Peer-led breast-feeding classes should be provided to enhance the accessibility of breast-feeding education and support for expectant mothers. Copyright © 2010 Elsevier Ltd. All rights reserved.

  7. Is Nigerian Growth Trade-Led?

    Directory of Open Access Journals (Sweden)

    Ismail Adigun Olayemi

    2017-09-01

    Full Text Available Purpose: Nigeria is currently in recession, a situation described as induced by decreases in oil output and export, caused by the bombings of oil pipelines in its Niger Delta region, and the unanticipated decline in its value of exports and currency, resulting from the decline in oil prices. With the export value decline, somersaulting to growth, could it then be that Nigerian economic growth is trade constrained? How important is export to growth?. This study investigates these, its invention balances in its methodology. Design/methodology/approach: To achieve the above, this paper employs the Autoregressive Distributed Lag Model (ARDL and the Thirlwall's Law of balance of payment led growth, using a combination of annual (1981–2016 and quarterly (2000Q1–2016Q4 data to ensure robustness. This combination not only allows for comparison but also ensures the reflection of the current government's trade decisions and trade activities; these are missing in other studies. Findings: Using the Wald F-Statistic, Economic growth is found to be equal to export growth rate divided by income elasticity of import, the estimated income elasticity of import which is greater than 100% or elastic reflects over dependence on import both in the short and long run, implying that Nigeria imports more than it earns. Exchange rate and terms of trade are insignificant especially in the long run. The study calls for monitoring of import contents; the government needs to enforce its recent directives to stop importation of some products that are already being produced within with higher quality and adequate export promotion strategies should be formulated and enforced. Research limitations/implications: The data span is restricted by data availability, the study could as well confirm its results with monthly data for robustness and better confidence, but most of the variables are reported annually and quarterly only. Originality/value: Many studies have confirmed the

  8. Modelling intelligence-led policing to identify its potential

    NARCIS (Netherlands)

    Hengst-Bruggeling, M. den; Graaf, H.A.L.M. de; Scheepstal, P.G.M. van

    2014-01-01

    lntelligence-led policing is a concept of policing that has been applied throughout the world. Despite some encouraging reports, the effect of intelligence-led policing is largely unknown. This paper presents a method with which it is possible to identify intelligence-led policing's potential to

  9. Design methodologies for reliability of SSL LED boards

    NARCIS (Netherlands)

    Jakovenko, J.; Formánek, J.; Perpiñà, X.; Jorda, X.; Vellvehi, M.; Werkhoven, R.J.; Husák, M.; Kunen, J.M.G.; Bancken, P.; Bolt, P.J.; Gasse, A.

    2013-01-01

    This work presents a comparison of various LED board technologies from thermal, mechanical and reliability point of view provided by an accurate 3-D modelling. LED boards are proposed as a possible technology replacement of FR4 LED boards used in 400 lumen retrofit SSL lamps. Presented design

  10. CALiPER Snapshot Report: Indoor LED Luminaires

    Energy Technology Data Exchange (ETDEWEB)

    None

    2014-04-01

    Snapshot reports use data from DOE's LED Lighting Facts product list to compare the LED performance to standard technologies, and are designed to help lighting retailers, distributors, designers, utilities, energy efficiency program sponsors, and other stakeholders understand the current state of the LED market and its trajectory.

  11. Luminaries-level structure improvement of LEDs for heat dissipation ...

    Indian Academy of Sciences (India)

    Heat dissipation enhancement of LED luminaries is of great significance to the large-scale application of LED. Luminaries-level structure improvement by the method of boring through-hole is adopted to intensify heat dissipation. Furthermore, the natural convection heat transfer process of LED luminaries is simulated by ...

  12. EC-LEDS Supports the Low-Carbon Transition

    Energy Technology Data Exchange (ETDEWEB)

    2016-09-01

    EC-LEDS is a flagship U.S. government-led effort that assists countries to create and implement low emission development strategies, or LEDS -- development frameworks that promote sustainable social and economic development while reducing greenhouse gas emissions over the medium to long term.

  13. Thermal design for the high-power LED lamp

    International Nuclear Information System (INIS)

    Tian Xiaogai; Chen Wei; Zhang Jiyong

    2011-01-01

    This paper summarizes different kinds of heat sinks on the market for high power LED lamps. Analysis is made on the thermal model of LED, PCB and heat sink separately with a simplified mode provided. Two examples of simulation are illustrated as a demonstration for the thermal simulation as guidance for LED lamp design. (semiconductor devices)

  14. Mapping Student-Led Peer Learning in the UK

    Science.gov (United States)

    Keenan, Chris

    2014-01-01

    Peer-led academic learning has increased in importance, but there is little sense of how many institutions support it, how they understand its purposes or what peer-led learning best practice is. This report examines the provision of peer-led learning in the UK. It identifies challenges and opportunities, including international perspectives and…

  15. 'No blue' LED solution for photolithography room illumination

    DEFF Research Database (Denmark)

    Ou, Haiyan; Corell, Dennis Dan; Dam-Hansen, Carsten

    2010-01-01

    This paper explored the feasibility of using a LED-based bulb as the illumination light source for photolithography room. A no-blue LED was designed, and the prototype was fabricated. The spectral power distribution of both the LED bulb and the yellow fluorescent tube was measured. Based on that,...

  16. Speech Problems

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Speech Problems KidsHealth / For Teens / Speech Problems What's in ... a person's ability to speak clearly. Some Common Speech and Language Disorders Stuttering is a problem that ...

  17. Hemiequilibrium problems

    Directory of Open Access Journals (Sweden)

    Muhammad Aslam Noor

    2004-01-01

    Full Text Available We consider a new class of equilibrium problems, known as hemiequilibrium problems. Using the auxiliary principle technique, we suggest and analyze a class of iterative algorithms for solving hemiequilibrium problems, the convergence of which requires either pseudomonotonicity or partially relaxed strong monotonicity. As a special case, we obtain a new method for hemivariational inequalities. Since hemiequilibrium problems include hemivariational inequalities and equilibrium problems as special cases, the results proved in this paper still hold for these problems.

  18. LED lighting for greenhouses. Final report; LED belysning til vaeksthuse. Slutrapport

    Energy Technology Data Exchange (ETDEWEB)

    OEstergaard, J.E. (Syddansk Univ. (SDU). Erhvervsinnovation og Teknologi, Odense (Denmark))

    2011-01-15

    The project had 3 main objectives: 1) To develop a prototype of a LED-based luminaire that can replace the existing glasshouse horticultural lighting. The project have developed a working prototype and experimentally replaced the traditional HPS luminaires in a controlled growing area. The project succeeded in producing plants of comparable quality. However, the project shows that the prototype can be improved by: x) being further integrated into the existing horticultural production technology (eg climate computers and purchase of electricity) x) adapting configuration of luminaires specifically to each plant variety x) adapting different cooling technologies to match specific customer needs x) In some cases being combined with heat input to optimize the overall economy. 2) To achieve an effective electricity savings of 50-80% - equivalent to a value of approx. DKK 5 million for a medium sized nursery. The verified electricity savings was 40%. In test setups and in well defined and controllable production areas the prototypes achieved electricity savings of > 50%. It is expected that a new generation of LEDs (Q3 2010) will allow for greater power savings. 3) To continue prototype development and initiate commercialization of the project through the company Fionia Lighting A/S. The shareholders of the company have allocated capital to the company to allow us to address the main challenges in commercializing the technology. It is expected that the company will enter a strategic alliance with a major industrial player in the beginning of 2011. (Author)

  19. Novel Carbazole Skeleton-Based Photoinitiators for LED Polymerization and LED Projector 3D Printing

    Directory of Open Access Journals (Sweden)

    Assi Al Mousawi

    2017-12-01

    Full Text Available Radical chemistry is a very convenient way to produce polymer materials. Here, an application of a particular photoinduced radical chemistry is illustrated. Seven new carbazole derivatives Cd1–Cd7 are incorporated and proposed as high performance near-UV photoinitiators for both the free radical polymerization (FRP of (methacrylates and the cationic polymerization (CP of epoxides utilizing Light Emitting Diodes LEDs @405 nm. Excellent polymerization-initiating abilities are found and high final reactive function conversions are obtained. Interestingly, these new derivatives display much better near-UV polymerization-initiating abilities compared to a reference UV absorbing carbazole (CARET 9H-carbazole-9-ethanol demonstrating that the new substituents have good ability to red shift the absorption of the proposed photoinitiators. All the more strikingly, in combination with iodonium salt, Cd1–Cd7 are likewise preferred as cationic photoinitiators over the notable photoinitiator bis(2,4,6-trimethylbenzoylphenylphosphine oxide (BAPO for mild irradiation conditions featuring their remarkable reactivity. In particular their utilization in the preparation of new cationic resins for LED projector 3D printing is envisioned. A full picture of the included photochemical mechanisms is given.

  20. Visible light communication based vehicle positioning using LED street light and rolling shutter CMOS sensors

    Science.gov (United States)

    Do, Trong Hop; Yoo, Myungsik

    2018-01-01

    This paper proposes a vehicle positioning system using LED street lights and two rolling shutter CMOS sensor cameras. In this system, identification codes for the LED street lights are transmitted to camera-equipped vehicles through a visible light communication (VLC) channel. Given that the camera parameters are known, the positions of the vehicles are determined based on the geometric relationship between the coordinates of the LEDs in the images and their real world coordinates, which are obtained through the LED identification codes. The main contributions of the paper are twofold. First, the collinear arrangement of the LED street lights makes traditional camera-based positioning algorithms fail to determine the position of the vehicles. In this paper, an algorithm is proposed to fuse data received from the two cameras attached to the vehicles in order to solve the collinearity problem of the LEDs. Second, the rolling shutter mechanism of the CMOS sensors combined with the movement of the vehicles creates image artifacts that may severely degrade the positioning accuracy. This paper also proposes a method to compensate for the rolling shutter artifact, and a high positioning accuracy can be achieved even when the vehicle is moving at high speeds. The performance of the proposed positioning system corresponding to different system parameters is examined by conducting Matlab simulations. Small-scale experiments are also conducted to study the performance of the proposed algorithm in real applications.

  1. Effect of LED light stimulation on sleep latency in night shift people

    Science.gov (United States)

    Wu, Jih-Huah; Chang, Yang-Chyuan; Chiu, Hui-Ling; Fang, Wei; Shan, Yi-Chia; Chen, Ming-Jie; Chang, Yu-Ting

    2014-05-01

    Sleep problems are getting worse and worse in modern world. They have a severe impact on psychological and physical health, as well as social performances. From our previous study, the brainwave α rhythm, θ wave and β wave were affected by radiating the palm of the subjects with low-level laser array. In addition, from other study, the LED array stimulator (LEDAS) also has the similar effects. In the present study, LED light was used to radiate the left palm of the subjects too, and the effects were assessed with the multiple sleep latency test (MSLT) and heart-rate variability (HRV) analysis. The results revealed that it doesn't have significant meaning between these two groups. However, the tendency of the sleep latency (SL) in the LED group was shorter than that in the control group. In addition, the autonomic nervous system (ANS) analysis showed that the sympathetic nervous system was getting larger in the LED group than that in the control group, and total ANS activity were mainly getting larger in the LED group. We infer that this LED stimulation could reduce SL and balance ANS activity of the night-shift people. In the future, the further study will be conducted on normal subjects.

  2. Technology Analysis of Global Smart Light Emitting Diode (LED Development Using Patent Data

    Directory of Open Access Journals (Sweden)

    Sangsung Park

    2017-08-01

    Full Text Available Technological developments related to smart light emitting diode (LED systems have progressed rapidly in recent years. In this paper, patent documents related to smart LED technology are collected and analyzed to understand the technology development of smart LED systems. Most previous studies of the technology were dependent on the knowledge and experience of domain experts, using techniques such as Delphi surveys or technology road-mapping. These approaches may be subjective and lack robustness, because the results can vary according to the selected expert groups. We therefore propose a new technology analysis methodology based on statistical modeling to obtain objective and relatively stable results. The proposed method consists of visualization based on Bayesian networks and a linear count model to analyze patent documents related to smart LED technology. Combining these results, a global hierarchical technology structure is created that can enhance the sustainability in smart LED system technology. In order to show how this methodology could be applied to real-world problems, we carry out a case study on the technology analysis of smart LED systems.

  3. LED Based Optical Wireless Communication System for WBAN

    Directory of Open Access Journals (Sweden)

    ATTIYA BAQAI

    2016-10-01

    Full Text Available In this paper the O-WBANs (Optical Wireless Body Area Networks is presented as an alternative to the radio and microwave BANs which are plagued with issues like interference, power hungry, hazardous and costly spectrum. Various experiments performed in this work demonstrate the feasibility of LED (Light-Emitting Diode based optical systems to be used for BANs. The system cost is kept as low as possible. Mainly the effects on the optical link are observed under ambient light and with different modulation schemes by varying link distance and line of sight in this paper. Experimental results reveal the satisfactory link availability up to the distance of 7 feet (around 2m, the optimum range of WBAN and within the field of view of 30-60º. The low cost solution presented in this paper meets the WBANs data rate requirement for physiological data (i.e. 10-100 kbps. As IR (Infra-Red signals do not provide any interference with the signals generated by the medical equipment of hospitals which is the problem in case of RF or microwave signals, additionally the IR signals are confined within a room hence IR signaling can prove to be potential candidate for WBAN fulfilling its security and limited access requirement.

  4. Replacing lecture with peer-led workshops improves student learning.

    Science.gov (United States)

    Preszler, Ralph W

    2009-01-01

    Peer-facilitated workshops enhanced interactivity in our introductory biology course, which led to increased student engagement and learning. A majority of students preferred attending two lectures and a workshop each week over attending three weekly lectures. In the workshops, students worked in small cooperative groups as they solved challenging problems, evaluated case studies, and participated in activities designed to improve their general learning skills. Students in the workshop version of the course scored higher on exam questions recycled from preworkshop semesters. Grades were higher over three workshop semesters in comparison with the seven preworkshop semesters. Although males and females benefited from workshops, there was a larger improvement of grades and increased retention by female students; although underrepresented minority (URM) and non-URM students benefited from workshops, there was a larger improvement of grades by URM students. As well as improving student performance and retention, the addition of interactive workshops also improved the quality of student learning: Student scores on exam questions that required higher-level thinking increased from preworkshop to workshop semesters.

  5. Comparison between peer-led and teacher-led education in tuberculosis prevention in rural middle schools in Chongqing, China.

    Science.gov (United States)

    Liu, Qin; Liu, Liping; Vu, Huyen; Liu, Xiaoxue; Tang, Shenglan; Wang, Hong

    2015-03-01

    The aim of this study was to investigate the efficacy of tuberculosis (TB) education through a comparison of peer-led and teacher-led methods of education about TB prevention among middle school students in rural Chongqing, China. A preintervention and postintervention questionnaire survey was conducted in 2 different middle school student groups to measure changes in knowledge, attitude, and practice (KAP) status of those students before and after each TB education program. Of 1265 students participating in the preintervention survey, 1176 completed the postintervention survey. KAP scores of both peer-led and teacher-led groups after intervention improved by as much as 2 times compared with before the intervention and those of the control group (P led education group (P led group had a larger improvement than the peer-led group in practice scores (P < .01) in immediate effect evaluation. © 2013 APJPH.

  6. Development of high-performance solar LED lighting system

    KAUST Repository

    Huang, B.J.

    2010-08-01

    The present study developed a high-performance charge/discharge controller for stand-alone solar LED lighting system by incorporating an nMPPO system design, a PWM battery charge control, and a PWM battery discharge control to directly drive the LED. The MPPT controller can then be removed from the stand-alone solar system and the charged capacity of the battery increases 9.7%. For LED driven by PWM current directly from battery, a reliability test for the light decay of LED lamps was performed continuously for 13,200 h. It has shown that the light decay of PWM-driven LED is the same as that of constant-current driven LED. The switching energy loss of the MOSFET in the PWM battery discharge control is less than 1%. Three solar-powered LED lighting systems (18 W, 100 W and 150 W LED) were designed and built. The long-term outdoor field test results have shown that the system performance is satisfactory with the control system developed in the present study. The loss of load probability for the 18 W solar LED system is 14.1% in winter and zero in summer. For the 100 W solar LED system, the loss of load probability is 3.6% in spring. © 2009 Elsevier Ltd. All rights reserved.

  7. LED light engine concept with ultra-high scalable luminance

    Science.gov (United States)

    Hoelen, Christoph; de Boer, Dick; Bruls, Dominique; van der Eyden, Joost; Koole, Rolf; Li, Yun; Mirsadeghi, Mo; Vanbroekhoven, Vincent; Van den Bergh, John-John; Van de Voorde, Patrick

    2016-03-01

    Although LEDs have been introduced successfully in many general lighting applications during the past decade, high brightness light source applications are still suffering from the limited luminance of LEDs. High power LEDs are generally limited in luminance to ca 100 Mnit (108 lm/m2sr) or less, while dedicated devices for projection may achieve luminance values up to ca 300 Mnit with phosphor converted green. In particular for high luminous flux applications with limited étendue, like in front projection systems, only very modest luminous flux values in the beam can be achieved with LEDs compared to systems based on discharge lamps. In this paper we introduce a light engine concept based on a light converter rod pumped with blue LEDs that breaks through the étendue and brightness limits of LEDs, enabling LED light source luminance values that are more than 4 times higher than what can be achieved with LEDs so far. In LED front projection systems, green LEDs are the main limiting factor. With our green light emitting modules, peak luminance values well above 1.2 Gnit have been achieved, enabling doubling of the screen brightness of LED based DLP projection systems, and even more when this technology is applied to other colors as well. This light source concept, introduced as the ColorSpark High Lumen Density (HLD) LED technology, enables a breakthrough in the performance of LED-based light engines not only for projection, where >2700 ANSI lm was demonstrated, but for a wide variety of high brightness applications.

  8. Intelligent control of dynamic LED lighting; Intelligent styring af dynamisk LED belysning. Slutrapport

    Energy Technology Data Exchange (ETDEWEB)

    Thorseth, A.; Corell, D.; Hansen, Soeren S.; Dam-Hansen, C.; Petersen, Paul Michael

    2013-01-15

    The project has resulted in a prototype of a new intelligent lighting control system. The control system enables the end user to control his or her own local lighting environment (lighting zone) according to individual preferences and needs. The report provides a description of how the developed intelligent lighting system is composed and functions. The system is designed as a work lamp that enables dynamic change of the light color scheme according to a number of light control algorithms. It is specifically designed in relation to user tests of the intelligent lighting system, which is carried out in the final part of the project. An intelligent and advanced control of LED lighting was developed, which enables optimization of the user's light conditions in a given situation. Based on a number of known parameters, the system can control lighting so that at any time optimal light conditions are created, using a minimum of electric power. (LN)

  9. Problem gambling.

    Science.gov (United States)

    Thomas, Shane

    2014-06-01

    Problem gambling is an increasingly common problem in Australia. General practitioners (GPs) have an important role in ensuring that problem gambling is detected and treated. We review the clinical issues associated with the detection and treatment of problem gambling. At any one time 1% of the adult Australian population satisfy the clinical criteria for problem gambling; a further 4% are at a significant risk. Problem gambling frequently presents with other serious mental health conditions. There are several guidelines from the National Health and Medical Research Council and Australian Medical Association that recommend GP involvement in screening for problem gambling. Simple one-item tools are available for that purpose. GP screening and referral for problem gambling addresses the currently very low rates of treatment. Effective and durable psychological treatments are available for the treatment of problem gambling including cognitive behaviour therapy and motivational interviewing.

  10. Characteristics of white LED transmission through a smoke screen

    Science.gov (United States)

    Zheng, Yunfei; Yang, Aiying; Feng, Lihui; Guo, Peng

    2018-01-01

    The characteristics of white LED transmission through a smoke screen is critical for visible light communication through a smoke screen. Based on the Mie scattering theory, the Monte Carlo transmission model is established. Based on the probability density function, the white LED sampling model is established according to the measured spectrum of a white LED and the distribution angle of the lambert model. The sampling model of smoke screen particle diameter is also established according to its distribution. We simulate numerically the influence the smoke thickness, the smoke concentration and the angle of irradiance of white LED on transmittance of the white LED. We construct a white LED smoke transmission experiment system. The measured result on the light transmittance and the smoke concentration agreed with the simulated result, and demonstrated the validity of simulation model for visible light transmission channel through a smoke screen.

  11. Competing in the Global LED Industry: The Case of Taiwan

    Directory of Open Access Journals (Sweden)

    Yu-Shan Su

    2014-01-01

    Full Text Available Light-emitting diode (LED is a very essential application for energy-savings nowadays. The revenue of the Taiwan LED components industry is ranked top one in the world, followed by that of Japan and South Korea. Based on the advantage of their electronics industry, Taiwanese LED companies create a unique model to compete with the international firms. Large international LED companies achieve economies of scale by vertically integrating their operations. Taiwanese LED companies specialize and achieve an optimal efficiency by vertically disintegrating across the upstream, midstream, and downstream sectors in the value chains. Taiwanese LED companies create economies of scale and economies of scope through a complete industrial value chain.

  12. A novel amblyopia treatment system based on LED light source

    Science.gov (United States)

    Zhang, Xiaoqing; Chen, Qingshan; Wang, Xiaoling

    2011-05-01

    A novel LED (light emitting diode) light source of five different colors (white, red, green, blue and yellow) is adopted instead of conventional incandescent lamps for an amblyopia treatment system and seven training methods for rectifying amblyopia are incorporated so as for achieving an integrated therapy. The LED light source is designed to provide uniform illumination, adjustable light intensity and alterable colors. Experimental tests indicate that the LED light source operates steadily and fulfills the technical demand of amblyopia treatment.

  13. Development of Wireless Dimming Control System for LED Stage Light

    OpenAIRE

    Wang Hui Qin; Bai Shi Lei

    2016-01-01

    Compared with the existing wire dimming system of LED stage light which uses the heavy light operating console to adjust the brightness of stage light, a portable wireless dimming control system for LED stage lighting is proposed, fabricated and tested in this paper. The scheme with the core of ATmega16L microcontroller is composed of wireless transmission and reception units, constant current driving circuit of LED, and the control circuit between this two modules. Through the system present...

  14. Null bactericidal effect of ultraviolet radiation emitted by LEDs.

    OpenAIRE

    Francisco Alcántara Muñoz; Rafael Moreno-Rojas; Alicia Moreno Ortega; José Emilio Muñoz Cañete; Rafael Gómez Díaz

    2016-01-01

    This research has aimed to assess the bactericidal effect of ultraviolet light emitted by LEDS on the growth on Petri dishes of microorganisms whose legal limits in foods have been established. An electrically fed apparatus has been designed with precise timing and a camera to prevent light spillage, in which two ultraviolet radiation emission devices were connected by LED technology at different wavelengths: through an array of LEDS emitting at around 350nm, and a single specific...

  15. Interior LED Lighting Technology. Navy Energy Technology Validation (Techval) Program

    Science.gov (United States)

    2015-09-01

    evaluated using the Illumination Engineering Societies’ (IES) TM-21 manual. The TM- 21 manual provides a standardized method for evaluating when an LED...the equipment. The Cree luminaires installed in this study are rated for 75,000 hours of service, based on calculation methods that extrapolated...should be replaced with LED lamps. • Replace MR-16 lamps with LED lamps since this type of fixture is used to provide accent lighting and is

  16. Warm white LEDs lighting over Ra=95 and its applications

    Science.gov (United States)

    Kobashi, Katsuya; Taguchi, Tsunemasa

    2007-02-01

    We have for the first time developed warm white LEDs lighting using a combination of near ultraviolet LED and three-band (red, green and blue) white phosphors. This LED has the average color-rendering index Ra=96. Moreover, special color-rendering index R9 (red) and R15 (face color of Japanese) are estimated to be 95 and 97, respectively. We will describe the results of evaluation on the medical lighting applications such as operation, treatment and endoscope experiments, application to the LED fashions and application to the Japanese antique art (ink painting) lighting.

  17. A synthetic method of solar spectrum based on LED

    Science.gov (United States)

    Wang, Ji-qiang; Su, Shi; Zhang, Guo-yu; Zhang, Jian

    2017-10-01

    A synthetic method of solar spectrum which based on the spectral characteristics of the solar spectrum and LED, and the principle of arbitrary spectral synthesis was studied by using 14 kinds of LED with different central wavelengths.The LED and solar spectrum data were selected by Origin Software firstly, then calculated the total number of LED for each center band by the transformation relation between brightness and illumination and Least Squares Curve Fit in Matlab.Finally, the spectrum curve of AM1.5 standard solar spectrum was obtained. The results met the technical indexes of the solar spectrum matching with ±20% and the solar constant with >0.5.

  18. Excellent color rendering indexes of multi-package white LEDs.

    Science.gov (United States)

    Oh, Ji Hye; Yang, Su Ji; Sung, Yeon-Goog; Do, Y R

    2012-08-27

    This study introduces multi-package white light-emitting diodes (LEDs) system with the ability to realize high luminous efficacy and an excellent color rendering index (CRI, R a) using the R B,M A B,M G B,M C B (R B,M A B,M G B,M denoted as a long-pass dichroic filter (LPDF)-capped, monochromatic red, amber and green phosphor converted-LED (pc-LED) pumped by a blue LED chip, and C B denoted as a cyan and blue mixed pc-LED pumped by a blue LED) system. The luminous efficacy and color rendering index (CRI) of multi-package white LED systems are compared while changing the concentration of the cyan phosphor used in the paste of a cyan-blue LED package and the driving current of individual LEDs in multi-package white LEDs at correlated color temperatures (CCTs) ranging from 6,500 K (cold white) to 2,700 K (warm white) using a set of eight CCTs as specified by the American National Standards Institute (ANSI) standard number C78.377-2008. A R B,M A B,M G B,M C B white LED system provides high luminous efficacy (≥ 96 lm/W) and a color rendering index (≥ 91) encompassing the complete CCT range. We also compare the optical properties of the R B,M A B,M G B,M C B system with those of the R B,M A B,M G B,M B and RAGB (red, amber, green, and blue semiconductor-type narrow-spectrum-band LEDs) systems. It can be expected that the cyan color added to a blue LED in multi-package white LEDs based on LPDF-capped, phosphor-converted monochromatic LEDs will meet the needs of the high-quality, highly efficient, full-color white LED lighting market in the near future.

  19. UV-LED Curing Efficiency of Wood Coatings

    OpenAIRE

    Landry, Véronic; Blanchet, Pierre; Boivin, Gabrielle; Bouffard, Jean-François; Vlad, Mirela

    2015-01-01

    Ultraviolet light emitting diodes (UV-LEDs) have attracted great interest in recent years. They can be used to polymerize coatings, such as those used for prefinished wood flooring. In this project, two lamps were compared for their suitability to be used on a wood flooring finishing line: a UV-microwave and a UV-LED lamp. Low heat emission was found for the UV-LED lamp compared to the UV-microwave one. This study also reveals that the 4 W/cm2 UV-LED lamp used is not powerful enough to cure ...

  20. High-Modulation-Speed LEDs Based on III-Nitride

    Science.gov (United States)

    Chen, Hong

    III-nitride InGaN light-emitting diodes (LEDs) enable wide range of applications in solid-state lighting, full-color displays, and high-speed visible-light communication. Conventional InGaN quantum well LEDs grown on polar c-plane substrate suffer from quantum confined Stark effect due to the large internal polarization-related fields, leading to a reduced radiative recombination rate and device efficiency, which limits the performance of InGaN LEDs in high-speed communication applications. To circumvent these negative effects, non-trivial-cavity designs such as flip-chip LEDs, metallic grating coated LEDs are proposed. This oral defense will show the works on the high-modulation-speed LEDs from basic ideas to applications. Fundamental principles such as rate equations for LEDs/laser diodes (LDs), plasmonic effects, Purcell effects will be briefly introduced. For applications, the modal properties of flip-chip LEDs are solved by implementing finite difference method in order to study the modulation response. The emission properties of highly polarized InGaN LEDs coated by metallic gratings are also investigated by finite difference time domain method.

  1. Precoder design for indoor visible light communications with multiple RGB LEDs

    Science.gov (United States)

    Gao, Qian; Lang, Tian; Bo, Feng; Chen, Gang; Hua, Yingbo

    2013-09-01

    In this paper, we consider the problem of precoder design for an optical intensity modulation (IM) system with multiple redgreen- blue (RGB) light emitting diodes (LEDs) as transmitters and imaging lens with color filters as receivers. The purpose of using a precoder is to optimally allocate power for each LED based on the current channel condition to minimize the detection error rate. To achieve the goal, an non-convex optimization problem due to a nonconvex constraint is formulated first taking into account several crucial lighting constraints, such as flicker-free, color rendering index (CRI), and luminous efficacy rate (LER) as well as the average optical intensity constraint and non-negative transmitter-side signal constraint. By manipulations we transform the problem into a semi-definite programming (SDP) and by approximation we relaxed the non-convex constraint into a convex one. The resulting convex problem is iteratively solved by CVX, an add-in to MATLAB, which jointly optimizes the precoder and DC-biases driving each LED. We assume that M-PAM signal constellation is used as input to the precoder and an MMSE receiver is applied to recover the input signals in this paper, while our method is not restrict to the specific choice.

  2. Childbirth Problems

    Science.gov (United States)

    ... the mother, baby, or both. Possible complications include Preterm (premature) labor, when labor starts before 37 completed weeks of pregnancy Problems with the umbilical cord Problems with the position of the baby, such as breech, in which ...

  3. Ankle Problems

    Science.gov (United States)

    ... Read MoreDepression in Children and TeensRead MoreBMI Calculator Ankle ProblemsFollow this chart for more information about problems that can cause ankle pain. Our trusted Symptom Checker is written and ...

  4. Walking Problems

    Science.gov (United States)

    ... your legs or feet Movement disorders such as Parkinson's disease Diseases such as arthritis or multiple sclerosis Vision or balance problems Treatment of walking problems depends on the cause. Physical therapy, surgery, or mobility aids may help.

  5. Solving Environmental Problems

    DEFF Research Database (Denmark)

    Ørding Olsen, Anders; Sofka, Wolfgang; Grimpe, Christoph

    2017-01-01

    dispersed. Hence, firms need to collaborate. We shed new light on collaborative search strategies led by firms in general and for solving environmental problems in particular. Both topics are largely absent in the extant open innovation literature. Using data from the European Seventh Framework Program...... for Research and Technological Development (FP7), our results indicate that the problem-solving potential of a search strategy increases with the diversity of existing knowledge of the partners in a consortium and with the experience of the partners involved. Moreover, we identify a substantial negative effect......Recent innovation and strategy research emphasizes the importance of firm’s search for external knowledge to improve innovation performance. We focus on such search strategies within the domain of sustainable innovation in which problems are inherently complex and the relevant knowledge is widely...

  6. Approaches to Sex Education: Peer-Led or Teacher-Led?

    OpenAIRE

    Stephenson, Judith; Strange, Vicki; Allen, Elizabeth; Copas, Andrew; Johnson, Anne; Bonell, Chris; Babiker, Abdel; Oakley, Ann

    2008-01-01

    Editors' Summary Background. Teenage pregnancies are fraught with problems. Children born to teenage mothers are often underweight, which can affect their long-term health; young mothers have a high risk of poor mental health after the birth; and teenage parents and their children are at increased risk of living in poverty. Little wonder, then, that faced with one of the highest teenage pregnancy rates in Western Europe, the Department of Health in England launched a national Teenage Pregnanc...

  7. A comparison of midwife-led care versus obstetrician-led care for low-risk women in Japan.

    Science.gov (United States)

    Iida, Mariko; Horiuchi, Shigeko; Nagamori, Kumiko

    2014-09-01

    Continuity of midwife-led care is recommended in maternity care because of its various positive outcomes. In Japan, midwife-led care is receiving broad attention as well. In order to popularise midwifery care within the entire system of perinatal care in Japan, there is a need to show evidence that continuity of midwife care for women will bring about positive outcomes. The objectives of this study were to compare the health outcomes of women and infants who received midwife-led care with obstetrician-led care in Japan. This was an observational study using non-random purposive sampling with a survey questionnaire. Settings where midwife-led care and obstetrician-led care were chosen by purposive samples. Participants were low-risk women who received antenatal care and delivered a term-singleton-infant at the participating settings during the research period. Measurements were: Women-centred care pregnancy questionnaire, Stein's maternity blues questionnaire, and Edinburgh Postnatal Depression Scale. Midwife-led care was perceived by women to be beneficial and had no adverse outcomes compared to obstetrician-led care. Main findings are: (1) Perception of Women-centred care was higher; (2) Less premature rupture of membranes, and the Apgar scores of the infants were similar; (3) Exclusively breast-feeding during hospitalisation and at one-month postpartum; (4) Stein's maternity blues scale scores was lower in women who received midwife-led care than those who received obstetrician-led care. Continuity of midwife-led care was perceived by women to be beneficial and had no adverse outcomes. Therefore, midwife-led care in low-risk pregnancy could be applicable and recommended. Copyright © 2014 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

  8. Effect of UV irradiation on the apoptosis and necrosis of Jurkat cells using UV LEDs

    Science.gov (United States)

    Inada, Shunko A.; Amano, Hiroshi; Akasaki, Isamu; Morita, Akimichi; Kobayashi, Keiko

    2009-02-01

    Phototherapy is a very effective method for treating most of the incurable skin diseases. A fluorescent light bulb is used as a conventional UV light source for this type of therapy. However, infrared radiation from the light source sometimes causes serious problems on patient's health. In addition, the normal part of the skin is irradiated when a large fluorescent light bulb is used. Moreover, a conventional UV irradiation system is heavy and has a short lifetime and a high electrical power consumption. Therefore, a new UV light source for solving the problems of phototherapy is required. To realize low-power-consumption, lightweight and long-lifetime systems, group III nitride-based UV-A1 light-emitting diodes (LEDs) were investigated. We examined the UV LED irradiation of Jurkat cell, which is a tumor cell and more sensitive to UV light than a healthy cell. The numbers of apoptotic and necrotic cells were confirmed to be the same using a UV LED and a conventional lamp system. The UV LED showed the possibility of realizing a new UV light source for phototherapy.

  9. Monte carlo analysis of multicolour LED light engine

    DEFF Research Database (Denmark)

    Chakrabarti, Maumita; Thorseth, Anders; Jepsen, Jørgen

    2015-01-01

    A new Monte Carlo simulation as a tool for analysing colour feedback systems is presented here to analyse the colour uncertainties and achievable stability in a multicolour dynamic LED system. The Monte Carlo analysis presented here is based on an experimental investigation of a multicolour LED...

  10. Thermo-mechanical model optimization of HB-LED packaging

    NARCIS (Netherlands)

    Yuan, C.A.; Erinc, M.; Gielen, A.W.J.; Waal, A. van der; Driel, W. van; Zhang, K.

    2011-01-01

    Lighting is an advancing phenomenon both on the technology and on the market level due to the rapid development of the solid state lighting technology. The efforts in improving the efficacy of high brightness LED's (HB-LED) have concentrated on the packaging architecture. Packaging plays a

  11. Tuning the color point of a white LED

    NARCIS (Netherlands)

    Adhikary, Manashee; Meretska, Maryna; Ladovrechis, K.; Fokkema, Wouter K.; Vissenberg, Gilles; Lagendijk, Ad; Ijzerman, W.L.; Vos, Willem L.

    2018-01-01

    White light is conveniently characterized by a color point that is represented on the color space. Color point of white LED is fixed by the design parameters (e.g. Phosphor type and concentration). When the design parameters are chosen, the color point of the white LED cannot be changed. Here, we

  12. The Lifetime Prediction of LED Drivers and Lamps

    NARCIS (Netherlands)

    Sun, B.

    2017-01-01

    Light-Emitting Diodes (LEDs) have become a very promising alternative lighting source with the main advantages of a longer lifetime and a higher efficiency than traditional ones. However, the LED lamp’s lifetime is compromised by its driver’s reliability. Although extensive studies have been made on

  13. Development of an intelligent integrated LED system-in-package

    NARCIS (Netherlands)

    Gielen, A.W.J.; Hesen, P.; Swartjes, F.H.M.; Zeijl, H. van; Boschman, F.; Bullema, J.-E.; Werkhoven, R.J.; Koh, S.

    2011-01-01

    Intelligent LED lighting systems can save up to 80% of energy compared to traditional lighting systems. In order to provide these intelligent lighting products at reaseonable costs, integration and miniaturisation are important steps. To this end we have designed a LED system-in-package that

  14. Assessment of community led total sanitation uptake in rural Kenya ...

    African Journals Online (AJOL)

    Background: Community Led Total Sanitation (CLTS) is an innovative community led drive to set up pit latrines in rural Kenya with an aim of promoting sustainable sanitation through behaviour change. It's a behaviour change approach based on social capital that triggers households to build pit latrines without subsidy.

  15. Led enhancement in mitochondrial oxidative phosphorylation for hepatectomized rats

    Directory of Open Access Journals (Sweden)

    Orlando de Castro-e-Silva Jr

    2002-01-01

    Full Text Available Recently, the LED (light emitting diode developed by the Optics Group of IFSC-USP has been used instead of laser for the treatment of skin tumors by the PDT (Photodinamic Therapy because of its low operational cost compared to the use of a laser. In this paper we investigate the effect of LED light on oxidative phosphorylation during liver regeneration after partial hepatectomy. Twenty-four male Wistar rats (250 g were kept in identical housing units on a 12-hour light/12 hour dark cycle. The LED 10 group was exposed to LED at 638 nm (10 J/cm² for 3 minutes. Seventy percent partial hepatectomy was performed in the LED 10 and HPC (Partial Hepatectomy-Control. A sham-operated group (C was used for control. Twenty four hours after the procedure, LED 10, HPC and control animals were sacrificed. Samples of liver tissue were used for the mitochondrial respiration assay. Statistical comparisons of the groups were performed by analysis of variance (ANOVA, followed by the Bonferroni post-test. Probability values less than 0.05 were considered to be statistically significant. the phosphorylation index (FI for the LED 10 group was higher than that for the HPC group and for the sham group (p 0.05. In the present study we noted an effective interaction between LED light and hepatic mitochondria, with an increased phosphorylation rate for the latter.

  16. Transport of Light Through White-LED Phosphor Plates

    NARCIS (Netherlands)

    Meretska, Maryna; Thyrrestrup Nielsen, Henri; Lagendijk, Aart; Tukker, Teus; Mosk, Allard; IJzerman, Wilbert; Vos, Willem L.; Di Bartolo, Baldassare; Collins, John; Silvestri, Luciano

    2017-01-01

    Energy efficient generation of white light has become an important societal issue in recent years. The technology of white-light emitting diodes (LEDs) is one of the main directions (Akasaki I, Amano H, Nakamura S, Blue LEDs – filling the world with new light, http://www.nobelprize.org/, 2014;

  17. Transport of light through white-LED phosphor plates

    NARCIS (Netherlands)

    Meretska, Maryna; Thyrrestrup, H.; Lagendijk, Ad; Tukker, T. W.; Mosk, A. P.; IJzerman, W. L.; Vos, Willem L.

    2017-01-01

    Energy efficient generation of white light has become an important societal issue in recent years. The technology of white-light emitting diodes (LEDs) is one of the main directions (Akasaki I, Amano H, Nakamura S, Blue LEDs – filling the world with new light, http://www.nobelprize.org/, 2014;

  18. LED roadway lighting, volume 2 : field evaluations and software comparisons.

    Science.gov (United States)

    2012-10-01

    The use of light-emitting diodes (LEDs) for roadway lighting can potentially save energy costs and reduce the frequency of maintenance. The objective of this study is to explore the current state of the art in LED roadway lighting technology. Three s...

  19. The WIMSE-E module W-LED

    International Nuclear Information System (INIS)

    Roth, M.J.

    1992-06-01

    This report describes the WIMS-E edit module W-LED. W-LED sets up a library of cross section and other nuclear data for a set of materials for subsequent use in a whole reactor program such as PANTHER. (author)

  20. Thermal analysis of LED lamps for optimal driver integration

    NARCIS (Netherlands)

    Perpiñà, X.; Werkhoven, R.J.; Vellvehi, M.; Jakovenko, J.; Jordà, X.; Kunen, J.M.G.; Bancken, P.; Bolt, P.J.

    2015-01-01

    This paper studies the thermal influence of a light-emitting diode (LED) driver on a retrofit LED lamp, also reporting on a procedure for its thermal characterization and multiscale modeling. In this analysis, temperature is measured by infrared thermography and monitoring specific locations with

  1. Student-Led Parent Conferences: A Model for Teaching Responsibility.

    Science.gov (United States)

    Guyton, Jane M.; Fielstein, Lynda L.

    1989-01-01

    Describes program in which elementary school students lead parent-teacher conferences, shares authors' experiences with the student-led conferences, and discusses how the process has fostered student responsibility. Describes results of informal study that support the student-led conference. (NB)

  2. Low Cost Lithography Tool for High Brightness LED Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Andrew Hawryluk; Emily True

    2012-06-30

    The objective of this activity was to address the need for improved manufacturing tools for LEDs. Improvements include lower cost (both capital equipment cost reductions and cost-ofownership reductions), better automation and better yields. To meet the DOE objective of $1- 2/kilolumen, it will be necessary to develop these highly automated manufacturing tools. Lithography is used extensively in the fabrication of high-brightness LEDs, but the tools used to date are not scalable to high-volume manufacturing. This activity addressed the LED lithography process. During R&D and low volume manufacturing, most LED companies use contact-printers. However, several industries have shown that these printers are incompatible with high volume manufacturing and the LED industry needs to evolve to projection steppers. The need for projection lithography tools for LED manufacturing is identified in the Solid State Lighting Manufacturing Roadmap Draft, June 2009. The Roadmap states that Projection tools are needed by 2011. This work will modify a stepper, originally designed for semiconductor manufacturing, for use in LED manufacturing. This work addresses improvements to yield, material handling, automation and throughput for LED manufacturing while reducing the capital equipment cost.

  3. Shortest exposure time possible with LED curing lights

    NARCIS (Netherlands)

    Busemann, I.; Lipke, C.; Schattenberg, A.V.M.B.; Willershausen, B.; Ernst, C.P.

    2011-01-01

    PURPOSE: To investigate the shortest exposure time of different light emitting diode (LED)-curing devices for different resin composites in a clinically relevant laboratory model. METHODS: Nine LED curing devices (Bluephase, Bluephase 16i, Bluephase G2, Bluephase 20i/Ivoclar Vivadent, DEMI/sds Kerr,

  4. The effect of LED illumination on endodontic biofilms

    DEFF Research Database (Denmark)

    Markvart, Merete

    nm) and UVC (266nm) region. The PDT was applied using the commercial product Fotosan®. The UV LEDs were able to eliminate the E. faecalis biofilm while the PDT was only able to make a reduction in the total number of viable cells. UV LEDs may improve disinfection procedures during root canal...

  5. Luminous flux and colour maintenance investigation of integrated LED lamps

    DEFF Research Database (Denmark)

    Corell, Dennis Dan; Thorseth, Anders; Dam-Hansen, Carsten

    2014-01-01

    This article will present an investigation of the luminous flux and colour maintenance of white LED based retrofit lamps. The study includes 23 different types of integrated LED lamps, covering 18 directional and 5 non-directional. Luminous flux and colour data for operation up to 20000 h has been...

  6. Design of LED lamps | Ashryatov | Journal of Fundamental and ...

    African Journals Online (AJOL)

    The variant of the lighting system energy efficiency increase with luminaires and linear fluorescent lamps is considered. In the proposed variant, the fluorescent lamps and start regulating devices are replaced with linear LED modules. In order to reduce the glossiness of a luminaire, the LED modules must be covered with ...

  7. Improved power quality based high brightness LED lamp driver ...

    African Journals Online (AJOL)

    This paper deals with a power factor corrected (PFC) improved power quality based LED lamp driver. The proposed driver consists of a PFC Cuk DC-DC converter which operates in continuous conduction mode (CCM) to improve the power quality at input AC mains. The design, modeling and simulation of an 18W LED (six ...

  8. Physiological and genetic characterization of plant growth and gravitropism in LED light sources

    Science.gov (United States)

    Deitzer, Gerald F.

    1994-01-01

    Among the many problems of growing plants in completely controlled environments, such as those anticipated for the space station and the CELSS program, is the need to provide light that is both adequate for photosynthesis and of proper quality for normal growth and development. NASA scientists and engineers have recently become interested in the possibility of utilizing densely packed, solid state, light emitting diodes (LED's) as a source for this light. Unlike more conventional incandescent or electrical discharge lamps, these sources are highly monochromatic and lack energy in spectral regions thought to be important for normal plant development. In addition, a recent observation by NASA scientist has suggested that infra-red LED's, that are routinely used as photographic safelights for plants grown in darkness, may interact with the ability of plants to detect gravity. In order to establish how plants respond to light from these LED light sources we carried out a series of experiments with known pigment mutants of the model mustard plant, Arabidopsis thaliana, growing in either a gravity field or on a clinostat to simulate a micro-gravity environment. Results indicate that only red light from the 665 nm LED's disrupts the ability of normal wildtype seedlings to detect a gravity stimulus. There was no consistent effect found for the far-red (735 nm) LED's or either of the infrared (880 nm or 935 nm) LED sources but both showed some effect in one or more of the genotypes tested. Of these five members of the phytochrome multigene family in Arabidopsis, only the phytochrome B pigment mutant (hy3) lacked the ability to detect gravity under all conditions. There was no effect of either micro-gravity (clinostat) or the infra-red LED's on the light induced inhibition of hypocotyl elongation. Measurements of the pigment phytochrome in oats also showed no photoconversion by 15 min irradiations with the infra-red LED's. We conclude that phytochrome B is required for the

  9. Indoor visual positioning system using LED and mobile phone

    Science.gov (United States)

    Gong, Yingkui; Shi, Zhengfa; Wang, Yuqi

    2016-01-01

    An indoor visual positioning system is proposed, which using four or more LED ceiling lamps and a mobile phone. A 4*4 photodiode array is attached to the mobile phone to receive the three-dimensional coordinates of the LED lamps via visible light communication, and the front camera of the mobile phone is used to receive the high resolution image of the LED lamps. The mobile phone's three-dimensional coordinates can be determined by matching the spot information and three-dimensional coordinates of the LED lamps with the image information provided by the mobile phone. An improved collinear equation model is proposed to build the mapping relationship between the three-dimensional coordinates of the LED lamps and the image information acquired by the front camera. A semi-physical simulation has been conducted and analyzed. The positioning scheme is proved to be valid and the positioning accuracy is up to decimeter level.

  10. Investigation of irradiance efficiency for LED phototherapy with different arrays

    Science.gov (United States)

    Chen, Hsi-Chao; Wu, Guo-Yang

    2010-12-01

    Red and yellow light emitting diodes (LEDs) are currently utilized as lighting sources during LED phototherapy. These LEDs were arranged on a disk with an external diameter of 70 mm with different arrays — radial, rhombus, square radial, and square rhombus arrays. The radial and square radial arrays had better irradiance efficiency than rhombus and square rhombus arrays by optical simulation. Additionally, the radial array had 76 sets of LEDs, but the square radial array had 100 sets. Thus, a mockup sample of radial array phototherapy was constructed for performance tests. The mixture efficiency of the radial array was observed at distances of 1-100 mm and lighting was well mixed when distance exceeded 50 mm by optical simulation. Irradiance variation with angle was approximated by experiment and theory at a treatment distance of 50 mm and 100 mm using the phototherapy mockup. The radial array was one good choice for LED phototherapy.

  11. The LED monitoring system of the PHOENICS experiment

    International Nuclear Information System (INIS)

    Urban, D.

    1991-07-01

    The PHOENICS experiment at ELSA uses a LED monitoring system to control pulse height and time measurement with scintillation counters. A green LED is mounted at the light guide of each of the 304 involved photomultiplier tubes. The LEDs are driven by fast voltage pulses of 5 ns FWHM width and about 20 V amplitude. Simulation of single events is possible by computer controlled switching of individual LEDs. In order to correct for the temperature dependence of the LED intensity an automatic temperature recording system was coupled to the computer. This monitor system allows to control the pulse height and time measurement with an accuracy of about 2% and 100 ps respectively. (orig.) [de

  12. The African National Congress Led Government's (In)ability to Counter Public Corruption: A Forensic Criminological Perspective

    OpenAIRE

    Setlhomamaru Dintwe

    2012-01-01

    Since the advent of democracy in 1994, there has been a myriad of incidents of corruption involving the public servants in South Africa. Equally so, the government led by the African National Congress have developed various mechanisms aimed at dealing with the problem of corruption. The incidents of corruption, characterized by colossal thefts,  embezzlements and rampant bribery are the basis of erudition around the ability of the African National Congress led government in dealing with corru...

  13. Progress in extremely high brightness LED-based light sources

    Science.gov (United States)

    Hoelen, Christoph; Antonis, Piet; de Boer, Dick; Koole, Rolf; Kadijk, Simon; Li, Yun; Vanbroekhoven, Vincent; Van De Voorde, Patrick

    2017-09-01

    Although the maximum brightness of LEDs has been increasing continuously during the past decade, their luminance is still far from what is required for multiple applications that still rely on the high brightness of discharge lamps. In particular for high brightness applications with limited étendue, e.g. front projection, only very modest luminance values in the beam can be achieved with LEDs compared to systems based on discharge lamps or lasers. With dedicated architectures, phosphor-converted green LEDs for projection may achieve luminance values up to 200-300 Mnit. In this paper we report on the progress made in the development of light engines based on an elongated luminescent concentrator pumped by blue LEDs. This concept has recently been introduced to the market as ColorSpark High Lumen Density LED technology. These sources outperform the maximum brightness of LEDs by multiple factors. In LED front projection, green LEDs are the main limiting factor. With our green modules, we now have achieved peak luminance values of 2 Gnit, enabling LED-based projection systems with over 4000 ANSI lm. Extension of this concept to yellow and red light sources is presented. The light source efficiency has been increased considerably, reaching 45-60 lm/W for green under practical application conditions. The module architecture, beam shaping, and performance characteristics are reviewed, as well as system aspects. The performance increase, spectral range extensions, beam-shaping flexibility, and cost reductions realized with the new module architecture enable a breakthrough in LED-based projection systems and in a wide variety of other high brightness applications.

  14. Designing low cost LED display for the billboard

    Science.gov (United States)

    Hong, Yi-Jian; Uang, Chii-Maw; Wang, Ping-Chieh; Ho, Zu-Sheng

    2011-10-01

    With quickly advance of the computer, microelectronics and photonics technologies, LED display panel becomes a new electronic advertising media. It can be used to show any information whatever characters or graphics. Most LED display panels are built of many Light-Emitting Diodes arranged in a matrix form. The display has many advantages such as low power, low cost, long life and high definition. Because the display panel is asked to show rich color, the LED display panel's driving system becomes very complex. The design methodology of LED display panel's driver becomes more and more important to meet the market requirements. Cost is always the most important issue in public market domain. In this paper, we report a design methodology of LED display panel's driver based on the microprocessor control unit (MCU) system and LED display controller IC, HT1632C, to control three colors, RGB, color LED display panel and the modular panel size is 24*16 in matrix form. The HT1632C is a memory mapping LED display controller, it can be used on many applications, such as digital clock, thermometer, counter, voltmeter or other instrumentation readouts. Three pieces of HT1632C are used to drive a 24*16 RGB LED display panel, in our design case. Each HT163C chip is used to control one of the R, G and B color. As the drive mode is driven in DC mode, the RGB display panel can create and totally of seven colors under the control of MCU. The MCU generates the control signal to drive HT1632C. In this study, the software design methodology is adopted with dynamic display principle. When the scan frequency is 60Hz, LED display panel will get the clear picture and be able to display seven colors.

  15. Peer-led and professional-led group interventions for people with co-occurring disorders: a qualitative study.

    Science.gov (United States)

    Pallaveshi, Luljeta; Balachandra, Krishna; Subramanian, Priya; Rudnick, Abraham

    2014-05-01

    This pilot study evaluated the experience of people with co-occurring disorders (mental illness and addiction) in relation to peer-led and professional-led group interventions. The study used a qualitative (phenomenological) approach to evaluate the experience of a convenience sample of 6 individuals with co-occurring disorders who participated in up to 8 sessions each of both peer-led and professional-led group interventions (with a similar rate of attendance in both groups). The semi-structured interview data were coded and thematically analyzed. We found 5 themes within and across the 2 interventions. In both groups, participants experienced a positive environment and personal growth, and learned, albeit different things. They were more comfortable in the peer-led group and acquired more knowledge and skills in the professional-led group. Offering both peer-led and professional-led group interventions to people with co-occurring disorders may be better than offering either alone.

  16. Evaluation of parameters of color profile models of LCD and LED screens

    Science.gov (United States)

    Zharinov, I. O.; Zharinov, O. O.

    2017-12-01

    The purpose of the research relates to the problem of parametric identification of the color profile model of LCD (liquid crystal display) and LED (light emitting diode) screens. The color profile model of a screen is based on the Grassmann’s Law of additive color mixture. Mathematically the problem is to evaluate unknown parameters (numerical coefficients) of the matrix transformation between different color spaces. Several methods of evaluation of these screen profile coefficients were developed. These methods are based either on processing of some colorimetric measurements or on processing of technical documentation data.

  17. Novel thin-GaN LED structure adopted micro abraded surface to compare with conventional vertical LEDs in ultraviolet light

    Science.gov (United States)

    Chiang, Yen Chih; Lin, Chien Chung; Kuo, Hao Chung

    2015-04-01

    In this study, novel thin-GaN-based ultraviolet light-emitting diodes (NTG-LEDs) were fabricated using wafer bonding, laser lift-off, dry etching, textured surface, and interconnection techniques. Placing PN electrodes on the same side minimized the absorption caused by electrodes in conventional vertical injection light-emitting diodes (V-LEDs) and the current spreading was improved. The light output power (700 mA) of the NTG-LEDs was enhanced by 18.3% compared with that of the V-LEDs, and the external quantum efficiency (EQE) of the NTG-LEDs was also relatively enhanced by 20.0% compared with that of a reference device. When the current operations were 1,500 mA, the enhancements of the light output power and EQE were 27.4% and 27.2%, respectively. Additionally, the efficiency droop was improved by more than 15% at the same current level.

  18. Effect of electrophotographic processes on print quality in LED printers

    Science.gov (United States)

    Wyhof, John R.

    1990-08-01

    The advantage of LED electrophotographic page printers is closely linked to the the process parameters of the printer. The electrical and mechanical processes and material properties were analyzed with respect to the affect on the print quality. Most critical to the print quality for the LED array printer is the constancy of the light intensity since the elements in the array are each independent light sources. It was found that the spot size can change significantly if the light intensity varies. Halftone printing uses the spot size to space size ratio to create the grayscale. The light intensity variation between elements can be 20 in non-compensated LED head arrays. If the need for light intensity compensation can be eliminated then a significant cost reduction in the LED head can be achieved. However the parameters of the basic electrophotographic processes must be carefully selected to assure a constant spot size and optimum print quality. The development method toner properties and the portion of the photoreceptor discharge curve used have the strongest influence on the spot size and halftone print quality. Transfer fusing and mechanical parameters have minimal effect. 1. LED PRINTING PROCESS The advantages of the LED printing process for high speed electrophotographic printers are well known. 1 Recently several printer manufacturers have introduced electrophotographic LED printers in the lower speed range. When compared to the scanning laser beam or liquid crystal

  19. Reliability test and failure analysis of high power LED packages

    Science.gov (United States)

    Zhaohui, Chen; Qin, Zhang; Kai, Wang; Xiaobing, Luo; Sheng, Liu

    2011-01-01

    A new type application specific light emitting diode (LED) package (ASLP) with freeform polycarbonate lens for street lighting is developed, whose manufacturing processes are compatible with a typical LED packaging process. The reliability test methods and failure criterions from different vendors are reviewed and compared. It is found that test methods and failure criterions are quite different. The rapid reliability assessment standards are urgently needed for the LED industry. 85 °C/85 RH with 700 mA is used to test our LED modules with three other vendors for 1000 h, showing no visible degradation in optical performance for our modules, with two other vendors showing significant degradation. Some failure analysis methods such as C-SAM, Nano X-ray CT and optical microscope are used for LED packages. Some failure mechanisms such as delaminations and cracks are detected in the LED packages after the accelerated reliability testing. The finite element simulation method is helpful for the failure analysis and design of the reliability of the LED packaging. One example is used to show one currently used module in industry is vulnerable and may not easily pass the harsh thermal cycle testing.

  20. Spectral design flexibility of LED brings better life

    Science.gov (United States)

    Ou, Haiyan; Corell, Dennis; Ou, Yiyu; Poulsen, Peter B.; Dam-Hansen, Carsten; Petersen, Paul-Michael

    2012-03-01

    Light-emitting diodes (LEDs) are penetrating into the huge market of general lighting because they are energy saving and environmentally friendly. The big advantage of LED light sources, compared to traditional incandescent lamps and fluorescent light tubes, is the flexible spectral design to make white light using different color mixing schemes. The spectral design flexibility of white LED light sources will promote them for novel applications to improve the life quality of human beings. As an initial exploration to make use of the spectral design flexibility, we present an example: 'no blue' white LED light source for sufferers of disease Porphyria. An LED light source prototype, made of high brightness commercial LEDs applying an optical filter, was tested by a patient suffering from Porphyria. Preliminary results have shown that the sufferer could withstand the light source for much longer time than the standard light source. At last future perspectives on spectral design flexibility of LED light sources improving human being's life will be discussed, with focus on the light and health. The good health is ensured by the spectrum optimized so that vital hormones (melatonin and serotonin) are produced during times when they support human daily rhythm.

  1. [Study on the safety of blue light leak of LED].

    Science.gov (United States)

    Shen, Chong-Yu; Xu, Zheng; Zhao, Su-Ling; Huang, Qing-Yu

    2014-02-01

    In this paper, the blue light properties of LED illumination devices have been investigated. Against the status quo of China's LED lighting, we measured the spectrum component of LED lamps and analyzed the photobiological safety under the current domestic and international standards GB/T 20145-2006/CIE S009/E: 2002 and IEC62471: 2006 standards as well as CTL-0744_2009-laser resolution, which provides the reference to the manufacture of LED lighting lamps as well as related safety standards and laws. If the radiance intensity of blue light in LED is lower than 100 W x m(-2) x Sr(-1), there is no harm to human eyes. LEDs will not cause harm to human eyes under normal use, but we should pay attention to the protection of special populations (children), and make sure that they avoid looking at a light source for a long time. The research has found that the blue-rich lamps can affect the human rule of work and rest, and therefore, the LED lamps with color temperature below 4 000 K and color rendering index of 80 are suitable for indoor use. At the same time, the lamps with different parameters should be selected according to the different distances.

  2. Visual color matching system based on RGB LED light source

    Science.gov (United States)

    Sun, Lei; Huang, Qingmei; Feng, Chen; Li, Wei; Wang, Chaofeng

    2018-01-01

    In order to study the property and performance of LED as RGB primary color light sources on color mixture in visual psychophysical experiments, and to find out the difference between LED light source and traditional light source, a visual color matching experiment system based on LED light sources as RGB primary colors has been built. By simulating traditional experiment of metameric color matching in CIE 1931 RGB color system, it can be used for visual color matching experiments to obtain a set of the spectral tristimulus values which we often call color-matching functions (CMFs). This system consists of three parts: a monochromatic light part using blazed grating, a light mixing part where the summation of 3 LED illuminations are to be visually matched with a monochromatic illumination, and a visual observation part. The three narrow band LEDs used have dominant wavelengths of 640 nm (red), 522 nm (green) and 458 nm (blue) respectively and their intensities can be controlled independently. After the calibration of wavelength and luminance of LED sources with a spectrophotometer, a series of visual color matching experiments have been carried out by 5 observers. The results are compared with those from CIE 1931 RGB color system, and have been used to compute an average locus for the spectral colors in the color triangle, with white at the center. It has been shown that the use of LED is feasible and has the advantages of easy control, good stability and low cost.

  3. Vision communications based on LED array and imaging sensor

    Science.gov (United States)

    Yoo, Jong-Ho; Jung, Sung-Yoon

    2012-11-01

    In this paper, we propose a brand new communication concept, called as "vision communication" based on LED array and image sensor. This system consists of LED array as a transmitter and digital device which include image sensor such as CCD and CMOS as receiver. In order to transmit data, the proposed communication scheme simultaneously uses the digital image processing and optical wireless communication scheme. Therefore, the cognitive communication scheme is possible with the help of recognition techniques used in vision system. By increasing data rate, our scheme can use LED array consisting of several multi-spectral LEDs. Because arranged each LED can emit multi-spectral optical signal such as visible, infrared and ultraviolet light, the increase of data rate is possible similar to WDM and MIMO skills used in traditional optical and wireless communications. In addition, this multi-spectral capability also makes it possible to avoid the optical noises in communication environment. In our vision communication scheme, the data packet is composed of Sync. data and information data. Sync. data is used to detect the transmitter area and calibrate the distorted image snapshots obtained by image sensor. By making the optical rate of LED array be same with the frame rate (frames per second) of image sensor, we can decode the information data included in each image snapshot based on image processing and optical wireless communication techniques. Through experiment based on practical test bed system, we confirm the feasibility of the proposed vision communications based on LED array and image sensor.

  4. Sociale problemer

    DEFF Research Database (Denmark)

    Christensen, Anders Bøggild; Rasmussen, Tove; Bundesen, Peter Verner

    række fagfolk på tværs af det danske socialfaglige felt fokus på sociale problemer. Det diskuteres, hvad vi overhovedet forstår ved sociale problemer, hvordan de opstår, hvilke konsekvenser de har, og ikke mindst hvordan man som fagprofessionel håndterer sociale problemer i det daglige arbejde. Bogen er...... skrevet som lærebog til professionsuddannelser, hvor sociale problemer udgør en dimension, bl.a. socialrådgiver-, pædagog- og sygeplejerskeuddannelserne....

  5. LED lamps in shipboard lighting systems: Aspects of electromagnetic compatibility

    Directory of Open Access Journals (Sweden)

    Beley V. F.

    2016-12-01

    Full Text Available Trends in the development of different types of light sources and their energy characteristics have been described in the paper. Analysis of regulatory documents has been given. The results of experimental studies of a number of modern LED lamps have been described. Investigation has been made for a number of LED lamps produced by Philips, Xavax and Melitec. The experimental data have been obtained with the complex of devices: the dual-channel oscilloscope (GDS-71042, the power quality analyzer (Fluke-434 and the multi-function device EcoLight-01 (light-, pulse- and luminance meter. It has been shown that operation of LED lamps is characterized by emission of higher current harmonics and reactive power consumption, which depends on the type and design of the lamp driver. It has been found that the value of luminance created by LED lamps in case of acceptable (for ships prolonged deviation of voltage (–10 % is reduced by 3 %; in case of permissible short-term voltage deviation (–20 % luminance is reduced by 7 %. For incandescent lamps this indicator is characterized by a decrease in luminance by 40 % and 60 %, respectively. Despite the low sensitivity to voltage changes (in comparison with other types of lamps, the operation of LED lamps is also associated with the appearance of flicker. Absence of limitations for fluctuations of the light flux in shipboard lighting systems and imperfection of methods for determining the flicker make it difficult to ensure electromagnetic compatibility of LED lamps. Therefore due to reliability, environmental friendliness, energy efficiency and lumen maintenance LED lamps have prospects for introduction into shipboard lighting systems. However, to ensure electromagnetic compatibility of LED lighting systems it is necessary to conduct a detailed study of energy characteristics of LED lamps and to develop appropriate regulatory requirements and technical solutions.

  6. Evaluating UV-C LED disinfection performance and ...

    Science.gov (United States)

    This study evaluated ultraviolet (UV) light emitting diodes (LEDs) emitting at 260 nm, 280 nm, and the combination of 260|280 nm together for their efficacy at inactivating Escherichia. coli, MS2 coliphage, human adenovirus type 2 (HAdV2), and Bacillus pumilus spores; research included an evaluation of genomic damage. Inactivation by the LEDs was compared with the efficacy of conventional UV sources, the low-pressure (LP) and medium-pressure (MP) mercury vapor lamps. The work also calculated the electrical energy per order of reduction of the microorganisms by the five UV sources.For E. coli, all five UV sources yielded similar inactivation rates. For MS2 coliphage, the 260 nm LED was most effective. For HAdV2 and B. pumilus, the MP UV lamp was significantly more effective than the LP UV and UVC LED sources. When considering electrical energy per order of reduction, the LP UV lamp was the most efficient for E. coli and MS2, and the MPUV and LPUV were equally efficient for HAdV2 and B. pumilus spores. Among the UVC LEDs, the 280 nm LED unit required the least energy per log reduction of E. coli and HAdV2. The 280 nm and 260|280 nm LED units were equally efficient per log reduction of B. pumilus spores, and the 260 nm LED unit required the lowest energy per order of reduction of MS2 coliphage. The combination of the 260 nm and 280 nm UV LED wavelengths was also evaluated for potential synergistic effects. No dual-wavelength synergy was detected for inactivation of

  7. LOW-COST LED LUMINAIRE FOR GENERAL ILLUMINATION

    Energy Technology Data Exchange (ETDEWEB)

    Lowes, Ted

    2014-07-31

    During this two-year Solid-State Lighting (SSL) Manufacturing R&D project Cree developed novel light emitting diode (LED) technologies contributing to a cost-optimized, efficient LED troffer luminaire platform emitting at ~3500K correlated color temperature (CCT) at a color rendering index (CRI) of >90. To successfully achieve program goals, Cree used a comprehensive approach to address cost reduction of the various optical, thermal and electrical subsystems in the luminaire without impacting performance. These developments built on Cree’s high- brightness, low-cost LED platforms to design a novel LED component architecture that will enable low-cost troffer luminaire designs with high total system efficacy. The project scope included cost reductions to nearly all major troffer subsystems as well as assembly costs. For example, no thermal management components were included in the troffer, owing to the optimized distribution of compact low- to mid-power LEDs. It is estimated that a significant manufacturing cost savings will result relative to Cree’s conventional troffers at the start of the project. A chief project accomplishment was the successful development of a new compact, high-efficacy LED component geometry with a broad far-field intensity distribution and even color point vs. emission angle. After further optimization and testing for production, the Cree XQ series of LEDs resulted. XQ LEDs are currently utilized in Cree’s AR series troffers, and they are being considered for use in other platforms. The XQ lens geometry influenced the independent development of Cree’s XB-E and XB-G high-voltage LEDs, which also have a broad intensity distribution at high efficacy, and are finding wide implementation in Cree’s omnidirectional A-lamps.

  8. Éalonnage de sources lumineuses de type LED

    DEFF Research Database (Denmark)

    Durix, Bastien; Quéau, Yvain; Lucas, Tom

    We describe three calibration methods of a LED (light-emitting diode), in order to apply photometric stereo to a scene illuminated by LEDs. The most accurate of these methods will allow us to obtain very realistic 3D models. Nevertheless, the scene must remain still during the whole shooting...... sequence. We thus extend this method to a LED model which takes into account the color of the light flow. This will allow us to perform photometric stereo from a unique colored image of a scene, if it is simultaneously illuminated with three colored light flows....

  9. The Role of Documentation in Practice-Led Research

    OpenAIRE

    Nithikul Nimkulrat

    2007-01-01

    Practice-led research in the field of art and design usually involves a study of the interplay between a researcher-practitioner and her artistic work in process. This article seeks to illustrate that documentation of art practice can be a means to record that interplay and it can be used as relevant material in practice-led research. The article will present an account of documentation in practice-led research highlighting two principal aspects: phases of documentation and the role of docume...

  10. Adapting research activity: AHRC review of practice-led research

    OpenAIRE

    Till, J; Mottram, J; Rust, C

    2005-01-01

    In 2005 the Arts and Humanities Research Council initiated a review of practice-led research in art, design and architecture. The purpose of the review was to develop a ‘comprehensive map of recent and current research activity in the area’. What quickly became obvious to the team that won the bid to run the review (led by the three authors) was that to map activity one first had to attempt to define it. The term ‘practice-led research’ means many different things to different people and so i...

  11. University of Nevada Las Vegas LED Display Engineering

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-08-31

    The primary objective of this part of the project is to develop and implement a method that compensates for the inefficiency of the green LED. The proposed engineering solution which will be the backbone of this project will be to use RGBW combination in every pixel to save energy. Two different RGBW geometrical pixel configurations will be implemented and compared against traditional LED configurations. These configurations will be analyzed for energy efficiency while keeping the quality of the display the same. Cost of the addition of white LEDs to displays along with energy cost savings will be presented and analyzed.

  12. Optimized Phosphors for Warm White LED Light Engines

    Energy Technology Data Exchange (ETDEWEB)

    Setlur, Anant; Brewster, Megan; Garcia, Florencio; Hill, M. Christine; Lyons, Robert; Murphy, James; Stecher, Tom; Stoklosa, Stan; Weaver, Stan; Happek, Uwe; Aesram, Danny; Deshpande, Anirudha

    2012-07-30

    The objective of this program is to develop phosphor systems and LED light engines that have steady-state LED efficacies (using LEDs with a 60% wall-plug efficiency) of 105–120 lm/W with correlated color temperatures (CCT) ~3000 K, color rendering indices (CRI) >85, <0.003 distance from the blackbody curve (dbb), and <2% loss in phosphor efficiency under high temperature, high humidity conditions. In order to reach these goals, this involves the composition and processing optimization of phosphors previously developed by GE in combination with light engine package modification.

  13. Comparative life cycle assessment of LED lighting products

    OpenAIRE

    Casamayor, JL; Su, D; Ren, Z

    2017-01-01

    LED lighting products used in lighting applications and their subsequent environmental impact are growing rapidly. However, there are no in-depth updated studies that show how to assess and compare them for eco-design purposes. This research aims to add insights in this area to inform eco-design by assessing and comparing the environmental impact of a new LED eco-lighting product with an existing LED lighting product. A cradle to grave Life Cycle assessment (LCA) was conducted using ReCiPe Mi...

  14. High Output LED-Based Profile Lighting Fixture

    DEFF Research Database (Denmark)

    Török, Lajos; Beczkowski, Szymon; Munk-Nielsen, Stig

    2011-01-01

    Recent developments in power light emitting diode (LED) industry have made LEDs suitable for being efficiently used in high intensity lighting fixtures instead of the commonly used high intensity discharge (HID) lamps. A high output LEDbased profile-light fixture is presented in this paper...... the grid and delivers the required voltage to the LEDdriver which is a dual interleaved buck converter. Twelve highpower CBT-90 LEDs have been connected in a 4xRGBconfiguration to deliver high output of saturated colors without the need for subtractive color filters. More than 6000 lm of fixture light...

  15. Iluminación LED. Un arma de doble filo

    OpenAIRE

    Sánchez de Miguel, Alejandro

    2004-01-01

    La iluminación LED es el futuro de la iluminación. Sin embargo, como toda tecnología, puede usarse de manera correcta o incorrecta. En el caso de los LED, el abaratamiento de la producción de luz podría provocar un aumento descontrolado de la Contaminación lumínica. Por otro, el uso correcto de los LED podría ser la solución al mismo mal por su capacidad de encendido casi instantáneo.

  16. High power LEDs - technology status and market applications

    International Nuclear Information System (INIS)

    Steranka, F.M.; Bhat, J.; Collins, D.; Cook, L.; Craford, M.G.; Fletcher, R.; Gardner, N.; Grillot, P.; Goetz, W.; Keuper, M.; Khare, R.; Kim, A.; Krames, M.; Harbers, G.; Ludowise, M.; Martin, P.S.; Misra, M.; Mueller, G.; Mueller-Mach, R.; Rudaz, S.; Shen, Y.C.; Steigerwald, D.; Subramanya, S.; Trottier, T.; Wierer, J.J.

    2002-01-01

    High power light emitting diodes (LEDs) continue to increase in output flux with the best III-nitride based devices today emitting over 150 lm of white, cyan, or green light. The key design features of such products will be covered with special emphasis on power packaging, flip-chip device design, and phosphor coating technology. The high-flux performance of these devices is enabling many new applications for LEDs. Two of the most interesting of these applications are LCD display backlighting and vehicle forward lighting. The advantages of LEDs over competing lighting technologies will be covered in detail. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

  17. PENGEMBANGAN LAMPU LED DENGAN TEKNOLOGI PHOTOVOLTAIC (LED-PV SEBAGAI ALAT BANTU PENGUMPUL IKAN PADA PERIKANAN BAGAN

    Directory of Open Access Journals (Sweden)

    Mochamad Arief Sofijanto

    2015-03-01

    mengetahui perbedaan jumlah hasil tangkapan pada bagan tancap akibat perlakuan warna lampu LED yang berbeda. Metode penelitian yang digunakan adalah deskriptif dan experimental fishing dimana rancangan penelitiannya adalah Rancangan Acak Lengkap (RAL dengan perlakuan warna lampu LED sebanyak 5 jenis warna yaitu merah (A, kuning (B, hijau (C, biru (D, dan putih (E dengan 6 kali ulangan. Secara deskriptif hasil penelitian menunjukkan lampu LED dapat digunakan untuk menggantikan lampu petromaks dan lampu LHE. Diperoleh 17 jenis ikan laut yang tertarik pada cahaya lampu LED yang digunakan. Hasil analisis statistik menunjukkan terdapat perbedaan nyata terhadap hasil tangkapan bagan dengan perlakuan warna lampu LED. Berdasarkan Uji Nyata Terkecil dinyatakan bahwa bagan yang menggunakan warna lampu LED biru mendapatkan hasil tangkapan tertinggi kemudian diikuti oleh warna kuning, hijau, putih dan merah.  The set ‘bagan’ (liftnet fishing gear is a kind of fishing gears which using atificial light as fishes gathering. This fishing gear uses an electric generator to turn on the energy saving lamp which hang on under the set ‘bagan’. The price of gasoline more expensive due to the Indonesia government’s fuel subsidy reduced and this make fishing operation costs more expensive for fishermen. This research using the LED lamps that do not use gasoline as fuel because the LED lamps can use the photovoltaic technology (solar cell system. The purposes of this study were: 1 to find out whether the LED lamps can replace the kerosene lamps and saving energy lamps, 2 to know the different in cath using different colours of LED lamps. The reserach methods are descriptive and experimental fishing which used Completely Randomized Design with LED lamps colour treatments i.e: red (A, yellow (B, green (C, blue (D, and white (E, the number of replications are 6 times. LED lamps can be used to replace the kerosene and saving energy lamps. There were 17 species of

  18. Comparison of milk oxidation by exposure to LED and fluorescent light.

    Science.gov (United States)

    Brothersen, C; McMahon, D J; Legako, J; Martini, S

    2016-04-01

    Light-induced oxidation of milk has been well studied. Exposure of milk to UV light facilitates the oxidation of fats to aldehydes, and the degradation of sulfur-containing amino acids, both of which contribute to off-flavors. In addition, vitamin A and riboflavin are easily degraded by UV light. These reactions occur rapidly and are exacerbated by bright fluorescent lights in retail dairy cases. The invention of white light-emitting diodes (LED) may provide a solution to this oxidation problem. In this study, fresh milk containing 1% fat and fortified with vitamin A and riboflavin was exposed to LED at 4,000 lx, or fluorescent light at 2,200 lx for 24 h. Milk samples exposed to LED or fluorescent light, as well as milk protected from light, were analyzed by a consumer acceptance panel, and a trained flavor panel. In addition, vitamin A, riboflavin, and the production of volatile compounds were quantified. Exposure to light resulted in a reduction of cooked/sweet, milkfat, and sweet flavors and increased the intensity of butterscotch, cardboard, and astringency. In general, exposure to fluorescent light resulted in greater changes in the milk than exposure to LED even though the LED was at higher intensity. Consumers were able detect off-flavors in milk exposed to fluorescent light after 12 h and LED after 24 h of exposure. The riboflavin and vitamin A content was reduced by exposure to fluorescent light, whereas there was no significant reduction caused by LED compared with the non-light-exposed control. Production of hexanal, heptanal, 2-heptanal, octanal, 2-octanal nonanal, dimethyl sulfide, and caproic acid vinyl ester from the light-induced degradation of fats was significantly higher with fluorescent than LED. Production of these compounds was significantly higher with both light treatments than in the control milk. This study indicates that LED is less destructive to milk than fluorescent light. Copyright © 2016 American Dairy Science Association. Published

  19. Foot Problems

    Science.gov (United States)

    ... can also cause foot problems. The Most Common Types of Foot Problems In older adults, the foot complaints encountered ... people include: Arch pain . From fallen arches (flat feet), or abnormally high arches. Tarsal tunnel syndrome . A type of pinched nerve disorder. Achilles tendonitis . Inflammation of ...

  20. Problem Periods

    Science.gov (United States)

    ... during your menstrual cycle Premenstrual syndrome (PMS) Problem periods Getting enough sleep Looking and feeling your best Fighting germs Your sexuality What are STDs and STIs? Seeing the doctor Quizzes Links to more information on girls' bodies girlshealth glossary girlshealth.gov home http://www.girlshealth.gov/ Home ... Problem periods It’s common to have ...

  1. The Role of Documentation in Practice-Led Research

    Directory of Open Access Journals (Sweden)

    Nithikul Nimkulrat

    2007-01-01

    Full Text Available Practice-led research in the field of art and design usually involves a study of the interplay between a researcher-practitioner and her artistic work in process. This article seeks to illustrate that documentation of art practice can be a means to record that interplay and it can be used as relevant material in practice-led research. The article will present an account of documentation in practice-led research highlighting two principal aspects: phases of documentation and the role of documentation within the overall research process. The account will capture reflections of the author’s own practice-led research in fiber art, which investigates the relationship between materials and artistic expression, in the context of contemporary art.

  2. Effect of Led Lighting Colors for Laying Japanese Quails

    Directory of Open Access Journals (Sweden)

    KC Nunes

    Full Text Available ABSTRACT Time of exposure and light intensity rearing house may affect the performance and egg quality of laying quails. This research aimed at evaluating the live performance, egg quality, biometry of the reproductive system, and the gastrointestinal tract of Japanese quails (Coturnix coturnix japonica exposed to artificial light-emitting diodes (LED of different colors in comparison with fluorescent lamps. A total of 240 Japanese quails were distributed in completely randomized experimental design with four treatments (fluorescent lamp, and green, red, or blue LED lamps with six replicates of 10 birds each. Average egg weight and eggshell thickness were different (p0.05. The oviduct of 64-d-old hens exposed to green LED lighting was shorter (p<0.05 than those exposed to the fluorescent lamp. Red LED can be used to replace the fluorescent lamps, as they promote the same live performance, egg quality, and morphological development of the reproductive tract of laying Japanese quails.

  3. LED lamp incorporating remote phosphor with heat dissipation features

    Science.gov (United States)

    Tong, Tao; Letoquin, Ronan; Keller, Bernd; Tarsa, Eric

    2016-11-22

    An LED lamp or bulb is disclosed that comprises a light source, a heat sink structure and a remote planar phosphor carrier having at least one conversion material. The phosphor carrier can be remote to the light sources and mounted to the heat sink so that heat from the phosphor carrier spreads into the heat sink. The phosphor carrier can comprise a thermally conductive transparent material and a phosphor layer, with an LED based light source mounted to the heat sink such that light from the light source passes through the phosphor carrier. At least some of the LED light is converted by the phosphor carrier, with some lamp embodiments emitting a white light combination of LED and phosphor light. The phosphor arranged according to the present invention can operate at lower temperature to thereby operate at greater phosphor conversion efficiency and with reduced heat related damage to the phosphor.

  4. Medical students' learning from patient-led teaching

    DEFF Research Database (Denmark)

    Henriksen, Ann-Helen; Ringsted, Charlotte

    2014-01-01

    a patient-centred approach, and acknowledged the importance of the PIs' individual perspectives and experiential knowledge. On the other hand, representing the scientific biomedical perspective and traditional step-by step teaching, students expressed unfamiliarity with the unstructured experiential......The aim of this study was to explore how medical students perceive the experience of learning from patient instructors (patients with rheumatism who teach health professionals and students) in the context of coupled faculty-led and patient-led teaching session. This was an explorative study...... learning and scepticism regarding the credibility of the patients' knowledge. This study contributes to the understanding of the complexity of involving patients as teachers in healthcare education and initiates a discussion on how to complement faculty-led teaching with patient-led teaching involving...

  5. Microbial raw data for UV-C LED disinfection study

    Data.gov (United States)

    U.S. Environmental Protection Agency — This study evaluated ultraviolet (UV) light emitting diodes (LEDs) emitting at 260 nm, 280 nm, and the combination of 260|280 nm together for their efficacy at...

  6. 76 FR 66692 - Executive-Led Trade Mission to Afghanistan

    Science.gov (United States)

    2011-10-27

    ... its market economy and increase both domestic and foreign private investment. GIRoA continues to... DEPARTMENT OF COMMERCE International Trade Administration Executive-Led Trade Mission to Afghanistan AGENCY: International Trade Administration, Department of Commerce. ACTION: Notice. Mission...

  7. Laboratory Evaluation of LED T8 Replacement Lamp Products

    Energy Technology Data Exchange (ETDEWEB)

    Richman, Eric E.; Kinzey, Bruce R.; Miller, Naomi J.

    2011-05-23

    A report on a lab setting analysis involving LED lamps intended to directly replace T8 fluorescent lamps (4') showing light output, power, and economic comparisons with other fluorescent options.

  8. LED Retrofit Kits, TLEDs, and Lighting Controls: An Application Guide

    Energy Technology Data Exchange (ETDEWEB)

    None

    2017-03-01

    This document provides guidance for retrofitting existing fluorescent troffers including the LED and associated control options available, the pro/cons and costs/benefits of each option, and agency specific requirements (where applicable).

  9. Integrated parabolic nanolenses on MicroLED color pixels

    Science.gov (United States)

    Demory, Brandon; Chung, Kunook; Katcher, Adam; Sui, Jingyang; Deng, Hui; Ku, Pei-Cheng

    2018-04-01

    A parabolic nanolens array coupled to the emission of a nanopillar micro-light emitting diode (LED) color pixel is shown to reduce the far field divergence. For a blue wavelength LED, the total emission is 95% collimated within a 0.5 numerical aperture zone, a 3.5x improvement over the same LED without a lens structure. This corresponds to a half-width at half-maximum (HWHM) line width reduction of 2.85 times. Using a resist reflow and etchback procedure, the nanolens array dimensions and parabolic shape are formed. Experimental measurement of the far field emission shows a HWHM linewidth reduction by a factor of 2x, reducing the divergence over the original LED.

  10. Light Emitting Diode (LED) circular traffic signal lifetime management system.

    Science.gov (United States)

    2011-02-01

    The objective of this research is to build lifetime curves for red, yellow, and green LED circular traffic signals through 20,000-hr. accelerated stress testing of samples operating under Louisianas environmental conditions.

  11. LED phototherapy improves healing of nipple trauma: a pilot study.

    Science.gov (United States)

    Chaves, Maria Emília de Abreu; Araújo, Angélica Rodrigues; Santos, Suellen Fonsêca; Pinotti, Marcos; Oliveira, Leandro Soares

    2012-03-01

    The purpose of this study was to evaluate the clinical effectiveness of a LED phototherapy prototype apparatus in the healing of nipple trauma in breastfeeding women. There is no scientific evidence of an effective treatment for nipple trauma. The experimental group was treated with orientation on nipple care and adequate breastfeeding techniques in addition to active LED phototherapy. The control group was treated with orientation on nipple care and adequate breastfeeding techniques in addition to placebo LED phototherapy. Participants were treated twice a week, for a total of eight sessions. Healing of the nipple lesions was measured by a reduction in their area, and decrease in pain intensity was measured in accordance with an 11-point Pain Intensity Numerical Rating Scale and a standard 7-point patient global impression of change. Statistically significant reductions in measured nipple lesion area (pLED phototherapy to be an effective tool in accelerating the healing of nipple trauma.

  12. Spectral Design Flexibility of LED Brings Better life

    DEFF Research Database (Denmark)

    Ou, Haiyan; Corell, Dennis Dan; Ou, Yiyu

    2012-01-01

    white light using different color mixing schemes. The spectral design flexibility of white LED light sources will promote them for novel applications to improve the life quality of human beings. As an initial exploration to make use of the spectral design flexibility, we present an example: 'no blue...... longer time than the standard light source. At last future perspectives on spectral design flexibility of LED light sources improving human being's life will be discussed, with focus on the light and health. The good health is ensured by the spectrum optimized so that vital hormones (melatonin......Light-emitting diodes (LEDs) are penetrating into the huge market of general lighting because they are energy saving and environmentally friendly. The big advantage of LED light sources, compared to traditional incandescent lamps and fluorescent light tubes, is the flexible spectral design to make...

  13. A new LED light source for display cases

    DEFF Research Database (Denmark)

    Dam-Hansen, Carsten; Petersen, Paul Michael

    Abstract: We report a new LED light source suitable for illumination of gold objects. It has a variable correlated color temperature from 2760 K to 2200 K with a high color rendering index up to 97.......Abstract: We report a new LED light source suitable for illumination of gold objects. It has a variable correlated color temperature from 2760 K to 2200 K with a high color rendering index up to 97....

  14. Narratives of making:thinking practice led research in architecture

    OpenAIRE

    Ramsgaard Thomsen, Mette; Tamke, Martin

    2009-01-01

    Practice led research methods investigate their line of inquiries from within a knowledge of doing. The practice is an incorporated skill set, a working method in which the practitioner is trained. The recent focus on practice led research method acknowledges practice as a means of gaining new knowledge. Efforts across the field of practice based research seek to develop means for engaging with issues such as critical assessment, comparability and evaluation. This paper presents research unde...

  15. Biological Research in Canisters (BRIC) - Light Emitting Diode (LED)

    Science.gov (United States)

    Levine, Howard G.; Caron, Allison

    2016-01-01

    The Biological Research in Canisters - LED (BRIC-LED) is a biological research system that is being designed to complement the capabilities of the existing BRIC-Petri Dish Fixation Unit (PDFU) for the Space Life and Physical Sciences (SLPS) Program. A diverse range of organisms can be supported, including plant seedlings, callus cultures, Caenorhabditis elegans, microbes, and others. In the event of a launch scrub, the entire assembly can be replaced with an identical back-up unit containing freshly loaded specimens.

  16. An Integrated Solid-State LED Luminaire for General Lighting

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Dowling; Fritz Morgan Ihor Lys; Mike Datta; Bernd Keller; Thomas Yuan

    2009-03-31

    A strong systems approach to designing and building practical LED-based replacement lamps is lacking. The general method of taking high-performance LEDs and marrying them to standard printed circuit boards, drivers and a heat sink has fallen short of the promise of LED lighting. In this program, a top-down assessment of requirements and a bottom-up reinvention of LED sources, electronics, optics and mechanics have resulted in the highest performance lamp possible. The team, comprised of Color Kinetics, the leaders in LED lighting and Cree, the leaders in LED devices took an approach to reinvent the package, the driver and the overall form and aesthetic of a replacement source. The challenge was to create a new benchmark in LED lighting - the resultant lamp, a PAR38 equivalent, met the light output, color, color quality and efficacy marks set out in the program as well as being dimmable, which is important for market acceptance. The approach combined the use of multiple source die, a chip-on-board approach, a very efficient driver topology, the use of both direct emission and phosphor conversion, and a unique faceted optic to avoid the losses, artifacts and hotspots of lensed approaches. The integral heat sink provided a mechanical base and airflow using a chimney-effect for use in a wide variety of locations and orientations. These research results led to a much better understanding of the system effects of component level technologies. It was clear that best-of-breed sub-system results do not necessarily result in the best end result for the complete system. In doing this work, we did not neglect the practical aspects of these systems. These were not rarified results and commercially impractical but lent themselves to eventual commercial products in the marketplace. The end result - a high performance replacement lamp - will save significant energy while providing a high-quality light source.

  17. Integrated LED-based luminaire for general lighting

    Science.gov (United States)

    Dowling, Kevin J.; Lys, Ihor A.; Williamson, Ryan C.; Roberge, Brian; Roberts, Ron; Morgan, Frederick; Datta, Michael Jay; Mollnow, Tomas Jonathan

    2016-08-30

    Lighting apparatus and methods employing LED light sources are described. The LED light sources are integrated with other components in the form of a luminaire or other general purpose lighting structure. Some of the lighting structures are formed as Parabolic Aluminum Reflector (PAR) luminaires, allowing them to be inserted into conventional sockets. The lighting structures display beneficial operating characteristics, such as efficient operation, high thermal dissipation, high output, and good color mixing.

  18. Integrated LED-based luminare for general lighting

    Science.gov (United States)

    Dowling, Kevin J.; Lys, Ihor A.; Roberge, Brian; Williamson, Ryan C.; Roberts, Ron; Datta, Michael; Mollnow, Tomas; Morgan, Frederick M.

    2013-03-05

    Lighting apparatus and methods employing LED light sources are described. The LED light sources are integrated with other components in the form of a luminaire or other general purpose lighting structure. Some of the lighting structures are formed as Parabolic Aluminum Reflector (PAR) luminaires, allowing them to be inserted into conventional sockets. The lighting structures display beneficial operating characteristics, such as efficient operation, high thermal dissipation, high output, and good color mixing.

  19. Protection against methanol-induced retinal toxicity by LED photostimulation

    Science.gov (United States)

    Whelan, Harry T.; Wong-Riley, Margaret T. T.; Eells, Janis T.

    2002-06-01

    We have initiated experiments designed to test the hypothesis that 670-nm Light-Emitting Diode (LED) exposure will attenuate formate-induced retinal dysfunction in a rodent model of methanol toxicity. Methanol intoxication produces toxic injury to the retina. The toxic metabolite formed in methanol intoxication is formic acid, a mitochondrial toxin known to inhibit cytochrome oxidase activity. 670-nm LED light has been hypothesized to act by stimulating cytochrome oxidase activity. To test this hypothesis, one group of animals was intoxicated with methanol, a second group was intoxicated with methanol and LED-treated and a third group was untreated. LED treatment (670 nm for 1 min 45 seconds equals 50 mW/cm2, 4 joules/cm2) was administered at 5, 25, and 50 hours after the initial dose of methanol. At 72 hours of methanol intoxication, retinal function was assessed by measurement of ERG responses and retinas were prepared for histologic analysis. ERG responses recorded in methanol-intoxicated animals revealed profound attenuation of both rod-dominated and UV-cone mediated responses. In contrast, methanol- intoxicated animals exposed to LED treatment exhibited a nearly complete recovery of rod-dominated ERG responses and a slight improvement of UV-cone mediated ERG responses. LED treatment also protected the retina against the histopathologic changes produced by formate in methanol intoxication. These data provide evidence that LED phototherapy protects the retina against the cytotoxic actions of formate and are consistent with the hypothesis that LED photostimulation improves mitochondrial respiratory chain function.

  20. LED lighting combined with solar panels in developing countries

    OpenAIRE

    Amogpai, Ater

    2011-01-01

    The aim of the work was to find out the functionality of LED lighting combined with solar panels in developing countries and to find out the availability of solar energy in different geographical locations. Another aim of the work was to understand the advantages and disadvantages of photovoltaic systems and the optimum combination of PV systems for lighting. Measurements of photovoltaic systems combined with LEDs and fluorescent lighting were conducted in an office building in Finland. ...

  1. Optimal colour quality of LED clusters based on memory colours.

    Science.gov (United States)

    Smet, Kevin; Ryckaert, Wouter R; Pointer, Michael R; Deconinck, Geert; Hanselaer, Peter

    2011-03-28

    The spectral power distributions of tri- and tetrachromatic clusters of Light-Emitting-Diodes, composed of simulated and commercially available LEDs, were optimized with a genetic algorithm to maximize the luminous efficacy of radiation and the colour quality as assessed by the memory colour quality metric developed by the authors. The trade-off of the colour quality as assessed by the memory colour metric and the luminous efficacy of radiation was investigated by calculating the Pareto optimal front using the NSGA-II genetic algorithm. Optimal peak wavelengths and spectral widths of the LEDs were derived, and over half of them were found to be close to Thornton's prime colours. The Pareto optimal fronts of real LED clusters were always found to be smaller than those of the simulated clusters. The effect of binning on designing a real LED cluster was investigated and was found to be quite large. Finally, a real LED cluster of commercially available AlGaInP, InGaN and phosphor white LEDs was optimized to obtain a higher score on memory colour quality scale than its corresponding CIE reference illuminant.

  2. LED Street Lighting Solutions: Flagstaff, Arizona as a Case Study

    Science.gov (United States)

    Hall, Jeffrey C.

    2018-01-01

    Dark-sky protection in Flagstaff, Arizona extends back to 1958, with the first ordinance in the City banning advertising floodlights. The current ordinance, adopted in 1989, is comprehensive and has played a critical role in maintaining the quality of the night sky for astronomy, tourism, public enjoyment, and other purposes. Flagstaff, like many communities around the world, is now working on a transition from legacy bulb-based technology to LED for its outdoor lighting. The City, Lowell Observatory, the U. S. Naval Observatory, and the Flagstaff Dark Skies Coalition have been working intensively for two years to identify an LED-based street lighting solution that will preserve the City's dark skies while meeting municipal needs. We will soon be installing test fixtures for an innovative solution incorporating narrow-band amber LED and modest amounts of low-CCT white LED. In this talk, I will review the types of LEDs available for outdoor lighting and discuss the plans for Flagstaff's street lighting in the LED era, which we hope will be a model for communities worldwide.

  3. UV-LEDs Efficiently Inactivate DNA and RNA Coliphages

    Directory of Open Access Journals (Sweden)

    Alyaa M. Zyara

    2017-01-01

    Full Text Available UV-LEDs are a new method of disinfecting drinking water. Some viruses are very resistant to UV and the efficiency of UV-LEDs to disinfect them needs to be studied. Drinking water was disinfected with UV-LEDs after spiking the water with MS2 and four UV- and/or Cl-resistant coliphages belonging to RNA or DNA coliphages isolated from municipal wastewater. UV-LEDs operating at a wavelength of 270 nm for 2 min with 120 mW of irradiation caused 0.93–2.73 Log10-reductions of coliphages tested in a reactor of a 5.2 L volume. Irradiation time of 10 min in the same system increased the Log10-reductions to 4.30–5.16. Traditional mercury UV (Hg-UV lamp at a 254 nm wavelength caused 0.67–4.08 Log10-reductions in 2 min and 4.56–7.21 Log10-reductions in 10 min in 10 mL of water. All coliphages tested except MS2 achieved 4 Log10-reductions with UV-LEDs at a dose that corresponded to 70 mWs/cm2 using Hg-UV. Thus, UV-LEDs are a promising method of disinfecting UV- and/or Cl-resistant viruses.

  4. LED lighting and the Next Generation of Greenhouse for Tomatoes. Proof of Principle; LED belichting en Het Nieuwe Telen bij tomaat. Proof of Principle

    Energy Technology Data Exchange (ETDEWEB)

    Dueck, T.; Janse, J.; Eveleens, B. [Wageningen UR Glastuinbouw, Wageningen (Netherlands); Nieboer, S.; Valstar, W.; Grootscholten, M. [GreenQ Improvement Centre, Bleiswijk (Netherlands)

    2012-08-15

    In this Proof of Principle project a tomato crop was grown under artificial lighting with the aim of 30% energy saving at the same level of production. Tomatoes (cultivar Komeett) were illuminated with 110 {mu}mol m{sup -2} s{sup -1} HPS (High Pressure Sodium) above the crop and 85 {mu}mol m{sup -2} s{sup -1} LED interlighting. The LEDs hung in 2 rows, approximately 40 cm above the lower leaves and the second strand at 40 or 70 cm above that. There were two types of LEDs used: production LEDs (light efficiency 1.6 {mu}mol m{sup -2} s{sup -1}, 87% red/13% blue) and inter-lighting LEDs (light efficiency 1.9 {mu}mol m{sup -2} s{sup -1}, 95% red/5% blue), with the same light intensity. At the start, the crop was given as much light as it could handle, and because the crop developed so well, the stem density was increased relatively early. This resulted in high fruit load, while insufficient light was available to compensate for the low levels of sunlight in the winter. In the 192 cm row spacing system the plants were too close to each other. Additional problems occurred with trace elements, lesser bumble bee activity, and a moist greenhouse climate which weakened the crop in the winter. Thus Botrytis occurred on the leaves and stems. The crop struggled with its recovery until early spring with more sunlight. Compared to a reference crop with 79 kg m{sup -2} tomatoes, 75 kg m{sup -2} were produced under-production LEDs, and 80 kg m{sup -2} under the interlighting LEDs, mainly because latter LEDs were used longer during the summer. 30% of the energy for dehumidification and heat energy, and 27% of the electricity was saved, relative to the reference crop. Thus it appears possible to save 30% energy with a near identical production [Dutch] In dit Proof of Principle project is een belichte tomatenteelt geteeld met als doel 30% energiebesparing bij een gelijke productie. Tomaten van het ras Komeett werden belicht met 110 {mu}mol m{sup -2} s{sup -1} SON-T belichting boven

  5. Applied Mathematical Problems in Engineering

    Directory of Open Access Journals (Sweden)

    Carlos Llopis-Albert

    2016-10-01

    Full Text Available There is a close relationship between engineering and mathematics, which has led to the development of new techniques in recent years. Likewise the developments in technology and computers have led to new ways of teaching mathematics for engineering students and the use of modern techniques and methods.  This research aims to provide insight on how to deal with mathematical problems for engineering students. This is performed by means of a fuzzy set/Qualitative Comparative Analysis applied to conflict resolution of Public Participation Projects in support to the EU Water Framework Directive.

  6. Halogen light versus LED for bracket bonding: shear bond strength

    Directory of Open Access Journals (Sweden)

    Paulo Eduardo Guedes Carvalho

    2013-02-01

    Full Text Available INTRODUCTION: LED light-curing devices seek to provide a cold light activator which allows protocols of material polymerization with shorter duration. OBJECTIVE: The present study aimed to evaluate the shear bond strength of bracket bonding using three types of light-curing devices: One with halogen light (Optilight Plus - Gnatus and two with LEDs (Optilight CL - Gnatus and Elipar Freelight - 3M/ESPE. RESULTS: Comparing the results by analysis of variance, the Gnatus LED device showed an inferior statistical behavior in relation to other light sources, when activated by a short time. But, when it was used for 40 seconds, the polymerization results were consistent with the other evaluated sources. The device with the best average performance was the halogen light, followed by the 3M/ESPE LED. CONCLUSION: It was concluded that the LEDs may be indicated in orthodontic practice, as long as a protocol is used for the application of light with the activation time of 40 seconds.INTRODUÇÃO: os aparelhos de fotopolimerização por LED buscam proporcionar uma luz ativadora fria, que possibilite protocolos de polimerização do material com menor tempo de duração. OBJETIVO: avaliar a resistência à tração da colagem de braquetes, utilizando três tipos de aparelhos fotoativadores: um de luz halógena (Optilight Plus - Gnatus e outros dois de LED (Optilight CL - Gnatus; e Elipar Freelight - 3M/Espe. RESULTADOS: comparando os resultados por meio da análise de variância, o aparelho de LED Gnatus apresentou comportamento estatístico inferior em relação às outras fontes de luz, quando ativado por tempo reduzido. Já quando foi utilizado o tempo de 40 segundos, os resultados de polimerização foram compatíveis com as demais fontes avaliadas. O aparelho que apresentou melhor desempenho médio foi o de luz halógena, seguido pelo LED 3M/Espe. CONCLUSÃO: concluiu-se que os LEDs podem ser indicados na prática ortodôntica, uma vez que seja utilizado

  7. Efficacy of embedded nurse-led versus conventional physician-led follow-up in rheumatoid arthritis

    DEFF Research Database (Denmark)

    de Thurah, Annette; Esbensen, Bente Appel; Roelsgaard, Ida Kristiane

    2017-01-01

    -led follow-up on disease control in patients with RA compared with physician-led follow-up. Primary outcome was disease activity indicated by Disease Activity Score (DAS)-28. Secondary outcomes were: patient satisfaction, physical disability, fatigue, self-efficacy and quality of life. Outcomes were assessed......OBJECTIVE: To compare the efficacy of embedded nurse-led versus conventional physician-led follow-up on disease activity in patients with rheumatoid arthritis (RA). METHODS: In a systematic literature search, we identified randomised controlled trials (RCTs) reporting on the efficacy of nurse...... after 1-year and 2 year follow-ups. RESULTS: Seven studies representing five RCTs, including a total of 723 participants, were included. All but one study included stable patients in low disease activity or remission at baseline. No difference in DAS-28 was found after 1 year (mean difference (MD) -0...

  8. Reduction of the thickness of lenticular stereoscopic display using full-color LED panel

    Science.gov (United States)

    Yamamoto, Hirotsugu; Muguruma, Syuji; Hayasaki, Yoshio; Nagai, Yoshifumi; Shimizu, Yoshinori; Nishida, Nobuo

    2002-05-01

    The goals of our research are to realize stereoscopic large displays for the general public in the open air. These goals impose certain design constraints. It is preferable to view stereoscopic images without any special glasses. Multiple viewing areas are necessary to crowds of viewers. The thickness of the stereoscopic large display is a problem for installations. We have developed a stereoscopic full color LED display using parallax barrier and demonstrated multiple viewing areas. However, the thickness of that stereoscopic display, which is consisted of 8-mm pitch LED panel, becomes over 2 min the case that the viewing distance is designed for 20 m. In order to reduce the thickness of stereoscopic LED display, we propose use of dual lenticular sheets. The first lenticular sheet performs multiple imaging, which allows multiple viewing areas without diffusion screen. The second lenticular sheets separates the raster images into the right and left eye positions. The thickness, which is defined as the distance between the LED panel and the second lenticular sheet, can be reduced below 50cm for the viewing distance of 20 m. Optimal parameters are discussed to reduce the thickness.

  9. Development and testing of a homogenous multi-wavelength LED light source

    Science.gov (United States)

    Bolton, Frank J.; Bernat, Amir; Jacques, Steven L.; Levitz, David

    2017-03-01

    Multispectral imaging of human tissue is a powerful method that allows for quantify scattering and absorption parameters of the tissue and differentiate tissue types or identify pathology. This method requires imaging at multiple wavelengths and then fitting the measured data to a model based on light transport theory. Earlier, a mobile phone based multi-spectral imaging system was developed to image the uterine cervix from the colposcopy geometry, outside the patient's body at a distance of 200-300 mm. Such imaging of a distance object has inherent challenges, as bright and homogenous illumination is required. Several solutions addressing this problem were developed, with varied degrees of success. In this paper, several multi-spectral illumination setups were developed and tested for brightness and uniformity. All setups were specifically designed with low cost in mind, utilizing a printed circuit board with surface-mounted LEDs. The three setups include: LEDs illuminating the target directly, LEDs illuminating focused by a 3D printed miniature lens array, and LEDs coupled to a mixing lens and focusing optical system. In order to compare the illumination uniformity and intensity performance two experiments were performed. Test results are presented, and various tradeoffs between the three system configurations are discussed. Test results are presented, and various tradeoffs between the three system configurations are discussed.

  10. Breathing Problems

    Science.gov (United States)

    ... getting enough air. Sometimes you can have mild breathing problems because of a stuffy nose or intense ... panic attacks Allergies If you often have trouble breathing, it is important to find out the cause.

  11. Sleep Problems

    Science.gov (United States)

    ... For Consumers Consumer Information by Audience For Women Sleep Problems Share Tweet Linkedin Pin it More sharing ... 101 KB) En Español Medicines to Help You Sleep Tips for Better Sleep Basic Facts about Sleep ...

  12. Tongue problems

    Science.gov (United States)

    ... Tongue pain may also occur with: Diabetic neuropathy Leukoplakia Mouth ulcers Oral cancer After menopause, some women have ... problem. Medicine may be prescribed for mouth ulcers, leukoplakia, oral cancer, and other mouth sores. Anti-inflammatory medicines ...

  13. Kidney Problems

    Science.gov (United States)

    ... High Blood Pressure Nutrition Join our e-newsletter! Aging & Health A to Z Kidney Problems Basic Facts & ... specialize in the care of people with kidney (renal) diseases are called nephrologists . What are Kidney Diseases? ...

  14. Foot Problems

    Science.gov (United States)

    ... Start OverDiagnosisThese thickened areas are likely to be CORNS. If they appear to have small granules in ... these problems. Self CareUse an over-the-counter corn or wart remover. Remove the dead skin after ...

  15. Instructor-led or Learner-led for Elementary Learners to Learn Computer-based Music Composition?

    OpenAIRE

    Ju-Shih Tseng; Ming-Puu Chen

    2010-01-01

    The purpose of the present study was to examine the effects of instructional strategy (instructor-led vs. learner-led) and grade level (third grade vs. fifth grade) on elementary learners’ music composition performance and attitude with the use of a computer-based music composition software. An experimental learning activity was implemented using 5E learning cycle as a pedagogical framework to facilitate learning. A quasi-experimental design was employed with elementary learners participated ...

  16. Verbaalne soolo Jaanus Nõgistolt : Led R-ist, Narva Linna Sümfooniaorkestrist ja Led Zeppelinist / Jaanus Nõgisto ; interv. Margo Pajuste

    Index Scriptorium Estoniae

    Nõgisto, Jaanus, 1956-

    2007-01-01

    Rockansambli Led Zeppelini muusikast, ansamblist Led R ja heliplaadist "Led the R Out" räägib kitarrist Jaanus Nõgisto. Led R ja Narva Linna Sümfooniaorkestri kontserdid: 22. juunil Pärnus ja 14. juulil Haapsalu lossihoovis, ansambli Led R kontsert koos Havana Blackiga 3. aug. Sõru sadamas Hiiumaal

  17. Popular Problems

    DEFF Research Database (Denmark)

    Skovhus, Randi Boelskifte; Thomsen, Rie

    2017-01-01

    to be’ (WPR) approach. Forty-nine empirical studies on Danish youth career guidance were included in the study. An analysis of the issues in focus resulted in nine problem categories. One of these, ‘targeting’, is analysed using the WPR approach. Finally, the article concludes that the WPR approach...... provides a constructive basis for a critical analysis and discussion of the collective empirical knowledge production on career guidance, stimulating awareness of problems and potential solutions among the career guidance community....

  18. Knapsack problems

    CERN Document Server

    Kellerer, Hans; Pisinger, David

    2004-01-01

    Thirteen years have passed since the seminal book on knapsack problems by Martello and Toth appeared. On this occasion a former colleague exclaimed back in 1990: "How can you write 250 pages on the knapsack problem?" Indeed, the definition of the knapsack problem is easily understood even by a non-expert who will not suspect the presence of challenging research topics in this area at the first glance. However, in the last decade a large number of research publications contributed new results for the knapsack problem in all areas of interest such as exact algorithms, heuristics and approximation schemes. Moreover, the extension of the knapsack problem to higher dimensions both in the number of constraints and in the num­ ber of knapsacks, as well as the modification of the problem structure concerning the available item set and the objective function, leads to a number of interesting variations of practical relevance which were the subject of intensive research during the last few years. Hence, two years ago ...

  19. [The organizational projects management led by head nurses: qualitative study from an educational device.

    Science.gov (United States)

    Dujardin, Pierre-Philippe; Reverdy, Thomas; Valette, Annick; François, Patrice

    2017-09-01

    The work of operational coordination led by head nurses (HN) is more known than their abilities to change work organization, as well as, care practices. In this article, we explore organizational projects led by HN. Depending on the situations, they may concern their health care team or involve institutional hierarchy or other teams. We rely on an intervention study, which enabled us to follow 17 organizational projects led by HN for one year. The results of this study highlight as the main condition for success, the HN' efforts to enable mutual understanding with other interested actors. Managers, who engage their health care team in the development of solutions, bring sustainable results. When problems involve the hierarchy, the managers focus on the development of personal relationships. When problems involve other departments, which they depend on, then they engage themselves into integrative negotiations. These results invite to open discussion about work organization and to formalize organizational projects. This intervention study also points out that work - training at operational audit is relevant for HN. Activé par Editorial Manager® et ProduXion.

  20. Color Maintenance of LEDs in Laboratory and Field Applications

    Energy Technology Data Exchange (ETDEWEB)

    Royer, Michael P.; Tuttle, Ralph; Rosenfeld, Scott M.; Miller, Naomi J.

    2013-09-30

    Synopsis: To date, consideration for parametric failure of LED products has largely been focused on lumen maintenance. However, color shift is a cause of early failure for some products, and is especially important to consider in certain applications, like museums, where visual appearance is critical. Example data collected by the GATEWAY program for LED lamps installed in museums shows that many have changed color beyond a reasonable tolerance well before their rated lifetime was reached, necessitating replacement. Similar data collected by the CALiPER program between 2008 and 2010 reveals that many early products shifted beyond acceptable tolerances in as little as a few thousand hours. In contrast, data from the L Prize program illustrates that commercially available LED products can have exemplary color stability that is unmatched by traditional light sources. Beyond presenting data from the aforementioned DOE programs, this report discusses the metrics used for communicating color shift—namely MacAdam ellipses and Δu'v'—as well as providing guidance for end users on how to monitor color shift and what to look for in manufacturer warranties. Also included are descriptions of the physical changes that have been documented as leading to color shift in some example types of LED packages. As with complete products, the data presented herein for LED packages shows that a wide variety of products are available; in order for specifiers and consumers to make educated choices, more detailed and standardized information should be made available.

  1. Blue laser diode (LD) and light emitting diode (LED) applications

    International Nuclear Information System (INIS)

    Bergh, Arpad A.

    2004-01-01

    The family of blue LEDs, edge emitting and surface emitting lasers, enable a number of applications. Blue lasers are used in digital applications such as optical storage in high density DVDs. The resolution of the spot size and hence the storage density is diffraction limited and is inversely proportional to the square of the wavelength of the laser. Other applications include printing, optical scanners, and high-resolution photo-lithography. As light emitters, blue LEDs are used for signaling and in direct view large area emissive displays. They are also making inroads into signage and LCD back-lighting, mobile platforms, and decorative accent lighting in curtains, furniture, etc. Blue LEDs produce white light either with phosphor wavelength converters or in combination with red and green LEDs. The full potential of LED light sources will require three devices to enable complete control over color and intensity. Sensing and medical/bio applications have a major impact on home security, on monitoring the environment, and on health care. New emerging diagnostic and therapeutic applications will improve the quality and reduce the cost of health care. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Materials and Designs for High-Efficacy LED Light Engines

    Energy Technology Data Exchange (ETDEWEB)

    Ibbetson, James [Cree, Inc., Durham, NC (United States); Gresback, Ryan [Cree, Inc., Durham, NC (United States)

    2017-09-28

    Cree, Inc. conducted a narrow-band downconverter (NBD) materials development and implementation program which will lead to warm-white LED light engines with enhanced efficacy via improved spectral efficiency with respect to the human eye response. New red (600-630nm) NBD materials could result in as much as a 20% improvement in warm-white efficacy at high color quality relative to conventional phosphor-based light sources. Key program innovations included: high quantum yield; narrow peak width; minimized component-level losses due to “cross-talk” and light scattering among red and yellow-green downconverters; and improved reliability to reach parity with conventional phosphors. NBD-enabled downconversion efficiency gains relative to conventional phosphors yielded an end-of-project LED light engine efficacy of >160 lm/W at room temperature and 35 A/cm2, with a correlated color temperature (CCT) of ~3500K and >90 CRI (Color Rending Index). NBD-LED light engines exhibited equivalent luminous flux and color point maintenance at >1,000 hrs. of highly accelerated reliability testing as conventional phosphor LEDs. A demonstration luminaire utilizing an NBD-based LED light engine had a steady-state system efficacy of >150 lm/W at ~3500K and >90 CRI, which exceeded the 2014 DOE R&D Plan luminaire milestone for FY17 of >150 lm/W at just 80 CRI.

  3. LED phototherapy to prevent mucositis: a case report.

    Science.gov (United States)

    Lang-Bicudo, Leticia; Eduardo, Fernanda De Paula; Eduardo, Carlos De Paula; Zezell, Denise Maria

    2008-12-01

    The purpose of this case report was to evaluate the efficacy of phototherapy using light-emitting diodes (LEDs) to prevent oral mucositis in a Hodgkin's disease patient treated with the ABVD (doxorubicin [Adriamycin], bleomycin, vinblastine, and dacarbazine) chemotherapy regimen. Mucositis is a common dose-limiting complication of cancer treatment, and if severe it can lead to alterations in treatment planning or suspension of cancer therapy, with serious consequences for tumor response and survival. Therefore, low-power lasers and more recently LEDs, have been used for oral mucositis prevention and management, with good results. In this study, a 34-year-old man received intraoral irradiation with an infrared LED array (880 nm, 3.6 J/cm2, 74 mW) for five consecutive days, starting on chemotherapy day 1. In each chemotherapy cycle, he received the ABVD protocol on days 1 and 15, and received LED treatment for 5 d during each cycle. To analyze the results, the World Health Organization (WHO) scale was used to grade his mucositis, and a visual analogue scale (VAS) was used for pain evaluation, on days 1, 3, 7, 10, and 13 post-chemotherapy. The results showed that the patient did not develop oral mucositis during the five chemotherapy cycles, and he had no pain symptoms. LED therapy was a safe and effective method for preventing oral mucositis in this case report. However, further randomized studies with more patients are needed to prove the efficacy of this method.

  4. Understanding and controlling chromaticity shift in LED devices

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Lynn; Mills, Karmann; Lamvik, Michael; Perkins, Curtis; Bobashev, Georgiy; Young, Joseph; Yaga, Robert; Johnson, Cortina

    2017-05-30

    Chromaticity shift in light-emitting diode (LED) devices arises from multiple mechanisms, and at least five different chromaticity shift modes (CSMs) have been identified to date. This paper focuses on the impacts of irreversible phosphor degradation as a cause of chromaticity shifts in LED devices. The nitride phosphors used to produce warm white LEDs are especially vulnerable to degradation due to thermal and chemical effects such as reactions with oxygen and water. As a result, LED devices utilizing these phosphors were found to undergo either a green shift or, less commonly, a red shift depending on the phosphor mix in the LED devices. These types of chromaticity shifts are classified as CSM-2 (green shift) and CSM-5 (red shift). This paper provides an overview of the kinetic processes responsible for green and red chromaticity shifts along with examples from accelerated stress testing of 6” downlights. Both CSMs appear to proceed through analogous mechanisms that are initiated at the surface of the phosphor. A green shift is produced by the surface oxidation of the nitride phosphor that changes the emission profile to lower wavelengths. As the surface oxidation reaction proceeds, reactant limitations slow the rate and bulk oxidation processes become more prevalent. We found that a red chromaticity shift arises from quenching of the green phosphor, also possibly due to surface reactions of oxygen, which shift the emission chromaticity in the red direction. In conclusion, we discuss the implications of these findings on projecting chromaticity.

  5. Diversity in sexual health: problems and dilemmas.

    NARCIS (Netherlands)

    Rademakers, J.; Mouthaan, I.; Neef, M. de

    2005-01-01

    The increase in migrant populations in western Europe has led to specific problems and dilemmas in the area of sexual and reproductive health and service provision. In general, these problems and dilemmas can be divided into four categories: (1) epidemiology of diseases and risk factors; (2)

  6. Diversity in sexual health: Problems and dilemmas

    NARCIS (Netherlands)

    Rademakers, J.; Mouthaan, I.; Neef, M. de

    2005-01-01

    The increase in migrant populations in western Europe has led to specific problems and dilemmas in the area of sexual and reproductive health and service provision. In general, these problems and dilemmas can be divided into four categories: (1) epidemiology of diseases and risk factors; (2)

  7. Investigating the baselines of Bismuth, Optical Fiber and LED calibrated photomultiplier tubes

    CERN Document Server

    Evans, Hywel Turner

    2016-01-01

    LUCID is a detector that is the luminosity monitor for the ATLAS experiment, and its aim is to determine luminosity with an uncertainty of a few percent. The main purpose of this work is the study of the baseline stability of the LUCID readout channels during calibration runs. This study represents the first systematic approach of this problem performed by the LUCID group. By replacing the mean baseline with the minimum baseline of each event, an upper limit of 2.85% was placed upon possible improvement in determining the LED amplitude. It is therefore better to use a fixed baseline for LED, as pollution has been observed when calculating event by event. For Bismuth and Fiber, the improvement cannot be more than the gain stability of 1%, therefore the existing method is verified as optimal.

  8. LED Lighting System Reliability Modeling and Inference via Random Effects Gamma Process and Copula Function

    Directory of Open Access Journals (Sweden)

    Huibing Hao

    2015-01-01

    Full Text Available Light emitting diode (LED lamp has attracted increasing interest in the field of lighting systems due to its low energy and long lifetime. For different functions (i.e., illumination and color, it may have two or more performance characteristics. When the multiple performance characteristics are dependent, it creates a challenging problem to accurately analyze the system reliability. In this paper, we assume that the system has two performance characteristics, and each performance characteristic is governed by a random effects Gamma process where the random effects can capture the unit to unit differences. The dependency of performance characteristics is described by a Frank copula function. Via the copula function, the reliability assessment model is proposed. Considering the model is so complicated and analytically intractable, the Markov chain Monte Carlo (MCMC method is used to estimate the unknown parameters. A numerical example about actual LED lamps data is given to demonstrate the usefulness and validity of the proposed model and method.

  9. Numerical simulation and experimental research of the integrated high-power LED radiator

    Science.gov (United States)

    Xiang, J. H.; Zhang, C. L.; Gan, Z. J.; Zhou, C.; Chen, C. G.; Chen, S.

    2017-01-01

    The thermal management has become an urgent problem to be solved with the increasing power and the improving integration of the LED (light emitting diode) chip. In order to eliminate the contact resistance of the radiator, this paper presented an integrated high-power LED radiator based on phase-change heat transfer, which realized the seamless connection between the vapor chamber and the cooling fins. The radiator was optimized by combining the numerical simulation and the experimental research. The effects of the chamber diameter and the parameters of fin on the heat dissipation performance were analyzed. The numerical simulation results were compared with the measured values by experiment. The results showed that the fin thickness, the fin number, the fin height and the chamber diameter were the factors which affected the performance of radiator from primary to secondary.

  10. The role of public libraries in culture-led urban regeneration

    DEFF Research Database (Denmark)

    Skot-Hansen, Dorte; Hvenegaard, Casper; Jochumsen, Henrik

    2013-01-01

    Purpose – The purpose of this article is to present a research project on public libraries in urban development focusing on how libraries contribute to culture‐led urban regeneration as icons, placemakers and community vitalization. Design/methodology/approach – The research project is based......, brand and functions as an answer to strategies of culture‐led urban regeneration, and at the same time they have actively contributed to urban development by changing the image and identity of urban places, contributing to urban diversity and addressing social and economic problems. Practical...... on case studies of new “cutting‐edge” public libraries in Europe and North America. These case studies have been conducted through analysis of documents, observation and qualitative interviews with key informants. Findings – The article finds that new public libraries have re‐conceptualized their design...

  11. [Photoelectric parametric test system of LED based on virtual instrument].

    Science.gov (United States)

    Yang, Song-Tao; Wang, Jing; Wang, Li-Dong; Liang, Pei; Dong, Qian-Min

    2014-11-01

    The standardized measuring principle, requirements and implementations of the above parameters of LEDs were researched and analyzed in the present paper. Then a comprehensive test system involved with optics, machinery and computer was designed to accomplish data acquisition, algorithm design and interface design on virtual instrument using NI data acquisition card USB6210. And convincing results of LEDs' parameters, including peak wavelength, width of half-peak wavelength, centroid wavelength, chromaticity coordinates, purity, correlated color temperature and the forward voltage/current, were achieved with good consistency based on the measured spectrum. The system owns simple interface, reliable algorithms and stable results. Respective measurements on five kinds of color of LED result in an average error less than 3%, which show an ideal performance of the system.

  12. Values-led Participatory Design - Mediating the Emergence of Values

    DEFF Research Database (Denmark)

    Iversen, Ole Sejer; Leong, Tuck Wah

    2012-01-01

    There is a growing interest in values-led inquiries within participatory design. One approach argues that working with values is a recursive 3-phase process that supports the emergence, development and grounding of values. In this paper we focus solely upon the emergence phase, proposing...... an approach that can support the emergence of values during the initial phase of a values-led inquiry. To illustrate this approach and to ground our discussion, we draw from a recent participatory design case where we were engaged in the design of digital technology to support the experiences of young adults...... with severe intellectual disabilities, in an art museum. By describing how we establish, negotiate and the debrief values during this initial phase of a values-led inquiry. By foregrounding both explicit and implicit mediation in the PD process we show how a theoretical understanding of mediation can...

  13. LED-based digital hologram reconstruction by compressive sensing

    Science.gov (United States)

    Weng, Jiawen; Yang, Chuping; Qin, Yi; Li, Hai

    2015-10-01

    LED-based digital hologram, considered as low-coherence digital hologram, is confined to in-line holography because the interference fringes could be observed only when the angle between the object and reference wave is small enough. So, phase-shifting technique is usually employed. But it is not fit for dynamic analysis for demanding more than one hologram. A numerical reconstruction method based on compressive sensing theory for single LED-based digital hologram is proposed to achieve dynamic analysis. By this method, the out-of-focus twin image and the coherent noise can be inhibited to some extent. The theory is presented in detail, and experimental result on LED-based digital holography with USAF pattern as test target, is performed to demonstrate the feasibility and validity of the method.

  14. LED Phototherapy with Gelatin Sponge Promotes Wound Healing in Mice.

    Science.gov (United States)

    Zhang, Heng; Liu, Shupeng; Yang, Xiangfei; Chen, Na; Pang, Fufei; Chen, Zhenyi; Wang, Tingyun; Zhou, Jianshe; Ren, Fuji; Xu, Xiaoyin; Li, Taihao

    2018-01-01

    Tiny but highly efficient, a light-emitting diode (LED) can power a therapy device, such as a phototherapy device, and, at the same time, decrease the device's size requirements. In this study, a LED phototherapy device was designed to investigate the possible impact on wound healing using a mouse model and a cell line exposed to red and blue light. To enhance wound phototherapy, a gelatin sponge was fabricated. Results showed that the red and blue lights promoted cell growth and wound healing, while the blue light with a gelatin sponge protected the wound from infection in the early stages of wound healing. The LED phototherapy device combined with the gelatin sponge, therefore, has potential significance in clinical application for wound healing. © 2017 The American Society of Photobiology.

  15. Self-aligning LED-based optical link

    Science.gov (United States)

    Shen, Thomas C.; Drost, Robert J.; Rzasa, John R.; Sadler, Brian M.; Davis, Christopher C.

    2016-09-01

    The steady advances in light-emitting diode (LED) technology have motivated the use of LEDs in optical wireless communication (OWC) applications such as indoor local area networks (LANs) and communication between mobile platforms (e.g., robots, vehicles). In contrast to traditional radio frequency (RF) wireless communication, OWC utilizes electromagnetic spectrum that is largely unregulated and unrestricted. OWC communication may be especially useful in RF-denied environments, in which RF communication may be prohibited or undesirable. However, OWC does present some challenges, including the need to maintain alignment between potentially moving nodes. We describe a novel system for link alignment that is composed of a hyperboloidal mirror, camera, and gimbal. The experimental system is able to use the mirror and camera to detect an LED beacon of a neighboring node and estimate its bearing (azimuth and elevation), point the gimbal towards the beacon, and establish an optical link.

  16. Developing a nurse-led clinic using transformational leadership.

    Science.gov (United States)

    Gousy, Mamood; Green, Kim

    2015-03-25

    Nurses are at the forefront of implementing and managing change, given constantly changing healthcare services and the increase in demand for health care. Therefore, it is important to identify the best style of leadership to engage nurses in implementing service-led improvements. This article explores the effects of transformational leadership in bringing about service-led improvements in health care, using the example of setting up a nurse-led acupuncture clinic to optimise the care of patients with chronic pain. Transformational leadership was used throughout the project - from the initial local planning, training and development, through to liaising with the appropriate staff and deciding on an evaluation strategy. Transformational leadership proved to be an effective way to engage and empower nurses and other members of the chronic pain team to enable them to achieve the project aims.

  17. InGaN/GaN Nanowire LEDs and Lasers

    KAUST Repository

    Zhao, Chao

    2016-01-01

    The large specific surface, and the associated high density of surface states was found to limit the light output power and quantum efficiency of nanowire-array devices, despite their potential for addressing the “green-gap” and efficiency-droop issues. The phonon and carrier confinement in nanowires also led to junction heating, and reduced heat dissipation. In this paper, we will present our studies on effective surface states passivation in InGaN/GaN quantum-disks (Qdisks)-in-nanowire light-emitting diodes (LEDs) and lasers grown on silicon (Si), as well as our recent work on nanowires LEDs grown on bulk-metal, a non-conventional substrate.

  18. Control and Driving Methods for LED Based Intelligent Light Sources

    DEFF Research Database (Denmark)

    Beczkowski, Szymon

    High power light-emitting diodes allow the creation of luminaires capable of generating saturated colour light at very high efficacies. Contrary to traditional light sources like incandescent and high-intensity discharge lamps, where colour is generated using filters, LEDs use additive light mixing......, where the intensity of each primary colour diode has to be adjusted to the needed intensity to generate specified colour. The function of LED driver is to supply the diode with power needed to achieve the desired intensity. Typically, the drivers operate as a current source and the intensity...... of the diode is controlled either by varying the magnitude of the current or by driving the LED with a pulsed current and regulate the width of the pulse. It has been shown previously, that these two methods yield different effects on diode's efficacy and colour point. A hybrid dimming strategy has been...

  19. LED radiation: possible photobiological risks and safety regulations. Pt. 2

    International Nuclear Information System (INIS)

    Horak, W.

    2008-01-01

    With all due euphoria regarding the new illumination possibilities, one can quite often observe a certain degree of uncertainty concerning eye hazard issues in conjunction with intense LED radiation. Moreover, the related general requirements for product- as well as for workplace-safety are rather new. Thus, the possible hazards by the optical radiation of LEDs will be analyzed in this two-port contribution. Part 1 aims to provide a review of these hazards as well as of the bases for their evaluation. The impact of these requirements on state-of-the-art LEDs will be examined in part 2. Compared with conventional light sources, it turns out that there are hardly any differences in this respect. (orig.)

  20. Calculus problems

    CERN Document Server

    Baronti, Marco; van der Putten, Robertus; Venturi, Irene

    2016-01-01

    This book, intended as a practical working guide for students in Engineering, Mathematics, Physics, or any other field where rigorous calculus is needed, includes 450 exercises. Each chapter starts with a summary of the main definitions and results, which is followed by a selection of solved exercises accompanied by brief, illustrative comments. A selection of problems with indicated solutions rounds out each chapter. A final chapter explores problems that are not designed with a single issue in mind but instead call for the combination of a variety of techniques, rounding out the book’s coverage. Though the book’s primary focus is on functions of one real variable, basic ordinary differential equations (separation of variables, linear first order and constant coefficients ODEs) are also discussed. The material is taken from actual written tests that have been delivered at the Engineering School of the University of Genoa. Literally thousands of students have worked on these problems, ensuring their real-...

  1. Gender-related differences in learning in student-led PBL tutorials.

    Science.gov (United States)

    Kassab, Salah; Abu-Hijleh, Marwan; Al-Shboul, Qasim; Hamdy, Hossam

    2005-07-01

    Male and female students behave differently in problem-based learning (PBL) tutorials. However, these differences could be partly attributed to faculty tutor behavior in male and female tutorials. This study aims to examine the gender differences in learning outcomes between medical students when peer tutors facilitate PBL tutorials. A questionnaire-based study conducted in single-gender student-led (SLT) and faculty-led (FLT) tutorials. The study involved third year medical students (n = 91) divided into ten groups (five groups each). The SLT groups consisted of 16 male and 28 female students, while the FLT group consisted of 20 male and 27 female students. Students evaluated their individual and group performance in tutorials and also skills of tutors. Student performance in end-unit examinations and their perceptions about peer tutoring were also analyzed. A total of 290 questionnaires (response rate = 63.7%) were collected over the five-week period of the study. Although individual performance in tutorials and achievement in examinations were comparable in both groups, there was significantly higher group performance in female compared with male student-led tutorials (p < 0.01). This difference between male and female groups was not attributed to improvement in the performance of female groups, but rather to a decline in performance of the male SLT groups. In addition, both male and female students expressed facing difficulties in discussion and analysis of the problem in the first tutorial session. Understanding the gender differences in the group behavior in student-led tutorials is important for PBL programs adopting this approach.

  2. Determination of organic compounds in water using ultraviolet LED

    Science.gov (United States)

    Kim, Chihoon; Ji, Taeksoo; Eom, Joo Beom

    2018-04-01

    This paper describes a method of detecting organic compounds in water using an ultraviolet LED (280 nm) spectroscopy system and a photodetector. The LED spectroscopy system showed a high correlation between the concentration of the prepared potassium hydrogen phthalate and that calculated by multiple linear regression, indicating an adjusted coefficient of determination ranging from 0.953-0.993. In addition, a comparison between the performance of the spectroscopy system and the total organic carbon analyzer indicated that the difference in concentration was small. Based on the close correlation between the spectroscopy and photodetector absorbance values, organic measurement with a photodetector could be configured for monitoring.

  3. Peer-Led Team Learning Helps Minority Students Succeed.

    Science.gov (United States)

    Snyder, Julia J; Sloane, Jeremy D; Dunk, Ryan D P; Wiles, Jason R

    2016-03-01

    Active learning methods have been shown to be superior to traditional lecture in terms of student achievement, and our findings on the use of Peer-Led Team Learning (PLTL) concur. Students in our introductory biology course performed significantly better if they engaged in PLTL. There was also a drastic reduction in the failure rate for underrepresented minority (URM) students with PLTL, which further resulted in closing the achievement gap between URM and non-URM students. With such compelling findings, we strongly encourage the adoption of Peer-Led Team Learning in undergraduate Science, Technology, Engineering, and Mathematics (STEM) courses.

  4. Remotely Triggered Solar Blind Signaling Using Deep Ultraviolet (UV) LEDs

    Science.gov (United States)

    2011-06-01

    resistance is held constant, the voltage drop across the resistor is also proportional to the amount of light detected. This voltage was measured...distance from the LED to the photodiode was not held constant. To avoid the output voltage limit on the opamp , the intensity of the four HS LEDs was...period for driving voltages up to 8.0 volts. As before, a GaP photodiode was used in conjunction with an opamp , but the output voltage was read with an

  5. Problematic fine bore nasogastric intubation: A radiographer led service development

    International Nuclear Information System (INIS)

    Law, Robert

    2008-01-01

    Developing from the intubation and performing of small bowel enteroclysis a consultant radiographer led service expanded to include problematic gastric, enteric and colonic intubations for diagnostic, therapeutic and interventional purposes. The radiographer led service has also extended to include 'hot reporting' chest images taken to check siting of ward placed nasogastric tubes as well as resiting those tubes that were misplaced. The service has demonstrated itself to be safe and efficient. It has also proven to be both cost and clinically effective. The protracted discomfort and distress to the patient are reduced by minimizing the delay in correctly relocating misplaced tubes

  6. Pharmacist-led medication review in an acute admissions unit

    DEFF Research Database (Denmark)

    Hansen, Trine Graabæk; Bonnerup, Dorthe Krogsgaard; Kjeldsen, Lene Juel

    2015-01-01

    of principles and methodologies, and the practical procedure is seldom described in detail, which makes reproducing study findings difficult. The objective of this paper is to provide a detailed description of a procedure developed and used for pharmacist-led medication review in acute admissions units......) collection of information about the patient's medical treatment, (3) patient interview, (4) critical examination of the patient's medications and (5) recommendations for the hospital physician.Conclusions We have provided a detailed description of a procedure for pharmacist-led medication review. We do so...

  7. New insights into consumer-led food product development

    DEFF Research Database (Denmark)

    Costa, Ana I. A.; Jongen, W.M.F.

    2006-01-01

    industry are described. Contrary to previous optimistic views, it is put forward that without significant changes taking place in the mindset of the organizations involved in Europe's food R&D, the way forward for consumer-led innovation strategies in the agri-business sector will be long and hard.......This paper builds upon a review of relevant marketing, consumer science and innovation management literature to introduce the concept of consumer-led new product development and describe its main implementation stages. The potential shortcomings of this concept's application in European food...

  8. High-Voltage LED Light Engine with Integrated Driver

    Energy Technology Data Exchange (ETDEWEB)

    Soer, Wouter [Lumileds LLC, San Jose, CA (United States)

    2016-02-29

    LED luminaires have seen dramatic changes in cost breakdown over the past few years. The LED component cost, which until recently was the dominant portion of luminaire cost, has fallen to a level of the same order as the other luminaire components, such as the driver, housing, optics etc. With the current state of the technology, further luminaire performance improvement and cost reduction is realized most effectively by optimization of the whole system, rather than a single component. This project focuses on improving the integration between LEDs and drivers. Lumileds has developed a light engine platform based on low-cost high-power LEDs and driver topologies optimized for integration with these LEDs on a single substrate. The integration of driver and LEDs enables an estimated luminaire cost reduction of about 25% for targeted applications, mostly due to significant reductions in driver and housing cost. The high-power LEDs are based on Lumileds’ patterned sapphire substrate flip-chip (PSS-FC) technology, affording reduced die fabrication and packaging cost compared to existing technology. Two general versions of PSS-FC die were developed in order to create the desired voltage and flux increments for driver integration: (i) small single-junction die (0.5 mm2), optimal for distributed lighting applications, and (ii) larger multi-junction die (2 mm2 and 4 mm2) for high-power directional applications. Two driver topologies were developed: a tapped linear driver topology and a single-stage switch-mode topology, taking advantage of the flexible voltage configurations of the new PSS-FC die and the simplification opportunities enabled by integration of LEDs and driver on the same board. A prototype light engine was developed for an outdoor “core module” application based on the multi-junction PSS-FC die and the single-stage switch-mode driver. The light engine meets the project efficacy target of 128 lm/W at a luminous flux

  9. Flicker Reduction in LED-LCDs with Local Backlight

    DEFF Research Database (Denmark)

    Nadernejad, Ehsan; Mantel, Claire; Burini, Nino

    2013-01-01

    Local backlight dimming of LCD with LED backlight can reduce power consumption and improve quality of displayed images and videos. However, important variations of LED over time produce a visually annoying artifact called flickering. In this work, we propose a new algorithm to reduce flickering...... while maintaining video quality. The proposed algorithm uses an adaptive second order Infinite Impulse Response (IIR) in which coefficients are calculated from the local image features. Experimental results show that the proposed method can reduce flickering while simultaneously keeping similar video...

  10. Two phase interleaved buck converter for driving high power LEDs

    DEFF Research Database (Denmark)

    Beczkowski, Szymon; Munk-Nielsen, Stig

    2011-01-01

    The goal of this paper is to evaluate an interleaved buck topology for driving high current light-emitting diodes. Low output capacitor value allows the use of non-electrolytic capacitors extending the lifetime of the converter. Converter is operated as a constant, regulated current source which...... increases luminous efficacy of LED compared to PWM dimmed system. Because of the low dynamic resistance of LEDs the duty cycle of the converter does not change greatly with controlled current. By setting the input voltage of the buck converter to around twice the voltage of diode strings, converter can...

  11. Monte carlo analysis of multicolour LED light engine

    DEFF Research Database (Denmark)

    Chakrabarti, Maumita; Thorseth, Anders; Jepsen, Jørgen

    2015-01-01

    A new Monte Carlo simulation as a tool for analysing colour feedback systems is presented here to analyse the colour uncertainties and achievable stability in a multicolour dynamic LED system. The Monte Carlo analysis presented here is based on an experimental investigation of a multicolour LED...... light engine designed for white tuneable studio lighting. The measured sensitivities to the various factors influencing the colour uncertainty for similar system are incorporated. The method aims to provide uncertainties in the achievable chromaticity coordinates as output over the tuneable range, e...

  12. LED phototherapy system in skin treatment and detecting

    Science.gov (United States)

    Chen, Hsi-Chao; Wu, Jih-Huah; Lin, Ching-Huang; Ma, Shih-Hsin

    2010-08-01

    In this research, a new module of skin treatment has been proposed. The 40 pieces of red and 36 pieces of yellow LEDs are utilized to be the light sources in treatment the cracks and corrosions on skin, and the 4 pieces of white light LEDs are applied in lighting on skin. In addition, the image of skin could be obtained by a CCD webcam, and the skin inspection will be determined by number of pores in images. Finally, the good experimental results have been obtained in human body.

  13. High quality Danish design with intelligent LED light. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Paul Michael; Dam-Hansen, C.; Thestrup, B.; Pedersen, Henrik (Technical Univ. of Denmark, DTU Fotonik, Roskilde (Denmark)); Olsen, Jesper (JesperOlsen ApS, Frederiksberg (Denmark)); Falleboe, H.; Andersen, Jakob (MORFOSO, Copenhagen (Denmark))

    2010-02-15

    Based on the results achieved in a previous project, which enabled a number of designers to be trained in the potential of LED lighting technology, this project developed intelligent LED fixtures for work purposes and for private homes. The two types of fixtures both meet the original project objective of good colour rendition with Ra indices above 90 and colour temperatures variable within the interval 3,300 to 4,400 K. Furthermore, with luminous efficacies of 60 lumen/W, both fixtures have energy efficiencies exceeding that of an average energy-friendly light source. (ln)

  14. Promoting Exercise as Part of a Physiotherapy-Led Falls Pathway Service for Adults with Intellectual Disabilities: A Service Evaluation

    Science.gov (United States)

    Crockett, Jennifer; Finlayson, Janet; Skelton, Dawn A.; Miller, Gillian

    2015-01-01

    Background: People with intellectual disabilities experience high rates of falls. Balance and gait problems are common in people with intellectual disabilities, increasing the likelihood of falls; thus, tailored exercise interventions to improve gait and balance are recommended. The present authors set up a physiotherapy-led falls pathway service…

  15. Vickers Hardness of Composite Resins Cured with LED and QTH Units

    Directory of Open Access Journals (Sweden)

    Alaghemand H

    2016-03-01

    Full Text Available Statement of Problem: One of the factors affecting the degree of polymerization of light-cured composites is the type of light-curing unit used. In addition, physicomechanical properties of the composite resins depend on the degree of conversion and polymerization. Objectives: Since the type of initiator in new composite resins is not explained by manufacturers, this study is an attempt to compare the depth of hardening, with two LED and QTH light-curing units. Materials and Methods: Fifteen samples prepared from Gradia Direct and Filtek Z250, both of which being universal, were cured with QTH (Astralis 7 and LED (Bluephase C8 light-curing units. All the samples were molded in polyester resin and cut from the middle by a disk. The hardness of the cut area was evaluated at 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5 and 4-mm depth intervals and also at the same interval as the width of the sample, with Vickers hardness machine, while the samples were placed in a darkroom. Data were statistically analyzed using one-way ANOVA, two-way ANOVA, t-test and post Hoc Tukey’s tests in SPSS, version 16. Results: Filtek Z250 was harder than Gradia Direct at all the depth with both light-curing units. The hardness of Filtek Z250 sample cured with Astralis 7 was higher than that cured with LED, but with Gradia Direct the LED unit resulted in higher hardness. Curing depth was not significantly different between the groups (p = 0.109. Conclusions: Vickers hardness number for both composites used in this study is in an acceptable range for clinical implications. The composites’ composition is important to be considered for selection of light unit. Based on the findings of the present study, LED did not present more curing depth compared with QTH.

  16. Life-Cycle Assessment of Energy and Environmental Impacts of LED Lighting Products, Part 3: LED Environmental Testing

    Energy Technology Data Exchange (ETDEWEB)

    Tuenge, Jason R.; Hollomon, Brad; Dillon, Heather E.; Snowden-Swan, Lesley J.

    2013-03-01

    This report covers the third part of a larger U.S. Department of Energy (DOE) project to assess the life-cycle environmental and resource impacts in the manufacturing, transport, use, and disposal of light-emitting diode (LED) lighting products in relation to incumbent lighting technologies. All three reports are available on the DOE website (www.ssl.energy.gov/tech_reports.html). • Part 1: Review of the Life-Cycle Energy Consumption of Incandescent, Compact Fluorescent and LED Lamps; • Part 2: LED Manufacturing and Performance; • Part 3: LED Environmental Testing. Parts 1 and 2 were published in February and June 2012, respectively. The Part 1 report included a summary of the life-cycle assessment (LCA) process and methodology, provided a literature review of more than 25 existing LCA studies of various lamp types, and performed a meta-analysis comparing LED lamps with incandescent and compact fluorescent lamps (CFLs). Drawing from the Part 1 findings, Part 2 performed a more detailed assessment of the LED manufacturing process and used these findings to provide a comparative LCA taking into consideration a wider range of environmental impacts. Both reports concluded that the life-cycle environmental impact of a given lamp is dominated by the energy used during lamp operation—the upstream generation of electricity drives the total environmental footprint of the product. However, a more detailed understanding of end-of-life disposal considerations for LED products has become increasingly important as their installation base has grown. The Part 3 study (reported herein) was undertaken to augment the LCA findings with chemical analysis of a variety of LED, CFL, and incandescent lamps using standard testing procedures. A total of 22 samples, representing 11 different models, were tested to determine whether any of 17 elements were present at levels exceeding California or Federal regulatory thresholds for hazardous waste. Key findings include: • The selected

  17. Instructor-led or Learner-led for Elementary Learners to Learn Computer-based Music Composition?

    Directory of Open Access Journals (Sweden)

    Ju-Shih Tseng

    2010-03-01

    Full Text Available The purpose of the present study was to examine the effects of instructional strategy (instructor-led vs. learner-led and grade level (third grade vs. fifth grade on elementary learners’ music composition performance and attitude with the use of a computer-based music composition software. An experimental learning activity was implemented using 5E learning cycle as a pedagogical framework to facilitate learning. A quasi-experimental design was employed with elementary learners participated in the experiment. The results revealed that (a fifth grader outperformed third graders in creativity, whereas third graders were extrinsically motivated and perceived that the computer-based music composition software was useful in learning music composition more than fifth graders were and did; and (b learners with instructor-led instructional strategy outperformed learners with learned-led instructional strategy in creativity and craftsmanship and held high extrinsic motivation than learners with learner-led. The implementations and suggestions for future study were discussed in the present study.

  18. Prostate Problems

    Science.gov (United States)

    ... If you have BPH, you may need to wake up often to urinate when you sleep. If you can’t urinate at all, you should get medical help right away. Your doctor will know if you have a prostate problem based on ...

  19. [Transversal problems].

    Science.gov (United States)

    Mendoza Mendoza, A; Solano Reina, E

    1990-04-01

    In this worn we introduce the alterations of the occlusion in the horizontal level or transversal problems, in which lateral crossed bites appear, either with or without a deviation of the medium line, underlying its differential diagnostic and guide lines treatment through several different clinic cases.

  20. Dewey's Problem.

    Science.gov (United States)

    Cohen, David K.

    1998-01-01

    Maintains that Dewey tried to solve social problems related to the growth of industrialism, increasing economic inequality, and political inequality. Argues that Dewey aspired to create a counterculture to correct the human and social devastation of industrial capitalism through a curriculum and instruction that rooted academic learning in…

  1. Warfarin anticoagulation in hemodialysis patients with atrial fibrillation: comparison of nephrologist-led and anticoagulation clinic-led management.

    Science.gov (United States)

    Bahbahani, Hamad; AlTurki, Ahmed; Dawas, Ahmed; Lipman, Mark L

    2018-01-08

    There is conflicting evidence of benefit versus harm for warfarin anticoagulation in hemodialysis patients with atrial fibrillation. This equipoise may be explained by suboptimal Time in Therapeutic Range (TTR), which correlates well with thromboembolic and bleeding complications. This study aimed to compare nephrologist-led management of warfarin therapy versus that led by specialized anticoagulation clinic. In a retrospective cohort of chronic hemodialysis patients from two institutions (Institution A: Nephrologist-led warfarin management, Institution B: Anticoagulation clinic-led warfarin management), we identified patients with atrial fibrillation who were receiving warfarin for thromboembolic prophylaxis. Mean TTRs, proportion of patients achieving TTR ≥ 60%, and frequency of INR testing were compared using a logistic regression model. In Institution A, 16.7% of hemodialysis patients had atrial fibrillation, of whom 36.8% were on warfarin. In Institution B, 18% of hemodialysis patients had atrial fibrillation, and 55.5% were on warfarin. The mean TTR was 61.8% (SD 14.5) in Institution A, and 60.5% (SD 15.8) in Institution B (p-value 0.95). However, the proportion of patients achieving TTR ≥ 60% was 65% versus 43.3% (Adjusted OR 2.22, CI 0.65-7.63) and mean frequency of INR testing was every 6 days versus every 13.9 days in Institutions A and B respectively. There was no statistical difference in mean TTR between nephrologist-led management of warfarin and that of clinic-led management. However, the former achieved a trend toward a higher proportion of patients with optimal TTR. This improved therapeutic results was associated with more frequent INR monitoring.

  2. LED Light to improve Strawberry Flavour, Quality and Production

    NARCIS (Netherlands)

    Hanenberg, M.A.A.; Janse, J.; Verkerke, W.

    2016-01-01

    A current demonstration in the greenhouses of Wageningen UR in Bleiswijk (the Netherlands) shows positive results of LED light on the quality and production of strawberries (Fragaria x ananassa). In this demonstration two strawberry cultivars, Elsanta and Sonata, are exposed to three different light

  3. Current-voltage model of LED light sources

    DEFF Research Database (Denmark)

    Beczkowski, Szymon; Munk-Nielsen, Stig

    2012-01-01

    Amplitude modulation is rarely used for dimming light-emitting diodes in polychromatic luminaires due to big color shifts caused by varying magnitude of LED driving current and nonlinear relationship between intensity of a diode and driving current. Current-voltage empirical model of light...

  4. A color management system for multi-colored LED lighting

    DEFF Research Database (Denmark)

    Chakrabarti, Maumita; Thorseth, Anders; Jepsen, Jørgen

    2015-01-01

    A new color control system is described and implemented for a five–color LED light engine, covering a wide white gamut. The system combines a new way of using pre-calibrated look-up tables and a rule-based optimization of chromaticity distance from the Planckian locus with a calibrated color sensor...

  5. Effectiveness of a Volunteer-Led Crafts Group Intervention amongst ...

    African Journals Online (AJOL)

    The purpose of this study was to determine the effectiveness of a volunteer led crafts group intervention (VLCG) as an adjunct to antidepressant medication on mild to moderately depressed women. A quasi-experimental, non-equivalent, control group study was conducted in an urban, psychiatric clinic. Depression was ...

  6. Patient safety in midwifery-led care in the Netherlands

    NARCIS (Netherlands)

    Martijn, L.L.M.; Jacobs, A.J.E.; Maassen, I.I.M.; Buitendijk, S.S.E.; Wensing, M.M.

    2013-01-01

    Objective: to describe the incidence and characteristics of patient safety incidents in midwifery-led care for low-risk pregnant women. Design: multi-method study. Setting: 20 midwifery practices in the Netherlands; 1,000 patient records. Population: low-risk pregnant women. Methods: prospective

  7. Nurse-led rehabilitation after gynaecological cancer surgery

    DEFF Research Database (Denmark)

    Seibæk, Lene

    2009-01-01

      Abstract This article presents the preliminary results and experiences from an ongoing study aiming to: Develop and test a nurse-led multidisciplinary rehabilitation programme for women who undergo surgery for localised gynaecological cancers.Evaluate the effect of the programme prospectively o...

  8. Refugee-led humanitarianism in Lebanon’s Shatila camp

    Directory of Open Access Journals (Sweden)

    Hind Sharif

    2018-02-01

    Full Text Available Refugee-led humanitarian initiatives by ‘established’ Palestinian refugees in response to the arrival of ‘new’ displaced Syrians to Shatila camp raise key questions about the limitations of the humanitarian system and representations of refugees as passive victims.

  9. Compact collimators for high brightness blue LEDs using dielectric multilayers

    NARCIS (Netherlands)

    Cornelissen, H.J.; Ma, H.; Ho, C.; Li, M.; Mu, C.

    2011-01-01

    A novel method is presented to inject the light of millimeter-sized high-brightness blue LEDs into light guides of submillimeter thickness. Use is made of an interference filter that is designed to pass only those modes that will propagate in the light guide by total internal reflection. Other modes

  10. High power deep UV-LEDs for analytical optical instrumentation

    Czech Academy of Sciences Publication Activity Database

    Li, Y.; Dvořák, Miloš; Nesterenko, P. N.; Nuchtavorn, N.; Macka, M.

    2018-01-01

    Roč. 255, č. 2 (2018), s. 1238-1243 ISSN 0925-4005 Institutional support: RVO:68081715 Keywords : deep UV Light emitting diodes (LEDs) * optical detection * portable analytical instrumentation Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 5.401, year: 2016

  11. Effect of Laser and LED on Enzymatic Production of Ceramide

    DEFF Research Database (Denmark)

    Hongyu, Zhang; Zhang, Long; Tidemand-Lichtenberg, Peter

    2011-01-01

    using HPTLC (high performance thin-layer chromatography) at 0.5, 1, 2, 3, 4, 6, 17, 24 h after irradiation. The duration of effect was evaluated from the experimental data. The results show that enzyme activity can be increased by using both laser and LED sources whose wavelength is located within...

  12. LED en energiezuinigheid en kwaliteit bij Red Naomi!

    NARCIS (Netherlands)

    Gelder, de Arie; Burg, van der Rick

    2017-01-01

    In order to achieve a signifi cant energy saving, WUR Greenhouse Horticulture and Delphy conducted research under a lighting system with Deep Red / Blue Top- LED. Objectives were consistent growth by uniform light level, improvement of fl ower size and stem weight and 25% saving on electricity. In

  13. Advanced LED package with temperature sensors and microfluidic cooling

    NARCIS (Netherlands)

    Ye, H.; Zeijl, H. van; Sokolovskij, R.; Gielen, A.W.J.; Zhang, G.Q.

    2013-01-01

    Light-emitting diodes (LEDs) are revolutionizing the illumination with energy savings and enhanced functionality. However, around 80% of the input power will be still transferred to heat. As the elevated temperature negatively affects the maximum light output, efficiency, quality, reliability and

  14. Heterostructures for Increased Quantum Efficiency in Nitride LEDs

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Robert F. [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    2010-09-30

    Task 1. Development of an advanced LED simulator useful for the design of efficient nitride-based devices. Simulator will contain graphical interface software that can be used to specify the device structure, the material parameters, the operating conditions and the desired output results. Task 2. Theoretical and experimental investigations regarding the influence on the microstructure, defect concentration, mechanical stress and strain and IQE of controlled changes in the chemistry and process route of deposition of the buffer layer underlying the active region of nitride-based blue- and greenemitting LEDs. Task 3. Theoretical and experimental investigations regarding the influence on the physical properties including polarization and IQE of controlled changes in the geometry, chemistry, defect density, and microstructure of components in the active region of nitride-based blue- and green-emitting LEDs. Task 4. Theoretical and experimental investigations regarding the influence on IQE of novel heterostructure designs to funnel carriers into the active region for enhanced recombination efficiency and elimination of diffusion beyond this region. Task 5. Theoretical and experimental investigations regarding the influence of enhanced p-type doping on the chemical, electrical, and microstructural characteristics of the acceptor-doped layers, the hole injection levels at Ohmic contacts, the specific contact resistivity and the IQE of nitride-based blue- and green-emitting LEDs. Development and optical and electrical characterization of reflective Ohmic contacts to n- and p-type GaN films.

  15. High power deep UV-LEDs for analytical optical instrumentation

    Czech Academy of Sciences Publication Activity Database

    Li, Y.; Dvořák, Miloš; Nesterenko, P. N.; Nuchtavorn, N.; Macka, M.

    Roč. 255, č. 2 ( 2018 ), s. 1238-1243 ISSN 0925-4005 Institutional support: RVO:68081715 Keywords : deep UV Light emitting diodes (LEDs) * optical detection * portable analytical instrumentation Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 5.401, year: 2016

  16. Luminaries-level structure improvement of LEDs for heat dissipation ...

    Indian Academy of Sciences (India)

    Due to its significant advantages such as high efficiency, long lifetime, low power consump- tion, inconceivable controllability and high ... However, till now LED chip can only convert 20% of the input power into light while the rest 80% is converted ... the middle of computational domain. Turbulence natural convection and ...

  17. Underwater Wireless Optical Communication System Using Blue LEDs

    Science.gov (United States)

    Lin, Aobo; Tong, Zheng; Song, Yuhang; Kong, Meiwei; Xu, Jing

    2016-02-01

    We demonstrate a self-designed underwater wireless optical communication system using blue LEDs. The performance of the transmitter and receiver was experimentally investigated. Four different square wave signals (10 KHz, 100 KHz, 500 KHz and 1 MHz) were successfully transmitted via a short water channel at the first phase.

  18. LED light requirements ... for greenhouses and growth rooms

    NARCIS (Netherlands)

    Nederhoff, E.M.

    2011-01-01

    LEDs have potential for use as grow lights in greenhouses to supplement low natural light levels, and also for use in growth rooms and 'plant factories' as the main light source. The light spectrum is critical. Unfortunately, it seems that there is not a simple recipe freely available for growing

  19. Luminaries-level structure improvement of LEDs for heat dissipation ...

    Indian Academy of Sciences (India)

    Furthermore, the natural convection heat transfer process of LED luminaries is simulated by computational fluid dynamics (CFD) model before and after the structural modification. As shown by computational results, boring through-hole is beneficial to develop bottomto-top natural convection, eliminate local circumfluence, ...

  20. EC-LEDS Mexico: Advancing Clean Energy Goals

    Energy Technology Data Exchange (ETDEWEB)

    2016-07-01

    EC-LEDS works with the government of Mexico to help meet its goals of reducing greenhouse gas emissions from the energy sector. The program targets specific, highly technical areas where Mexico has indicated the program can add value and make an impact.

  1. Optical and thermal simulation chain for LED package

    NARCIS (Netherlands)

    Tapaninen, O.; Myohanen, P.; Majanen, M.; Sitomaniemi, A.; Olkkonen, J.; Hildenbrand, V.; Gielen, A.W.J.; Mackenzie, F.V.; Barink, M.; Smilauer, V.; Patzak, B.

    2016-01-01

    This paper presents a test case for coupling two physical aspects of an LED, optical and thermal, using specific simulation models coupled through an open source platform for distributed multi-physics modelling. The glue code for coupling is written with Python programming language including

  2. CALiPER Application Summary Report 15. LED Floodlights

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2012-05-01

    This report analyzes the independently tested performance of 10 LED floodlights purchased between August and December 2011. The group included a wide range of products, both physically and in performance characteristics, which mirrors the nearly indefinite range of conventional luminaires designated as floodlights.

  3. Kattuvad hääled / Reet Varblane

    Index Scriptorium Estoniae

    Varblane, Reet, 1952-

    2008-01-01

    Iisraeli ja palestiina kunstnike näitus "Kattuvad hääled/Overlapping Voices" Essli muuseumis Klosterneuburgis Austrias 16. V-25. X. Kuraatorid: Tal Adler (Iisrael, juut), Amal Murkus (Iisrael, palestiinlane), Karin Schneider ja Friedemann Derschmidt (Austria). Karlheinz ja Agnes Esslile kuuluvast eramuuseumist (1991, arhitekt Heinz Tesar)

  4. Performance of LED fluorescence microscopy for the detection of ...

    African Journals Online (AJOL)

    Introduction: Ziehl-Neelsen (ZN) bright-field microscopy is time-consuming, with poor sensitivity, even under optimal conditions. Introduction of Primo Star iLED fluorescent microscopy (FM) may improve TB case finding at referral hospitals in Rwanda. The study aimed to determine the acceptability and effectiveness of iLED ...

  5. New insights into consumer-led food product development

    NARCIS (Netherlands)

    Costa, A.I.A.; Jongen, W.M.F.

    2006-01-01

    This paper builds upon a review of relevant marketing, consumer science and innovation management literature to introduce the concept of consumer-led new product development and describe its main implementation stages. The potential shortcomings of this concept's application in European food

  6. Biologically inspired LED lens from cuticular nanostructures of firefly lantern

    Science.gov (United States)

    Kim, Jae-Jun; Lee, Youngseop; Kim, Ha Gon; Choi, Ki-Ju; Kweon, Hee-Seok; Park, Seongchong; Jeong, Ki-Hun

    2012-01-01

    Cuticular nanostructures found in insects effectively manage light for light polarization, structural color, or optical index matching within an ultrathin natural scale. These nanostructures are mainly dedicated to manage incoming light and recently inspired many imaging and display applications. A bioluminescent organ, such as a firefly lantern, helps to out-couple light from the body in a highly efficient fashion for delivering strong optical signals in sexual communication. However, the cuticular nanostructures, except the light-producing reactions, have not been well investigated for physical principles and engineering biomimetics. Here we report a unique observation of high-transmission nanostructures on a firefly lantern and its biological inspiration for highly efficient LED illumination. Both numerical and experimental results clearly reveal high transmission through the nanostructures inspired from the lantern cuticle. The nanostructures on an LED lens surface were fabricated by using a large-area nanotemplating and reconfigurable nanomolding with heat-induced shear thinning. The biologically inspired LED lens, distinct from a smooth surface lens, substantially increases light transmission over visible ranges, comparable to conventional antireflection coating. This biological inspiration can offer new opportunities for increasing the light extraction efficiency of high-power LED packages. PMID:23112185

  7. Fluorescent silicon carbide materials for white LEDs and photovoltaics

    DEFF Research Database (Denmark)

    Syväjärvi, Mikael; Ou, Haiyan; Wellmann, Peter

    the luminescence appears in the infrared region in a broad range from 700 to 1100 nm. This potentially can be used to develop an infrared LED for de-icing in wind power and airplanes, or medical applications. Further on, a very efficient solar cell material can be investigated by studying the impurity effect...

  8. Farmer led multiplication of rosette resistant groundnut varieties

    African Journals Online (AJOL)

    Mo

    sure way to provide poor farmers with access to improved varieties, practices, knowledge and information required for ... sustainable, and appropriate, especially for resource poor farmers. In view of this situation this project promotes farmer- led multiplication of rosette resistant Groundnuts varieties .... appropriate solutions.

  9. Bright infrared LEDs based on colloidal quantum-dots

    KAUST Repository

    Sun, Liangfeng

    2013-01-01

    Record-brightness infrared LEDs based on colloidal quantum-dots have been achieved through control of the spacing between adjacent quantum-dots. By tuning the size of quantum-dots, the emission wavelengths can be tuned between 900nm and 1650nm. © 2013 Materials Research Society.

  10. Liquid cooling applications on automotive exterior LED lighting

    Science.gov (United States)

    Aktaş, Mehmet; Şenyüz, Tunç; Şenyıldız, Teoman; Kılıç, Muhsin

    2018-02-01

    In this study cooling of a LED unit with heatsink and liquid cooling block which is used in automotive head lamp applications has been investigated numerically and experimentally. Junction temperature of a LED which is cooled with heatsink and liquid cooling block obtained in the experiment. 23°C is used both in the simulation and the experiment phase. Liquid cooling block material is choosed aluminium (Al) and polyamide. All tests and simulation are performed with three different flow rate. Temperature distribution of the designed product is investigated by doing the numerical simulations with a commercially software. In the simulations, fluid flow is assumed to be steady, incompressible and laminar and 3 dimensional (3D) Navier-Stokes equations are used. According to the calculations it is obtained that junction temperature is higher in the heatsink design compared to block cooled one. By changing the block material, it is desired to investigate the variation on the LED junction temperature. It is found that more efficient cooling can be obtained in block cooling by using less volume and weight. With block cooling lifetime of LED can be increased and flux loss can be decreased with the result of decreased junction temperature.

  11. Assessment of community led total sanitation uptake in rural Kenya

    African Journals Online (AJOL)

    Objective: to assess the magnitude of Community Led total sanitation (CLts) triggering to certification of Open Defecation free (ODF) villages in rural Kenya. Design: A retrospective descriptive study. Setting: the 47 .... Eldoret, Kenya and the Ethics Review Board of. Médecins sans Frontières, Geneva, Switzerland, on.

  12. Multiple Primary LED Lamp Colour Controller with Inherent Brightness Limitation

    NARCIS (Netherlands)

    Barcena, R.; Ackermann, B.

    2007-01-01

    There is a strong interest in using LEDs for general illumination due to the potential they offer for energy saving, environmental friendliness, new opportunities in lighting design, and control of the intensity, colour, and spatial distribution of light. General illumination requires primarily

  13. An unrecognised Adverse Drug Reaction of Enalapril Led to ...

    African Journals Online (AJOL)

    Esem

    An Unrecognised Adverse Drug Reaction of Enalapril. Led to Suspicion of Pulmonary Tuberculosis Infection. 1. 2. 2. 2. 1. Kosamu T., Mwanza K., Mbayo E., Gondwe K. and Besa C. 1School of Medicine, The Copperbelt University, Ndola Campus, Ndola, Zambia. 2 Kitwe Central Hospital, Ministry of Health, Kitwe, Zambia.

  14. Harmonics Study of Common Low Wattage LED Lamps

    Directory of Open Access Journals (Sweden)

    Ioan Dragoş Deaconu

    2017-11-01

    Full Text Available This article presents experimental data on Light Emitting Diode (LED lamps of low wattage that are commonly found both in commercial and residential applications. A comparison with the existing regulations is performed. The measurements are performed using power and energy quality analyzer intended also for avionic and military systems.

  15. Geriatric and Student Perceptions following Student-led Educational Sessions

    Directory of Open Access Journals (Sweden)

    Kristin Janzen

    2018-01-01

    Full Text Available Objective: The objective of this study was to measure the effect of student-led educational events on geriatric patient and student participant perceptions in a community setting. Methods: Students led three events at a senior community center, focusing on learning and memory, sleep hygiene, and arthritis pain. The participants were geriatric patients who themselves were providers of support to homebound peers (“clients” through an independently organized program. Geriatric participants completed pre- and post-event surveys to measure changes in familiarity with the topics. Student participants also completed pre- and post-event surveys that tracked changes in their comfort in working with the geriatric population. Results: Each event demonstrated at least one positive finding for geriatric patients and/or their clients. Students reported increased comfort in working with and teaching the geriatric population following the first and third events, but not the second. Conclusion: Student-led educational sessions can improve perceived health-related knowledge of geriatric participants while simultaneously exposing students to the geriatric patient population. Overall, both students and geriatric participants benefited from these events. Practice Implications: Incorporation of single, student-led educational events could be mutually beneficial to students and the elderly population in the community and easily incorporated into any healthcare curriculum. Funding:This work was supported by a Butler University Innovation Fund Grant. Treatment of Human Subjects: IRB review/approval required and obtained   Type: Original Research

  16. Null bactericidal effect of ultraviolet radiation emitted by LEDs.

    Directory of Open Access Journals (Sweden)

    Francisco Alcántara Muñoz

    2016-11-01

    Full Text Available This research has aimed to assess the bactericidal effect of ultraviolet light emitted by LEDS on the growth on Petri dishes of microorganisms whose legal limits in foods have been established. An electrically fed apparatus has been designed with precise timing and a camera to prevent light spillage, in which two ultraviolet radiation emission devices were connected by LED technology at different wavelengths: through an array of LEDS emitting at around 350nm, and a single specific emission LED at 280nm. 1000 cfu of E. Coli and S. aureus sown on PCA were used as prototypes of gram negative and positive bacteria, respectively, onto which ultraviolet light was radiated at different time intervals, by means of both devices, with the whole experiment being carried out in triplicate . In none of the three series of treatments at the two wavelengths were reductions in microbial growth observed. The series of sowings on PCA were done on unseeded plates in order to be able to discard the likelihood of subsequent recontamination.

  17. Experiencing Child-Led Science in Science Week

    Science.gov (United States)

    Bostrom, Carol

    2016-01-01

    In this article, Carol Bostrom shares how child-led enquiry, with children choosing their own questions to research, can work in a primary classroom. Children in three year 1 classes (ages 5-6) chose three areas of their own interest or hobby and then composed three questions for investigation for each area to be used during science week. This…

  18. LED's in Physics Demos: A Handful of Examples.

    Science.gov (United States)

    Lottis, Dan; Jaeger, Herbert

    1996-01-01

    Describes the use of light-emitting diodes (LED) instead of incandescent bulbs in experiments that generally use battery and bulbs to enable students to explore and understand fundamental electrical phenomena. Presents the following examples: Faraday's Law demonstration, conductors and insulators, and rectifying action of a diode. (JRH)

  19. Thermal simulation and validation of 8W LED lamp

    NARCIS (Netherlands)

    Jakovenko, J.; Werkhoven, R.J.; Formánek, J.; Kunen, J.M.G.; Bolt, P.J.; Kulha, P.

    2011-01-01

    This work deals with thermal simulation and characterization of solid state lightening (SSL) LED Lamp in order to get precise 3D thermal models for further lamp thermal optimization. Simulations are performed with ANSYS-CFX and CoventorWare software tools. The simulated thermal distribution has been

  20. Student-Led Campus Climate Change Initiatives in Canada

    Science.gov (United States)

    Helferty, Anjali; Clarke, Amelia

    2009-01-01

    Purpose: The purpose of this paper is to provide a comprehensive list of student-led, campus-based climate change initiatives, and offers details on many specific cases. The paper also documents the roles students have played and considers the larger youth engagement implications. Many of these initiatives can be replicated elsewhere, thereby…

  1. Patient safety in midwifery-led care in the Netherlands

    NARCIS (Netherlands)

    Martijn, L.M.; Jacobs, A.J.E.; Maassen, II; Buitendijk, S.S.; Wensing, M.J.

    2013-01-01

    OBJECTIVE: to describe the incidence and characteristics of patient safety incidents in midwifery-led care for low-risk pregnant women. DESIGN: multi-method study. SETTING: 20 midwifery practices in the Netherlands; 1,000 patient records. POPULATION: low-risk pregnant women. METHODS: prospective

  2. Cooling of High-Power LED Lamp Using a Commercial Paraffin Wax

    Science.gov (United States)

    Zmywaczyk, J.; Zbińkowski, P.; Smogór, H.; Olejnik, A.; Koniorczyk, P.

    2017-03-01

    Commercial paraffin wax used by Bolsius Nederland B.V. for manufacturing various kinds of candles was applied as a phase-change material (PCM) for cooling a 28 W high-power light emitting diode (LED) panel during its operation. The main problem arising during operation of an LED is thermal management. According to the manufacturer's datasheet specifications (BioSolution Ltd. www.biosolution.pl, the operating temperature range for the LED street lamp UL28W is (-30 {°}C) to (+40 {°}C). The object of the present study was an LED panel containing 28 pieces of high-power 1W LEDs connected in series (4 LEDs in each of the 7 rows) mounted on an aluminum plate of dimensions 80 mm by 135 mm. The tested aluminum plate was placed in a block made of aluminum with a hollow compartment containing Bolsius paraffin wax of density 914 kg\\cdot m^{-3} at room temperature. Temperatures were recorded using K-type thermocouples at selected locations of the tested LED panel for several values of the power supplied to it, while utilizing PCM and without it. As the manufacturer of Bolsius wax candles does not provide any data on the thermal properties of the material used, it was necessary to carry out micro-calorimetric research. Thermophysical properties of the paraffin wax such as the apparent specific heat, enthalpy of phase transition and temperature of phase change transition during heating and cooling were determined using the Netzsch DSC 214 Polyma. The Netzsch TG 209F3 Tarsus was used for TG/DTG measurements. DSC investigations revealed the following thermal transitions taking place during the first heating: solid-solid transition (onset 30.4 {°}C, peak at 40.9 {°}C), solid-liquid transition (onset 47.7 {°}C, peak at 54.9 {°}C, end at 58.3 {°}C), latent heat of energy storage 201 J\\cdot g^{-1}, apparent specific heat corresponding to peak at 41.5 {°}C (5.498 J\\cdot g^{-1}\\cdot K^{-1}). DTG investigations revealed that the decomposition of paraffin wax is a two

  3. Development of an early nurse led intervention to treat children referred to secondary paediatric care with constipation with or without soiling.

    Science.gov (United States)

    Tappin, David; Nawaz, Shazia; McKay, Caroline; MacLaren, Lorraine; Griffiths, Peter; Mohammed, Toby A

    2013-11-20

    Constipation is a common chronic childhood condition referred to secondary care. Effective treatment requires early intervention, prolonged medication to soften stools and behavioural support to achieve a regular habit of sitting on the toilet to pass a stool. The purpose of this audit and service development was to assess routine consultant paediatrician-led care against minimum standards and if appropriate to develop a nurse-led intervention. The new care package could then be tried out within general paediatric clinics in Glasgow as a service evaluation. NICE guideline (CG99) has a research recommendation to compare nurse-led care with routine consultant-led care. Design was an audit then development of a nurse-led intervention followed by a service evaluation. Participants were children (age 0-13 years), referred by their General Practitioner (GP) to the Royal Hospital for Sick Children Glasgow, with constipation the main problem in the GP letter. The audit covered appointment waiting times, intervention provided, initial follow-up and parental satisfaction with routine consultant-led practice. The nurse-led intervention focused on self-help psychology practice with NICE guideline medical support. This was compared with routine consultant paediatrician care in a service evaluation. The audit found consultant-led care had long waiting times, delayed initial follow-up and variable intervention. The new nurse-led intervention is described in detail. The nurse-led intervention performed well compared with consultant-led care. Less 'nurse-led' children, 3/45 (7%), were still constipated passing less than 3 stools per week compared with 8/58 (14%) receiving consultant-led care. Less 'nurse-led' parents, 10/45 (22%), reported their child having pain passing stools in the previous week compared with consultant-led care, 26/58 (45%). The proportion of children, over 4 years, free from soiling accidents was similar, 15/23 (65%) in the nurse-led group and 18/29 (62%) with

  4. Agricultural problems

    International Nuclear Information System (INIS)

    Bickerton, George E.

    1997-01-01

    Although there were not reasons to deplore against major activity release from any of the 110 industrial reactors authorized to operate in US, the nuclear incident that occurred at the Three Mile Island Plant in 1979 urged the public conscience toward the necessity of readiness to cope with events of this type. The personnel of the Emergency Planning Office functioning in the frame of US Department of Agriculture has already participated in around 600 intervention drillings on a federal, local or state scale to plan, test or asses radiological emergency plans or to intervene locally. These exercises allowed acquiring a significant experience in elaborating emergency plans, planning the drillings, working out scenarios and evaluation of the potential impact of accidents from the agricultural point of view. We have also taken part in different international drillings among which the most recent are INEX 1 and RADEX 94. We have found on these occasions that the agricultural problems are essential preoccupations in most of the cases no matter if the context is international, national, local or of state level. The paper poses problems specifically related to milk, fruits and vegetables, soils, meat and meat products. Finally the paper discusses issues like drilling planning, alarm and notification, sampling strategy, access authorizations for farmers, removing of contamination wastes. A number of social, political and economical relating problems are also mentioned

  5. How applicable is export-led growth and import-led growth hypotheses to South African economy? The VECM and causality approach

    Directory of Open Access Journals (Sweden)

    Ntebogang Dinah Moroke

    2015-04-01

    Full Text Available This paper investigated exports, imports and the economic growth nexus in the context of South Africa. The paper sets out to examine if long-run and causal relationships exist between these variables. Quarterly time series data ranging between 1998 and 2013 obtained from the South African Reserve Bank and Quantec databases was employed. Initial data analysis proved that the variables are integrated at their levels. The results further indicated that exports, imports and economic growth are co-integrated, confirming an existence of a long-run equilibrium relationship. Granger causal results were shown running from exports and imports to GDP and from imports to exports, validating export-led and import-led growth hypotheses in South Africa. A significant causality running from imports to exports, suggests that South Africa imported finished goods in excess. If this is not avoided, lots of problems could be caused. A suggestion was made to avoid such problematic issues as they may lead to replaced domestic output and displacement of employees. Another dreadful ramification may be an adverse effect on the economy which may further be experienced in the long-run

  6. Conduction-driven cooling of LED-based automotive LED lighting systems for abating local hot spots

    Science.gov (United States)

    Saati, Ferina; Arik, Mehmet

    2018-02-01

    Light-emitting diode (LED)-based automotive lighting systems pose unique challenges, such as dual-side packaging (front side for LEDs and back side for driver electronics circuit), size, harsh ambient, and cooling. Packaging for automotive lighting applications combining the advanced printed circuit board (PCB) technology with a multifunctional LED-based board is investigated with a focus on the effect of thermal conduction-based cooling for hot spot abatement. A baseline study with a flame retardant 4 technology, commonly known as FR4 PCB, is first compared with a metal-core PCB technology, both experimentally and computationally. The double-sided advanced PCB that houses both electronics and LEDs is then investigated computationally and experimentally compared with the baseline FR4 PCB. Computational models are first developed with a commercial computational fluid dynamics software and are followed by an advanced PCB technology based on embedded heat pipes, which is computationally and experimentally studied. Then, attention is turned to studying different heat pipe orientations and heat pipe placements on the board. Results show that conventional FR4-based light engines experience local hot spots (ΔT>50°C) while advanced PCB technology based on heat pipes and thermal spreaders eliminates these local hot spots (ΔT<10°C), leading to a higher lumen extraction with improved reliability. Finally, possible design options are presented with embedded heat pipe structures that further improve the PCB performance.

  7. From the Provider-Led to an Employer-Led System: Implications of Apprenticeship Reform on the Private Training Market

    Science.gov (United States)

    Chankseliani, Maia; Relly, Susan James

    2015-01-01

    Despite expending a great deal of public money, and after many government-led "reforms" to develop an apprenticeship system that rivals those found in other countries, the apprenticeship system in England still faces a number of challenges and failings, not least in the private training market. This paper explores the landscape of…

  8. Finding Urban Identity through Culture-led Urban Regeneration

    Directory of Open Access Journals (Sweden)

    Kyu Hong Hwang

    Full Text Available ABSTRACT: A city experiencing a cycle from growth to decline cannot maintain sustainable development without the type of urban identity that could be consolidated by culture-led urban regeneration. A plan for urban regeneration in a declining urban area should be practiced partially or on the whole according to the characteristics of the community. By transforming a low-value and deteriorated area into a highly valued district, the local community can simultaneously restore its social pride, revive the local economy, and realize an urban identity.Firstly, this paper examines urban decline in order to better understand urban regeneration and the need for multidisciplinary management, and also, by considering the necessity for and universal types of urban regeneration, investigates the characteristics of culture-led urban regeneration as a tool for realizing socio-economic revival and urban identity. In particular, this study suggests the action techniques and benchmarking points for urban regeneration by analyzing cases of culture-led urban regeneration in Korea. Three subjects were considered as case studies in this paper: 1 Hanok village in Jeonju city, which changed from a twilight zone to a tourist attraction; 2 Changdong district in Changwon city, which recovered from an area of declining and dark alleyways that had been the hub for arts and culture in the 1970s to become a new artist village; and 3 Cheongju city, which is being transformed from an idle industrial facility into a cultural space. This thesis suggests the implementation process of culture-led urban regeneration to find an urban identity through analysis of the causes of urban decline, the methods of regeneration, and the results of urban regeneration in the three aforementioned cases. In the conclusion section of this paper, the implementation process for culture-led urban regeneration is summarized as consisting of 5 phases: Phase 1, the diagnosis of decline; Phase 2

  9. County of Hawaii - A Unique LED Street Light Conversion

    Science.gov (United States)

    Thiel, Ronald LeRoy

    2015-08-01

    In 2010 the County of Hawaii was paying $0.40/kW-Hr for electricity, $1.5 mil annual bill for 8,500 street lights. Over the past 20 years costs have increased on an average of 7% per year. Inventory maintenance frequency for the 8,500 lights was 35%, which meant 3,000 visits per year. The current LPS street lights were nearing 20 years of service and a complete replacement was imminent, a significant cost for the County of Hawaii and its 185,000 citizens.The astronomy community impact was identified early on and discussions conducted for an acceptable conversion path. Key concerns centered on the blue light content of the LED and reflected light.A demo project with Federal ARRA funds installed 1,000 LED full cut off fixtures achieving an energy savings of $200K annually. The results were extremely successful and were loudly applauded by both the general public and the Astronomy Institute. Hence, the Traffic Division recommended to the County administration changing the remaining lights, now numbering 9,000, to new LED lights. The County administration approved the change to the LED lights and an upgrade to the outdoor lighting ordinance.The remainder of the conversion, amounting to $6 million for materials and labor, is expected to yield an energy savings of approximately $800K annually with a 5 year recovery of costs that includes both energy savings and maintenance reduction.Additional benefits achieved from using full cutoff fixtures include reduction in glare for drivers, pedestrians, and elimination of trespass light onto neighboring residences.Benefits achieved by using a filtered LED includes reducing blue light to <1 %, diffusing the harshness of the direct LED light and the ability to use the most energy efficient lumen producing fixture to achieve in excess of 63% reduction in energy costs.Additional aspects of this conversion presentation will include steps to gather quantitative data showing reduction in light pollution, aerial and satellite surveys for

  10. Design of Elliptic Reflective LED Surgical Shadowless Lamps Using Mathematical Optical Tracing Algorithms

    Directory of Open Access Journals (Sweden)

    Cheng-Tang Pan

    2014-01-01

    Full Text Available Traditional surgical shadowless halogen lamps are generally designed as projection type with many light bulbs, which can produce not only mercury pollution but also heat radiation that are serious problems to patient. The study utilized Runge-Kutta methods and mathematical algorithms to design and optimize the freeform lens. The LED (light-emitting diode was adopted to replace the traditional halogen lamp. A uniform lens was designed and fabricated based on the energy conservation. At first, the light field of LED is concentrated through the freeform lens to improve the optical efficiency. Second, the three-shell elliptic curves are applied to the reflective surgical shadowless lamps, where only few LED chips are needed. Light rays emitting from different directions to the target plane can achieve the goal of shadowless. In this study, the LED’s luminance flux is 1,895 lm. The shadow dilution on the target plane is 54%. Ec (central illuminance is 114,900 lux, and the d50/d10 is 57% which is higher than the regulation by 7%, whereas the power consumption is only 20 W. The energy of reflective surgical shadowless lamps can save more than 50%, compared with the traditional projective one.

  11. Problem: Heart Valve Stenosis

    Science.gov (United States)

    ... Understanding Problems and Causes Heart Murmurs and Valve Disease "Innocent" Heart Murmur Problem: Valve Stenosis - Problem: Aortic Valve Stenosis - Problem: Mitral Valve Stenosis - Problem: Tricuspid Valve Stenosis - Problem: Pulmonary Valve Stenosis Problem: Mitral ...

  12. A self-calibrating led-based solar test platform

    DEFF Research Database (Denmark)

    Krebs, Frederik C; Sylvester-Hvid, Kristian O.; Jørgensen, Mikkel

    2011-01-01

    A compact platform for testing solar cells is presented. The light source comprises a multi-wavelength high-power LED (light emitting diode) array allowing the homogenous illumination of small laboratory solar cell devices (substrate size 50 × 25 mm) within the 390–940 nm wavelength range......, it is possible to perform all the commonly employed measurements on the solar cell at very high speed without moving the sample. In particular, the LED-based illumination system provides an alternative to light-biased incident photon-to-current efficiency measurement to be performed which we demonstrate. Both...... top and bottom contact is possible and the atmosphere can be controlled around the sample during measurements. The setup was developed for the field of polymer and organic solar cells with particular emphasis on enabling different laboratories to perform measurements in the same manner and obtain...

  13. Universal fixture design for body mounted LED lights

    Science.gov (United States)

    Hajra, Debdyut

    2017-09-01

    Today LED headlamps, armbands and ankle-bands, shoe-lights etc. have become very popular. These find extensive use in search and rescue operations, mining, carving, etc. and are also used by individuals during hiking, trekking, running, etc. during dark hours. They serve two main purposes: they provide sufficient illumination in low light conditions and they are used to indicate the presence of a person after dark. These have the same basic requirements. They must produce sufficient light, have high durability, long battery life, must be light weight and energy efficient. This paper discusses possibilities of designing a universal LED fixture can be designed so that it meets the respective needs of everyone irrespective of their background and industry. It discusses the materials to be used for its different body parts, innovative clip design for attachment with support structures like head and armbands, helmets, shoes, etc.

  14. A fast template matching method for LED chip Localization

    Directory of Open Access Journals (Sweden)

    Zhong Fuqiang

    2015-01-01

    Full Text Available Efficiency determines the profits of the semiconductor producers. So the producers spare no effort to enhance the efficiency of every procedure. The purpose of the paper is to present a method to shorten the time to locate the LED chips on wafer. The method consists of 3 steps. Firstly, image segmentation and blob analyzation are used to predict the positions of potential chips. Then predict the orientations of potential chips based on their dominant orientations. Finally, according to the positions and orientations predicted above, locate the chips precisely based on gradient orientation features. Experiments show that the algorithm is faster than the traditional method we choose to locate the LED chips. Besides, even the orientations of the chips on wafer are of big deviation to the orientation of the template, the efficiency of this method won't be affected.

  15. Future Solid State Lighting using LEDs and Diode Lasers

    DEFF Research Database (Denmark)

    Petersen, Paul Michael

    2014-01-01

    significant savings. Solid state lighting (SSL) based on LEDs is today the most efficient light source for generation of high quality white light. Diode lasers, however, have the potential of being more efficient than LEDs for the generation of white light. A major advantage using diode lasers for solid state......Lighting accounts for 20% of all electrical energy usage. Household lighting and commercial lighting such as public and street lighting are responsible for significant greenhouse gas emissions. Therefore, currently many research initiatives focus on the development of new light sources which shows...... lighting is that the high efficiency can be obtained at high light lumen levels in a single element emitter and thus less light sources are required to achieve a desired light level. Furthermore, the high directionality of the generated light from laser diodes increases the energy savings in many...

  16. High-power UV-B LEDs with long lifetime

    Science.gov (United States)

    Rass, Jens; Kolbe, Tim; Lobo-Ploch, Neysha; Wernicke, Tim; Mehnke, Frank; Kuhn, Christian; Enslin, Johannes; Guttmann, Martin; Reich, Christoph; Mogilatenko, Anna; Glaab, Johannes; Stoelmacker, Christoph; Lapeyrade, Mickael; Einfeldt, Sven; Weyers, Markus; Kneissl, Michael

    2015-03-01

    UV light emitters in the UV-B spectral range between 280 nm and 320 nm are of great interest for applications such as phototherapy, gas sensing, plant growth lighting, and UV curing. In this paper we present high power UV-B LEDs grown by MOVPE on sapphire substrates. By optimizing the heterostructure design, growth parameters and processing technologies, significant progress was achieved with respect to internal efficiency, injection efficiency and light extraction. LED chips emitting at 310 nm with maximum output powers of up to 18 mW have been realized. Lifetime measurements show approximately 20% decrease in emission power after 1,000 operating hours at 100 mA and 5 mW output power and less than 30% after 3,500 hours of operation, thus indicating an L50 lifetime beyond 10,000 hours.

  17. Creativity and Impact of Advertising Electronic Led Billboards in Jakarta

    Directory of Open Access Journals (Sweden)

    Suprayitno Suprayitno

    2016-04-01

    Full Text Available The creativity and the impact of advertising electronic LED billboards in Jakarta was an approach to see, to know and to understand in a deeper way. Creativity decisions affect all advertising, art, and knowledge combined with the phrase creative strategy. Creative advertising ideas must be original, unique, different, new, unexpected and right on target. The approach used was qualitative research methods, including data collection in the form of literature review, interviews with the actors and the surrounding communities, as well as documenting the billboard directly outside the media was located. The results of this research are the analysis report the creativity and impact of LED electronic billboard advertising effectiveness, is expected to produce a more detailed picture. So that students and practitioners can use the visual communication design, process, and maximize the advertising rules in designing a design to reach the stage of design creativity and better application. 

  18. High-performance LED luminaire for sports hall

    Science.gov (United States)

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

    2015-09-01

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

  19. Photometric characterization of LED's for optimal design of interior lamps

    International Nuclear Information System (INIS)

    Hernandez, O.; Guerra, H.; Leon, V.; Torres, A. W.; Castannon, H.; Camas, J.

    2012-01-01

    The Tuxtla Gutierrez Technology Institute, and the Innovaluz of Mexico S A of C V company have joined forces to develop LED lighting technology in Chiapas, Mexico. We performed a comprehensive study of power savings for a household using this luminary. The main results of the Lighting are presented exclusively for the ILIGPL153BF24W model, as well as the design features of a functional lamp. (Author)

  20. Body temperature changes of newborns under fluorescent versus LED phototherapy.

    Science.gov (United States)

    Aydemir, Ozge; Soysaldı, Emel; Kale, Yusuf; Kavurt, Sumru; Bas, Ahmet Yagmur; Demirel, Nihal

    2014-08-01

    To determine changes in body temperature (BT) of hyperbilirubinemic newborns under conventional phototherapy with fluorescent lamps and light emitting diodes (LED) at different irradiances. Otherwise healthy newborn infants >34 wk gestational age (GA) hospitalized for indirect hyperbilirubinemia, requiring phototherapy in the first 10 d of life were enrolled. Infants who received conventional phototherapy with fluorescent lamps (10-15 μW/cm(2)/nm irradiance) were defined as group 1, LED phototherapy of 26-60 μW/cm(2)/nm irradiance as group 2, and LED phototherapy of 60-120 μW/cm(2)/nm irradiance as group 3. Primary outcome measure was mean BT which was defined as arithmetical mean of axillary BT measured at 2 h intervals during the first day of phototherapy. Thirty patients were enroled in each group. Mean birth weight and GA of the total cohort was 2800 ± 530 g and 36.6 ± 2 wk, respectively. Baseline demographic variables and serum total bilirubin levels were similar among groups. Mean BT was 36.7 ± 0.1 °C in group 1, 36.6 ± 0.2 °C in group 2, 37.7 ± 0.2 °C in group 3. Mean BT was higher in group 3 compared to group 1 (p phototherapy all the patients in group 3 had at least one BT measurement ≥ 37.5 °C and 77 % had BT ≥ 38 °C. Only one patient in group 2 had BT ≥ 37.5 °C which was also ≥ 38 °C. During phototherapy all BT measurements were LED phototherapy of ≥ 60 μW/cm(2)/nm intensity significantly increases BT in hyperbilirubinemic newborns.

  1. Measuring progress towards a primary care-led NHS.

    Science.gov (United States)

    Miller, P; Craig, N; Scott, A; Walker, A; Hanlon, P

    1999-07-01

    The push towards a 'primary care-led' National Health Service (NHS) has far-reaching implications for the future structure of the NHS. The policy involves both a growing emphasis on the role of primary care practitioners in the commissioning of health services, and a change from hospital to primary and community settings for a range of services and procedures. Although the terminology has changed, this emphasis remains in the recent Scottish Health Service White Paper and its English counterpart. To consider three questions in relation to this policy goal. First, does the evidence base support the changes? Secondly, what is the scale of the changes that have occurred? Thirdly, what are the barriers to the development of a primary care-led NHS? Programme budgets were compiled to assess changes over time in the balance of NHS resource allocation with respect to primary and secondary care. Total NHS revenue expenditure for the 15 Scottish health boards was grouped into four blocks or 'programmes': primary care, secondary care, community services, and a residual. The study period was 1991/2 to 1995/6. Expenditure data were supplied by the Scottish Office. Ambiguity of definitions and the absence of good data cause methodological difficulties in evaluating the scale and the appropriateness of the shift. The data that are available suggest that, at the aggregate level, there have been changes over time in the balance of resource allocation between care settings: relative investment into primary care has increased. It would appear that this investment is relatively small and from growth money rather than a 'shift' from secondary care. In addition, the impact of GP-led commissioning is variable but limited. General practitioners' (GPs') attitudes to the policy suggest that progress towards a primary care-led NHS will continue to be patchy. The limited shift to date, alongside evidence of ambivalent attitudes to the shift on the part of GPs, suggest that this is a policy

  2. Demonstration Assessment of LED Roadway Lighting: Philadelphia, PA

    Energy Technology Data Exchange (ETDEWEB)

    Royer, Michael P.; Tuenge, Jason R.; Poplawski, Michael E.

    2012-09-01

    For this demonstration assessment, 10 different groups of LED luminaires were installed at three sites in Philadelphia, PA. Each of the three sites represented a different set of conditions, most importantly with regard to the incumbent HPS luminaires, which were nominally 100 W, 150 W, and 250 W. The performance of each product was evaluated based on manufacturer data, illuminance calculations, field measurements of illuminance, and the subjective impressions of both regular and expert observers.

  3. Demonstration of LED Street Lighting in Kansas City, MO

    Energy Technology Data Exchange (ETDEWEB)

    Kinzey, Bruce R.; Royer, Michael P.; Hadjian, M.; Kauffman, Rick

    2013-06-10

    Nine different streetlighting products were installed on various streets in Kansas City, Missouri during February, 2011, to evaluate their performance relative to the incumbent high-pressure sodium (HPS) lighting. The applications investigated included 100 W, 150 W, 250 W, and 400 W HPS installations. Initial measurements and comparisons included power, illuminance, and luminance; sample illuminance readings have continued at each of the nine locations at roughly 1,000-hour operating intervals since then. All of the LED products consumed less power than their HPS counterparts—with a mean difference of 39% and a range of 31% to 51%—but they also emitted 31% fewer lumens, on average. The net result is just a 15% increase in mean efficacy. Applying the city’s stringent light loss factors to the initial measured data meant that five of the LED products (and two of the HPS luminaires) were predicted to eventually fail to meet the specified mean illuminance over their lifetimes; however, the specified light loss levels are not expected to be reached by the LED products until some distant future date (between 12 and 30 years after installation according to manufacturer specification sheet estimates). The practical value of designing streetlighting systems to meet illumination requirements more than 15 years in the future is questioned. Numerous sources of variation in field measurements are noted throughout the report, particularly seasonal influences such as ambient temperature and foliage that are evident in the time-series illuminance data.

  4. Application of high-brightness LEDs in aircraft position lights

    Science.gov (United States)

    Machi, Nicolo; Mangum, Scott; Singer, Jeffrey M.

    2004-10-01

    Solid state lighting devices have made their way into a number of niche markets and continue to make inroads into other markets as their price / performance ratios improve. One of these markets is aviation lighting. Although this paper will focus on the use of LEDs for aircraft position lights, much of the discussion is applicable to other installations on the interior and exterior of the aircraft. The color, light distribution and intensity levels for a position light are all closely regulated through Code of Federal Regulation (CFR; formerly Federal Aviation Regulation (FAR)) documents. These lighting requirements, along with harsh thermal and environmental requirements, drive the design. In this paper, we will look at these requirements and discuss what is required in order to use LEDs for this type of application. We will explore the optical, thermal and electrical issues associated with the use of LEDs for position lights and examine the specific case study of the Astreon forward position lights. Finally, we will discuss some of the challenges that we see with solid state lighting in current and future aircraft applications.

  5. High Efficacy Green LEDs by Polarization Controlled MOVPE

    Energy Technology Data Exchange (ETDEWEB)

    Wetzel, Christian [Rensselaer Polytechnic Inst., Troy, NY (United States)

    2013-03-31

    Amazing performance in GaInN/GaN based LEDs has become possible by advanced epitaxial growth on a wide variety of substrates over the last decade. An immediate push towards product development and worldwide competition for market share have effectively reduced production cost and generated substantial primary energy savings on a worldwide scale. At all times of the development, this economic pressure forced very fundamental decisions that would shape huge industrial investment. One of those major aspects is the choice of epitaxial growth substrate. The natural questions are to what extend a decision for a certain substrate will limit the ultimate performance and to what extent, the choice of a currently more expensive substrate such as native GaN could overcome any of the remaining performance limitations. Therefore, this project has set out to explore what performance characteristic could be achieved under the utilization of bulk GaN substrate. Our work was guided by the hypotheses that line defects such as threading dislocations in the active region should be avoided and the huge piezoelectric polarization needs to be attenuated – if not turned off – for higher performing LEDs, particularly in the longer wavelength green and deep green portions of the visible spectrum. At their relatively lower performance level, deep green LEDs are a stronger indicator of relative performance improvements and seem particular sensitive to the challenges at hand.

  6. Evaluation of a nurse-led haemophilia counselling service.

    LENUS (Irish Health Repository)

    O'Shea, Eadaoln

    2012-01-01

    Genetic counselling and testing for females with a family history of haemophilia has long been advocated. However, there is little research in regard to clients\\' satisfaction with the existing counselling models in haemophilia, and in particular with nurse-led clinics. The purpose of this study was to evaluate whether clients were satisfied with a nurse-led carrier testing clinic and counselling service. A retrospective quantitative study of clients\\' satisfaction and perceived knowledge was undertaken using an anonymous questionnaire. A sample of 42 women who had attended the clinic in the last 12 months was identified. The response rate for the study was 71% (n = 30).Two thirds of the respondents were 35 years of age or younger, 93% had a family history of haemophilia and 56% were diagnosed as carriers. Perceived understanding and knowledge increased significantly between the first and second appointments (p < 0.001). Overall, the study identified a high level of client satisfaction with the nurse-led carrier testing clinic and counselling service.

  7. Monolayer graphene dispersion and radiative cooling for high power LED

    Science.gov (United States)

    Hsiao, Tun-Jen; Eyassu, Tsehaye; Henderson, Kimberly; Kim, Taesam; Lin, Chhiu-Tsu

    2013-10-01

    Molecular fan, a radiative cooling by thin film, has been developed and its application for compact electronic devices has been evaluated. The enhanced surface emissivity and heat dissipation efficiency of the molecular fan coating are shown to correlate with the quantization of lattice modes in active nanomaterials. The highly quantized G and 2D bands in graphene are achieved by our dispersion technique, and then incorporated in an organic-inorganic acrylate emulsion to form a coating assembly on heat sinks (for LED and CPU). This water-based dielectric layer coating has been formulated and applied on metal core printed circuit boards. The heat dissipation efficiency and breakdown voltage are evaluated by a temperature-monitoring system and a high-voltage breakdown tester. The molecular fan coating on heat dissipation units is able to decrease the equilibrium junction temperature by 29.1 ° C, while functioning as a dielectric layer with a high breakdown voltage (>5 kV). The heat dissipation performance of the molecular fan coating applied on LED devices shows that the coated 50 W LED gives an enhanced cooling of 20% at constant light brightness. The schematics of monolayer graphene dispersion, undispersed graphene platelet, and continuous graphene sheet are illustrated and discussed to explain the mechanisms of radiative cooling, radiative/non-radiative, and non-radiative heat re-accumulation.

  8. LED-Based High-Voltage Lines Warning System

    Directory of Open Access Journals (Sweden)

    Eldar MUSA

    2013-04-01

    Full Text Available LED-based system, running with the current of high-voltage lines and converting the current flowing through the line into the light by using a toroid transformer, has been developed. The transformer’s primary winding is constituted by the high voltage power line. Toroidal core consists of two equal parts and the secondary windings are evenly placed on these two parts. The system is mounted on the high-voltage lines as a clamp. The secondary winding ends are connected in series by the connector on the clamp. LEDs are supplied by the voltage at the ends of secondary. Current flowing through highvoltage transmission lines is converted to voltage by the toroidal transformer and the light emitting LEDs are supplied with this voltage. The theory of the conversion of the current flowing through the line into the light is given. The system, running with the current of the line and converting the current into the light, has been developed. System has many application areas such as warning high voltage lines (warning winches to not hinder the high-voltage lines when working under the lines, warning planes to not touch the high-voltage lines, remote measurement of high-voltage line currents, and local illumination of the line area

  9. In-vivo wound healing modulation after irradiation with a blue LED photocoagulator

    Science.gov (United States)

    Rossi, Francesca; Cicchi, Riccardo; Magni, Giada; Tatini, Francesca; Bacci, Stefano; Paroli, Gaia; Alfieri, Domenico; Tripodi, Cristina; De Siena, Gaetano; Pavone, Francesco S.; Pini, Roberto

    2017-07-01

    A faster healing process was observed in superficial skin wounds after irradiation with a blue LED (EmoLED) photocoagulator. EmoLED is a compact handheld device, used to induce a thermal effect and thus coagulation in superficial abrasions. We present the results of an in vivo study, conducted in different mouse model, to analyze the induced wound healing. Two superficial abrasions were produced on the back of the mice: one area was treated with EmoLED (1.4 W/cm2, 30 s treatment time), while the other one was left naturally recovering. During the treatment, a temperature around 40-45°C was induced on the abrasion surface. Mice back healthy skin was used as a control. We compared the treatment in black mice, healthy albino mice, diabetic albino mice and albino mice with coagulation problem. The animals underwent a follow up study and were sacrificed at 0, 3, 6, 9, 18, 24 hours p.o.. Samples from the two abraded areas were harvested and examined by histopathological and immunofluorescence analysis, SHG imaging and confocal microscopy. The aim of the study was to compare the effects in the different target groups and to investigate the early phase of the wound healing process. Our results show that the effects are comparable in all the treated groups and that the healing process appears to be faster in respect to the naturally recovered wounds. This study confirms the previous results obtained in a study on a rat model an in a study on healthy albino mice: the selective photothermal effect we used for inducing immediate coagulation in superficial wounds seems to be associated to a faster and improved healing process.

  10. Community Peer-Led Falls Prevention Presentations: What Do the Experts Suggest?

    Science.gov (United States)

    Khong, Linda A M; Berlach, Richard G; Hill, Keith D; Hill, Anne-Marie

    2018-04-01

    Falls among older adults are a major problem. Despite considerable progress in falls prevention research, older adults often show low motivation to engage in recommended preventive strategies. Peer-led falls prevention education for older adults may have potential for bridging the research evidence-practice gap, thereby promoting the uptake of falls prevention strategies. We evaluated peer educators' presentations of falls prevention education to community-dwelling older adults in regard to established criteria that were consistent with adult learning principles, the framework of health behaviour change, falls prevention guidelines, and recommendations for providing falls prevention information. We conducted a within-stage mixed model study using purposive and snowball sampling techniques to recruit 10 experts to evaluate video recordings of the delivery of three peer-led falls prevention presentations. Each expert viewed three videos and rated them using a questionnaire containing both open-ended and closed items. There was a good level of expert agreement across the questionnaire domains. Though the experts rated some aspects of the presentations highly, they thought that the presentations were mainly didactic in delivery, not consistently personally relevant to the older adult audience, and did not encourage older adults to engage in the preventive strategies that were presented. Based on the experts' findings, we developed five key themes and recommendations for the effective delivery of peer-led falls prevention presentations. These included recommending that peer educators share falls prevention messages in a more interactive and experiential manner and that uptake of strategies should be facilitated by encouraging the older adults to develop a personalised action plan. Findings suggest that if peer-led falls prevention presentations capitalise on older adults' capability, opportunity, and motivation, the older adults may be more receptive to take up falls

  11. A novel LED-based device for occlusal caries detection.

    Science.gov (United States)

    Aktan, Ali Murat; Cebe, Mehmet Ata; Ciftçi, Mehmet Ertuğrul; Sirin Karaarslan, Emine

    2012-11-01

    The aim of this in-vitro study was to compare the performance of laser-based (DIAGNOdent, KaVo, Biberach, Germany) and LED-based (Midwest Caries I.D., DENTSPLY Professional, New York, USA) caries detectors in the detection of occlusal caries in permanent molars. The study consisted of 129 visually sound or non-cavitated pits or fissures in 82 extracted permanent human molar teeth. Two trained examiners used the laser-based and LED-based caries detectors to examine the fissures for caries. The teeth were then sectioned at the surfaces suspected of containing occlusal caries and histologically evaluated using stereomicroscopy as a gold standard. Inter-examiner reliability of the caries detector examination was assessed using Cohen's Kappa statistics. The sensitivity, specificity, and accuracy in diagnosing occlusal caries using the two devices were calculated according to appropriate cut-off scores. Receiver operating characteristic (ROC) curves were also determined to compare the diagnostic performance of the devices in occlusal caries diagnosis. The cut-off level of significance was taken as p = 0.005. Cohen's Kappa showed substantial agreement for the laser-based caries detector (0.74), and almost perfect agreement for the LED-based (0.89) caries detector. The specificity of the laser-based device varied from 0.49 to 0.97 at T1 and T2. Its sensitivity varied from 0.33 to 0.65 at T1 and T2. The specificity of the LED-based device varied from 0.48 to 0.56 at T1 and T2. Its sensitivity varied from 0.65 to 0.84 at T1 and from 0.80 to 0.84 at T2. Taking the limitations of the current study into consideration, the DIAGNOdent laser pen was more accurate in determining when teeth were free of occlusal caries than was the Midwest Caries I.D. LED-based device, although the Midwest Caries I.D. device more often revealed the presence of occlusal caries than did the DIAGNOdent pen.

  12. Application Summary Report 22: LED MR16 Lamps

    Energy Technology Data Exchange (ETDEWEB)

    Royer, Michael P.

    2014-07-23

    This report analyzes the independently tested photometric performance of 27 LED MR16 lamps. It describes initial performance based on light output, efficacy, distribution, color quality, electrical characteristics, and form factor, with comparisons to a selection of benchmark halogen MR16s and ENERGY STAR qualification thresholds. Three types of products were targeted. First, CALiPER sought 3000 K lamps with the highest rated lumen output (i.e., at least 500 lm) or a claim of equivalency to a 50 W halogen MR16 or higher. The test results indicate that while the initial performance of LED MR16s has improved across the board, market-available products still do not produce the lumen output and center beam intensity of typical 50 W halogen MR16 lamps. In fact, most of the 18 lamps in this category had lower lumen output and center beam intensity than a typical 35 W halogen MR16 lamp. Second, CALiPER sought lamps with a CRI of 90 or greater. Only four manufacturers were identified with a product in this category. CALiPER testing confirmed the performance of these lamps, which are a good option for applications where high color fidelity is needed. A vast majority of the LED MR16 lamps have a CRI in the low 80s; this is generally acceptable for ambient lighting, but may not always be acceptable for focal lighting. For typical LED packages, there is a fundamental tradeoff between CRI and efficacy, but the lamps in the high-CRI group in this report still offer comparable performance to the rest of the Series 22 products in other performance areas. Finally, CALiPER sought lamps with a narrow distribution, denoted as a beam angle less than 15°. Five such lamps were purchased. Notably, no lamp was identified as having high lumen output (500 lumens or greater), high CRI (90 or greater), a narrow distribution (15° or less), and an efficacy greater than 60 lm/W. This would be an important achievement for LED MR16s especially if output could reach approximately 700 800 lumens

  13. EDITORIAL: Micro-pixellated LEDs for science and instrumentation

    Science.gov (United States)

    Dawson, Martin D.; Neil, Mark A. A.

    2008-05-01

    This Cluster Issue of Journal of Physics D: Applied Physics highlights micro-pixellated gallium nitride light-emitting diodes or `micro-LEDs', an emerging technology offering considerable attractions for a broad range of scientific and instrumentation applications. It showcases the results of a Research Councils UK (RCUK) Basic Technology Research programme (http://bt-onethousand.photonics.ac.uk), running from 2004-2008, which has drawn together a multi-disciplinary and multi-institutional research partnership to develop these devices and explore their potential. Images of LEDs Examples of GaN micro-pixel LEDs in operation. Images supplied courtesy of the Guest Editors. The partnership, of physicists, engineers and chemists drawn from the University of Strathclyde, Heriot-Watt University, the University of Sheffield and Imperial College London, has sought to move beyond the established mass-market uses of gallium nitride LEDs in illumination and lighting. Instead, it focuses on specialised solid-state micro-projection devices the size of a match-head, containing up to several thousand individually-addressable micro-pixel elements emitting light in the ultraviolet or visible regions of the spectrum. Such sources are pattern-programmable under computer control and can project into materials fixed or high-frame rate optical images or spatially-controllable patterns of nanosecond excitation pulses. These materials can be as diverse as biological cells and tissues, biopolymers, photoresists and organic semiconductors, leading to new developments in optical microscopy, bio-sensing and chemical sensing, mask-free lithography and direct writing, and organic electronics. Particular areas of interest are multi-modal microscopy, integrated forms of organic semiconductor lasers, lab-on-a-chip, GaN/Si optoelectronics and hybrid inorganic/organic semiconductor structures. This Cluster Issue contains four invited papers and ten contributed papers. The invited papers serve to set

  14. Directed self-assembly of mesoscopic components for led applications

    Science.gov (United States)

    Tkachenko, Anton

    Light-emitting diodes (LEDs) constitute a rapidly evolving and fast growing technology that promises to replace incandescent bulbs and compact fluorescent lights in many illumination applications. Large-area LED luminaires have a capability to transform lighting by providing a venue for development of smart lighting systems with additional benefits, such as visible light communications, sensing, health and productivity improvement through color temperature control, capability of creating "virtual sky" ceiling, and many others. The objective of this work is to explore directed self-assembly (DSA) approaches suitable for cost-effective assembly of large amount of LEDs and other mesoscopic (i.e. millimeter and sub-millimeter) electronic components and thus to enable manufacturing of smart lighting luminaires. Existing alternative approaches for assembly of semiconductor dies are examined including transfer printing, laser-assisted die transfer, and various directed self-assembly approaches using shape-recognition, magnetic and capillary forces, etc. After comparing their advantages and limitations, we developed two approaches to magnetic force-assisted DSA of LEDs on a large-area substrate in liquid and air medium. The first approach involves pick-up of buoyant and magnetic dies from the liquid surface onto the flexible substrate in a roll-to-roll process. The possibility of high-speed assembly of LED dies is demonstrated, but with a low yield due to the influence of the capillary force of the carrier liquid and the difficulty in ensuring reliable supply of dies to the assembly interface. To overcome the aforementioned challenges this process was modified to assemble the dies by sinking them onto the receiving substrate with a stencil mask on top, demonstrating LED assembly with a very low error rate but at a lower speed. A solder-assisted self-alignment is used to further improve placement precision and to ensure the proper orientation of the dies. The second

  15. A comparison of pediatric basic life support self-led and instructor-led training among nurses.

    Science.gov (United States)

    Vestergaard, Lone D; Løfgren, Bo; Jessen, Casper L; Petersen, Christina B; Wolff, Anne; Nielsen, Henrik V; Krarup, Niels H V

    2017-02-01

    Pediatric cardiac arrest carries a poor prognosis. Basic life support improves survival. Studies on pediatric basic life support (PBLS) training are sparse. The aim of our study was to investigate the effect of self-training in PBLS. We conducted a prospective controlled trial enrolling nurses from pediatric and maternity wards (n=29 in each group). Self-training, including a manikin and access to a web-based video on PBLS, was compared with a 2-h instructor-led course. Two weeks after training, all participants were tested in a mock scenario of pediatric cardiac arrest. Fifteen parameters equivalent to the steps in the PBLS algorithm - for example, effective ventilations, effective chest compressions, calling for help, and correct sequence of actions, were evaluated and rated dichotomously (1=approved or 0=not approved). No difference was observed in the baseline demographics between the self-training group and the instructor-led group. The participants in the self-training group accessed the website 2±1.5 times (mean±SD) and spent 41±25 min on the site. There was no significant difference between the two groups in the overall average score (10.5 in the self-training group vs. 10.0 in the instructor-led group, P=0.51) or in any of the 15 parameters. After the study, all participants felt that they had improved their skills and felt capable of performing PBLS. Self-training is not statistically different to instructor-led training in teaching PBLS. Self-evaluated confidence improved, but showed no difference between groups. PBLS may be disseminated through self-training.

  16. Life-Cycle Assessment of Energy and Environmental Impacts of LED Lighting Products Part 2: LED Manufacturing and Performance

    Energy Technology Data Exchange (ETDEWEB)

    Scholand, Michael; Dillon, Heather E.

    2012-05-01

    Part 2 of the project (this report) uses the conclusions from Part 1 as a point of departure to focus on two objectives: producing a more detailed and conservative assessment of the manufacturing process and providing a comparative LCA with other lighting products based on the improved manufacturing analysis and taking into consideration a wider range of environmental impacts. In this study, we first analyzed the manufacturing process for a white-light LED (based on a sapphire-substrate, blue-light, gallium-nitride LED pumping a yellow phosphor), to understand the impacts of the manufacturing process. We then conducted a comparative LCA, looking at the impacts associated with the Philips Master LEDbulb and comparing those to a CFL and an incandescent lamp. The comparison took into account the Philips Master LEDbulb as it is now in 2012 and then projected forward what it might be in 2017, accounting for some of the anticipated improvements in LED manufacturing, performance and driver electronics.

  17. Sedimentation problems and solutions

    International Nuclear Information System (INIS)

    Williams, D.T.

    1991-01-01

    Roseires Dam and reservoir are located in Sudan, Africa on the Blue Nile River. The hydropower from the reservoir provides approximately 80% of the power used in Sudan, thus having a tremendous economic impact on the country. The reservoir was first impounded in 1966 and has been filled annually since then. The Blue Nile has historically been known to carry heavy sediment loads which is associated with erosion from overgrazing in Ethiopia, the Blue Nile's headwaters. During the flood season, the dam's turbine intakes become blocked with debris and sediment. After a severe blockage in 1981, which prevented hydropower generation for several days, consultants from USAID were asked to make recommendations on reducing the sediment and debris impacts on reservoir operations. This led to debris clearing and dredging equipment acquisitions in 1982. In 1988, blockage occurred again during the flood season. This writer was asked by the World Bank to travel to Sudan, investigate the sediment and debris problems, examine the USAID recommendations, comment on potential sediment and debris problems associated with a proposed plan to raise the dam, make additional recommendations, and return to Sudan several times to determine the effectiveness of there recommendations. This paper discussed the results of the aforementioned activities and describes the new recommendations made by this writer

  18. Urban Environmental Problems

    International Nuclear Information System (INIS)

    Situma, F.D.P.

    1999-01-01

    The rapid urbanization and resultant heavy concentration of population in urban centres have led to many urban areas failing to provide the necessary infrastructure and amenities as the demands placed on them have overwhelmed their financial and institutional capacities. In many urban areas, the capacity for resource mobilization and delivery of social services has either broken down completely or tethers on breaking point. Although in 1986 the GoK launched a new strategy for the balanced development of rural and urban areas aimed at avoiding excessive concentration of population in urban areas, the fruits of this strategy are yet to be realized. As a result, developments in urban areas have been unsustainable and environmentally unsound. The general quality of the environment has deteriorated so much so that urgent policy intervention is required. Appropriate environmental management measures and practices are needed to address the current trend of spiralling environmental problems in the context of the existing legal and institutional frameworks and makes some proposals for reform to address these problems in order to make urban areas environmentally

  19. Feedback-Controlled LED Photobioreactor for Photophysiological Studies of Cyanobacteria

    Energy Technology Data Exchange (ETDEWEB)

    Melnicki, Matthew R.; Pinchuk, Grigoriy E.; Hill, Eric A.; Kucek, Leo A.; Stolyar, Sergey; Fredrickson, Jim K.; Konopka, Allan; Beliaev, Alex S.

    2013-04-09

    A custom photobioreactor (PBR) was designed to enable automatic light adjustments using computerized feedback control. A black anodized aluminum enclosure, constructed to surround the borosilicate reactor vessel, prevents the transmission of ambient light and serves as a mount for arrays of light-emitting diodes (LEDs). The high-output LEDs provide narrow-band light of either 630 or 680 nm for preferential excitation of the cyanobacterial light-harvesting pigments, phycobilin or chlorophyll a, respectively. Custom developed software BioLume provides automatic control of optical properties and a computer feedback loop can automatically adjust the incident irradiance as necessary to maintain a fixed transmitted light through the culture, based on user-determined set points. This feedback control serves to compensate for culture dynamics which have optical effects, (e.g., changing cell density, pigment adaptations) and thus can determine the appropriate light conditions for physiological comparisons or to cultivate light-sensitive strains, without prior analyses. The LED PBR may also be controlled as a turbidostat, using a feedback loop to continuously adjust the rate of media-dilution based on the transmitted light measurements, with a fast and precise response. This cultivation system gains further merit as a high-performance analytical device, using non-invasive tools (e.g., dissolved gas sensors, online mass spectrometry) to automate real-time measurements, thus permitting unsupervised experiments to search for optimal growth conditions, to monitor physiological responses to perturbations, as well as to quantitate photophysiological parameters using an in situ light-saturation response routine.

  20. Review of practice-led research in art, design & architecture

    OpenAIRE

    Rust, Chris; Mottram, Judith; Till, Jeremy

    2007-01-01

    This review report sets out the outcomes of a 10 month investigation to describe the landscape of practice-led research in Art, Design and Architecture (ADA) in the UK and beyond. We were asked for a qualitative review but of course it has been important to gather some numbers to check and illustrate our observations. We have consulted widely, both face to face and in the virtual world, with experts and novices in the UK and around the world. We have tried to strike a balance between the natu...

  1. Electronic homogeneity of nanowire heterostructure Light Emitting Diodes (LEDs)

    Science.gov (United States)

    Selcu, Camelia; May, Brelon J.; Sarwar, A. T. M. Golam; Myers, Roberto C.

    In addition to low defect densities and great tunability bandgap within a single heterostructure, the possibility of growing (Al, In,_) GaN nanowire heterostructure LEDs on different substrates while maintaining their high electronic and optical properties makes them very attractive. We investigated the electronic homogeneity of the (Al, In,_) GaN nanowire ensemble by acquiring current maps at certain applied biases using conductive AFM. By taken IVs on individual nanowires, we found that different wires have different turn on voltages and that some of the nanowires degrade due to the applied bias.

  2. Iluminación led y color en materiales retroreflectivos

    OpenAIRE

    Ferreyra, Simón

    2016-01-01

    La rápida mejora de las prestaciones lumínicas del diodo emisor de luz (LEO} ha generado una importante difusión de esta tecnología en el campo de la iluminación doméstica y comercial, que se está extendiendo ahora al alumbrado público, vial y vehicular. Este trabajo estudia la posible alteración en la reproducción de los colores de materiales retrorreflectivos, cuando se utiliza iluminación LEO. El objetivo de este trabajo es evaluar los cambios de color que genera la iluminación LED en mues...

  3. Heat Transfer Characteristics in High Power LED Packaging

    Directory of Open Access Journals (Sweden)

    Chi-Hung Chung

    2014-03-01

    Full Text Available This study uses the T3Ster transient thermal resistance measuring device to investigate the effects to heat transfer performances from different LED crystal grains, packaging methods and heat-sink substrates through the experimental method. The experimental parameters are six different types of LED modules that are made alternatively with the crystal grain structure, the die attach method and the carrying substrate. The crystal grain structure includes the lateral type, flip chip type and vertical type. The die attach method includes silver paste and the eutectic structure. The carrying substrates are aluminum oxide (Alumina and aluminum nitride (AIN ceramic substrates and metal core PCB (MCPCB. The experimental results show that, under the conditions of the same crystal grain and die attach method, the thermal resistance values for the AIN substrate and the Alumina substrate are 2.1K/W and 5.1K/W, respectively and the total thermal resistance values are 7.3K/W and 10.8K/W. Compared to the Alumina substrate, the AIN substrate can effectively lower the total thermal resistance value by 32.4%. This is because the heat transfer coefficient of the AIN substrate is higher than that of the Alumina substrate, thus effectively increasing its thermal conductivity. In addition, under the conditions of the same crystal grain and the same substrate, the packaging methods are using silver paste and the eutectic structure for die attach. Their thermal resistance values are 5.7K/W and 2.7K/W, respectively, with a variance of 3K/W. Comparisons of the crystal grain structure show that the thermal resistance for the flip chip type is lower than that of the traditional lateral type by 0.9K/W. This is because the light emitting layer of the flip chip crystal grain is closer to the heat-sink substrate, shortening the heat dissipation route, and thus lowering the thermal resistance value. For the total thermal resistance, the crystal grain structure has a lesser

  4. A user-led approach to information systems investments

    International Nuclear Information System (INIS)

    Pferd, J.W.; Fuller, A.G.

    1993-01-01

    Information-system (IS) expenditures for upstream E ampersand P have come under strong review along with other overhead expenses. Increasing frustration with IS budgets and concern about their business value led Unocal Corp. to change the way it begins, manages, and implements IS projects. Successful IS investments are aligned with the goals and functions of work groups or business units and are balanced against other investments. The twin demands of business needs and sound technical design must be served together to achieve long-term success from IS investments. This paper describes project organizations and methods to achieve these two objectives

  5. Exploring Service-led Growth Trajectories for Analytical Equipment Providers

    DEFF Research Database (Denmark)

    Raja, Jawwad; Frandsen, Thomas; Mouritsen, Jan

    2016-01-01

    This paper examines the dilemmas encountered by advanced analytical equipment providers in developing service-led growth strategies to expand their business in pursuit of more attractive revenue models. It does so by adopting a case based research approach. The findings detail the capabilities...... required to provide advanced services within customers’ R&D functions, while simultaneously attempting to scale these for a production context. The emergent complexities of operating in multiple arenas in order to explore and exploit technologies-along the three trajectories of serviceability, scalability...

  6. Simple LED spectrophotometer for analysis of color information.

    Science.gov (United States)

    Kim, Ji-Sun; Kim, A-Hee; Oh, Han-Byeol; Goh, Bong-Jun; Lee, Eun-Suk; Kim, Jun-Sik; Jung, Gu-In; Baek, Jin-Young; Jun, Jae-Hoon

    2015-01-01

    A spectrophotometer is the basic measuring equipment essential to most research activity fields requiring samples to be measured, such as physics, biotechnology and food engineering. This paper proposes a system that is able to detect sample concentration and color information by using LED and color sensor. Purity and wavelength information can be detected by CIE diagram, and the concentration can be estimated with purity information. This method is more economical and efficient than existing spectrophotometry, and can also be used by ordinary persons. This contribution is applicable to a number of fields because it can be used as a colorimeter to detect the wavelength and purity of samples.

  7. Patent Deployment Strategies and Patent Value in LED Industry.

    Science.gov (United States)

    Wu, Ming-Fu; Chang, Keng-Wei; Zhou, Wei; Hao, Juan; Yuan, Chien-Chung; Chang, Ke-Chiun

    2015-01-01

    This study applies two variables in the measurement of company patent deployment strategies: patent family depth and earn plan ratio. Patent family depth represents the degree to which certain fields and markets are valued by the patent owner. Earn plan ratio defined as the ratio of the number of patent forward citations to patent family size. Earn plan ratio indicates the degree to which a patent family could be cited by later innovators and competitors. This study applies a logistic regression model in the analysis LED industry data. The results demonstrate that patent value has a positive relationship with the patent family depth, and earn plan ratio.

  8. A lifetime prediction method for LEDs considering mission profiles

    DEFF Research Database (Denmark)

    Qu, Xiaohui; Wang, Huai; Zhan, Xiaoqing

    2016-01-01

    and to benchmark the cost-competitiveness of different lighting technologies. The existing lifetime data released by LED manufacturers or standard organizations are usually applicable only for specific temperature and current levels. Significant lifetime discrepancies may be observed in field operations due...... to the varying operational and environmental conditions during the entire service time (i.e., mission profiles). To overcome the challenge, this paper proposes an advanced lifetime prediction method, which takes into account the field operation mission profiles and the statistical properties of the life data...

  9. A Lifetime Prediction Method for LEDs Considering Real Mission Profiles

    DEFF Research Database (Denmark)

    Qu, Xiaohui; Wang, Huai; Zhan, Xiaoqing

    2017-01-01

    and to benchmark the cost-competitiveness of different lighting technologies. However, the existing lifetime data released by LED manufacturers or standard organizations are usually applicable only for some specific temperature and current levels. Significant lifetime discrepancies may be seen in the field...... operations due to the varying operational and environmental conditions during the entire service time (i.e., mission profiles). To overcome the challenge, this paper proposes an advanced lifetime prediction method, which takes into account the field operation mission profiles and also the statistical...

  10. 78 FR 5207 - Certain Led Photographic Lighting Devices and Components Thereof; Commission's Final...

    Science.gov (United States)

    2013-01-24

    ... COMMISSION Certain Led Photographic Lighting Devices and Components Thereof; Commission's Final Determination... general exclusion order prohibiting importation of infringing LED photographic lighting devices and... importation of certain LED photographic lighting devices and components thereof that infringe certain claims...

  11. Development of LED light sources and lamps. Final report; Slutrapport for PSO 337-068. Udvikling af LED lyskilder og lamper

    Energy Technology Data Exchange (ETDEWEB)

    Dam-Hansen, C.; Petersen, Paul Michael; Thestrup, B.; Scharling Holm, J.; Munkgaard Andersen, J.; Falleboe, H.; Olsen, Jesper; Flindt, C.

    2007-04-15

    This report is the final and concluding report on the research and development project 'Development of LED light sources and lamps' PSO no. 337-068 supported by Dansk Energi - Net. The project was a collaboration between Risoe National laboratory, Louis Poulsen Lighting, Dong Energy, Laboratoriet Lys & Syn and RGB Lamps. The objective of this project was to pave the way for replacement of incandescent- and halogen lighting by LED lightning through development of prototypes for new types of LED products: light sources and lamps. The report summarizes and describes the main results of the project, which are: 1) a new LED light source with an efficacy of 51 lm/W and a CRI index of 92 that can replace an incandescent bulb. 2) two LED pendants/lamps, a LED table lamp and a chair with LED lighting developed by designers and researchers. 3) LED seminar and two exhibitions of the newly developed LED products and user test by questionnaires. 4) A new startup company 'Morfoso'. 5) Developed course on light and LED technology for designers. 6) A new LED light laboratory for test and characterization of LED components and LED light sources and lamps. (au)

  12. Problem Solving Treatment for Intellectually Disabled Sex Offenders

    Science.gov (United States)

    Nezu, Christine Maguth; Fiore, Alicia A.; Nezu, Arthur M.

    2006-01-01

    Over the past thirty years, Problem Solving Therapy (PST) has been shown to be an effective treatment for many different problems and patient populations (Nezu, 2004). Among its many clinical applications, PST interventions were developed for persons with intellectually disabilities (ID), where improving problem-solving skills led to adaptive…

  13. Food irradiation - Problems and promises

    International Nuclear Information System (INIS)

    Hickman, J.R.

    1974-01-01

    It has been stated that food irradiation represents the most significant discovery in food processing since Nicholas Appert invented canning in 1810. Certainly it is a process with great future potential; it is attractive because it works without heating the product, it is effective within sealed containers as well as for bulk usage, and it does not leave chemical residues on the treated food. Of course, no one process can be expected to solve all problems relating to preservation of food. Ionizing radiation can be used effectively to solve many of these problems, but the process is no panacea to cure the world's food problems. Unfortunately, early ill-founded claims about irradiation led to expectations which have proved beyond the reasonable capabilities of the process. Nevertheless, the number of foods that have been successfully treated, and the broad range of effects that can be achieved by radiation processing is impressive. (author)

  14. Improvement of efficiency droop in resonance tunneling LEDs

    Science.gov (United States)

    Liu, Chaowang; Wang, Wang N.; Shields, Philip A.; Denchitcharoen, Somyod; Causa, Federica; Allsopp, Duncan E. W.

    2008-08-01

    A resonance tunnelling LED structure having a high efficiency, low droop and negligible wavelength shift with current is reported in this study. The LED structure contains a thick InGaN bottom spacer between an n-GaN contact layer and a multiple quantum well (MQW) active region, and a thin InGaN top spacer between the MQW and an AlGaN electron blocking layer (EBL). The observed high efficiency and negligible wavelength shift with applied current are attributed to the thick InGaN bottom spacer that nucleates V-pits and acts as a strain control layer for the MQW. The thick InGaN layer also provides an electron reservoir for efficient electron tunnelling injection into the MQW and reduces the electropotential difference between the n-emitter and the p-emitter, to suppress current leakage at high driving current and reduce droop. The top InGaN spacer was designed to act as a magnesium back-diffusion barrier and strain relief layer from EBL so as to obtain high efficiency.

  15. Reliable LED Lighting Technologies: Key Factors and Procurement Guidance

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Lynn; Arquit Niederberger, Anne

    2015-10-08

    Abstract— Lighting systems have the ability to transform the economic and educational infrastructure of disadvantaged communities, and eradicating “light poverty” has become one of the primary goals of the International Year of Light 2015. Solid-state lighting (SSL) technology, based on light-emitting diode (LED) light sources, has emerged as the next generation of lighting technology, with a current global market penetration of roughly 5%. This paper will report on recent research on understanding SSL lighting system reliability (failure modes, environmental stressors, electrical power quality); discuss the implications of SSL technology reliability for providing lighting services; and suggest practical approaches to ensure SSL reliability to benefit humanity. Among the key findings from this work is that LED sources can be extremely reliable, withstanding a broad range of environmental stresses without failure. Nonetheless, SSL lighting systems can have a negative impact on electrical power reliability, as well as on the affordability of lighting services, without attention to the quality of the accompanying power infrastructure. It is therefore critical to ensure that the performance of the power supply electronics used in lighting systems is matched to the quality of the power source, when evaluating energy efficient lighting choices.

  16. [Midwife-led birth centres: an alternative to hospital childbirth?].

    Science.gov (United States)

    Bauer, S; Kötter, C

    2013-02-01

    After midwife-led birth centres had been included into the Social Security Statute Book (§134a SGB V) and thus become covered by German Public Health Insurance since April 1st, 2007 contract negotiations on flat rate costs have followed. Meanwhile the 2nd edition of this -agreement has come into effect. The present contribution describes how this non-hospital obstetric care has developed in the last 3 years. The medical care situation is explained based on legal conditions. Special attention is paid to regulations concerning quality management as well as the certification or auditing required to remain listed in the national register of midwife-led units at the Social Health Insurance. Results are shown from data collected by the Associa-tion for Quality Assurance on Out-of-hospital births (QUAG) and from a pilot project which also contains comparisons with clinical findings. The discussion refers to data taken from German as well as international publications. The conclusion points out some aspects in need of further development. © Georg Thieme Verlag KG Stuttgart · New York.

  17. Using affordable LED arrays for photo-stimulation of neurons.

    Science.gov (United States)

    Valley, Matthew; Wagner, Sebastian; Gallarda, Benjamin W; Lledo, Pierre-Marie

    2011-11-15

    Standard slice electrophysiology has allowed researchers to probe individual components of neural circuitry by recording electrical responses of single cells in response to electrical or pharmacological manipulations(1,2). With the invention of methods to optically control genetically targeted neurons (optogenetics), researchers now have an unprecedented level of control over specific groups of neurons in the standard slice preparation. In particular, photosensitive channel rhodopsin-2 (ChR2) allows researchers to activate neurons with light(3,4). By combining careful calibration of LED-based photostimulation of ChR2 with standard slice electrophysiology, we are able to probe with greater detail the role of adult-born interneurons in the olfactory bulb, the first central relay of the olfactory system. Using viral expression of ChR2-YFP specifically in adult-born neurons, we can selectively control young adult-born neurons in a milieu of older and mature neurons. Our optical control uses a simple and inexpensive LED system, and we show how this system can be calibrated to understand how much light is needed to evoke spiking activity in single neurons. Hence, brief flashes of blue light can remotely control the firing pattern of ChR2-transduced newborn cells.

  18. Development and commercialisation of rechargeable wooden LED lamps

    Directory of Open Access Journals (Sweden)

    Bradley Schultz

    2013-02-01

    Full Text Available The focus of this project was to work with local staff at Kathmandu Alternative Power and Energy Group to commercialise a product which would generate recurring income for the organisation, to enable staff to learn the process of commercialisation and to provide employment and skills in the local community. Rechargeable Light Emitting Diode (LED lamps were deemed suitable for these aims, as they are a simple product, yet one that is urgently required in Nepal due to the prevalence of ‘load-shedding’ – scheduled electrical blackouts. After reviewing the market, it was found that it would be impossible to compete with the price of cheap imported Chinese rechargeable LED lamps, so an alternative approach was taken. This involved sourcing wooden off-cuts from a local furniture factory and transforming them into attractive desk lamps, with the target market being affluent Nepalis, ex-pats living in Nepal and tourists. Successful initial sales were achieved through a Kathmandu-based ex-pat email group, hotel-markets and souvenir stores. KAPEG staff have continued the project, producing variations on the initial design including Himalayan rock salt lamps, employing local people to manufacture lamps and selling them at markets in Kathmandu. Staffing and marketing challenges remain to ensure the lamp manufacture and sales continue.

  19. The quality study of recycled glass phosphor waste for LED

    Science.gov (United States)

    Tsai, Chun-Chin; Chen, Guan-Hao; Yue, Cheng-Feng; Chen, Cin-Fu; Cheng, Wood-Hi

    2017-02-01

    To study the feasibility and quality of recycled glass phosphor waste for LED packaging, the experiments were conducted to compare optical characteristics between fresh color conversion layer and that made of recycled waste. The fresh color conversion layer was fabricated through sintering pristine mixture of Y.A.G. powder [yellow phosphor (Y3AlO12 : Ce3+). Those recycled waste glass phosphor re-melted to form Secondary Molten Glass Phosphor (S.M.G.P.). The experiments on such low melting temperature glass results showed that transmission rates of S.M.G.P. are 9% higher than those of first-sintered glass phosphor, corresponding to 1.25% greater average bubble size and 36% more bubble coverage area in S.M.G.P. In the recent years, high power LED modules and laser projectors have been requiring higher thermal stability by using glass phosphor materials for light mixing. Nevertheless, phosphor and related materials are too expensive to expand their markets. It seems a right trend and research goal that recycling such waste of high thermal stability and quality materials could be preferably one of feasible cost-down solutions. This technical approach could bring out brighter future for solid lighting and light source module industries.

  20. Student-led leadership training for undergraduate healthcare students.

    Science.gov (United States)

    Sheriff, Ibrahim Hasanyn Naim; Ahmed, Faheem; Jivraj, Naheed; Wan, Jonathan C M; Sampford, Jade; Ahmed, Na'eem

    2017-10-02

    Purpose Effective clinical leadership is crucial to avoid failings in the delivery of safe health care, particularly during a period of increasing scrutiny and cost-constraints for the National Health Service (NHS). However, there is a paucity of leadership training for health-care students, the future leaders of the NHS, which is due in part to overfilled curricula. The purpose of this study was to assess the impact of student-led leadership training for the benefit of fellow students. Design/methodology/approach To address this training gap, a group of multiprofessional students organised a series of large-group seminars and small-group workshops given by notable health-care leaders at a London university over the course of two consecutive years. Findings The majority of students had not previously received any formal exposure to leadership training. Feedback post-events were almost universally positive, though students expressed a preference for experiential teaching of leadership. Working with university faculty, an inaugural essay prize was founded and student members were given the opportunity to complete internships in real-life quality improvement projects. Originality/value Student-led teaching interventions in leadership can help to fill an unmet teaching need and help to better equip the next generation of health-care workers for future roles as leaders within the NHS.

  1. SSL and LED life prediction and assessment of CCT shift

    Energy Technology Data Exchange (ETDEWEB)

    Lall, Pradeep [Auburn Univ., AL (United States); Sakalaus, Peter [Auburn Univ., AL (United States); Wei, Junchao [Auburn Univ., AL (United States); Davis, Lynn [RTI International, Research Triangle Park, NC (United States)

    2014-05-27

    Solid-state lighting (SSL) products can have a predicted life of 70% lumen output (L70) from 26,000 to 40,000 hours using the LM-80-08 testing standards. Chromaticity shift, correlated color temperature (CCT) and lumen maintenance (LM) will dramatically reduce the nominal life of SSL luminaires. In this work, an off-the-shelf luminaire from Philips (AmbientLED) has been aged in a standard wet hot temperature operating life (WHTOL) of 85% relative humidity and 85°C (85/85) in order to assess reliability of prolonged exposer in a harsh environment. Failure criterion has been derived using the Arrhenius equation from the LM-80-08 standard, as well as the 60W LED Lamp test report from an isothermal environment of 45°C. This is a similar luminaire to the test vehicle used in this research. Data characterization between the two data sets has been carried out to determine the luminaires reliability and life under the 85/85 test conditions. This characterization allows for the determination of poor quality luminaire products in the market place. The distribution properties of the shifting mean values of CCT and LM were incorporated into the Bayesian Linear Regression (BLR) to determine the degradation pattern, in order to predict the remaining useful life (RUL) of the system due to aging before the end-of-life (EoL).

  2. LED Curing Lights and Temperature Changes in Different Tooth Sites

    Directory of Open Access Journals (Sweden)

    E. Armellin

    2016-01-01

    Full Text Available Objectives. The aim of this in vitro study was to assess thermal changes on tooth tissues during light exposure using two different LED curing units. The hypothesis was that no temperature increase could be detected within the dental pulp during polymerization irrespective of the use of a composite resin or a light-curing unit. Methods. Caries-free human first molars were selected, pulp residues were removed after root resection, and four calibrated type-J thermocouples were positioned. Two LED lamps were tested; temperature measurements were made on intact teeth and on the same tooth during curing of composite restorations. The data was analyzed by one-way analysis of variance (ANOVA, Wilcoxon test, Kruskal-Wallis test, and Pearson’s χ2. After ANOVA, the Bonferroni multiple comparison test was performed. Results. Polymerization data analysis showed that in the pulp chamber temperature increase was higher than that without resin. Starlight PRO, in the same condition of Valo lamp, showed a lower temperature increase in pre- and intrapolymerization. A control group (without composite resin was evaluated. Significance. Temperature increase during resin curing is a function of the rate of polymerization, due to the exothermic polymerization reaction, the energy from the light unit, and time of exposure.

  3. Effectiveness of nurse-led brief alcohol intervention: a cluster randomized controlled trial.

    Science.gov (United States)

    Lock, Catherine A; Kaner, Eileen; Heather, Nick; Doughty, Julie; Crawshaw, Andrea; McNamee, Paul; Purdy, Sarah; Pearson, Pauline

    2006-05-01

    This paper reports an evaluation of the effectiveness and cost-effectiveness of nurse-led screening and brief intervention in reducing excessive alcohol consumption among patients in primary health care. Excessive alcohol consumption is a major source of social, economic and health problems. However, such consumption is responsive to brief alcohol intervention. To date, brief intervention research in primary health care has focused on general practitioner-led interventions, and there is only circumstantial evidence of effectiveness in nurse-led interventions. However, nurses are increasingly taking a lead in health promotion work in primary care. A pragmatic cluster-randomized controlled trial was carried out between August 2000 and June 2003 to evaluate the effects of a brief intervention compared with standard advice (control condition). A total of 40 general practice clusters (intervention = 21 and control = 19) recruited 127 patients (intervention = 67 and control = 60) to the trial. Excessive consumption was identified opportunistically via the Alcohol Use Disorders Identification Test. After baseline assessment, patients received either a 5-10 minutes brief intervention using the 'Drink-Less' protocol or standard advice (control condition). Follow-up occurred at 6 and 12 months postintervention. Analysis of variance weighted for cluster size revealed no statistically significant differences between intervention and control patients at follow up. A majority of patients in both conditions reduced their alcohol consumption between assessment and subsequent measurement. Economic analysis suggested that the brief intervention led to no statistically significant changes in subsequent health service resource use relative to standard treatment. The brief intervention evaluated in this trial had no effect over standard advice delivered by nurses in primary health care. However, there was a reduction in excessive drinking across both arms of the trial over time. Due to

  4. Intrapartum and neonatal mortality in primary midwife-led and secondary obstetrician-led care in the Amsterdam region of the Netherlands: A retrospective cohort study

    NARCIS (Netherlands)

    Wiegerinck, M.M.J.; van der Goes, B.Y.; Ravelli, A.C.J.; van der Post, J.A.M.; Klinkert, J.; Brandenbarg, J.; Buist, F.C.D.; Wouters, M.G.A.J.; Tamminga, P.; de Jonge, A.; Mol, B.W.

    2015-01-01

    Objective: to compare intrapartum- and neonatal mortality and intervention rates in term women starting labour in primary midwife-led versus secondary obstetrician-led care. Design: retrospective cohort study. Setting: Amsterdam region of the Netherlands. Participants: women with singleton

  5. A cost-comparison of midwife-led compared with consultant-led maternity care in Ireland (the MidU study).

    Science.gov (United States)

    Kenny, Christopher; Devane, Declan; Normand, Charles; Clarke, Mike; Howard, Aoife; Begley, Cecily

    2015-11-01

    to compare the cost of maternity care between two midwife-led units, and their linked consultant-led units, following a large randomised trial in Ireland. ethical approval was received for this unblinded, pragmatic randomised trial (MidU) funded by the Health Service Executive (Dublin North-East, Ireland), conducted 2004-2009. A comparison of costs analysis was conducted on the outcomes from the trial. two maternity units in Ireland, with 'alongside' midwife-led units. all women without risk factors for labour and birth who booked at the two maternity units before 24 weeks׳ gestation were assessed for inclusion. Consenting women (n=1653) were centrally randomised on a 2:1 ratio (1101:552) to midwife-led or consultant-led care. women randomised to consultant-led care received standard care. Women randomised to the midwife-led arm received midwife-led care provided by a small group of midwives in two units, situated ׳alongside׳ the consultant-led units, throughout pregnancy, birth and postnatal. mean difference in clinician salaries, cost of care based on managers׳ data, known costs of postnatal bed days and costs of key interventions were measured. the average cost of caring for a woman allocated to the midwife-led units was €2598, compared to €2780 in the consultant-led units (average difference €182 per woman, analysed by 'intention to treat'). care in these two midwife-led units costs less than care provided by the consultant-led units. Given the clinical findings, which showed that care provided in the midwife-led units is as safe as that in the consultant-led units and results in less intervention, more midwife-led units should be incorporated into maternity care in Ireland so that scarce resources can be used more effectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Stekken onder LED-belichting : verkenning naar de mogelijkheden van het stekken van boomkwekerijgewassen onder LED in een meerlaagssysteem zonder daglicht

    NARCIS (Netherlands)

    Dalfsen, van P.; Slingerland, L.; Roelofs, P.F.M.M.

    2011-01-01

    LED-belichting biedt enorme kansen voor de tuinbouw. Ook in de boomkwekerij biedt LED-belichting perspectief, met name bij het stekken van boomkwekerijgewassen. LED-belichting geeft namelijk specifieke kleuren af, waarmee processen in de plant beïnvloed kunnen worden, zoals beworteling en

  7. Some existence problems regarding partial Latin squares

    OpenAIRE

    Aryapoor, Masood

    2014-01-01

    Latin squares are interesting combinatorial objects with many applications. When working with Latin squares, one is sometimes led to deal with partial Latin squares, a generalization of Latin squares. One of the problems regarding partial Latin square and with applications to Latin squares is whether a partial Latin square with a given set of conditions exists. The goal of this article is to introduce some problems of this kind and answer some existence questions regarding partial Latin squares

  8. GaN-based LEDs grown by molecular beam epitaxy

    Science.gov (United States)

    Averbeck, Robert; Graber, A.; Tews, H.; Bernklau, D.; Barnhoefer, Ulrich; Riechert, Henning

    1998-04-01

    We report on the growth of GaN, InGaN and GaN/InGaN/GaN pn- junctions grown on sapphire by RF-plasma assisted MBE. MBE allows us to grow high quality nitrides with growth rates around 1 micrometers /h at relatively low temperatures. Thereby p- type doping with Mg and the incorporation of In in InGaN are greatly facilitated. Device-typical n- and p-type doping levels yield room temperature mobilities of 220 cm2/Vs and 10 cm2/Vs, respectively. InGaN with In contents of more than 40 percent is readily achieved. LEDs fabricated from heterostructures with a 4 nm InGaN layer show bright blue or green electroluminescence depending on the In content. Various effects in the electroluminescence caused by fluctuations in the conduction and valence band will be discussed, the most striking one a reduction in linewidth with increasing temperature.

  9. LED-Absorption-QEPAS Sensor for Biogas Plants

    Directory of Open Access Journals (Sweden)

    Michael Köhring

    2015-05-01

    Full Text Available A new sensor for methane and carbon dioxide concentration measurements in biogas plants is presented. LEDs in the mid infrared spectral region are implemented as low cost light source. The combination of quartz-enhanced photoacoustic spectroscopy with an absorption path leads to a sensor setup suitable for the harsh application environment. The sensor system contains an electronics unit and the two gas sensors; it was designed to work as standalone device and was tested in a biogas plant for several weeks. Gas concentration dependent measurements show a precision better than 1% in a range between 40% and 60% target gas concentration for both sensors. Concentration dependent measurements with different background gases show a considerable decrease in cross sensitivity against the major components of biogas in direct comparison to common absorption based sensors.

  10. Nurse-Led Trauma-Informed Correctional Care for Women.

    Science.gov (United States)

    Mollard, Elizabeth; Brage Hudson, Diane

    2016-07-01

    Incarcerated women are a vulnerable and unique population of special concern to nurses as they have high rates of mental illness. In this article, the authors discuss how trauma exposure contributes to mental illness in incarcerated women through abuse, socioeconomic factors, and the prison environment, how this trauma exposure manifests in the inmate survivor, and the related implications for practice. A history of trauma and victimization is related to complex mental health issues which affect the majority of justice-involved women. The correctional environment can exacerbate these issues. Nursing implications include discussion of the trauma-informed care model. The authors recommend a model of trauma-informed care named "the 4 Es" that can guide nurses in preparing a trauma-informed correctional environment and discuss the importance of nurse-led policy change in finding alternatives to incarceration for women with mental illness. © 2015 Wiley Periodicals, Inc.

  11. Experiment of solidifying photo sensitive polymer by using UV LED

    Science.gov (United States)

    Kang, Byoung Hun; Shin, Sung Yeol

    2008-11-01

    The development of Nano/Micro manufacturing technologies is growing rapidly and in the same manner, the investments in these areas are increasing. The applications of Nano/Micro technologies are spreading out to semiconductor production technology, biotechnology, environmental engineering, chemical engineering and aerospace. Especially, SLA is one of the most popular applications which is to manufacture 3D shaped microstructure by using UV laser and photo sensitive polymer. To make a high accuracy and precision shape of microstructures that are required from the diverse industrial fields, the information of interaction relationship between the photo resin and the light source is necessary for further research. Experiment of solidifying photo sensitive polymer by using UV LED is the topic of this paper and the purpose of this study is to find out what relationships do the reaction of the resin have in various wavelength, power of the light and time.

  12. Using UAVs to Conduct Student-led Research Projects

    Science.gov (United States)

    Olds, S. E.; Lewis, P. M., Jr.

    2016-12-01

    Recreational drones can inspire students to initiate research projects. These "toys" have a low cost (design skills such as designing a camera mount to obtain nadir or oblique imagery. Learners can also move to more sophisticated research using photogrammetric skills such as taking overlapping photographs to create 3D structure from motion (SfM) models. To encourage the use of onboard sensors, the team worked with an engineer to build a 33-gram prototype environmental logger called SABEL (Shelley [Olds] and Bob [Ellis]'s Environmental Logger). Assembled on an Arduino board, SABEL collects temperature, humidity, and GPS position. This presentation will provide examples of student-led investigations, instructions for building the SABEL sensor package, and the status of the new e-book compilation of student-focused activities using recreational drones to pursue science, math, engineering, and technology research investigations.

  13. An underwater optical wireless communication system based on LED source

    Science.gov (United States)

    Rao, Jionghui; Wei, Wei; Wang, Feng; Zhang, Xiaohui

    2011-11-01

    Compared with other communication methods, optical wireless communication (OWC) holds the merits of higher transmitting rate and sufficient secrecy. So it is an efficacious communicating measure for data transmitting between underwater carriers. However, due to the water attenuation and the transmitter & the receiver (TX/RX) collimation, this application is restrained in underwater mobile carriers. A prototype for underwater OWC was developed, in which a high-powered green LED array was used as the light source which partly raveled the TX/RX collimation out. A small pumped-multiple-tube (PMT) was used as the detector to increase the communicating range, and FPGA chips were employed to code and decode the communicating data. The data rate of the prototype approached to 4 Mb/s at 8.4m and 1 Mb/s at 22m where voice and Morse communications were achieved in a scope of 30 degree TX/RX angle.

  14. A summary of LED lighting impacts on health

    Directory of Open Access Journals (Sweden)

    Cosmin Ticleanu

    2017-06-01

    Full Text Available Lighting can affect the health of people in buildings. This goes beyond the safety aspects of providing enough illumination to see by; lighting affects mood and human circadian rhythms, while poor lighting can cause glare, headaches, eyestrain, aches and pains associated with poor body posture or, in extreme cases, skin conditions and various types of sight loss. These aspects ought to be considered by designers and building owners and occupiers in order to improve the lit environment and use adequate lighting and lighting controls that meet the recommendations of codes and standards. Various types of lighting can have different impacts depending on their spectral, optical and electrical characteristics. This paper discusses potential impacts of LED lighting on human health, and is based on a recent BRE review of research investigating the most typical effects of lighting on human health.

  15. A customer-insight led approach to building operational resilience.

    Science.gov (United States)

    Passey, Fi

    2018-01-01

    High-profile failures over the past few years have led to the disruption of banking services in the UK, with some banks' customers left unable to make or receive payments, check balances or access cash for days or weeks. Technological advances and a push towards remote channels have increased customer expectations of 'always on' - any time, any place, anywhere - and with disruptions lasting anything from a few minutes to nearly a month, the regulator is also taking an interest. Nationwide Building Society has responded positively to this challenge by defining its operational resilience strategy, a long-term plan aimed at minimising the likelihood and impact of future disruptions. Customer research was used in order to understand customer expectations, as well as define and prioritise its end-to-end customer journeys, known as business service lines. A comprehensive mapping exercise facilitated the development of strategies and investment projects to address identified vulnerabilities and increase resilience.

  16. Oppenheimer&Groves : The duality that led to Trinity /.

    Energy Technology Data Exchange (ETDEWEB)

    Connaughton, T. G. (Theresa G.); Smith, S. E. (Sharon E.)

    2001-01-01

    The alliance of J. Robert Oppenheimer, scientist, and Leslie R. Groves, military leader, is often interpreted as the classic example of the clash between the academic mind and the military style. Evidence suggests, instead, that it was a collaboration that led to the dawn of the nuclear age. Instead of a clash, it was collaboration and an implosion of the diverse talents needed for the success of this project. Discussion of these flawed and fascinating individuals still ignites controversy today. This presentation will explore the backgrounds and personalities of these two men and their work together to accomplish their mission. Was the aftermath inevitable, given a relationship based on respect, but perhaps not trust? The genesis of the modern military-industrial complex rested on the genius of these two men, though they personify two distinct American sub-cultures. What lessons can be drawn from their wartime and post-war relationship? What analogies can be drawn for current American values?

  17. LED Lightbulbs as a Source of Electricity Saving in Buildings

    Directory of Open Access Journals (Sweden)

    Zeb Akhtar

    2016-01-01

    Full Text Available Today a number of renewable energy technologies are available for power generation, but fossil fuels are still providing a dominant share nevertheless. In order to decrease the electric bill and save our environment, energy conservation is always crucial. In this paper a very interesting idea is presented which is economically viable to reduce electricity usage in our buildings. An effort has been made to estimate the amount of energy that could be saved in the dormitory section of the IMOP building in Russia. Although there are many ways to reduce the consumption of electricity in this building but here the emphasis is on changing light bulbs inside the rooms, kitchen, toilet and bathroom of each apartment. The scope of the study is to figure out monthly electricity saving by replacing traditional light bulbs by LED light bulbs in the building under consideration. The total investment required and the payback period is also presented.

  18. DMPonline Version 4.0: User-Led Innovation

    Directory of Open Access Journals (Sweden)

    Magdalena Getler

    2014-07-01

    Full Text Available DMPonline is a web-based tool to help researchers and research support staff produce data management and sharing plans. Between October and December 2012, we examined DMPonline in unprecedented detail. The results of this evaluation led to some major changes. We have shortened the DCC Checklist for a Data Management Plan and revised how this is used in the tool. We have also amended the data model for DMPonline, improved workflows and redesigned the user interface. This paper reports on the evaluation, outlining the methods used, the results gathered and how they have been acted upon. We conducted usability testing on v.3 of DMPonline and the v.4 beta prior to release. The results from these two rounds of usability testing are compared to validate the changes made. We also put forward future plans for a more iterative development approach and greater community input.

  19. Big Data-Led Cancer Research, Application, and Insights.

    Science.gov (United States)

    Brown, James A L; Ni Chonghaile, Triona; Matchett, Kyle B; Lynam-Lennon, Niamh; Kiely, Patrick A

    2016-11-01

    Insights distilled from integrating multiple big-data or "omic" datasets have revealed functional hierarchies of molecular networks driving tumorigenesis and modifiers of treatment response. Identifying these novel key regulatory and dysregulated elements is now informing personalized medicine. Crucially, although there are many advantages to this approach, there are several key considerations to address. Here, we examine how this big data-led approach is impacting many diverse areas of cancer research, through review of the key presentations given at the Irish Association for Cancer Research Meeting and importantly how the results may be applied to positively affect patient outcomes. Cancer Res; 76(21); 6167-70. ©2016 AACR. ©2016 American Association for Cancer Research.

  20. Hardness Evaluation of Composite Resins Cured with QTH and LED

    Directory of Open Access Journals (Sweden)

    Behnaz Esmaeili

    2014-03-01

    Full Text Available Background and aims. Today light cured composites are widely used. Physical and mechanical properties of composites are related to the degree of conversion. Light curing unit (LCU is an important factor for composite polymerization. Aim of this study is evaluation of composite resins hardness using halogen and LED light curing units. Materials and methods. In this study, 30 samples of Filtek Z250 and C-Fill composite resins were provided. Samples were light cured with Ultralume2, Valo and Astralis7. Vickers hardness number (VHN was measured in 0, 1, 2 mm depth. Statistical analysis used: Data were analysed by SPSS software and compared with each other by T-test, one-way and twoway ANOVA and Post-hoc Tukey test. Results. In Filtek Z250, at top surface, VHN of Ultralume2 was higher than VHN of Valo (P = 0.02 and Astralis7 (P = 0.04, but in depth of 1, 2 mm, VHN of Ultralume2 and Astralis7 were almost the same and both LCUs were more than Valo which the difference between Ultralume2 and Valo was significant in depth of 1mm (0.05 and 2mm (0.02. In C-Fill composite, at top surface, Astralis7 showed higher VHN, but in depth of 2 mm, performance of all devices were rather similar. Conclusion. In Z250, which contains camphorquinone initiator, light cure LED Ultra-lume2 with narrow wavelength showed higher hardness number than Valo. In C-fill, in top surface, Astralis7 with more exposure time, resulted higher VHN. But In depth of 2 mm, various light curing devices had rather similar hardness number.