WorldWideScience

Sample records for fibres scientific issues

  1. Health effects of refractory ceramic fibres: scientific issues and policy considerations.

    OpenAIRE

    Glass, L R; Brown, R. C.; Hoskins, J A

    1995-01-01

    OBJECTIVES--To review the scientific literature on the health effects of refractory ceramic fibres (RCFs). The adverse effects of exposure to asbestos has led to concern about the potential for other fibrous materials to cause diseases. For this reason the human populations most heavily exposed to synthetic mineral fibres have been examined for any adverse effects and many types of fibre have been studied in animal experiments. One type of man made vitreous fibres (MMVFs), refractory ceramic ...

  2. NOAA issues scientific integrity policy

    Science.gov (United States)

    Showstack, Randy

    2011-12-01

    The U.S. National Oceanic and Atmospheric Administration (NOAA) announced the agency's first-ever scientific integrity policy at a 7 December news briefing at the AGU Fall Meeting in San Francisco, Calif. The policy follows a December 2010 White House memorandum that issued guidance to federal agencies implementing scientific integrity policies (see "White House issues scientific integrity policies," Eos Trans. AGU, 91(51), 503, doi:10.1029/2010EO510003, 2010). The purpose of the NOAA policy is "to promote a continuing culture of scientific excellence and integrity, and to establish a policy on the integrity of scientific activities that the agency conducts and uses to inform management and policy decisions," the agency's administrative order states. "In addition, the intent of the policy is to strengthen widespread confidence—from scientists, to decisionmakers, to the general public—in the quality, validity, and reliability of NOAA science and to denote the agency's commitment to a culture of support for excellence of NOAA's principal science asset, its employees."

  3. Asbestos: scientific basis for environmental control of fibres.

    Science.gov (United States)

    Acheson, E D; Gardner, M J

    1980-01-01

    Any review of the scientific evidence on which public policy is based must commence with a cautionary statement about the quality of the available data both about dust and about asbestos-related disease. Attention is drawn to some of the main problems. It is concluded that, in spite of their shortcomings, the data are sufficiently consistent to be useful in relation to some aspects of the problem of environmental control of the asbestos hazard. The question whether or not there is a threshold dose of fibre below which no biological effect occurs is of considerable importance in framing public policy. The evidence concerning the existence or otherwise of a threshold in relation to the different asbestos-related diseases is summarized. A summary is also given of the evidence about the shape of the dose-response curves for asbestos-related diseases in man. The paper concludes with a note on how scientific data may be summarized in a manner which may be helpful in formulating public policy with regard to a control limit.

  4. The scaling issue: scientific opportunities

    Science.gov (United States)

    Orbach, Raymond L.

    2009-07-01

    A brief history of the Leadership Computing Facility (LCF) initiative is presented, along with the importance of SciDAC to the initiative. The initiative led to the initiation of the Innovative and Novel Computational Impact on Theory and Experiment program (INCITE), open to all researchers in the US and abroad, and based solely on scientific merit through peer review, awarding sizeable allocations (typically millions of processor-hours per project). The development of the nation's LCFs has enabled available INCITE processor-hours to double roughly every eight months since its inception in 2004. The 'top ten' LCF accomplishments in 2009 illustrate the breadth of the scientific program, while the 75 million processor hours allocated to American business since 2006 highlight INCITE contributions to US competitiveness. The extrapolation of INCITE processor hours into the future brings new possibilities for many 'classic' scaling problems. Complex systems and atomic displacements to cracks are but two examples. However, even with increasing computational speeds, the development of theory, numerical representations, algorithms, and efficient implementation are required for substantial success, exhibiting the crucial role that SciDAC will play.

  5. Workshop on Scientific Issues in Multiphase Flow

    Energy Technology Data Exchange (ETDEWEB)

    Hanratty, Thomas J. [Univ. of Illinois, Urbana, IL (United States)

    2003-01-02

    This report outlines scientific issues whose resolution will help advance and define the field of multiphase flow. It presents the findings of four study groups and of a workshop sponsored by the Program on Engineering Physics of the Department of Energy. The reason why multiphase flows are much more difficult to analyze than single phase flows is that the phases assume a large number of complicated configurations. Therefore, it should not be surprising that the understanding of why the phases configure in a certain way is the principal scientific issue. Research is needed which identifies the microphysics controlling the organization of the phases, which develops physical models for the resultant multi-scale interactions and which tests their validity in integrative experiments/theories that look at the behavior of a system. New experimental techniques and recently developed direct numerical simulations will play important roles in this endeavor. In gas-liquid flows a top priority is to develop an understanding of why the liquid phase in quasi fully-developed pipe flow changes from one configuration to another. Mixing flows offer a more complicated situation in which several patterns can exist at the same time. They introduce new physical challenges. A second priority is to provide a quantitative description of the phase distribution for selected fully-developed flows and for simple mixing flows (that could include heat transfer and phase change). Microphysical problems of interest are identified – including the coupling of molecular and macroscopic behavior that can be observed in many situations and the formation/destruction of interfaces in the coalescence/breakup of drops and bubbles. Solid-fluid flows offer a simpler system in that interfaces are not changing. However, a variety of patterns exist, that depend on the properties of the particles, their concentration and the Reynolds number characterizing the relative velocity. A top priority is the

  6. Lakatos' Scientific Research Programmes as a Framework for Analysing Informal Argumentation about Socio-Scientific Issues

    Science.gov (United States)

    Chang, Shu-Nu; Chiu, Mei-Hung

    2008-01-01

    The purpose of this study is to explore how Lakatos' scientific research programmes might serve as a theoretical framework for representing and evaluating informal argumentation about socio-scientific issues. Seventy undergraduate science and non-science majors were asked to make written arguments about four socio-scientific issues. Our analysis…

  7. The Successful Scientific Periodicals: Contemporary Issues

    Directory of Open Access Journals (Sweden)

    B.V. Toshev

    2014-12-01

    Full Text Available The new scientific results should be published. However, the scientific result will be lost in inappropriate choice of the media in which is expected to appear. The world periodicals are developed in two levels, parts of the World System of Abstracting, Indexing and Evaluation, WSAIE. This system is just the body of the world science. The first level consists of the primary research journals. After careful inspection these journals should be accepted for covering in secondary research sources; the latter build the second level of the system. Journals, which are not presented in secondary research sources, are considered as marginal and the submission of manuscripts to such journals is not recommended. The second level of WSAIE has an elite part, an American one (Thomson Reuters, Web of Science, and an European one (Elsevier, SCOPUS. The journals of Web of Science are characterized by their impact factor, IF; the journals of SCOPUS are characterized by their im-pact rank, SJR; these journals' scientometric characteristics are entirely equal in use; no one of them should be favoured in respect to the other. However, these factors characterize the journals, not authors publishing in them; there-fore, these numbers cannot be used neither to compare different scientific areas nor in the personal evaluation of authors' scientific activity. The personal and institutional competencies for research could be estimated by properly use of some scientometric variables. The most important of them are considered. Amongst them are the index of Hirsch, h, and the factor of efficiency, e. In twenty-first century a new development of science began. The researchers should know the features of the contemporary science policy; otherwise the traps of the new time would compromise the effort of the researcher to achieve a success in his/her research activity. The status and the new developments in world science are both discussed. The transition from the 'normal

  8. Examination of Students' Small Groups Discussion in Argumentation Process: Scientific and Socio-Scientific Issues

    Science.gov (United States)

    Memis, Esra Kabatas; Cevik, Ebru Ezberci

    2017-01-01

    The purpose of this study was to examine processes experienced by students of different achievement levels in small group discussions in argumentation applications conducted in scientific and socio-scientific issues. Case study which is a qualitative research design was used for the study. In this line, a success test including mechanical subjects…

  9. 3D Bioprinting Technology: Scientific Aspects and Ethical Issues.

    Science.gov (United States)

    Patuzzo, Sara; Goracci, Giada; Gasperini, Luca; Ciliberti, Rosagemma

    2017-06-28

    The scientific development of 3D bioprinting is rapidly advancing. This innovative technology involves many ethical and regulatory issues, including theoretical, source, transplantation and enhancement, animal welfare, economic, safety and information arguments. 3D bioprinting technology requires an adequate bioethical debate in order to develop regulations in the interest both of public health and the development of research. This paper aims to initiate and promote ethical debate. The authors examine scientific aspects of 3D bioprinting technology and explore related ethical issues, with special regard to the protection of individual rights and transparency of research. In common with all new biotechnologies, 3D bioprinting technology involves both opportunities and risks. Consequently, several scientific and ethical issues need to be addressed. A bioethical debate should be carefully increased through a multidisciplinary approach among experts and also among the public.

  10. Academic and Scientific Misconduct: Issues for Nursing Educators.

    Science.gov (United States)

    Hansen, Barbara C.; Hansen, Kenneth D.

    1995-01-01

    Academic and scientific misconduct is coming to public attention. Issues to be resolved include definitions of misconduct, provision for anonymity, role of whistleblowers, burden of proof, statute of limitations, due process, nature and application of sanctions, and potential for rehabilitation. (SK)

  11. [Seed geography: its concept and basic scientific issues].

    Science.gov (United States)

    Yu, Shun-Li; Wang, Zong-Shuai; Zeren, Wangmu

    2010-01-01

    In this paper, a new concept 'seed geography' was provided, and its definition, research contents, and scientific issues were put forward. Seed geography is a newly developed interdisciplinary science from plant geography, seed ecology, and phytosociology, which studies the geographic variation patterns of seed biological traits as well as their relationships with environmental factors from macroscopic to microscopic, and the seed formation, development, and change trends. The main research contents would include geography of seed mass, geography of seed chemical components, geography of seed morphology, geography of seed cell biological characteristics, geography of seed physiological characteristics, geography of seed genetic characteristics, and geography of flower and fruit. To explore the scientific issues in seed geography would help us to better understand the long-term adaptation and evolution of seed characteristics to natural environments.

  12. The Data Issue: Opportunities and Challenges for Scientific Publishers

    Science.gov (United States)

    Murphy, F.; Irving, D. H.

    2011-12-01

    Using the recent report for the 'Opportunities in Data Exchange' Project produced by - and for - researchers, libraries/data centres and publishers (and which is based on a broad range of studies, questionnaires and evidence) we have defined current practices and expectations, and the gaps and dilemmas involved in producing data and datasets, and then analysed their relationship to formal publications. As a result, we identified potential opportunities to evolve scientific insights to be more useful and re-useful: with consequent implications for custodianship and long-term data management. We also defined a number of key incentives and barriers towards achieving these objectives. As a case study, the earth and environmental sciences have come under particularly close scrutiny with respect to data-ownership and -sharing arrangements, sometimes with damaging results to the discipline's reputation. These issues, along with considerable technological challenges, have to be handled effectively in order to best support all the users along the data chain. To that end, we show that key stakeholders - among them scientific publishers - need to have a clear idea of how to progress data-intensive derived information, which we demonstrate is often not the case. Towards bridging this knowledge gap, we have compiled a roadmap of next steps and key issues to be acknowledged and addressed by the scientific publishing community. These include: engaging directly with researchers, policy-makers, funding bodies and direct competitors to build innovative partnerships and enhance impact; providing technological and training investment and developing alongside the emerging discipline of 'data scientist': the 'data publisher'. This individual/company will need to combine a close understanding of researchers' priorities, together with market, legal and technical opportunities and restrictions.

  13. Nature of Science, Scientific Inquiry, and Socio-Scientific Issues Arising from Genetics: A Pathway to Developing a Scientifically Literate Citizenry

    Science.gov (United States)

    Lederman, Norman G.; Antink, Allison; Bartos, Stephen

    2014-01-01

    The primary focus of this article is to illustrate how teachers can use contemporary socio-scientific issues to teach students about nature of scientific knowledge as well as address the science subject matter embedded in the issues. The article provides an initial discussion about the various aspects of nature of scientific knowledge that are…

  14. Nature of Science, Scientific Inquiry, and Socio-Scientific Issues Arising from Genetics: A Pathway to Developing a Scientifically Literate Citizenry

    Science.gov (United States)

    Lederman, Norman G.; Antink, Allison; Bartos, Stephen

    2014-01-01

    The primary focus of this article is to illustrate how teachers can use contemporary socio-scientific issues to teach students about nature of scientific knowledge as well as address the science subject matter embedded in the issues. The article provides an initial discussion about the various aspects of nature of scientific knowledge that are…

  15. History of artificial cold, scientific, technological and cultural issues

    CERN Document Server

    2014-01-01

    The history of artificial cold has been a rather intriguing interdisciplinary subject (physics, chemistry, technology, sociology, economics, anthropology, consumer studies) which despite some excellent monographs and research papers, has not been systematically exploited. It is a subject with all kinds of scientific, technological as well as cultural dimensions. For example, the common home refrigerator has brought about unimaginably deep changes to our everyday lives changing drastically eating habits and shopping mentalities. From the end of the 19th century to the beginning of the 21st, issues related to the production and exploitation of artificial cold have never stopped to provide us with an incredibly interesting set of phenomena, novel theoretical explanations, amazing possibilities concerning technological applications and all encompassing cultural repercussions. The discovery of the unexpected and “bizarre” phenomena of superconductivity and superfluidity, the necessity to incorporate macroscopi...

  16. Extrinsic and intrinsic motivation at 30: Unresolved scientific issues.

    Science.gov (United States)

    Reiss, Steven

    2005-01-01

    The undermining effect of extrinsic reward on intrinsic motivation remains unproven. The key unresolved issues are construct invalidity (all four definitions are unproved and two are illogical); measurement unreliability (the free-choice measure requires unreliable, subjective judgments to infer intrinsic motivation); inadequate experimental controls (negative affect and novelty, not cognitive evaluation, may explain "undermining" effects); and biased metareviews (studies with possible floor effects excluded, but those with possible ceiling effects included). Perhaps the greatest error with the undermining theory, however, is that it does not adequately recognize the multifaceted nature of intrinsic motivation (Reiss, 2004a). Advice to limit the use of applied behavior analysis based on "hidden" undermining effects is ideologically inspired and is unsupported by credible scientific evidence.

  17. Human Health Effects of Trichloroethylene: Key Findings and Scientific Issues

    Science.gov (United States)

    Jinot, Jennifer; Scott, Cheryl Siegel; Makris, Susan L.; Cooper, Glinda S.; Dzubow, Rebecca C.; Bale, Ambuja S.; Evans, Marina V.; Guyton, Kathryn Z.; Keshava, Nagalakshmi; Lipscomb, John C.; Barone, Stanley; Fox, John F.; Gwinn, Maureen R.; Schaum, John; Caldwell, Jane C.

    2012-01-01

    Background: In support of the Integrated Risk Information System (IRIS), the U.S. Environmental Protection Agency (EPA) completed a toxicological review of trichloroethylene (TCE) in September 2011, which was the result of an effort spanning > 20 years. Objectives: We summarized the key findings and scientific issues regarding the human health effects of TCE in the U.S. EPA’s toxicological review. Methods: In this assessment we synthesized and characterized thousands of epidemiologic, experimental animal, and mechanistic studies, and addressed several key scientific issues through modeling of TCE toxicokinetics, meta-analyses of epidemiologic studies, and analyses of mechanistic data. Discussion: Toxicokinetic modeling aided in characterizing the toxicological role of the complex metabolism and multiple metabolites of TCE. Meta-analyses of the epidemiologic data strongly supported the conclusions that TCE causes kidney cancer in humans and that TCE may also cause liver cancer and non-Hodgkin lymphoma. Mechanistic analyses support a key role for mutagenicity in TCE-induced kidney carcinogenicity. Recent evidence from studies in both humans and experimental animals point to the involvement of TCE exposure in autoimmune disease and hypersensitivity. Recent avian and in vitro mechanistic studies provided biological plausibility that TCE plays a role in developmental cardiac toxicity, the subject of substantial debate due to mixed results from epidemiologic and rodent studies. Conclusions: TCE is carcinogenic to humans by all routes of exposure and poses a potential human health hazard for noncancer toxicity to the central nervous system, kidney, liver, immune system, male reproductive system, and the developing embryo/fetus. PMID:23249866

  18. Scientific misconduct: also an issue in nursing science?

    NARCIS (Netherlands)

    Fierz, K.; Gennaro, S.; Dierickx, K.; Achterberg, T. van; Morin, K.H.; Geest, S. de

    2014-01-01

    PURPOSE: Scientific misconduct (SMC) is an increasing concern in nursing science. This article discusses the prevalence of SMC, risk factors and correlates of scientific misconduct in nursing science, and highlights interventional approaches to foster good scientific conduct. METHODS: Using the

  19. An overview of chemical straightening of human hair: technical aspects, potential risks to hair fibre and health and legal issues.

    Science.gov (United States)

    Miranda-Vilela, A L; Botelho, A J; Muehlmann, L A

    2014-02-01

    Personal image, as it relates to external beauty, has attracted much attention from the cosmetic industry, and capillary aesthetics is a leader in consumption in this area. There is a great diversity of products targeting both the treatment and beautification of hair. Among them, hair straighteners stand out with a high demand by costumers aiming at beauty, social acceptance and ease of daily hair maintenance. However, this kind of treatment affects the chemical structure of keratin and of the hair fibre, bringing up some safety concerns. Moreover, the development of hair is a dynamic and cyclic process, where the duration of growth cycles depends not only on where hair grows, but also on issues such as the individual's age, dietary habits and hormonal factors. Thus, although hair fibres are composed of dead epidermal cells, when they emerge from the scalp, there is a huge variation in natural wave and the response to hair cosmetics. Although it is possible to give the hair a cosmetically favourable appearance through the use of cosmetic products, for good results in any hair treatment, it is essential to understand the mechanisms of the process. Important information, such as the composition and structure of the hair fibres, and the composition of products and techniques available for hair straightening, must be taken into account so that the straightening process can be designed appropriately, avoiding undesirable side effects for hair fibre and for health. This review aims to address the morphology, chemical composition and molecular structure of hair fibres, as well as the products and techniques used for chemical hair relaxing, their potential risk to hair fibre and to health and the legal aspects of their use. © 2013 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  20. Students' Reasoning Processes in Making Decisions about an Authentic, Local Socio-Scientific Issue: Bat Conservation

    Science.gov (United States)

    Lee, Yeung Chung; Grace, Marcus

    2010-01-01

    Education for scientific literacy entails the development of scientific knowledge and the ability to apply this knowledge and value judgments to decisions about real-life issues. This paper reports an attempt to involve secondary level biology students in making decisions about an authentic socio-scientific issue--that of bat conservation--through…

  1. Scientific misconduct: also an issue in nursing science?

    NARCIS (Netherlands)

    Fierz, K.; Gennaro, S.; Dierickx, K.; Achterberg, T. van; Morin, K.H.; Geest, S. de

    2014-01-01

    PURPOSE: Scientific misconduct (SMC) is an increasing concern in nursing science. This article discusses the prevalence of SMC, risk factors and correlates of scientific misconduct in nursing science, and highlights interventional approaches to foster good scientific conduct. METHODS: Using the "Fos

  2. Scientific misconduct: also an issue in nursing science?

    Science.gov (United States)

    Fierz, Katharina; Gennaro, Susan; Dierickx, Kris; Van Achterberg, Theo; Morin, Karen H; De Geest, Sabina

    2014-07-01

    Scientific misconduct (SMC) is an increasing concern in nursing science. This article discusses the prevalence of SMC, risk factors and correlates of scientific misconduct in nursing science, and highlights interventional approaches to foster good scientific conduct. Using the "Fostering Research Integrity in Europe" report of the European Science Foundation as a framework, we reviewed the literature in research integrity promotion. Although little empirical data exist regarding prevalence of scientific misconduct in the field of nursing science, available evidence suggests a similar prevalence as elsewhere. In studies of prospective graduate nurses, 4% to 17% admit data falsification or fabrication, while 8.8% to 26.4% report plagiarizing material. Risk factors for SMC exist at the macro, meso, and micro levels of the research system. Intervention research on preventing scientific misconduct in nursing is limited, yet findings from the wider field of medicine and allied health professions suggest that honor codes, training programs, and clearly communicated misconduct control mechanisms and misconduct consequences improve ethical behavior. Scientific misconduct is a multilevel phenomenon. Interventions to decrease scientific misconduct must therefore target every level of the nursing research systems. Scientific misconduct not only compromises scientific integrity by distorting empirical evidence, but it might endanger patients. Because nurses are involved in clinical research, raising their awareness of scientifically inappropriate behavior is essential. © 2014 Sigma Theta Tau International.

  3. Dealing with scientific integrity issues: the Spanish experience.

    Science.gov (United States)

    Puigdomènech, Pere

    2014-02-01

    Integrity has been an important matter of concern for the scientific community as it affects the basis of its activities. Most countries having a significant scientific activity have dealt with this problem by different means, including drafting specific legal or soft law regulations and the appointment of stable or ad hoc committees that take care of these questions. This has also been the case in Spain. After the period of transition between dictatorship to a democratic regime, and, particularly, after the entrance in the European Union, scientific activity has increased in the country. As it could be expected, problems of misconduct have appeared and different institutions have been dealing with these matters. One of the best examples is that of Consejo Superior de Investigaciones Cientificas (CSIC), the largest institution devoted to scientific research belonging to the Spanish Government. The experience of the CSIC’s Ethics Committee in dealing with conflicts related to scientific practices is discussed here.

  4. SCIENTIFIC AUTHORSHIP, PART I: A WINDOW INOT SCIENTIFIC FRAUD SCIENTIFIC AUTHORSHIP, PART II: HISTORY, REOCCURRING ISSUES, PRACTICES, AND GUIDELINES (SEE COMMENTS)

    Science.gov (United States)

    Scientific Authorship: History, Reoccurring Issues, Practices, and Guidelines IntroductionOften, the most challenging aspect of being a scientist is dealing with the intricacies of publishing one's research and knowledge. One must do much more than just accurately record...

  5. Addressing big data issues in Scientific Data Infrastructure

    NARCIS (Netherlands)

    Demchenko, Y.; Membrey, P.; Grosso, P.; de Laat, C.; Smari, W.W.; Fox, G.C.

    2013-01-01

    Big Data are becoming a new technology focus both in science and in industry. This paper discusses the challenges that are imposed by Big Data on the modern and future Scientific Data Infrastructure (SDI). The paper discusses a nature and definition of Big Data that include such features as Volume,

  6. Addressing big data issues in Scientific Data Infrastructure

    NARCIS (Netherlands)

    Demchenko, Y.; Membrey, P.; Grosso, P.; de Laat, C.; Smari, W.W.; Fox, G.C.

    2013-01-01

    Big Data are becoming a new technology focus both in science and in industry. This paper discusses the challenges that are imposed by Big Data on the modern and future Scientific Data Infrastructure (SDI). The paper discusses a nature and definition of Big Data that include such features as Volume,

  7. Modeling Scientific Research Articles – Shifting Perspectives and Persistent Issues

    NARCIS (Netherlands)

    De Waard, Anita; Kircz, Joost

    2008-01-01

    We review over 10 years of research at Elsevier and various Dutch academic institutions on establishing a new format for the scientific research article. Our work rests on two main theoretical principles: the concept of modular documents, consisting of content elements that can exist and be publishe

  8. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of a health claim related to sugar beet fibre and increasing faecal bulk pursuant to Article 13(5) of Regulation (EC) No 1924/2006

    DEFF Research Database (Denmark)

    Tetens, Inge

    based on newly developed scientific evidence related to sugar beet fibre and “increasing faecal bulk”. The food constituent that is the subject of the health claim is sugar beet fibre. The Panel considers that sugar beet fibre is sufficiently characterised in relation to the claimed effect. The claimed......Following an application from Nordic Sugar A/S, submitted pursuant to Article 13(5) of Regulation (EC) No 1924/2006 via the Competent Authority of Denmark, the Panel on Dietetic Products, Nutrition and Allergies was asked to deliver an opinion on the scientific substantiation of a health claim...... that a cause and effect relationship has been established between the consumption of sugar beet fibre and increasing faecal bulk. The following wording reflects the scientific evidence: “Sugar beet fibre increases faecal bulk”. In order to bear the claim a food should be at least “high in fibre” as per...

  9. Extrinsic and Intrinsic Motivation at 30: Unresolved Scientific Issues

    Science.gov (United States)

    Reiss, Steven

    2005-01-01

    The undermining effect of extrinsic reward on intrinsic motivation remains unproven. The key unresolved issues are construct invalidity (all four definitions are unproved and two are illogical); measurement unreliability (the free-choice measure requires unreliable, subjective judgments to infer intrinsic motivation); inadequate experimental…

  10. Extrinsic and Intrinsic Motivation at 30: Unresolved Scientific Issues

    Science.gov (United States)

    Reiss, Steven

    2005-01-01

    The undermining effect of extrinsic reward on intrinsic motivation remains unproven. The key unresolved issues are construct invalidity (all four definitions are unproved and two are illogical); measurement unreliability (the free-choice measure requires unreliable, subjective judgments to infer intrinsic motivation); inadequate experimental…

  11. Scientific integrity: critical issues in environmental health research

    Directory of Open Access Journals (Sweden)

    Merlo Domenico

    2008-01-01

    Full Text Available Abstract Environmental health research is a relatively new scientific area with much interdisciplinary collaboration. Regardless of which human population is included in field studies (e.g., general population, working population, children, elderly, vulnerable sub-groups, etc. their conduct must guarantee well acknowledged ethical principles. These principles, along with codes of conduct, are aimed at protecting study participants from research-related undesired effects and guarantee research integrity. A central role is attributed to the need for informing potential participants (i.e., recruited subjects who may be enrolled in a study, obtaining their written informed consent to participate, and making them aware of their right to refuse to participate at any time and for any reason. Data protection is also required and communication of study findings must respect participant's willingness to know or not know. This is specifically relevant for studies including biological markers and/or storing biological samples that might be analysed years later to tackle research objectives that were specified and communicated to participants at the time of recruitment or that may be formulated after consent was obtained. Integrity is central to environmental health research searching for causal relations. It requires open communication and trust and any violation (i.e., research misconduct, including fabrication or falsification of data, plagiarism, conflicting interests, etc. may endanger the societal trust in the research community as well as jeopardize participation rates in field projects.

  12. Scientific integrity: critical issues in environmental health research.

    Science.gov (United States)

    Merlo, Domenico Franco; Vahakangas, Kirsi; Knudsen, Lisbeth E

    2008-06-05

    Environmental health research is a relatively new scientific area with much interdisciplinary collaboration. Regardless of which human population is included in field studies (e.g., general population, working population, children, elderly, vulnerable sub-groups, etc.) their conduct must guarantee well acknowledged ethical principles. These principles, along with codes of conduct, are aimed at protecting study participants from research-related undesired effects and guarantee research integrity. A central role is attributed to the need for informing potential participants (i.e., recruited subjects who may be enrolled in a study), obtaining their written informed consent to participate, and making them aware of their right to refuse to participate at any time and for any reason. Data protection is also required and communication of study findings must respect participant's willingness to know or not know. This is specifically relevant for studies including biological markers and/or storing biological samples that might be analysed years later to tackle research objectives that were specified and communicated to participants at the time of recruitment or that may be formulated after consent was obtained.Integrity is central to environmental health research searching for causal relations. It requires open communication and trust and any violation (i.e., research misconduct, including fabrication or falsification of data, plagiarism, conflicting interests, etc.) may endanger the societal trust in the research community as well as jeopardize participation rates in field projects.

  13. Climate Change and Everyday Life: Repertoires Children Use to Negotiate a Socio-Scientific Issue

    Science.gov (United States)

    Byrne, Jenny; Ideland, Malin; Malmberg, Claes; Grace, Marcus

    2014-01-01

    There are only a few studies about how primary school students engage in socio-scientific discussions. This study aims to add to this field of research by focusing on how 9-10-year-olds in Sweden and England handle climate change as a complex environmental socio-scientific issue (SSI), within the context of their own lives and in relation to…

  14. Science Teachers' Use of Mass Media to Address Socio-Scientific and Sustainability Issues

    Science.gov (United States)

    Klosterman, Michelle L.; Sadler, Troy D.; Brown, Julie

    2012-01-01

    The currency, relevancy and changing nature of science makes it a natural topic of focus for mass media outlets. Science teachers and students can capitalize on this wealth of scientific information to explore socio-scientific and sustainability issues; however, without a lens on how those media are created and how representations of science are…

  15. The Effect of Using Socio-Scientific Issues Approach in Teaching Environmental Issues on Improving the Students' Ability of Making Appropriate Decisions towards These Issues

    Science.gov (United States)

    Zo'bi, Abdallah Salim

    2014-01-01

    This study aimed to identify nature of students' decisions patterns towards environmental issues and the possibility to improve these decisions during teaching process using Socio-Scientific Issues Approach. And to achieve this, the researcher prepared and developed tools of the study represented by a test of open questions focused on…

  16. Challenges Faced by Teachers Implementing Socio-Scientific Issues as Core Elements in Their Classroom Practices

    Science.gov (United States)

    Bossér, Ulrika; Lundin, Mattias; Lindahl, Mats; Linder, Cedric

    2015-01-01

    Teachers may face considerable challenges when implementing socio-scientific issues (SSI) in their classroom practices, such as incorporating student-centred teaching practices and exploring knowledge and values in the context of socioscientific issues. This year-long study explores teachers' reflections on the process of developing their…

  17. A Framework for Teachers' Assessment of Socio-Scientific Argumentation: An Example Using the GMO Issue

    Science.gov (United States)

    Christenson, Nina; Chang Rundgren, Shu-Nu

    2015-01-01

    Socio-scientific issues (SSI) have proven to be suitable contexts for students to actively reflect on and argue about complex social issues related to science. Research has indicated that explicitly teaching SSI argumentation is a good way to help students develop their argumentation skills and make them aware of the complexity of SSI. However,…

  18. How Students' Values Are Intertwined with Decisions in a Socio-Scientific Issue

    Science.gov (United States)

    Paraskeva-Hadjichambi, Demetra; Hadjichambis, Andreas Ch.; Korfiatis, Konstantinos

    2015-01-01

    The present study incorporated a scaffolding decision making procedure on an authentic environmental socio-scientific issue and investigated how students' decisions are intertwined with their values. Computer-based activities provided necessary information and allowed for the consideration of multiple aspects of the issue, the study of the effects…

  19. A Framework for Teachers' Assessment of Socio-Scientific Argumentation: An Example Using the GMO Issue

    Science.gov (United States)

    Christenson, Nina; Chang Rundgren, Shu-Nu

    2015-01-01

    Socio-scientific issues (SSI) have proven to be suitable contexts for students to actively reflect on and argue about complex social issues related to science. Research has indicated that explicitly teaching SSI argumentation is a good way to help students develop their argumentation skills and make them aware of the complexity of SSI. However,…

  20. Socioscientific Issues: A Path Towards Advanced Scientific Literacy and Improved Conceptual Understanding of Socially Controversial Scientific Theories

    Science.gov (United States)

    Pinzino, Dean William

    This thesis investigates the use of socioscientific issues (SSI) in the high school science classroom as an introduction to argumentation and socioscientific reasoning, with the goal of improving students' scientific literacy (SL). Current research is reviewed that supports the likelihood of students developing a greater conceptual understanding of scientific theories as well as a deeper understanding of the nature of science (NOS), through participation in informal and formal forms of argumentation in the context of SSI. Significant gains in such understanding may improve a student's ability to recognize the rigor, legitimacy, and veracity of scientific claims and better discern science from pseudoscience. Furthermore, students that participate in significant SSI instruction by negotiating a range of science-related social issues can make significant gains in content knowledge and develop the life-long skills of argumentation and evidence-based reasoning, goals not possible in traditional lecture-based science instruction. SSI-based instruction may therefore help students become responsible citizens. This synthesis also suggests that that the improvements in science literacy and NOS understanding that develop from sustained engagement in SSI-based instruction will better prepare students to examine and scrutinize socially controversial scientific theories (i.e., evolution, global warming, and the Big Bang).

  1. EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA); Scientific Opinion on Dietary Reference Values for carbohydrates and dietary fibre

    DEFF Research Database (Denmark)

    Tetens, Inge

    but will depend on the amount of fat and protein ingested. The Panel proposes 45 to 60 E% as the reference Intake range for carbohydrates applicable to both adults and children older than one year of age. Although high frequency of intake of sugar-containing foods can increase the risk of dental caries......, there are insufficient data to set an upper limit for (added) sugar intake. Based on the available evidence on bowel function, the Panel considers dietary fibre intakes of 25 g/day to be adequate for normal laxation in adults. A fibre intake of 2 g/MJ is considered adequate for normal laxation in children from the age...

  2. Patterns in Students' Argumentation Confronted with a Risk-focused Socio-scientific Issue

    Science.gov (United States)

    Kolstø, Stein Dankert

    2006-11-01

    This paper reports a qualitative study on students’ informal reasoning on a controversial socio-scientific issue. Twenty-two students from four science classes in Norway were interviewed about the local construction of new power lines and the possible increased risk of childhood leukaemia. The focus in the study is on what arguments the students employ when asked about their decision-making and the interplay between knowledge and personal values. Five different types of main arguments are identified: the relative risk argument, the precautionary argument, the uncertainty argument, the small risk argument, and the pros and cons argument. These arguments are presented through case studies, and crucial information and values are identified for each argument. The students made use of a range of both scientific and non-scientific knowledge. The findings are discussed in relation to possible consequences for teaching models aimed at increasing students’ ability to make thoughtful decisions on socio-scientific issues.

  3. Positive Emotional Responses to Hybridised Writing about a Socio-Scientific Issue

    Science.gov (United States)

    Tomas, Louisa; Ritchie, Stephen M.

    2012-01-01

    In order to understand better the role of affect in learning about socio-scientific issues (SSI), this study investigated Year 12 students' emotional arousal as they participated in an online writing-to-learn science project about the socio-scientific issue of biosecurity. Students wrote a series of hybridised scientific narratives, or BioStories, that integrate scientific information about biosecurity with narrative storylines, and uploaded these to a dedicated website. Throughout their participation in the project, students recorded their emotional responses to the various activities ( N = 50). Four case students were also video recorded during selected science lessons as they researched, composed and uploaded their BioStories for peer review. Analysis of these data, as well as interview data obtained from the case students, revealed that pride, strength, determination, interest and alertness were among the positive emotions most strongly elicited by the project. These emotions reflected students' interest in learning about a new socio-scientific issue, and their enhanced feelings of self-efficacy in successfully writing hybridised scientific narratives in science. The results of this study suggest that the elicitation of positive emotional responses as students engage in hybridised writing about SSI with strong links to environmental education, such as biosecurity, can be valuable in engaging students in education for sustainability.

  4. Policy Statements Issued by Scientific Societies: Why Less can be More

    Science.gov (United States)

    Folger, P. F.

    2001-12-01

    The results of hydrological research are increasingly important to decision-makers grappling with problems as diverse as global climate change, non-point source pollution, extreme weather events, and damage from flooding. In some cases scientific aspects of these problems are interwoven with economic, political and social disputes, and policy makers often seek the consensus scientific opinion to help shape the debate. Policy or position statements issued by scientific societies like AGU can embody scientific consensus and thus inform the public and policy makers. But this is not always the case. The potential for creating public misunderstanding is ever present. Therefore, the process leading to a policy statement needs to be deliberative, inclusive to the extent possible, and circumspect. In contrast to advocacy organizations or trade groups, as a learned society AGU and members acting on its behalf should only advocate positions on political or social issues that are based solely on available geophysical data and recognized scientific debate. That does not mean that AGU and other scientific societies must refrain from entering a political debate. AGU has a responsibility to its members to adopt positions of advocacy on geophysical science issues based on their intrinsic merits and needs. However, a learned society like AGU should state only what is credible about the scientific aspects of a political debate and not overstep its authority as an objective source of analysis and commentary for the geophysical sciences. Before adopting an advocacy position, AGU's volunteers follow a process that includes checks and balances so that the final statement is based on sound scientific issues and reflects the interests of the Union as a whole. Any AGU member or committee can propose a position statement, but the Committee on Public Affairs (COPA) decides whether the proposal fall within the guidelines for advocacy. If it does and if COPA considers the issue worthy of an

  5. Scientific Literacy, Environmental Issues, and PISA 2006: The 2008 Paul F-Brandwein Lecture

    Science.gov (United States)

    Bybee, Rodger W.

    2008-12-01

    In today's world, scientific literacy has become essential to full participation of citizens. Certainly, important components of scientific literacy include resource use and environmental quality. The 2006 Program for International Student Assessment (PISA) centered on scientific literacy and included resources and environments as two contexts for the test and student questionnaire. The article first introduces PISA 2006, and then provides a general overview of results. Using two released units from PISA 2006, I then turn to results and a discussion of students' science competencies and attitudes relative to environmental and resources issues. The article concludes with a discussion of educational policies for science education programs and teaching practices.

  6. Students' Argumentation Skills across Two Socio-Scientific Issues in a Confucian Classroom: Is Transfer possible?

    Science.gov (United States)

    Foong, Chan-Choong; Daniel, Esther G. S.

    2013-01-01

    This paper argues the possible simultaneous development and transfer of students' argumentation skills from one socio-scientific issue to another in a Confucian classroom. In Malaysia, the Chinese vernacular schools follow a strict Confucian philosophy in the teaching and learning process. The teacher talks and the students listen. This case study…

  7. Teachers' Experience of Working with Socio-Scientific Issues: A Large Scale and in Depth Study

    Science.gov (United States)

    Ekborg, Margareta; Ottander, Christina; Silfver, Eva; Simon, Shirley

    2013-01-01

    The research is an investigation of teachers' experience of working with socio-scientific issues (SSI). A large group of teachers (55) chose one of six cases with the characteristics of SSI and were free to organize the work as they found appropriate. The research focuses on how teachers chose content, organized their work and experienced the…

  8. Cross Cultural Exchange to Support Reasoning about Socio-Scientific Sustainability Issues

    Science.gov (United States)

    Morin, Olivier; Tytler, Russell; Barraza, Laura; Simonneaux, Laurence; Simonneaux, Jean

    2013-01-01

    In this article, we describe a project on reasoning about socio-scientific issues (SSIs), involving French and Australian pre-service science teachers engaged in on-line discussion and development of a wiki. In the research, we developed frameworks for looking at the quality of reasoning about "socially acute" sustainability questions.…

  9. Science Theatre at School: Providing a context to learn about socio-scientific issues

    NARCIS (Netherlands)

    Wieringa, N.F.; Swart, J.A.A.; Maples, T.; Witmondt, L.; Tobi, H.; Windt, v.d. H.J.

    2011-01-01

    Science theatre is recognised as a method for teaching socio-scientific issues (SSI), but is largely under-researched. The essence of science theatre at school is to shape a contextualisation for science and technology and its relationships to individuals and society at large, with the aim to trigge

  10. Students' Argumentation Skills across Two Socio-Scientific Issues in a Confucian Classroom: Is transfer possible?

    Science.gov (United States)

    Foong, Chan-Choong; Daniel, Esther G. S.

    2013-09-01

    This paper argues the possible simultaneous development and transfer of students' argumentation skills from one socio-scientific issue to another in a Confucian classroom. In Malaysia, the Chinese vernacular schools follow a strict Confucian philosophy in the teaching and learning process. The teacher talks and the students listen. This case study explored the transfer of argumentation skills across two socio-scientific issues in such a Form 2 (8th grade) classroom. An instructional support to complement the syllabus was utilised. The teaching approach in the instructional support was more constructivist in nature and designed to introduce argumentation skills which is uncommon in a Confucian classroom. The two socio-scientific issues were genetically modified foods and deforestation. This paper presents a part of the bigger case study that was conducted. Data collected from written arguments were analysed using an analytical framework built upon Toulmin's ideas. The whole class analysis indicated progression in students' argumentation skills in their ability to give more valid grounds and rebuttals during the transfer. The individual analysis suggests progression in the majority of students' performance, while several students demonstrated non-progression when they faced a different socio-scientific issue.

  11. Teaching with Socio-Scientific Issues in Physical Science: Teacher and Students' Experiences

    Science.gov (United States)

    Talens, Joy

    2016-01-01

    Socio-scientific issues (SSI) are recommended by many science educators worldwide for learners to acquire first hand experience to apply what they learned in class. This investigated experiences of teacher-researcher and students in using SSI in Physical Science, Second Semester, School Year 2012-2013. Latest and controversial news articles on…

  12. Progression in Ethical Reasoning When Addressing Socio-Scientific Issues in Biotechnology

    Science.gov (United States)

    Berne, Birgitta

    2014-01-01

    This article reports on the outcomes of an intervention in a Swedish school in which the author, a teacher-researcher, sought to develop students' (14-15 years old) ethical reasoning in science through the use of peer discussions about socio-scientific issues. Prior to the student discussions various prompts were used to highlight different…

  13. Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of a health claim related to sugar beet fibre and decreasing intestinal transit time pursuant to Article 13(5) of Regulation (EC) No 1924/2006

    DEFF Research Database (Denmark)

    Tetens, Inge

    Following an application from Nordic Sugar A/S, submitted pursuant to Article 13(5) of Regulation (EC) No 1924/2006 via the Competent Authority of Denmark, the Panel on Dietetic Products, Nutrition and Allergies was asked to deliver an opinion on the scientific substantiation of a health claim...... based on newly developed scientific evidence related to sugar beet fibre and “decreasing intestinal transit time”. The food constituent that is the subject of the health claim is sugar beet fibre. This opinion applies to sugar beet fibre naturally present in foods and to those forms added to foods...... that decreasing intestinal (orofaecal) transit time may be a beneficial physiological effect. The applicant provided four human studies as pertinent to the health claim. The Panel considers that no conclusion can be drawn from three studies for the scientific substantiation of the claim owing to methodological...

  14. Teacher formation related to socio-scientific issues: complexity, contributions and limitations of an educational practice

    Directory of Open Access Journals (Sweden)

    Mariuce Campos de Moraes

    2015-12-01

    Full Text Available This reflection refers to teacher formation related to socio-scientific issues. Whereas such matters take into account the impact of scientific development in society, including ethical aspects and encompass dilemmas involving a wide range of prospects for its resolution, we propose analysis of the complexity that is inherent in their teaching. Thus, we aimed to analyze different spaces and teaching time that produce and are produced in close linkage between theory and practice, as well as their contributions and limitations. The study required a dynamic conversation system that led to the analysis indicators. The issue of sustainability was shown to be feasible for educational planning as cover technical and scientific knowledge, ethical, social and economic pressures. The collective production allowed understand arguments and reflective-creative processes. The lived relations in schools has accompanied and limited the ideas expressed on the socio-scientific issues. We understand that the simultaneity of research and reflection in the sociocultural context has strengthened teacher formation.

  15. When Scientific Knowledge, Daily Life Experience, Epistemological and Social Considerations Intersect: Students' Argumentation in Group Discussions on a Socio-scientific Issue

    Science.gov (United States)

    Albe, Virginie

    2008-01-01

    Socio-scientific issues in class have been proposed in an effort to democratise science in society. A micro-ethnographic approach has been used to explore how students elaborate arguments on a socio-scientific controversy in the context of small group discussions. Several processes of group argumentation have been identified. Students’ arguments were elaborated from scientific data, common ideas and epistemological and strategic considerations. Students’ social interactions influenced the patterns of argumentation elaborated within the group discussions. Implications of this study for the teaching of socio-scientific issues in class are discussed.

  16. Learning as change: Responding to socio-scientific issues through informal education

    Science.gov (United States)

    Allen, Lauren Brooks

    Informal learning is an important venue for educating the general public about complex socio-scientific issues: intersections of scientific understanding and society. My dissertation is a multi-tiered analysis of how informal education, and particularly informal educators, can leverage learning to respond to one particular socio-scientific issue: climate change. Life-long, life-wide, and life-deep learning not only about the science of climate change, but how communities and society as a whole can respond to it in ways that are commensurate with its scale are necessary. In my three-article dissertation, I investigated the changes in practice and learning that informal educators from a natural history museum underwent in the process of implementing a new type of field trip about climate change. This study focused on inquiry-based learning principles taken on by the museum educators, albeit in different ways: learner autonomy, conversation, and deep investigation. My second article, a short literature review, makes the argument that climate change education must have goals beyond simply increasing learners' knowledge of climate science, and proposes three research-based principles for such learning: participation, relevance, and interconnectedness. These principles are argued to promote learning to respond to climate change as well as increased collective efficacy, necessary for responding. Finally, my third article is an in-depth examination of a heterogeneous network of informal educators and environmental professionals who worked together to design and implement a city-wide platform for informal climate change learning. By conceptualizing climate change learning at the level of the learning ecology, educators and learners are able to see how it can be responded to at the community level, and understand how climate change is interconnected with other scientific, natural, and social systems. I briefly discuss a different socio-scientific issue to which these

  17. When Scientific Knowledge, Daily Life Experience, Epistemological and Social Considerations Intersect: Students' Argumentation in Group Discussions on a Socio-Scientific Issue

    Science.gov (United States)

    Albe, Virginie

    2008-01-01

    Socio-scientific issues in class have been proposed in an effort to democratise science in society. A micro-ethnographic approach has been used to explore how students elaborate arguments on a socio-scientific controversy in the context of small group discussions. Several processes of group argumentation have been identified. Students' arguments…

  18. Debate on global warming as a socio-scientific issue: science teaching towards political literacy

    Science.gov (United States)

    dos Santos, Wildson Luiz Pereira

    2014-09-01

    The focus of this response to the original article by Tom G. H. Bryce and Stephen P. Day (Cult Stud Sci Educ. doi: 10.1007/s11422-012-9407-1, 2013) is the use of empirical data to illustrate and expand the understanding of key points of their argument. Initially, I seek to discuss possible answers to the three questions posed by the authors related to: (1) the concerns to be addressed and the scientific knowledge to be taken into account in the climate change debate, (2) the attention to be paid to perspectives taken by "alarmists" and "deniers," and (3) the approaches to be used to conduct controversial global warming debate. In this discussion, I seek to contribute to the debate proposed by the original paper, illustrating various points commented on by the authors and expanding to other possibilities, which highlight the importance of political issues in the debate. Therefore, I argue that socio-political issues must be taken into account when I aim for a scientific literacy that can enhance students' political education. Likewise, I extend the debate presented in the original article, emphasizing the attention that should be paid to these aspects and approaching science education from a critical perspective. Highlighting only the confirmation bias without considering political implications of the debate can induce a reductionist and empiricist view of science, detached from the political power that acts on scientific activity. In conclusion, I support the idea that for a critical science education, the discussion of political issues should be involved in any controversial debate, a view, which goes beyond the confirmation bias proposed by Bryce and Day for the global warming debate. These issues are indeed vital and science teachers should take them into account when preparing their lessons for the debate on climate change.

  19. Issues concerning scientific production of including people with disabilities at work.

    Science.gov (United States)

    Guimarães, B M; Martins, L B; Barkokébas Junior, B

    2012-01-01

    This article presents the results of a survey carried out on leading periodicals in the areas of Ergonomics, Physiotherapy and Occupational Therapy, the aim of which was to identify scientific publications on the inclusion at work of people with disabilities. The survey of articles published on this topic in the following journals was conducted in December 2010: Applied Ergonomics, Ergonomics, the International Journal of Industrial Ergonomics, Disability and Rehabilitation, and the Journal of Occupational Rehabilitation. The survey covered issues published between 2000 and 2010 and was conducted electronically using the CAPES Periodicals Portal. To collect the articles, it was necessary to check the articles published in each of the issues of each volume of these periodicals. This is how the articles on the topic in question were found. There were 27 articles on the topic of inclusion at work of people with disabilities, of which 13 were published in the Journal of Occupational Rehabilitation and 12 in Disability and Rehabilitation. Thus, it is clear that the issue in question is still a subject that is seldom dealt with in these publications and it is noted that only two articles were published in Ergonomics journals in this period, thus confirming the paucity of scientific publications on this subject.

  20. Progression in Ethical Reasoning When Addressing Socio-scientific Issues in Biotechnology

    Science.gov (United States)

    Berne, Birgitta

    2014-11-01

    This article reports on the outcomes of an intervention in a Swedish school in which the author, a teacher-researcher, sought to develop students' (14-15 years old) ethical reasoning in science through the use of peer discussions about socio-scientific issues. Prior to the student discussions various prompts were used to highlight different aspects of the issues. In addition, students were given time to search for further information themselves. Analysis of students' written arguments, from the beginning of the intervention and afterwards, suggests that many students seem to be moving away from their use of everyday language towards using scientific concepts in their arguments. In addition, they moved from considering cloning and 'designer babies' solely in terms of the present to considering them in terms of the future. Furthermore, the students started to approach the issues in additional ways using not only consequentialism but also the approaches of virtue ethics, and rights and duties. Students' progression in ethical reasoning could be related to the characteristics of the interactions in peer discussions as students who critically and constructively argued with each other's ideas, and challenged each other's claims, made progress in more aspects of ethical reasoning than students merely using cumulative talk. As such, the work provides valuable indications for the importance of introducing peer discussions and debates about SSIs in connection to biotechnology into the teaching of science in schools.

  1. XI Scientific Conference Selected Issues of Electrical Engineering and Electronics (WZEE)

    CERN Document Server

    Mazur, Damian; Analysis and Simulation of Electrical and Computer Systems

    2015-01-01

    This book presents the selected results of the XI Scientific Conference Selected Issues of Electrical Engineering and Electronics (WZEE) which was held in Rzeszów and Czarna, Poland on September 27-30, 2013. The main aim of the Conference was to provide academia and industry to discuss and present the latest technological advantages and research results and to integrate the new interdisciplinary scientific circle in the field of electrical engineering, electronics and mechatronics. The Conference was organized by the Rzeszów Division of Polish Association of Theoretical and Applied Electrical Engineering (PTETiS) in cooperation with Rzeszów University of Technology, the Faculty of Electrical and Computer Engineering and Rzeszów University, the Faculty of Mathematics and Natural Sciences.  

  2. "It's Still Science but Not Like Normal Science": Girls' Responses to the Teaching of Socio-Scientific Issues

    Science.gov (United States)

    Morris, Helen

    2014-01-01

    Socio-scientific issues, which are often controversial, involve the use of science and are of interest to society, raising ethical and moral dilemmas. Examples of these issues could include genetic technology or air pollution. Following a curriculum reform in England in 2006, socioscientific issues now have a heightened presence in the 14-16…

  3. Reflecting Socio-Scientific Issues for Science Education Coming from the Case of Curriculum Development on Doping in Chemistry Education

    Science.gov (United States)

    Stolz, Miriam; Witteck, Torsten; Marks, Ralf; Eilks, Ingo

    2013-01-01

    Socio-scientific issue-based science education has been suggested for promoting general educational skills development in science classes. However, there is a lack of operationalized criteria, which can be used to reflect upon societal issues to whether turning them into issues for science classroom instruction. This paper describes a case study…

  4. Wikipedia as Open Science: non-expert involvement in controversial scientific issues

    OpenAIRE

    Aibar Puentes, Eduard; Lerga Felip, Maura

    2016-01-01

    This study considers Wikipedia as a sui generis instance of Open Science and analyses how the non-expert or lay character of the average Wikipedia editor and the open and collaborative model of this free encyclopaedia are actually shaping the way controversial scientific issues are presented. Aquest estudi considera la Viquipèdia com un exemple sui generis de la ciència oberta, i analitza cóm el no expert o el caràcter laic de l'editor de Viquipèdia i el model col·laboratiu i obert d'aques...

  5. Text-based plagiarism in scientific publishing: issues, developments and education.

    Science.gov (United States)

    Li, Yongyan

    2013-09-01

    Text-based plagiarism, or copying language from sources, has recently become an issue of growing concern in scientific publishing. Use of CrossCheck (a computational text-matching tool) by journals has sometimes exposed an unexpected amount of textual similarity between submissions and databases of scholarly literature. In this paper I provide an overview of the relevant literature, to examine how journal gatekeepers perceive textual appropriation, and how automated plagiarism-screening tools have been developed to detect text matching, with the technique now available for self-check of manuscripts before submission; I also discuss issues around English as an additional language (EAL) authors and in particular EAL novices being the typical offenders of textual borrowing. The final section of the paper proposes a few educational directions to take in tackling text-based plagiarism, highlighting the roles of the publishing industry, senior authors and English for academic purposes professionals.

  6. On defining dietary fibre.

    Science.gov (United States)

    DeVries, Jonathan W

    2003-02-01

    Establishing a definition for dietary fibre has historically been a balance between nutrition knowledge and analytical method capabilities. While the most widely accepted physiologically-based definitions have generally been accurate in defining the dietary fibre in foods, scientists and regulators have tended, in practice, to rely on analytical procedures as the definitional basis in fact. As a result, incongruities between theory and practice have resulted in confusion regarding the components that make up dietary fibre. In November 1998 the president of the American Association of Cereal Chemists (AACC) appointed an expert scientific review committee and charged it with the task of reviewing and, if necessary, updating the definition of dietary fibre. The committee was further charged with assessing the state of analytical methodology and making recommendations relevant to the updated definition. After due deliberation, an updated definition of dietary fibre was delivered to the AACC Board of Directors for consideration and adoption (Anon, 2000; Jones 2000b). The updated definition includes the same food components as the historical working definition used for approximately 30 years (a very important point, considering that the majority of the research of the past 30 years delineating the positive health effects of dietary fibre is based on that working definition). However, the updated definition more clearly delineates the make-up of dietary fibre and its physiological functionality. As a result, relatively few changes will be necessary in analytical methodology. Current methodologies, in particular AACC-approved method of analysis 32-05 (Grami, 2000), Association of Official Analytical Chemists' official method of analysis 985.29 (Horwitz, 2000a) or AACC 32-07 (Grami, 2000) Association of Official Analytical Chemists 991.43 (Horwitz, 2000a) will continue to be sufficient and used for most foods. A small number of additional methods will be necessary to

  7. Students' Participation in an Interdisciplinary, Socioscientific Issues Based Undergraduate Human Biology Major and Their Understanding of Scientific Inquiry

    Science.gov (United States)

    Eastwood, Jennifer L.; Sadler, Troy D.; Sherwood, Robert D.; Schlegel, Whitney M.

    2013-01-01

    The purpose of this study was to examine whether Socioscientific Issues (SSI) based learning environments affect university students' epistemological understanding of scientific inquiry differently from traditional science educational contexts. We identify and compare conceptions of scientific inquiry of students participating in an…

  8. Socio-Scientific Issues in Health Contexts: Treading a rugged terrain

    Science.gov (United States)

    Chung Lee, Yeung

    2012-02-01

    The science-technology-society agenda has evolved over time to meet emerging educational aims in the light of changes in society and the environment. There is increasing emphasis on students' decision-making on socio-scientific issues (SSIs) not only to highlight the intricate relationships between science, technology, society, and the environment, but also to allow students to incorporate multiple viewpoints into the development of critical reasoning and responsible citizenship. Most research emphases have been on the rationality of reasoning rather than on the internal psychological context that underpins reasoning. This paper explores how these various aspects of reasoning interact in decision-making on SSIs in health contexts through case studies of recent issues in this field. The case studies reveal the negotiation of multiple influences in addressing SSIs in health contexts and the potential interactions between the psychological processes of individuals, science, and sociocultural perspectives. A tentative model to address these interactions emerges from this explorative study and has implications for the use of health-related issues in promoting SSI education.

  9. Health issues of female foreign domestic workers: a systematic review of the scientific and gray literature.

    Science.gov (United States)

    Malhotra, Rahul; Arambepola, Chandima; Tarun, Samiksha; de Silva, Vijitha; Kishore, Jugal; Østbye, Truls

    2013-01-01

    Although the number of female foreign domestic workers (FDWs) is increasing worldwide, little is known about their health issues. To systematically review the literature on health issues of female FDWs to ascertain the problems studied, identify limitations, and suggest future research and policy implications. A systematic database (PubMed, EBSCO Host, and Google Scholar) and bibliographic search identified the English-language scientific and gray literature published during 1990-2012 addressing health issues of female FDWs living with the family of the employer, using qualitative and/or quantitative research methods. Studies in which female FDWs constituted less than half of the participants were excluded. The health issues studied and identified were adverse work conditions and associated health problems (such as physical, verbal, and sexual abuse at the workplace, caregiving tasks associated with musculoskeletal strain, and chemical exposure associated with respiratory difficulty), mental health (psychotic, neurotic, and mood disorders), infectious diseases (most of the studies were on intestinal parasitic infections), and health knowledge/attitudes/practices (most of the studies were in context of sexual and reproductive health). Most of the studies were medical record reviews or questionnaire-based surveys utilizing convenience sampling or qualitative interviews/focus group discussions. Female FDWs face numerous health problems. Studies on representative, possibly longitudinal, samples of female FDWs focusing on specific health conditions are needed to better understand the epidemiology of such conditions. Concerted efforts through the governments of both labor-sending and host countries are required to improve the health, work conditions, and safety of this vulnerable group of women.

  10. The States-of-arts and Key Scientific Issues on Durability Research of Concrete Structures

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Concrete has traditionally been regarded as a durable material requiring little or no maintenance. However, over the past several decades, a number of durability related problems have emerged and stimulated research into the factors relating to concrete durability globally. The challenge now facing practicing engineers is how to design and build structures that not only satisfy the specified structural requirements, but also achieve the performance levels required from a durability standpoint. Research works on concrete structural durability have been widely reported in the literature over the last several decades. In this paper, reviews of four stages of research work on durability, i e, environments, materials, components, and structures, were presented. Afterwards, the key scientific issues in this field were also pointed out.

  11. Scepticism and trust: two counterpoint essentials in science education for complex socio-scientific issues

    Science.gov (United States)

    Fensham, Peter J.

    2014-09-01

    In this response to Tom G. K. Bryce and Stephen P. Day's (Cult Stud Sci Educ. doi: 10.1007/s11422-013-9500-0, 2013) original article, I share with them their interest in the teaching of climate change in school science, but I widen it to include other contemporary complex socio-scientific issues that also need to be discussed. I use an alternative view of the relationship between science, technology and society, supported by evidence from both science and society, to suggest science-informed citizens as a more realistic outcome image of school science than the authors' one of mini-scientists. The intellectual independence of students Bryce and Day assume, and intend for school science, is countered with an active intellectual dependence. It is only in relation to emerging and uncertain scientific contexts that students should be taught about scepticism, but they also need to learn when, and why to trust science as an antidote to the expressions of doubting it. Some suggestions for pedagogies that could lead to these new learnings are made. The very recent fifth report of the IPCC answers many of their concerns about climate change.

  12. Some challenges and issues in managing, and preserving access to, long-lived collections of digital scientific and technical data

    Directory of Open Access Journals (Sweden)

    W L Anderson

    2006-01-01

    Full Text Available One goal of the Committee on Data for Science and Technology is to solicit information about, promote discussion of, and support action on the many issues related to scientific and technical data preservation, archiving, and access. This brief paper describes four broad categories of issues that help to organize discussion, learning, and action regarding the work needed to support the long-term preservation of, and access to, scientific and technical data. In each category, some specific issues and areas of concern are described.

  13. Investigating Socioscientific Issues via Scientific Habits of Mind: Development and Validation of the Scientific Habits of Mind Survey

    Science.gov (United States)

    Calik, Muammer; Coll, Richard Kevin

    2012-01-01

    In this paper, we describe the Scientific Habits of Mind Survey (SHOMS) developed to explore public, science teachers' and scientists' understanding of habits of mind (HoM). The instrument contained 59 items, and captures the seven SHOM identified by Gauld. The SHOM was validated by administration to two cohorts of pre-service science teachers:…

  14. Policy Issues in Accessibility and Interoperability of Scientific Data: Experiences from the Carbon Modeling Field

    Science.gov (United States)

    Kishor, P.; Peckham, S. D.; Gower, S. T.; Batzli, S.

    2010-12-01

    Large-scale terrestrial ecosystem modeling is highly parameterized, and requires lots of historical data. Routine model runs can easily utlize hundreds of Gigabytes, even Terabytes of data on tens, perhaps hundreds of parameters. It is a given that no one modeler can or does collect all the required data. All modelers depend upon other scientists, and governmental and research agencies for their data needs. This is where data accessibility and interoperability become crucial for the success of the project. Having well-documented and quality data available in a timely fashion can greatly assist a project's progress, while the converse can bring the project to a standstill, leading to a large amount of wasted staff time and resources. Data accessibility is a complex issue -- at best, it is an unscientific composite of a variety of factors: technological, legal, cultural, semantic, and economic. In reality, it is a concept that most scientists only worry about when they need some data, and mostly never after their project is complete. The exigencies of the vetting, review and publishing processes overtake the long-term view of making one's own data available to others with the same ease and openness that was desired when seeking data from others. This presentation describes our experience with acquiring data for our carbon modeling efforts, dealing with federal, state and local agencies, variety of data formats, some published, some not so easy to find, and documentation that ranges from excellent to non-existent. A set of indicators are proposed to place and determine the accessibility of scientific data -- those we are seeking and those we are producing -- in order to bring some transparency and clarity that can make data acquisition and sharing easier. The paper concludes with a proposal to utilize a free, open and well-recognized data marks such as CC0 (CC-Zero), Public Domain Dedication License, and CC-BY created by Creative Commons that would advertize the

  15. Possible Role of Green Chemistry in Addressing Environmenal Plastic Debris: Scientific, Economic and Policy Issues

    Science.gov (United States)

    Bayha, K. M.

    2016-02-01

    Plastics have revolutionized modern life, replacing other raw materials in a vast array of products, due to their ease in molding and shaping, as well as superior recalcitrance to wearing and aging. However, this functional benefit makes plastic one of the most problematic pollutants, since they accumulate as environmental debris for decades and possibly for centuries. Rightfully so, programs addressing plastic debris typically involve efforts to reduce consumption, reuse plastic products and recycle them when usefulness is complete. However, some of these options can be problematic for certain applications, as well as in countries that lack efficient municipal solid waste or recycling facilities. The principles of Green Chemistry were developed to help scientists design chemical products that reduce or eliminate the use or generation of hazardous substances. These principles have also been applied to developing sustainable or greener polymers for use in consumer plastics. For instance, the EPA's Green Chemistry Program awards the Presidential Green Chemistry Challenge Awards each year, with a large percentage of awards having gone to developments in greener polymers. Many of these advancements involve the development of sustainable bio-based, more degradable or more recyclable polymers that deliver significant environmental benefits. This presentation is meant to address what role the development of truly greener polymers might have in addressing environmental plastic debris in parallel with efforts to reduce, reuse and recycle. The intention is to evaluate the issues posed by traditional polymer types, address the ultimate goals of alternative polymer development and evaluate research on current alternative polymer technologies, in order to objectively assess their usefulness in addressing environmental plastic debris accumulation. In addition, the scientific, policy and market issues that may be impeding accurate development, evaluation and implementation of

  16. The Magnus-Rademaker Scientific Film Collection: Ethical Issues on Animal Experimentation (1908-1940).

    Science.gov (United States)

    Koehler, Peter J; Lameris, Bregt

    2016-01-01

    The Magnus-Rademaker scientific film collection (1908-1940) deals with the physiology of body posture by the equilibrium of reflex musculature contractions for which experimental studies were carried out with animals (e.g., labyrinthectomies, cerebellectomies, and brain stem sections) as well as observations done on patients. The films were made for demonstrations at congresses as well as educational objectives and film stills were published in their books. The purpose of the present study is to position these films and their makers within the contemporary discourse on ethical issues and animal rights in the Netherlands and the earlier international debates. Following an introduction on animal rights and antivivisection movements, we describe what Magnus and Rademaker thought about these issues. Their publications did not provide much information in this respect, probably reflecting their adherence to implicit ethical codes that did not need explicit mentioning in publications. Newspaper articles, however, revealed interesting information. Unnecessary suffering of an animal never found mercy in Magnus' opinion. The use of cinematography was expanded to the reduction of animal experimentation in student education, at least in the case of Rademaker, who in the 1930s was involved in a governmental committee for the regulation of vivisection and cooperated with the antivivisection movement. This resulted not only in a propaganda film for the movement but also in films that demonstrate physiological experiments for students with the purpose to avert repetition and to improve the teaching of experiments. We were able to identify the pertinent films in the Magnus-Rademaker film collection. The production of vivisection films with this purpose appears to have been common, as is shown in news messages in European medical journals of the period.

  17. Hanford Site organic waste tanks: History, waste properties, and scientific issues

    Energy Technology Data Exchange (ETDEWEB)

    Strachan, D.M.; Schulz, W.W.; Reynolds, D.A.

    1993-01-01

    Eight Hanford single-shell waste tanks are included on a safety watch list because they are thought to contain significant concentrations of various organic chemical. Potential dangers associated with the waste in these tanks include exothermic reaction, combustion, and release of hazardous vapors. In all eight tanks the measured waste temperatures are in the range 16 to 46[degree]C, far below the 250 to 380[degree]C temperatures necessary for onset of rapid exothermic reactions and initiation of deflagration. Investigation of the possibility of vapor release from Tank C-103 has been elevated to a top safety priority. There is a need to obtain an adequate number of truly representative vapor samples and for highly sensitive and capable methods and instruments to analyze these samples. Remaining scientific issues include: an understanding of the behavior and reaction of organic compounds in existing underground tank environments knowledge of the types and amounts of organic compounds in the tanks knowledge of selected physical and chemical properties of organic compounds source, composition, quality, and properties of the presently unidentified volatile organic compound(s) apparently evolving from Tank C-103.

  18. Hanford Site organic waste tanks: History, waste properties, and scientific issues. Hanford Tank Safety Project

    Energy Technology Data Exchange (ETDEWEB)

    Strachan, D.M.; Schulz, W.W.; Reynolds, D.A.

    1993-01-01

    Eight Hanford single-shell waste tanks are included on a safety watch list because they are thought to contain significant concentrations of various organic chemical. Potential dangers associated with the waste in these tanks include exothermic reaction, combustion, and release of hazardous vapors. In all eight tanks the measured waste temperatures are in the range 16 to 46{degree}C, far below the 250 to 380{degree}C temperatures necessary for onset of rapid exothermic reactions and initiation of deflagration. Investigation of the possibility of vapor release from Tank C-103 has been elevated to a top safety priority. There is a need to obtain an adequate number of truly representative vapor samples and for highly sensitive and capable methods and instruments to analyze these samples. Remaining scientific issues include: an understanding of the behavior and reaction of organic compounds in existing underground tank environments knowledge of the types and amounts of organic compounds in the tanks knowledge of selected physical and chemical properties of organic compounds source, composition, quality, and properties of the presently unidentified volatile organic compound(s) apparently evolving from Tank C-103.

  19. Scientific Literacy, Environmental Issues, and PISA 2006: The 2008 Paul F-Brandwein Lecture

    Science.gov (United States)

    Bybee, Rodger W.

    2008-01-01

    In today's world, scientific literacy has become essential to full participation of citizens. Certainly, important components of scientific literacy include resource use and environmental quality. The 2006 Program for International Student Assessment (PISA) centered on scientific literacy and included resources and environments as two contexts for…

  20. Scientific Literacy, Environmental Issues, and PISA 2006: The 2008 Paul F-Brandwein Lecture

    Science.gov (United States)

    Bybee, Rodger W.

    2008-01-01

    In today's world, scientific literacy has become essential to full participation of citizens. Certainly, important components of scientific literacy include resource use and environmental quality. The 2006 Program for International Student Assessment (PISA) centered on scientific literacy and included resources and environments as two contexts for…

  1. Using Next Generation Science Standards (NGSS) Practices to Address Scientific Misunderstandings Around Complex Environmental Issues

    Science.gov (United States)

    Turrin, M.; Kenna, T. C.

    2014-12-01

    The new NGSS provide an important opportunity for scientists to develop curriculum that links the practice of science to research-based data in order to improve understanding in areas of science that are both complex and confusing. Our curriculum focuses in particular on the fate and transport of anthropogenic radionuclides. Radioactivity, both naturally occurring and anthropogenic, is highly debated and largely misunderstood, and for large sections of the population is a source of scientific misunderstanding. Developed as part of the international GEOTRACES project which focuses on identifying ocean processes and quantifying fluxes that control the distributions of selected trace elements and isotopes in the ocean, and on establishing the sensitivity of these distributions to changing environmental conditions, the curriculum topic fits nicely into the applied focus of NGSS with both environmental and topical relevance. Our curriculum design focuses on small group discussion driven by questions, yet unlike more traditional curriculum pieces these are not questions posed to the students, rather they are questions posed by the students to facilitate their deeper understanding. Our curriculum design challenges the traditional question/answer memorization approach to instruction as we strive to develop an educational approach that supports the practice of science as well as the NGSS Cross Cutting Concepts and the Science & Engineering Practices. Our goal is for students to develop a methodology they can employ when faced with a complex scientific issue. Through background readings and team discussions they identify what type of information is important for them to know and where to find a reliable source for that information. Framing their discovery around key questions such as "What type of radioactive decay are we dealing with?", "What is the potential half-life of the isotope?", and "What are the pathways of transport of radioactivity?" allows students to evaluate a

  2. Using Social Media to Promote Pre-Service Science Teachers' Practices of Socio-Scientific Issue (SSI) - Based Teaching

    Science.gov (United States)

    Pitiporntapin, Sasithep; Lankford, Deanna Marie

    2015-01-01

    This paper addresses using social media to promote pre-service science teachers' practices of Socio-Scientific Issue (SSI) based teaching in a science classroom setting. We designed our research in two phases. The first phase examined pre-service science teachers' perceptions about using social media to promote their SSI-based teaching. The…

  3. Training in Decision-Making Strategies: An Approach to Enhance Students' Competence to Deal with Socio-Scientific Issues

    Science.gov (United States)

    Gresch, Helge; Hasselhorn, Marcus; Bögeholz, Susanne

    2013-01-01

    Dealing with socio-scientific issues in science classes enables students to participate productively in controversial discussions concerning ethical topics, such as sustainable development. In this respect, well-structured decision-making processes are essential for elaborate reasoning. To foster decision-making competence, a computer-based…

  4. Using Social Media to Promote Pre-Service Science Teachers' Practices of Socio-Scientific Issue (SSI) - Based Teaching

    Science.gov (United States)

    Pitiporntapin, Sasithep; Lankford, Deanna Marie

    2015-01-01

    This paper addresses using social media to promote pre-service science teachers' practices of Socio-Scientific Issue (SSI) based teaching in a science classroom setting. We designed our research in two phases. The first phase examined pre-service science teachers' perceptions about using social media to promote their SSI-based teaching. The…

  5. A Comparison Study of Augmented Reality versus Interactive Simulation Technology to Support Student Learning of a Socio-Scientific Issue

    Science.gov (United States)

    Chang, Hsin-Yi; Hsu, Ying-Shao; Wu, Hsin-Kai

    2016-01-01

    We investigated the impact of an augmented reality (AR) versus interactive simulation (IS) activity incorporated in a computer learning environment to facilitate students' learning of a socio-scientific issue (SSI) on nuclear power plants and radiation pollution. We employed a quasi-experimental research design. Two classes (a total of 45…

  6. Research and Teaching: Undergraduate Students' Scientifically Informed Decision Making about Socio-Hydrological Issues

    Science.gov (United States)

    Sabel, Jaime L.; Vo, Tina; Alred, Ashley; Dauer, Jenny M.; Forbes, Cory T.

    2017-01-01

    Although knowledge of disciplinary concepts and epistemic understanding of science are foundations of scientific literacy, students must learn to apply their knowledge to real-world situations. To engage effectively with contemporary water-related challenges with scientific and social dimensions, students need to understand the properties of water…

  7. [Psychocognitive and psychiatric disorders associated with developmental dyslexia: A clinical and scientific issue].

    Science.gov (United States)

    Huc-Chabrolle, M; Barthez, M-A; Tripi, G; Barthélémy, C; Bonnet-Brilhault, F

    2010-04-01

    issues. ADHD is the most frequent psychiatric disorder associated with dyslexia. Underpinnings of this link between the two disorders seem to rely on common cognitive and genetic factors. Some authors have proposed a candidate gene ADRA2A to determine the condition including ADHD and dyslexia. In addition, dyslexics are exposed to a higher risk of anxiodepressive and behavioural disorders. Dyslexic children experience three times more behavioural disorders and one third of children with behavioural problems turn out to be affected by dyslexia. The literature study reveals inconsistent findings about depressed mood among dyslexics, but evidence of a persistent increase in the rate of anxiety disorders. The authors put forward the impact of environmental factors to explain these psychiatric comorbidities. This review emphasizes dyslexia's comorbidities because they represent an important issue, both from a scientific and clinical point of view. Indeed, for clinicians, children showing multiple learning disabilities have specific reeducation and educational needs and dyslexics have a higher risk of emotional and behavioural disorders. On the other hand, dyslexia's comorbidity study provides a powerful method for researchers to investigate the still unknown physiopathology of dyslexia. 2009 L'Encéphale, Paris. Published by Elsevier Masson SAS. All rights reserved.

  8. Organizational Patterns of Scientific and Technical Libraries: An Examination of Three Issues

    Science.gov (United States)

    Waldhart, Thomas J.; Zweifel, Leroy G.

    1973-01-01

    Three aspects of the problem of library reorganization are considered with specific reference to scientific and technological libraries: the politics of centralization; the concept of accessibility; and the interaction of science and technology. (28 references) (Author)

  9. To What Extent do Biology Textbooks Contribute to Scientific Literacy? Criteria for Analysing Science-Technology-Society-Environment Issues

    Directory of Open Access Journals (Sweden)

    Florbela M. Calado

    2015-10-01

    Full Text Available Our article proposes a set of six criteria for analysing science-technology-society-environment (STSE issues in regular textbooks as to how they are expected to contribute to students’ scientific literacy. We chose genetics and gene technology as fields prolific in STSE issues. We derived our criteria (including 26 sub-criteria from a literature review of the debate in science education on how to increase scientific literacy. We inspected the textbooks regarding the relationships between science, technology, society, and environment, and considered the presence of the decontextualized and socially neutral view of science as distorted view. We, qualitatively and quantitatively, applied our set of criteria to two German Biology textbooks and identified, in total, 718 STSE statements. Based on the frequencies of different criteria and sub-criteria in the textbooks, we drew conclusions concerning STSE issues and the underlying conceptions of science and technology, which might hinder the furtherance of scientific literacy. The applicability of our approach in other science education contexts is discussed.

  10. Adults' Decision-Making about the Electronic Waste Issue: The Role of the Nature of Science Conceptualizations and Moral Concerns in Socio-Scientific Decision-Making

    Science.gov (United States)

    Yu, Yuqing

    2010-01-01

    Socio-scientific issues have become increasingly important in Science-Technology-Society (STS) education as a means to make science learning more relevant to students' lives. This study used the e-waste issue as a context to investigate two aspects of socio-scientific decision-making: (1) the relationship between the nature of science (NOS)…

  11. A Study in Physical and Mechanical Properties of Hemp Fibres

    Directory of Open Access Journals (Sweden)

    Asim Shahzad

    2013-01-01

    Full Text Available This paper presents the results of the experiments undertaken to evaluate various physical and mechanical properties of hemp fibres. The study of these properties is vital for comparison with similar properties of synthetic fibres and for assessing hemp fibres’ suitability for use as reinforcement in composite materials. The properties of hemp fibres were found to be good enough to be used as reinforcement in composite materials. However, the issues of relatively high moisture content of fibres, variability in fibre properties, and relatively poor fibre/matrix interfacial strength were identified as factors that can reduce the efficiency with which these fibres can be utilised.

  12. EDITORIAL: The 20th International Conference on Optical Fibre Sensors, OFS-20 The 20th International Conference on Optical Fibre Sensors, OFS-20

    Science.gov (United States)

    Culshaw, Brian; Ecke, Wolfgang; Jones, Julian; Tatam, Ralph; Willsch, Reinhardt

    2010-09-01

    communications, material science and data management along the way. This is, of course, the year commemorating half a century of the laser. Arguably, laser technology, most notably semiconductor lasers, has made the major contribution to fibre optic sensors, and precision-controlled laser sources are now effectively taken for granted within the fibre sensor community. We have also drawn on innovation in fibre communications: the fibre itself, the Bragg grating and the fibre amplifier—and more recently on material systems like photonic crystal fibres, biophotonics and nanostructures. In this issue you will find some examples of the intriguing research that exemplifies the best of current fibre sensor technology. The issue gives some impression of the many facets—scientific, technological and applications—that fibre sensors have on offer. It also exemplifies a truly international community which is brought together through the conference series. The next OFS meeting takes place in Ottawa, Canada on 15-19 May 2011 (see www.ofs21.org/), followed in the autumn of 2012 by an event in Beijing. We look forward to seeing you there.

  13. Interpretation of Scientific or Mathematical Concepts: Cognitive Issues and Instructional Implications.

    Science.gov (United States)

    1986-02-01

    conceptions aquired in priorschooling. Formal specifications of scientific concepts are rarely used and, even if they can be stated, they can often not be...and coherently throughout very broad domains. Furthermore, a very careful use of language and of other symbolic representations is needed to ensure

  14. Presenting Global Warming and Evolution as Public Health Issues to Encourage Acceptance of Scientific Evidence

    Science.gov (United States)

    Stover, Shawn K.; McArthur, Laurence B.; Mabry, Michelle L.

    2013-01-01

    Although evidence supporting anthropogenic global warming and evolution by natural selection is considerable, the public does not embrace these concepts. The current study explores the hypothesis that individuals will become more receptive to scientific viewpoints if evidence for evolution and implications of global warming are presented as issues…

  15. Arguing from Nature: The Role of "Nature" in Students' Argumentations on a Socio-Scientific Issue

    Science.gov (United States)

    Nielsen, Jan Alexis

    2012-01-01

    This paper explores how students invoked different conceptions of "nature" in eight socio-scientific group discussions about human gene therapy. The paper illustrates and discusses how the students articulated nature and to what extent they elicited science factual content in the process. While the students in this study invoked nature at key…

  16. Arguing from Nature: The Role of "Nature" in Students' Argumentations on a Socio-Scientific Issue

    Science.gov (United States)

    Nielsen, Jan Alexis

    2012-01-01

    This paper explores how students invoked different conceptions of "nature" in eight socio-scientific group discussions about human gene therapy. The paper illustrates and discusses how the students articulated nature and to what extent they elicited science factual content in the process. While the students in this study invoked nature at key…

  17. The implementation of integrated science teaching materials based socio-scientific issues to improve students scientific literacy for environmental pollution theme

    Science.gov (United States)

    Yenni, Rita; Hernani, Widodo, Ari

    2017-05-01

    The study aims to determine the increasing of students' science literacy skills on content aspects and competency of science by using Integrated Science teaching materials based Socio-scientific Issues (SSI) for environmental pollution theme. The method used in the study is quasi-experiment with nonequivalent pretest and posttest control group design. The students of experimental class used teaching materials based SSI, whereas the students of control class were still using the usual textbooks. The result of this study showed a significant difference between the value of N-gain of experimental class and control class, whichalso occurred in every indicator of content aspects and competency of science. This result indicates that using of Integrated Science teaching materials based SSI can improve content aspect and competency of science and can be used as teaching materials alternative in teaching of Integrated Science.

  18. Systems Engineering and Safety Issues in Scientific Facilities Subject to Ionizing Radiations

    Directory of Open Access Journals (Sweden)

    Pierre Bonnal

    2013-10-01

    Full Text Available The conception and development of large- scale scientific facilities emitting ionizing radiations rely more on project management practices in use in the process industry than on systems engineering practices. This paper aims to highlight possible reasons for this present situation and to propose some ways to enhance systems engineering so that the specific radiation safety requirements are considered and integrated in the approach. To do so, we have reviewed lessons learned from the management of large-scale scientific projects and more specifically that of the Large Hadron Collider project at CERN. It is shown that project management and systems engineering practices are complementary and can beneficially be assembled in an integrated and lean managerial framework that grants the appropriate amount of focus to safety and radiation safety aspects.

  19. Systems Engineering and Safety Issues in Scientific Facilities Subject to Ionizing Radiations

    Directory of Open Access Journals (Sweden)

    Pierre Bonnal

    2013-10-01

    Full Text Available The conception and development of large-scale scientific facilities emitting ionizing radiations rely more on project management practices in use in the process industry than on systems engineering practices. This paper aims to highlight possible reasons for this present situation and to propose some ways to enhance systems engineering so that the specific radiation safety requirements are considered and integrated in the approach. To do so, we have reviewed lessons learned from the management of large-scale scientific projects and more specifically that of the Large Hadron Collider project at CERN. It is shown that project management and systems engineering practices are complementary and can beneficially be assembled in an integrated and lean managerial framework that grants the appropriate amount of focus to safety and radiation safety aspects.

  20. For the Anniversary Edition of the Scientific Journal European Researcher. Series A – 110 issue

    Directory of Open Access Journals (Sweden)

    Goran Rajović

    2016-09-01

    Full Text Available This article is a review of the jubilee scientific journal "European Researcher. Series A ", marked at all in 2016 – the sixth anniversary, of regular and of continuous publication. In addition to the history of the newspaper are exposed to the development phase of its program concept. The journal is the period 2010 – 2016 year, profiled in an important factor of development and the formation of professional and scientific thought. Journal “European Research. Series A” is now open forum for publicizing and stimulating innovative thinking on all aspects of the social sciences, the entire international academic community. In all this we emphasize the infinite persistence, creative energy but also authoring and management merits chief editor and founder of the Journal, DrAleksandrCherkasov for survival and development for this great publishing project.

  1. "It's Still Science but Not Like Normal Science": Girls' Responses to the Teaching of Socio-Scientific Issues

    Science.gov (United States)

    Morris, Helen

    2014-01-01

    Socio-scientific issues, which are often controversial, involve the use of science and are of interest to society, raising ethical and moral dilemmas. Examples of these issues could include genetic technology or air pollution. Following a curriculum reform in England in 2006, socioscientific issues now have a heightened presence in the 14-16…

  2. Helically twisted photonic crystal fibres.

    Science.gov (United States)

    Russell, P St J; Beravat, R; Wong, G K L

    2017-02-28

    Recent theoretical and experimental work on helically twisted photonic crystal fibres (PCFs) is reviewed. Helical Bloch theory is introduced, including a new formalism based on the tight-binding approximation. It is used to explore and explain a variety of unusual effects that appear in a range of different twisted PCFs, including fibres with a single core and fibres with N cores arranged in a ring around the fibre axis. We discuss a new kind of birefringence that causes the propagation constants of left- and right-spinning optical vortices to be non-degenerate for the same order of orbital angular momentum (OAM). Topological effects, arising from the twisted periodic 'space', cause light to spiral around the fibre axis, with fascinating consequences, including the appearance of dips in the transmission spectrum and low loss guidance in coreless PCF. Discussing twisted fibres with a single off-axis core, we report that optical activity in a PCF is opposite in sign to that seen in a step-index fibre. Fabrication techniques are briefly described and emerging applications reviewed. The analytical results of helical Bloch theory are verified by an extensive series of 'numerical experiments' based on finite-element solutions of Maxwell's equations in a helicoidal frame.This article is part of the themed issue 'Optical orbital angular momentum'. © 2017 The Authors.

  3. Helically twisted photonic crystal fibres

    Science.gov (United States)

    Russell, P. St. J.; Beravat, R.; Wong, G. K. L.

    2017-02-01

    Recent theoretical and experimental work on helically twisted photonic crystal fibres (PCFs) is reviewed. Helical Bloch theory is introduced, including a new formalism based on the tight-binding approximation. It is used to explore and explain a variety of unusual effects that appear in a range of different twisted PCFs, including fibres with a single core and fibres with N cores arranged in a ring around the fibre axis. We discuss a new kind of birefringence that causes the propagation constants of left- and right-spinning optical vortices to be non-degenerate for the same order of orbital angular momentum (OAM). Topological effects, arising from the twisted periodic `space', cause light to spiral around the fibre axis, with fascinating consequences, including the appearance of dips in the transmission spectrum and low loss guidance in coreless PCF. Discussing twisted fibres with a single off-axis core, we report that optical activity in a PCF is opposite in sign to that seen in a step-index fibre. Fabrication techniques are briefly described and emerging applications reviewed. The analytical results of helical Bloch theory are verified by an extensive series of `numerical experiments' based on finite-element solutions of Maxwell's equations in a helicoidal frame. This article is part of the themed issue 'Optical orbital angular momentum'.

  4. Helically twisted photonic crystal fibres

    Science.gov (United States)

    Beravat, R.; Wong, G. K. L.

    2017-01-01

    Recent theoretical and experimental work on helically twisted photonic crystal fibres (PCFs) is reviewed. Helical Bloch theory is introduced, including a new formalism based on the tight-binding approximation. It is used to explore and explain a variety of unusual effects that appear in a range of different twisted PCFs, including fibres with a single core and fibres with N cores arranged in a ring around the fibre axis. We discuss a new kind of birefringence that causes the propagation constants of left- and right-spinning optical vortices to be non-degenerate for the same order of orbital angular momentum (OAM). Topological effects, arising from the twisted periodic ‘space’, cause light to spiral around the fibre axis, with fascinating consequences, including the appearance of dips in the transmission spectrum and low loss guidance in coreless PCF. Discussing twisted fibres with a single off-axis core, we report that optical activity in a PCF is opposite in sign to that seen in a step-index fibre. Fabrication techniques are briefly described and emerging applications reviewed. The analytical results of helical Bloch theory are verified by an extensive series of ‘numerical experiments’ based on finite-element solutions of Maxwell's equations in a helicoidal frame. This article is part of the themed issue ‘Optical orbital angular momentum’. PMID:28069771

  5. Technical Scientific Attaches and domotics. A special issue; Technisch Wetenschappelijk Attaches en domotica. Special

    Energy Technology Data Exchange (ETDEWEB)

    Kleinenberg, R.A. [Ministerie van Economische Zaken, The Hague (Netherlands); Uythof, B.H. [Invenit, Domotica Platform Nederland, Amsterdam (Netherlands); Benedetti, D [Ufficio Tecnico-Scientifico, Ambasciata del Regno dei Paesi Bassi, Rome (Italy); Van Wijngaarden, W.L. [Buero fuer Wissenschaft und Technologie, Kgl. Niederlaendische Botschaft, Bonn (Germany); Leniger, H.D.F. [Bureau du Conseiller Scientifique et Technique, Ambassade des Pays-Bas, Paris (France); Kieboom, J.P. [Office for Science and Technology, Royal Netherlands Embassy, Singapore (Singapore); Van Kooij, E.H. [Netherlands Office for Science and Technology, Royal Netherlands Embassy, Tokyo (Japan); Schuurmans, H.J.A. [Netherlands Office for Science and Technology, San Mateo, CA (United States)

    2000-04-01

    In this Dutch magazine Dutch businesses and institutes are informed about technological developments in industrialized countries (USA, Canada, Japan, South Korea, Taiwan, Singapore, Germany, France and Italy). In this special issue attaches in the different countries present information on developments and trends with respect to domotics, building automation, home networks, etc.

  6. Scientific issues related to Codex Alimentarius goals: a review of principles, with examples.

    Science.gov (United States)

    Somogyi, Arpad; Hathcock, John; Biesalski, Hans Konrad; Blumberg, Jeffrey B; Antoine, Jean-Michel; Edwards, Gareth; Prock, Peter

    2011-06-01

    The Codex Alimentarius provides the food standards and guidelines recognized by the World Trade Organization as the primary authority for use in settlement of related trade disputes. Codex bases its decisions primarily on scientific principles and evidence, although other legitimate factors such as economic and societal values may be considered. Codex has two primary aims: to protect consumers' health and assure fair practices in food trade. Codex documents may provide templates for individual nations but are not binding for domestic policies. Despite many advances over the last couple of decades, misunderstandings and controversies have interfered with important aspects of progress which Codex needs to accomplish, especially in the areas of claims of benefits related to food or nutrient consumption and the establishment of the safety of these items. Claims for health benefits should be based on the totality of available scientific evidence, including observational data collected from large populations as well as the results from randomized clinical trials. Safety should be evaluated by risk assessment on high quality experimental data, with anecdotal information having a lesser role. Regulatory policy would be improved if "history of safe use" were to be better defined and described.

  7. Role of Water in Electron-Initiated Processes and Radical Chemistry: Issues and Scientific Advances

    Energy Technology Data Exchange (ETDEWEB)

    Garrett, Bruce C.; Dixon, David A.; Camaioni, Donald M.; Chipman, Daniel M.; Johnson, Mark A.; Jonah, Charles D.; Kimmel, Greg A.; Miller, John H.; Rescigno, Tom; Rossky, Peter J.; Xantheas, Sotiris S.; Colson, Steve D.; Laufer, Allan H.; Ray, Douglas; Barbara, Paul F.; Bartels, David M.; Bowen, Kit H.; Becker, Kurt H.; Bradforth, Stephen E.; Carmichael, Ian; Coe, James V.; Corrales, L. Rene; Cowin, James P.; Dupuis, Michel; Eisenthal, Kenneth B.; Franz, James A.; Gutowski, Maciej S.; Jordon, Kenneth D.; Kay, Bruce D.; La Verne, Jay A.; Lymar, Sergei V.; Madey, Theodore E.; Mccurdy, C. W.; Meisel, Dan; Mukamel, Shaul; Nilsson, Anders R.; Orlando, Thomas M.; Petrik, Nikolay G.; Pimblott, Simon M.; Rustad, James R.; Schenter, Gregory K.; Singer, Sherwin J.; Tokmakoff, Andrei; Wang, Lai-Sheng; Wittig, Curt; Zwier, Timothy S.

    2005-01-12

    An understanding of electron-initiated processes in aqueous systems and the subsequent radical chemistry these processes induce is significant in such diverse fields as waste remediation and environmental cleanup, radiation processing, nuclear reactors, and medical diagnosis and therapy. We review the state of the art in the physical chemistry and chemical physics of electron-initiated processes in aqueous systems and raise critical research issues and fundamental questions that remain unanswered.

  8. Methodological and Practical Issues of Scientific Research on the Retail Market

    Directory of Open Access Journals (Sweden)

    Balasescu, M.

    2014-06-01

    Full Text Available This paper highlights the role and importance of marketing research in a dynamic and complex sector such as retail. The paper approaches the theoretical issues related to the methods and instruments of marketing research appropriate for the retail market. The theory about qualitative and quantitative research methods is supported by relevant examples which lead to a better understanding of the marketing research process and of its effectiveness on retail activities.

  9. [Prof. Giuseppe Moscati (1880-1927). A special issue on his scientific production].

    Science.gov (United States)

    Cascella, Marco

    2016-08-01

    Professor Giuseppe Moscati (1880-1927) was canonized by the Catholic Church in 1987. This act recognized the extraordinary qualities of a doctor who, considering his work as a "sublime mission", dedicated his life to helping the sick. The fame of the "Holy doctor" or "doctor of the poor", as people called him, was soon widespread and, immediately after his death, made him the subject of several biographies. These treatises, mainly written by religious hagiographers, have little analyzed Moscati as a doctor and scientist, or, in rare cases, privileged the description of his medical career, touching only marginally salient aspects of his work as a scientist and researcher. The purpose of this paper is to provide an insight into the figure of Moscati as a scientist, contextualizing his research activities in the scientific fields of biochemistry and physiology, which were flourishing in the early twentieth century. By a more careful analysis, his scientific production appears original for the resource-poor context and the innovative research method. The Italian scientist, combining physiological chemistry and biochemistry at the clinic, anticipated the birth of modern branches as the "Laboratory Medicine" and the "Clinical Pathology". In particular, he carried out studies on diabetes, storage diseases, metabolism, toxicology, pathology, nephrology and occupational diseases. Moreover, he anticipated the concept of modern laboratory in the oncological field as means for the characterization of the "nature" of neoplasms and related therapeutic approaches. Therefore, even if Moscati was rarely mentioned by the sources of the history of medicine, it is safe to assume that the fame of the Saint has paradoxically eclipsed that of the scientist, preventing him from receiving the necessary reward.

  10. Ethics issues in scientific data and service provision: evidence and challenges for the European Plate Observing System (EPOS)

    Science.gov (United States)

    Cocco, Massimo; Freda, Carmela; Haslinger, Florian; Consortium, Epos

    2016-04-01

    Addressing Ethics issues is nowadays a relevant challenge for any initiative, program or project dealing with scientific data and products provision, access to services for scientific purposes and communication with different stakeholders, including society. This is corroborated by the evidence that Ethics has very high priority in EU funded research. Indeed, all the activities carried out under Horizon 2020 must comply with ethical principles and national, Union and international legislation. This implies that "For all activities funded by the European Union, Ethics is an integral part of research from beginning to end, and ethical compliance is seen as pivotal to achieve real research excellence." Here, we present the experience of EPOS, a public pan-European research infrastructure. EPOS aims at integrating data, data products, services and software (DDSS) for solid Earth science generated and provided by monitoring networks, observing systems and facilities belonging to European countries. EPOS fosters the integrated use of multidisciplinary solid Earth data to improve the understanding of physical and chemical processes controlling earthquakes, volcanic eruptions, tsunamis as well as those driving tectonics and surface dynamics. The EPOS integration plan will make significant contributions to understanding and mitigating geo-hazards, yielding data for hazard assessment, data products for engaging different stakeholders, and services for training, education and communication to society. Numerous national research infrastructures engaged in EPOS are deployed for the monitoring of areas prone to geo-hazards and for the surveillance of the national territory including areas used for exploiting geo-resources. The EPOS community is therefore already trained to provide services to public (civil defence agencies, local and national authorities) and private (petroleum industry, mining industry, geothermal companies, aviation security) stakeholders. Our ability to

  11. Assessing HIV risk among women who have sex with women: scientific and communication issues.

    Science.gov (United States)

    Kennedy, M B; Scarlett, M I; Duerr, A C; Chu, S Y

    1995-01-01

    Data on human immunodeficiency virus (HIV) risk faced by women who have sex with women (WSW) are scarce. The biologic risk of female-to-female transmission is not known. Several surveys have reported that certain groups of WSW engage in behaviors that put them at risk for HIV infection, such as unprotected sex with men, unprotected sex or sharing of sex toys with women, and injection drug use. WSW may also be at risk for HIV through use of unscreened semen from sources other than sperm banks. An evaluation of HIV risk behaviors among WSW has been hampered by methodological issues, such as lack of data about the extent of the population, the use of standard definitions in research, and the design of data collection instruments. HIV prevention efforts have been hampered by communication issues, such as what "safer sex" means to this population and difficulties in interactions with health care providers. Prevention interventions for this population must address behaviors that put WSW at risk for HIV infection, including injection drug use and unprotected penile sex. At the same time, the possibility of sexual transmission of HIV via female-to-female sex should not be discounted. Health providers should understand that sexual identity does not necessarily predict sexual behavior and should not make any assumptions regarding HIV risk based on self-reported or presumed sexual identity.

  12. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of health claims related to rye fibre and changes in bowel function (ID 825), reduction of post-prandial glycaemic responses (ID 826) and maintenance of normal blood LDL-cholesterol

    DEFF Research Database (Denmark)

    Tetens, Inge

    claims in relation to rye fibre and changes in bowel function, reduction of post-prandial glycaemic responses and maintenance of normal blood LDL-cholesterol concentrations. The scientific substantiation is based on the information provided by the Member States in the consolidated list of Article 13...

  13. Preservice special education teachers' understandings, enactments, views, and plans for scientific inquiry: Issues and hopes

    Science.gov (United States)

    Ghosh, Rajlakshmi

    This study examined the understandings, enactments, views, and plans for scientific inquiry held by preservice special education teachers enrolled in a K--8 general science methods course. Sixteen participants from four special education concentration areas---Mild to Moderate Educational Needs, Moderate to Intense Educational Needs, Mild to Moderate Educational Needs with Language Arts and Reading Emphasis, and Early Childhood Intervention---participated in this study. Qualitative data were collected from questionnaires, interviews, teaching videos, lesson plans, planning commentaries, and reflection papers. Data were analyzed using a grounded theory approach (Strauss & Corbin, 1990) and compared against the theoretical view of inquiry as conceptualized by the National Research Council (NRC, 2000). The participants held unique interpretations of inquiry that only partially matched with the theoretical insights provided by the NRC. The participants' previous science learning experiences and experiences in special education played an important role in shaping their conceptualizations of inquiry as learned in the science methods class. The impacts of such unique interpretations are discussed with reference to both science education and special education, and implications for teacher education are provided.

  14. The International Flow of Scientific and Technical Talent: Data, Policies and Issues. Proceedings of the 1985 Joint Meeting of the Scientific Manpower Commission and the Engineering Manpower Commission (Washington, D.C., May 7, 1985).

    Science.gov (United States)

    Barthel, Sue V., Ed.; Early, Julie A., Ed.

    Issues related to the international flow of scientific and technical talent are discussed in these proceedings. The symposium was organized into three panels covering the topics of data, policies, and issues as they relate to the utilization of foreign talent. The panel on data provided information on the number of foreign students in United…

  15. Scientific Issues Relevant to Setting Regulatory Criteria to Identify Endocrine-Disrupting Substances in the European Union

    Science.gov (United States)

    Slama, Rémy; Bourguignon, Jean-Pierre; Demeneix, Barbara; Ivell, Richard; Panzica, Giancarlo; Kortenkamp, Andreas; Zoeller, R. Thomas

    2016-01-01

    , Kortenkamp A, Zoeller RT. 2016. Scientific issues relevant to setting regulatory criteria to identify endocrine disrupting substances in the European Union. Environ Health Perspect 124:1497–1503; http://dx.doi.org/10.1289/EHP217 PMID:27108591

  16. Self-reported experiences of discrimination and health: scientific advances, ongoing controversies, and emerging issues.

    Science.gov (United States)

    Lewis, Tené T; Cogburn, Courtney D; Williams, David R

    2015-01-01

    Over the past two decades, research examining the impact of self-reported experiences of discrimination on mental and physical health has increased dramatically. Studies have found consistent associations between exposure to discrimination and a wide range of Diagnostic and Statistical Manual of Mental Disorders (DSM)-diagnosed mental disorders as well as objective physical health outcomes. Associations are seen in cross-sectional as well as longitudinal studies and persist even after adjustment for confounding variables, including personality characteristics and other threats to validity. However, controversies remain, particularly around the best approach to measuring experiences of discrimination, the significance of racial/ethnic discrimination versus overall mistreatment, the need to account for "intersectionalities," and the importance of comprehensive assessments. These issues are discussed in detail, along with emerging areas of emphasis including cyber discrimination, anticipatory stress or vigilance around discrimination, and interventions with potential to reduce the negative effects of discrimination on health. We also discuss priorities for future research and implications for interventions and policy.

  17. Positive visual phenomena in space: A scientific case and a safety issue in space travel.

    Science.gov (United States)

    Sannita, Walter G; Narici, Livio; Picozza, Piergiorgio

    2006-07-01

    Most astronauts on Apollo, Skylab, and MIR reported 'flashes of light' occurring in different shapes and apparently moving across the visual field, in the absence of auditory, somatosensory, or olfactory abnormal percepts. A temporal correlation with heavy nuclei or protons has been documented in space and comparable phosphenes were observed by volunteers whose eyes were exposed to accelerated heavy ions at intensities below the threshold for Cerenkov visible radiation. An interaction between heavy ions and the retina was suggested. However, the biophysics of heavy ions or protons action remains undefined, the effects on photoreceptors and neuroretina have not been differentiated, and some direct action on the visual cortex never ruled out. Phosphenes are common in migraine and are known to occur also in response to the electrical stimulation of ganglion cells (in retinas without photoreceptors), optic pathways or visual cortex, with mechanisms that bypass the chemically gated channels. Intrinsic photosensitive ganglion cells exist in the retina of teleost fish and mammals. In the hypothesis of a peculiar sensitivity to subatomic particles of the visual system, phosphenes due to the activation of processes by-passing the photoreceptors would raise questions about human safety in space. The issue is particularly relevant with experiments of increasing duration being now operative in the International Space Station (ISS) and with plans of space travel outside the geomagnetic shield. Research is in progress both in the ISS and on animal models, in the framework of the NASA/ESA actions to improve the astronauts' health in space.

  18. SELF-REPORTED EXPERIENCES OF DISCRIMINATION AND HEALTH: SCIENTIFIC ADVANCES, ONGOING CONTROVERSIES, AND EMERGING ISSUES

    Science.gov (United States)

    Lewis, Tené T.; Cogburn, Courtney D.; Williams, David R.

    2017-01-01

    Over the past two decades, research examining the impact of self-reported experiences of discrimination on mental and physical health has increased dramatically. Studies have found consistent associations between exposure to discrimination and a wide range of DSM-diagnosed mental disorders, as well as objective physical health outcomes. Associations are seen in cross-sectional as well as longitudinal studies and persist even after adjustment for controls, including personality characteristics and other threats to validity. However, controversies remain, particularly around the best approach to measuring experiences of discrimination; the significance of racial/ethnic discrimination versus overall mistreatment; the need to account for “intersectionalities”; and the importance of comprehensive assessments. These issues are discussed in detail, along with emerging areas of emphasis including: cyber-discrimination; anticipatory stress or vigilance around discrimination; and interventions with potential to reduce the negative effects of discrimination on health. We also discuss priorities for future research, and implications for interventions and policy. PMID:25581238

  19. Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC): An Introduction to the Scientific Issues

    Science.gov (United States)

    Bentzen, Søren M.; Constine, Louis S.; Deasy, Joseph O.; Eisbruch, Avi; Jackson, Andrew; Marks, Lawrence B.; Haken, Randall K. Ten; Yorke, Ellen D.

    2012-01-01

    Advances in dose/volume/outcome (or normal tissue complication probability, NTCP) modeling since the seminal Emami paper from 1991 are reviewed. There has been some progress with an increasing number of studies on large patient samples with three-dimensional dosimetry. Nevertheless, NTCP models are not ideal. Issues related to the grading of side effects, selection of appropriate statistical methods, testing of internal and external model validity, and quantification of predictive power and statistical uncertainty, all limit the usefulness of much of the published literature. Synthesis (meta-analysis) of data from multiple studies is often impossible due to sub-optimal primary analysis, insufficient reporting and variations in the models and predictors analyzed. Clinical limitations to the current knowledge-base includes the need for more data on the effect of patient-related co-factors, interactions between dose-distribution and cytotoxic or molecular targeted agents, and the effect of dose fractions and overall treatment time in relation to non-uniform dose distributions. Research priorities for the next 5 to 10 years are proposed. PMID:20171515

  20. Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC): an introduction to the scientific issues.

    Science.gov (United States)

    Bentzen, Søren M; Constine, Louis S; Deasy, Joseph O; Eisbruch, Avi; Jackson, Andrew; Marks, Lawrence B; Ten Haken, Randall K; Yorke, Ellen D

    2010-03-01

    Advances in dose-volume/outcome (or normal tissue complication probability, NTCP) modeling since the seminal Emami paper from 1991 are reviewed. There has been some progress with an increasing number of studies on large patient samples with three-dimensional dosimetry. Nevertheless, NTCP models are not ideal. Issues related to the grading of side effects, selection of appropriate statistical methods, testing of internal and external model validity, and quantification of predictive power and statistical uncertainty, all limit the usefulness of much of the published literature. Synthesis (meta-analysis) of data from multiple studies is often impossible because of suboptimal primary analysis, insufficient reporting and variations in the models and predictors analyzed. Clinical limitations to the current knowledge base include the need for more data on the effect of patient-related cofactors, interactions between dose distribution and cytotoxic or molecular targeted agents, and the effect of dose fractions and overall treatment time in relation to nonuniform dose distributions. Research priorities for the next 5-10 years are proposed.

  1. The Relationship of Science Knowledge, Attitude and Decision Making on Socio-Scientific Issues: The Case Study of Students' Debates on a Nuclear Power Plant in Korea

    Science.gov (United States)

    Jho, Hunkoog; Yoon, Hye-Gyoung; Kim, Mijung

    2014-01-01

    The purpose of this study was to investigate the relationship of students' understanding of science knowledge, attitude and decision making on socio-scientific issues (SSI), especially on the issues of nuclear energy in Korea. SSI-focused instructions were developed to encourage students to understand and reflect on knowledge, attitude and…

  2. Scientific Integrity and Professional Ethics at AGU - Strategies and Actions to Impact Sexual Harassment in Science and other Work Climate Issues

    Science.gov (United States)

    McPhaden, Michael; Davidson, Eric; McEntee, Christine; Williams, Billy

    2017-04-01

    The American Geophysical Union (AGU), a scientific society of 62,000 members worldwide, has established a set of scientific integrity and professional ethics guidelines for the actions of its members, for the governance of the union in its internal activities, and for the operations and participation in its publications and scientific meetings. More recently AGU has undertaken strategies and actions to help address the issue of harassment in the sciences and other work climate issues. This presentation will provide an overview of the role of scientific societies in helping to address these important issues, as well as specific strategies and actions underway at AGU and other societies. Progress to date and remaining challenges of this effort will be discussed, including AGU's work to provide additional program strength in this area.

  3. Training in Decision-making Strategies: An approach to enhance students' competence to deal with socio-scientific issues

    Science.gov (United States)

    Gresch, Helge; Hasselhorn, Marcus; Bögeholz, Susanne

    2013-10-01

    Dealing with socio-scientific issues in science classes enables students to participate productively in controversial discussions concerning ethical topics, such as sustainable development. In this respect, well-structured decision-making processes are essential for elaborate reasoning. To foster decision-making competence, a computer-based programme was developed that trains secondary school students (grades 11-13) in decision-making strategies. The main research question is: does training students to use these strategies foster decision-making competence? In addition, the influence of meta-decision aids was examined. Students conducted a task analysis to select an appropriate strategy prior to the decision-making process. Hence, the second research question is: does combining decision-making training with a task analysis enhance decision-making competence at a higher rate? To answer these questions, 386 students were tested in a pre-post-follow-up control-group design that included two training groups (decision-making strategies/decision-making strategies combined with a task analysis) and a control group (decision-making with additional ecological information instead of strategic training). An open-ended questionnaire was used to assess decision-making competence in situations related to sustainable development. The decision-making training led to a significant improvement in the post-test and the follow-up, which was administered three months after the training. Long-term effects on the quality of the students' decisions were evident for both training groups. Gains in competence when reflecting upon the decision-making processes of others were found, to a lesser extent, in the training group that received the additional meta-decision training. In conclusion, training in decision-making strategies is a promising approach to deal with socio-scientific issues related to sustainable development.

  4. Adults' decision-making about the electronic waste issue: The role of the nature of science conceptualizations and moral concerns in socio-scientific decision-making

    Science.gov (United States)

    Yu, Yuqing

    Socio-scientific issues have become increasingly important in Science-Technology-Society (STS) education as a means to make science learning more relevant to students' lives. This study used the e-waste issue as a context to investigate two aspects of socio-scientific decision-making: (1) the relationship between the nature of science (NOS) conceptualizations and decision-making; and (2) moral concerns involved in the process of decision-making. This study contributes to the field of socio-scientific issue research and STS education in the following ways. First, it is the first study that performed meta-analysis to seek the relationship between the NOS understanding and decision-making. This study concludes that valuable NOS conceptualizations that are highly related to the socio-scientific issue under investigation, rather than general NOS understanding, exert statistically significant influences on decision-making. Second, this study empirically examined the Multiple Responses Model (MRM), which enables the transfer of qualitative NOS responses into quantitative data, and hence, inferential statistics. The current study justifies the significance of unidimensionality to the application of the MRM. It addresses the limitations associated with the MRM and provides implications for future use of the MRM in other contexts. Finally, the study explores the role of moral concerns in socio-scientific decision-making. Eight participants engaged in interviews that were designed to elicit their reactions and feelings regarding the issue of exporting e-waste to poor countries. Qualitative analyses demonstrated that moral considerations were significant influences on decision-making. In addition, participants' action responses revealed that they were motivated to take action to help the environment. The study has implications for socio-scientific issue studies in other contexts and for teacher education programs that use socio-scientific issues to advance teachers' reasoning

  5. Revisiting the Environmental and Socioeconomic Effects of Population Growth: a Fundamental but Fading Issue in Modern Scientific, Public, and Political Circles

    Directory of Open Access Journals (Sweden)

    Camilo Mora

    2014-03-01

    Full Text Available Reversing ongoing declines in human welfare and biodiversity is at the core of human development. Although numerous institutions and avenues are in place to reverse such trends, there seems to be limited consideration of population growth as an ultimate driver. I review recent studies showing how the issue of population growth has been downplayed and trivialized among scientific fields, which may in part account for the reduced public interest in the issue and in turn the limited will for policy action. Different sources of evidence suggest that population growth could fundamentally affect society, nature, and the climate. Although tackling the issue of overpopulation will suffer from major impediments including scientific motivation, public scientific illiteracy, religion, and media attention, ongoing neglect of this issue will increase not only the extent of anthropogenic stressors but also the struggle associated with strategies to reverse biodiversity loss and improve human welfare.

  6. Culturally Equipped for Socio-Scientific Issues? A comparative study on how teachers and students in mono- and multiethnic schools handle work with complex issues

    Science.gov (United States)

    Ideland, Malin; Malmberg, Claes; Winberg, Mikael

    2011-09-01

    Socio-scientific issues (SSI) are not only said to increase students' interest in science, but they also strengthen the generic skills of teamwork, problem-solving, and media literacy. At the same time, these skills are prerequisites for successful work with SSI. The aim of the study is to analyze what happens when SSI are implemented in science classrooms with various degrees of ethnic diversity and socio-cultural status. We are also interested in knowing how teachers structure the SSI work from discourses on what suits different students. Quantitative and qualitative methods are combined, for example, questionnaires and ethnographic fieldwork, presented through partial least squares analysis and thick descriptions. We can notice discursive differences between 'Us' and 'The Other' and between mono- and multiethnic schools. In an earlier research, images of differences between the different student groups emerged, and we can find these in the results from the questionnaires. In an observation study, another pattern appeared that indicated similarities rather than differences between mono- and multiethnic classrooms. The students are first of all inside the discourse of 'the successful student.' Noteworthy is that the teachers' roles correspond better with the discourse than with how students actually act. The study also shows that SSI articulate a collision between different discourses on education: a discourse on differences between students in multi- and monoethnic classrooms; a discourse on how to become a successful student; and a discourse on the school's mission to educate participating citizens. It is suggested that schools should relate to, expose, and articulate discursive clashes that emerge when introducing new work forms.

  7. Simulation of complex phenomena in optical fibres

    CERN Document Server

    Allington-Smith, Jeremy; Lemke, Ulrike

    2012-01-01

    Optical fibres are essential for many types of highly-multiplexed and precision spectroscopy. The success of the new generation of multifibre instruments under construction to investigate fundamental problems in cosmology, such as the nature of dark energy, requires accurate modellisation of the fibre system to achieve their signal-to-noise goals. Despite their simple construction, fibres exhibit unexpected behaviour including non-conservation of Etendue (Focal Ratio Degradation; FRD) and modal noise. Furthermore, new fibre geometries (non-circular or tapered) have become available to improve the scrambling properties that, together with modal noise, limit the achievable SNR in precision spectroscopy. These issues have often been addressed by extensive tests on candidate fibres and their terminations but these are difficult and time-consuming. Modelling by ray-tracing and wave analysis is possible with commercial software packages but these do not address the more complex features, in particular FRD. We use a...

  8. Learning science content through socio-scientific issues-based instruction: a multi-level assessment study

    Science.gov (United States)

    Sadler, Troy D.; Romine, William L.; Sami Topçu, Mustafa

    2016-07-01

    Science educators have presented numerous conceptual and theoretical arguments in favor of teaching science through the exploration of socio-scientific issues (SSI). However, the empirical knowledge base regarding the extent to which SSI-based instruction supports student learning of science content is limited both in terms of the number of studies that have been conducted in this area and the quality of research. This research sought to answer two questions: (1) To what extent does SSI-based instruction support student learning of science content? and (2) How do assessments at variable distances from the curriculum reveal patterns of learning associated with SSI-based instruction? Sixty-nine secondary students taught by three teachers participated in the study. Three teachers implemented an SSI intervention focused on the use of biotechnology for identifying and treating sexually transmitted diseases. We found that students demonstrated statistically and practically significant gains in content knowledge as measured by both proximal and distal assessments. These findings support the claim that SSI-based teaching can foster content learning and improved performance on high-stakes tests.

  9. A teaching-learning sequence on a socio-scientific issue: analysis and evaluation of its implementation in the classroom*

    Science.gov (United States)

    Vázquez-Alonso, Ángel; Aponte, Abdiel; Manassero-Mas, María-Antonia; Montesano, Marisa

    2016-07-01

    This study examines the effectiveness of a teaching-learning sequence (TLS) to improve the understanding of the influences and interactions between a technology (mining) and society. The aim of the study is also to show the possibility of both teaching and assessing the most innovative issues and aspects of scientific competence and their impact on the understanding of the nature of science. The methodology used a quasi-experimental, pre-post-test design with a control group, with pre-post-test differences as the empirical indicators of improved understanding. Improvements were modest, as the empirical differences (pre-post and experimental-control group) were not large, but the experimental group scored more highly than the control group. The areas that showed improvement were identified. The paper includes the TLS itself and the standardized assessment tools that are functional and transferable to other researchers and teachers. This paper first appeared in Educ. Quim (2014), 25(1), 190-202, a journal in Spanish. It appears by kind permission of the Editor, Professor Jose Chamizo. It was chosen because it illustrates the value of studies that use a standard procedure to address learning in a novel context.

  10. 火星探测的主要科学问题%Major scientific issues involved in Mars exploration

    Institute of Scientific and Technical Information of China (English)

    欧阳自远; 肖福根

    2011-01-01

    Among the planets of the solar system discovered so far, the similar features between the Mars and the Earth is the most prominent. Therefore, the Mars takes an important place in human's dreams. The issue about Mars water and life inspires the curiosity of exploring the Mars, and becomes a drive of successive Mars explorations. How did the Mars evolve and what is behind this evolution? What is the relationship between the evolutions of the Mars and the solar system? Can we make the Mars a green planet fit for sustainable human habitation and development? One must unveil these major scientific issues in the course of their Mars explorations. Only after these issues are solved one by one can we go on to think about the future of the Earth and mankind as related with the Mars.%在太阳系的行星中,火星与地球之间存在最多的相似之处,因此,火星是一颗承载人类最多梦想的星球.火星有水和生命存在的问题,激发了人类火星探索的好奇心,成为人类持续探测火星的推动力.火星的起源和演化与太阳系形成过程的关系,火星与类地行星的共性和特性,是当代行星科学研究的重要内容.为了人类社会的可持续发展,火星可否改造成为适宜人类居住的绿色星球--这些是人类在火星探测中必须面对的重大科学问题.只有这些重大科学问题被一一解答,我们才能清晰地去思考地球和人类自身的未来!

  11. Simulation of complex phenomena in optical fibres

    Science.gov (United States)

    Allington-Smith, Jeremy; Murray, Graham; Lemke, Ulrike

    2012-12-01

    Optical fibres are essential for many types of highly multiplexed and precision spectroscopy. The success of the new generation of multifibre instruments under construction to investigate fundamental problems in cosmology, such as the nature of dark energy, requires accurate modellization of the fibre system to achieve their signal-to-noise ratio (SNR) goals. Despite their simple construction, fibres exhibit unexpected behaviour including non-conservation of etendue (focal ratio degradation, FRD) and modal noise. Furthermore, new fibre geometries (non-circular or tapered) have become available to improve the scrambling properties that, together with modal noise, limit the achievable SNR in precision spectroscopy. These issues have often been addressed by extensive tests on candidate fibres and their terminations, but these are difficult and time-consuming. Modelling by ray tracing and wave analysis is possible with commercial software packages, but these do not address the more complex features, in particular FRD. We use a phase-tracking ray-tracing method to provide a practical description of FRD derived from our previous experimental work on circular fibres and apply it to non-standard fibres. This allows the relationship between scrambling and FRD to be quantified for the first time. We find that scrambling primarily affects the shape of the near-field pattern but has negligible effect on the barycentre. FRD helps to homogenize the near-field pattern but does not make it completely uniform. Fibres with polygonal cross-section improve scrambling without amplifying the FRD. Elliptical fibres, in conjunction with tapering, may offer an efficient means of image slicing to improve the product of resolving power and throughput, but the result is sensitive to the details of illumination. We also investigated the performance of fibres close to the limiting numerical aperture since this may affect the uniformity of the SNR for some prime focus fibre instrumentation.

  12. The establishment of a socio-scientific issue in a group of teachers: a polyphonic process of unveiling the concrete reality

    Directory of Open Access Journals (Sweden)

    Paulo Gabriel Franco dos Santos

    2012-12-01

    Full Text Available This article presents part of a broader research an d seeks to elucidate the process of setting up a Socio-scientific Issue in a group of teachers at a public school. Assuming that a Socio-scientific Issue must aggregate those involved in the educational process in situations of dialogue, argumentation and construction of a positioning, we understand that the recognition of the controversy or of the legitimacy of the theme in the context at stake is crucial to achieving the desired goals. Thus, starting from subsidies from the Critical Theory of Society, we characterize the process of setting up a Socio-scientific Issue among teachers as an exercise of unveiling the concrete reality, listing problematic, controversial and open to criticism aspects of Science and Technology. Thus, the Socio-scientific Issue is listed out in the group as soon as it is established a polyphonic dialogue where all participants stand, recognize the fertility of the theme for the intended educational context and can speak of it with propriety

  13. Case Studies of the Development of Science Teachers' Practices of Socio-Scientific Issue (SSI)-Based Teaching through a Professional Development Program

    Science.gov (United States)

    Pitiporntapin, Sasithep; Srisakuna, Suchada

    2017-01-01

    This research aimed to assess three case studies of in-service science teachers regarding their practices of socio-scientific issue (SSI)-based teaching as they participated in a specially developed professional development (PD) program. Data were collected throughout the PD program from group discussions, observations, interviews, and the review…

  14. Mainstream Issues of Education and Public Awareness of Space Activities and Sciences among universities and Scientific Institutes.

    Science.gov (United States)

    Singh, Balbir

    This paper is an effort to study and analyze several constraints and issues of space technology and education that organizations other than governmental organizations face in awareness program. In recent years, advancements in technologies have made it possible for Volunteer and Technical Communities, non-government organizations, private agencies and academic research institutions to provide increasing support to space education management and emphasis on response efforts. Important cornerstones of this effort and support are the possibility to access and take advantage of satellite imagery as well as the use of other space-based technologies such as telecommunications satellites and global navigation satellite systems included in main curriculum plus the implementation of programs for use of high class sophisticated technologies used by industries to the students and researchers of non-space faring nations. The authors recognize the importance of such new methodologies for education and public Awareness. This paper demonstrates many hurdles universities and scientific institutions face including lack of access in terms of financial and technical resources for better support. A new model for coordinated private sector partnership in response to space sciences and education has been discussed. In depth analysis and techniques need to connect these pioneering communities with the space industry as well as the space governmental agencies, with special emphasis on financial constraints. The paper mandates its role to promote the use of space-based information; its established networks bringing together national institutions responsible for these space based activities, as well as other end users, and space solution experts; and its technical foundation, particularly in the area of information technologies. To help building a tighter cooperation and further understanding among all these communities, paper delivers an intensive report and solutions for future

  15. Fibre-Optic Gyroscope

    Directory of Open Access Journals (Sweden)

    V. N. Saxena

    1983-04-01

    Full Text Available Comparative study of mechanical, ring-laser and fibre-optic gyroscopes has been made. The single mode fibre-optic gyroscope having a large number of turns of the optical fibre in the spool, replacing He-Ne gas laser by a GaAs laser diode, there by reducing the noise level, and using fully integrated fibre-optics, works out to be the best in the final analysis, for safe navigation and homing of the guided missiles.

  16. Government Information Quarterly. Volume 7, no. 2: National Aeronautics and Space Administration Scientific and Technical Information Programs. Special issue

    Science.gov (United States)

    Hernon, Peter (Editor); Mcclure, Charles R. (Editor); Pinelli, Thomas E. (Editor)

    1990-01-01

    NASA scientific and technical information (STI) programs are discussed. Topics include management of information in a research and development agency, the new space and Earth science information systems at NASA's archive, scientific and technical information management, and technology transfer of NASA aerospace technology to other industries.

  17. Beyond Evidence: A Critical Appraisal of Global Warming as a Socio-Scientific Issue and a Reflection on the Changing Nature of Scientific Literacy in School

    Science.gov (United States)

    Colucci-Gray, L.

    2014-01-01

    Tom G. K. Bryce and Stephen P. Day's (2013) original article on scepticism and doubt in science education explores the context of citizens' attitudes towards the complexities and uncertainties of global issues, namely global warming. This response aims to stimulate reflection on some of the implicit assumptions underpinning the…

  18. Beyond Evidence: A Critical Appraisal of Global Warming as a Socio-Scientific Issue and a Reflection on the Changing Nature of Scientific Literacy in School

    Science.gov (United States)

    Colucci-Gray, L.

    2014-01-01

    Tom G. K. Bryce and Stephen P. Day's (2013) original article on scepticism and doubt in science education explores the context of citizens' attitudes towards the complexities and uncertainties of global issues, namely global warming. This response aims to stimulate reflection on some of the implicit assumptions underpinning the…

  19. Microstructured polymer optical fibres

    CERN Document Server

    Large, Maryanne; Barton, Geoff; van Eijkelenborg, Martijn A

    2008-01-01

    Microstructured Polymer Optical Fibres describes the optical properties of microstructured fibres, how they are made and modelled, and outlines some potential applications. These applications include areas where polymer fibres are already used, such as high-data rate transmission for Fibre-to-the Home or within cars, as well as completely new areas such as the photonic bandgap transmission of ""difficult"" wavelengths. Emphasising a conceptual understanding of the underlying physics, Microstructured Polymer Optical Fibres is clearly written, and includes numerous illustrations. It provides an

  20. Fibre illumination system

    DEFF Research Database (Denmark)

    2012-01-01

    Source: EP2426402A The invention relates to a fibre illumination module and system for the collection and delivery of daylight for illumination purposes. The fibre illumination module comprises a plurality of collector elements, each collector element comprising an input fibre having a first end......-directional arrangement. The fibre illumination system comprises a fibre illumination module of the above-mentioned type. By the invention, daylight may be exploited for the illumination of remote interior spaces of buildings in order to save energy, and improve the well-being of users in both housing and working...

  1. Beyond evidence: a critical appraisal of global warming as a socio-scientific issue and a reflection on the changing nature of scientific literacy in school

    Science.gov (United States)

    Colucci-Gray, L.

    2014-09-01

    Tom G. K. Bryce and Stephen P. Day's (2013) original article on scepticism and doubt in science education explores the context of citizens' attitudes towards the complexities and uncertainties of global issues, namely global warming. This response aims to stimulate reflection on some of the implicit assumptions underpinning the relationships between science, technology and the public. I argue that an underestimation of the political and ethical dimensions of science and technology limits the possibilities for education to set the agenda for citizens' participation in science and technological matters. Drawing on Sheila Jasanoff's model of co-production, this paper proposes a radical re-affirmation of the aims and purposes of science education to embrace a multiplicity of disciplines, narratives and ways of knowing in science, technology and society issues.

  2. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of health claims related to oat and barley grain fibre and increase in faecal bulk (ID 819, 822) pursuant to Article 13(1) of Regulation (EC) No 1924/2006

    DEFF Research Database (Denmark)

    Tetens, Inge

    Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies was asked to provide a scientific opinion on a list of health claims pursuant to Article 13 of Regulation (EC) No 1924/2006. This opinion addresses the scientific substantiation of health...... claims in relation to oat and barley grain fibre and increase in faecal bulk. The scientific substantiation is based on the information provided by the Member States in the consolidated list of Article 13 health claims and references that EFSA has received from Member States or directly from stakeholders....... In the context of the clarifications provided by Member States and the references provided, the Panel assumes that the claimed effect refers to the improvement of bowel function by increasing faecal bulk. The Panel considers that an increase in faecal bulk may be a beneficial physiological effect. In weighing...

  3. Fibres For Sensors

    Science.gov (United States)

    Payne, D. N.

    1984-11-01

    Sensors which rely on the external modulation of the properties of an optical fibre (intrinsic sensors) are receiving much attention since they can be made extremely sensitive, and can be used for distributed measurements. Distributed sensing provides some particularly exciting prospects for acoustic, magnetic and electric field monitoring. To date, however, the great majority of experimental and commercial fibre sensors employ telecommunications-grade fibres, largely as a result of their ready availability. Not only does this policy frequently lead to a design compromise, but in some cases makes the performance marginal or untenable as a result of excessive environmental sensitivity. Despite this, little attention has been given to the design of special sensor fibres with enhanced (or depressed) sensitivity to specific measurands. The position is somewhat better with respect to fibres designed to eliminate sensor polarisation problems (e.g. polar isation-maintaining fibres), but even here further work is required to provide the performance demanded.

  4. Elementary School Students' Emotions When Exploring an Authentic Socio-Scientific Issue through the Use of Models

    Science.gov (United States)

    Nicolaou, Chr. Th.; Evagorou, M.; Lymbouridou, Chr.

    2015-01-01

    Despite the belief that emotions are important in the learning process, research in the area of emotions and learning, especially in science, is scant. Modelling and SSI argumentation have shared with respect to the emphasis in recent science standards reports as core scientific practices that need to be part of science teaching and learning. Even…

  5. Mineral fibres and cancer.

    Science.gov (United States)

    McDonald, J C

    1984-04-01

    A synthesis is presented of the salient findings to date from laboratory and epidemiological research, on the health effects of asbestos and other natural and man-made mineral fibres. Experimental evidence suggests that all mineral fibres are capable of causing fibrosis and malignancy, with chrysotile at least as pathogenic as other fibres. However, penetration, retention and phagocytosis are affected by size and shape and reactivity and durability by physico-chemical properties. Thus it is not surprising that in man the results of exposure vary considerably with fibre type and industrial process. A considerable body of evidence suggests that chrysotile has seldom, if ever, caused peritoneal mesothelioma and that the great majority of pleural mesotheliomas are also attributable to crocidolite or amosite. Without more reliable information on intensity and duration of exposure by fibre type, the epidemiological evidence on this point cannot be wholly conclusive. There are stronger grounds from a limited number of cohort studies for believing that in relation to estimated exposure, the risk of lung cancer has been much higher in textile plants than in fibre production or in the manufacture of friction products, with asbestos-cement plants somewhere in between. The data on man-made fibre production remains equivocal. It is concluded that attempts to regulate asbestos without regard for fibre type, although perhaps adequate for lung cancer and fibrosis, may do little to reduce the risk of mesothelioma. The search for safe fibre substitutes for asbestos will remain difficult until the parameters of pathogenicity are better understood.

  6. Fibre illumination system

    DEFF Research Database (Denmark)

    2012-01-01

    Source: EP2426402A The invention relates to a fibre illumination module and system for the collection and delivery of daylight for illumination purposes. The fibre illumination module comprises a plurality of collector elements, each collector element comprising an input fibre having a first end...... the proximal end of the collection optics into the first end of the input fibre, each collector element having a principal axis for the collection of light defining an optical axis of the collector element. The optical axes of the collector elements are arranged in a radially outward pointing multi...

  7. SALIENT FEATURES OF BAMBOO FIBRE

    Institute of Scientific and Technical Information of China (English)

    Subrata; Das

    2007-01-01

    Bamboo fibre is a regenerated cellulosic fibre produced from bamboo.Starchy pulp is produced from bamboo stems and leaves through a process of alkaline hydrolysis and multi- phase bleaching.Further chemical processes produce bamboo fibre.

  8. SALIENT FEATURES OF BAMBOO FIBRE

    Institute of Scientific and Technical Information of China (English)

    Subrata Das

    2007-01-01

    @@ Bamboo fibre is a regenerated cellulosic fibre produced from bamboo. Starchy pulp is produced from bamboo stems and leaves through a process of alkaline hydrolysis and multiphase bleaching. Further chemical processes produce bamboo fibre.

  9. Scanners for the quality contol of scintillating plastic fibres

    CERN Document Server

    Rodigues, Ana Barbara; Garnier, Francois; Giudici, Pierre-Ange; Greim, Roman; Hebler, Philip; Joram, Christian; Kirn, Thomas; Pierschel, Gerhard; Schateikis, Tobias; Stevens, Holger; Bachlechner, Andreas; Deckenhoff, Mirco; Karpinski, Waclaw; Kruse, Florian; Schultz Von Dratzig, Arndt; Schwering, Georg; Swientek, Krzysztof Piotr; Wlochal, Michael

    2015-01-01

    The use of scintillating plastic fibres in the SciFi tracker requires rigorous quality control. The fibre diameter and in particular local variations in form of bumps and necks have an impact on the regularity of the winding pattern and hence the spatial resolution. Defects in the fibre cladding lead to light losses and inter-fibre cross talk. Machines have been developed which allow scanning at high throughput of the fibre diameter and the integrity of the cladding. We describe the design principles and implementations of these machines and illustrate their performance. While these machines allow to identify and quantify performance issues of the prototype fibres, they will also play a major role during the series production of the SciFi tracker. If needed, the capacity of the machines allows scanning of the full production volume.

  10. Laser acceleration... now with added fibre

    CERN Document Server

    Katarina Anthony

    2012-01-01

    Laser acceleration technology is plagued by two main issues: efficiency and repetition rates. In other words, lasers consume too much power and cannot sustain accelerating particles long enough to produce collisions. ICAN, a new EU-funded project, is examining how fibre lasers may help physicists tackle these issues.   A diode-pumped fibre laser. (Image courtesy of Laser Zentrum Hannover.) The International Coherent Amplification Network (ICAN) is studying the potential of lasers for collision physics. CERN is a beneficiary of the project and will collaborate with 15 other institutes from around the world, including KEK in Japan, Fermilab in the USA, and DESY in Germany. “The network is looking into existing fibre laser technology, which we believe has fantastic potential for accelerators,” says Gerard Mourou, ICAN co-ordinator at the École Polytechnique in France. “The hope is to make laser acceleration competitive with traditional radio-fre...

  11. Strength and toughness of structural fibres for composite material reinforcement.

    Science.gov (United States)

    Herráez, M; Fernández, A; Lopes, C S; González, C

    2016-07-13

    The characterization of the strength and fracture toughness of three common structural fibres, E-glass, AS4 carbon and Kevlar KM2, is presented in this work. The notched specimens were prepared by means of selective carving of individual fibres by means of the focused ion beam. A straight-fronted edge notch was introduced in a plane perpendicular to the fibre axis, with the relative notch depth being a0/D≈0.1 and the notch radius at the tip approximately 50 nm. The selection of the appropriate beam current during milling operations was performed to avoid to as much as possible any microstructural changes owing to ion impingement. Both notched and un-notched fibres were submitted to uniaxial tensile tests up to failure. The strength of the un-notched fibres was characterized in terms of the Weibull statistics, whereas the residual strength of the notched fibres was used to determine their apparent toughness. To this end, the stress intensity factor of a fronted edge crack was computed by means of the finite-element method for different crack lengths. The experimental results agreed with those reported in the literature for polyacrylonitrile-based carbon fibres obtained by using similar techniques. After mechanical testing, the fracture surface of the fibres was analysed to ascertain the failure mechanisms. It was found that AS4 carbon and E-glass fibres presented the lower toughness with fracture surfaces perpendicular to the fibre axis, emanating from the notch tip. The fractured region of Kevlar KM2 fibres extended along the fibre and showed large permanent deformation, which explains their higher degree of toughness when compared with carbon and glass fibres. This article is part of the themed issue 'Multiscale modelling of the structural integrity of composite materials'.

  12. Fibre reinforced polymer nanocomposites

    NARCIS (Netherlands)

    Vlasveld, D.P.N.

    2005-01-01

    In this thesis the results are described of the research on a combination of two types of composites: thermoplastic nanocomposites and continuous fibre composites. In this three-phase composite the main reinforcing phase are continuous glass or carbon fibres, and the matrix consists of a polyamide 6

  13. POLARISATION PRESERVING OPTICAL FIBRE

    DEFF Research Database (Denmark)

    2000-01-01

    . This cladding structure provides polarisation preserving properties to the optical fibre. Optical fibres using this technology may have claddings with elements placed non-periodically as well as in a two-dimensional periodic lattice - such as cladding providing Photonic Band Gap (PBG) effects....

  14. Chalcogenide Fibre Displacement Sensor

    Science.gov (United States)

    2001-06-01

    Fibre optic technology offers the possibility for developing of a variety of physical sensors for a wide range of physical parameters. The main...integrating sphere. The use of chalcogenide rather quartz fibre optic highly increases the Sensitivity of the sensor. Experimental set-up, transmission characteristics and technical parameters are presented.

  15. The Reasoned Arguments of a Group of Future Biotechnology Technicians on a Controversial Socio-Scientific Issue: Human Gene Therapy

    Science.gov (United States)

    Simonneaux, Laurence; Chouchane, Habib

    2011-01-01

    We tried to determine the reasoning behind the stances taken by a group of 19-21-year-old students on the controversial issue of the feasibility and acceptability of human gene therapy. The students were in training at a biotechnology institute. We organised classroom debates, punctuated by phases of epistemological "disturbances". We…

  16. Photonic Crystal Fibres

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Broeng, Jes; Sanchez Bjarklev, Araceli

    Photonic crystal fibres represent one of the most active research areas today in the field of optics. The diversity of applications that may be addressed by these fibres and their fundamental appeal, by opening up the possibility of guiding light in a radically new way compared to conventional...... optical fibres, have spun an interest from almost all areas of optics and photonics. The aim of this book is to provide an understanding of the different types of photonic crystal fibres and to outline some of the many new and exciting applications that these fibres offer. The book is intended for both...... readers with a general interest in photonic crystals, as well as for scientists who are entering the field and desire a broad overview as well as a solid starting point for further specialized stuides. Teh book, therefore, covers bothe general aspects such as the link from classical optics to photonic...

  17. Photonic Crystal Fibres

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Broeng, Jes; Sanchez Bjarklev, Araceli

    Photonic crystal fibres represent one of the most active research areas today in the field of optics. The diversity of applications that may be addressed by these fibres and their fundamental appeal, by opening up the possibility of guiding light in a radically new way compared to conventional...... optical fibres, have spun an interest from almost all areas of optics and photonics. The aim of this book is to provide an understanding of the different types of photonic crystal fibres and to outline some of the many new and exciting applications that these fibres offer. The book is intended for both...... readers with a general interest in photonic crystals, as well as for scientists who are entering the field and desire a broad overview as well as a solid starting point for further specialized stuides. Teh book, therefore, covers bothe general aspects such as the link from classical optics to photonic...

  18. EDITORIAL: Optical Fibre Sensors 18 (OFS-18)

    Science.gov (United States)

    Jones, Julian D. C.; Tatam, Ralph P.

    2007-10-01

    The International Conference on Optical Fibre Sensors (OFS-18) was held in October 2006 in Cancún, Mexico, under the general chairmanship of Dr Alexis Mendez (MCH Engineering LLC, USA) and Dr Fernando Mendoza (Centro de Investigaciones en Optica, Mexico). 'OFS', as it has become known, is firmly established as the leading international conference for the optical fibre sensor community. Since its inception, in London in 1983, and under the leadership of an international steering committee independent of any learned society or professional institution, it has been held approximately every eighteen months. The venue nominally rotates from Europe, to the Americas, and thence to Asia and the Pacific. OFS-18 demonstrated the continuing vigour of the community, with some 250 papers presented, plus two workshops, with attendance as international as ever. In recent years, it has become a tradition to publish a post-conference special issue in the journal Measurement Science and Technology, and these special issues offer a representative sample of the current status of the field. In the nearly 25 years since OFS began, many of the early ideas and laboratory-based proof-of-principle experiments have led to highly developed instrumentation systems, and to successful commercial products. Perhaps the most mature of all of these technologies is the optical fibre gyroscope, with the fibre hydrophone a close second—originally developed for defence applications for which it is now established, but with increasing relevance to the oil and gas industry; electromagnetic sensors based on the Faraday and electro-optic effects are of growing significance in the power generation and distribution industry; whilst in-fibre grating-based sensors occupy an expanding niche in structural monitoring, especially in civil engineering. It is therefore appropriate that the first day of OFS was devoted to workshops on structural health monitoring, and to commemorate the 30th anniversary of the

  19. Scientific and ethical issues related to stem cell research and interventions in neurodegenerative disorders of the brain.

    Science.gov (United States)

    Barker, Roger A; de Beaufort, Inez

    2013-11-01

    Should patients with Parkinson's disease participate in research involving stem cell treatments? Are induced pluripotent stem cells (iPSC) the ethical solution to the moral issues regarding embryonic stem cells? How can we adapt trial designs to best assess small numbers of patients in receipt of invasive experimental therapies? Over the last 20 years there has been a revolution in our ability to make stem cells from different sources and use them for therapeutic gain in disorders of the brain. These cells, which are defined by their capacity to proliferate indefinitely as well as differentiate into selective phenotypic cell types, are viewed as being especially attractive for studying disease processes and for grafting in patients with chronic incurable neurodegenerative disorders of the CNS such as Parkinson's disease (PD). In this review we briefly discuss and summarise where our understanding of stem cell biology has taken us relative to the clinic and patients, before dealing with some of the major ethical issues that work of this nature generates. This includes issues to do with the source of the cells, their ownership and exploitation along with questions about patient recruitment, consent and trial design when they translate to the clinic for therapeutic use.

  20. Scepticism and doubt in science and science education: the complexity of global warming as a socio-scientific issue

    Science.gov (United States)

    Bryce, Tom G. K.; Day, Stephen P.

    2014-09-01

    This article looks critically at the complexity of the debate among climate scientists; the controversies in the science of global temperature measurement; and at the role played by consensus. It highlights the conflicting perspectives figuring in the mass media concerned with climate change, arguing that science teachers should be familiar with them, particularly given the sharply contested views likely to be brought into classroom discussion and the importance of developing intellectual scepticism and robust scientific literacy in students. We distinguish between rational scepticism and the pejorative meaning of the expression associated with attitudinal opposition to global warming—similar to the way in which Bauer (2006) contrasts micro- scepticism and macro- scepticism in reasoning generally. And we look closely and critically at the approaches which teachers might adopt in practice to teach about global warming at this difficult time.

  1. Moiré Fibre Bragg Grating Written on Strained Fibres

    Institute of Scientific and Technical Information of China (English)

    孙磊; 冯新焕; 刘艳格; 张伟刚; 袁树忠; 开桂云; 董孝义

    2004-01-01

    Moiré fibre Bragg gratings are made in a single mode fibre and a polarization-maintaining fibre respectively, using an excimer KrF laser and a phase mask. Two gratings are written at the same location of the optical fibre. The wavelength spacing can be finely tuned from 0 to 1.86nm by straining the optical fibre during UV illumination.

  2. The hygroscopic behavior of plant fibres: a review

    Science.gov (United States)

    Célino, Amandine; Freour, Sylvain; Jacquemin, Frederic; Casari, Pascal

    2013-12-01

    Environmental concern has resulted in a renewed interest in bio-based materials. Among them, plant fibres are perceived as an environmentally friendly substitute to glass fibres for the reinforcement of composites, particularly in automotive engineering. Due to their wide availability, low cost, low density, high-specific mechanical properties and eco-friendly image, they are increasingly being employed as reinforcements in polymer matrix composites. Indeed, their complex microstructure as a composite material makes plant fibre a really interesting and challenging subject to study. Research subjects about such fibres are abundant because there are always some issues to prevent their use at large scale (poor adhesion, variability, low thermal resistance, hydrophilic behavior). The choice of natural fibres rather than glass fibres as filler yields a change of the final properties of the composite. One of the most relevant differences between the two kinds of fibre is their response to humidity. Actually, glass fibres are considered as hydrophobic whereas plant fibres have a pronounced hydrophilic behavior. Composite materials are often submitted to variable climatic conditions during their lifetime, including unsteady hygroscopic conditions. However, in humid conditions, strong hydrophilic behaviour of such reinforcing fibres leads to high level of moisture absorption in wet environments. This results in the structural modification of the fibres and an evolution of their mechanical properties together with the composites in which they are fitted in. Thereby, the understanding of these moisture absorption mechanisms as well as the influence of water on the final properties of these fibres and their composites is of great interest to get a better control of such new biomaterials. This is the topic of this review paper.

  3. The hygroscopic behavior of plant fibres: a review

    Directory of Open Access Journals (Sweden)

    Amandine eCélino

    2014-01-01

    Full Text Available Environmental concern has resulted in a renewed interest in bio-based materials. Among them, plant fibres are perceived as an environmentally friendly substitute to glass fibres for the reinforcement of composites, particularly in automotive engineering. Due to their wide availability, low cost, low density, high-specific mechanical properties and eco-friendly image, they are increasingly being employed as reinforcements in polymer matrix composites. Indeed, their complex microstructure as a composite material makes plant fibre a really interesting and challenging subject to study. Research subjects about such fibres are abundant because there are always some issues to prevent their use at large scale (poor adhesion, variability, low thermal resistance, hydrophilic behavior. The choice of natural fibres rather than glass fibres as filler yields a change of the final properties of the composite. One of the most relevant differences between the two kinds of fibre is their response to humidity. Actually, glass fibres are considered as hydrophobic whereas plant fibres have a pronounced hydrophilic behavior. Composite materials are often submitted to variable climatic conditions during their lifetime, including unsteady hygroscopic conditions. However, in humid conditions, strong hydrophilic behaviour of such reinforcing fibres leads to high level of moisture absorption in wet environments. This results in the structural modification of the fibres and an evolution of their mechanical properties together with the composites in which they are fitted in. Thereby, the understanding of these moisture absorption mechanisms as well as the influence of water on the final properties of these fibres and their composites is of great interest to get a better control of such new biomaterials. This is the topic of this review paper.

  4. Sports and exercise-related tendinopathies: a review of selected topical issues by participants of the second International Scientific Tendinopathy Symposium (ISTS) Vancouver 2012

    Science.gov (United States)

    Scott, Alex; Docking, Sean; Vicenzino, Bill; Alfredson, Håkan; Zwerver, Johannes; Lundgreen, Kirsten; Finlay, Oliver; Pollock, Noel; Cook, Jill L; Fearon, Angela; Purdam, Craig R; Hoens, Alison; Rees, Jonathan D; Goetz, Thomas J; Danielson, Patrik

    2013-01-01

    In September 2010, the first International Scientific Tendinopathy Symposium (ISTS) was held in Umeå, Sweden, to establish a forum for original scientific and clinical insights in this growing field of clinical research and practice. The second ISTS was organised by the same group and held in Vancouver, Canada, in September 2012. This symposium was preceded by a round-table meeting in which the participants engaged in focused discussions, resulting in the following overview of tendinopathy clinical and research issues. This paper is a narrative review and summary developed during and after the second ISTS. The document is designed to highlight some key issues raised at ISTS 2012, and to integrate them into a shared conceptual framework. It should be considered an update and a signposting document rather than a comprehensive review. The document is developed for use by physiotherapists, physicians, athletic trainers, massage therapists and other health professionals as well as team coaches and strength/conditioning managers involved in care of sportspeople or workers with tendinopathy. PMID:23584762

  5. Ethical and regulatory issues with conducting sexuality research with LGBT adolescents: a call to action for a scientifically informed approach.

    Science.gov (United States)

    Mustanski, Brian

    2011-08-01

    Lesbian, gay, bisexual, and transgender (LGBT) adolescents experience disparities in mental and sexual health. There is also a lack of research on this population relative to other adolescents, which limits our ability to effectively address these health disparities. Researchers may unfortunately avoid conducting research with this population because of anticipated or actual experiences with difficulties in obtaining IRB approval. A case example is provided to illustrate the ethical and regulatory issues related to research with LGBT adolescents. Relevant U.S. federal and local regulations related to research on sexual and mental health with adolescents is then reviewed. Data are presented demonstrating that requiring parental consent for LGBT youth under age 18 would likely alter study result. Data are also presented on participants' appraisals of the risks and discomforts associated with research participation. The provision of such empirical data on the risks of research participation is consistent with the goal of moving the IRB process of risk/benefit assessment from being entirely subjective to being evidence-based. Finally, recommendations are provided on how to approach these issues in IRB applications and investigators are called to help to build a corpus of scholarship that can advance empirical knowledge in this area.

  6. Issues for SME Credit Information DB Institutionsand Expectations for the Econophysics ---Scientific Economic Policies for Avoiding Moral Hazard---

    Science.gov (United States)

    Tanabe, T.

    The CRD database, which has been accumulating financial data on SMEsover the ten years since its founding, and has gathered approximately 12 million records for around 2 million SMEs, approximately 3 million records for somewhere around 900,000 sole proprietors, also collected default data on these companies and sole proprietors. The CRD database's weakness is anonymity. Going forward, therefore, it appears the CRD Association is faced with questions concerning how it will enhance the attractiveness of its database whether new knowledge should be gained by using econophysics or other research approaches. We have already seen several examples of knowledge gained through econophysical analyses using the CRD database, and I would like to express my hope that we will eventually see greater application of the SME credit information database and econophysical analysis for the development of Japans SME policies which are scientific economic policies for avoiding moral hazard, and will expect elucidating risk scenarios for the global financial, natural disaster, and other shocks expected to happen with greater frequency. Therefore, the role played by econophysics will become increasingly important, and we have high expectations for the role to be played by the field of econophysics.

  7. SAP Minutes No.2015-03 for FIFRA meeting held 9/15-17/2015. A set of scientific issues being considered by the Environmental Protection Agency regarding development of a spatial aquatic model(SAM)for pesticide risk assessment

    Science.gov (United States)

    On September 15-17th, 2014, the US Environmental Protection Agency convened a public meeting of the FIFRA Scientific Advisory Panel (SAP) to address scientific issues associated with the agency’s “Development of a Spatial Aquatic Model (SAM) for Pesticide Risk Assessment”. The goal of SAM is to impr...

  8. Fibre illumination system

    DEFF Research Database (Denmark)

    2012-01-01

    the proximal end of the collection optics into the first end of the input fibre, each collector element having a principal axis for the collection of light defining an optical axis of the collector element. The optical axes of the collector elements are arranged in a radially outward pointing multi......Source: EP2426402A The invention relates to a fibre illumination module and system for the collection and delivery of daylight for illumination purposes. The fibre illumination module comprises a plurality of collector elements, each collector element comprising an input fibre having a first end...... and a second end, and a collection optics, the collection optics being configured to receive light incident on a distal end of the collection optics, to transfer at least partially the incident light to a proximal end of the collection optics, and to couple at least partially the transferred light from...

  9. D fibre antenna for microcellular communications

    Energy Technology Data Exchange (ETDEWEB)

    Bhatti, Ajaz

    2003-07-01

    Over the years, optical fibre sensors have been developed for many application areas. With the recent growth of microcellular communication systems this area has great economic potential. Therefore with this in mind one promising application for a new optical fibre sensor system is in the detection of Radio Frequency/Electric Fields (RF/EF). By constructing such a sensor from totally dielectric materials, it could be used as an antenna for receiving radio frequency transmissions without distorting or disturbing the field lines since there are no metallic components to reflect or transmit radio frequency energy. One of the key issues in the realisation of Radio-over-Fibre (RoF) architecture is the development of an effective means of generating and transmitting the radio subcarrier. The simplest method for the optical generation of radio signals, for transmission through an optical network is to directly modulate the light source with the received RF signal. Direct modulation of the laser can lead to a number of problems such as relative intensity noise (RIN), chirp and intermodulation distortion (IMD). A novel approach as described in this thesis, for generating an externally modulated optical signal would be to use an optical antenna comprising of a piezoelectric polymer coated D-fibre configured within a Mach-Zehnder interferometer to phase modulate the lightwave with a received RF electrical signal. One of the primary advantages of the D-fibre antenna over conventional antennae is its ability to serve a dual purpose. First it can be used to directly detect the RF signal, and secondly it provides a convenient means for modulating the light within the fibre thus bypassing the need for directly modulating the laser. The work presented in this thesis forms a comprehensive study on the design and modelling of a novel all-optical antenna using D-shaped optical fibre for use in next generation RoF networks. For the first time Finite Element Analysis (FEA) has been used

  10. Understanding and Improving the Elastic Compressive Modulus of Fibre Reinforced Soy-Based Polyurethane Foams

    Science.gov (United States)

    Hussain, Sadakat

    Soy-based polyurethane foams (PUFs) were reinforced with fibres of different aspect ratios to improve the compressive modulus. Each of the three fibre types reinforced PUF differently. Shorter micro-crystalline cellulose fibres were found embedded inside the cell struts of PUF and reinforced them. The reinforcement was attributed to be stress transfer from the matrix to the fibre by comparing the experimental results to those predicted by micro-mechanical models for short fibre reinforced composites. The reinforced cell struts increased the overall compressive modulus of the foam. Longer glass fibres (470 microns, length) provided the best reinforcement. These fibres were found to be larger than the cell diameters. The micro-mechanical models could not predict the reinforcement provided by the longer glass fibres. The models predicted negligible reinforcement because the very low modulus PUF should not transfer load to the higher modulus fibres. However, using a finite element model, it was determined that the fibres were providing reinforcement through direct fibre interaction with each other. Intermediate length glass fibres (260 microns, length) were found to poorly reinforce the PUF and should be avoided. These fibres were too short to interact with each other and were on average too large to embed and reinforce cell struts. In order to produce natural fibre reinforced PUFs in the future, a novel device was invented. The purpose of the device is to deliver natural fibres at a constant mass flow rate. The device was found to consistently meter individual loose natural fibre tufts at a mass flow rate of 2 grams per second. However, the device is not robust and requires further development to deliver a fine stream of natural fibre that can mix and interact with the curing polymeric components of PUF. A design plan was proposed to address the remaining issues with the device.

  11. Determining the fibrillar orientation of bast fibres with polarized light microscopy: the modified Herzog test (red plate test) explained.

    Science.gov (United States)

    Haugan, E; Holst, B

    2013-11-01

    The identification of bast fibre samples, in particular, bast fibres used in textiles, is an important issue in archaeology, criminology and other scientific fields. One of the characteristic features of bast fibres is their fibrillar orientation, referred to as Z- or S twist (or alternatively right- and left-handed fibres). An empirical test for determining the fibrillar orientation using polarized light microscopy has been known in the community for many years. It is referred to as the modified Herzog test or red plate test. The test has the reputation for never producing false results, but also for occasionally not working. However, so far, no proper justification has been provided in the literature that the 'no false results' assumption is really correct and it has also not been clear up till now, why the method sometimes does not work. In this paper, we present an analytical model for the modified Herzog test, which explains why the test never gives a false result. We also provide an explanation for why the Herzog test sometimes does not work: According to our model, the Herzog test will not work if none of the three distinct layers in the secondary cell wall is significantly thicker than the others.

  12. Determining the fibrillar orientation of bast fibres with polarized light microscopy: the modified Herzog test (red plate test) explained

    Science.gov (United States)

    HAUGAN, E; HOLST, B

    2013-01-01

    The identification of bast fibre samples, in particular, bast fibres used in textiles, is an important issue in archaeology, criminology and other scientific fields. One of the characteristic features of bast fibres is their fibrillar orientation, referred to as Z- or S twist (or alternatively right- and left-handed fibres). An empirical test for determining the fibrillar orientation using polarized light microscopy has been known in the community for many years. It is referred to as the modified Herzog test or red plate test. The test has the reputation for never producing false results, but also for occasionally not working. However, so far, no proper justification has been provided in the literature that the ‘no false results’ assumption is really correct and it has also not been clear up till now, why the method sometimes does not work. In this paper, we present an analytical model for the modified Herzog test, which explains why the test never gives a false result. We also provide an explanation for why the Herzog test sometimes does not work: According to our model, the Herzog test will not work if none of the three distinct layers in the secondary cell wall is significantly thicker than the others. PMID:24020614

  13. The Relationship of Science Knowledge, Attitude and Decision Making on Socio-Scientific Issues: The Case Study of Students' Debates on a Nuclear Power Plant in Korea

    Science.gov (United States)

    Jho, Hunkoog; Yoon, Hye-Gyoung; Kim, Mijung

    2014-01-01

    The purpose of this study was to investigate the relationship of students' understanding of science knowledge, attitude and decision making on socio-scientific issues (SSI), especially on the issues of nuclear energy in Korea. SSI-focused instructions were developed to encourage students to understand and reflect on knowledge, attitude and…

  14. Exploring the scientific method: cases and questions

    National Research Council Canada - National Science Library

    Gimbel, Steven

    2011-01-01

    Exploring the scientific method pairs classic and contemporary readings in the philosophy of science with milestones in scientific discovery to illustrate the foundational issues underlying scientific methodology...

  15. Multibeam Fibre Laser Cutting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove

    The appearance of the high power high brilliance fibre laser has opened for new possibilities in laser materials processing. In laser cutting this laser has demonstrated high cutting performance compared to the dominating cutting laser, the CO2-laser. However, quality problems in fibre-laser...... cutting have until now limited its application in metal cutting. In this paper the first results of proof-of-principle studies applying a new approach (patent pending) for laser cutting with high brightness short wavelength lasers will be presented. In the approach, multi beam patterns are applied...... to control the melt flow out of the cut kerf resulting in improved cut quality in metal cutting. The beam patterns in this study are created by splitting up beams from 2 single mode fibre lasers and combining these beams into a pattern in the cut kerf. The results are obtained with a total of 550 W of single...

  16. Raw Materials in Fibre Enriched Biscuits Production as Source of Total Phenols

    Directory of Open Access Journals (Sweden)

    Blaženka Šebečić

    2007-09-01

    Full Text Available Due to scientifically well documented health beneficial effects of dietary fibres and recommendations for an every day intake on an average of 30 g by food (DRI 2005, the confectionery industry has been increasingly engaged in the production of fibre enriched biscuits with the aim to offer such a product as a valuable constituent of proper nutrition and dietetic functional food intended for risky populations. Thereby, commercially available pure fibres or fibre-rich raw materials have been used for the enrichment of biscuits, prevalently pure fibres. To evaluate such products as functional food it is of interest to know how the choice of raw material for biscuit fibre enrichment influences the content of other health protecting compounds which commonly accompany fibres in plant material. With the aim of evaluating fibre rich biscuits as a source of total phenols depending on the origin of fibres, total phenols were determined spectrophotometrically by a modified Folin-Ciocalteau method (Gao et al. 2002 in ten experimentally baked biscuits based on wheat flour type 500 and type 1700 with or without different dietary fibres or fibre rich raw materials added instead of definite amount of white fl our. Results show that shares of total phenols and fibres in biscuits based on the wheat fl our depend on the type of the fl our. Biscuits with pure wheat and oats fibres added were the lowest in phenol content regardless on the highest amount of fibres (0.96 g kg-1 and 1.09 g kg-1, respectively; inulin and amaranth do not changeessentially phenol content; apple fibres, soya fl our, and carob fl our enhance phenol content thereby carob fl our being the most effective giving biscuits 5.53 g total phenols kg-1.

  17. Raw Materials in Fibre Enriched Biscuits Production as Source of Total Phenols

    Directory of Open Access Journals (Sweden)

    Blaženka Šebečić

    2007-09-01

    Full Text Available Due to scientifically well documented health beneficial effects of dietary fibres and recommendations for an every day intake on an average of 30 g by food (DRI 2005, the confectionery industry has been increasingly engaged in the production of fibre enriched biscuits with the aim to offer such a product as a valuable constituent of proper nutrition and dietetic functional food intended for risky populations. Thereby, commercially available pure fibres or fibre-rich raw materials have been used for the enrichment of biscuits, prevalently pure fibres. To evaluate such products as functional food it is of interest to know how the choice of raw material for biscuit fibre enrichment influences the content of other health protecting compounds which commonly accompany fibres in plant material. With the aim of evaluating fibre rich biscuits as a source of total phenols depending on the origin of fibres, total phenols were determined spectrophotometrically by a modified Folin-Ciocalteau method (Gao et al. 2002 in ten experimentally baked biscuits based on wheat flour type 500 and type 1700 with or without different dietary fibres or fibre rich raw materials added instead of definite amount of white fl our. Results show that shares of total phenols and fibres in biscuits based on the wheat fl our depend on the type of the fl our. Biscuits with pure wheat and oats fibres added were the lowest in phenol content regardless on the highest amount of fibres (0.96 g kg-1 and 1.09 g kg-1, respectively; inulin and amaranth do not change essentially phenol content; apple fibres, soya fl our, and carob fl our enhance phenol content thereby carob fl our being the most effective giving biscuits 5.53 g total phenols kg-1.

  18. Woven Structures from Natural Fibres for Reinforcing Composites

    OpenAIRE

    Maniņš, M; Bernava, A; Strazds, G.

    2015-01-01

    The increase of production of woven structures from natural fibres for reinforced composites can be noticed in different sectors of economy. This can be explained by limited sources of raw materials and different environmental issues, as well as European Union guidelines for car manufacture [4]. This research produced 2D textile structures of hemp yarn and polypropylene yarn and tested the impact of added glass fibre yarn on the mechanical properties of the woven structures and the composites...

  19. Extraction of nanocellulose fibrils from lignocellulosic fibres: a novel approach

    CSIR Research Space (South Africa)

    Abraham, E

    2011-06-01

    Full Text Available -1 Carbohydrate Polymers Volume 86, Issue 4, 15 October 2011, Pages 1468-1475 Extraction of nanocellulose fibrils from lignocellulosic fibres: A novel approach E. Abrahama, B. Deepaa, L.A. Pothana, , , M. Jacobc, S. Thomasb, U. Cvelbard, R. Anandjiwalac a... Department of Chemistry, Bishop Moore College, Mavelikkara 690 101, Kerala, India b School of Chemical Sciences, Mahatma Gandhi university, Kottayam 686 560, Kerala, India c Fibres and Textiles Competence Area, CSIR, Materials Science and Manufacturing...

  20. Optical fibre line failure detecting

    OpenAIRE

    Xie, Feng

    2013-01-01

    With the development of modern communications, in order to meet the needs of social development and technological progress the optical fibre communications has become the main communication medium for its high reliability and security. Fibre-optic cable is the channel for signal transmission. It is an important component in the entire fibre-optic network. Once the fibre-optic cable fault happened, the entire communication system would be impacted seriously. When fault occurs, it is important ...

  1. Fibre Optics in Undersea Applications

    Directory of Open Access Journals (Sweden)

    A. K. Talwar

    1984-01-01

    Full Text Available Role of optical fibres for underwater communication cables and hydrophones is discussed. The fibre optics cables provide an excellent solution to the historical bandwidth-diameter problems of conventional coaxial cables.Fibre optic hydrophones are found to have many more advantages apart from high sensitivity and large dynamic range, over the classical sound sensors used in underwater work.

  2. Single-mode optical fibres

    CERN Document Server

    Cancellieri, G

    1991-01-01

    This book describes signal propagation in single-mode optical fibres for telecommunication applications. Such description is based on the analysis of field propagation, considering waveguide properties and also some of the particular characteristics of the material fibre. The book covers such recent advances as, coherent transmissions; optical amplification; MIR fibres; polarization maintaining; polarization diversity and photon counting.

  3. Orientational Distribution of Fibres in Sheared Fibre Suspensions

    Institute of Scientific and Technical Information of China (English)

    KU Xiao-Ke; LIN Jian-Zhong

    2007-01-01

    Motion of fibres in sheared fibre suspensions is simulated numerically by using the lattice Boltzmann method. The orientational distributions of the fibres are presented for different Reynolds numbers, Stokes numbers, shear rate and fibre aspect ratio. Some computational results are compared with the experimental data of pipe Bow, and the qualitative agreement is achieved. The results show that the orientational distributions are greatly affected by the Reynolds numbers, while relatively insensitive to the fibre aspect ratio. The Stokes number and shear rate have obvious influence on the orientation distribution.

  4. Dietary fibre: challenges in production and use of food composition data.

    Science.gov (United States)

    Westenbrink, Susanne; Brunt, Kommer; van der Kamp, Jan-Willem

    2013-10-01

    Dietary fibre is a heterogeneous group of components for which several definitions and analytical methods were developed over the past decades, causing confusion among users and producers of dietary fibre data in food composition databases. An overview is given of current definitions and analytical methods. Some of the issues related to maintaining dietary fibre values in food composition databases are discussed. Newly developed AOAC methods (2009.01 or modifications) yield higher dietary fibre values, due to the inclusion of low molecular weight dietary fibre and resistant starch. For food composition databases procedures need to be developed to combine 'classic' and 'new' dietary fibre values since re-analysing all foods on short notice is impossible due to financial restrictions. Standardised value documentation procedures are important to evaluate dietary fibre values from several sources before exchanging and using the data, e.g. for dietary intake research. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Fabrication of Polymer Optical Fibre (POF Gratings

    Directory of Open Access Journals (Sweden)

    Yanhua Luo

    2017-03-01

    Full Text Available Gratings inscribed in polymer optical fibre (POF have attracted remarkable interest for many potential applications due to their distinctive properties. This paper overviews the current state of fabrication of POF gratings since their first demonstration in 1999. In particular we summarize and discuss POF materials, POF photosensitivity, techniques and issues of fabricating POF gratings, as well as various types of POF gratings.

  6. Optical fibre cable selection for electricity utilities

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    The report provides an assessment of the range of optical fibre cable solutions available, by type e.g. OPGW, ADSS, rather than by design. it also examines the key issues which will influence an electricity utilities decisions and proposes a method of evaluating the options to identify the one which most closely matches the utility's critical needs, with measurements against time, cost and quality targets. (author)

  7. Glass Fibre Reinforced Polymers

    NARCIS (Netherlands)

    Nikolaou, N.; Karagianni, L.; Sarakiniatti, M.V.

    2014-01-01

    This "designers' manual" is made during the TIDO-course AR0533 Innovation & Sustainability. Fibre reinforced polymers (FRPs) have been used in many applications over the years, from new construction to retrofitting. They are lightweight, no-corrosive, exhibit high specific strength and specific

  8. Glass Fibre Reinforced Polymers

    NARCIS (Netherlands)

    Nikolaou, N.; Karagianni, L.; Sarakiniatti, M.V.

    2014-01-01

    This "designers' manual" is made during the TIDO-course AR0533 Innovation & Sustainability. Fibre reinforced polymers (FRPs) have been used in many applications over the years, from new construction to retrofitting. They are lightweight, no-corrosive, exhibit high specific strength and specific sti

  9. Modelling of photonic crystal fibres

    DEFF Research Database (Denmark)

    Knudsen, Erik

    2003-01-01

    In the presenta ph.d. work a theoretical study of aspects of modelling photonic crystal fibres was carried out. Photonic crystal fibres form a class of optical waveguides where guidance is no longer provided by a difference in refractive index between core and cladding. Instead, guidance...... is provided by an arrangement of air-holes running along the length of the fibre. Depending on the geometry of the fibre, the guiding mechanism may be either arising from the formation of a photonic bandgap in the cladding structure (photonic bandgap fibre), or by an effect resembling total internal...... modes in contiguous fibre segments curved at different radii. Overall microbend loss is expressed as a statistical mean of mismatch losses. Extending a well proven, established formula for macrobending losses in stop index fibres, we provide an estimate of macrobend losses in an air-guiding photonic...

  10. Review on hygroscopic aging of cellulose fibres and their biocomposites.

    Science.gov (United States)

    Mokhothu, Thabang H; John, Maya Jacob

    2015-10-20

    This review presents critical literature on effects of humidity and temperature on the properties of natural fibres and its composites. The drawback of moisture absorption on the mechanical properties of natural fibre and its composites is evaluated. Numerous researchers have been working to address the moisture absorption issue, with specific attention paid to the surface treatment of fibres and refining the fibre-matrix interface. Because of the natural fibre's positive commercial and environmental outcomes, as well as their desirable properties such as high specific strength, natural fibre reinforced composites are displaying a good potential to be used in various applications such as automotive, aerospace and packaging. This review addresses a comprehensive survey on hygroscopic factors (long term environmental aging) affecting natural fibres and their performance as reinforcement in polymer composites. The effects of cellulose surface chemistry and topography on hydrophobicity are addressed. Furthermore, the review also addresses the progress in the development of superhydrophobic materials based on cellulose material for better moisture resistance. In addition, recent investigations dealing with bio-based coatings prepared from renewable resources are also discussed.

  11. Optical Fibre Sensors Using Graphene-Based Materials: A Review

    Science.gov (United States)

    Hernaez, Miguel; Zamarreño, Carlos R.; Melendi-Espina, Sonia; Bird, Liam R.; Mayes, Andrew G.; Arregui, Francisco J.

    2017-01-01

    Graphene and its derivatives have become the most explored materials since Novoselov and Geim (Nobel Prize winners for Physics in 2010) achieved its isolation in 2004. The exceptional properties of graphene have attracted the attention of the scientific community from different research fields, generating high impact not only in scientific journals, but also in general-interest newspapers. Optical fibre sensing is one of the many fields that can benefit from the use of these new materials, combining the amazing morphological, chemical, optical and electrical features of graphene with the advantages that optical fibre offers over other sensing strategies. In this document, a review of the current state of the art for optical fibre sensors based on graphene materials is presented. PMID:28098825

  12. Optical Fibre Sensors Using Graphene-Based Materials: A Review

    Directory of Open Access Journals (Sweden)

    Miguel Hernaez

    2017-01-01

    Full Text Available Graphene and its derivatives have become the most explored materials since Novoselov and Geim (Nobel Prize winners for Physics in 2010 achieved its isolation in 2004. The exceptional properties of graphene have attracted the attention of the scientific community from different research fields, generating high impact not only in scientific journals, but also in general-interest newspapers. Optical fibre sensing is one of the many fields that can benefit from the use of these new materials, combining the amazing morphological, chemical, optical and electrical features of graphene with the advantages that optical fibre offers over other sensing strategies. In this document, a review of the current state of the art for optical fibre sensors based on graphene materials is presented.

  13. Life Cycle Assessment of Biobased Fibre-Reinforced Polymer Composites (Levenscyclusanalyse van biogebaseerde, vezelversterkte polymeercomposieten)

    OpenAIRE

    Deng, Yelin

    2014-01-01

    Today, global environmental issues, such as global warming and fossil depletion, drive a paradigm shift in material applications from conventional fossil sources to renewable sources. Following this trend, the topic of this thesis is to analyse the use of biobased resources for fibre reinforced composite fabrication. Currently the most widely used fibre reinforced composites are composed of glass fibre reinforcements and polymeric matrices. In this thesis, the biobased alternative, i.e. flax ...

  14. Nutritional and environmental consequences of dietary fibre in pig nutrition: A review

    OpenAIRE

    Bindelle, Jérôme; Leterme, Pascal; Buldgen, André

    2008-01-01

    Despite its negative impact on performances because of lower protein and energy digestibility, increasing attention has been paid in the past decade to dietary fibre in swine nutrition due to its multiple functionalities. The present review examines the influence of dietary fibre on the digestive processes and the consequences on pig protein and energy nutrition, health concerns and environmental issues. Dietary fibre is defined as the plant polysaccharides that are resistant to digestive...

  15. Non-Linear Fibres for Widely Tunable Femtosecond Fibre Lasers

    DEFF Research Database (Denmark)

    Pedersen, Martin Erland Vestergaard

    This Ph.D. thesis investigates how intramodal and intermodal nonlinear processes in few-moded fibres can be used to generate light sources at wavelengths outside the spectral gain-bands of rare-earth-doped opticalfibres. The design of two specialty few-moded fibres for use in a widely tunable...... femtosecond fibre laser is presented. The two fibres are used to facilitate the shifting of a soliton in a cascade configuration from the ytterbium gain-band and to a wavelength of 1280 nm. The temporal pulse duration is on a femtosecond scale with a pulse energy of 5 nJ. The experimentally observed soliton...... self-frequency shift and thereby the outcome of the experimental demonstration of the widely tunable femtosecond fibre laser is shown to depend highly on the chirped of the input pulse into the first few-moded fibre in the cascade setup. Furthermore, an alternative splicing process, with a combination...

  16. Fibre composite in driveline

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, W.

    1989-03-01

    Apart from the geometric degrees of freedom of classical material, fibre composites as material for cardan shafts offer two further free parameters to the design engineer: The fiberment winding angle and the ratio of carbon and glass fibres. This results in a large scope of characteristics in terms of flexibility and torsion. In many cases it is therefore possible to use a one-piece shaft instead of a two-piece shaft, and a specific harmonization of the vibration characteristics of the driveline can be realized. In comparison with shafts made out of steel, mass is reduced by 40-50%, the moment of inertia of the mass by 35-40%. The Composite shaft fulfils the requirements of the performance specifications typical of the components concerned both in terms of engineering and efficiency.

  17. A simplified immunohistochemical classification of skeletal muscle fibres in mouse

    Directory of Open Access Journals (Sweden)

    M. Kammoun

    2014-06-01

    Full Text Available The classification of muscle fibres is of particular interest for the study of the skeletal muscle properties in a wide range of scientific fields, especially animal phenotyping. It is therefore important to define a reliable method for classifying fibre types. The aim of this study was to establish a simplified method for the immunohistochemical classification of fibres in mouse. To carry it out, we first tested a combination of several anti myosin heavy chain (MyHC antibodies in order to choose a minimum number of antibodies to implement a semi-automatic classification. Then, we compared the classification of fibres to the MyHC electrophoretic pattern on the same samples. Only two anti MyHC antibodies on serial sections with the fluorescent labeling of the Laminin were necessary to classify properly fibre types in Tibialis Anterior and Soleus mouse muscles in normal physiological conditions. This classification was virtually identical to the classification realized by the electrophoretic separation of MyHC. This immunohistochemical classification can be applied to the total area of Tibialis Anterior and Soleus mouse muscles. Thus, we provide here a useful, simple and time-efficient method for immunohistochemical classification of fibres, applicable for research in mouse

  18. Optical Fibre Bundle

    CERN Multimedia

    These are sample fibre optic cables which are used for networking. Optical fibers are widely used in fiber-optic communications, where they permit transmission over longer distances and at higher bandwidths (data rates) than wire cables. Fibers are used instead of metal wires because signals travel along them with less loss and are also immune to electromagnetic interference. This is useful for somewhere like CERN where magnets with their highly powerful magnetic fields could pose a problem.

  19. Fibre-optical microendoscopy.

    Science.gov (United States)

    Gu, M; Bao, H; Kang, H

    2014-04-01

    Microendoscopy has been an essential tool in exploring micro/nano mechanisms in vivo due to high-quality imaging performance, compact size and flexible movement. The investigations into optical fibres, micro-scanners and miniature lens have boosted efficiencies of remote light delivery to sample site and signal collection. Given the light interaction with materials in the fluorescence imaging regime, this paper reviews two classes of compact microendoscopy based on a single fibre: linear optical microendoscopy and nonlinear optical microendoscopy. Due to the fact that fluorescence occurs only in the focal volume, nonlinear optical microendoscopy can provide stronger optical sectioning ability than linear optical microendoscopy, and is a good candidate for deep tissue imaging. Moreover, one-photon excited fluorescence microendoscopy as the linear optical microendoscopy suffers from severe photobleaching owing to the linear dependence of photobleaching rate on excitation laser power. On the contrary, nonlinear optical microendoscopy, including two-photon excited fluorescence microendoscopy and second harmonic generation microendoscopy, has the capability to minimize or avoid the photobleaching effect at a high excitation power and generate high image contrast. The combination of various nonlinear signals gained by the nonlinear optical microendoscopy provides a comprehensive insight into biophenomena in internal organs. Fibre-optical microendoscopy overcomes physical limitations of traditional microscopy and opens up a new path to achieve early cancer diagnosis and microsurgery in a minimally invasive and localized manner.

  20. Analysis of glass fibre sizing

    DEFF Research Database (Denmark)

    Petersen, Helga Nørgaard; Kusano, Yukihiro; Brøndsted, Povl

    2014-01-01

    Glass fibre reinforced polymer composites are widely used for industrial and engineering applications which include construction, aerospace, automotive and wind energy industry. During the manufacturing glass fibres, they are surface-treated with an aqueous solution. This process and the treated...... surfaces are called sizing. The sizing influences the properties of the interface between fibres and a matrix, and subsequently affects mechanical properties of composites. In this work the sizing of commercially available glass fibres was analysed so as to study the composition and chemical structures....... Soxhlet extraction was used to extract components of the sizing from the glass fibres. The glass fibres, their extracts and coated glass plates were analysed by Thermo-Gravimetric Analysis combined with a mass spectrometer (TGA-MS), and Attenuated Total Reflectance Fourier Transform Infrared (ATR...

  1. Scientific Crossbreeding

    DEFF Research Database (Denmark)

    Hvidtfeldt, Rolf

    This thesis presents an alternative approach to the analysis of interdisciplinarity. One of the basic reasons for developing an alternative method for evaluation of interdisciplinary activities is that epistemic issues are insufficiently dealt with in the existing literature on the topic. To deve......This thesis presents an alternative approach to the analysis of interdisciplinarity. One of the basic reasons for developing an alternative method for evaluation of interdisciplinary activities is that epistemic issues are insufficiently dealt with in the existing literature on the topic....... To develop a more adequate way of capturing what is at stake in interdisciplinarity, I suggest drawing inspiration from the contemporary philosophical literature on scientific representation. The development of a representation based approach to the analysis of interdisciplinarity, and the discussion...... of the concept of “scientific discipline” and disciplinary difference. This chapter provides reasons to assume that conventional scientific taxonomies do not provide a good basis for analysing epistemic aspects of interdisciplinary science. On this background it is argued that the concept of “approaches...

  2. Ethical and scientific issues of nanotechnology in the workplace Questões éticas e científicas sobre locais de trabalho com nanotecnologia

    Directory of Open Access Journals (Sweden)

    Paul A. Schulte

    2007-10-01

    Full Text Available In the absence of scientific clarity about the potential health effects of occupational exposure to nanoparticles, a need exists for guidance in decisionmaking about hazards, risks, and controls. An identification of the ethical issues involved may be useful to decision makers, particularly employers, workers, investors, and health authorities. Because the goal of occupational safety and health is the prevention of disease in workers, the situations that have ethical implications that most affect workers have been identified. These situations include the a identification and communication of hazards and risks by scientists, authorities, and employers; b workers' acceptance of risk; c selection and implementation of controls; d establishment of medical screening programs; and e investment in toxicologic and control research. The ethical issues involve the unbiased determination of hazards and risks, nonmaleficence (doing no harm, autonomy, justice, privacy, and promoting respect for persons. As the ethical issues are identified and explored, options for decision makers can be developed. Additionally, societal deliberations about workplace risks of nanotechnologies may be enhanced by special emphasis on small businesses and adoption of a global perspective.Na ausência de evidência quanto a potenciais efeitos da exposição a nanopartículas sobre a saúde ocupacional, existe necessidade de orientação para os gestores a respeito dos riscos, perigos e dos possíveis controles. A identificação de questões éticas envolvidas é útil, particularmente para empregadores, empregados, investidores e autoridades de saúde, uma vez que o sentido e a meta da segurança ocupacional e de saúde é a prevenção de doenças para os trabalhadores. Essa situação inclui: (a identificação e comunicação de riscos por cientistas, autoridades e empregadores; (b aceitação dos riscos por parte dos trabalhadores; (c seleção e implementação de controles

  3. Cereal fibre and type 2 diabetes: time now for randomised controlled trials?

    Science.gov (United States)

    Whincup, Peter H; Donin, Angela S

    2015-07-01

    Diet and nutrition are strongly implicated in the aetiology of type 2 diabetes; low dietary fibre intake could be an important factor. Evidence from prospective observational studies has suggested that it may be low cereal fibre intake, rather than low fruit and vegetable fibre intake, which is particularly important. In this issue of Diabetologia (DOI 10.1007/s00125-015-3585-9 ) Kuijsten et al report on the prospective associations between different dietary fibre sources and type 2 diabetes risk in the European Prospective Investigation of Cancer and Nutrition (EPIC)-Interact study and set their findings in context with a meta-analysis of relevant published prospective studies. The results presented strengthen the evidence implicating cereal fibre as an important determinant of type 2 diabetes risk and suggest that randomised controlled trials examining the effect of cereal fibre supplementation on type 2 diabetes risk are now needed.

  4. The use of potato fibre to improve bread physico-chemical properties during storage.

    Science.gov (United States)

    Curti, Elena; Carini, Eleonora; Diantom, Agoura; Vittadini, Elena

    2016-03-15

    Bread staling reduction is a very important issue for the food industry. A fibre with high water holding capacity, extracted from potato peel, was studied for its ability to reduce bread staling even if employed at low level (0.4 g fibre/100 g flour). Physico-chemical properties (water activity, moisture content, frozen water content, amylopectin retrogradation) and (1)H Nuclear Magnetic Resonance molecular mobility were characterised in potato fibre added bread over 7 days of storage. Potato fibre addition in bread slightly affected water activity and moisture content, while increased frozen water content and resulted in a softer bread crumb, more importantly when the optimal amount of water was used in the formulation. Potato fibre also reduced (1)H NMR molecular mobility changes in bread crumb during storage. Potato fibre addition in bread contributed to reduce bread staling.

  5. Sports and exercise-related tendinopathies : a review of selected topical issues by participants of the second International Scientific Tendinopathy Symposium (ISTS) Vancouver 2012

    NARCIS (Netherlands)

    Scott, Alex; Docking, Sean; Vicenzino, Bill; Alfredson, Hakan; Zwerver, Johannes; Lundgreen, Kirsten; Finlay, Oliver; Pollock, Noel; Cook, Jill L.; Fearon, Angela; Purdam, Craig R.; Hoens, Alison; Rees, Jonathan D.; Goetz, Thomas J.; Danielson, Patrik

    2013-01-01

    In September 2010, the first International Scientific Tendinopathy Symposium (ISTS) was held in Umea, Sweden, to establish a forum for original scientific and clinical insights in this growing field of clinical research and practice. The second ISTS was organised by the same group and held in Vancou

  6. Sports and exercise-related tendinopathies : a review of selected topical issues by participants of the second International Scientific Tendinopathy Symposium (ISTS) Vancouver 2012

    NARCIS (Netherlands)

    Scott, Alex; Docking, Sean; Vicenzino, Bill; Alfredson, Hakan; Zwerver, Johannes; Lundgreen, Kirsten; Finlay, Oliver; Pollock, Noel; Cook, Jill L.; Fearon, Angela; Purdam, Craig R.; Hoens, Alison; Rees, Jonathan D.; Goetz, Thomas J.; Danielson, Patrik

    In September 2010, the first International Scientific Tendinopathy Symposium (ISTS) was held in Umea, Sweden, to establish a forum for original scientific and clinical insights in this growing field of clinical research and practice. The second ISTS was organised by the same group and held in

  7. Applications for carbon fibre recovered from composites

    Science.gov (United States)

    Pickering; Liu, Z.; Turner, TA; Wong, KH

    2016-07-01

    Commercial operations to recover carbon fibre from waste composites are now developing and as more recovered fibre becomes available new applications for recovered fibre are required. Opportunities to use recovered carbon fibre as a structural reinforcement are considered involving the use of wet lay processes to produce nonwoven mats. Mats with random in-plane fibre orientation can readily be produced using existing commercial processes. However, the fibre volume fraction, and hence the mechanical properties that can be achieved, result in composites with limited mechanical properties. Fibre volume fractions of 40% can be achieved with high moulding pressures of over 100 bar, however, moulding at these pressures results in substantial fibre breakage which reduces the mean fibre length and the properties of the composite manufactured. Nonwoven mats made from aligned, short carbon fibres can achieve higher fibre volume fractions with lower fibre breakage even at high moulding pressure. A process for aligning short fibres is described and a composite of over 60% fibre volume fraction has been manufactured at a pressures up to 100 bar with low fibre breakage. Further developments of the alignment process have been undertaken and a composite of 46% fibre volume fraction has been produced moulded at a pressure of 7 bar in an autoclave, exhibiting good mechanical properties that compete with higher grade materials. This demonstrates the potential for high value applications for recovered carbon fibre by fibre alignment.

  8. Properties of hemp fibre polymer composites - An optimisation of fibre properties using novel defibration methods and fibre characterisation

    DEFF Research Database (Denmark)

    Thygesen, Anders

    2006-01-01

    Characterization of hemp fibres was carried out with fibres obtained with low handling damage and defibration damage to get an indication of how strong cellulose based fibres that can be produced from hemp. Comparison was made with hemp yarn producedunder traditional conditions where damage...... obtained by steam explosion of hemp fibres prior defibrated with pectin degrading enzymes. The S2 layer in the fibre wall of the hemp fibres consisted of1-4 cellulose rich and lignin poor concentric layers constructed of ca. 100 nm thick lamellae. The microfibril angle showed values in the range 0......-10° for the main part of the S2-layer and 70-90° for the S1-layer. The microfibrils that are mainly parallelwith the fibre axis explain the high fibre stiffness, which in defibrated hemp fibres reached 94 GPa. The defibrated hemp fibres had higher fibre stiffness (88-94 GPa) than hemp yarn (60 GPa), which...

  9. Microstructured Optical Fibres

    DEFF Research Database (Denmark)

    1999-01-01

    complete PBGs, which reflects light incident from air or vacuum. Such structures may be used as cladding structures in optical fibres, where light is confined and thereby guided in a hollow core region. In addition, the present invention relates to designs for ultra low-loss PBG waveguiding structures......The present invention relates to a new class of optical waveguides, in which waveguiding along one or more core regions is obtained through the application of the Photonic Bandgap (PBG) effect. The invention further relates to optimised two-dimensional lattice structures capable of providing...

  10. D fibre antenna for microcellular communications

    CERN Document Server

    Bhatti, A A

    2003-01-01

    Over the years, optical fibre sensors have been developed for many application areas. With the recent growth of microcellular communication systems this area has great economic potential. Therefore with this in mind one promising application for a new optical fibre sensor system is in the detection of Radio Frequency/Electric Fields (RF/EF). By constructing such a sensor from totally dielectric materials, it could be used as an antenna for receiving radio frequency transmissions without distorting or disturbing the field lines since there are no metallic components to reflect or transmit radio frequency energy. One of the key issues in the realisation of Radio-over-Fibre (RoF) architecture is the development of an effective means of generating and transmitting the radio subcarrier. The simplest method for the optical generation of radio signals, for transmission through an optical network is to directly modulate the light source with the received RF signal. Direct modulation of the laser can lead to a number ...

  11. Bundled capillary electrophoresis using microstructured fibres.

    Science.gov (United States)

    Rogers, Benjamin; Gibson, Graham T T; Oleschuk, Richard D

    2011-01-01

    Joule heating, arising from the electric current passing through the capillary, causes many undesired effects in CE that ultimately result in band broadening. The use of narrow-bore capillaries helps to solve this problem as smaller cross-sectional area results in decreased Joule heating and the rate of heat dissipation is increased by the larger surface-to-volume ratio. Issues arising from such small capillaries, such as poor detection sensitivity, low loading capacity and high flow-induced backpressure (complicating capillary loading) can be avoided by using a bundle of small capillaries operating simultaneously that share buffer reservoirs. Microstructured fibres, originally designed as waveguides in the telecommunication industry, are essentially a bundle of parallel ∼5 μm id channels that extend the length of a fibre having otherwise similar dimensions to conventional CE capillaries. This work presents the use of microstructured fibres for CZE, taking advantage of their relatively high surface-to-volume ratio and the small individual size of each channel to effect highly efficient separations, particularly for dye-labelled peptides.

  12. Design of DFB fibre lasers

    DEFF Research Database (Denmark)

    Lauridsen, Vibeke Claudia; Povlsen, Jørn Hedegaard; Varming, Poul

    1998-01-01

    A numerical model for erbium distributed feedback (DFB) fibre lasers is presented. The model is used to optimise the location of a discrete phase-shift to obtain maximum output power. For DFB fibre lasers of up to 10cm in length it is shown that the influence of Kerr nonlinearity with respect...

  13. Regulatory risk assessment approaches for synthetic mineral fibres.

    Science.gov (United States)

    Harrison, Paul; Holmes, Philip; Bevan, Ruth; Kamps, Klaus; Levy, Leonard; Greim, Helmut

    2015-10-01

    Exposure to synthetic mineral fibres (SMF) may occur in a number of workplace scenarios. To protect worker health, a number of different organisations worldwide have assessed the health risk of these materials and established workplace exposure limits. This paper outlines the basic principles of risk assessment and the scientific methods used to derive valid (justifiable) occupational exposure limits (OELs) and goes on to show how, for SMF, and particularly for refractory ceramic fibre (otherwise known as aluminosilicate wool, RCF/ASW), the methods used and the associated outcomes differ widely. It is argued that the resulting differences in established OELs prevent consistent and appropriate risk management of SMF worldwide, and that development of a transparent and harmonised approach to fibre risk assessment and limit-setting is required.

  14. Reticulation des fibres lignocellulosiques

    Science.gov (United States)

    Landrevy, Christel

    Pour faire face à la crise économique la conception de papier à valeur ajoutée est développée par les industries papetières. Le but de se projet est l'amélioration des techniques actuelles de réticulation des fibres lignocellulosiques de la pâte à papier visant à produire un papier plus résistant. En effet, lors des réactions de réticulation traditionnelles, de nombreuses liaisons intra-fibres se forment ce qui affecte négativement l'amélioration anticipée des propriétés physiques du papier ou du matériau produit. Pour éviter la formation de ces liaisons intra-fibres, un greffage sur les fibres de groupements ne pouvant pas réagir entre eux est nécessaire. La réticulation des fibres par une réaction de « click chemistry » appelée cycloaddition de Huisgen entre un azide et un alcyne vrai, catalysée par du cuivre (CuAAC) a été l'une des solutions trouvée pour remédier à ce problème. De plus, une adaptation de cette réaction en milieux aqueux pourrait favoriser son utilisation en milieu industriel. L'étude que nous désirons entreprendre lors de ce projet vise à optimiser la réaction de CuAAC et les réactions intermédiaires (propargylation, tosylation et azidation) sur la pâte kraft, en milieu aqueux. Pour cela, les réactions ont été adaptées en milieu aqueux sur la cellulose microcristalline afin de vérifier sa faisabilité, puis transférée à la pâte kraft et l'influence de différents paramètres comme le temps de réaction ou la quantité de réactifs utilisée a été étudiée. Dans un second temps, une étude des différentes propriétés conférées au papier par les réactions a été réalisée à partir d'une série de tests papetiers optiques et physiques. Mots Clés Click chemistry, Huisgen, CuAAC, propargylation, tosylation, azidation, cellulose, pâte kraft, milieu aqueux, papier.

  15. The environmental impact of fibre crops in industrial applications

    NARCIS (Netherlands)

    Dam, van J.E.G.; Bos, H.L.

    2004-01-01

    A short literature survey is presented on health and environmental issues in relation to the production and use of fibre crops. Next a short introduction to Life Cycle Analysis (LCA) is given and the various commonly applied methods for quantifying ecological impacts are discussed in short. The avai

  16. Random distributed feedback fibre lasers

    Science.gov (United States)

    Turitsyn, Sergei K.; Babin, Sergey A.; Churkin, Dmitry V.; Vatnik, Ilya D.; Nikulin, Maxim; Podivilov, Evgenii V.

    2014-09-01

    The concept of random lasers exploiting multiple scattering of photons in an amplifying disordered medium in order to generate coherent light without a traditional laser resonator has attracted a great deal of attention in recent years. This research area lies at the interface of the fundamental theory of disordered systems and laser science. The idea was originally proposed in the context of astrophysics in the 1960s by V.S. Letokhov, who studied scattering with “negative absorption” of the interstellar molecular clouds. Research on random lasers has since developed into a mature experimental and theoretical field. A simple design of such lasers would be promising for potential applications. However, in traditional random lasers the properties of the output radiation are typically characterized by complex features in the spatial, spectral and time domains, making them less attractive than standard laser systems in terms of practical applications. Recently, an interesting and novel type of one-dimensional random laser that operates in a conventional telecommunication fibre without any pre-designed resonator mirrors-random distributed feedback fibre laser-was demonstrated. The positive feedback required for laser generation in random fibre lasers is provided by the Rayleigh scattering from the inhomogeneities of the refractive index that are naturally present in silica glass. In the proposed laser concept, the randomly backscattered light is amplified through the Raman effect, providing distributed gain over distances up to 100 km. Although an effective reflection due to the Rayleigh scattering is extremely small (˜0.1%), the lasing threshold may be exceeded when a sufficiently large distributed Raman gain is provided. Such a random distributed feedback fibre laser has a number of interesting and attractive features. The fibre waveguide geometry provides transverse confinement, and effectively one-dimensional random distributed feedback leads to the generation

  17. Random distributed feedback fibre lasers

    Energy Technology Data Exchange (ETDEWEB)

    Turitsyn, Sergei K., E-mail: s.k.turitsyn@aston.ac.uk [Aston Institute of Photonic Technologies, Aston University, Birmingham B4 7ET (United Kingdom); Novosibirsk State University, 2 Pirogova str., 630090, Novosibirsk (Russian Federation); Babin, Sergey A. [Novosibirsk State University, 2 Pirogova str., 630090, Novosibirsk (Russian Federation); Institute of Automation and Electrometry SB RAS, 1 Ac. Koptug. ave., 630090, Novosibirsk (Russian Federation); Churkin, Dmitry V. [Aston Institute of Photonic Technologies, Aston University, Birmingham B4 7ET (United Kingdom); Novosibirsk State University, 2 Pirogova str., 630090, Novosibirsk (Russian Federation); Institute of Automation and Electrometry SB RAS, 1 Ac. Koptug. ave., 630090, Novosibirsk (Russian Federation); Vatnik, Ilya D.; Nikulin, Maxim [Institute of Automation and Electrometry SB RAS, 1 Ac. Koptug. ave., 630090, Novosibirsk (Russian Federation); Podivilov, Evgenii V. [Novosibirsk State University, 2 Pirogova str., 630090, Novosibirsk (Russian Federation); Institute of Automation and Electrometry SB RAS, 1 Ac. Koptug. ave., 630090, Novosibirsk (Russian Federation)

    2014-09-10

    The concept of random lasers exploiting multiple scattering of photons in an amplifying disordered medium in order to generate coherent light without a traditional laser resonator has attracted a great deal of attention in recent years. This research area lies at the interface of the fundamental theory of disordered systems and laser science. The idea was originally proposed in the context of astrophysics in the 1960s by V.S. Letokhov, who studied scattering with “negative absorption” of the interstellar molecular clouds. Research on random lasers has since developed into a mature experimental and theoretical field. A simple design of such lasers would be promising for potential applications. However, in traditional random lasers the properties of the output radiation are typically characterized by complex features in the spatial, spectral and time domains, making them less attractive than standard laser systems in terms of practical applications. Recently, an interesting and novel type of one-dimensional random laser that operates in a conventional telecommunication fibre without any pre-designed resonator mirrors–random distributed feedback fibre laser–was demonstrated. The positive feedback required for laser generation in random fibre lasers is provided by the Rayleigh scattering from the inhomogeneities of the refractive index that are naturally present in silica glass. In the proposed laser concept, the randomly backscattered light is amplified through the Raman effect, providing distributed gain over distances up to 100 km. Although an effective reflection due to the Rayleigh scattering is extremely small (∼0.1%), the lasing threshold may be exceeded when a sufficiently large distributed Raman gain is provided. Such a random distributed feedback fibre laser has a number of interesting and attractive features. The fibre waveguide geometry provides transverse confinement, and effectively one-dimensional random distributed feedback leads to the

  18. ORAL ISSUE OF THE JOURNAL "USPEKHI FIZICHESKIKH NAUK": Special scientific session of the Editorial Board of the journal "Uspekhi Fizicheskikh Nauk" honoring Vitalii Lazarevich Ginzburg on his 90th birthday (3 October 2006)

    Science.gov (United States)

    2007-04-01

    A Special scientific session of the Editorial Board of the journal Uspekhi Fizicheskikh Nauk (an oral issue of the journal UFN) was held in the Conference Hall of the P N Lebedev Physical Institute, Russian Academy of Sciences (Moscow), on 3 October 2006. Several topical physical problems from the list given by Vitalii Lazarevich Ginzburg in his Nobel Lecture (Ginzburg's list) were discussed [in the order of the problems appeared on Ginzburg's list (see p. 332)].

  19. Tapered optical fibres for sensing

    Science.gov (United States)

    Martan, Tomas; Kanka, Jiri; Kasik, Ivan; Matejec, Vlastimil

    2008-11-01

    Recently, optical fibre tapers have intensively been investigated for many applications e.g. in telecommunications, medicine and (bio-) chemical sensing. The paper deals with enhancement of evanescent-field sensitivity of the solid-core microstructured fibre with steering-wheel air-cladding. Enhancement of a performance of the microstructured fibre is based on reduction of fibre core diameter down to narrow filament by tapering thereby defined part of light power is guided by an evanescent wave traveling in axial cladding air holes. The original fibre structure with outer diameter of 125 µm was reduced 2×, 2.5×, 3.33×, and 4× for increasing relatively small intensity overlap of guided core mode at wavelength of 1.55 μm with axial air holes. The inner structures of tapered microstructured fibre with steering-wheel aircladding were numerically analyzed and mode intensity distributions were calculated using the FDTD technique. Analyzed fiber tapers were prepared by constructed fibre puller employing 'flame brush technique'.

  20. Wetting of flexible fibre arrays.

    Science.gov (United States)

    Duprat, C; Protière, S; Beebe, A Y; Stone, H A

    2012-02-23

    Fibrous media are functional and versatile materials, as demonstrated by their ubiquity both in natural systems such as feathers and adhesive pads and in engineered systems from nanotextured surfaces to textile products, where they offer benefits in filtration, insulation, wetting and colouring. The elasticity and high aspect ratios of the fibres allow deformation under capillary forces, which cause mechanical damage, matting self-assembly or colour changes, with many industrial and ecological consequences. Attempts to understand these systems have mostly focused on the wetting of rigid fibres or on elastocapillary effects in planar geometries and on a fibre brush withdrawn from an infinite bath. Here we consider the frequently encountered case of a liquid drop deposited on a flexible fibre array and show that flexibility, fibre geometry and drop volume are the crucial parameters that are necessary to understand the various observations referred to above. We identify the conditions required for a drop to remain compact with minimal spreading or to cause a pair of elastic fibres to coalesce. We find that there is a critical volume of liquid, and, hence, a critical drop size, above which this coalescence does not occur. We also identify a drop size that maximizes liquid capture. For both wetting and deformation of the substrates, we present rules that are deduced from the geometric and material properties of the fibres and the volume of the drop. These ideas are applicable to a wide range of fibrous materials, as we illustrate with examples for feathers, beetle tarsi, sprays and microfabricated systems.

  1. [Small fibre neuropathy: knowledge is power].

    NARCIS (Netherlands)

    Hoeijmakers, J.G.; Bakkers, M.; Blom, E.W.; Drenth, J.P.H.; Merkies, I.S.; Faber, C.G.

    2012-01-01

    Small fibre neuropathy is a neuropathy of the small non-myelinated C-fibres and myelinated Adelta-fibres. Clinically, an isolated small fibre neuropathy is distinguished by sensory and autonomic symptoms, with practically no abnormalities on neurological examination other than possible distorted pai

  2. Dispersion properties of photonic crystal fibres

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Broeng, Jes; Dridi, Kim;

    1998-01-01

    Approximate dispersion and bending properties of all-silica two-dimensional photonic crystal fibres are characterised by the combination of an effective-index model and classical analysis tools for optical fibres. We believe for the first time to have predicted the dispersion properties of photonic...... crystal fibres. The results strongly indicate that these fibres have potential applications as dispersion managing components...

  3. Properties of hemp fibre polymer composites - An optimisation of fibre properties using novel defibration methods and fibre characterisation

    OpenAIRE

    Thygesen, Anders

    2006-01-01

    Characterization of hemp fibres was carried out with fibres obtained with low handling damage and defibration damage to get an indication of how strong cellulose based fibres that can be produced from hemp. Comparison was made with hemp yarn producedunder traditional conditions where damage is unavoidable. The mild defibration was performed by degradation of the pectin and lignin rich middle lamellae around the fibres by cultivation of the mutated white rot fungus Phlebia radiata Cel 26. Fibr...

  4. Periodic Structures in Optical Fibres.

    Science.gov (United States)

    Hand, Duncan Paul

    1990-01-01

    Available from UMI in association with The British Library. The work presented in this thesis concerns techniques for the formation of periodic structures in optical fibres. Two different methods of producing such structures are studied in detail. The first of these involves a breakdown mechanism (known as the 'fibre fuse') that permanently damages the core glass in a periodic manner leaving it unable to guide light. The dynamics of this mechanism are studied, with a view to controlling it for the production of interactive grating structures. It is determined that, due to a sharp rise in fibre absorption with temperature, a thermal shock -wave, with a typical thermal gradient of several hundred degrees Kelvin per micron, forms and travels along the fibre, heating the core glass to such an extent that damage occurs. The periodicity of the resultant damage arises from thermal focusing and defocusing of light in the region of this shock-wave. The second method makes use of the photorefractivity observed in certain germanosilicate fibres on exposure to moderate intensity blue light of wavelength ~480nm or UV light ~240nm. A single-mode fibre transmission filter is demonstrated for the first time, produced by exposing a fibre Sagnac loop mirror to 488nm holographic fringes. Average index changes are shown to occur if such fibres are exposed to spatially uniform blue or UV light, indicating that grating formation is by a different mechanism to the local charge separation which occurs in photorefractive crystals. The various characteristics of these average index changes are measured and analysed, with the conclusion that they result from defect centre formation, driven by two photon absorption with blue light, or single photon absorption with UV light. Associated birefringence changes are also measured and are exploited in a hi-bi fibre to periodically perturb the birefringence axes, producing a narrow-line transmission filter.

  5. Resonance modes in optical fibres

    Institute of Scientific and Technical Information of China (English)

    余寿绵; 余恬

    2002-01-01

    The weakly nonlinear boundary value problem of wave propagation in an optical fibre (for the transverse electric mode, for example) is formulated and a modified linear solution is obtained. It is shown that a self-consistent theory of fibre optics should be weakly nonlinear. The mode of critical refraction that does not exist in the linear theory is obtained, showing that it is a mode consisting of resonance modes. It is shown that the signal carriers in a long fibre are of resonance modes, not normal modes. Some experimental data are given for comparison with the theoretical predictions, and the agreement seems satisfactory.

  6. Scientific Freedom and Responsibility

    Science.gov (United States)

    Cretsos, James M.

    1976-01-01

    Recommends that the American Society for Information Science become involved and cooperate with the American Association for the Advancement of Science in the issue of scientific freedom and responsibility. (Author/PF)

  7. Intrafusal muscle fibre types in frog spindles.

    Science.gov (United States)

    Diwan, F H; Ito, F

    1989-04-01

    Muscle spindles from bullfrog semitendinosus, iliofibularis and sartorius muscles were examined with light and electron microscopy. Four types of intrafusal muscle fibre were identified according to their diameter, central nucleation and reticular zone arrangement: a large nuclear bag fibre, a medium nuclear bag fibre, and two types of small nuclear chain fibres with and without a reticular zone, respectively. It is suggested that they are comparable to the nuclear bag1, bag2 and chain fibres in mammalian muscle spindles.

  8. Intrafusal muscle fibre types in frog spindles.

    OpenAIRE

    Diwan, F H; Ito, F

    1989-01-01

    Muscle spindles from bullfrog semitendinosus, iliofibularis and sartorius muscles were examined with light and electron microscopy. Four types of intrafusal muscle fibre were identified according to their diameter, central nucleation and reticular zone arrangement: a large nuclear bag fibre, a medium nuclear bag fibre, and two types of small nuclear chain fibres with and without a reticular zone, respectively. It is suggested that they are comparable to the nuclear bag1, bag2 and chain fibres...

  9. A Perspective on Knowing about Global Warming and a Critical Comment about Schools and Curriculum in Relation to Socio-Scientific Issues

    Science.gov (United States)

    Levinson, Ralph

    2012-01-01

    The focus of this response to Virginie Albe and Marie-Jose Gombert's (2011) article on a research study of students' school science conference on global warming is to develop some thoughts on covert assumptions which underpin any such conference. My comments refer to the politics behind the production of scientific knowledge of climate change and…

  10. A Perspective on Knowing about Global Warming and a Critical Comment about Schools and Curriculum in Relation to Socio-Scientific Issues

    Science.gov (United States)

    Levinson, Ralph

    2012-01-01

    The focus of this response to Virginie Albe and Marie-Jose Gombert's (2011) article on a research study of students' school science conference on global warming is to develop some thoughts on covert assumptions which underpin any such conference. My comments refer to the politics behind the production of scientific knowledge of climate change and…

  11. Accurate Sky Continuum Subtraction with Fibre-fed Spectrographs

    CERN Document Server

    Yang, Yanbin; Puech, Mathieu; Flores, Hector; Royer, Frederic; Disseau, Karen; Gonçalves, Thiago; Hammer, François; Cirasuolo, Michele; Evans, Chris; Causi, Gianluca Li; Maiolino, Roberto; Melo, Claudio

    2013-01-01

    Fibre-fed spectrographs now have throughputs equivalent to slit spectrographs. However, the sky subtraction accuracy that can be reached has often been pinpointed as one of the major issues associated with the use of fibres. Using technical time observations with FLAMES-GIRAFFE, two observing techniques, namely dual staring and cross beam-switching, were tested and the resulting sky subtraction accuracy reached in both cases was quantified. Results indicate that an accuracy of 0.6% on sky subtraction can be reached, provided that the cross beam-switching mode is used. This is very encouraging with regard to the detection of very faint sources with future fibre-fed spectrographs, such as VLT/MOONS or E-ELT/MOSAIC.

  12. Extreme Silica Optical Fibre Gratings

    Directory of Open Access Journals (Sweden)

    Kevin Cook

    2008-10-01

    Full Text Available A regenerated optical fibre Bragg grating that survives temperature cycling up to 1,295°C is demonstrated. A model based on seeded crystallisation or amorphisation is proposed.

  13. Current status of natural fibres

    CSIR Research Space (South Africa)

    Anandjiwala, RD

    2006-12-01

    Full Text Available , automotive, aerospace, marine, electronic, leisure and household uses. This paper will provide an overview of the current status of research and development. It will also deal with future drivers for the growth and competitiveness of natural fibres...

  14. Natural Fibre-Reinforced Biofoams

    Directory of Open Access Journals (Sweden)

    Anne Bergeret

    2011-01-01

    Full Text Available Starches and polylactic acids (PLAs represent the main biobased and biodegradable polymers with potential industrial availability in the next decades for “bio” foams applications. This paper investigates the improvement of their morphology and properties through processing and materials parameters. Starch foams were obtained by melt extrusion in which water is used as blowing agent. The incorporation of natural fibres (hemp, cellulose, cotton linter, sugarcane, coconut in the starch foam induced a density reduction up to 33%, a decrease in water absorption, and an increase in mechanical properties according to the fibre content and nature. PLA foams were obtained through single-screw extrusion using of a chemical blowing agent that decomposed at the PLA melting temperature. A void content of 48% for PLA and 25% for cellulose fibre-reinforced PLA foams and an improvement in mechanical properties were achieved. The influence of a fibre surface treatment was investigated for both foams.

  15. Modeling of photonic Crystal Fibres

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Broeng, Jes; Barkou, Stig Eigil

    1999-01-01

    Diferent theoretical models for analysis of photonic crystal fibres are reviewed and compaired. The methods span from simple scalar approaches to full-vectorial models using different mode-field decompositions. The specific advantages of the methods are evaluated.......Diferent theoretical models for analysis of photonic crystal fibres are reviewed and compaired. The methods span from simple scalar approaches to full-vectorial models using different mode-field decompositions. The specific advantages of the methods are evaluated....

  16. Connectorization of fibre Bragg grating sensors recorded in microstructured polymer optical fibre

    DEFF Research Database (Denmark)

    Abang, A.; Saez-Rodriguez, D.; Nielsen, Kristian

    2013-01-01

    We describe te production and characterization of FC/PC connectorised fibre Bragg grating sensors in polymer fibre. Sensors were recorded in few-moded and single mode microstructured fibre composed of poly (methyl methacrylate).......We describe te production and characterization of FC/PC connectorised fibre Bragg grating sensors in polymer fibre. Sensors were recorded in few-moded and single mode microstructured fibre composed of poly (methyl methacrylate)....

  17. Analysis of a Few Scientific Issues from Philosophical Exchange Views%从交换哲学观试看几个科学问题

    Institute of Scientific and Technical Information of China (English)

    张占高

    2012-01-01

    归纳与演绎的往复循环是人类认知的基本进程。根据科学原理可以归纳出交换自然观,从而对科学研究面临的一些重大问题进行演绎,做出假说。假说一:质能关系即交换关系。根据"引力质量"定义,物体运动就是对地球引力一定程度的摆脱,必然要表现为质量的减小和能量的增大,并且运动的速度越快,即对引力的摆脱越多,质量就越减小而能量就越增大,其质量与速度成反比,能量与速度成正比,表现为质量与能量的交换,据此,就可以推导出质能交换式,即E=F+(1-1/v)m0.v,从而将基础理论研究向前推进一步。假说二:宇宙形成于交换。对宇宙形成的"大爆炸"说,完全可以理解为大交换原理,因为爆炸不可能是单一物质的运动,应该是两种或两种以上物质的相互交换作用,其初始的瞬间表现为"大爆炸"的形式而已。假说三:火星上没有生命。根据交换原理和地球经验,液态的水既是生命体必需的物质,也是交换出生命物质必需的介质,而火星距太阳较地球远,其表温较低,即使上面有水,也只能以固态存在,处于非交换的封闭状态,根本不可能交换出生命物质来。%The alteration of induction and deduction has been the basic course of man's cognition.On the basis of scientific principles can be inducted the exchange view of nature,from which the deductions are made on significant issues that science faces to reach a hypothesis.Hypothesis one: mass-energy relation is the relation of exchange.Based on the definition of "gravitational mass",the motion of an object is to some extent the breaking away force from the gravity of the earth,manifesting the reduction of mass and increment of energy.The faster its speed,or the stronger the breaking away force,the smaller the mass,and more the energy.Its mass is in inverse proportion to its speed,while its energy is in proportion to its speed

  18. Forward progress of scientific inquiry into the early father-child relationship: introduction to the special issue on very young children and their fathers.

    Science.gov (United States)

    Bocknek, Erika L; Hossain, Ziarat; Roggman, Lori

    2014-01-01

    Research on fathering and the father-child relationship has made substantial progress in the most recent 15 years since the last special issue of the Infant Mental Health Journal on fathers and young children. This special issue on fathers and young children contains a series of papers exemplifying this progress, including advances in methodology-more direct assessment and more observational measures-in addition to the increasing dynamic complexity of the conceptual models used to study fathers, the diversity of fathers studied, and the growth of programs to support early father involvement. In assessing the current state of the field, special attention is given to contributions made by the papers contained in this special issue, and two critical areas for continued progress are addressed: (1) methodological and measurement development that specifically address fathers and fathering relationships and (2) cross-cultural and ecologically valid research examining the diversity of models of fathering.

  19. 科技期刊过刊的价值利用——以《护理学报》为例%Scientific journal back issue' s value in use: take Journal of Nursing as an example

    Institute of Scientific and Technical Information of China (English)

    江霞; 李亚洁; 方玉桂; 吴艳妮

    2011-01-01

    Methods of scientific journal back issue' s value in use are summarized. It includes Offering back issues to the libraries in the journal not sold areas, the outlying areas, or the grass -roots,and donating towards the paramedics, nursing schools and teaching hospitals. These methods could use the back issues efficiently,raise the journal' circulation and influence, enhance the paramedics' scientific research writing, broaden contributions and attract high quality contributions.%总结科技期刊过刊的价值利用方法.认为赠送过刊给期刊发行未覆盖的地区医院、边远地区及基层医院图书馆以及护理人员、护理院校及教学医院,可以有效开发利用过刊资源,提高期刊发行量,扩大影响力,提高护理人员的论文写作水平,拓宽稿源并吸引优秀稿件.

  20. Strength of Concrete Containing Basalt Fibre

    Directory of Open Access Journals (Sweden)

    Parvez Imraan Ansari

    2015-04-01

    Full Text Available This paper presents the comparative study of effect of basalt fibre on compressive and split tensile strength of M40 grade concrete. The basalt fibre was mixed in concrete by (0.5%, 1%, and 1.5% of its total weight of cement in concrete. Results indicated that the strength increases with increase of basalt fibre content up to 1.0% beyond that there is a reduction in strength on increasing basalt fibre. The results show that the concrete specimen with 1.0% of basalt fibre gives better performance when it compared with 0.5%and 1.5% basalt fibre mix in concrete specimens.

  1. Practical Hydrogen Loading of Air Silica Fibres

    DEFF Research Database (Denmark)

    Sørensen, Henrik Rokkjær; Jensen, Jesper Bevensee; Jensen, Jesper Bo Damm

    2005-01-01

    A method for hydrogen-loading air-silica optical fibres has been developed allowing out-diffusion times comparable to standard step-index fibres. Examples of the first grating written in Ge-doped air-silica fibres using a 266nm UV-laser are shown.......A method for hydrogen-loading air-silica optical fibres has been developed allowing out-diffusion times comparable to standard step-index fibres. Examples of the first grating written in Ge-doped air-silica fibres using a 266nm UV-laser are shown....

  2. Carbon nanotubes for ultrafast fibre lasers

    Directory of Open Access Journals (Sweden)

    Chernysheva Maria

    2017-01-01

    Full Text Available Carbon nanotubes (CNTs possess both remarkable optical properties and high potential for integration in various photonic devices. We overview, here, recent progress in CNT applications in fibre optics putting particular emphasis on fibre lasers. We discuss fabrication and characterisation of different CNTs, development of CNT-based saturable absorbers (CNT-SA, their integration and operation in fibre laser cavities putting emphasis on state-of-the-art fibre lasers, mode locked using CNT-SA. We discuss new design concepts of high-performance ultrafast operation fibre lasers covering ytterbium (Yb, bismuth (Bi, erbium (Er, thulium (Tm and holmium (Ho-doped fibre lasers.

  3. Carbon nanotubes for ultrafast fibre lasers

    Science.gov (United States)

    Chernysheva, Maria; Rozhin, Aleksey; Fedotov, Yuri; Mou, Chengbo; Arif, Raz; Kobtsev, Sergey M.; Dianov, Evgeny M.; Turitsyn, Sergei K.

    2017-01-01

    Carbon nanotubes (CNTs) possess both remarkable optical properties and high potential for integration in various photonic devices. We overview, here, recent progress in CNT applications in fibre optics putting particular emphasis on fibre lasers. We discuss fabrication and characterisation of different CNTs, development of CNT-based saturable absorbers (CNT-SA), their integration and operation in fibre laser cavities putting emphasis on state-of-the-art fibre lasers, mode locked using CNT-SA. We discuss new design concepts of high-performance ultrafast operation fibre lasers covering ytterbium (Yb), bismuth (Bi), erbium (Er), thulium (Tm) and holmium (Ho)-doped fibre lasers.

  4. Issues and Scientific Use of Sports Nutritional Supplements by Athletes%运动员应用营养品存在的问题与科学应用

    Institute of Scientific and Technical Information of China (English)

    伊木清

    2012-01-01

    The article briefly introduces the history of sports nutritional supplements their classification and functional evaluation in China, and focuses on discussing the issues and scientific use of sports nutritional supplements by athletes.%简述了运动营养品在中国的发展、运动营养品的分类及功效评价,重点阐述了运动营养品本身及运动员应用存在的问题与改进措施及如何科学应用运动营养品。

  5. Fibre concentrations and size distributions of airborne fibres in several European man-made mineral fibre plants.

    Science.gov (United States)

    Dodgson, J; Ottery, J; Cherrie, J W; Harrison, G E

    1980-01-01

    Although the nominal diameters of fibres produced in the glass and rock wool industries are usually 6-15 micrometers, these products contain a small proportion of respirable fibres (less than 3 micrometers diameter). Particular significance has been attached to the biological risk arising from the long (greater than 10 micrometers), fine (less than 1 micrometers) fibres. Therefore, the medical research sponsored by the Joint European Medical Research Board into the effects of man-made fibres on health has included detailed environmental studies on both the exposure levels to respirable fibres and the fibre size distributions at the European plants selected for epidemiological work. This paper summarizes the results obtained so far. The size distributions (length and diameter) of the airborne man-made mineral fibres are compared with similar data previously reported for airborne asbestos fibres.

  6. Thermal analysis of bicomponent fibres

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, J.I. [Room I-320-D, ETS Ingenieros Industriales, Universidad de Malaga, Plaza El Ejido, s/n, 29013-Malaga (Spain)

    2007-02-15

    A one-dimensional model of amorphous bicomponent spun fibres derived from the use of perturbation methods based on the slenderness ratio is presented. The model accounts for gravitational, surface tension, axial heat conduction, viscous dissipation and the nonlinear dependence of the dynamic viscosity law on temperature, but does not consider latent heat effects and the radial gradients of temperature and assumes Newtonian rheology. Studies on the effects of the thermal parameters on the compound fibre's geometry and solidification have been performed, and show that the activation energy of the dynamic viscosity laws have a paramount effect on the fibre's cooling, shape, and axial stresses on the core and sheath. In particular, it is shown that, when the activation energy of the viscosity law for the core is higher than that for the sheath, the axial stresses on the core are monotonic functions of the distance along the fibre and higher than those on the sheath, whereas those in the latter may exhibit a nonmonotonic behavior as functions of the thermal conductivity, heat losses and thermal inertia. Despite its limitations, the model presented here represents an improvement over available one-dimensional models for non-isothermal compound or bicomponent fibres. (author)

  7. Scientific publication

    Directory of Open Access Journals (Sweden)

    Getulio Teixeira Batista

    2007-06-01

    Full Text Available The necessary work for developing a scientific publication is sometimes underestimated and requires the effective participation of many players to obtain a result in good standard. Initially it depends upon the determination of the authors that decide to write the scientific article. Scientific writing is a very challenging and time consuming task, but at the same time essential for any scientist. A published scientific article is unquestionably one of the main indicators of scientific production, especially if published in a qualified scientific journal with highly qualified editorial committee and strict peer review procedure. By looking at evaluation criteria for scientific production of the several Thematic Scientific Committees of the Brazilian Council for Scientific and Technological Development (CNPq it becomes clear publications in scientific journals that has certified quality is the most important item in the evaluation of a scientist production.

  8. Every silver lining has a cloud: the scientific and animal welfare issues surrounding a new approach to the production of transgenic animals.

    Science.gov (United States)

    Combes, Robert D; Balls, Michael

    2014-05-01

    The scientific basis and advantages of using recently developed CRISPR/Cas-9 technology for transgenesis have been assessed with respect to other production methods, laboratory animal welfare, and the scientific relevance of transgenic models of human diseases in general. As the new technology is straightforward, causes targeted DNA double strand breaks and can result in homozygous changes in a single step, it is more accurate and more efficient than other production methods and speeds up transgenesis. CRISPR/Cas-9 also obviates the use of embryonic stem cells, and is being used to generate transgenic non-human primates (NHPs). While the use of this method reduces the level of animal wastage resulting from the production of each new strain, any long-term contribution to reduction will be offset by the overall increase in the numbers of transgenic animals likely to result from its widespread usage. Likewise, the contribution to refinement of using a more-precise technique, thereby minimising the occurrence of unwanted genetic effects, will be countered by a probable substantial increase in the production of transgenic strains of increasingly sentient species. For ethical and welfare reasons, we believe that the generation of transgenic NHPs should be allowed only in extremely exceptional circumstances. In addition, we present information, which, on both welfare and scientific grounds, leads us to question the current policy of generating ever-more new transgenic models in light of the general failure of many of them, after over two decades of ubiquitous use, to result in significant advances in the understanding and treatment of many key human diseases. Because this unsatisfactory situation is likely to be due to inherent, as well as possibly avoidable, limitations in the transgenic approach to studying disease, which are briefly reviewed, it is concluded that a thorough reappraisal of the rationale for using genetically-altered animals in fundamental research and

  9. Biopersistence of man-made vitreous fibres.

    Science.gov (United States)

    Muhle, H; Bellmann, B

    1995-10-01

    Methods for the determination of biodurability of man-made vitreous fibres are reviewed. For mineral wools the first step was the preparation of respirable fibre fractions. Fibres were administered to rats by inhalation or by intratracheal instillation. After serial sacrifice their lungs were digested by low-temperature ashing or by hypochlorite. The total number of fibres per lung and the distributions of length and diameter were analysed by electron microscopy. This resulted in a bivariate distribution of fibres at the various sacrifice dates. If the logarithm of the number of fibres decreased approximately linearly with time after exposure then the elimination kinetics of fibres can be characterized by a half-time. The half-times were compared between various experiments with rats exposed to mineral wool samples. In summary good agreement was found for the elimination of fibres after long-term inhalation and intratracheal instillation whereas shorter half-times were found after short-term inhalation.

  10. Underwater Acoustic Sensing with Optical Fibres

    Directory of Open Access Journals (Sweden)

    V. V. Rampal

    1982-01-01

    Full Text Available The use of optical fibres for the detection of acoustic pressure underwater has been discussed with particular reference to the recent literature on the development of fibre optic hydrophones.

  11. A Contemplation on Scientific Ethics Issues of Medical Postgraduates%医学研究生科研伦理问题审思

    Institute of Scientific and Technical Information of China (English)

    曹强; 李情

    2015-01-01

    Scientific research is a strong driving force to accelerate the development of biomedical technology .However ,a series of ethical problems in scientific research have aroused wide social concerns .Through discussing the basic ethical code of research ethics of medical postgraduates , this paper revealed the major problems in data collection , data sharing , research integrity , intellectual property and honor distribution of human subject research and animal experiments . Furthermore ,it analyzed the reasons from the perspectives of students ,teachers ,education evaluation mechanism and social environment ,as well as the approach to promote the research ethics education of medical postgraduates .%科学研究是推动生物医学技术不断发展的强大动力,而研究过程中产生的一系列科研伦理规范问题逐渐引起社会的广泛关注。通过探讨医学研究生科研伦理的基本规范,揭示了目前医学研究生在科研伦理规范,如实验数据的采集处理以及共享、人体试验研究、动物实验研究、科研诚信、知识产权等方面存在的主要问题,并从学生、教师、教育评价机制、社会环境等方面对问题产生的原因进行分析,进一步思考如何加强医学研究生科研伦理规范教育。

  12. Hollow Core Photonic Crystal Fibre Comprising a Fibre Grating in the Cladding and its Applications

    DEFF Research Database (Denmark)

    2010-01-01

    An optical fibre is provided having a fibre cladding around a longitudinally extending optical propagation core. The cladding has a reflection region of a varying refractive index in the longitudinal direction.......An optical fibre is provided having a fibre cladding around a longitudinally extending optical propagation core. The cladding has a reflection region of a varying refractive index in the longitudinal direction....

  13. Exposure assessment for airborne man-made mineral fibres: the role of fibre dimensions.

    Science.gov (United States)

    Rosenthal, F S

    1993-08-01

    Environmental exposures to man-made mineral fibres (MMMF) typically contain fibres which are polydisperse with respect to fibre dimensions. Fibre dimensions may influence their biological action through effects on: the efficiency of transport to target tissues; the residence time in target tissues; and the biological activity of fibres in contact with target cells. This variability of biological activity vs fibre dimensions should be accounted for when assessing exposure for epidemiological studies of the risk of cancer in subjects exposed to MMMF. In order to provide insight into the influence of fibre dimensions on the potential carcinogenicity of MMMF, this paper reviews literature concerning the sites of lung tumours, regional fibre deposition, biological effects of fibres in in vivo and in vitro systems, dissolution rates of fibres and rates of physiological clearance of inhaled particles. Tumorigenicity of fibres in contact with target tissue appears to be primarily a function of fibre length, whereas both fibre diameter and fibre length may affect the penetration of fibres through the respiratory tract as well as their residence time in target tissues. A methodology is presented to use this information to compute estimates of biologically effective exposure from the joint distribution of fibre lengths and diameters found in an environmental exposure.

  14. LHCb Upgrade: Scintillating Fibre Tracker

    Science.gov (United States)

    Tobin, Mark

    2016-07-01

    The LHCb detector will be upgraded during the Long Shutdown 2 (LS2) of the LHC in order to cope with higher instantaneous luminosities and to read out the data at 40 MHz using a trigger-less read-out system. All front-end electronics will be replaced and several sub-detectors must be redesigned to cope with higher occupancy. The current tracking detectors downstream of the LHCb dipole magnet will be replaced by the Scintillating Fibre (SciFi) Tracker. The SciFi Tracker will use scintillating fibres read out by Silicon Photomultipliers (SiPMs). State-of-the-art multi-channel SiPM arrays are being developed to read out the fibres and a custom ASIC will be used to digitise the signals from the SiPMs. The evolution of the design since the Technical Design Report in 2014 and the latest R & D results are presented.

  15. Fibre Optics In Coal Mining

    Science.gov (United States)

    Cooper, Paul

    1984-08-01

    Coal mines have a number of unique problems which affect the use of fibre optic technology. These include a potentially explosive atmosphere due to the evolution of methane from coal, and a dirty environment with no cleaning facilities readily available. Equipment being developed by MRDE to allow the exploitation of optical fibres underground includes: A hybrid electrical/fibre optic connector for the flexible power trailing cable of the coal-face shearer; An Intrinsically Safe (IS) pulsed laser transmitter using Frequency Shift Key (FSK) data modulation; An IS Avalanche Photo Diode Receiver suitable for pulsed & continuous wave optical signals; A mine shaft and roadway cable/ connector system incorporating low loss butt-splices and preterminated demountable connectors.

  16. LHCb Upgrade: Scintillating Fibre Tracker

    Energy Technology Data Exchange (ETDEWEB)

    Tobin, Mark, E-mail: Mark.Tobin@epfl.ch

    2016-07-11

    The LHCb detector will be upgraded during the Long Shutdown 2 (LS2) of the LHC in order to cope with higher instantaneous luminosities and to read out the data at 40 MHz using a trigger-less read-out system. All front-end electronics will be replaced and several sub-detectors must be redesigned to cope with higher occupancy. The current tracking detectors downstream of the LHCb dipole magnet will be replaced by the Scintillating Fibre (SciFi) Tracker. The SciFi Tracker will use scintillating fibres read out by Silicon Photomultipliers (SiPMs). State-of-the-art multi-channel SiPM arrays are being developed to read out the fibres and a custom ASIC will be used to digitise the signals from the SiPMs. The evolution of the design since the Technical Design Report in 2014 and the latest R & D results are presented.

  17. Wavelength Filters in Fibre Optics

    CERN Document Server

    Venghaus, Herbert

    2006-01-01

    Wavelength filters constitute an essential element of fibre-optic networks. This book gives a comprehensive account of the principles and applications of such filters, including their technological realisation. After an introductory chapter on wavelength division multiplexing in current and future fibre optic networks follows a detailed treatment of the phase characteristics of wavelength filters, a factor frequently neglected but of significant importance at high bit rates. Subsequent chapters cover three-dimensional reflection of gratings, arrayed waveguide gratings, fibre Bragg gratings, Fabry-Perot filters, dielectric multilayer filters, ring filters, and interleavers. The book explains the relevant performance parameters, the particular advantages and shortcomings of the various concepts and components, and the preferred applications. It also includes in-depth information on the characteristics of both commercially available devices and those still at the R&D stage. All chapters are authored by inter...

  18. Implicit normativity in scientific advice

    DEFF Research Database (Denmark)

    Folker, Anna Paldam; Andersen, Hanne; Sandøe, Peter

    2008-01-01

    This paper focuses on implicit normative considerations underlying scientific advice-those normative questions, decisions, or issues that scientific advisers and the general public are not fully aware of but that nevertheless have implications for the character of the advice given. Using...... of these issues among scientific advisers and a wider public....... nutritional science as an example, we identify three such implicit normative issues. The first concerns the aim of scientific advice: whether it is about avoiding harm or promoting good. The second concerns the intended beneficiaries of the advice: whether advice should be framed to benefit the society...

  19. Implicit normativity in scientific advice

    DEFF Research Database (Denmark)

    Folker, Anna Paldam; Andersen, Hanne; Sandøe, Peter

    2008-01-01

    This paper focuses on implicit normative considerations underlying scientific advice-those normative questions, decisions, or issues that scientific advisers and the general public are not fully aware of but that nevertheless have implications for the character of the advice given. Using nutritio......This paper focuses on implicit normative considerations underlying scientific advice-those normative questions, decisions, or issues that scientific advisers and the general public are not fully aware of but that nevertheless have implications for the character of the advice given. Using...... nutritional science as an example, we identify three such implicit normative issues. The first concerns the aim of scientific advice: whether it is about avoiding harm or promoting good. The second concerns the intended beneficiaries of the advice: whether advice should be framed to benefit the society...... of these issues among scientific advisers and a wider public....

  20. Ductility Performance of Hybrid Fibre Reinforced Concrete

    OpenAIRE

    S. Eswari; P.N. Raghunath; Suguna, K

    2008-01-01

    This study presents a study on the ductility performance of hybrid fibre reinforced concrete. The influence of fibre content on the ductility performance of hybrid fibre reinforced concrete specimens having different fibre volume fractions was investigated. The parameters of investigation included modulus of rupture, ultimate load, service load, ultimate and service load deflection, crack width, energy ductility and deflection ductility. A total of 27 specimens, 100×100×500 mm, were tested to...

  1. Photonic crystal fibres and effective index approaches

    DEFF Research Database (Denmark)

    Riishede, Jesper; Libori, Stig E. Barkou; Bjarklev, Anders Overgaard

    2001-01-01

    Photonic crystal fibres are investigated with an effective index approach. The effective index of both core and cladding is found to be wavelength dependent. Accurate modelling must respect the rich topology of these fibres.......Photonic crystal fibres are investigated with an effective index approach. The effective index of both core and cladding is found to be wavelength dependent. Accurate modelling must respect the rich topology of these fibres....

  2. Photonic-crystal fibre: Mapping the structure

    DEFF Research Database (Denmark)

    Markos, Christos

    2015-01-01

    The demonstration of real-time and non-destructive Doppler-assisted tomography of the internal structure of photonic-crystal fibres could aid the fabrication of high-quality fibres with enhanced performance.......The demonstration of real-time and non-destructive Doppler-assisted tomography of the internal structure of photonic-crystal fibres could aid the fabrication of high-quality fibres with enhanced performance....

  3. Local fibred right adjoints are polynomial

    DEFF Research Database (Denmark)

    Kock, Anders; Kock, Joachim

    2013-01-01

    For any locally cartesian closed category E, we prove that a local fibred right adjoint between slices of E is given by a polynomial. The slices in question are taken in a well known fibred sense......For any locally cartesian closed category E, we prove that a local fibred right adjoint between slices of E is given by a polynomial. The slices in question are taken in a well known fibred sense...

  4. Optical Fibre Based Frequency Shifters Project

    Science.gov (United States)

    1991-01-28

    A fibre optic frequency shifter can be used to replace the Bragg cell acousto-optic modulator, currently used to generate low frequency optical...carriers, in fibre optic communications and sensor systems. This new form of frequency shifter, being an all fibre device, in which the propagating optical...large number of workers in recent years, (for example references [2-81 and those contained therein). The main elements of a fibre - optic frequency

  5. Optimal Extraction of Fibre Optic Spectroscopy

    CERN Document Server

    Sharp, R

    2009-01-01

    We report an optimal extraction methodology, for the reduction of multi-object fibre spectroscopy data, operating in the regime of tightly packed (and hence significantly overlapping) fibre profiles. The routine minimises crosstalk between adjacent fibres and statistically weights the extraction to reduce noise. As an example of the process we use simulations of the numerous modes of operation of the AAOmega fibre spectrograph and observational data from the SPIRAL Integral Field Unit at the Anglo-Australian Telescope.

  6. Fibre Optic Communication Key Devices

    CERN Document Server

    Grote, Norbert

    2012-01-01

    The book gives an in-depth description of the key devices of current and next generation fibre optic communication networks. In particular, the book covers devices such as semiconductor lasers, optical amplifiers, modulators, wavelength filters, and detectors but the relevant properties of optical fibres as well. The presentations include the physical principles underlying the various devices, the technologies used for the realization of the different devices, typical performance characteristics and limitations, and development trends towards more advanced components are also illustrated. Thus the scope of the book spans relevant principles, state-of-the-art implementations, the status of current research and expected future components.

  7. Portable smartphone optical fibre spectrometer

    Science.gov (United States)

    Hossain, Md. Arafat; Canning, John; Cook, Kevin; Jamalipour, Abbas

    2015-09-01

    A low cost, optical fibre based spectrometer has been developed on a smartphone platform for field-portable spectral analysis. Light of visible wavelength is collected using a multimode optical fibre and diffracted by a low cost nanoimprinted diffraction grating. A measurement range over 300 nm span (λ = 400 to 700 nm) is obtained using the smartphone CMOS chip. The spectral resolution is Δλ ~ 0.42 nm/screen pixel. A customized Android application processed the spectra on the same platform and shares with other devices. The results compare well with commercially available spectrometer.

  8. Experimental and theoretical assessment of flexural properties of hybrid natural fibre composites

    DEFF Research Database (Denmark)

    Raghavalu Thirumalai, Durai Prabhakaran; Toftegaard, Helmuth Langmaack; Markussen, Christen Malte

    2014-01-01

    The concept of hybridization of natural fibre composites with synthetic fibres is attracting increasing scientific attention. The present study addresses the flexural properties of hybrid flax/glass/epoxy composites to demonstrate the potential benefits of hybridization. The study covers both...... experimental and theoretical assessments. Composite laminates with different hybrid fibre mixing ratios and different layer configurations were manufactured, and their volumetric composition and flexural properties were measured. The relationship between volume fractions in the composites is shown to be well...... predicted as a function of the hybrid fibre mixing ratio. The flexural modulus of the composites is theoretically assessed by using micromechanical models and laminate theory. The model predictions are compared with the experimentally determined flexural properties. Both approaches show that the flexural...

  9. Friction and wear of human hair fibres

    Science.gov (United States)

    Bowen, James; Johnson, Simon A.; Avery, Andrew R.; Adams, Michael J.

    2016-06-01

    An experimental study of the tribological properties of hair fibres is reported, and the effect of surface treatment on the evolution of friction and wear during sliding. Specifically, orthogonally crossed fibre/fibre contacts under a compressive normal load over a series of 10 000 cycle studies are investigated. Reciprocating sliding at a velocity of 0.4 mm s-1, over a track length of 0.8 mm, was performed at 18 °C and 40%-50% relative humidity. Hair fibres retaining their natural sebum were studied, as well as those stripped of their sebum via hexane cleaning, and hair fibres conditioned using a commercially available product. Surface topography modifications resulting from wear were imaged using scanning electron microscopy and quantified using white light interferometry. Hair fibres that presented sebum or conditioned product at the fibre/fibre junction exhibited initial coefficients of friction at least 25% lower than those that were cleaned with hexane. Coefficients of friction were observed to depend on the directionality of sliding for hexane cleaned hair fibres after sufficient wear cycles that cuticle lifting was present, typically on the order 1000 cycles. Cuticle flattening was observed for fibre/fibre junctions exposed to 10 mN compressive normal loads, whereas loads of 100 mN introduced substantial cuticle wear and fibre damage.

  10. Mohair, cashmere and other animal hair fibres

    CSIR Research Space (South Africa)

    Hunter, L

    2012-11-01

    Full Text Available animal hair fibres L Hunter, CSIR and Nelson Mandela Metropolitan University (NMMU), South Africa Although luxury animal fibres, excluding silk, represent far less than 0.1% of global fibre production, they play a very significant role in the luxury...

  11. Issues in the Studies on Scientific Thought of Xue Feng-zuo%薛凤祚科学思想研究的若干问题

    Institute of Scientific and Technical Information of China (English)

    马来平

    2012-01-01

    关于《历学会通》对哥白尼日心体系的修改问题,科学史工作者提供的证据颇有说服力,应予以认真对待,但尚有探讨余地;明末清初正是中国传统天文历法、数学与占验开始萌发分离动向的时期,薛凤祚是这一潮流的见证人和主要参与者。其占验思想是其科学思想的有机组成部分,应给予宽容而客观的分析和评价;薛凤祚的科学观是其科学思想的核心,研究它须以近代科学观为参照系,如此,方能正确判断其科学观的性质,厘清其中弥足珍贵的近代因素。%Concerning the amendation of Copernicus's Heliocentric theory in Li Xue Hui Tong,historians of science have provided convincing evidences,which should be taken seriously and needs further investigation.Xue Feng-zuo was the witness and the main participant in the trend of Chinese traditional astronomy,calendar and mathematics dissociating from divination during the period of late Ming Dynasty and early Qing Dynasty.His thought on divination is an integral part of his scientific thought system,which should be given to tolerant and objective analysis and evaluation.Xue Feng-zuo's view of science is the core of his scientific thoughts,on which researches need to be based on the modern view of science to determine the nature of his view of science and clarify the precious modern factors from it.

  12. Occupational ceramic fibres dermatitis in Poland.

    Science.gov (United States)

    Kieć-Swierczyńska, M; Wojtczak, J

    2000-07-01

    Recently, the use of asbestos has been considerably limited in Poland, with the simultaneous increase in the manufacture, processing and application of man-made mineral fibres, which includes ceramic fibres. The aims of this study were (1) to assess the type and frequency of dermal changes caused by the irritant activity of ceramic fibres among workers at the plants that manufacture packing and insulation products; and (2) to compare the irritant activity of Polish-made L-2 and L-3 ceramic fibres with that of the Thermowool ceramic fibres made in England. Workers (n = 226) who were exposed to ceramic fibres underwent dermatological examination. Patch tests with the standard allergen set, together with samples of the fibres L-2, L-3, and Thermowool fibres, were applied to all the workers. It has been shown that the Polish-made L-2 and L-3 fibres differed from Thermowool fibres in that the L-2 and L-3 fibres contained zirconium and were coarser. The proportion of filaments with diameters above 3 microns was 11.1% in the L-3 fibre and 6.3% in the L-2 fibre samples. The Thermowool fibre did not contain filaments thicker than 3 microns. Evident dermal changes, resulting from strong irritant activity of the fibres, were detected in 109 (48.2%) of the workers examined. Irritant contact dermatitis acuta (maculae, sometimes papulae and small crusts on the upper extremities, trunk, and lower extremities), disappearing after 2-3 days, was found in 50 (22.1%) workers. Irritant contact dermatitis chronica (diffuse permanent erythema with numerous telangiectasiae on the lateral portions of the face and neck, on the trunk, behind the auricles) was detected in 40 (17.7%) workers. The remaining 19 (8.4%) workers had both types of dermal change. All examined workers complained of very strong itching. The results of the patch tests confirmed the irritant activity of the ceramic fibres. Erythema without oedema, persisting for up to 96 h, appeared at the places where the fibres had

  13. Ethical and Scientific Issues Surrounding Solid Organ Transplantation in Hiv-Positive Patients: Absence of Evidence Is Not Evidence of Absence

    Directory of Open Access Journals (Sweden)

    Timothy Christie

    2006-01-01

    Full Text Available End-stage liver disease is emerging as a leading cause of death among HIV-positive patients. Historically, an HIV diagnosis was a contraindication for a liver transplant; however, because of the efficacy of highly active antiretroviral therapy (HAART, HIV-positive patients have one-year, two-year, and three-year post-transplantation survival rates similar to that of HIV-negative patients. Based on this evidence, HIV-positive patients are now considered eligible for transplantation. However, newly emerging guidelines include the stipulation that HIV-positive patients must be on HAART to be placed on a waiting list for transplantation. The purpose of the present paper is to evaluate the scientific and ethical probity of requiring HIV-positive patients to be on HAART as a condition for being on a liver transplant waiting list. It is argued that the emphasis should be placed on the probability of post-transplantation HAART tolerance, and that concerns about pretransplantation HAART tolerance are of secondary importance.

  14. Scientific research on human subjects and ethics procedures at the Istituto Superiore di Sanità: a survey of the articles issued in 2001.

    Science.gov (United States)

    Rosmini, Francesco; Ferrigno, Luigina; D'Angelo, Franca; Poltronieri, Elisabetta

    2006-01-01

    Principles promoting the protection of subjects involved in biomedical research are interpreted differently within the scientific community. The purpose of this paper is to describe the attitudes of researchers working at the Istituto Superiore di Sanità (ISS) regarding the ethical implications of studies involving human beings, with particular emphasis on aspects concerning informed consent (IC) and ethics committee (EC) review. In 2001, ISS researchers published a total of 733 articles, 93 (12.7%) of which were studies involving human beings. Nearly 2/3 (60/93) were epidemiological, while the remaining 35.5% were based on laboratory data. Half (47/93) reported physical or psychological interventions or treatments on study subjects. 40.9% of articles mentioned that informed consent had been obtained and only 12.9% that approval had been given by an ethics committee. The low proportion of articles on which a protocol had been submitted the EC was due in part to the type of studies, but also to the absence of an institutional EC prior to 2001. Ethical procedures were more present in laboratory than in epidemiologic studies (IC: 69.7% vs 25.0%, p ethical awareness on the part of epidemiologists. Further efforts are needed to develop and enforce clear institutional policies regarding ethical procedures.

  15. Introducing Issues of the Local Science and Technology Knowledge into Public Scientific Literacy Survey%公众科学素养调查引入地方性科技知识问题案例研究

    Institute of Scientific and Technical Information of China (English)

    张秀珍; 任玉凤

    2011-01-01

    在文化人类学中,吉尔兹提出地方性知识概念,它强调了在特定环境中形成的具有文化特质的知识。在对"科学素养"概念理解多元化的背景下,公众科学素养调查引入地方性知识问题日益成为关注的焦点。本文在探讨科学素养调查引入地方性科技知识合理性问题的基础上,选取了兼具民族性和边缘性的内蒙古地区的公众,进行了国家标准问卷和具有内蒙古特色的地方性科技知识问卷的双重调查,并对调查结果进行了对比分析,以此对讨论的科学素养衡量标准多元化提供一个案例支持。%In cultural anthropology,Clifford Geertz proposes the concept of local knowledge,which emphasizes the kno-wledge of cultural traits form in a particular environment.In the"scientific literacy"concept to understand diversified background,introducing issues of the local knowledge into public scientific literacy survey increasingly becomes the focus of attention.This paper discusses the rationality of local knowledge into scientific literacy survey,and selects the public with local characteristics in the Inner Mongolia,making surveys using national suurvey questionnaire and local knowledge questionnaire respectively and analysis of the survey results,which provides support for diversified measurement for sci-entific literacy.

  16. Not Just a "Fleck" on the Epistemic Landscape: A Reappraisal of Ludwik Fleck's Views of the Nature of Scientific Progress and Change in Relation to Contemporary Educational and Social Issues

    Science.gov (United States)

    Carifio, James; Perla, Rocco J.

    2013-12-01

    In contrast to Thomas Kuhn, the work of Ludwik Fleck, a Polish-born physician, microbiologist, and epistemologist, is conspicuously absent from the science education literature. His originally obscure monograph first published in German in 1935, Genesis and Development of a Scientific Fact, anticipates a number of views explicated by contemporary philosophers of science, cognitive psychologists, and learning theorists, and Fleck's main thesis is, is many respects, strikingly similar to the oft-cited thesis developed later by Kuhn in The Structure of Scientific Revolutions. Fleck's work is perhaps the best example of the social influence on scientific commitment and thinking and is one of the first works to suggest different scales or varieties of change in science. At the same time as Fleck's work gains recognition, momentum, and force in philosophical circles, some educators are calling for a critical appraisal of Kuhn's impact on science education. This climate provides an ideal opportunity to assess (or perhaps in some cases reassess) the value of Fleck's work in a science education context. The primary aim of this article, therefore, is to introduce educators in general, and science educators in particular, to the main ideas developed by Fleck in his Genesis and Development of a Scientific Fact. Throughout this article, Fleck's ideas are compared and contrasted to those of Thomas Kuhn—arguably one of the most popular referents in nature of science studies over the past decade. As will be discussed, many of the ideas developed by Fleck anticipate central issues and perspectives in philosophy, epistemology, sociology, education, and cognitive psychology.

  17. A PHOTONIC BAND GAP FIBRE

    DEFF Research Database (Denmark)

    1999-01-01

    An optical fibre having a periodicidal cladding structure provididing a photonic band gap structure with superior qualities. The periodical structure being one wherein high index areas are defined and wherein these are separated using a number of methods. One such method is the introduction...

  18. Cool application for Optical Fibres

    CERN Multimedia

    2001-01-01

    In a new first for CERN, optical fibres have been put on test to measure very low temperatures. If these tests prove successful, this new technology could lead to important cost-saving changes in the way the temperatures of superconducting magnets are measured. There was excitement in the air last March when the team led by Walter Scandale and Luc Thévenaz tested very low temperature measurement using optical fibres. This spring in CERN's Cryogenics lab an idea was put to the test as a new kind of low-temperature thermometry using optical fibres was tested down to 2 Kelvin (around 300 degrees below room temperature), and the first results are looking good. Optical fibres are well known for their ability to carry large amounts of data around the world, but it is less well known that they can be used for measuring temperatures. The intuition that they might be able to measure very low temperatures - such as those of the LHC magnets - came to the attention of CERN's Walter Scandale at the Optical Fi...

  19. Compressibility of hemp bast fibres

    NARCIS (Netherlands)

    Westenbroek, A.P.H.; Roekel, van G.J.; Jong, de E.; Weickert, G.; Westerterp, R.K.

    1999-01-01

    A force-based characterization of the extrusion pulping process is necessary to be able to predict the effects of extrusion on fibres. To determine which forces are beneficial and which only cause energy consumption, the nature and the origin of the forces have to be known. This paper discusses the

  20. Threshold temperature optical fibre sensors

    Science.gov (United States)

    Stasiewicz, K. A.; Musial, J. E.

    2016-12-01

    This paper presents a new approach to manufacture a threshold temperature sensor based on a biconical optical fibre taper. The presented sensor employs the influence of variable state of concentration of some isotropic materials like wax or paraffin. Application of the above- mentioned materials is an attempt to prove that there is a possibility to obtain a low-cost, repeatable and smart sensor working as an in-line element. Optical fibre taper was obtained from a standard single mode fibre (SMF28®) by using a low pressure gas burner technique. The diameter of the manufactured tapers was 6.0 ± 0.5 μm with the length of elongation equal to 30.50 ± 0.16 mm. The applied technology allowed to produce tapers with the losses of 0.183 ± 0.015 dB. Application of materials with different temperature transition points made it possible to obtain the threshold work at the temperatures connected directly with their conversion temperature. External materials at the temperatures above their melting points do not influence the propagation losses. For each of them two types of the protection area and position of the optical fibre taper were applied.

  1. Nonlinear microstructured polymer optical fibres

    DEFF Research Database (Denmark)

    Frosz, Michael Henoch

    is potentially the case for microstructured polymer optical fibres (mPOFs). Another advantage is that polymer materials have a higher biocompatibility than silica, meaning that it is easier to bond certain types of biosensor materials to a polymer surface than to silica. As with silica PCFs, it is difficult...

  2. Mineral fibre persistence and carcinogenicity.

    Science.gov (United States)

    McDonald, J C

    1998-10-01

    Epidemiological research during the past 40 years has demonstrated with increasing clarity that amphibole asbestos fibres--crocidolite, amosite and tremolite--are more carcinogenic than chrysotile. A smaller number of well-controlled studies using lung burden analyses, while adding to the specificity of this conclusion, have shown that amphibole fibres also differ from chrysotile in being far more durable and biopersistent in lung tissue. Analyses of mesothelioma and lung cancer in a large cohort of Canadian chrysotile miners and millers have recently shown that the low-level presence of fibrous tremolite in these mines, rather than the chrysotile, may well be responsible. The high risk of lung cancer, but not of mesothelioma, in the chrysotile textile industry remains anomalous and cannot be explained in this way. These various findings are directly relevant to the choice of the experimental methods which should be used for screening man-made fibres for industrial use. Although it is clear that biopersistence is a major determinant of cancer risk in animals, and perhaps also in man, other factors affecting the biological activity of mineral fibres may also be important.

  3. Strength of Concrete Containing Basalt Fibre

    OpenAIRE

    2015-01-01

    This paper presents the comparative study of effect of basalt fibre on compressive and split tensile strength of M40 grade concrete. The basalt fibre was mixed in concrete by (0.5%, 1%, and 1.5%) of its total weight of cement in concrete. Results indicated that the strength increases with increase of basalt fibre content up to 1.0% beyond that there is a reduction in strength on increasing basalt fibre. The results show that the concrete specimen with 1.0% of basalt fibre gives be...

  4. Characterisation of Natural Fibre Reinforcements and Composites

    Directory of Open Access Journals (Sweden)

    Richard K. Cullen

    2013-01-01

    Full Text Available Recent EU directives (e.g., ELV and WEEE have caused some rethinking of the life cycle implications of fibre reinforced polymer matrix composites. Man-made reinforcement fibres have significant ecological implications. One alternative is the use of natural fibres as reinforcements. The principal candidates are bast (plant stem fibres with flax, hemp, and jute as the current front runners. The work presented here will consider the characterisation of jute fibres and their composites. A novel technique is proposed for the measurement of fibre density. The new rule of mixtures, extended for noncircular cross-section natural fibres, is shown to provide a sensible estimate for the experimentally measured elastic modulus of the composite.

  5. Frost resistance of fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    1999-01-01

    Frost resistance of fibre reinforced concrete with 2.5-4.2% air and 6-9% air (% by volume in fresh concrete) casted in the laboratory and in-situ is compared. Steel fibres with hooked ends (ZP, length 30 mm) and polypropylene fibres (PP, CS, length 12 mm) are applied. It is shown that· addition...... of 0.4-1% by volume of fibres cannot replace air entrainment in order to secure a frost resistant concrete; the minimum amount of air needed to make the concrete frost resistant is not changed when adding fibres· the amount of air entrainment must be increased when fibres are added to establish...... the same amount of air pores as in the corresponding concrete without fibres...

  6. Elastic fibres in health and disease.

    Science.gov (United States)

    Baldwin, Andrew K; Simpson, Andreja; Steer, Ruth; Cain, Stuart A; Kielty, Cay M

    2013-08-20

    Elastic fibres are insoluble components of the extracellular matrix of dynamic connective tissues such as skin, arteries, lungs and ligaments. They are laid down during development, and comprise a cross-linked elastin core within a template of fibrillin-based microfibrils. Their function is to endow tissues with the property of elastic recoil, and they also regulate the bioavailability of transforming growth factor β. Severe heritable elastic fibre diseases are caused by mutations in elastic fibre components; for example, mutations in elastin cause supravalvular aortic stenosis and autosomal dominant cutis laxa, mutations in fibrillin-1 cause Marfan syndrome and Weill-Marchesani syndrome, and mutations in fibulins-4 and -5 cause autosomal recessive cutis laxa. Acquired elastic fibre defects include dermal elastosis, whereas inflammatory damage to fibres contributes to pathologies such as pulmonary emphysema and vascular disease. This review outlines the latest understanding of the composition and assembly of elastic fibres, and describes elastic fibre diseases and current therapeutic approaches.

  7. Retained laser fibre: insights and management.

    Science.gov (United States)

    Lekich, C; Hannah, P

    2014-06-01

    To describe a case of retained endovenous laser fibre. To review the literature and Food and Drug Administration device failure reports. To suggest protocols for avoiding this complication and a method of removal. A case of retained fibre removal is described. Fibre removal techniques in vivo and ex vivo in a bovine model on the laboratory bench are presented. Successful in vivo and ex vivo fibre removal was performed using duplex ultrasound scan guided phlebectomy techniques. Unexplained measured fibre-length discrepancies due to misleading manufacturer's packaging was discovered. Simple ultrasound-guided micro-phlebectomy techniques can be used to remove retained laser fibres in the office environment. Laser fibre length measurements before and after treatment are recommended. Some preventive guidelines are described to avoid, or at least diagnose immediately, this complication, such as the 'Laser Eclipse Sign'. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  8. Simple method for manufacturing and optical characterization of tapered optical fibres

    Science.gov (United States)

    Zakrzewski, A.; Pięta, A.; Patela, S.

    2016-12-01

    Photonic devices often use light delivered by a single-mode telecommunication fibre. However, as the diameter of the core of the optical fibre is of 10 microns, and the transverse dimensions of the photonic waveguides are usually micrometer or less, there is an issue of incompatibility. The problem may be solved by application of tapered optical fibres. For efficient light coupling, the taper should be prepared so as to create a beam of long focal length and small spot diameter in the focus. The article describes the design, fabrication and characterization of tapered optical fibres prepared with a fibre-optic fusion splicer. We modelled the tapers with FDTD method, for estimation of the influence of the tapered length and angle on the spot diameter and the focal length of an outgoing beam. We fabricated tapers from a standard single mode fibre by the Ericsson 995 PMfi- bre-optic fusion splicer. We planned the splicing technology so as to get the needed features of the beam. We planned a multistep fusion process, with optimized fusion current and fusion time. The experimental measurements of best tapered optical fibres were carried out by the knife-edge method.

  9. Characterisation of Flax Fibres and Flax Fibre Composites. Being cellulose based sources of materials

    DEFF Research Database (Denmark)

    Aslan, Mustafa

    that currently have the largest market share for composite applications. However, the most critical limitation in the use of cellulosic fibre composites for structural applications is the lack of well described fibre properties, in particular, the tensile strength. This is due to variations in fibre morphology...... of the internal cell wall structures. This is in contrast to the crack growth in brittle ceramic and glass fibres. Moreover, two typical stress-strain curves (linear and non-linear) measured for the flax fibres were found to be correlated with the amount of defected region in the fibres. The defects are induced...... a similar microstructure at low fibre weight fractions. However, when the fibre content is increased, a difference in porosity content can be observed from the composite cross sections. The nominal tensile strength of the unidirectional flax fibre/LPET composites is measured in the range 180 to 340 MPa...

  10. The beginnings of vernacular scientific discourse: genres and linguistic features in some early issues of the Journal des Sçavans and the Philosophical Transactions

    Directory of Open Access Journals (Sweden)

    David BANKS

    2010-09-01

    knowledge. The Philosophical Transactions was founded by Henry Oldenberg, with a mandate, but without funding, from the Royal Society. It was based on the numerous letters that he received, and restricted itself to matters of “natural philosophy”. This article looks in detail at some of the linguistic features of one issue of the Journal des Sçavans (9 March 1665, and one issue of the Philosophical Transactions (3 July 1665. An analysis of transitivity patterns shows that relational process and verbal process constitute the most common types in the Journal des Sçavans, whereas in the Philosophical Transactions, although the rate of relational process is similar, the rate for material process is four times higher. An analysis of thematic structure shows that the Philosophical Transactions has rather less textual themes than the Journal des Sçavans. In terms of thematic progression, the Philosophical Transactions has slightly less linear links and rather more constant links than the Journal des Sçavans. A semantic categorization of themes shows that the most common categories in the Journal des Sçavans relate to the author of the book being reviewed, or to the book itself, whereas in the Philosophical Transactions the commonest category by far is the object of study.

  11. Fundamentals of fibre-reinforced soil engineering

    CERN Document Server

    Shukla, Sanjay Kumar

    2017-01-01

    This book is intended to serve as a one-stop reference on fibre-reinforced soils. Over the past 30-35 years, the engineering behaviour of randomly distributed/oriented fibre-reinforced soil, also called simply fibre-reinforced soil, has been investigated in detail by researchers and engineers worldwide. Waste fibres (plastic waste fibres, old tyre fibres, etc.) create disposal and environmental problems. Utilization of such fibres in construction can help resolve these concerns. Research studies and some field applications have shown that the fibres can be utilized in large quantities in geotechnical and civil engineering applications in a cost-effective and environmentally friendly manner. This book covers a complete description of fibres, their effects when included within a soil or other similar materials such as the fly ash, and their field applications. It gives a detailed view of fibre-reinforced soil engineering. The book will be useful to students, professional, and researchers alike, and can also ser...

  12. Structural investigation of Mimosa pudica Linn fibre

    Science.gov (United States)

    Patra, S. R.; Pattojoshi, P.; Tiwari, T. N.; Mallick, B.

    2016-12-01

    Sensitive plant (Mimosa pudica Linn.) fibre is a natural fibre with electrically conductive property. Because of its electro-active sensing nature, it has been found very interesting among physicists, chemists, biologists, material scientists and technologists. So far as our knowledge is concerned; there is no report on the X-ray structure of M. pudica fibre using diffraction technique. In the present report, the M. pudica fibre has been extracted from the stem of the herb by sinking the stem in 10% NaOH solution for one week. The diffraction pattern of the fibre is found out to be cellulose-I. The effect of the fibre structure and its orientation due to different mounting have been investigated using X-ray diffraction technique. The I max of cellulose-I has been observed along (002) and (10overline{1)} for the perpendicular and parallel mounting of the native-fibre, respectively. Full width at half maxima of the diffraction profile turns out to be decreased with fibre orientation. Dimension of crystallite size D hkl estimated in the perpendicular mounting D_{hkl}^{ bot } is more as compared to that of the parallel mounting D_{hkl}^{{^{allel } }} . The smallest crystallite sizes observed in both parallel and perpendicular mounting are 18.78 and 30.78 Å respectively. It is expected that the present study may help to analyse the X-ray diffraction of fibre materials in general and natural fibres in particular.

  13. Structural investigation of Mimosa pudica Linn fibre

    Science.gov (United States)

    Patra, S. R.; Pattojoshi, P.; Tiwari, T. N.; Mallick, B.

    2017-04-01

    Sensitive plant ( Mimosa pudica Linn.) fibre is a natural fibre with electrically conductive property. Because of its electro-active sensing nature, it has been found very interesting among physicists, chemists, biologists, material scientists and technologists. So far as our knowledge is concerned; there is no report on the X-ray structure of M. pudica fibre using diffraction technique. In the present report, the M. pudica fibre has been extracted from the stem of the herb by sinking the stem in 10% NaOH solution for one week. The diffraction pattern of the fibre is found out to be cellulose-I. The effect of the fibre structure and its orientation due to different mounting have been investigated using X-ray diffraction technique. The I max of cellulose-I has been observed along (002) and (10\\overline{1)} for the perpendicular and parallel mounting of the native-fibre, respectively. Full width at half maxima of the diffraction profile turns out to be decreased with fibre orientation. Dimension of crystallite size D hkl estimated in the perpendicular mounting D_{hkl}^{ \\bot } is more as compared to that of the parallel mounting D_{hkl}^{{^{allel } }}. The smallest crystallite sizes observed in both parallel and perpendicular mounting are 18.78 and 30.78 Å respectively. It is expected that the present study may help to analyse the X-ray diffraction of fibre materials in general and natural fibres in particular.

  14. Scientific issues in drug testing: council on scientific affairs

    Energy Technology Data Exchange (ETDEWEB)

    1987-06-12

    Testing for drugs in biologic fluids, especially urine, is a practice that has become widespread. The technology of testing for drugs in urine has greatly improved in recent years. Inexpensive screening techniques are not sufficiently accurate for forensic testing standards, which must be met wihen a person's employment or reputation may be affected by results. This is particularly a concern during screening of a population in which the prevalence of drug use is very low, in which the predictive value of a positive result would be quite low. Physicians should be aware that results from drug testing can yield accurate evidence of prior exposure to drugs, but they do not provide information about patterns of drug use, about abuse of or dependence on drugs, or about mental or physical impairments that may result from drug use.

  15. Fibre optic communication key devices

    CERN Document Server

    Grote, Norbert

    2017-01-01

    The book gives an in-depth description of key devices of current and next generation fibre optic communication networks. Devices treated include semiconductor lasers, optical amplifiers, modulators, wavelength filters and other passives, detectors, all-optical switches, but relevant properties of optical fibres and network aspects are included as well. The presentations include the physical principles underlying the various devices, technologies used for their realization, typical performance characteristics and limitations, but development trends towards more advanced components are also illustrated. This new edition of a successful book was expanded and updated extensively. The new edition covers among others lasers for optical communication, optical switches, hybrid integration, monolithic integration and silicon photonics. The main focus is on Indium phosphide-based structures but silicon photonics is included as well. The book covers relevant principles, state-of-the-art implementations, status of curren...

  16. 我国体育科学研究的合作网络演变与热点%Evolution and Hot Issues of the Collaboration Networks of the Sports Scientific Researches in China

    Institute of Scientific and Technical Information of China (English)

    苏宴锋; 司虎克

    2012-01-01

    On the basis of the collaboration of sports scientific research articles and by the methods of bibliometric analysis, social network analysis and statistics, the paper focuses on the collaboration networks and hot issues of China's sports science. The result shows that the collaborative researches in the fields of China's sports science are of a certain scale. The number of collaborative network nodes has been increasing year by year due to the collaborative researches. The structure of the networks are mainly single-point type and dual-core type, which shows high dis-connectivity. Many influential core authors and research collabo- rative groups are working actively in the fields of China's sports scientific researches. PE reform, multiple training, altitude training, technical and tactical analysis of the rivals in the Olympic Games and systematic construction of a sports power are the main hot issues in the recent-year sports scientific researches.%以体育科研论文合作为切入点,运用文献计量学分析、社会网络分析法、数理统计法等科学研究方法,对我国体育科学的合作网络与热点进行了探析。结果表明:我国体育科研领域的合作研究已具有一定规模,合作研究所形成的合作网络节点数量逐年增长;网络的结构类型以单点型与双核型为主,呈现出高度的不连通性;我国体育科学研究领域内活跃着一批具有较大影响力的核心作者以及科研合作团队,体育教学改革、"多元训练"、高原训练、奥运对手技战术分析、体育强国体系建设等研究是近来年体育科学研究中的热点问题。

  17. Fibre-reinforced calcium phosphate cements: a review.

    Science.gov (United States)

    Canal, C; Ginebra, M P

    2011-11-01

    Calcium phosphate cements (CPC) consist of one or more calcium orthophosphate powders, which upon mixing with water or an aqueous solution, form a paste that is able to set and harden after being implanted within the body. Different issues remain still to be improved in CPC, such as their mechanical properties to more closely mimic those of natural bone, or their macroporosity to favour osteointegration of the artificial grafts. To this end, blends of CPC with polymer and ceramic fibres in different forms have been investigated. The present work aims at providing an overview of the different approaches taken and identifying the most significant achievements in the field of fibre-reinforced calcium phosphate cements for clinical applications, with special focus on their mechanical properties.

  18. Scientific dissemination and creation about Young China · Issue on Relativity%《少年中国·相对论号》的科学传播与创造

    Institute of Scientific and Technical Information of China (English)

    白秀英; 姚远

    2011-01-01

    Aim From the history perspective of the scientific journals and communication, to research Young China ? Issue on Relativity, provide new clues for the dissemination of the relativity theory in China. Methods Analysis of the originals journals and research. Results Young China · Issue on Relativity created a number of innovations in spreading the relativity theory; It is the first to introduce the concept of the relativistic four-dimensional space-time to Chinese,using Einstein's( A. Einstein, 1879-1955) light-cone diagram. It is the first to express the principle of the maximum light speed by using mathematical deduction. It is the first to criticize that the object observed in the relativistic effect is flat. It is the first to introduce Salzburg meeting in which Einstein and the theory of relativity became an center of international physics. Conclusion Although Issue on Relativity contained only three articles, it had a high level of scientific accuracy in introducing the concept of relativity, mathematical deduction, and other aspects of the scientific connotation of time and space. It reduced the noise and distortion in the spread of the relativity theory. It had a very important scientific significance that relativity theory has become popular and its further social evolution.%目的 从科技期刊史和科学传播视角研究《少年中国·相对论号》,为相对论在中国早期传播提供新线索.方法 原始期刊分析与考证法.结果 《少年中国·相对论号》创造了相对论在中国传播的数个第一:刊载爱因斯坦(Alert Einstein,1879-1955)光锥图向国人介绍四维时空概念;表述光速最大原理的数学推论;对相对论尺缩效应下观测到的物体是瘦长形的图像进行批判;提及爱因斯坦及其学说成为国际物理界关注焦点的萨尔茨堡会议.结论 《少年中国·相对论号》虽然所载文章仅有3篇,但其对相对论概念介绍、数理推导以及时空观的科

  19. Electrospun cerium nitrate/polymer composite fibres:synthesis, characterization and fibre-division model

    Institute of Scientific and Technical Information of China (English)

    Li Meng-Meng; Long Yun-Ze; Yin Hong-Xing; Zhang Zhi-Ming

    2011-01-01

    Cerium (III)nitrate/poly(vinylpyrrolidone)(Ce(NO3)3/PVP)composite fibres have been prepared by electrospinning. After calcining the composite fibres in air at 500℃, CeO2 nanowires were obtained. The characterizations of the as-spun composite fibres and resultant nanowires have been carried out by a scanning electron microscope (SEM),an infrared spectrometer, an x-ray diffractometer and a fluorescence spectrophotometer. Interestingly, some unusual ribbon-like or twin fibres were observed besides the common fibres with circular or elliptic cross sections. We developed a fibre-division model resulting from Coulomb repulsion and solvent vaporization to interpret the formation of the ribbona or twin fibres, which has been confirmed by the SEM studies. Our results also indicate that the formation of the ribbons or twin fibres is less dependent on operation voltage and work distance.

  20. Orientation distribution of fibres in a channel flow of fibre suspension

    Institute of Scientific and Technical Information of China (English)

    Lin Jian-Zhong; Li Jun; Zhang Wei-Feng

    2005-01-01

    The orientation and concentration distributions of fibres in laminar and turbulent channel flows are investigated numerically. The obtained results are in good agreement with the experimental data. In the laminar flow regime, more fibres orient to the flow direction as the Reynolds number increases. The shear rate of fluid around a fibre plays an important role in determining the orientation distribution of fibres, while the fibre density and the fibre aspect-ratio have marginal influence on the orientation distribution. In the turbulent regime, the orientation distribution of fibres becomes more homogeneous with the increase of Reynolds number, and the concentration profile is flatter than that in the laminar regime. The fluctuating intensity of fibre velocity in the downstream direction is larger than that in the lateral directions.

  1. Interfacial Adhesion Characteristics of Kenaf Fibres Subjected to Different Polymer Matrices and Fibre Treatments

    Directory of Open Access Journals (Sweden)

    Umar Nirmal

    2014-01-01

    Full Text Available This study is aimed at determining the interfacial adhesion strength (IAS of kenaf fibres using different chemical treatments in hydrochloric (HCl and sodium hydroxide (NaOH with different concentrations. Single fibre pullout tests (SFPT were carried out for both untreated and treated fibres partially embedded into three different polymer matrices; polyester, epoxy, and polyurethane (PU as reinforcement blocks and tested under dry loading conditions. The study revealed that kenaf fibres treated with 6% NaOH subjected to polyester, epoxy, and PU matrices exhibits excellent IAS while poor in acidic treatment. The effect of SFPT results was mainly attributed to chemical composition of the fibres, types of fibre treatments, and variation in resin viscosities. By scanning electron microscopy examination of the material failure morphology, the fibres experienced brittle and ductile fibre breakage mechanisms after treatment with acidic and alkaline solutions.

  2. Frost resistance of fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    1999-01-01

    of 0.4-1% by volume of fibres cannot replace air entrainment in order to secure a frost resistant concrete; the minimum amount of air needed to make the concrete frost resistant is not changed when adding fibres· the amount of air entrainment must be increased when fibres are added to establish......Frost resistance of fibre reinforced concrete with 2.5-4.2% air and 6-9% air (% by volume in fresh concrete) casted in the laboratory and in-situ is compared. Steel fibres with hooked ends (ZP, length 30 mm) and polypropylene fibres (PP, CS, length 12 mm) are applied. It is shown that· addition...

  3. Muscle fibre type and aetiology of obesity.

    Science.gov (United States)

    Wade, A J; Marbut, M M; Round, J M

    1990-04-07

    Proportions of slow (type 1) muscle fibres of the vastus lateralis and percentage body fat were measured in 11 healthy sedentary men. The proportion of slow muscle fibres was inversely related to fatness; at least 40% of the variability in fatness may be related to variation in muscle fibre type. Metabolic evidence in 50 men, provided by the respiratory exchange ratio (RER) during cycle ergometry, indicated that fatter men (or, in the subset of 11 men, those with a low proportion of slow muscle fibres) combusted less fat during work at 100 W than did lean men (or those with a high proportion of slow fibres). The effects of fitness and of body size were excluded in the analysis. The evidence supports the hypothesis that muscle fibre type is an aetiological factor for obesity.

  4. Scientific news

    NARCIS (Netherlands)

    NN,

    1994-01-01

    The Rijksherbarium/Hortus Botanicus acquired funds through NWO (Netherlands Organisation for Scientific Research) to participate in a 7-year interdisciplinary cooperative programme of Indonesian and Dutch scientific institutions aiming at research in Irian Jaya, Cenderawasih province (the Bird’s Hea

  5. Expectations for a scientific collaboratory

    DEFF Research Database (Denmark)

    Sonnenwald, Diane H.

    2003-01-01

    with respect to scientific collaboratories. Interviews were conducted with 17 scientists who work in a variety of settings and have a range of experience conducting and managing scientific research. Results indicate that scientists expect a collaboratory to: support their strategic plans; facilitate management......In the past decade, a number of scientific collaboratories have emerged, yet adoption of scientific collaboratories remains limited. Meeting expectations is one factor that influences adoption of innovations, including scientific collaboratories. This paper investigates expectations scientists have...... of the scientific process; have a positive or neutral impact on scientific outcomes; provide advantages and disadvantages for scientific task execution; and provide personal conveniences when collaborating across distances. These results both confirm existing knowledge and raise new issues for the design...

  6. Expectations for a scientific collaboratory

    DEFF Research Database (Denmark)

    Sonnenwald, Diane H.

    2003-01-01

    with respect to scientific collaboratories. Interviews were conducted with 17 scientists who work in a variety of settings and have a range of experience conducting and managing scientific research. Results indicate that scientists expect a collaboratory to: support their strategic plans; facilitate management......In the past decade, a number of scientific collaboratories have emerged, yet adoption of scientific collaboratories remains limited. Meeting expectations is one factor that influences adoption of innovations, including scientific collaboratories. This paper investigates expectations scientists have...... of the scientific process; have a positive or neutral impact on scientific outcomes; provide advantages and disadvantages for scientific task execution; and provide personal conveniences when collaborating across distances. These results both confirm existing knowledge and raise new issues for the design...

  7. Continuous jute fibre reinforced laminated paper composite and reinforcement-fibre free paper laminate

    Indian Academy of Sciences (India)

    B B Verma

    2009-12-01

    Plastic bags create a serious environmental problem. The proposed jute fibre reinforced laminated paper composite and reinforcement-fibre free paper laminate may help to combat the war against this pollutant to certain extent. The paper laminate, without reinforcement fibre, exhibited a few fold superiority in tensile properties than single paper strip. The studies further show that an appreciable improvement in tensile properties can be achieved by introducing continuous jute fibre in paper laminates.

  8. Polymeric Optical Fibres for Biomedical Sensing

    OpenAIRE

    Krehel, M P

    2014-01-01

    In this thesis we focus on the integration of optical fibres in textiles to create wearable sensing systems. In the introduction (Chapter 3) we describe the basics of light guiding in optical fibres and methods of lateral light coupling. Subsequently, a literature review and motivation are presented. Afterwards two main parts can be differentiated. In the first one (Chapters 4, 5) a new method of continuous extrusion of optical fibres and their medical sensing application using photoplethysmo...

  9. THERMAL AND ENVIRONMENTAL EFFECTS ON CERAMIC FIBRES

    OpenAIRE

    Karlsson, S.; Lundberg, R.; Carlsson, R.

    1986-01-01

    Fibre insulations in kilns in the ceramic industry were investigated. Cristobalite and mullite are the main crystalline phases found in Al2O3-SiO2 fibres. The amount of the crystalline phases formed depends on the chemical composition and firing temperature. Condensation of ZnO-vapours from the glaze and formation of ZnAl2O4 were found in a Saffil fibre at a temperature of 930°C.

  10. A novel photonic crystal fibre switch

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard; Hermann, D.S.; Broeng, Jes

    2003-01-01

    A new thermo-optic fibre switch is demonstrated, which utilizes the phase transitions of a thermochromic liquid crystal inside a photonic crystal fibre. We report an extinction ratio of 60 dB and an insertion loss of 1 dB.......A new thermo-optic fibre switch is demonstrated, which utilizes the phase transitions of a thermochromic liquid crystal inside a photonic crystal fibre. We report an extinction ratio of 60 dB and an insertion loss of 1 dB....

  11. Abaca fibre reinforced PP composites and comparison with jute and flax fibre PP composites

    Directory of Open Access Journals (Sweden)

    2007-11-01

    Full Text Available Abaca fibre reinforced PP composites were fabricated with different fibre loadings (20, 30, 40, 50wt% and in some cases 35 and 45 wt%. Flax and jute fibre reinforced PP composites were also fabricated with 30 wt% fibre loading. The mechanical properties, odour emission and structure properties were investigated for those composites. Tensile, flexural and Charpy impact strengths were found to increase for fibre loadings up to 40 wt% and then decreased. Falling weight impact tests were also carried out and the same tendency was observed. Owing to the addition of coupling agent (maleated polypropylene -MAH-PP, the tensile, flexural and falling weight impact properties were found to increase in between 30 to 80% for different fibre loadings. When comparing jute and flax fibre composites with abaca fibre composites, jute fibre composites provided best tensile properties but abaca fibre polypropylene composites were shown to provide best notch Charpy and falling weight impact properties. Odours released by flax fibre composites were smaller than jute and abaca fibre composites.

  12. A validation of the fibre orientation and fibre length attrition prediction for long fibre-reinforced thermoplastics

    Science.gov (United States)

    Hopmann, Ch.; Weber, M.; van Haag, J.; Schöngart, M.

    2015-05-01

    To improve the mechanical performance of polymeric parts, fibre reinforcement has established in industrial applications during the last decades. Next to the widely used Short Fibre-reinforced Thermoplastics (SFT) the use of Long Fibre-reinforced Thermoplastics (LFT) is increasingly growing. Especially for non-polar polymeric matrices like polypropylene (PP), longer fibres can significantly improve the mechanical performance. As with every kind of discontinuous fibre reinforcement the fibre orientations (FO) show a high impact on the mechanical properties. On the contrary to SFT where the local fibre length distribution (FLD) can be often neglected, for LFT the FLD show a high impact on the material's properties and has to be taken into account in equal measure to the FOD. Recently numerical models are available in commercial filling simulation software and allow predicting both the local FOD and FLD in LFT parts. The aim of this paper is to compare i.) the FOD results and ii) the FLD results from available orientation- and fibre length attrition-models to those obtained from experimental data. The investigations are conducted by the use of different injection moulded specimens made from long glass fibre reinforced PP. In order to determine the FOD, selected part sections are examined by means of Computed Tomographic (CT) analyses. The fully three dimensional measurement of the FOD is then performed by digital image processing using grey scale correlation. The FLD results are also obtained by using digital image processing after a thermal pyrolytic separation of the polymeric matrix from the fibres. Further the FOD and the FLD are predicted by using a reduced strain closure (RSC) as well as an anisotropic rotary diffusion - reduced strain closure model (ARD-RSC) and Phelps-Tucker fibre length attrition model implemented in the commercial filling software Moldflow, Autodesk Inc., San Rafael, CA, USA.

  13. A validation of the fibre orientation and fibre length attrition prediction for long fibre-reinforced thermoplastics

    Energy Technology Data Exchange (ETDEWEB)

    Hopmann, Ch.; Weber, M.; Haag, J. van; Schöngart, M. [Institute of Plastics Processing (IKV) at RWTH Aachen University, Pontstr. 49, 52062 Aachen (Germany)

    2015-05-22

    To improve the mechanical performance of polymeric parts, fibre reinforcement has established in industrial applications during the last decades. Next to the widely used Short Fibre-reinforced Thermoplastics (SFT) the use of Long Fibre-reinforced Thermoplastics (LFT) is increasingly growing. Especially for non-polar polymeric matrices like polypropylene (PP), longer fibres can significantly improve the mechanical performance. As with every kind of discontinuous fibre reinforcement the fibre orientations (FO) show a high impact on the mechanical properties. On the contrary to SFT where the local fibre length distribution (FLD) can be often neglected, for LFT the FLD show a high impact on the material’s properties and has to be taken into account in equal measure to the FOD. Recently numerical models are available in commercial filling simulation software and allow predicting both the local FOD and FLD in LFT parts. The aim of this paper is to compare i.) the FOD results and ii) the FLD results from available orientation- and fibre length attrition-models to those obtained from experimental data. The investigations are conducted by the use of different injection moulded specimens made from long glass fibre reinforced PP. In order to determine the FOD, selected part sections are examined by means of Computed Tomographic (CT) analyses. The fully three dimensional measurement of the FOD is then performed by digital image processing using grey scale correlation. The FLD results are also obtained by using digital image processing after a thermal pyrolytic separation of the polymeric matrix from the fibres. Further the FOD and the FLD are predicted by using a reduced strain closure (RSC) as well as an anisotropic rotary diffusion - reduced strain closure model (ARD-RSC) and Phelps-Tucker fibre length attrition model implemented in the commercial filling software Moldflow, Autodesk Inc., San Rafael, CA, USA.

  14. Plant Fibre: Molecular Structure and Biomechanical Properties, of a Complex Living Material, Influencing Its Deconstruction towards a Biobased Composite

    Directory of Open Access Journals (Sweden)

    Mathias Sorieul

    2016-07-01

    Full Text Available Plant cell walls form an organic complex composite material that fulfils various functions. The hierarchical structure of this material is generated from the integration of its elementary components. This review provides an overview of wood as a composite material followed by its deconstruction into fibres that can then be incorporated into biobased composites. Firstly, the fibres are defined, and their various origins are discussed. Then, the organisation of cell walls and their components are described. The emphasis is on the molecular interactions of the cellulose microfibrils, lignin and hemicelluloses in planta. Hemicelluloses of diverse species and cell walls are described. Details of their organisation in the primary cell wall are provided, as understanding of the role of hemicellulose has recently evolved and is likely to affect our perception and future study of their secondary cell wall homologs. The importance of the presence of water on wood mechanical properties is also discussed. These sections provide the basis for understanding the molecular arrangements and interactions of the components and how they influence changes in fibre properties once isolated. A range of pulping processes can be used to individualise wood fibres, but these can cause damage to the fibres. Therefore, issues relating to fibre production are discussed along with the dispersion of wood fibres during extrusion. The final section explores various ways to improve fibres obtained from wood.

  15. Surface treated polypropylene (PP) fibres for reinforced concrete

    Energy Technology Data Exchange (ETDEWEB)

    López-Buendía, Angel M., E-mail: buendia@uv.es [AIDICO Technological Institute of Construction, Benjamin Franklin 17, 46380 Paterna, Valencia (Spain); Romero-Sánchez, María Dolores [AIDICO Technological Institute of Construction, Marble Technical Unit, Camí de Castella 4, 03660 Novelda. Alicante (Spain); Climent, Verónica [Lafarge Cementos, Polígono Sepes, Isaac Newton s/n, 46500 Sagunto, Valencia (Spain); Guillem, Celia [AIDICO Technological Institute of Construction, Marble Technical Unit, Camí de Castella 4, 03660 Novelda. Alicante (Spain)

    2013-12-15

    Surface treatments on a polypropylene (PP) fibre have contributed to the improvement of fibre/concrete adhesion in fibre-reinforced concrete. The treatments to the PP fibre were characterized by contact angle measurements, ATR-IR and XPS to analyse chemical alterations. The surface topography and fibre/concrete interaction were analysed by several microscopic techniques, namely optical petrographic, and scanning electron microscopy. Treatment modified the surface chemistry and topography of the fibre by introducing sodium moieties and created additional fibre surface roughness. Modifications in the fibre surface led to an increase in the adhesion properties between the treated fibres and concrete and an improvement in the mechanical properties of the fibre-reinforced concrete composite as compared to the concrete containing untreated PP fibres. Compatibility with the concrete and increased roughness and mineral surface was also improved by nucleated portlandite and ettringite mineral association anchored on the alkaline PP fibre surface, which is induced during treatment.

  16. The Dependance of Damage Accumulation in Carbon Fibre Reinforced Epoxy Composites on Matrix Properties.

    Science.gov (United States)

    1985-12-01

    Diguuibutiofl Unlimited 0- Contract U.S. AIR FORCE/ARMINES- Centre des Matdriaux No A.F.O.S.R. 84-0397 - Final Report December 1985 THE DEPENDANCE OF DAMAGE...61102F 2301 D1 185 11 TITLE (include Security Classification) THE DEPENDANCE OF DAMAGE ACCUMULATION IN CARBON FIBRE REINFORCED EPOXY COMPOSITES ON...ATN OF: LTS/Autovon 235-4299 26 March 1986 SUBJECT: EOARD-TR-86-04, Final Scientific Report, "The Dependance of Damage Accumu- lation in Carbon Fibre

  17. Planetary Environments: Scientific Issues and Perspectives

    Directory of Open Access Journals (Sweden)

    Encrenaz Th.

    2014-02-01

    Full Text Available What are the planetary environments where conditions are best suited for habitability? A first constraint is provided by the presence of liquid water. This condition allows us to define two kinds of media: (1 the atmospheres of solid (exoplanets with a temperature typically ranging between 0°C and 100°C, and (2 the interiors of icy bodies (outer satellites or possibly exosatellites where the pressure and temperature would fit the liquid phase region of the water phase diagram. In the case of Mars, significant progress has been achieved about our understanding of the history of liquid water in the past, thanks to the findings of recent space missions. The study of the outer satellites is also benefiting from the on-going operation of the Cassini mission. In the case of exopl nets, new discoveries are continuously reported, especially with the Kepler mission, in operation since 2009. With the emergence of transit spectroscopy, a new phase of exoplanets’ exploration has started, their characterization, opening the new field of exoplanetology. In the future, new perspectives appear regarding the exploration of Mars, the giant planets and exoplanets, with the ultimate goal of characterizing the atmospheres of temperate exoplanets.

  18. Electrical Characterization of Silicon Cores from Glass-Cladded Fibres

    OpenAIRE

    Lapointe, Kyle

    2014-01-01

    Semiconductor core fibres represent an emerging technology with potential applications in many areas, including photovoltaics and optical transmission. Recent advances in fibre manufacturing techniques has allowed long, continuous silicon core fibres to be produced in commercial draw towers. The effect of the molten core fibre fabrication method on the electrical properties of silicon cores from glass-clad fibres have been studied. Fibres with core diameters ranging from 60 to 300 µm wer...

  19. Postponed sowing does not alter the fibre/wood ratio or fibre extractability of fibre hemp (Cannabis sativa)

    NARCIS (Netherlands)

    Westerhuis, W.; Struik, P.C.; Dam, van J.E.G.; Stomph, T.J.

    2009-01-01

    Because hemp is a short-day plant, postponing the sowing date might be a suitable strategy to obtain shorter and smaller plants around flowering, when primary fibres are 'ripe' enough to be harvested. Smaller plants can be processed on existing flax scutching and hackling lines and might have fibre

  20. On the Measurement of the Electrical Power Produced by Melt Spun Piezoelectric Textile Fibres

    Science.gov (United States)

    Matsouka, Dimitroula; Vassiliadis, Savvas; Prekas, Kleanthis; Bayramol, Derman Vatansever; Soin, Navneet; Siores, Elias

    2016-10-01

    Piezoelectric, melt spun, textile fibres as multifunctional materials appeared recently, and they are under thorough investigation and testing in order to define their performance and behaviour. Although piezoelectricity was first reported in 1880 and the piezoelectric behaviour of organic polymers materials has been known since 1969, the fibrous form of the piezoelectric materials under consideration opens new technological horizons; however, it introduces novel restrictions and further complex parameters are involved in their study. The major issue of the current research work is the study of the actual capacity of the piezoelectric fibres, i.e. the electric power produced following mechanical stimulation of the individual fibre. The measurements were made possible after the development of the necessary specific equipment. The test results enabled the ranking of the various types of the piezoelectric fibres according to the respective power generation. The main difference in this research approach is the measurement of the power generated by the fibres. Measurement of the power generated by an electrical power source (in the case of energy harvesting applications which is the prime interest of this research project) is an important characteristic as the requirements of various applications are expressed in units of power. Stating the voltage produced during mechanical deformation of the fibres is not enough (cf. voltage produced due to electrostatic phenomena on textiles where the voltage is in the range is the several kV, but the power is not enough to power a light-emitting diode).

  1. Shrinking of bumps by drawing scintillating fibres through a hot conical tool

    CERN Document Server

    Rodrigues Cavalcante, Ana Barbara; Gavardi, Laura; Joram, Christian; Kristic, Robert; Pierschel, Gerhard; Schneider, Thomas

    2016-01-01

    The LHCb SciFi tracker will be based on scintillating fibres with a nominal diameter of 250 $\\mu$m. A small length fraction of these fibres shows millimetre-scale fluctuations of the diameter, also known as bumps and necks. In particular, bumps exceeding a diameter of about 350 $\\mu$m are problematic as they can distort the winding pattern of the fibre mats over more extended regions. We present a method to reduce the diameter of large bumps to a diameter of 350 $\\mu$m by locally heating and pulling the fibre through a conical tool. The method has been proven to work for bumps up to 450 – 500 $\\mu$m diameter. Larger bumps need to be treated manually by a cut-and-glue technique which relies on UV-curing instant glue. The bump shrinking and cut-and-glue processes were integrated in a fibre diameter scanner at CERN. The central scanning and bump shrinking of all fibres is expected to minimise bump related issues at the four mat winding centres of the SciFi project.

  2. Precision single mode fibre integral field spectroscopy with the RHEA spectrograph

    Science.gov (United States)

    Rains, Adam D.; Ireland, Michael J.; Jovanovic, Nemanja; Feger, Tobias; Bento, Joao; Schwab, Christian; Coutts, David W.; Guyon, Olivier; Arriola, Alexander; Gross, Simon

    2016-08-01

    The RHEA Spectrograph is a single-mode echelle spectrograph designed to be a replicable and cost effective method of undertaking precision radial velocity measurements. Two versions of RHEA currently exist, one located at the Australian National University in Canberra, Australia (450 - 600nm wavelength range), and another located at the Subaru Telescope in Hawaii, USA (600 - 800 nm wavelength range). Both instruments have a novel fibre feed consisting of an integral field unit injecting light into a 2D grid of single mode fibres. This grid of fibres is then reformatted into a 1D array at the input of the spectrograph (consisting of the science fibres and a reference fibre capable of receiving a white-light or xenon reference source for simultaneous calibration). The use of single mode fibres frees RHEA from the issue of modal noise and significantly reduces the size of the optics used. In addition to increasing the overall light throughput of the system, the integral field unit allows for cutting edge science goals to be achieved when operating behind the 8.2m Subaru Telescope and the SCExAO adaptive optics system. These include, but are not limited to: resolved stellar photospheres; resolved protoplanetary disk structures; resolved Mira shocks, dust and winds; and sub-arcsecond companions. We present details and results of early tests of RHEA@Subaru and progress towards the stated science goals.

  3. Multicore optical fibre and fibre-optic delay line based on it

    Science.gov (United States)

    Egorova, O. N.; Astapovich, M. S.; Belkin, M. E.; Semjonov, S. L.

    2016-12-01

    The first switchable fibre-optic delay line based on a 1300-{\\text{m}}-long multicore optical fibre has been fabricated and investigated. We have obtained signal delay times of up to 45 \\unicode{956}{\\text{s}} at 6.43-\\unicode{956}{\\text{s}} intervals. Sequential signal propagation through the cores of the multicore optical fibre makes it possible to reduce the fibre length necessary for obtaining a predetermined delay time, which is important for reducing the weight and dimensions of devices based on the use of fibre-optic delay lines.

  4. Polarisation effects in twin-core fibre: Application for mode locking in a fibre laser

    Energy Technology Data Exchange (ETDEWEB)

    Lobach, I A; Kablukov, S I; Podivilov, Evgenii V; Babin, Sergei A; Apolonski, A A

    2012-09-30

    We report the first measurements of the longitudinal power distribution in a twin-core optical fibre at different input light polarisations. Experimental evidence is presented that, because of the difference in birefringence between the cores, the power in them depends on which core the beam is launched into. Experimental data are interpreted in terms of a modified polarisation model for mode coupling in twin-core fibres which takes into account the birefringence of the cores. In addition, we demonstrate for the first time the use of the polarisation properties of a twincore fibre for mode locking in a fibre laser. (optical fibres, lasers and amplifiers. properties and applications)

  5. TIDAL CYCLING DYNAMIC OF BIOGENIC GASES EMISSION: KEY SCIENTIFIC ISSUES AND UNCERTAINTY%生源气体排放的潮周期动态研究:关键科学问题与不确定性

    Institute of Scientific and Technical Information of China (English)

    王进欣; 王今殊; 钦佩; 张维康

    2011-01-01

    Biogenic gases emission is an important aspect of study on global C, N, S. and Cl cycles. It has been a main focus of global change ecology and biogeochemical cycle research. In this paper firstly type of biogenic gases and their environmental effects are introduced, then key scientific issues and uncertainty of study on tidal cycling dynamic of biogenic gases emission are reviewed, especially status and focus of future research in the fields of biogenic gases emission. Discussion of key scientific issues and uncertainty of study on tidal cycling dynamic of biogenic gases emission can help us better understand tides and control factors of the biogenic gases production, conversion, and migration interaction. It is more important to reveal interaction among C, N, S, and Cl in order to provide insight and theoretical founda-tion for alleviation of greenhouse effects.%生态系统生源气体排放是全球C、N、S和Cl循环研究的重要内容,是当前全球变化生态学和生物地球化学循环的研究热点和焦点.在介绍海岸带盐沼生态系统生源气体种类及其环境效应的的基础上,重点对潮汐循环对植物枯落物分解和土壤生源要素生态化学计量学特征的影响、潮汐循环影响下电子受体和盐分输入特征及其对生源气体排放的影响、潮汐循环影响下生源气体生产者生态生理特征和生产者贡献比率变化特征、潮汐循环影响下海岸带盐沼高等植物根际生理生态过程以及海岸带盐沼潮周期内生源气体通量特征及其相互关系等关键科学问题和这些问题研究中的不确定性进行了探讨.为揭示C、N、S和Cl元素之间的相互作用及平衡制约关系和为减缓温室效应提供新思路和理论依据具有重要的现实意义.

  6. 大洋性柔鱼类资源开发现状及可持续利用的科学问题%Current exploitation and some scientific issues in the sustainable utilization of Ommastrephidae

    Institute of Scientific and Technical Information of China (English)

    陈新军; 陆化杰; 刘必林; 田思泉

    2012-01-01

    大洋性柔鱼类是重要的渔业资源,商业性开发的种类主要有太平洋褶柔鱼、柔鱼、阿根廷滑柔鱼、茎柔鱼和双柔鱼等。据统计,1992-2010年柔鱼类产量占世界头足类的比重稳定在51.15%~62.19%,平均达到55.40%。对重要柔鱼种类的资源现状及开发状况进行系统分析,根据大洋性柔鱼类生命周期短、生长快等特点,提出了4项需研究的问题,即:(1)全面了解大洋性柔鱼类的生态地位和作用;(2)全面掌握环境包括全球气候变化对大洋性柔鱼类资源补充量的影响;(3)深入研究大洋性柔鱼类短生命周期资源评估模式;(4)发展基于生态系统的大洋性柔鱼类资源管理方法。%The oceanic Ommastrephidae is an important cephalopod resource.The main species which have been exploited at the large-scale commercial development included Todarodes pacificus,Illex argentinus,Dosidicus gigas,Nototodarus sloani and Symplectoteuthis oualaniensis.According to the data statistics during 1992 to 2010,the Ommastrephidae production accounted for 51.15%-62.19% of cephalopods in the world,with an average of 55.40%.In this paper,the current exploitation and resources conditions of Todarodes pacificus,Illex argentinus,Dosidicus gigas and other squids are described in details.Meanwhile,according to the biological characteristics of short life cycle and fast growth,four major scientific issues which are to be resolved have been put forward.The four scientific issues are:(1) a completely comprehensive understanding of the ecological status and role of Ommastrephidae;(2) fully mastering the effect of environment including global climate change on the recruitment of Ommastrephidae;(3) further study of assessment model for Ommastrephidae based on the short life cycle;and(4) developing the ecosystem-based resource management approaches for Ommastrephidae.

  7. Investigation on effect of fibre hybridization and orientation on mechanical behaviour of natural fibre epoxy composite

    Indian Academy of Sciences (India)

    P KALIAPPAN; R KESAVAN; B VIJAYA RAMNATH

    2017-08-01

    Nowadays bio fibre composites play a vital role by replacing conventional materials used in automotive andaerospace industries owing to their high strength to weight ratio, biodegradability and ease of production. This paper aimsto find the effect of fibre hybridization and orientation on mechanical behaviour of composite fabricated with neem, abacafibres and epoxy resin. Here, three varieties of composites are fabricated namely, composite 1 which consists of abaca fibreand glass fibre, composite 2, which consists of neem fibre and glass fibre, whereas composite 3 consists of abaca, neem fibresand glass fibres. In all the above three varieties, fibres are arranged in three types of orientations namely, horizontal (type I),vertical (type II) and 45$^{\\circ}$ inclination (type III). The result shows that composites made up of abaca and neem fibres withinclined orientation (45$^{\\circ}$) have better mechanical properties when compared with other types of composites. In addition, morphological analysis is carried out using scanning electron microscope to know the fibre distribution, fibre pull out, fibre breakage and crack propagation on tested composites.

  8. Influence of fibre volume fraction and temperature on fatigue life of glass fibre reinforced plastics

    Directory of Open Access Journals (Sweden)

    Konrad Wegener

    2016-07-01

    Full Text Available The influence of fibre volume fraction and temperature on fatigue life of continuous glass fibre reinforced plastics is investigated in detail. The physical causes of the two effects on the slope of the S-N-curve in fibre direction at R = 0.1 are researched and can be explained with help of micrographs. A new phenomenological approach is presented to model both effects in fibre dominated laminates with different stacking sequences using only the static ultimate strength as an input. Static and fatigue tests of different layups and fibre volume fractions are performed at different temperatures to validate the fatigue life predictions. Additionally it is derived that there is an optimal fibre volume fraction regarding a minimum damage sum. This fibre volume fraction is dependent on a given loading spectra and can be calculated using the phenomenological model.

  9. Ethical Issues and Countermeasures in the Clinical Scientific Research on Hepatitis B%乙型肝炎临床科研中的伦理问题及措施

    Institute of Scientific and Technical Information of China (English)

    关鑫; 纪文利; 朱抗美; 樊民胜

    2012-01-01

    National Ministry of Public Health issued "The notice of protection of rights of admission and employment among the carriers of Hepatitis B Surface Antigen" in 2010. Since then, the test of Hepatitis was canceled before admission and employment. Consequently we are going to take another consideration for people with this specific kind of disease. There are some special ethical issues when we take this group of people into clinical scientific researches, such as vulnerable problem, qualification of PI, ratio of risk and benefic, SAE, etc. Ethical committee should take some related measures to protect the subjects. Suggestions raised in this paper include further perfecting the procedure of informed consent in order to improve the research subjects'understanding towards the experiment, enhancing the ratio of tracking review, especially for the risk management of SAE, strengthening the handling of adverse reaction, and promoting on - spot review by incorporating ethical ward round in hospitals.%为了更好地保护乙型肝炎临床科研中的受试者,通过探讨受试者为弱势人群的伦理问题、研究人员和伦理审查人员资质的伦理问题、受试者招募的伦理问题、对照选择的伦理问题和风险与受益比的伦理问题等,提出伦理委员会加强伦理过程管理的相关措施:完善知情同意的过程,提高受试者的理解度;提高跟踪审查频率,尤其加强SAE的风险管理;加强不良反应的处理;结合开展医院“伦理查房”,推进现场检查.

  10. Mohair, cashmere and other animal hair fibres

    CSIR Research Space (South Africa)

    Hunter, L

    2012-11-01

    Full Text Available Although luxury animal fibres, excluding silk, represent far less than 0.1% of global fibre production, they play a very significant role in the luxury, high value-added end of the market, notably the apparel market, being renowned for their special...

  11. low pump power photonic crystal fibre amplifiers

    DEFF Research Database (Denmark)

    Hougaard, Kristian G.; Broeng, Jes; Bjarklev, Anders Overgaard

    2003-01-01

    Designs of low pump power optical amplifiers, based on photonic crystal fibres are presented. The potential of these fibre amplifiers is investigated, and it is demonstrated that such amplifiers may deliver gains of more than 15 dB at 1550 nm with less than 1 mW of optical pump power....

  12. The development of fibre optic microbend sensors

    NARCIS (Netherlands)

    Horsthuis, W.H.G.; Fluitman, J.H.J.

    1983-01-01

    Investigations concerning the development of a fibre optic pressure sensor are reported. The phenomenon of light power attenuation in a periodically deformed graded index fibre has been studied theoretically. It appears that available theories are not suited to describe this attenuation process in t

  13. Multifunctional Carbon Fibre Tapes for Automotive Composites

    Science.gov (United States)

    Koncherry, V.; Potluri, P.; Fernando, A.

    2016-11-01

    Cabon fibre composites are used where mechanical performance such as strength, stiffness and impact properties at low density is a critical parameter for engineering applications. Carbon fibre flat tape is one material which is traditionally used to manufacture three-dimensional composites in this area. Modifying the carbon fibre tape to incorporate other functions such as stealth, electromagnetic interference, shielding, de-icing, self-repair, energy storage, allows us to create multi-functional carbon fibre tape. Researchers have been developing such material and the technology for their manufacture in order to produce multifunctional carbon fibre based components more economically and efficiently. This paper presents the manufacturing process of a metallised carbon fibre material for a chopped fibre preforming process that uses electromagnets for preforming instead of traditional suction airflow fibre deposition. In addition, the paper further presents mechanical and magneto-static modelling that is carried out to investigate the bending properties of the material produced and its suitability for creating 3D preforms.

  14. Dispersion properties of photonic Bandgap Fibres

    DEFF Research Database (Denmark)

    Broeng, Jes; Barkou, Stig Eigil; Søndergaard, Thomas

    1999-01-01

    Dispersion properties of new low-index core photonic crystal fibres are presented. Both wideband nearzero despersion and very large dispersion is shown possible in the 1550 nm wavelength range.......Dispersion properties of new low-index core photonic crystal fibres are presented. Both wideband nearzero despersion and very large dispersion is shown possible in the 1550 nm wavelength range....

  15. Selective filling of Photonic Crystal Fibres

    DEFF Research Database (Denmark)

    Nielsen, Kristian; Noordegraaf, Danny; Sørensen, Thorkild

    2005-01-01

    A model for calculating the time necessary for filling one or more specific holes in a photonic crystal fibre is made. This model is verified for water, and its enabling potential is illustrated by a polymer application. Selective filling of the core in an air-guide photonic crystal fibre...

  16. Strength variability of single flax fibres

    DEFF Research Database (Denmark)

    Aslan, Mustafa; Chinga-Carrasco, G.; Sørensen, Bent F.

    2011-01-01

    (linear and nonlinear) of the fibres are found to be correlated with the amount of defects. The linear stress–strain curves tend to show a higher tensile strength, a higher Young’s modulus, and a lower strain to failure than the nonlinear curves. Finally, the fibres are found to fracture by a complex...

  17. Thermally induced structural changes in Nomex fibres

    Indian Academy of Sciences (India)

    Anjana Jain; Kalyani Vijayan

    2002-08-01

    Thermally aged Nomex fibres manifest several residual effects viz. reduction in X-ray crystallinity, weight loss and deterioration in tensile characteristics. Surface damages in the form of longitudinal openings, holes, material deposits etc have also been observed. Based on the data from thermally exposed fibres, the time needed for states of zero tensile strength and modulus have been predicted.

  18. Fibre optic cables for the ALICE experiment

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    These thin fibres will transmit the signal received in detectors at the ALICE experiment when it starts up with the LHC in 2008. The analogue signals produced in the detectors are first converted into digital pulse, which are transported in light down such fibres. Computers then read this digital signal to produce the final set of data.

  19. Cotton fibre cross-section properties

    Science.gov (United States)

    From a structural perspective the cotton fibre is a singularly discrete, elongated plant cell with no junctions or inter-cellular boundaries. Its form in nature is essentially unadulterated from the field to the spinning mill where its cross-section properties, as for any textile fibre, are central ...

  20. Fibre positioning algorithms for the WEAVE spectrograph

    NARCIS (Netherlands)

    Terrett, David L.; Lewis, Ian J.; Dalton, Gavin; Abrams, Don Carlos; Aguerri, J. Alfonso L.; Bonifacio, Piercarlo; Middleton, Kevin; Trager, Scott C.

    2014-01-01

    WEAVE is the next-generation wide-field optical spectroscopy facility for the William Herschel Telescope (WHT) in La Palma, Canary Islands, Spain. It is a multi-object "pick and place" fibre fed spectrograph with more than one thousand fibres, similar in concept to the Australian Astronomical Observ

  1. Winding of fibre composites; Vikling af fiberkompositter

    Energy Technology Data Exchange (ETDEWEB)

    Lystrup, Aage

    2006-01-01

    Within the project 'Storage of hydrogen in advanced high pressure vessels' under the PSO-R AND D 2005 program one of the tasks is to describe the technology, which is used for manufacturing of fibre reinforced pressure vessels. Fibre reinforced pressure vessels for high pressures are manufactured by winding structural load bearing fibres around a mandrel or an internal liner. There are two different types of cylindrical pressure vessels: 1) Cylinders with thick metal liner, where only the cylindrical part is over wrapped with hoop windings, and 2) cylinders with a thin metal or polymer liner, where both the cylindrical part and the end domes are over wrapped with more layers with different fibre orientations (helical and hoop windings). This report describes the fundamental principles for filament winding of fibre reinforced polymer composites. After a short introduction to the advanced fibre composites, their properties and semi-raw materials used for fibre composites, the focus is on the process parameters, which have influence on the material quality of filament wound components. The report is both covering winding of fibre reinforced thermo-setting polymers as well as thermoplastic polymers, and there are references to vendors of filament winding machines, accessory equipment and computer software for design and manufacturing of filament wound components. (au)

  2. Selective filling of Photonic Crystal Fibres

    DEFF Research Database (Denmark)

    Nielsen, Kristian; Noordegraaf, Danny; Sørensen, Thorkild

    2005-01-01

    A model for calculating the time necessary for filling one or more specific holes in a photonic crystal fibre is made. This model is verified for water, and its enabling potential is illustrated by a polymer application. Selective filling of the core in an air-guide photonic crystal fibre is demo...

  3. Development of the fibres of MOONS

    Science.gov (United States)

    Guinouard, Isabelle; Lee, David; Schnetler, Hermine; Taylor, William; Amans, Jean-Philippe; Montgomery, David; Oliva, Ernesto

    2014-07-01

    MOONS will exploit the full 500 square arcmin field of view offered by the Nasmyth focus of the Very Large Telescope and will be equipped with two identical triple arm cryogenic spectrographs covering the wavelength range 0.8 - 1.8 μm, with a multiplex capability of approximately 1000 fibres. Each triple arm spectrograph will produce spectra for half of the targets simultaneously. The system will have both a medium resolution (R~4000-6000) mode and a high resolution (R~20000) mode. The fibres are used to pick off each sub field of 1.05 arcseconds and are used to transport the light from the instrument focal plane to the two spectrographs. Each fibre has a microlens to focus the beam into the fibre at a relative fast focal ratio of F/3.65 to reduce the Focal Ratio Degradation (FRD). This paper presents the overall design of the fibre system and describes the specific developments required to optimise its performance. The design of the fibre input optics, the choice of the fibre connector, and the layout of the slit end are described. The results of preliminary tests to measure the effect of twisting on the FRD performance of prototype fibres are also discussed.

  4. Innovations with protein nano-fibres

    NARCIS (Netherlands)

    Linden, van der E.

    2006-01-01

    Proteins in solution can form objects of various shapes. One fascinating possibility is the formation of fibres with a length up to micrometers, but with a thickness of a few nanometers, therefore referring to them as nano-fibres. Many proteins show this behaviour under the appropriate conditions. G

  5. Winding of fibre composites; Vikling af fiberkompositter

    Energy Technology Data Exchange (ETDEWEB)

    Lystrup, Aage

    2006-01-01

    Within the project 'Storage of hydrogen in advanced high pressure vessels' under the PSO-R AND D 2005 program one of the tasks is to describe the technology, which is used for manufacturing of fibre reinforced pressure vessels. Fibre reinforced pressure vessels for high pressures are manufactured by winding structural load bearing fibres around a mandrel or an internal liner. There are two different types of cylindrical pressure vessels: 1) Cylinders with thick metal liner, where only the cylindrical part is over wrapped with hoop windings, and 2) cylinders with a thin metal or polymer liner, where both the cylindrical part and the end domes are over wrapped with more layers with different fibre orientations (helical and hoop windings). This report describes the fundamental principles for filament winding of fibre reinforced polymer composites. After a short introduction to the advanced fibre composites, their properties and semi-raw materials used for fibre composites, the focus is on the process parameters, which have influence on the material quality of filament wound components. The report is both covering winding of fibre reinforced thermo-setting polymers as well as thermoplastic polymers, and there are references to vendors of filament winding machines, accessory equipment and computer software for design and manufacturing of filament wound components. (au)

  6. Durability of cracked fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place; Nielsen, Laila

    1997-01-01

    (capillary water uptake) is used, involving an in-situ method and a laboratory method. Three different concrete qualities as well as steel fibres (ZP) and polypropylene fibres (PP) are used. Results of the durability tests on cracked FRC-beams are compared to results for uncracked FRC-beams and beams without...

  7. Image analysis of insulation mineral fibres.

    Science.gov (United States)

    Talbot, H; Lee, T; Jeulin, D; Hanton, D; Hobbs, L W

    2000-12-01

    We present two methods for measuring the diameter and length of man-made vitreous fibres based on the automated image analysis of scanning electron microscopy images. The fibres we want to measure are used in materials such as glass wool, which in turn are used for thermal and acoustic insulation. The measurement of the diameters and lengths of these fibres is used by the glass wool industry for quality control purposes. To obtain reliable quality estimators, the measurement of several hundred images is necessary. These measurements are usually obtained manually by operators. Manual measurements, although reliable when performed by skilled operators, are slow due to the need for the operators to rest often to retain their ability to spot faint fibres on noisy backgrounds. Moreover, the task of measuring thousands of fibres every day, even with the help of semi-automated image analysis systems, is dull and repetitive. The need for an automated procedure which could replace manual measurements is quite real. For each of the two methods that we propose to accomplish this task, we present the sample preparation, the microscope setting and the image analysis algorithms used for the segmentation of the fibres and for their measurement. We also show how a statistical analysis of the results can alleviate most measurement biases, and how we can estimate the true distribution of fibre lengths by diameter class by measuring only the lengths of the fibres visible in the field of view.

  8. Interfaces between a fibre and its matrix

    Science.gov (United States)

    Lilholt, H.; Sørensen, B. F.

    2017-07-01

    The interface between a fibre and its matrix represents an important element in the characterization and exploitation of composite materials. Both theoretical models and analyses of experimental data have been presented in the literature since modern composite were developed and many experiments have been performed. A large volume of results for a wide range of composite systems exists, but rather little comparison and potential consistency have been reached for fibres and/or for matrices. Recently a materials mechanics approach has been presented to describe the interface by three parameters, the interfacial energy [J/m2], the interfacial frictional shear stress [MPa] and the mismatch strain [-] between fibre and matrix. The model has been used for the different modes of fibre pull-out and fibre fragmentation. In this paper it is demonstrated that the governing equations for the experimental parameters (applied load, debond length and relative fibre/matrix displacement) are rather similar for these test modes. A simplified analysis allows the direct determination of the three interface parameters from two plots for the experimental data. The complete analysis is demonstrated for steel fibres in polyester matrix. The analysis of existing experimental literature data is demonstrated for steel fibres in epoxy matrix and for tungsten wires in copper matrix. These latter incomplete analyses show that some results can be obtained even if all three experimental parameters are not recorded.

  9. Microstructural characterization of stone wool fibre network

    DEFF Research Database (Denmark)

    Chapelle, Lucie; Brøndsted, Povl; Kusano, Yukihiro;

    2014-01-01

    Understanding the mechanical properties of fibrous network as complex as stone wool materials requires a relevant description of their microstructure and architecture. In this study, different methods have been proposed to characterize the fibre orientation, diameter and length of fibres as well...

  10. Insertion of optic fibre for CMS

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    The MicroJET system uses high pressure to carefully put the optical fibres into their protective tubes. These fibres are vital for rapid data transfer, but are also very delicate and, if damanged, may not work at the required efficiency. Similiar methods are used to install cables for the telecommunications industry.

  11. Recent advances in poled optical fibres

    DEFF Research Database (Denmark)

    Pruneri, V.; Margulis, W.; Myrén, N.

    2005-01-01

    A second-order nonlinearity can be induced in optical fibres through poling. We describe accomplishments of the EU project GLAMOROUS in making low-cost high performance electrooptic and nonlinear optical fibre- and waveguide-based components. In particular a comparison with more traditional...

  12. Recent advances in poled optical fibres

    DEFF Research Database (Denmark)

    Pruneri, V.; Margulis, W.; Myrén, N.;

    2005-01-01

    A second-order nonlinearity can be induced in optical fibres through poling. We describe accomplishments of the EU project GLAMOROUS in making low-cost high performance electrooptic and nonlinear optical fibre- and waveguide-based components. In particular a comparison with more traditional...

  13. Fibre Distribution in Friction-spun Yarns

    Institute of Scientific and Technical Information of China (English)

    Eric Oyondi Nganyi; YU Chong-wen

    2006-01-01

    According to the yarn forming characteristics in friction spinning, the arrangement of fed sliver is designed, to get the desired fiber distribution in the resultant yarn. On the base of that, the relation between the theoretical fibre distribution and the actual fibre distribution is analyzed by use of electron microscope.

  14. Processing, structure and flexural strength of CNT and carbon fibre reinforced, epoxy-matrix hybrid composite

    Indian Academy of Sciences (India)

    K Chandra Shekar; M Sai Priya; P K Subramanian; Anil Kumar; B Anjaneya Prasad; N Eswara Prasad

    2014-05-01

    Advanced materials such as continuous fibre-reinforced polymer matrix composites offer significant enhancements in variety of properties, as compared to their bulk, monolithic counterparts. These properties include primarily the tensile stress, flexural stress and fracture parameters. However, till date, there are hardly any scientific studies reported on carbon fibre (Cf) and carbon nanotube (CNT) reinforced hybrid epoxy matrix composites (unidirectional). The present work is an attempt to bring out the flexural strength properties along with a detailed investigation in the synthesis of reinforced hybrid composite. In this present study, the importance of alignment of fibre is comprehensively evaluated and reported. The results obtained are discussed in terms of material characteristics, microstructure and mode of failure under flexural (3-point bend) loading. The study reveals the material exhibiting exceptionally high strength values and declaring itself as a material with high strength to weight ratio when compared to other competing polymer matrix composites (PMCs); as a novel structural material for aeronautical and aerospace applications.

  15. A Review of Refractometric Sensors Based on Long Period Fibre Gratings

    Directory of Open Access Journals (Sweden)

    G. Rego

    2013-01-01

    Full Text Available In the last decade refractometric sensors have attracted an increasing interest by the scientific community due to their ability to perform ambient monitoring, to assess food quality and safety, and also to the fact that they enable the development of label free sensors in the biomedical area. These advances result, namely, from the use of long period fibre gratings in the turning points and/or with thin films in the transition region that allows resolutions of 10−6 to changes in the refractive index of the surrounding medium. Resolutions exceeding 10−8 can also be achieved when long period fibre gratings are combined with evanescent field based devices. This paper reviews the recent path towards the development of ultrahigh sensitive optical fibre refractometric sensors.

  16. A review of refractometric sensors based on long period fibre gratings.

    Science.gov (United States)

    Rego, G

    2013-01-01

    In the last decade refractometric sensors have attracted an increasing interest by the scientific community due to their ability to perform ambient monitoring, to assess food quality and safety, and also to the fact that they enable the development of label free sensors in the biomedical area. These advances result, namely, from the use of long period fibre gratings in the turning points and/or with thin films in the transition region that allows resolutions of 10(-6) to changes in the refractive index of the surrounding medium. Resolutions exceeding 10(-8) can also be achieved when long period fibre gratings are combined with evanescent field based devices. This paper reviews the recent path towards the development of ultrahigh sensitive optical fibre refractometric sensors.

  17. Metal-coated Bragg grating reflecting fibre

    Science.gov (United States)

    Chamorovskiy, Yu. K.; Butov, O. V.; Kolosovskiy, A. O.; Popov, S. M.; Voloshin, V. V.; Vorob'ev, I. L.; Vyatkin, M. Yu.

    2017-03-01

    High-temperature optical fibres (OF) with fibre Bragg gratings (FBG) arrays written over a long length and in-line metal coating have been made for the first time. The optical parameters of the FBG arrays were tested by the optical frequency domain reflectometer (OFDR) method in a wide temperature range, demonstrating no degradation in reflection at heating up to 600 °C for a fibre with Al coating. The mechanical strength of the developed fibre was practically the same as "ordinary" OF with similar coating, showing the absence of the influence of FBG writing process on fibre strength. Further experiments are necessary to evaluate the possibility of further increases in the operational temperature range.

  18. CONFERENCE NOTE: CETO—Centro de Ciências e Tecnologias Opticas, Trends in Optical Fibre Metrology and Standards

    Science.gov (United States)

    1994-01-01

    Summer School, 27 June to 8 July 1994, Viana do Castelo, Hotel do Parque, Portugal Optical fibres, with their extremely low transmission loss, untapped bandwidth and controllable dispersion, dominate a broad range of technologies in which applications must respond to the increasing constraints of today's specifications as well as envisage future requirements. Optical fibres dominate communications systems. In the area of sensors, fibre optics will be fully exploited for their immunity to EMI, their high sensitivity and their large dynamic range. The maturity of single mode optical technology has led to intensive R&D of a range of components based on the advantages of transmission characteristics and signal processing. Specifications and intercompatibility requests for the new generation of both analogue and digital fibre optical components and systems has created a demand for sophisticated measuring techniques based on unique and complex instruments. In recent years there has been a signification evolution in response to the explosion of applications and the tightening of specifications. These developments justify a concerted effort to focus on trends in optical fibre metrology and standards. Objective The objective of this school is to provide a progressive and comprehensive presentation of current issues concerning passive and active optical fibre characterization and measurement techniques. Passive fibre components support a variety of developments in optical fibre systems and will be discussed in terms of relevance and standards. Particular attention will be paid to devices for metrological purposes such as reference fibres and calibration artefacts. The characterization and testing of optical fibre amplifiers, which have great potential in telecommunications, data distribution networks and as a system part in instrumentation, will be covered. Methods of measurement and means of calibration with traceability will be discussed, together with the characterization

  19. EDITORIAL: The 19th International Conference on Optical Fibre Sensors, OFS-19 The 19th International Conference on Optical Fibre Sensors, OFS-19

    Science.gov (United States)

    Sampson, David D.; Jones, Julian D. C.; Tatam, Ralph P.

    2009-03-01

    OFS-19 was held in April 2008 in Perth, Australia, with Professor David Sampson (University of Western Australia) as General Chair assisted by Technical Programme Co-Chairs Professor Stephen Collins (Victoria University, Australia), Professor Kyunghwan Oh (Yonsei University, Korea) and Dr Ryozo Yamauchi (Fujikura Ltd, Japan). 'OFS-19' has once again affirmed the OFS series as the leading international conference for the optical fibre sensor community. Since its inception, in London in 1983, and under the leadership of an international steering committee independent of any learned society or professional institution, it has been held approximately every eighteen months. The venue nominally rotates from Europe, to the Americas, and thence to Asia and the Pacific. OFS-19 demonstrated the continuing vigour of the community, with some 240 papers presented, plus 8 tutorials; submissions and attendance were from 29 countries, with a little over half coming from the Asia-Pacific Region. In recent years, it has become a tradition to publish a post-conference special issue in Measurement Science and Technology, and these special issues offer a representative sample of the current status of the field. In the 25 years since OFS began, many of the early ideas and laboratory-based proof-of-principle experiments have successfully evolved into highly developed instrumentation systems and commercial products. One of the greatest success stories has been the optical fibre Bragg grating. Its exquisite intrinsic sensitivity to temperature and strain has led to an expanding niche in structural monitoring, especially in civil engineering. It has formed the 'beach-head' for penetration of optical fibre sensors into the oil and gas industry, initially in the harsh environment of down-hole monitoring. Latterly, it has paved the way for new applications of one of the earliest fibre optic sensors, the fibre hydrophone, which is now making its mark in sub-sea seismic surveying. Additionally

  20. Review article: dietary fibre-microbiota interactions.

    Science.gov (United States)

    Simpson, H L; Campbell, B J

    2015-07-01

    Application of modern rapid DNA sequencing technology has transformed our understanding of the gut microbiota. Diet, in particular plant-based fibre, appears critical in influencing the composition and metabolic activity of the microbiome, determining levels of short-chain fatty acids (SCFAs) important for intestinal health. To assess current epidemiological, experimental and clinical evidence of how long-term and short-term alterations in dietary fibre intake impact on the microbiome and metabolome. A Medline search including items 'intestinal microbiota', 'nutrition', 'diet', 'dietary fibre', 'SCFAs' and 'prebiotic effect' was performed. Studies found evidence of fibre-influenced differences in the microbiome and metabolome as a consequence of habitual diet, and of long-term or short-term intervention (in both animals and humans). Agrarian diets high in fruit/legume fibre are associated with greater microbial diversity and a predominance of Prevotella over Bacteroides. 'Western'-style diets, high in fat/sugar, low in fibre, decrease beneficial Firmicutes that metabolise dietary plant-derived polysaccharides to SCFAs and increase mucosa-associated Proteobacteria (including enteric pathogens). Short-term diets can also have major effects, particularly those exclusively animal-based, and those high-protein, low-fermentable carbohydrate/fibre 'weight-loss' diets, increasing the abundance of Bacteroides and lowering Firmicutes, with long-term adherence to such diets likely increasing risk of colonic disease. Interventions to prevent intestinal inflammation may be achieved with fermentable prebiotic fibres that enhance beneficial Bifidobacteria or with soluble fibres that block bacterial-epithelial adherence (contrabiotics). These mechanisms may explain many of the differences in microbiota associated with long-term ingestion of a diet rich in fruit and vegetable fibre. © 2015 The Authors. Alimentary Pharmacology & Therapeutics published by John Wiley & Sons Ltd.

  1. Scientific communication

    Directory of Open Access Journals (Sweden)

    Aleksander Kobylarek

    2017-09-01

    Full Text Available The article tackles the problem of models of communication in science. The formal division of communication processes into oral and written does not resolve the problem of attitude. The author defines successful communication as a win-win game, based on the respect and equality of the partners, regardless of their position in the world of science. The core characteristics of the process of scientific communication are indicated , such as openness, fairness, support, and creation. The task of creating the right atmosphere for science communication belongs to moderators, who should not allow privilege and differentiation of position to affect scientific communication processes.

  2. Effects of fibre content on mechanical properties and fracture behaviour of short carbon fibre reinforced geopolymer matrix composites

    Indian Academy of Sciences (India)

    Tiesong Lin; Dechang Jia; Meirong Wang; Peigang He; Defu Liang

    2009-02-01

    Geopolymer matrix composites reinforced with different volume fractions of short carbon fibres (Cf/geopolymer composites) were prepared and the mechanical properties, fracture behaviour and microstructure of as-prepared composites were studied and correlated with fibre content. The results show that short carbon fibres have a great strengthening and toughening effect at low volume percentages of fibres (3.5 and 4.5 vol.%). With the increase of fibre content, the strengthening and toughening effect of short carbon fibres reduce, possibly due to fibre damage, formation of high shear stresses at intersect between fibres and strong interface cohesion of fibre/matrix under higher forming pressure. The property improvements are primarily based on the network structure of short carbon fibre preform and the predominant strengthening and toughening mechanisms are attributed to the apparent fibre bridging and pulling-out effect.

  3. Knowledge about dietary fibre: a fibre study framework.

    Science.gov (United States)

    Guiné, Raquel P F; Ferreira, Manuela; Correia, Paula; Duarte, João; Leal, Marcela; Rumbak, Ivana; Barić, Irena C; Komes, Drazenka; Satalić, Zvonimir; Sarić, Marijana M; Tarcea, Monica; Fazakas, Zita; Jovanoska, Dijana; Vanevski, Dragoljub; Vittadini, Elena; Pellegrini, Nicoletta; Szűcs, Viktória; Harangozó, Júlia; El-Kenawy, Ayman; El-Shenawy, Omnia; Yalçın, Erkan; Kösemeci, Cem; Klava, Dace; Straumite, Evita

    2016-09-01

    The objective of this work was to study the degree of knowledge about dietary fibre (DF), as influenced by factors such as gender, level of education, living environment or country. For this, a descriptive cross-sectional study was undertaken on a non-probabilistic sample of 6010 participants from 10 countries in different continents (Europe, Africa and America). The results showed that the participants revealed on average a positive but still low global level of knowledge, which alerts for the need to take some actions to further inform the population about DF and its role as a component of a healthy diet. The results also indicated differences between genders, levels of education, living environments and countries. The highest level of knowledge was revealed by the participants from female gender, with higher education and living in urban areas. Concerning the country, the best informed were the participants from Romania, followed by those from Portugal and Turkey while the least informed were from Egypt.

  4. Fluoro-edenite and carbon nanotubes: The health impact of ‘asbestos-like’ fibres

    Science.gov (United States)

    MIOZZI, EDOARDO; RAPISARDA, VENERANDO; MARCONI, ANDREA; COSTA, CHIARA; POLITO, IRENE; SPANDIDOS, DEMETRIOS A.; LIBRA, MASSIMO; FENGA, CONCETTINA

    2016-01-01

    Several decades have passed since Wagner et al demonstrated a causal link between asbestos fibre inhalation and the development of pleural mesothelioma in 1960. It was later suggested that pleural plaques are a benign consequence of exposure to these fibres. Most recently, a significant association between exposure to asbestos and cancer diagnosed at various sites, such as the peritoneum, stomach, pharynx, colon and ovaries has been demonstrated. The great concerns about public health that arose from the scientific evidence presented above have led to the banning of asbestos in several countries. Over the years, the suspicion that particles with a high aspect ratio may have asbestos-like pathogenicity has been supported by increasing evidence. Natural occurring minerals, as well as man-made fibres, have proven capable of inducing either chronic inflammation of serous membranes, or, in some cases, the development of peritoneal and pleural mesothelioma. The pathogenic role of both fluoro-edenite and carbon nanotubes, two ‘asbestos-like’ fibres is summarized and discussed in this review. The data presented herein support the notion that occupational exposure to these two types of fibre contributes to the development of different types of cancer. PMID:26889212

  5. Fluoro-edenite and carbon nanotubes: The health impact of 'asbestos-like' fibres.

    Science.gov (United States)

    Miozzi, Edoardo; Rapisarda, Venerando; Marconi, Andrea; Costa, Chiara; Polito, Irene; Spandidos, Demetrios A; Libra, Massimo; Fenga, Concettina

    2016-01-01

    Several decades have passed since Wagner et al demonstrated a causal link between asbestos fibre inhalation and the development of pleural mesothelioma in 1960. It was later suggested that pleural plaques are a benign consequence of exposure to these fibres. Most recently, a significant association between exposure to asbestos and cancer diagnosed at various sites, such as the peritoneum, stomach, pharynx, colon and ovaries has been demonstrated. The great concerns about public health that arose from the scientific evidence presented above have led to the banning of asbestos in several countries. Over the years, the suspicion that particles with a high aspect ratio may have asbestos-like pathogenicity has been supported by increasing evidence. Natural occurring minerals, as well as man-made fibres, have proven capable of inducing either chronic inflammation of serous membranes, or, in some cases, the development of peritoneal and pleural mesothelioma. The pathogenic role of both fluoro-edenite and carbon nanotubes, two 'asbestos-like' fibres is summarized and discussed in this review. The data presented herein support the notion that occupational exposure to these two types of fibre contributes to the development of different types of cancer.

  6. PROSCENIUM OF SCIENTIFIC MANAGEMENT

    OpenAIRE

    Vasile Berlingher

    2013-01-01

    During the last three decades of the nineteenth century, organizations developed rapidly, their managers began to realize that they had too frequent managerial problems; this awareness lead to a new phase of development of scientific management. Examining the titles published in that period, it can be concluded that management issues that pose interest related to payroll and payroll systems, problems exacerbated by the industrial revolution and related work efficiency. Noting that large or...

  7. Comparison of Acoustic Characteristics of Date Palm Fibre and Oil Palm Fibre

    Directory of Open Access Journals (Sweden)

    Lamyaa Abd ALRahman

    2014-02-01

    Full Text Available This study investigated and compared the acoustic characteristics of two natural organic fibres: date palm fibre and oil palm fibre, these materials eligible for acoustical absorption. During the processing stage, both fibre sheets are treated with latex. The two fibres are compressed after latex treatment Circular samples (100 mm in diameter and 28 mm, based on the measurement tube requirements are cut out of the sheets. The density of the date palm fibre sheet is 150 kg/m3 for a 50 mm thickness and 130 kg/m3 for a 30 mm thickness. In contrast, the density of oil palm fibre is 75 kg/m3 for a 50 mm thickness and 65 kg/m3 for a 30 mm thickness. An impedance tube was used to test the thicknesses of both samples based on international standards. The results show that the date palm fibre exhibits two Acoustic Absorption Coefficient (AAC peaks: 0.93 at 1356 Hz and 0.99 at 4200-4353 Hz for the 50-mm-thick sample. In contrast, the 30-mm-thick sample has a single AAC peak of 0.83 at 2381.38-2809.38 Hz. However, the 50-mm-thick oil palm fibre has an AAC peak of 0.75 at 1946.88-2178.13 Hz and the 30-mm-thick oil palm fibre has an acoustic absorption coefficient peak 0.59 at 3225-3712.5 Hz. Thus, the date palm fibre has a higher acoustic absorption coefficient for high and low frequencies than does oil palm fibre. Both fibres are promising for use as sound absorber materials to protect against environmental noise pollution.

  8. Ductility Performance of Hybrid Fibre Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    S. Eswari

    2008-01-01

    Full Text Available This study presents a study on the ductility performance of hybrid fibre reinforced concrete. The influence of fibre content on the ductility performance of hybrid fibre reinforced concrete specimens having different fibre volume fractions was investigated. The parameters of investigation included modulus of rupture, ultimate load, service load, ultimate and service load deflection, crack width, energy ductility and deflection ductility. A total of 27 specimens, 100×100×500 mm, were tested to study the above parameters. The specimens incorporated 0.0 to 2.0% volume fraction of polyolefin and steel fibres in different proportions. The ductility performance of hybrid fibre reinforced concrete specimens was compared with that of plain concrete. The test results show that addition of 2.0% by volume of hybrid fibres improves the ductility performance appreciably. An adaptive Neuro-Fuzzy based model has been proposed to predict the ductility performance characteristics. A reasonably close agreement has been obtained between the experimental and predicted results.

  9. Controllable spatiotemporal nonlinear effects in multimode fibres

    Science.gov (United States)

    Wright, Logan G.; Christodoulides, Demetrios N.; Wise, Frank W.

    2015-05-01

    Multimode fibres are of interest for next-generation telecommunications systems and the construction of high-energy fibre lasers. However, relatively little work has explored nonlinear pulse propagation in multimode fibres. Here, we consider highly nonlinear ultrashort pulse propagation in the anomalous-dispersion regime of a graded-index multimode fibre. Low modal dispersion and strong nonlinear coupling between the fibre's many spatial modes result in interesting behaviour. We observe spatiotemporal effects reminiscent of nonlinear optics in bulk media—self-focusing and multiple filamentation—at a fraction of the usual power. By adjusting the spatial initial conditions, we generate on-demand, megawatt, ultrashort pulses tunable between 1,550 and 2,200 nm dispersive waves over one octave; intense combs of visible light; and a multi-octave-spanning supercontinuum. Our results indicate that multimode fibres present unique opportunities for observing new spatiotemporal dynamics and phenomena. They also enable the realization of a new type of tunable, broadband fibre source that could be useful for many applications.

  10. Ceramic fibres for the automotive industry

    Energy Technology Data Exchange (ETDEWEB)

    Fryatt, J.

    1985-01-01

    The outstanding thermal, physical and chemical properties of ceramic fibres make them a noticeable contender for inclusion in engineered systems to satisfy such performance demands. A wide range of fibres and fibre-based products are available which exhibit such characteristics as high temperature continuous service ability (1600/sup 0/C if required), low thermal conductivity, excellent resistance to chemical attack (including reducing conditions), good acoustic performance at all temperatures and good resistance to vibration. They are also lightweight, fireproof and incombustible. Ceramic fibres should really be referred to as refractory fibres as they are based on combinations of high purity alumina and silica. Two groups of products exist. The most common have a continuous-use temperature of 1260/sup 0/C. These fibres are characterized by an alumina content of 40-50% but refractoriness and temperature use limit can be increased to about 1400/sup 0/C by modifying the basic chemistry. This generally involves increasing the alumina content to as much as 62% or adding chromia or zirconia to the basic mix. The second and less common group of fibres is characterized by both chemistry and crystal morphology. Chemistry is biased towards a high alumina content (over 70%), while production routes are designed to yield as high a crystal phase (and so enhanced high temperature stability) as possible.

  11. Comparison of two novel approaches to model fibre reinforced concrete

    NARCIS (Netherlands)

    Radtke, F.K.F.; Simone, A.; Sluys, L.J.

    2009-01-01

    We present two approaches to model fibre reinforced concrete. In both approaches, discrete fibre distributions and the behaviour of the fibre-matrix interface are explicitly considered. One approach employs the reaction forces from fibre to matrix while the other is based on the partition of unity f

  12. Coherent Beam Combination of Two Polarization Maintaining Ytterbium Fibre Amplifiers

    Institute of Scientific and Technical Information of China (English)

    HOU Jing; XIAO Rui; JIANG Zong-Fu; CHENG Xiang-Ai; SHU Bai-Hong; CHEN Jin-Bao; LIU Ze-Jin

    2005-01-01

    @@ We investigate coherent beam combination of fibre laser beams by phase locking. Phase noise of a polarization maintaining ytterbium fibre amplifier is inspected with a fibre interferometer. In a feed back control loop, two fibre polarization maintaining ytterbium amplifiers are phase locked and coherent combined when the phase noise is properly controlled by a LiNO3 phase modulator.

  13. On modelling of physical effects accompanying the propagation of action potentials in nerve fibres

    CERN Document Server

    Engelbrecht, Jüri; Tamm, Kert; Laasmaa, Martin; Vendelin, Marko

    2016-01-01

    The recent theoretical and experimental studies have revealed many details of signal propagation in nervous systems. In this paper an attempt is made to unify various mathematical models which describe the signal propagation in nerve fibres. The analysis of existing single models permits to select the leading physiological effects. As a result, a more general mathematical model is described based on the coupling of action potentials with mechanical waves in a nerve fibre. The crucial issue is how to model coupling effects which are strongly linked to the ion currents through biomembranes.

  14. VIRUS: assembly, testing and performance of 33,000 fibres for HETDEX

    Science.gov (United States)

    Kelz, Andreas; Jahn, Thomas; Haynes, D.; Hill, G. J.; Lee, H.; Murphy, J. D.; Neumann, Justus; Nicklas, Harald; Rutowska, M.; Sandin, C.; Streicher, O.; Tuttle, S.; Fabricius, M.; Bauer, S. M.; Vattiat, B.; Anwand, H.; Savage, R.

    2014-07-01

    VIRUS is the visible, integral-field replicable unit spectrograph for the Hobby-Eberly-Telescope (HET) consisting of 75 integral-field-units that feed 150 spectrographs. The full VIRUS instrument features over 33,000 fibres, each projecting to 1.5 arcseconds diameter on sky, deployed at the prime focus of the upgraded 10m HET. The assembly and acceptance testing for all IFUs includes microscopic surface quality inspections, astrometry of fibre positions, relative throughput measurements, focal-ratio-degradation evaluation, and system acceptance using a VIRUS reference spectrograph to verify the image quality, spectral transmission, stability, or to detect any stray light issues.

  15. Nonlinear microstructured polymer optical fibres

    DEFF Research Database (Denmark)

    Frosz, Michael Henoch

    . The combination of a small core size and zero-dispersion wavelength at the operating wavelength of widely available femtosecond Ti:sapphire lasers led to an extensive research in supercontinuum generation and other nonlinear effects in PCFs. It is crucial for the efficiency of many nonlinear mechanisms...... that the pump laser wavelength is close to the zero-dispersion wavelength and that the core size is small. Recently, work in fabricating PCFs from materials other than silica has intensified. One of the advantages of using alternative materials can be a higher inherent material nonlinearity, which...... to accurately obtain a small core size while maintaining small structural variations during fibre drawing. This talk will give a presentation of how the mPOFs are fabricated and the route to obtaining nonlinear effects in them....

  16. Radiation tolerance tests of scintillating fibres

    Energy Technology Data Exchange (ETDEWEB)

    Gavardi, Laura; Albrecht, Johannes [TU Dortmund (Germany); Collaboration: LHCb-Collaboration

    2016-07-01

    An upgrade of the LHCb detector is planned during the shutdown which will take place from mid 2018 to the end of 2019. The proposed upgrade for the tracking system is a detector composed of scintillating fibres read out by silicon photomultipliers. The tracking detector will be working in an environment exposed to radiation, so that the resistance of the fibres to radiation is an important quality, which needs to be investigated. In this talk tests of scintillating fibres tolerance to radiation will be presented.

  17. Analysing the nanoporous structure of aramid fibres

    DEFF Research Database (Denmark)

    Pauw, Brian Richard; Vigild, Martin Etchells; Mortensen, Kell;

    2010-01-01

    After consideration of the applicability of classical methods, a novel analysis method for the characterization of fibre void structures is presented, capable of fitting the entire anisotropic two-dimensional scattering pattern to a model of perfectly aligned, polydisperse ellipsoids. It is tested...... for validity against the computed scattering pattern for a simulated nanostructure, after which it is used to fit the scattering from the void structure of commercially available heat-treated poly(p-phenylene terephtalamide) fibre and its as-spun precursor fibre. The application shows a reasonable fit...

  18. Silica holey fibres: fabrication and nonlinear effects

    OpenAIRE

    Belardi, W.; Monro, T.M.; Lee, J.H.; Yusoff, Z.; Price, J.H.V.; Malinowski, A.; Piper, A; Richardson, D J

    2002-01-01

    Holey fibres (HFs) [1] have emerged as a novel class of optical fibres which can provide completely new optical properties, such as endlessly single mode operation and novel dispersion properties as anomalous dispersion below 1.3µm, broadband flat dispersion and highly normal dispersion at 1.55µm. Moreover by changing the HF parameters (i.e. hole and core size), it is possible to fabricate HFs with an effective area so high as 800µm2 or so low as approximately 1µm2 [2]. A holey fibre perform ...

  19. Fibre Optic Protection System for Concrete Structures

    Institute of Scientific and Technical Information of China (English)

    J.S.Leng; A.Hameed; D.Winter; R.A.Barnes; G.C.Mays; G.F.Fernando

    2006-01-01

    The design concepts, modelling and implementation of various fibre optic sensor protection systems for development in concrete structures were investigated. Design concepts and on-site requirements for surface-mounted and embedded optical fibre sensor in concrete were addressed. Finite element (FE) modelling of selected sensor protection systems in strain-transfer efficiency from the structure to the sensing region was also studied. And experimental validation of specified sensor protection system was reported. Results obtained indicate that the protection system for the sensors performs adequately in concrete environment and there is very good correlation between results obtained by the protected fibre optic sensors and conventional electrical resistance strain gauges.

  20. Fibre optic power meter calibration uncertainties

    CSIR Research Space (South Africa)

    Nel, M

    2010-06-01

    Full Text Available thereof. It was done only for standard single mode fibre with FC (ferrule connector) connectors, and using a 1310 and a 1550 nm Fabry Perot laser (FP laser). The calibration set-up and procedure The uncertainty contributions for fibre optic power..., in this case 1310 or 1550 nm, is fed to the fibre optic power meter (secondary standard or unit under test (UUT)) via an attenuator. The attenuator serves to reduce back-reflections into the source and to set the power to the desired level. In Fig. 1...

  1. The coupling performance of photonic crystal fibres in fibre stellar interferometry

    DEFF Research Database (Denmark)

    Corbett, J.; Dabirian, A.; Butterley, T.;

    2006-01-01

    Large mode area (LMA), single-mode photonic crystal fibres (PCFs) have the potential to provide significant instrumental advantages in fibre stellar interferometry, due to their broadband attenuation spectrum, endlessly single-moded performance and very large core size. We investigate the theoret......Large mode area (LMA), single-mode photonic crystal fibres (PCFs) have the potential to provide significant instrumental advantages in fibre stellar interferometry, due to their broadband attenuation spectrum, endlessly single-moded performance and very large core size. We investigate...... the theoretical performance of coupling the telescope point spread function directly into LMA PCFs. We find that a single LMA fibre can replace as many as three step-index fibres for atmospheric seeing characterized by D-T/r(o) >= 2 with approximately the same coupling performance and a slower feed from...

  2. Rare-Earth Doped Photonic Crystal Fibre Lasers and Amplifiers

    DEFF Research Database (Denmark)

    Hougaard, Kristian G.

    2005-01-01

    In this thesis, a theoretical and numerical study of the use of rare-earthdoped photonic crystal fibres as optical amplifiers and lasers, has been performed. Photonic crystal fibres or microstructured optical fibres is a new kind of optical fibre in which the cladding region typically consist...... of a periodic microstructure, resulting in a fibre with very different properties compared to conventional optical fibres. The properties of photonic crystals fibres are described, with focus on the advantages this technology provides compared to conventional fibres, within the area of optical amplification....... The thesis also presents the basic properties of optical amplification, and describes the numerical model developed to model the behaviour of lasers and amplifiers based on photonic crystal fibres. The developed numerical tools are then used to investigate specific applications of photonic crystal fibres...

  3. Methodology for characterisation of glass fibre composite architecture

    DEFF Research Database (Denmark)

    Hansen, Jens Zangenberg; Larsen, J.B.; Østergaard, R.C.

    2012-01-01

    of the fibres. The information is used for different analyses to investigate and characterise the fibre architecture. As an example, the methodology is applied to glass fibre reinforced composites with varying fibre contents. The different fibre volume fractions (FVFs) affect the number of contact points per......The present study outlines a methodology for microstructural characterisation of fibre reinforced composites containing circular fibres. Digital micrographs of polished cross-sections are used as input to a numerical image processing tool that determines spatial mapping and radii detection...... fibre, the communal fibre distance and the local FVF. The fibre diameter distribution and packing pattern remain somewhat similar for the considered materials. The methodology is a step towards a better understanding of the composite microstructure and can be used to evaluate the interconnection between...

  4. A temperature-independent fibre-optic magnetic-field sensor using thin-core fibre tailored fibre Bragg grating

    Science.gov (United States)

    Tian, Qin; Feng, Zhongyao; Rong, Qiangzhou; Wan, Yun; Qiao, Xueguang; Hu, Manli; Yang, Hangzhou; Wang, Ruohui; Shao, Zhihua; Yang, Tingting

    2017-06-01

    A temperature-independent fibre-optic magnetic-field sensor is proposed and demonstrated experimentally. The device consists of a thin-core fibre (TCF) sandwiched in the upstream of a fibre Bragg grating (FBG). Because of the core-mismatch between the TCF and the single-mode fibre (SMF), the core mode is coupled to the cladding modes within the TCF cladding, and parts of them are recoupled back to the leading-in SMF by the downstream FBG. The cladding modes are sensitive to the ambient refractive index (RI), and therefore have the ability to respond to a RI change in the magnetic fluid determined by the ambient magnetic field. The intensities of the cladding-mode resonances are highly sensitive to the magnetic field change, while, in contrast, the resonance wavelengths always remain unchanged. This property can allow the sensor to act as a power-referenced reflection probe for magnetic field measurements.

  5. Key Scientific Issues on the Control of Foodborne Pathogens during Food Processing%食品加工过程中致病菌控制的关键科学问题

    Institute of Scientific and Technical Information of China (English)

    史贤明; 施春雷; 索标; 吴正云

    2011-01-01

    Foodbome pathogen is the top one cause for foodbome diseases, which is a key obstacle in the development of food safety control system in China. During food processing, foodbome pathogenic bacteria can survive in many stress conditions, such as heat, high pressure, frozen, desiccation, vacuum, oxidation and so on, for that they can become more resistant to these stresses through biofilm formation, recovery of sublethal injured cells and the regulatory of stress-related genes. Moreover, the secretion of some virulent factors such as thermanuclease and enterotoxin also threatens the safety of food processing. These key scientific issues on the control of foodbome pathogens related to food processing were reviewed in this article.%致病性细菌是导致食源性疾病暴发的罪魁祸首,也是我国建立食品质量安全控制体系必须面对的重要危害.在食品加工过程中,食源性致病菌由于能够形成菌膜,进行亚致死损伤修复,调节抗性基因的表达等,从而对加工过程中的高温、高压、冷冻、脱水、光照、真空以及氧化等环境胁迫产生耐受性.此外,致病菌也能够分泌各种胞外毒力因子等,给食品安全带来极大的威胁.本文针对近年来食品加工过程中致病菌安全控制关键科学问题的研究进展进行阐述,并对未来的发展方向作展望.

  6. Polymerizing the fibre between bacteria and host cells: the biogenesis of functional amyloid fibres

    OpenAIRE

    2008-01-01

    Amyloid fibres are proteinaceous aggregates associated with several human diseases, including Alzheimer’s, Huntington’s and Creutzfeldt Jakob’s. Disease-associated amyloid formation is the result of proteins that misfold and aggregate into β sheet-rich fibre polymers. Cellular toxicity is readily associated with amyloidogenesis, although the molecular mechanism of toxicity remains unknown. Recently, a new class of ‘functional’ amyloid fibres was discovered that demonstrates that amyloids can ...

  7. Strength Evaluation of Steel-Nylon Hybrid Fibre Reinforced Concrete

    OpenAIRE

    Maniram Kumar; Er. Ankush Khadwal

    2014-01-01

    When fibres like steel, glass, polypropylene, nylon, carbon, aramid, polyester, jute, etc are mixed with concrete known as fibre reinforced concrete. To overcome the deficiencies of concrete; fibres are added to improve the performance of concrete. In this research hybrid reinforced concrete is made by using steel and nylon 6 fibres. The inclusion of both steel and nylon 6 fibres are used in order to combine the benefits of both fibers; structural improvements provided by stee...

  8. Synchronously pumped picosecond all-fibre Raman laser based on phosphorus-doped silica fibre.

    Science.gov (United States)

    Kobtsev, Sergey; Kukarin, Sergey; Kokhanovskiy, Alexey

    2015-07-13

    Reported for the first time is picosecond-range pulse generation in an all-fibre Raman laser based on P₂O₅-doped silica fibre. Employment of phosphor-silicate fibre made possible single-cascade spectral transformation of pumping pulses at 1084 nm into 270-ps long Raman laser pulses at 1270 nm. The highest observed fraction of the Stokes component radiation at 1270 nm in the total output of the Raman laser amounted to 30%. The identified optimal duration of the input pulses at which the amount of Stokes component radiation in a ~16-m long phosphorus-based Raman fibre converter reaches its maximum was 140-180 ps.

  9. Polarisation effects in twin-core fibre: Application for mode locking in a fibre laser

    Science.gov (United States)

    Lobach, I. A.; Kablukov, S. I.; Podivilov, Evgenii V.; Babin, Sergei A.; Apolonski, A. A.

    2012-09-01

    We report the first measurements of the longitudinal power distribution in a twin-core optical fibre at different input light polarisations. Experimental evidence is presented that, because of the difference in birefringence between the cores, the power in them depends on which core the beam is launched into. Experimental data are interpreted in terms of a modified polarisation model for mode coupling in twin-core fibres which takes into account the birefringence of the cores. In addition, we demonstrate for the first time the use of the polarisation properties of a twincore fibre for mode locking in a fibre laser.

  10. Yb3+-Doped Double-Clad Fibre Laser Based on Fibre Bragg Grating

    Institute of Scientific and Technical Information of China (English)

    范万德; 付圣贵; 张强; 宁鼎; 李丽君; 王志; 袁树忠; 董孝义

    2003-01-01

    A novel Yb3+-doped double-clad fibre laser based on a double-clad fibre Bragg grating is presented. The fibre Bragg grating, as the output mirror, has been formed in Yb3+-doped double-clad fibre with the phase-mask method. When the input pump power is 2.8 W, the maximum laser output power is 570mW, with < 0.2 nm in line-width at the wavelength of 1.058μm, over 40dB signal-to-noise ratio and 24% slope efficiency.

  11. ELASTICITY of SHORT FIBRE REINFORCED POLYAMIDE: MORPHOLOGICAL AND NUMERICAl ANALYSIS OF FIBRE ORIENTATION EFFECTS

    Directory of Open Access Journals (Sweden)

    Francesca Cosmi

    2010-10-01

    Full Text Available The fatigue behaviour of injection moulded short fibre reinforced polymers depends upon fibre orientation, as shown in experiments conducted with notched specimens injected through different injection gates. The different fatigue behaviour is mainly related to the different local elastic properties, as determined by the different fibre orientation patterns, resulting into different strain distributions. In order to quantify the relationship between fibre orientation and elastic constants, the Cell Method was applied to volumes extracted from the specimens, reconstructed by micro-tomography.

  12. 50 CFR 660.719 - Scientific observers.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Scientific observers. 660.719 Section 660... § 660.719 Scientific observers. (a) All fishing vessels with permits issued under this subpart and... accommodate an NMFS certified observer on board to collect scientific data. (b) All vessels with observers...

  13. Dietary fibre fractions in cereal foods measured by a new integrated AOAC method.

    Science.gov (United States)

    Hollmann, Juergen; Themeier, Heinz; Neese, Ursula; Lindhauer, Meinolf G

    2013-10-01

    The reliable determination of soluble, insoluble and total dietary fibre in baked goods and cereal flours is an important issue for research, nutritional labelling and marketing. We compared total dietary fibre (TDF) contents of selected cereal based foods determined by AOAC Method 991.43 and the new AOAC Method 2009.01. Fifteen bread and bakery products were included in the study. Our results showed that TDF values of cereal products determined by AOAC Method 2009.01 were always significantly higher than those determined by AOAC Method 991.43. This was explained by the inclusion of low molecular weight soluble fibre fractions and resistant starch fractions in the TDF measurement by AOAC 2009.01. This documents that nutritional labelling of cereal products poses the challenge how to update TDF data in nutrient databases in a reasonable time with an acceptable expenditure. Copyright © 2013. Published by Elsevier Ltd.

  14. Individual fibre segmentation from 3D X-ray computed tomography for characterising the fibre orientation in unidirectional composite materials

    DEFF Research Database (Denmark)

    Emerson, Monica Jane; Jespersen, Kristine Munk; Dahl, Anders Bjorholm

    2017-01-01

    The aim of this paper is to characterise the fibre orientation in unidirectional fibre reinforced polymers, namely glass and carbon fibre composites. The compression strength of the composite is related to the orientation of the fibres. Thus the orientation is essential when designing materials...... for wind turbine blades. The calculation of the fibre orientation distribution is based on segmenting the individual fibres from volumes that have been acquired through X-ray tomography. The segmentation method presented in this study can accurately extract individual fibres from low contrast X-ray scans...... of composites with high fibre volume fraction. From the individual fibre orientations, it is possible to obtain results which are independent of the scanning quality. The compression strength for both composites is estimated from the average fibre orientations and is found to be of the same order of magnitude...

  15. Scientific Software Component Technology

    Energy Technology Data Exchange (ETDEWEB)

    Kohn, S.; Dykman, N.; Kumfert, G.; Smolinski, B.

    2000-02-16

    We are developing new software component technology for high-performance parallel scientific computing to address issues of complexity, re-use, and interoperability for laboratory software. Component technology enables cross-project code re-use, reduces software development costs, and provides additional simulation capabilities for massively parallel laboratory application codes. The success of our approach will be measured by its impact on DOE mathematical and scientific software efforts. Thus, we are collaborating closely with library developers and application scientists in the Common Component Architecture forum, the Equation Solver Interface forum, and other DOE mathematical software groups to gather requirements, write and adopt a variety of design specifications, and develop demonstration projects to validate our approach. Numerical simulation is essential to the science mission at the laboratory. However, it is becoming increasingly difficult to manage the complexity of modern simulation software. Computational scientists develop complex, three-dimensional, massively parallel, full-physics simulations that require the integration of diverse software packages written by outside development teams. Currently, the integration of a new software package, such as a new linear solver library, can require several months of effort. Current industry component technologies such as CORBA, JavaBeans, and COM have all been used successfully in the business domain to reduce software development costs and increase software quality. However, these existing industry component infrastructures will not scale to support massively parallel applications in science and engineering. In particular, they do not address issues related to high-performance parallel computing on ASCI-class machines, such as fast in-process connections between components, language interoperability for scientific languages such as Fortran, parallel data redistribution between components, and massively

  16. Modern fibre-optic coherent lidars for remote sensing

    Science.gov (United States)

    Hill, Chris

    2015-10-01

    This paper surveys some growth areas in optical sensing that exploit near-IR coherent laser sources and fibreoptic hardware from the telecoms industry. Advances in component availability and performance are promising benefits in several military and commercial applications. Previous work has emphasised Doppler wind speed measurements and wind / turbulence profiling for air safety, with recent sharp increases in numbers of lidar units sold and installed, and with wider recognition that different lidar / radar wavebands can and should complement each other. These advances are also enabling fields such as microDoppler measurement of sub-wavelength vibrations and acoustic waves, including non-lineof- sight acoustic sensing in challenging environments. To shed light on these different applications we review some fundamentals of coherent detection, measurement probe volume, and parameter estimation - starting with familiar similarities and differences between "radar" and "laser radar". The consequences of changing the operating wavelength by three or four orders of magnitude - from millimetric or centimetric radar to a typical fibre-optic lidar working near 1.5 μm - need regular review, partly because of continuing advances in telecoms technology and computing. Modern fibre-optic lidars tend to be less complicated, more reliable, and cheaper than their predecessors; and they more closely obey the textbook principles of easily adjusted and aligned Gaussian beams. The behaviours of noises and signals, and the appropriate processing strategies, are as expected different for the different wavelengths and applications. For example, the effective probe volumes are easily varied (e.g. by translating a fibre facet) through six or eight orders of magnitude; as the average number of contributing scatterers varies, from >1, we should review any assumptions about "many" scatterers and Gaussian statistics. Finally, some much older but still relevant scientific work (by A G Bell, E H

  17. Design Methods for Fibre Reinforced Concrete

    DEFF Research Database (Denmark)

    Stang, Henrik

    1996-01-01

    The present paper describes the outline of a research project on Fibre Reinforced Concrete (FRC) currently being carried out in Denmark under the supervision of Danish Council of Technology, Danish Technical Research Council and Danish Natural Science Research Counsil....

  18. Optical fibres bringing the LHC into focus

    CERN Multimedia

    2003-01-01

    New components are being added to CERN's optical fibre network, which will transport the torrents of data produced by the LHC. 1500 kilometres of cables will be installed in the tunnels and at ground level.

  19. Chinese Market for Fibres and Cables

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    This article presents a summary of Chinese market of optical fibres and cables based on the development of the optical communications industry. Analysis shows that the market will keep growing for sometime in the future.

  20. Flatus emission patterns and fibre intake.

    Science.gov (United States)

    Bolin, T D; Stanton, R A

    1998-01-01

    Knowledge of the normal range of flatus emissions and their relationship to diet, particularly fibre, would be helpful in managing patients who complain of excessive flatus or abdominal distention. Sixty men and 60 women aged between 17 and 67 kept a three-day daily record, including one week-end day, of their flatus emissions, dietary fibre intake and beer consumption. Daily flatus emissions averaged 12.7 (range to 2-53) for men and 7.1 (range 1-32) for women. Fibre intake averaged 28+/-13 g for men and 24+/-3 g for women. Flatus emissions significantly correlated with dietary fibre intake (pflatus emissions and beer intake in men and men recorded more aromatic flatus than women. This study of 120 normal individuals eating their choice of foods provides a basis to judge degrees of abnormality in patients complaining of excessive flatus.

  1. Optical Fibre Pressure Sensors in Medical Applications

    Directory of Open Access Journals (Sweden)

    Sven Poeggel

    2015-07-01

    Full Text Available This article is focused on reviewing the current state-of-the-art of optical fibre pressure sensors for medical applications. Optical fibres have inherent advantages due to their small size, immunity to electromagnetic interferences and their suitability for remote monitoring and multiplexing. The small dimensions of optical fibre-based pressure sensors, together with being lightweight and flexible, mean that they are minimally invasive for many medical applications and, thus, particularly suited to in vivo measurement. This means that the sensor can be placed directly inside a patient, e.g., for urodynamic and cardiovascular assessment. This paper presents an overview of the recent developments in optical fibre-based pressure measurements with particular reference to these application areas.

  2. Central Tracking Detector Based on Scintillating Fibres

    CERN Multimedia

    2002-01-01

    Scintillating fibres form a reasonable compromise for central tracking detectors in terms of price, resolution, response time, occupancy and heat production. \\\\ \\\\ New fluorescents with large Stokes shifts have been produced, capable of working without wavelength shifters. Coherent multibundles have been developed to achieve high packing fractions. Small segments of tracker shell have been assembled and beam tests have confirmed expectations on spatial resolution. An opto-electronic delay line has been designed to delay the track patterns and enable coincidences with a first level trigger. Replacement of the conventional phosphor screen anode with a Si pixel chip is achieved. This tube is called ISPA-tube and has already been operated in beam tests with a scintillating fibres tracker. \\\\ \\\\ The aim of the proposal is to improve hit densities for small diameter fibres by increasing the fraction of trapped light, by reducing absorption and reflection losses, by reflecting light at the free fibre end, and by inc...

  3. Step index fibre using laser interferometer

    Indian Academy of Sciences (India)

    A M Hamed

    2014-03-01

    model is suggested to describe the fringe shift which occurs due to the phase variations of cladded glass fibre introduced between the two plates of the liquid wedge interferometer illuminated with a He–Ne laser. The fringe shift of the phase object which appears in the denominator of the Airy distribution formula of the multiple beam interference is represented in the harmonic term. An experiment is conducted using liquid wedge interferometer where the step index glass fibre of a nearly quadratic thickness variation is introduced between the two plates of the interferometer. The obtained fringe shift shows a good agreement with the proposed quadratic model. The Matlab code is written to plot the interferometer fringes comprising the shift of the step index fibre. Secondly, recognition of elliptical fibres is outlined using tomographic imaging. Finally, results and concluding remarks are given.

  4. Real-time dosimetry with Yb-doped silica optical fibres

    Science.gov (United States)

    Veronese, Ivan; Chiodini, Norberto; Cialdi, Simone; d'Ippolito, Eduardo; Fasoli, Mauro; Gallo, Salvatore; La Torre, Stefano; Mones, Eleonora; Vedda, Anna; Loi, Gianfranco

    2017-05-01

    Over the years, many efforts have been made to develop radiation detectors to handle the complex issues of small field dosimetry and achieve the increasing accuracy, precision and in vivo dose monitoring required by the new advanced treatment modalities. In this context, interest has surged in the development of sensors based on scintillating optical fibres. In this paper, the near-infrared radioluminescence and dosimetric properties of Yb-doped silica optical fibres, coupled with a laboratory prototype based on an avalanche photodiode, were studied by irradiating the fibres with photons and electron beams generated by a Varian Trilogy accelerator. The performance of the system in standard and small field sizes has also been investigated, comparing the output factor, percentage depth dose and off-axis ratio measurements of the prototypal detector with other commercial sensors, including the Exradin W1 scintillator. The results of this study demonstrate that the drawback due to the stem effect in Yb-doped silica optical fibres can be managed in a simple but effective way by optical filtering. The robustness of the system in complex dosimetric scenarios and the accuracy and precision achieved by Yb-doped fibres in relative dose assessments suggest an effective use of the system for real-time in vivo dosimetry applications.

  5. Polarisation control of DFB fibre lasers

    DEFF Research Database (Denmark)

    Varming, Poul; Philipsen, Jacob Lundgreen; Berendt, Martin Ole

    1998-01-01

    The polarisation properties of a distributed feedback (DFB) fibre laser are investigated. It is shown experimentally that the birefringence of the UV induced phase-shift is the dominating effect controlling the polarisation properties of the laser......The polarisation properties of a distributed feedback (DFB) fibre laser are investigated. It is shown experimentally that the birefringence of the UV induced phase-shift is the dominating effect controlling the polarisation properties of the laser...

  6. Dynamic response analysis of DFB fibre lasers

    DEFF Research Database (Denmark)

    Yujun, Qian; Varming, Poul; Povlsen, Jørn Hedegaard

    1998-01-01

    We present a model for relative intensity noise (RIN) in DFB fibre lasers which predicts measured characteristics accurately. Calculation results implies that the RIN decreases rapidly with stronger Bragg grating and higher pump power. We propose here a simplified model based on three spatially...... independent rate equations to describe the dynamic response of erbium doped DFB fibre lasers on pump power fluctuations, using coupled-mode theory to calculate the steady-state hole-burning of the erbium ion inversion...

  7. Design of distributed feedback fibre lasers

    DEFF Research Database (Denmark)

    Lauridsen, Vibeke Claudia; Søndergaard, Thomas; Varming, Poul

    1997-01-01

    A numerical model for erbium fibre lasers with Bragg gratings is presented. The model is used to optimize the location of a discrete phase-shift and the phase-shift magnitude for a distributed phase-shift.......A numerical model for erbium fibre lasers with Bragg gratings is presented. The model is used to optimize the location of a discrete phase-shift and the phase-shift magnitude for a distributed phase-shift....

  8. Energy transfer during the hydroentanglement of fibres

    CSIR Research Space (South Africa)

    Moyo, D

    2012-10-01

    Full Text Available , and the resultant degree of fibre entanglement, determines the tensile strength of the nonwoven fabric as a consequence of the inter-fibre friction. Here, the relationship between hydroentangling energy from the waterjets and the changes it brings about... in the nonwoven fabric strength were studied. In the study, the energies of the waterjets transferred to every fabric sample as a function of the waterjet pressure, machine speed, machine efficiency and the web area weight were quantified, and the resultant...

  9. Fibre-optic sensors in health care

    Science.gov (United States)

    Grazia Mignani, Anna; Baldini, Francesco

    1997-05-01

    Biomedical fibre-optic sensors are attractive for the measurement of physical, chemical and biochemical parameters and for spectral measurements directly performed on the patient. An overview of fibre-optic sensors for in vivo monitoring is given, with particular attention paid to the advantages that these sensors are able to offer in different application fields such as cardiovascular and intensive care, angiology, gastroenterology, ophthalmology, oncology, neurology, dermatology and dentistry.

  10. Angiogenic effect induced by mineral fibres.

    Science.gov (United States)

    Carbonari, Damiano; Campopiano, Antonella; Ramires, Deborah; Strafella, Elisabetta; Staffolani, Sara; Tomasetti, Marco; Curini, Roberta; Valentino, Matteo; Santarelli, Lory; Amati, Monica

    2011-10-09

    Due to the toxic effect of asbestos, other materials with similar chemical-physical characteristics have been introduced to substitute it. We evaluate the angiogenic effect of certain asbestos substitute fibres such as glass fibres (GFs), ceramic fibres (CFs) and wollastonite fibres (WFs) and then compare angiogenic responses to those induced by crocidolite asbestos fibres (AFs). An in vitro model using human endothelial cells in small islands within a culture matrix of fibroblasts (Angio-Kit) was used to evaluate vessel formation. The release of IL-6, sIL-R6, IL-8, VEGF-A and their soluble receptors, sVEGFR-1, sVEGFR-2, was determined in the conditioning medium of Angio-Kit system after fibre treatment. ROS formation and cell viability were evaluated in cultured endothelial cells (HUVEC). To evaluate the involvement of intracellular mechanisms, EGFR signalling, ROS formation and nuclear factor-κB (NFκB) pathway were then inhibited by incubating HUVEC cells with AG1478, NAC and PDTC respectively, and the cytokine and growth factor release was analyzed in the culture medium after 7 days of fibre incubation. Among the mineral fibres tested, WFs markedly induced blood vessel formation which was associated with release of IL-6 and IL-8, VEGF-A and their soluble receptors. ROS production was observed in HUVEC after WFs treatment which was associated with cell cytotoxicity. The EGFR-induced ERK phosphorylation and ROS-mediated NFκB activation were involved in the cytokine and angiogenic factor release. However, only the EGFR activation was able to induce angiogenesis. The WFs are potential angiogenic agents that can induce regenerative cytokine and angiogenic factor production resulting in the formation of new blood vessels.

  11. Photonic crystal fibres in the market

    DEFF Research Database (Denmark)

    Broeng, Jes; Laurila, Marko; Noordegraaf, Danny;

    2011-01-01

    Photonic crystal fibres (PCFs) emerged as a research topic in the mid 1990'ies [1]. Today, 15 years later, these fibres are increasing deployed in various commercial markets. Here, we will address three of these markets; medical imaging, materials processing and sensors. We will describe how...... the PCFs provide radical improvements and illustrate the strong diversity in the evolution of PCFs to serve these different markets....

  12. Force focusing in confined fibres and sheets

    Energy Technology Data Exchange (ETDEWEB)

    Romero, Victor; Cerda, Enrique [Departamento de Fisica, Universidad de Santiago, Av. Ecuador 3493, Santiago (Chile); Witten, T A; Liang Tao [James Franck Institute, University of Chicago, Chicago IL 60637 (United States)], E-mail: t-witten@uchicago.edu

    2008-07-07

    A thin fibre or sheet curled into a circular container has a detached region whose shape and force ratios are independent of material properties and container radius. We compute this shape and compare it with experiments. The discrete forces acting at either end of the detached region have a ratio that depends only on the length of the fibre or sheet relative to the circle radius. We calculate this force ratio in three regimes of circle radius. (fast track communication)

  13. The philosophy of scientific experimentation: a review

    OpenAIRE

    Radder, H.

    2009-01-01

    Practicing and studying automated experimentation may benefit from philosophical reflection on experimental science in general. This paper reviews the relevant literature and discusses central issues in the philosophy of scientific experimentation. The first two sections present brief accounts of the rise of experimental science and of its philosophical study. The next sections discuss three central issues of scientific experimentation: the scientific and philosophical significance of interve...

  14. Economics Of Optical Fibre Transmission Systems

    Science.gov (United States)

    Murray, W. J.

    1983-08-01

    Optical fibre as a telecommunication transmission medium has become one of the most significant developments so far of the digital era. A major contributory factor to the availability of optical fibre transmission systems has been the outstanding progress in the technology of manufacturing high quality glass fibre having relatively low attenuation and broad bandwidths. This and other achievements has enabled manufacturers in the United Kingdom to develop a range of optical fibre cables and transmission equipment for operation over short and long distances at the CCITT recommended digital hierarchical rates of 2, 8, 34 and 140Mbit/s which have been adopted by British Telecom (BT) for modernisation to an all digital transmission network. These optical fibre systems are now becoming increasingly price and performance competitive with conventional technology in many parts of telecommunications networks. In the British Telecom (BT) network the 140Mbit/s optical fibre systems are now economically competitive with equivalent systems on coaxial cable and microwave radio. The economics of 8 and 34Mbit/s systems are not yet sufficiently attractive, compared with 2Mbit/s digital line systems on pair type copper cables, for large scale use in rural and local distribution networks and are presently only justified on cost in and around large cities. As system costs decrease large applications are predicted particularly in support of future high speed data, cable television and visual information services.

  15. Fibre positioning algorithms for the WEAVE spectrograph

    Science.gov (United States)

    Terrett, David L.; Lewis, Ian J.; Dalton, Gavin; Abrams, Don Carlos; Aguerri, J. Alfonso L.; Bonifacio, Piercarlo; Middleton, Kevin; Trager, Scott C.

    2014-07-01

    WEAVE is the next-generation wide-field optical spectroscopy facility for the William Herschel Telescope (WHT) in La Palma, Canary Islands, Spain. It is a multi-object "pick and place" fibre fed spectrograph with more than one thousand fibres, similar in concept to the Australian Astronomical Observatory's 2dF1 instrument with two observing plates, one of which is observing the sky while other is being reconfigured by a robotic fibre positioner. It will be capable of acquiring more than 10000 star or galaxy spectra a night. The WEAVE positioner concept uses two robots working in tandem in order to reconfigure a fully populated field within the expected 1 hour dwell-time for the instrument (a good match between the required exposure times and the limit of validity for a given configuration due to the effects of differential refraction). This presents additional constraints and complications for the software that determines the optimal path from one configuration to the next, particularly given the large number of fibre crossings implied by the 1000 fibre multiplex. This paper describes the algorithms and programming techniques used in the prototype implementations of the field configuration tool and the fibre positioner robot controller developed to support the detailed design of WEAVE.

  16. Criticality and isostaticity in fibre networks

    Science.gov (United States)

    Broedersz, Chase P.; Mao, Xiaoming; Lubensky, Tom C.; Mackintosh, Frederick C.

    2011-12-01

    Disordered fibre networks are the basis of many man-made and natural materials, including structural components of living cells and tissue. The mechanical stability of such networks relies on the bending resistance of the fibres, in contrast to rubbers, which are governed by entropic stretching of polymer segments. Although it is known that fibre networks exhibit collective bending deformations, a fundamental understanding of such deformations and their effects on network mechanics has remained elusive. Here we introduce a lattice-based model of fibrous networks with variable connectivity to elucidate the roles of single-fibre elasticity and network structure. These networks exhibit both a low-connectivity rigidity threshold governed by fibre-bending elasticity and a high-connectivity threshold governed by fibre-stretching elasticity. Whereas the former determines the true onset of network rigidity, we show that the latter exhibits rich zero-temperature critical behaviour, including a crossover between various mechanical regimes along with diverging strain fluctuations and a concomitant diverging correlation length.

  17. Scientific Realism and Primordial Cosmology

    CERN Document Server

    Azhar, Feraz

    2016-01-01

    We discuss scientific realism from the perspective of modern cosmology, especially primordial cosmology: i.e. the cosmological investigation of the very early universe. We first (Section 2) state our allegiance to scientific realism, and discuss what insights about it cosmology might yield, as against "just" supplying scientific claims that philosophers can then evaluate. In particular, we discuss: the idea of laws of cosmology, and limitations on ascertaining the global structure of spacetime. Then we review some of what is now known about the early universe (Section 3): meaning, roughly, from a thousandth of a second after the Big Bang onwards(!). The rest of the paper takes up two issues about primordial cosmology, i.e. the very early universe, where "very early" means, roughly, much earlier (logarithmically) than one second after the Big Bang: say, less than $10^{-11}$ seconds. Both issues illustrate that familiar philosophical threat to scientific realism, the under-determination of theory by data---on a...

  18. Jute fibre reinforced plastic: evaluation of application based properties

    Directory of Open Access Journals (Sweden)

    J. B. Sajin

    2015-01-01

    Full Text Available A fibre extracted from jute is a budding component identified for its potential application in composites. It is imperative to evaluate the parametric and property based features to determine its suitability. In this research study, considering the possible application of the fibre composites, the aptness of these fibres are examined with respect to their physical, mechanical [by layered manufacturing technique(LM] and thermal properties. This study focuses on evaluating the properties and behaviour of raw Jute fibres and NaOH surface treated fibres. Subsequently, the fibres are subjected to thermo-gravimetry tests. The outcome of the thermal analysis clearly indicates that the temperature peak shifts to a higher region in the treated fibre compared to raw fibre. The overall observation strongly emphasize that the physical properties and the thermal behaviour of jute fibre are enhanced after surface treatments which makes it more feasible for its application in composite structures.

  19. Scientific Growth

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    As one of the world's largest grain consumers,food security has always been a major concern for the Chinese nation.China must confront the challenge of feeding a fifth of the world's population with less than 9 percent of the planet's arable land.In 2011,China's grain output recorded growth for the eighth successive year,and total production reached an all-time high of 571million tons.In terms of food security,China's goal is to maintain a self-sufficiency rate of above 95 percent.However,an annual net population growth of 7.39 million and the effective decline of the area of farmland in the country,as a result of urbanization,make achieving such selfsufficiency a serious challenge.Given the heavy burden placed on Chinese agriculture,constantly raising productivity by relying on scientific and technological progress has become a priority for China's agricultural sector.The Ministry of Agriculture,for example,has worked to raise China's annual grain yield per-unit area by 1 percent,on average,over the past decade.Last year,the contributory rate of scientific and technological development to China's agriculture reached 52 percent,surpassing the contribution made by land,labor and other production factors for the first time in history.

  20. Loss of type I fibres in canine pectineus muscle hypotrophy.

    Science.gov (United States)

    Ihemelandu, E C

    1980-01-01

    The total number of fibres, as well as, the number of fibres per fibre type were determined by the indirect fibre-counting method in 32 pectineus muscles from 16 dogs of mixed sexes. Eight pairs of muscles from 8 dogs were judged to be hypotrophic, while the other 8 pairs from another 8 dogs were judged to be normal. The hypotrophic muscles had extremely small muscle fibres, particularly type II fibres. They also had apparently higher percentages of type II muscle fibres within a section. The apparently higher percentage of type II fibres usually observed in the hitsochemical examination of the sections of hypotrophic pectineus muscles did not result from failure of type II fibres to transform to type I fibres. It was rather due to too few type I fibres being present in these muscles as compared to the normal muscles. It was not because there were more type II fibres present in them than in the normal muscles. The fewer type I fibres resulted most likely from loss of already differentiated type I fibres. The loss may be of neural origin.

  1. The effect of fibre content, fibre size and alkali treatment to Charpy impact resistance of Oil Palm fibre reinforced composite material

    Science.gov (United States)

    Fitri, Muhamad; Mahzan, Shahruddin

    2016-11-01

    In this research, the effect of fibre content, fibre size and alkali treatment to the impact resistance of the composite material have been investigated, The composite material employs oil palm fibre as the reinforcement material whereas the matrix used for the composite materials are polypropylene. The Oil Palm fibres are prepared for two conditions: alkali treated fibres and untreated fibres. The fibre sizes are varied in three sizes: 5mm, 7mm and 10mm. During the composite material preparation, the fibre contents also have been varied into 3 different percentages: 5%, 7% and 10%. The statistical approach is used to optimise the variation of specimen determined by using Taguchi method. The results were analyzed also by the Taguchi method and shows that the Oil Palm fibre content is significantly affect the impact resistance of the polymer matrix composite. However, the fibre size is moderately affecting the impact resistance, whereas the fibre treatment is insignificant to the impact resistance of the oil palm fibre reinforced polymer matrix composite.

  2. Crack Growth Monitoring by Embedded Optical Fibre Bragg Grating Sensors: Fibre Reinforced Plastic Crack Growing Detection

    DEFF Research Database (Denmark)

    Pereira, Gilmar Ferreira; Mikkelsen, Lars Pilgaard; McGugan, Malcolm

    2015-01-01

    This article presents a novel method to asses a crack growing/damage event in fibre reinforced plastic, or adhesive using Fibre Bragg Grating (FBG) sensors embedded in a host material. Different features of the crack mechanism that induce a change in the FBG response were identified. Double Canti...

  3. Magnesium Coated Bioresorbable Phosphate Glass Fibres: Investigation of the Interface between Fibre and Polyester Matrices

    Directory of Open Access Journals (Sweden)

    Xiaoling Liu

    2013-01-01

    Full Text Available Bioresorbable phosphate glass fibre reinforced polyester composites have been investigated as replacement for some traditional metallic orthopaedic implants, such as bone fracture fixation plates. However, composites tested revealed loss of the interfacial integrity after immersion within aqueous media which resulted in rapid loss of mechanical properties. Physical modification of fibres to change fibre surface morphology has been shown to be an effective method to improve fibre and matrix adhesion in composites. In this study, biodegradable magnesium which would gradually degrade to Mg2+ in the human body was deposited via magnetron sputtering onto bioresorbable phosphate glass fibres to obtain roughened fibre surfaces. Fibre surface morphology after coating was observed using scanning electron microscope (SEM. The roughness profile and crystalline texture of the coatings were determined via atomic force microscope (AFM and X-ray diffraction (XRD analysis, respectively. The roughness of the coatings was seen to increase from 40±1 nm to 80±1 nm. The mechanical properties (tensile strength and modulus of fibre with coatings decreased with increased magnesium coating thickness.

  4. Hybrid RSOA and fibre raman amplified long reach feeder link for WiMAX-on-fibre

    DEFF Research Database (Denmark)

    Amaya Fernández, Ferney Orlando; Martinez, Javier; Yu, Xianbin;

    2009-01-01

    A distributed fibre Raman amplified long reach optical access feeder link using a reflective semiconductor optical amplifier in the remote base station is experimentally demonstrated for supporting WiMAXover- fibre transmission. The measured values for the error vector magnitude for quadrature ph...

  5. Estimation of Single-fibre Tensile Properties from the Bundle Tensile Curve of Polyester Fibres

    Institute of Scientific and Technical Information of China (English)

    于伟东

    2004-01-01

    Fibre bundle tensile curves can be used to characterise fibre processing properties and end-use performance directly and to predict single-fibre properties in theory. In this paper, the tensile behaviour of polyester fibre-bundles has been analysed in characteristic values and diagramming. The characteristic distributions which include the symmetry distribution on right part, SRBS′ (e), on left part, SLBS′(e) and the curve on base-line modification, MBS′ (e),based on the modulus distribution, BS′ (e), as well as the frequency density function of broken fibres, B′ (e), have been derived from the tail of bundle tensile curves. The theoretical and measured results show that the most important curves are MBS′ ( e ) and B′ ( e ) and can be used to estimate the breaking-extension distribution of single fibres. Especially for MBS′(e), the modulus distribution can accurately characterize single-fibre tensile properties and is no limitation as the calculation of B′(e) because the bundle specific stress Y(e) of no fibre breaking at extension e should be found at first.

  6. Strength Evaluation of Steel-Nylon Hybrid Fibre Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Maniram Kumar

    2014-07-01

    Full Text Available When fibres like steel, glass, polypropylene, nylon, carbon, aramid, polyester, jute, etc are mixed with concrete known as fibre reinforced concrete. To overcome the deficiencies of concrete; fibres are added to improve the performance of concrete. In this research hybrid reinforced concrete is made by using steel and nylon 6 fibres. The inclusion of both steel and nylon 6 fibres are used in order to combine the benefits of both fibers; structural improvements provided by steel fibers and the resistance to plastic shrinkage improvements provided by nylon fibers. So the aim of this project is to investigate the mechanical properties (compressive strength, flexure strength and split tensile strength of hybrid fiber reinforced concrete under compression, flexure & tension. The total volume of fibre was taken 0.75 % of total volume of concrete. In this experimental work, four different concrete mix proportions were casted with fibres and one mix without fibres. Four different mix combinations of steel- nylon 6 fibres were 100-00%, 75-25%, 50-50% and 25-75%. Superplasticizer was used in all mixes to make concrete more workable. The results shown that compressive, split tensile and flexural strength of hybrid fibre reinforced concrete increase by increasing quantity of steel and nylon 6 fibres. The increase in compressive and tensile strength due to incorporation of steel fibre is greater than that of using nylon fibre. For the nylon 6 fibres, adding more fibres into the concrete has a limited improvement on splitting tensile strength. Inclusion of nylon 6 fibres along with steel fibres results in considerable improvement in flexural strength as compared to solo steel fibre.

  7. Fibre Bragg Grating and Long Period Grating Sensors in Polymer Optical Fibres

    DEFF Research Database (Denmark)

    Bundalo, Ivan-Lazar

    of applications and pushing the limits. The first part of the work focuses on the fabrication of FBGs in polymer optical fibres. FBGs are a periodic perturbation of the refractive index of the optical fibre core which act as a wavelength specific reflector. The fibres used are made of Polymethyl methacrylate......, strain duration, increasing number of cycles, and it decreases with relaxation duration. For strains up to 0.9%, fast relaxing ΔΛfast range takes no less than 65% of the total strain range. Increase in ΔΛslow due to cyclic straining and relaxing seems to reach an equilibrium value, suggesting that ΔΛslow...... which translates the outside pressure into strain on the fibre. The transducer consisted of a 3Dprinted skeleton through which the fibre is pulled. A latex material is then wrapped around it and all the holes were sealed in order to prevent the air from leaking out. The pod transducer was tested...

  8. Study of the behaviour of the fibre Bragg grating fabricated with cladding mode suppression fibre

    Institute of Scientific and Technical Information of China (English)

    徐新华; 吕昌贵; 崔一平

    2003-01-01

    One effective method for suppression of coupling from guided optical modes into cladding modes in an optical fibre Bragg grating is to use cladding mode suppression fibre.In this specially engineered fibre,the grating is written into the core and the inner cladding,both of which are photosensitive.A theory is presented in this paper to analyse the spectral characteristics of this kind of gratings.A fibre Bragg grating was experimentally fabricated with this kind of photosensitive fibre(PS-RMS-50 from StockerYale).It is shown both theoretically and experimentally that such gratings exhibit strong suppression of the coupling between core mode and cladding mode.The experimental result is in good agreement with the theoretical analysis.

  9. Hemp fibres: Enzymatic effect of microbial processing on fibre bundle structure

    DEFF Research Database (Denmark)

    Thygesen, Anders; Liu, Ming; Meyer, Anne S.

    2013-01-01

    The effects of microbial pretreatment on hemp fibres were evaluated after microbial retting using the white rot fungi Ceriporiopsis subvermispora and Phlebia radiata Cel 26 and water retting. Based on chemical composition, P. radiata Cel 26 showed the highest selectivity for pectin and lignin...... degradation and lowest cellulose loss (14%) resulting in the highest cellulose content (78.4%) for the treated hemp fibres. The pectin and lignin removal after treatment with P. radiata Cel 26 were of the order 82% and 50%, respectively. Aligned epoxy-matrix composites were made from hemp fibres defibrated...... hemp fibres were badly impregnated due to porosity caused by surface impurities such as epidermis and other pectin rich plant cells. The pectin and lignin mainly located in the outer part of the fibres were assumed to be extracted and degraded by pectinase and peroxidase enzymes produced by the fungi....

  10. Polarisation maintaining fibre with pure silica core and two depressed claddings for fibre optic gyroscope

    Science.gov (United States)

    Kurbatov, A. M.; Kurbatov, R. A.; Voloshin, V. V.; Vorob'ev, I. L.; Kolosovsky, A. O.

    2016-12-01

    Polarisation maintaining (PM) fibre is described with pure silica core and two depressed claddings for fibre optic gyro (FOG) sensing coil. Detailed mathematical simulation is presented by supermodes method, which is extremely necessary for such fibre. Simulation is fulfilled by frequency domain finite difference method (FDFDM), taking into account all details of realistic index profile with stress applying parts, while the leakage/bend loss occur in the region with complex index, surrounding the fibre. Cutoff and small bend loss are theoretically predicted and experimentally measured with excellent agreement between theory and experiment. Polarisation maintaining ability is measured in the form of conventional h-parameter (7.1·10-6 1/m) for 90-μm diameter fibre with birefringence value only 3.9·10-4.

  11. DESIGN NOTE: Surface microscopy and fibre characterization using a multimode-fibre reflectance microscope

    Science.gov (United States)

    Lukins, P. B.; Rehman, S.; Stevens, G. B.

    2000-04-01

    A remarkably simple scanning infrared surface-reflectance microscope based on a multimode-fibre-coupled diode laser together with straightforward electronics and scanning stage is described. The design does not require alignment and completely avoids the use of objectives, beamsplitters and other optics normally associated with such microscopes. The axial response, resolution and imaging properties for non-interferometric operation are characterized. A geometric model for the transmission of such a microscope using an idealized step/graded-index multimode fibre is presented. This model is used to explain the axial response of the microscope. Finally, a new method for determination of the numerical aperture and index-grading parameter of multimode fibres is proposed. This method is based on the geometric model together with axial-response measurements using the microscope in such a way that the fibre probe is the actual test fibre.

  12. Mechanical processing of bast fibres: The occurrence of damage and its effect on fibre structure

    DEFF Research Database (Denmark)

    Hänninen, Tuomas; Thygesen, Anders; Mehmood, Shahid

    2012-01-01

    Currently, separation processes used for natural fibres for composite reinforcing textiles cause a significant amount of damage to the fibres. Microscopic analysis showed that industrially processed flax (Linum usitassimium L.) fibres contained significantly more defects than green or retted ones...... and that further mechanical processing did not significantly increase the amount of defects. In this study it has been shown, by analysing the degree of polymerisation of cell wall components indirectly by viscosity measurements, that mechanically induced defects do not significantly cleave the cell wall polymers....... Acid hydrolysis, however, induced more degradation of the cell wall polymers in fibres having a greater degree of damage, indicating that that defects are more susceptible to certain chemical reactions and which in turn might cause problems for example, during chemical modification of fibres due...

  13. Effects of Polarization-Maintaining Fibre Degrading on Precision of Fibre Optic Gyroscopes in Radiation Environment

    Institute of Scientific and Technical Information of China (English)

    XIAO Wen; LIU De-Wen; LIU Yang; YI Xiao-Su; CONG Lin

    2008-01-01

    @@ In the space environment, the precision of fibre optic gyroscopes (FOGs) degrades because of space radiation.Photonic components of FOGs axe affected by radiation, especially the polaxization-maintaining (PM) fibre coil.In relation to the space radiation environment characteristic, we have carried out a series of radiation experiments on a PM fibre coil with 60Co radiation source at different dose rates. Based on the experimental results, the formula between the PM-fibre loss and radiation dose rata is built, and the relation between the precision of FOG and radiation dose is obtained accordingly. The results strongly show that the precision of our FOG degrades owing to the attenuation of the polarization-maintaining fibre, which provides theoretical foundation for the radiation-resistant design of the FOG.

  14. Voronoi cells, fractal dimensions and fibre composites.

    Science.gov (United States)

    Summerscales, J.; Guild, F. J.; Pearce, N. R. L.; Russell, P. M.

    2001-02-01

    The use of fibre-reinforced polymer matrix composite materials is growing at a faster rate than the gross domestic product (GDP) in many countries. An improved understanding of their processing and mechanical behaviour would extend the potential applications of these materials. For unidirectional composites, it is predicted that localized absence of fibres is related to longitudinal compression failure. The use of woven reinforcements permits more effective manufacture than for unidirectional fibres. It has been demonstrated experimentally that compression strengths of woven composites are reduced when fibres are clustered. Summerscales predicted that clustering of fibres would increase the permeability of the reinforcement and hence expedite the processing of these materials. Commercial fabrics are available which employ this concept using flow-enhancing bound tows. The net effect of clustering fibres is to enhance processability whilst reducing the mechanical properties. The effects reported above were qualitative correlations. To improve the design tools for reinforcement fabrics we have sought to quantify the changes in the micro/meso-structure of woven reinforcement fabrics. Gross differences in the appearance of laminate sections are apparent for different weave styles. The use of automated image analysis is essential for the quantification of subtle changes in fabric architecture. This paper considers Voronoi tessellation and fractal dimensions for the quantification of the microstructures of woven fibre-reinforced composites. It reviews our studies in the last decade of the process-property-structure relationships for commercial and experimental fabric reinforcements in an attempt to resolve the processing vs. properties dilemma. A new flow-enhancement concept has been developed which has a reduced impact on laminate mechanical properties.

  15. Latest developments in silica fibre luminescence dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, D. A.; Abdul S, S. F.; Jafari, S. M.; Alanazi, A. [University of Surrey, Department of Physics, GU2 7XH Guildford, Surrey (United Kingdom); Amouzad M, G. [University of Malaya, Faculty of Engineering, Department of Electrical Engineering, Integrated Lightwave Research Group, 50603 Kuala Lumpur (Malaysia); Addul R, H. A.; Mizanur R, A. K. M.; Zubair, H. T.; Begum, M.; Yusoff, Z.; Omar, N. Y. M. [Multimedia University, Faculty of Engineering, 2010 Cyberjaya, Selangor (Malaysia); Maah, M. J. [University of Malaya, Department of Chemistry, 50603 Kuala Lumpur (Malaysia); Collin, S. [National Physical Laboratory, Hampton Road, Teddington, TW11 OLW Middlesex (United Kingdom); Mat-Sharif, K. A.; Muhd-Yassin, S. Z.; Zulkifli, M. I., E-mail: d.a.bradley@surrey.ac.uk [Telekom Malaysia Research and Development Sdn Bhd., 63000 Cyberjaya, Selangor (Malaysia)

    2015-10-15

    Full text: Using tailor made sub-mm diameter doped-silica fibres, we are carrying out luminescence dosimetry studies for a range of situations, including thermoluminescence (Tl)investigations on a liquid alpha source formed of {sup 223}RaCl (the basis of the Bayer Health care product Xofigo), the Tl response to a 62 MeV proton source and Tl response to irradiation from an {sup 241}Am-Be neutron source. In regard to the former, in accord with the intrinsic high linear energy transfer (Let) and short path length (<100 um) of the α-particles in calcified tissue, the product is in part intended as a bone-seeking radionuclide for treatment of metastatic cancer, offering high specificity and efficacy. The Tl yield of Ge-doped SiO{sub 2} fibres has been investigated including for photonic crystal fibre un collapsed, flat fibres and single mode fibres, these systems offering many advantages over conventional passive dosimetry types. In particular, one can mention comparable and even superior sensitivity, an effective atomic number Z{sub eff} of the silica dosimetric material close to that of bone, and the glassy nature of the fibres offering the additional advantage of being able to place such dosimeters directly into liquid environments. Finally we review the use of our tailor made fibres for on-line radioluminescence measurements of radiotherapy beams. The outcome from these various lines of research is expected to inform development of doped fiber radiation dosimeters of versatile utility, ranging from clinical applications through to industrial studies and environmental evaluations. (Author)

  16. Microanalytical investigation of fibre-reinforced ceramic materials

    Energy Technology Data Exchange (ETDEWEB)

    Meier, B.; Grathwohl, G.

    1989-03-01

    Microanalytical investigations have been made on samples of ceramic fibres (SiC fibres, (Nicalon) C fibre coated with TiN) and fibre-reinforced ceramics (SiC-and glass-matrices). High resolution Auger electron spectroscopy (HRAES), electron probe microanalysis (EPMA) and scanning electron microscopy were employed for these examinations. Analysis was best performed with HRAES on account of its lateral and depth resolution. Some of the problems involved in this technique are discussed e.g. electron beam effects. AES depth profiles of ceramic fibres are reported and compared with the surface analysis of fibres in the composites after being broken in situ.

  17. Influence of the Testing Gage Length on the Strength, Young's Modulus and Weibull Modulus of Carbon Fibres and Glass Fibres

    Directory of Open Access Journals (Sweden)

    Luiz Claudio Pardini

    2002-10-01

    Full Text Available Carbon fibres and glass fibres are reinforcements for advanced composites and the fiber strength is the most influential factor on the strength of the composites. They are essentially brittle and fail with very little reduction in cross section. Composites made with these fibres are characterized by a high strength/density ratio and their properties are intrisically related to their microstructure, i.e., amount and orientation of the fibres, surface treatment, among other factors. Processing parameters have an important role in the fibre mechanical behaviour (strength and modulus. Cracks, voids and impurities in the case of glass fibres and fibrillar misalignments in the case of carbon fibres are created during processing. Such inhomogeneities give rise to an appreciable scatter in properties. The most used statistical tool that deals with this characteristic variability in properties is the Weibull distribution. The present work investigates the influence of the testing gage length on the strength, Young's modulus and Weibull modulus of carbon fibres and glass fibres. The Young's modulus is calculated by two methods: (i ASTM D 3379M, and (ii interaction between testing equipment/specimen The first method resulted in a Young modulus of 183 GPa for carbon fibre, and 76 GPa for glass fibre. The second method gave a Young modulus of 250 GPa for carbon fibre and 50 GPa for glass fibre. These differences revelead differences on how the interaction specimen/testing machine can interfere in the Young modulus calculations. Weibull modulus can be a tool to evaluate the fibre's homogeneity in terms of properties and it is a good quality control parameter during processing. In the range of specimen gage length tested the Weibull modulus for carbon fibre is ~ 3.30 and for glass fibres is ~ 5.65, which indicates that for the batch of fibres tested, the glass fibre is more uniform in properties.

  18. GLUT4 expression at the plasma membrane is related to fibre volume in human skeletal muscle fibres

    DEFF Research Database (Denmark)

    Gaster, M; Vach, W; Beck-Nielsen, H

    2002-01-01

    In this study we examined the relationship between GLUT4 expression at the plasma membrane and muscle fibre size in fibre-typed human muscle fibres by immunocytochemistry and morphometry in order to gain further insight into the regulation of GLUT4 expression. At the site of the plasma membrane......, GLUT4 was more abundantly expressed in slow as compared to fast fibres at the same fibre diameter (p diabetic and obese was reduced...... compared to control subjects at the same diameter (p diabetic subjects expressed a fibre-volume-dependent GLUT4 expression (p diabetic p = 0.06). Our results show that increasing...

  19. Plant fibre composites - porosity and stiffness

    DEFF Research Database (Denmark)

    Madsen, Bo; Thygesen, Anders; Lilholt, Hans

    2009-01-01

    Plant fibre composites contain typically a relatively large amount of porosity which influences their performance. A model, based on a modified rule of mixtures, is presented to include the influence of porosity on the composite stiffness. The model integrates the volumetric composition of the co......Plant fibre composites contain typically a relatively large amount of porosity which influences their performance. A model, based on a modified rule of mixtures, is presented to include the influence of porosity on the composite stiffness. The model integrates the volumetric composition...... of the composites with their mechanical properties. The fibre weight fraction is used as an independent parameter to calculate the complete volumetric composition. A maximum obtainable stiffness of the composites is calculated at a certain transition fibre weight fraction, which is characterised by a best possible...... combination of high fibre volume fraction and low porosity. The model is validated with experimental data from the literature on several types of composites. A stiffness diagram is presented to demonstrate that the calculations can be used for tailoring and design of composites with a given profile...

  20. A large Scintillating Fibre Tracker for LHCb

    Science.gov (United States)

    Greim, R.

    2017-02-01

    The LHCb experiment will be upgraded during LHC Long Shutdown 2 to be able to record data at a higher instantaneous luminosity. The readout rate is currently limited to 1 MHz by the Level 1 trigger. In order to achieve the target integrated luminosity of 50 fb-1 during LHC Run 3, all subdetectors have to be read out by a 40 MHz trigger-less readout system. Especially, the current tracking detectors downstream of the LHCb dipole magnet suffer from large detector dead times and a small granularity in the Outer Tracker, which consists of proportional straw tubes. Therefore, the Downstream Tracker will be replaced by a Scintillating Fibre Tracker with Silicon Photomultiplier readout. The total sensitive area of 340 m2 is made up of 2.5 m long fibre mats consisting of six staggered layers of 250 μm thin scintillating fibres. The scintillation light created by the charged particles traversing the fibre mats is transported to the fibre ends via total internal reflection and detected by state-of-the-art multi-channel SiPM arrays. This paper presents the detector concept, design, challenges, custom-made readout chips, as well as laboratory and beam test results.

  1. Influence of Slip on the Plateau-Rayleigh Instability on a Fibre

    CERN Document Server

    Haefner, Sabrina; Baümchen, Oliver; Salez, Thomas; Peters, Robert; McGraw, Joshua D; Jacobs, Karin; Raphaël, Elie; Dalnoki-Veress, Kari

    2015-01-01

    Glistening pearls of water on a spider's web, or the breakup of a cylindrical jet of water into droplets, are familiar manifestations of the Plateau-Rayleigh instability (PRI). By evolving into droplets, the surface area of the liquid, and consequently the surface energy, are reduced. This instability also acts for a liquid film coating a solid fibre, though the flow boundary condition at the solid-liquid interface provides additional complexity to the system. While the breakup of a homogenous film into droplets on a fibre may be a nuisance in coating technologies of e.g. wires and optical fibres, this fundamental instability turns out to be very useful: take for example water collection through fog harvesting, a biomimetic approach that is perfected in nature by the spider's web. Here, we take advantage of the PRI on a fibre to gain physical insight into the solid-liquid boundary condition. Indeed, understanding the break-down of the no-slip boundary condition is of major interest to the scientific and indus...

  2. Mechanical Property Analysis on Sandwich Structured Hybrid Composite Made from Natural Fibre, Glass Fibre and Ceramic Fibre Wool Reinforced with Epoxy Resin

    Science.gov (United States)

    Bharat, K. R.; Abhishek, S.; Palanikumar, K.

    2017-06-01

    Natural fibre composites find wide range of applications and usage in the automobile and manufacturing industries. They find lack in desired properties, which are required for present applications. In current scenario, many developments in composite materials involve the synthesis of Hybrid composite materials to overcome some of the lacking properties. In this present investigation, two sandwich structured hybrid composite materials have been made by reinforcing Aloe Vera-Ceramic Fibre Wool-Glass fibre with Epoxy resin matrix and Sisal fibre-Ceramic Fibre Wool-Glass fibre with Epoxy resin matrix and its mechanical properties such as Tensile, Flexural and Impact are tested and analyzed. The test results from the two samples are compared and the results show that sisal fibre reinforced hybrid composite has better mechanical properties than aloe vera reinforced hybrid composite.

  3. Electrospinning versus fibre production methods: from specifics to technological convergence.

    Science.gov (United States)

    Luo, C J; Stoyanov, Simeon D; Stride, E; Pelan, E; Edirisinghe, M

    2012-07-07

    fibre processing. Thus, this review combines interdisciplinary knowledge from the academia and industry to facilitate technological convergence and offers insight for upscaling electrospinning and nanofibre production. It will examine advances in electrospinning within a framework of large-scale fibre production as well as alternative nanofibre forming methods, providing a comprehensive comparison of conventional and contemporary fibre forming technologies. This study intends to stimulate interest in addressing the issue of scale-up alongside novel developments and applications in nanofibre research.

  4. Fatigue processes in thermoplastic fibres; Les mecanismes de fatigue dans les fibres thermoplastiques

    Energy Technology Data Exchange (ETDEWEB)

    Herrera Ramirez, J.M.

    2004-09-15

    The present study examines and compares the behaviour of the two types of PA66 fibres and two types of PET fibres under fatigue loading up to failure, and the correlation between the fibres (nano)structures and their structural heterogeneities, with fatigue lifetimes. Several techniques have been used to analyze the materials, such as scanning electron microscopy (SEM), microanalysis (EDS), differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and micro-Raman spectroscopy. A meticulous analysis by scanning electron microscopy of the fracture morphology of fibres broken in tension and in fatigue, as well as a study of the fatigue life, were undertaken. The fatigue process occurs when the cyclic load amplitude is sufficiently large, however a condition for fatigue failure is that the minimum load each cycle must be lower than a threshold stress level. Failure under fatigue conditions leads to distinctive fracture morphologies which are very different from those seen after tensile or creep failure and this allows easy identification of the fatigue process. The fibres have been analyzed in the as received state and after fatigue failure in order to observe the microstructural changes resulting from the fatigue loading. The results will be compared with those obtained for fibres loaded under conditions where the fatigue process was hindered. The role of the microstructure of the fibres in determining fatigue will be discussed in this work and the possibility of improving their resistance to fatigue or eliminating the fatigue process will be discussed. (author)

  5. Study of injection moulded long glass fibre-reinforced polypropylene and the effect on the fibre length and orientation distribution

    Science.gov (United States)

    Parveeen, B.; Caton-Rose, P.; Costa, F.; Jin, X.; Hine, P.

    2014-05-01

    Long glass fibre (LGF) composites are extensively used in manufacturing to produce components with enhanced mechanical properties. Long fibres with length 12 to 25mm are added to a thermoplastic matrix. However severe fibre breakage can occur in the injection moulding process resulting in shorter fibre length distribution (FLD). The majority of this breakage occurs due to the melt experiencing extreme shear stress during the preparation and injection stage. Care should be taken to ensure that the longer fibres make it through the injection moulding process without their length being significantly degraded. This study is based on commercial 12 mm long glass-fibre reinforced polypropylene (PP) and short glass fibre Nylon. Due to the semi-flexiable behaviour of long glass fibres, the fibre orientation distribution (FOD) will differ from the orientation distribution of short glass fibre in an injection molded part. In order to investigate the effect the change in fibre length has on the fibre orientation distribution or vice versa, FOD data was measured using the 2D section image analyser. The overall purpose of the research is to show how the orientation distribution chnages in an injection moulded centre gated disc and end gated plaque geometry and to compare this data against fibre orientation predictions obtained from Autodesk Moldflow Simulation Insight.

  6. Pulse Compression And Raman Amplification In Optical Fibres

    Science.gov (United States)

    Byron, Kevin C.

    1988-06-01

    Experimental and theoretical investigations on Raman amplification in fibres have been carried out and simultaneous amplification and pulse compression observed. With a fibre design optimised for amplification high gain may be obtained at practical pump power levels.

  7. Mechanical Properties of Man-Made Mineral glass fibres

    DEFF Research Database (Denmark)

    Lund, Majbritt Deichgræber; Yue, Yuanzheng

    In nature basaltic volcanic glass fibres are know from Hawaii as Pele's hair, formed by droplets of lava thrown into the air during volcanic eruption. The concept of glass fibre formation by an air stream dragging fibres from drops of melt is copied in industry to form basaltic glass wool fibres......; man-made mineral glass fibres. The basaltic melt is prevented from crystallizing due to the high cooling rate, forming the mineral glass wool fibres. Basaltic mineral wool fibres are of high interest in industry due to their good chemical durability and excellent heat and sound insulation properties...... of the information gained from the mechanical tests, fracture characteristics of individual glass fibres are imaged by scanning electron microscopy. The fracture surfaces showed to fall in three groups; 1) surfaces including fracture mirror, mist and hackle, 2) bend fracture surfaces and 3) surfaces including pores...

  8. Fibre-Optic Strain Measurement For Structural Integrity Monitoring

    NARCIS (Netherlands)

    Bruinsma, A.J.A.; Zuylen, P. van; Lamberts, C.W.; Krijger, A.J.T. de

    1984-01-01

    A method is demonstrated for monitoring the structural integrity of large structures, using an optical fibre. The strain distribution along the structure is monitored by measuring the attentuation of light along the length of the fibre.

  9. Microstructure and Mechanical Properties of Aligned Natural Fibre Composites

    DEFF Research Database (Denmark)

    Rask, Morten

    properties (stiffness-to-density ratio). The perspective of using natural fibres is to have a sustainable, biodegradable, CO2-neutral alternative to glass fibres. However, so far, it has not been possible to take full advantage of the natural fibre properties when using them for composite applications......Recently, there has been a great interest in developing and maturing natural fibre composites for structural applications. Natural fibres derived from plants such as flax and hemp have the potential to compete with traditional glass fibres as reinforcements in polymer matrices, due to good specific....... Several challenges have to be addressed and solved, many of which pertain to the fact that the fibres are sourced from a natural resource: 1) Inconsistent properties, depending on plant species, growth and harvest conditions, and fibre extraction techniques. 2) Strength values of composites are lower than...

  10. On the behaviour of gelled fibre suspensions in steady shear

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, Bettina [Unilever Corporate Research, Bedford (United Kingdom); University of Nottingham, Division of Food Sciences, Loughborough (United Kingdom); White, Duncan; Melrose, John R.; Frith, William J. [Unilever Corporate Research, Bedford (United Kingdom)

    2007-03-15

    The shear rheological properties of suspensions of gelled agar fibres in a low viscosity Newtonian matrix fluid were investigated. Two classes of fibres, low aspect ratio fibres and high aspect ratio fibres with an aspect ratio of the order of 10 and 100 respectively were included in the investigations. For all fibre phase volumes investigated, from as low as 0.01 upwards, the flow curves are characterised by an apparent yield stress followed by shear-thinning which was independent of the fibre aspect ratio. Based on our analysis of the flow curves, we conclude that the high aspect ratio fibres behave like flexible threads in contrast to the low aspect ratio fibres whose high shear relative viscosity is successfully described by a relation for long rigid rods. These findings are supported by flow visualisation using an optical shearing stage coupled to a light microscope. (orig.)

  11. The in vivo biological activity of ceramic fibres.

    Science.gov (United States)

    Brown, R C; Hoskins, J A; Glass, L R

    1995-10-01

    The well-known health effects following exposure to amphibole asbestos have led to some concern about the potential for other fibrous materials to cause similar diseases. This paper presents a summary of some of the inhalation experiments conducted with ceramic fibres in both rats and hamsters at the Research and Consulting Company, Geneva. One ceramic fibre (designated RCF1) was tested in rats at four exposure levels, this fibre was also tested in hamsters. Three other fibres were only tested in rats at the highest level--30 mg m-3. The increased incidence of tumours in these experiments has been contrasted with the negative results obtained with glass or mineral wools. However, there is evidence that the ceramic fibres were longer than the glass fibres and that long ceramic fibres were retained in lung tissue to a greater extent. This is sufficient to explain the results without recourse to explanations based on chemical differences between fibres.

  12. Rare Earth Doped Optical Fibre From Oxide Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Minati Chatterjee; Aharon Gedanken; Renata Reisfeld; Ranjan Sen; Mrinmay Pal; Milan Naskar; Mukul Paul; Shyamal Bhadra; Kamal Dasgupta; Dibyendu Ganguli; Tarun Bandyopadhyay

    2003-01-01

    Rare earth (RE) doped optical fibres were fabricated by using RE oxides coated silica nanoparticles. The fibre properties are comparable to those prepared by conventional techniques. The process offers better control over RE incorporation and homogeneity in the preform.

  13. Special Polymer Optical Fibres and Devices for Photonic Applications

    Institute of Scientific and Technical Information of China (English)

    Gang-Ding Peng

    2003-01-01

    Remarkable progresses have been made in developing special polymer optical fibres and devices for photonic applications in recent years. This presentation will mainly report on the development of electro-optic, photosensitive and photorefractive polymer optical fibres and related devices.

  14. Manufacturing Titanium Metal Matrix Composites by Consolidating Matrix Coated Fibres

    Institute of Scientific and Technical Information of China (English)

    Hua-Xin PENG

    2005-01-01

    Titanium metal matrix composites (TiMMCs) reinforced by continuous silicon carbide fibres are being developed for aerospace applications. TiMMCs manufactured by the consolidation of matrix-coated fibre (MCF) method offer optimum properties because of the resulting uniform fibre distribution, minimum fibre damage and fibre volume fraction control. In this paper, the consolidation of Ti-6Al-4V matrix-coated SiC fibres during vacuum hot pressing has been investigated. Experiments were carried out on multi-ply MCFs under vacuum hot pressing (VHP). In contrast to most of existing studies, the fibre arrangement has been carefully controlled either in square or hexagonal arraysthroughout the consolidated sample. This has enabled the dynamic consolidation behaviour of MCFs to be demonstrated by eliminating the fibre re-arrangement during the VHP process. The microstructural evolution of the matrix coating was reported and the deformation mechanisms involved were discussed.

  15. Turbulence hierarchy in a random fibre laser

    Science.gov (United States)

    González, Iván R. Roa; Lima, Bismarck C.; Pincheira, Pablo I. R.; Brum, Arthur A.; Macêdo, Antônio M. S.; Vasconcelos, Giovani L.; de S. Menezes, Leonardo; Raposo, Ernesto P.; Gomes, Anderson S. L.; Kashyap, Raman

    2017-05-01

    Turbulence is a challenging feature common to a wide range of complex phenomena. Random fibre lasers are a special class of lasers in which the feedback arises from multiple scattering in a one-dimensional disordered cavity-less medium. Here we report on statistical signatures of turbulence in the distribution of intensity fluctuations in a continuous-wave-pumped erbium-based random fibre laser, with random Bragg grating scatterers. The distribution of intensity fluctuations in an extensive data set exhibits three qualitatively distinct behaviours: a Gaussian regime below threshold, a mixture of two distributions with exponentially decaying tails near the threshold and a mixture of distributions with stretched-exponential tails above threshold. All distributions are well described by a hierarchical stochastic model that incorporates Kolmogorov's theory of turbulence, which includes energy cascade and the intermittence phenomenon. Our findings have implications for explaining the remarkably challenging turbulent behaviour in photonics, using a random fibre laser as the experimental platform.

  16. TAIPAN fibre feed and spectrograph: engineering overview

    Science.gov (United States)

    Staszak, Nicholas F.; Lawrence, Jon; Zhelem, Ross; Content, Robert; Churilov, Vladimir; Case, Scott; Brown, Rebecca; Hopkins, Andrew M.; Kuehn, Kyler; Pai, Naveen; Klauser, Urs; Nichani, Vijay; Waller, Lew

    2016-07-01

    TAIPAN will conduct a stellar and galaxy survey of the Southern sky. The TAIPAN positioner is being developed as a prototype for the MANIFEST instrument on the GMT. The TAIPAN Spectrograph is an AAO designed all-refractive 2-arm design that delivers a spectral resolution of R>2000 over the wavelength range 370-870 nm. It is fed by a custom fibre cable from the TAIPAN Starbugs positioner. The design for TAIPAN incorporates 150 optical fibres (with an upgrade path to 300). Presented is an engineering overview of the UKST Fibre Cable design used to support Starbugs, the custom slit design, and the overall design and build plan for the TAIPAN Spectrograph.

  17. Development of SERS active fibre sensors

    CERN Document Server

    Polwart, E

    2002-01-01

    Surface-enhanced Raman scattering (SERS) is sensitive and selective and when coupled with fibre-optics could potentially produce an effective chemical sensing system. This thesis concerns the development of a single-fibre-based sensor, with an integral SERS-active substrate. A number of different methods for the manufacture of SERS-active surfaces on glass substrates were investigated and compared. The immobilisation of metal nanoparticles on glass functionalised with (3-aminopropyl)trimethoxysilane emerged as a suitable approach for the production of sensors. Substrates prepared by this approach were characterised using UV-visible spectroscopy, electron microscopy and Raman mapping. It was found that exposure of substrates to laser radiation led to a decrease in the signal recorded from adsorbed analytes. This speed of the decrease was shown to depend on the analyte, and the exciting wavelength and power. SERS-active fibre sensors were produced by immobilisation of silver nanoparticles at the distal end of a...

  18. Optical fibre cantilever sensor for biological application

    Science.gov (United States)

    Li, J.; Zhou, Y. X.; Patterson, G.; Shu, W. M.; Maier, R. R. J.; Fowler, R.; Hand, D. P.; MacPherson, W. N.

    2014-05-01

    Micro-cantilever sensors have shown great promise in a wide range of application are as including chemical and biological sensing. However, many of these devices are based upon a sensor `chip' that requires careful alignment between the cantilever and the read-out system, which can be challenging. Furthermore, optical interrogation typically involves a bulky free-space system. Optical fibre addressed cantilevers have been reported previously in the literature and in this paper we propose techniques to design and fabricate polymer micro-cantilevers for attachment onto the end of standard single mode fibres using laser machining. Low-cost optical sources and a fibre coupled spectrometer are employed to monitor the cantilever deflection and therefore observe biological binding between a species of interest and an activated cantilever. Proof-of-concept experiments show that the sensor is capable of detecting pathogen concentration with down to a level of 105cfu/ml.

  19. Secure Communication System Basedon Chaosin Optical Fibre

    Institute of Scientific and Technical Information of China (English)

    Pak L Chu; Fan Zhang; William Mak; Robust Lai

    2003-01-01

    @@ 1 Introduction Recently, there have been intense research activities on the study of synchronized chaos generated by fibre lasers [1] and its application to secure communication systems . So far, all studies concentrate on two aspects:[2].So far,all studies concentrate on two aspects:(1) the effect of the transmission channel between the transmitter and the receiver has been neglected, and (2)the chaos and the signal are carried by one wavelength.Both theoretical and experimental investigations make these two assumptions. In the experiments, the transmission fibre is invariably short, in the order of tens of metres. Hence its dispersion and nonlinear effects are negligible. The fibre laser responsible for the generation of chaos is often designed to lase at one wavelength only.

  20. Space Division Multiplexing in Optical Fibres

    CERN Document Server

    Richardson, D J; Nelson, L E

    2013-01-01

    Optical communications technology has made enormous and steady progress for several decades, providing the key resource in our increasingly information-driven society and economy. Much of this progress has been in finding innovative ways to increase the data carrying capacity of a single optical fibre. In this search, researchers have explored (and close to maximally exploited) every available degree of freedom, and even commercial systems now utilize multiplexing in time, wavelength, polarization, and phase to speed more information through the fibre infrastructure. Conspicuously, one potentially enormous source of improvement has however been left untapped in these systems: fibres can easily support hundreds of spatial modes, but today's commercial systems (single-mode or multi-mode) make no attempt to use these as parallel channels for independent signals.

  1. Mineral fibre problems: a management view.

    Science.gov (United States)

    Hardie, H D

    1980-01-01

    Fibre is a form of matter that imparts exclusive properties to end-products; however, most fibres have been associated with health problems. Although management has a responsibility to ensure the safety of products and processes, data on which to base risk-equation decisions are often inadequate. The limitations of current dust measurement technology suggest that apparently precise numerical exposure data are as subjective as use of the terms 'heavy', 'moderate' or 'light'. Control of any useful but hazardous material is preferable to the ultimate sanction of prohibition. The man-made mineral fibre industry and national and international regulatory agencies should learn from the asbestos industry. It is suggested that a process of consultation, rather than one of confrontation, is more likely to produce widely acceptable solutions in each generation.

  2. Interfaces between a fibre and its matrix

    DEFF Research Database (Denmark)

    Lilholt, Hans; Sørensen, Bent F.

    2017-01-01

    The interface between a fibre and its matrix represents an important element in the characterization and exploitation of composite materials. Both theoretical models and analyses of experimental data have been presented in the literature since modern composite were developed and many experiments...... have been performed. A large volume of results for a wide range of composite systems exists, but rather little comparison and potential consistency have been reached for fibres and/or for matrices. Recently a materials mechanics approach has been presented to describe the interface by three parameters...... in polyester matrix. The analysis of existing experimental literature data is demonstrated for steel fibres in epoxy matrix and for tungsten wires in copper matrix. These latter incomplete analyses show that some results can be obtained even if all three experimental parameters are not recorded....

  3. Presynaptic calcium signalling in cerebellar mossy fibres

    Directory of Open Access Journals (Sweden)

    Louiza B Thomsen

    2010-02-01

    Full Text Available Whole-cell recordings were obtained from mossy fibre terminals in adult turtles in order to characterize the basic membrane properties. Calcium imaging of presynaptic calcium signals was carried out in order to analyse calcium dynamics and presynaptic GABA B inhibition. A TTX-sensitive fast Na+ spike faithfully followed repetitive depolarizing pulses with little change in spike duration or amplitude, while a strong outward rectification dominated responses to long-lasting depolarizations. High-threshold calcium spikes were uncovered following addition of potassium channel blockers. Calcium imaging using Calcium-Green dextran revealed a stimulus-evoked all-or-none tetrodotoxin (TTX -sensitive calcium signal in simple and complex rosettes. All compartments of a complex rosette were activated during electrical activation of the mossy fibre, while individual simple and complex rosettes along an axon appeared to be isolated from one another in terms of calcium signalling. CGP55845 application showed that GABA B receptors mediated presynaptic inhibition of the calcium signal over the entire firing frequency range of mossy fibres. A paired-pulse depression of the calcium signal lasting more than one second affected burst firing in mossy fibres; this paired-pulse depression was reduced by GABA B antagonists. While our results indicated that a presynaptic rosette electrophysiologically functioned as a unit, topical GABA application showed that calcium signals in the branches of complex rosettes could be modulated locally, suggesting that cerebellar glomeruli may be dynamically sub-compartmentalized due to ongoing inhibition mediated by Golgi cells. This could provide a fine-grained control of mossy fibre-granule cell information transfer and synaptic plasticity within a mossy fibre rosette.

  4. FOAM CONCRETE REINFORCEMENT BY BASALT FIBRES

    Directory of Open Access Journals (Sweden)

    Zhukov Aleksey Dmitrievich

    2012-10-01

    Full Text Available The authors demonstrate that the foam concrete performance can be improved by dispersed reinforcement, including methods that involve basalt fibres. They address the results of the foam concrete modeling technology and assess the importance of technology-related parameters. Reinforcement efficiency criteria are also provided in the article. Dispersed reinforcement improves the plasticity of the concrete mix and reduces the settlement crack formation rate. Conventional reinforcement that involves metal laths and rods demonstrates its limited application in the production of concrete used for thermal insulation and structural purposes. Dispersed reinforcement is preferable. This technology contemplates the infusion of fibres into porous mixes. Metal, polymeric, basalt and glass fibres are used as reinforcing components. It has been identified that products reinforced by polypropylene fibres demonstrate substantial abradability and deformability rates even under the influence of minor tensile stresses due to the low adhesion strength of polypropylene in the cement matrix. The objective of the research was to develop the type of polypropylene of D500 grade that would demonstrate the operating properties similar to those of Hebel and Ytong polypropylenes. Dispersed reinforcement was performed by the basalt fibre. This project contemplates an autoclave-free technology to optimize the consumption of electricity. Dispersed reinforcement is aimed at the reduction of the block settlement in the course of hardening at early stages of their operation, the improvement of their strength and other operating properties. Reduction in the humidity rate of the mix is based on the plasticizing properties of fibres, as well as the application of the dry mineralization method. Selection of optimal parameters of the process-related technology was performed with the help of G-BAT-2011 Software, developed at Moscow State University of Civil Engineering. The authors also

  5. Zeonex Microstructured Polymer Optical Fibre Bragg Grating Sensor

    DEFF Research Database (Denmark)

    Woyessa, Getinet; Fasano, Andrea; Markos, Christos

    2016-01-01

    We fabricated an endlessly single mode and humidity insensitive Zeonex microstructured polymer optical fibre (mPOF) for fibre Bragg grating (FBG) temperature and strain sensors. We inscribed and characterise FBGs in Zeonex mPOF for the first time.......We fabricated an endlessly single mode and humidity insensitive Zeonex microstructured polymer optical fibre (mPOF) for fibre Bragg grating (FBG) temperature and strain sensors. We inscribed and characterise FBGs in Zeonex mPOF for the first time....

  6. Fibre Bragg Grating Components for Filtering, Switching and Lasing

    OpenAIRE

    2008-01-01

    Fibre Bragg gratings (FBGs) are key components for a vast number of applications in optical communication systems, microwave photonics systems, and optical sensors, etc. The main topic of this thesis is fibre Bragg grating fabrication and applications in direct microwave optical filtering, high speed switching and switchable dual-wavelength fibre lasers. First, a brief overview is given about the photosensitivity in optical fibre, basic FBG fabrication techniques, the popular coupled-mode the...

  7. Facile synthesis of ZnO hollow fibres

    Indian Academy of Sciences (India)

    B T Su; K Wang; X W Zuo; H M Mu; N Dong; Y C Tong; J Bai; Z Q Lei

    2007-12-01

    In this paper, cotton fibres were used as bio-template to successfully synthesize new ceramic materials, ZnO hollow fibres and in an effort to explore the synthesis condition, and simplify the synthesis procedure. In this synthesis, a direct thermal decomposition of zinc acetate dihydrate coated on the surface of cotton fibres was explored. The wall porosity of the ZnO hollow fibres was controlled by changing the concentration of zinc acetate aqueous solution.

  8. Photonic Crystal Fibres - the State-of-the-Art

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Hansen, K. P.; Hansen, Theis Peter;

    2002-01-01

    Photonic crystal fibres having microstructured air-silica cross sections offer new optical properties compared to conventional fibres. These include novel guiding mechanisms, unique spectral properties and nonlinear possibilities. Recent results within the field are reviewed.......Photonic crystal fibres having microstructured air-silica cross sections offer new optical properties compared to conventional fibres. These include novel guiding mechanisms, unique spectral properties and nonlinear possibilities. Recent results within the field are reviewed....

  9. Mathematical Model for Fabrication of Micro-Structure Fibres

    Institute of Scientific and Technical Information of China (English)

    ZHOU Gui-Yao; HOU Zhi-Yun; LI Shu-Guang; HOU Lan-Tian

    2005-01-01

    @@ Using the classic principles of mechanics, we discuss the shape transformation of the micro-structure fibre preform under high temperature of the fibre drawing process, which leads to the theoretical relations among the structural diameter of the micro-structure fibre, the drawing technical parameter, and the physical constant of the microstructure fibre material. The theoretic values are basically in agreement with the experimental results.

  10. Fibre function and perception during cutaneous nerve block.

    Science.gov (United States)

    Mackenzie, R A; Burke, D; Skuse, N F; Lethlean, A K

    1975-09-01

    In awake human subjects, neural responses in radial nerves to electrical stimulation were recorded with intrafascicular tungsten microelectrodes. Changes in the activity of individual fibre groups during blocking procedures were recorded and correlated with simultaneous alterations in the perception of standardized stimuli. Light touch sensibility in hairy skin appeared to depend on the integrity of A-beta-gamma fibres, cold and pinprick on A-delta fibres, and warmth and dull pain on C fibres.

  11. Fabrication and applications of highly nonlinear silica holey fibres

    OpenAIRE

    Belardi, W.; Monro, T.M.; Price, J.H.V.; Lee, J.H.; Petropoulos, P.; Richardson, D J

    2001-01-01

    Holey fibre (HF) technology provides a new way to fabricate novel highly nonlinear silica based fibres. The cladding of a HF is defined by an arrangement of air holes that run along the fibre length surrounding a central silica core. The reduction in core size and increase in refractive index contrast that is possible in a HF allows the production of fibres with extremely high effective nonlinearity. HFs can also exhibit, by design of the hole configuration [2], dispersion properties not poss...

  12. The Significance of Defects on the Failure of Fibre Composites,

    Science.gov (United States)

    1981-12-01

    effects produced by discontinuous and kinked plies in unidirectional carbon fibre reinforced plastic under tension. The mean stress at failure on the...5 to6.5%) void contents on changes in torsional properties of carbon fibre reinforced plastic when exposed at various temperatures to dry or wet...properties of carbon fibre/Kevlar fibre reinforced plastic hybrid composites." RAE Technical Report 76057 (1976)* 15 G. Dorey, D.J. Portsmouth, Private

  13. Crack Growth Monitoring by Embedded Optical Fibre Bragg Grating Sensors: Fibre Reinforced Plastic Crack Growing Detection

    DEFF Research Database (Denmark)

    Pereira, Gilmar Ferreira; Mikkelsen, Lars Pilgaard; McGugan, Malcolm

    2015-01-01

    This article presents a novel method to asses a crack growing/damage event in fibre reinforced plastic, or adhesive using Fibre Bragg Grating (FBG) sensors embedded in a host material. Different features of the crack mechanism that induce a change in the FBG response were identified. Double...... Cantilever Beams specimens made with glass fibre glued with structural adhesive, were instrumented with an array of FBG sensors embedded in the material and tested using an experimental fracture procedure. A digital image correlation technique was used to determine the presence of the specific phenomena...

  14. Fibre Optical Parametric Amplification in Defect Bragg Fibres with Zero Dispersion Slow Light Effect

    Institute of Scientific and Technical Information of China (English)

    XIAO Li; ZHANG Wei; HUANG Yi-Dong; PENG Jiang-De; ZHAO Hong; YANG Ke-Wu

    2008-01-01

    Nonfinearity enhancement by slow light effect and strong light confinement in defect Bragg fibres is demonstrated and analysed in applications of fibre optical parametric amplifiers. Broadband low group velocity and zero dispersion as well as the strong light confinement by band gap enhances the nonlinear coefficient up to more than one order than the conventional high nonlinear fibres.Moreover,the zero dispersion wavelength of coupled core mode can be designed arbitrarily,under which the phase-matching bandwidth of the nonlinear process can be extended.

  15. Scientific aesthetics: three steps forward.

    Science.gov (United States)

    Chatterjee, Anjan

    2014-11-01

    Leder and Nadal (2014, this issue) examine the current state of scientific aesthetics through the lens of a prescient psychological model proposed 10 years ago. These retrospective points to several future directions of which I touch on three: the nature of aesthetic emotions, the time course of emotions in aesthetic episodes, and the relationship of art and evolution.

  16. Solution electrospinning of particle-composite fibres

    DEFF Research Database (Denmark)

    Christiansen, Lasse; Fojan, Peter

    2016-01-01

    Electrospinning is a simple and fast way to produce nano- and microfibers. By applying high voltage to a droplet of solution or polymer melt, fibre mats can be produced. These mats are porous in the micrometre domain, and have a high surface area to volume ratio.......Electrospinning is a simple and fast way to produce nano- and microfibers. By applying high voltage to a droplet of solution or polymer melt, fibre mats can be produced. These mats are porous in the micrometre domain, and have a high surface area to volume ratio....

  17. Durability of cracked fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    1998-01-01

    Durability studies are carried out at BKM as part of the research project "Design Methods for Fibre Reinforced Concrete" (FRC) involving BKM, The Concrete Research Center at DTI, Building Technology at Aalborg University, Rambøll, 4K-Beton and Rasmussen & Schiøtz. Concrete beams with or without...... structure are made on specimens drilled or sawed from beams after unloading (mechanical load). The pore structure of the concretes will be studied by microscopy, sorption and suction curves. The test programme involves three different concrete qualities (water-cement ratios). Both steel fibres (ZP...

  18. High Power Photonic Crystal Fibre Raman Laser

    Institute of Scientific and Technical Information of China (English)

    YAN Pei-Guang; RUAN Shuang-Chen; YU Yong-Qin; GUO Chun-Yu; GUO Yuan; LIU Cheng-Xiang

    2006-01-01

    A cw Raman laser based on a 100-m photonic crystal fibre is demonstrated with up to 3.8 W output power at the incident pump power of 12 W, corresponding to an optical-to-optical efficiency of about 31.6%. The second order Stokes light, which is firstly reported in a cw photonic crystal fibre Raman laser, is obtained at 1183nm with an output power of 1.6 W and a slope efficiency of about 45.7%.

  19. Spinothalamic fibres, pain conduction and cordotomy.

    Science.gov (United States)

    Moffie, D

    1975-01-01

    Description of four cases of cordotomy for intractable pain in which autopsy could be performed. In two of the cases the lesion had been placed (unintentionally) in the posterior quadrant of the spinal cord with good results as to the abolishing of pain. It is concluded that the conduction of pain and temperature stimuli is not restricted to the anterolateral part of the spinal cord but that this conduction may also take place along fibres in the posterolateral quadrant. A further conclusion is that the results of cordotomy are related to the number of cut fibres.

  20. PROSCENIUM OF SCIENTIFIC MANAGEMENT

    Directory of Open Access Journals (Sweden)

    Vasile Berlingher

    2013-09-01

    Full Text Available During the last three decades of the nineteenth century, organizations developed rapidly, their managers began to realize that they had too frequent managerial problems; this awareness lead to a new phase of development of scientific management. Examining the titles published in that period, it can be concluded that management issues that pose interest related to payroll and payroll systems, problems exacerbated by the industrial revolution and related work efficiency. Noting that large organizations losing power, direct supervision, the managers were looking for incentives to replace this power . One of the first practitioners of this new management system was Henry R. Towne, the president of the well-known enterprise "Yale and Towne Manufacturing Company", which applied the management methods in his company workshops. Publishers of magazines "Industrial Management" and "The Engineering Magazine" stated that HR Towne is, undisputedly, the pioneer of scientific management. He initiated the systematic application of effective management methods and his famous article "The Engineer as Economist" provided to the company. "American Society of Mechanical Engineers" in 1886 was the one that probably inspired Frederick W. Taylor to devote his entire life and work in scientific management.

  1. Liquid filling of photonic crystal fibres for grating writing

    DEFF Research Database (Denmark)

    Sørensen, Henrik Rokkjær; Canning, John; Lægsgaard, Jesper;

    2007-01-01

    liquid filling of photonic crystal fibres reduces the scattering from air–glass interfaces during Bragg grating writing in many layered photonic crystal fibres. Within experimental uncertainty, the grating index modulation of a grating written in germanium-doped photonic crystal fibre with 10 rings...

  2. Calculation of the conduction velocity of short nerve fibres

    NARCIS (Netherlands)

    van der Vliet, G.H.; Holsheimer, J.

    1980-01-01

    The conduction velocity v of a nerve fibre is calculated from the time delay Δ of a propagating action potential between two recording sites along the fibre. However, the conventional method of determining Δ cannot be applied to short nerve fibres. Therefore several linear signal analysis methods

  3. Optical fibre Bragg grating recorded in TOPAS cyclic olefin copolymer

    DEFF Research Database (Denmark)

    Johnson, I.P.; Yuan, Scott Wu; Stefani, Alessio

    2011-01-01

    A report is presented on the inscription of a fibre Bragg grating into a microstructured polymer optical fibre fabricated from TOPAS cyclic olefin copolymer. This material offers two important advantages over poly (methyl methacrylate), which up to now has formed the basis for polymer fibre Bragg...

  4. Design of fibre reinforced PV concepts for building integrated applications

    NARCIS (Netherlands)

    Reinders, Angelina H.M.E.; de Wit, H.; de Boer, Andries; Ossenbrink Sinke, W.; Helm, P.

    2009-01-01

    Fibre reinforced polymers present an interesting encapsulation medium for PV-modules. Glass fibres can provide increased strength and stiffness to thin polymer layers overcoming the brittleness and limited deformability of glass-panes. Glass fibre reinforced polymers allows for transparency over a

  5. Mechanical properties of short-flax-fibre reinforced compounds

    NARCIS (Netherlands)

    Bos, H.L.; Müssig, J.; Oever, van den M.J.A.

    2006-01-01

    The mechanical properties of flax/polypropylene compounds, manufactured both with a batch kneading and an extrusion process were determined and compared with the properties of Natural fibre Mat Thermoplastic (NMT) composites. The fibre length and width distributions of the fibres from the compounds

  6. Modelling fibre laydown and web uniformity in nonwoven fabric

    Science.gov (United States)

    Battocchio, F.; Sutcliffe, M. P. F.

    2017-04-01

    The mechanical and functional performance of nonwoven fabric critically depends on the fibre architecture. The fibre laydown process plays a key role in controlling this architecture. The fibre dynamic behaviour during laydown is studied through a finite element model which describes the role of the parameters in defining the area covered by a single fibre when deposited on the conveyor belt. The path taken by a fibre is described in terms of the radius of gyration, which characterises the area covered by the fibre in the textile, and the spectrum of curvature, which describes the degree of fibre looping as a function of the arc length. Starting from deterministic and idealised fibre curvature spectra, stochastic Monte Carlo simulations are undertaken to generate full nonwoven web samples and reproduce the uniformity of fibre density. A novel image analysis technique that allows measurement of the uniformity of real spunbonded nonwoven samples from images of textiles is used to confirm the validity of the model. It is shown that the main parameter that governs the fibre density uniformity is the ratio of the fibre spinning velocity to the velocity of conveyor belt, while fibre oscillations prior to deposition play a secondary role.

  7. Wet spinning of asymmetric hollow fibre membranes for gas separation

    NARCIS (Netherlands)

    Hof, van 't Jacob Adriaan

    1988-01-01

    This thesis describes the spinning and characterizatin of hollow fibre membranes for gas separation. The type of fibres studied here are made by a wet spinning process. A homogeneous solution is prepared, consisting of a polymer in a suitable organic solvent, and extruded as a hollow fibre. Both the

  8. Environmental impact assessment of man-made cellulose fibres

    NARCIS (Netherlands)

    Shen, L.; Worrell, E.; Patel, M.K.

    2010-01-01

    Man-made cellulose fibres have played an important role in the production of textile products for more than 70 years. The purpose of this study is to assess the environmental impact of man-made cellulose fibres. Life cycle assessment (LCA) was conducted for three types of fibres (i.e. Viscose, Modal

  9. Wet spinning of asymmetric hollow fibre membranes for gas separation

    NARCIS (Netherlands)

    van 't Hof, Jacob Adriaan

    1988-01-01

    This thesis describes the spinning and characterizatin of hollow fibre membranes for gas separation. The type of fibres studied here are made by a wet spinning process. A homogeneous solution is prepared, consisting of a polymer in a suitable organic solvent, and extruded as a hollow fibre. Both the

  10. Environmental impact assessment of man-made cellulose fibres

    NARCIS (Netherlands)

    Shen, L.; Worrell, E.; Patel, M.K.

    2010-01-01

    Man-made cellulose fibres have played an important role in the production of textile products for more than 70 years. The purpose of this study is to assess the environmental impact of man-made cellulose fibres. Life cycle assessment (LCA) was conducted for three types of fibres (i.e. Viscose, Modal

  11. CLEAVAGE OF SOFTWOOD KRAFT PULP FIBRES BY HCL AND CELLULASES

    Directory of Open Access Journals (Sweden)

    Paul Ander

    2008-05-01

    Full Text Available A new pulp fibre testing procedure called the HCl method was used to compare different spruce and pine fibres and mixtures of these fibres to calculate number of fibre cleavages in dislocations and other weak points. This method was compared with treatment of softwood kraft pulp fibres using different cellulase mixtures. The HCl method can distinguish between mill- and laboratory-made softwood kraft pulp fibres from the same wood batch. The sugar release is characterized by xylose and other hemicellulose sugars and little glucose. This is in contrast to cellulases, which despite strong fibre cleavage, did not distinguish between mill- and laboratory-made pulp fibres and released large amounts of glucose from the fibres. Hemicellulose degradation by HCl and deep penetration of the acid into the primary and secondary fibre cell walls at 80°C seems to be of major importance for the differentiation between mill and laboratory pulp fibres. Cellulases, in contrast, act mostly on the fibre surfaces, and deep penetration only takes place in amorphous regions of dislocations.

  12. Design of fibre reinforced PV concepts for building integrated applications

    NARCIS (Netherlands)

    Reinders, A.H.M.E.; Wit, de H.; Boer, de A.

    2009-01-01

    Fibre reinforced polymers present an interesting encapsulation medium for PV-modules. Glass fibres can provide increased strength and stiffness to thin polymer layers overcoming the brittleness and limited deformability of glass-panes. Glass fibre reinforced polymers allows for transparency over a b

  13. Biodegradable hollow fibres for the controlled release of hormones

    NARCIS (Netherlands)

    Eenink, M.J.D.; Feijen, Jan; Olijslager, J.; Albers, J.H.M.; Rieke, J.C.; Greidanus, P.J.

    1987-01-01

    Poly(l-lactide), (PLLA), hollow fibres were prepared using a dry-wet phase inversion spinning process. The effect of several spinning parameters (i.e. bore medium flow rate, spinning dope extrusion rate, fibre take-up rate, and spinning height) on the hollow fibre dimensions is reported. The use of

  14. Biodegradable hollow fibres for the controlled release of hormones

    NARCIS (Netherlands)

    Eenink, M.J.D.; Feijen, J.; Olijslager, J.; Albers, J.H.M.; Rieke, J.C.; Greidanus, P.J.

    1987-01-01

    Poly(l-lactide), (PLLA), hollow fibres were prepared using a dry-wet phase inversion spinning process. The effect of several spinning parameters (i.e. bore medium flow rate, spinning dope extrusion rate, fibre take-up rate, and spinning height) on the hollow fibre dimensions is reported. The use of

  15. Surface charges in blending short fibres with polyethylene powder

    NARCIS (Netherlands)

    Hofste, JM; Kersten, MJE; van Turnhout, J; Pennings, AJ

    1998-01-01

    Short fibres and ultra-high molecular weight polyethylene (UHMWPE) powder were mixed by swirling in a glass jar with compressed nitrogen. It was found that a kind of attraction between the fibres and UHMWPE particles is crucial for making a composite with a proper fibre distribution. If aramid and U

  16. Tensile behaviour of polyethylene and poly(p-xylylene) fibres

    NARCIS (Netherlands)

    van der Werff, Harm

    1991-01-01

    This thesis deals with the tensile behaviour of fibres prepared from high molecular weight polymers.The tensile strength of a polymeric fibre is in general much lower than the corresponding theoretical value. In case of ultra-high molecular weight polyethylene (UHMWPE), fibres can be prepared by gel

  17. Microbending in photonic crystal fibres - an ultimate loss limit?

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Hansen, Theis Peter; Hougaard, Kristian G.;

    2001-01-01

    Microbending losses are for the first time estimated in index-guiding photonic crystal fibres, and comparisons with standard step-index fibres are made. The results indicate that typical photonic crystal fibres are significantly less sensitive (one order of magnitude smaller loss) towards...

  18. Determinants and clinical application of muscle fibre conduction velocity

    NARCIS (Netherlands)

    Blijham, P.J.

    2007-01-01

    A muscle fibre can be excited by electrical stimulation using a needle electrode. Action potentials elicited this way will be conducted through the muscle fibre and can be recorded at some distance with a second needle electrode. This way, muscle fibre conduction velocity can be estimated. In the pr

  19. Nd3+ Doped Silicate Glass Photonic Crystal Fibres

    Institute of Scientific and Technical Information of China (English)

    YANG Lu-Yun; CHEN Dan-Ping; XIA Jin-An; WANG Chen; JIANG Xiong-Wei; ZHU Cong-Shan; QIU Jian-Rong

    2005-01-01

    @@ We report on the fabrication of two kinds of large core area Nd3+ doped silicate glass photonic crystal fibres, and demonstration of the fibre waveguiding properties. The measured minimum loss of one kind ofibres is 2.5 db/m at 660nm. The fibres sustain only a single mode at least over the wavelength range from 660nm to 980nm.

  20. Inhibition of starch absorption by dietary fibre. A comparative study of wheat bran, sugar-beet fibre, and pea fibre

    DEFF Research Database (Denmark)

    Hamberg, O; Rumessen, J J; Gudmand-Høyer, E

    1989-01-01

    -20%) (p less than 0.01), and 12% (5-27%) (p less than 0.01), respectively. Bread made from 100 g of low-gluten wheat flour only escaped small-bowel absorption in three subjects with a maximal fraction of 6% (p less than 0.05). All three fibres decreased mouth-to-caecum transit time. We conclude...