WorldWideScience

Sample records for internal crystal generator

  1. Laser generated soliton waveguides in photorefractive crystals

    International Nuclear Information System (INIS)

    Vlad, V.I.; Fazio, E.; Bertolotti, M.; Bosco, A.; Petris, A.

    2005-01-01

    Non-linear photo-excited processes using the photorefractive effect are revisited with emphasis on spatial soliton generation in special laser beam propagation conditions. The soliton beams can create reversible or irreversible single-mode waveguides in the propagating materials. The important features are the 3D orientation and graded index profile matched to the laser fundamental mode. Bright spatial solitons are theoretically demonstrated and experimentally observed for the propagation of c.w. and pulsed femtosecond laser beams in photorefractive materials such as Bi 12 SiO 20 (BSO) and lithium niobate crystals. Applications in high coupling efficiency, adaptive optical interconnections and photonic crystal production are possible

  2. Internal bias field in glycine phosphite crystal

    International Nuclear Information System (INIS)

    Nayeem, Jannatul; Wakabayashi, Hiroshi; Kikuta, Toshio; Yamazaki, Toshinari; Nakatani, Noriyuki

    2003-01-01

    The distributions of internal bias field E b have been investigated under the carbon-powder pattern and mercury electrode techniques in GPI ferroelectric crystals. Polarity and intensity of E b are distributed depending on crystal growth sectors. Crystal symmetry 2/m is observed obviously in the distribution of E b . The polarities of E b are head-to-head manner in those growth sectors where a surface is growing parallel to the crystallographic a-axis and tail-to-tail manner in the other growth sectors in the crystal. The maximum intensity of E b is found in the sectors (010) where the growing surfaces are perpendicular to the ferroelectric b-axis

  3. Supercontinuum Generation in a Photonic Crystal Fibre

    Institute of Scientific and Technical Information of China (English)

    YAN Pei-Guang; RUAN Shuang-Chen; LIN Hao-Jia; DU Chen-Lin; YU Yong-Qin; LU Ke-Cheng; YAO Jian-Quan

    2004-01-01

    @@ Nearly 1000-nm broad continuum from 390nm to 1370nm is generated in a 2-m long photonic crystal fibre. The maximum total power of supercontinuum is measured to be 60mW with the pumping power of 800mW output from a 200-fs Ti:sapphire laser. The evolution of the pumping light into supercontinuum is experimentally studied in detail. It is found that the mechanism for supercontinuum generation has direct relations with Raman effect and soliton effect, and the four-wave mixing plays an important role in the last phase of the supercontinuum generation.

  4. Generation IV reactors: international projects

    International Nuclear Information System (INIS)

    Carre, F.; Fiorini, G.L.; Kupitz, J.; Depisch, F.; Hittner, D.

    2003-01-01

    Generation IV international forum (GIF) was initiated in 2000 by DOE (American department of energy) in order to promote nuclear energy in a long term view (2030). GIF has selected 6 concepts of reactors: 1) VHTR (very high temperature reactor system, 2) GHR (gas-cooled fast reactor system), 3) SFR (sodium-cooled fast reactor system, 4) SCWR (super-critical water-cooled reactor system), 5) LFR (lead-cooled fast reactor system), and 6) MFR (molten-salt reactor system). All these 6 reactor systems have been selected on criteria based on: - a better contribution to sustainable development (through their aptitude to produce hydrogen or other clean fuels, or to have a high energy conversion ratio...) - economic profitability, - safety and reliability, and - proliferation resistance. The 6 concepts of reactors are examined in the first article, the second article presents an overview of the results of the international project on innovative nuclear reactors and fuel cycles (INPRO) within IAEA. The project finished its first phase, called phase-IA. It has produced an outlook into the future role of nuclear energy and defined the need for innovation. The third article is dedicated to 2 international cooperations: MICANET and HTR-TN. The purpose of MICANET is to propose to the European Commission a research and development strategy in order to develop the assets of nuclear energy for the future. Future reactors are expected to be more multiple-purposes, more adaptable, safer than today, all these developments require funded and coordinated research programs. The aim of HTR-TN cooperation is to promote high temperature reactor systems, to develop them in a long term perspective and to define their limits in terms of burn-up and operating temperature. (A.C.)

  5. Second harmonic generation in Te crystal using free electron laser

    CERN Document Server

    Yamauchi, T; Minehara, E J

    2002-01-01

    The second harmonic generation signal converted from the fundamental wavelength of 22 mu m of a free electron laser was observed for the first time using a birefringent Te crystal. The experimental conversion efficiency of Te crystal for second harmonic generation is 0.53%, which is equivalent to the theoretical value within a factor of 2. The Te crystal has been incorporated into an autocorrelator system to measure the micro-pulse width of infrared free electron laser successfully. (author)

  6. Macromolecular crystallization in microgravity generated by a superconducting magnet.

    Science.gov (United States)

    Wakayama, N I; Yin, D C; Harata, K; Kiyoshi, T; Fujiwara, M; Tanimoto, Y

    2006-09-01

    About 30% of the protein crystals grown in space yield better X-ray diffraction data than the best crystals grown on the earth. The microgravity environments provided by the application of an upward magnetic force constitute excellent candidates for simulating the microgravity conditions in space. Here, we describe a method to control effective gravity and formation of protein crystals in various levels of effective gravity. Since 2002, the stable and long-time durable microgravity generated by a convenient type of superconducting magnet has been available for protein crystal growth. For the first time, protein crystals, orthorhombic lysozyme, were grown at microgravity on the earth, and it was proved that this microgravity improved the crystal quality effectively and reproducibly. The present method always accompanies a strong magnetic field, and the magnetic field itself seems to improve crystal quality. Microgravity is not always effective for improving crystal quality. When we applied this microgravity to the formation of cubic porcine insulin and tetragonal lysozyme crystals, we observed no dependence of effective gravity on crystal quality. Thus, this kind of test will be useful for selecting promising proteins prior to the space experiments. Finally, the microgravity generated by the magnet is compared with that in space, considering the cost, the quality of microgravity, experimental convenience, etc., and the future use of this microgravity for macromolecular crystal growth is discussed.

  7. The changing face of international power generation

    Energy Technology Data Exchange (ETDEWEB)

    Lindsay, I. [World Energy Council, London (United Kingdom)

    1997-12-31

    The author limits his remarks to a discussion of the international generator`s marketplace, especially aimed at the developing countries. He discusses future global electricity demand, generating capacity build, its financing issues, and to the commercial generating opportunities which now abound outside the US.

  8. Laser generation in opal-like single-crystal and heterostructure photonic crystals

    Science.gov (United States)

    Kuchyanov, A. S.; Plekhanov, A. I.

    2016-11-01

    This study describes the laser generation of a 6Zh rhodamine in artificial opals representing single-crystal and heterostructure films. The spectral and angular properties of emission and the threshold characteristics of generation are investigated. In the case where the 6Zh rhodamine was in a bulk opal, the so-called random laser generation was observed. In contrast to this, the laser generation caused by a distributed feedback inside the structure of the photonic bandgap was observed in photonic-crystal opal films.

  9. Large photovoltages generated by plant photosystem I crystals

    Energy Technology Data Exchange (ETDEWEB)

    Toporik, Hila; Carmeli, Chanoch; Nelson, Nathan [Department of Biochemistry and Molecular Biology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978 (Israel); Carmeli, Itai [School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel); Volotsenko, Irina; Molotskii, Michel; Rosenwaks, Yossi [Department of Physical Electronics, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel)

    2012-06-12

    Micrometer-thick plant photosystem I crystals made of up to 1000 layers of serially arranged protein complexes generate unprecedented high photovoltages when placed on a conducting solid surface and measured using Kelvin probe force microscopy. The successive layers form serially photoinduced dipoles in the crystal that give rise to electric fields as large as 100 kV cm{sup -1}. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Third international seminar on horizontal steam generators

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The Third International Seminar on Horizontal Steam Generators held on October 18-20, 1994 in Lappeenranta, consisted of six sessions dealing with the topics: thermal hydraulic experiments and analyses, primary collector integrity, management of primary-to-secondary leakage accidents, feedwater collector replacement and discussion of VVER-440 steam generator safety issues.

  11. Third international seminar on horizontal steam generators

    International Nuclear Information System (INIS)

    1995-01-01

    The Third International Seminar on Horizontal Steam Generators held on October 18-20, 1994 in Lappeenranta, consisted of six sessions dealing with the topics: thermal hydraulic experiments and analyses, primary collector integrity, management of primary-to-secondary leakage accidents, feedwater collector replacement and discussion of VVER-440 steam generator safety issues

  12. Third international seminar on horizontal steam generators

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    The Third International Seminar on Horizontal Steam Generators held on October 18-20, 1994 in Lappeenranta, consisted of six sessions dealing with the topics: thermal hydraulic experiments and analyses, primary collector integrity, management of primary-to-secondary leakage accidents, feedwater collector replacement and discussion of VVER-440 steam generator safety issues.

  13. Generation of ionizing radiation from lithium niobate crystals

    Science.gov (United States)

    Orlikov, L. N.; Orlikov, N. L.; Arestov, S. I.; Mambetova, K. M.; Shandarov, S. M.

    2017-01-01

    The work done experimentally explores generation of electron and x-ray radiation in the process of heating and cooling monolithic and iron-doped crystals of lithium niobate. Iron doping to the concentrations in the range of 1023 m3 was carried out by adding ferric oxide into the melt during the process of crystal growth. The research into radiation generation was performed at 1-10 Pa. The speed of heating from -10 to 1070 C was 10-20 degrees a minute. Current pulses appeared at 17, 38, 56, 94, 98, 100, 105, 106, 1070 C with the interval of 1-3 minutes. The obtained electron current increased in direct proportion to the crystal surface area. The maximum current was 3mA at the design voltage 11 kV on the crystal with 14,5x10,5x10 mm3 surface area. The article describes the possibility to control the start of generation by introducing priming pulse. The results achieved are explained by the domain repolarization while heating the crystal and the appearance of electric field local strength. Bias and overcharge currents contribute to the appearance of electric strength, which stimulates breakdown and plasma formation. X-ray radiation appears both at the stage of discharge formation and during electron deceleration on gas and target material.

  14. Supercontinuum Generation in Uniform and Tapered Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Sørensen, Simon Toft; Møller, Uffe Visbech; Larsen, Casper

    Supercontinuum generation (SCG) is a striking phenomenon of extreme spectral broadening involving a wealth of beautiful nonlinear physics. The study of SCG and development of today’s commercial sources really took off with the invention of the photonic crystal fiber (PCF), in which light can be m...

  15. Initial steps of supercontinuum generation in photonic crystal fibers

    DEFF Research Database (Denmark)

    Hilligsøe, Karen Marie; Paulsen, H.N.; Thøgersen, J.

    2003-01-01

    The onset of supercontinuum generation in a photonic crystal fiber is investigated experimentally and numerically as a function of pump wavelength and intensity with 100-fs pulses. Soliton formation is found to be the determining factor in the initial step. The formation and behavior of a blueshi...

  16. Soliton fission and supercontinuum generation in photonic crystal

    Indian Academy of Sciences (India)

    2015-10-17

    Oct 17, 2015 ... We present a practical design of novel photonic crystal fibre (PCF) to investigate the nonlinear propagation of femtosecond pulses for the application of optical coherence tomography (OCT) based on supercontinuum generation (SCG) process. In addition, this paper contains a brief introduction of the ...

  17. Kinetics of barium sulphate reaction crystallization in crystallizers with internal circulation

    Directory of Open Access Journals (Sweden)

    J. Koralewska

    2008-06-01

    Full Text Available Kinetic calculation results describing the observed nucleation and growth rates of barium sulphate crystals precipitated in an integrated reaction-crystallization process in a barium sulphate-ammonium chloride-water system are presented and analyzed. The scope of experiments included two continuous model DTM-type crystallizers (Draft Tube Magma with internal circulation of the suspension forced by a liquid jet-pump device responsible for stable and intensive enough ascending/descending flow of BaSO4 crystal magma in a mixing chamber. For comparison purposes the experimental data corresponding to a continuous DT (Draft Tube crystallizer with propeller agitator are presented and discussed. The various types of laboratory crystallizers used were fed with concentrated water solution of barium chloride (of 10 or 24 mass % and - in a stoichiometric proportion - crystalline ammonium sulphate, assuming isothermal (348 K and hydrodynamic (average residence time of suspension in a crystallizer: 900 s process conditions. The observed nucleation and growth rates of barium sulphate crystals were estimated on the basis of crystal size distributions (CSDs using convenient calculation scheme derived for an MSMPR (Mixed Suspension Mixed Product Removal model approach. Considering the experimental population density distribution courses, a size-dependent growth (SDG phenomenon was taken into account in the kinetic calculations. Five SDG kinetic models recommended in the accessible literature were used for kinetic parameter values estimation. It was proved statistically, that Rojkowski’s two SDG models (hyperbolic and exponential best suit for our own experimental data description. The experimental data presented can be practically applied for improving the constructions of liquid jet-pump DTM crystallizers recommended for reaction crystallization of sparingly soluble inorganic salts (especially for high concentrations of reaction substrates in the modern

  18. Fourth international seminar on horizontal steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Tuomisto, H. [ed.] [IVO Group, Vantaa (Finland); Purhonen, H. [ed.] [VTT, Espoo (Finland); Kouhia, V. [ed.] [Lappeenranta Univ. of Technology (Finland)

    1997-12-31

    The general objective of the International Seminars of Horizontal Steam Generator Modelling has been the improvement in understanding of realistic thermal hydraulic behaviour of the generators when performing safety analyses for VVER reactors. The main topics presented in the fourth seminar were: thermal hydraulic experiments and analyses, primary collector integrity, feedwater distributor replacement, management of primary-to-secondary leakage accidents and new developments in the VVER safety technology. The number of participants, representing designers and manufacturers of the horizontal steam generators, plant operators, engineering companies, research organizations, universities and regulatory authorities, was 70 from 10 countries.

  19. Fourth international seminar on horizontal steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Tuomisto, H [ed.; IVO Group, Vantaa (Finland); Purhonen, H [ed.; VTT, Espoo (Finland); Kouhia, V [ed.; Lappeenranta Univ. of Technology (Finland)

    1998-12-31

    The general objective of the International Seminars of Horizontal Steam Generator Modelling has been the improvement in understanding of realistic thermal hydraulic behaviour of the generators when performing safety analyses for VVER reactors. The main topics presented in the fourth seminar were: thermal hydraulic experiments and analyses, primary collector integrity, feedwater distributor replacement, management of primary-to-secondary leakage accidents and new developments in the VVER safety technology. The number of participants, representing designers and manufacturers of the horizontal steam generators, plant operators, engineering companies, research organizations, universities and regulatory authorities, was 70 from 10 countries.

  20. Fourth international seminar on horizontal steam generators

    International Nuclear Information System (INIS)

    Tuomisto, H.; Purhonen, H.; Kouhia, V.

    1997-01-01

    The general objective of the International Seminars of Horizontal Steam Generator Modelling has been the improvement in understanding of realistic thermal hydraulic behaviour of the generators when performing safety analyses for VVER reactors. The main topics presented in the fourth seminar were: thermal hydraulic experiments and analyses, primary collector integrity, feedwater distributor replacement, management of primary-to-secondary leakage accidents and new developments in the VVER safety technology. The number of participants, representing designers and manufacturers of the horizontal steam generators, plant operators, engineering companies, research organizations, universities and regulatory authorities, was 70 from 10 countries

  1. Preventing Crystal Agglomeration of Pharmaceutical Crystals Using Temperature Cycling and a Novel Membrane Crystallization Procedure for Seed Crystal Generation

    Directory of Open Access Journals (Sweden)

    Elena Simone

    2018-01-01

    Full Text Available In this work, a novel membrane crystallization system was used to crystallize micro-sized seeds of piroxicam monohydrate by reverse antisolvent addition. Membrane crystallization seeds were compared with seeds produced by conventional antisolvent addition and polymorphic transformation of a fine powdered sample of piroxicam form I in water. The membrane crystallization process allowed for a consistent production of pure monohydrate crystals with narrow size distribution and without significant agglomeration. The seeds were grown in 350 g of 20:80 w/w acetone-water mixture. Different seeding loads were tested and temperature cycling was applied in order to avoid agglomeration of the growing crystals during the process. Focused beam reflectance measurement (FBRM; and particle vision and measurement (PVM were used to monitor crystal growth; nucleation and agglomeration during the seeded experiments. Furthermore; Raman spectroscopy was used to monitor solute concentration and estimate the overall yield of the process. Membrane crystallization was proved to be the most convenient and consistent method to produce seeds of highly agglomerating compounds; which can be grown via cooling crystallization and temperature cycling.

  2. Generation 4 International Forum. 2007 annual report

    International Nuclear Information System (INIS)

    2007-01-01

    This annual report is the first to be issued by GIF (Generation IV International Forum). It summarizes the GIF goals and accomplishments throughout 2007, describes its membership and organization, and provides an overview of its cooperation with other international endeavors for the development of nuclear energy. Future editions will focus on technical progress. Chapter 2 provides an overview on the goals of Generation IV nuclear energy systems and outlines the main characteristics of the six systems selected for joint development by GIF (VHTR - Very High Temperature Reactor; SFR - Sodium-cooled Fast Reactor; SCWR - Super-Critical Water cooled Reactor; GFR - Gas-cooled Fast Reactor; LFR - Lead-cooled Fast Reactor; and MSR - Molten Salt Reactor). Chapter 3 describes the membership and organization of the GIF, the structure of its cooperative research and development (R-D) arrangements, and the status of Member participation in these arrangements. Chapter 4 summarizes the R-D plans and achievements of the Forum until now. It highlights the R-D challenges facing the teams developing Generation IV systems and the major milestones towards the development of these systems. It also describes the progress made regarding the development of methodologies for assessing Generation IV systems with respect to the established goals. Chapter 5 reviews other major international collaborative projects in the field of nuclear energy and explains how the GIF interacts and cooperates with them. Bibliographical references are provided in each chapter in order to facilitate access to public information about the GIF objectives, goals and outcomes

  3. Generation 4 International Forum. 2008 annual report

    International Nuclear Information System (INIS)

    2008-01-01

    This 2008 Annual Report is the second annual report issued by GIF (Generation IV International Forum). It provides an update on the GIF organization, membership, and participation in research and development (R-D) projects for each Generation IV system. It summarizes the milestones for development of each system and progress of the R-D toward their accomplishment. Finally, it includes a brief description of the cooperation between GIF and other international endeavors for the development of nuclear energy. Chapter 2 describes the membership and organization of the GIF, the structure of its cooperative research and development arrangements, and the status of Member participation in those arrangements. Chapter 3 provides a summary of the GIF R-D plans, and its activities and achievements during 2008. It highlights the R-D challenges facing the teams developing Generation IV systems and the major milestones towards the development of these systems. It also describes the progress made regarding the development of methodologies for assessing Generation IV systems with respect to the established goals of GIF. Chapter 4 reviews other major international collaborative projects in the field of nuclear energy and explains how the GIF interacts and cooperates with them. Appendix 1 provides an overview on the goals of Generation IV nuclear energy systems and outlines the main characteristics of the six systems selected for joint development by GIF. The list of abbreviations and acronyms given at the end of the report defines terms used in the various chapters including various nuclear energy systems and international programs referred to in connection with GIF R-D activities. Some bibliographical references are given in order to facilitate access to public information about R-D progress and achievements on specific technical issues for GIF systems

  4. Macromolecular Crystallization in Microfluidics for the International Space Station

    Science.gov (United States)

    Monaco, Lisa A.; Spearing, Scott

    2003-01-01

    At NASA's Marshall Space Flight Center, the Iterative Biological Crystallization (IBC) project has begun development on scientific hardware for macromolecular crystallization on the International Space Station (ISS). Currently ISS crystallization research is limited to solution recipes that were prepared on the ground prior to launch. The proposed hardware will conduct solution mixing and dispensing on board the ISS, be fully automated, and have imaging functions via remote commanding from the ground. Utilizing microfluidic technology, IBC will allow for on orbit iterations. The microfluidics LabChip(R) devices that have been developed, along with Caliper Technologies, will greatly benefit researchers by allowing for precise fluid handling of nano/pico liter sized volumes. IBC will maximize the amount of science return by utilizing the microfluidic approach and be a valuable tool to structural biologists investigating medically relevant projects.

  5. Generation 4 International Forum. 2009 annual report

    International Nuclear Information System (INIS)

    2009-01-01

    This 2009 Annual Report is the third annual report issued by GIF (Generation 4. International Forum). It includes 3 chapters in addition to an introduction plus 4 appendices, as follows. Chapter 2 describes the membership and organization of GIF, the structure of its cooperative research and development arrangements as well as the status of Members' participation in such arrangements. Chapter 3 summarizes GIF research and development plans, activities and achievements during 2009. It highlights the scientific and technical challenges facing the teams developing Generation IV systems and the major milestones towards the development of these systems. It also describes the progress made on the development of methodologies for assessing Generation IV systems with respect to the established goals of GIF. Chapter 4 reviews the cooperation between GIF and other international programs dealing with the development of nuclear energy. Appendix 1 provides an overview on the goals of Generation IV nuclear energy systems and an outline of the main characteristics of the six systems selected for joint development by GIF. Appendix 2 presents the objectives that have been set for the various System Steering Committees and the associated Project Management Boards for the next 5 years. Appendix 3 reproduces the Table of Contents of the Proceedings from the GIF Symposium held in Paris (France) in 2009. Appendix 4 provides a list of abbreviations and acronyms (with the corresponding definitions) which are used in this report or are relevant to GIF activities

  6. Generation IV international forum 2002 - remarks

    International Nuclear Information System (INIS)

    Abraham, S.

    2002-01-01

    Analyses and forecasts underscore the important role of nuclear power in energy supply in the 21st century. Important aspects in this respect are the conservation of fossil resources, the protection of the world's climate, and the continuity of supply. Present 1st and 2nd generation nuclear power plants ensure an economical and technically mature electricity supply. Advanced systems offering, e.g., higher efficiency of fuel utilization, simplified systems technology, and advanced safety characteristics, can make available additional benefits in using nuclear power. Upon an initiative of the U.S. Department of Energy (DOE), ten countries combine their efforts in developing such reactor concepts in the Generation IV International Forum (GIF). Argentina, Brazil, Canada, France, Japan, South Africa, South Korea, Switzerland, the United Kingdom, and the United States pursue the common objective in GIF to identify suitable nuclear power systems and promote their development up to the envisaged readiness for construction in 2030. Besides technical and economic questions of nuclear power generation, also other aspects must be considered with a view to the future use of nuclear power. The particularly relevant issues, such as the management of radioactive waste, the intensification of research and development, and international cooperation, have been taken up by the Bush administration at an early point in time and have been, or will be, incorporated in practical solutions, as in the case of the Yucca Mountain repository project. (orig.)

  7. Generation 4 International Forum. 2014 Annual Report

    International Nuclear Information System (INIS)

    2015-01-01

    This eighth edition of the Generation IV International Forum (GIF) Annual Report highlights the main achievements of the Forum in 2014, and in particular progress made in the collaborative RandD activities of the eleven existing project arrangements for the six GIF systems: the gas-cooled fast reactor, the sodium-cooled fast reactor, the supercritical-water-cooled reactor and the very-high-temperature reactor. Progress made under the memoranda of understanding for the lead-cooled fast reactor and the molten salt reactor is also reported. In May 2014, China joined the supercritical-water-cooled reactor system arrangement; and in October 2014, the project arrangement on system integration and assessment for the sodium-cooled fast reactor became effective. GIF also continued to develop safety design criteria and guidelines for the sodium-cooled fast reactor, and to engage with regulators on safety approaches for generation IV systems. Finally, GIF initiated an internal discussion on sustainability approaches to complement ongoing work on economics, safety, proliferation resistance and physical protection

  8. International cost relations in electric power generation

    International Nuclear Information System (INIS)

    Schmitt, D.; Duengen, H.; Wilhelm, M.

    1986-01-01

    In spite of the fact that analyses of the cost of electric power generation as the result of international comparative evaluations are indisputably relevant, problems pending in connection with the costs of representative power plant technologies are of the methodological bind. German authors have hitherto also been failing to clear up and consider all aspects connected with the problems of data acquisition and the adequate interpretation of results. The analysis presented by the paper abstracted therefore aims at the following: 1) Systematization of the different categories of cost relevant in connection with international comparative evaluation. Classification into different categories of decision making and development of standards meeting the requirements of international comparative evaluation. 2) Calculation of relevant average financial costs of Western German, America and French fossil-fuel and nuclear power plants by means of adequate calculation models, that is the assessment of costs with regard to countries and power plant technologies which are relevant to the Federal Republic of Germany. 3) Analysis of the resulting differences and determinantal interpretation. (orig./UA) [de

  9. Fifth CNS international steam generator conference

    International Nuclear Information System (INIS)

    2006-01-01

    The Fifth CNS International Steam Generator Conference was held on November 26-29, 2006 in Toronto, Ontario, Canada. In contrast with other conferences which focus on specific aspects, this conference provided a wide ranging forum on nuclear steam generator technology from life-cycle management to inspection and maintenance, functional and structural performance characteristics to design architecture. The 5th conference has adopted the theme: 'Management of Real-Life Equipment Conditions and Solutions for the Future'. This theme is appropriate at a time of transition in the industry when plants are looking to optimize the performance of existing assets, prevent costly degradation and unavailability, while looking ahead for new steam generator investments in life-extension, replacements and new-build. More than 50 technical papers were presented in sessions that gave an insight to the scope: life management strategies; fouling, cleaning and chemistry; replacement strategies and new build design; materials degradation; condition assessment/fitness for service; inspection advancements and experience; and thermal hydraulic performance

  10. Internal ultrasonic testing of steam generator tubes

    International Nuclear Information System (INIS)

    Furlan, J.; Soleille, G.; Chalaye, H.

    1983-01-01

    The ''in situ'' inspection of steam generator tubes uses generally Foucault currents before starting and along its life. This inspection aims at searching cracks and corrosion defects. The Foucault current method is quite badly adapted to ''closed crack'' detection, for it doesn't introduce neither resistivity or magnetic permeability variation, or lack of matter. More, it is sensible to the magnetic properties of the tube itself and to its environment (tubular or support plates). It is why, this first systematic inspection has to be completed by an ultrasonic one allowing to bring new elements in the uncertain cases. A device with an internal probe has been developed. It ''lights'' the tube wall with the aid of a transducer of which beam reflects on a mirror. Operating conditions are the same as for Foucault current testing, that is to say the probe moves inside the tube without rotation of the device (bent parts are excluded) [fr

  11. International comparison of electricity generating costs

    International Nuclear Information System (INIS)

    Jones, P.M.S.; Stevens, G.H.; Wigley, K.

    1989-01-01

    The paper reviews the principal findings of successive studies of projected comparative generation costs for base-load electricity production conducted by Nuclear Energy Agency working groups, including a current study jointly sponsored by the International Energy Agency. It concludes that over the six years 1983-1989 nuclear generation costs have remained steady or slightly declined in the majority of OECD countries. This represents an excellent result in view of the difficulties that have arisen in many countries during the period. Nuclear power is projected to maintain a significant advantage in most OECD countries on an assessment basis reflecting utility experience and discount rates employed by the majority of participants. However, nuclear's projected advantage has declined due to a significant fall in projected coal prices which have decreased by 50% since 1983. This decline is only slightly offset by increased capital and operating costs for coal-fired plant. If rates of return sought by utilities were higher or if coal prices prove lower than utilities project then the economic balance between nuclear and coal-fired power would be further reduced and could in some instances be reversed. To improve on its competitiveness nuclear power will have to continue to control capital costs through replication and reduced construction schedules and to improve plant availability to maximise output

  12. Propagation of high-order circularly polarized Bessel beams and vortex generation in uniaxial crystals

    CSIR Research Space (South Africa)

    Belyi, VN

    2011-05-01

    Full Text Available The authors investigate the generation and transformation of Bessel beams through linear and nonlinear optical crystals. They outline the generation of high-order vortices due to propagation of Bessel beams along the optical axis of uniaxial...

  13. Liquid-Crystal Thermosets, a New Generation of High-Performance Liquid-Crystal Polymers

    Science.gov (United States)

    Dingemans, Theo; Weiser, Erik; Hou, Tan; Jensen, Brian; St. Clair, Terry

    2004-01-01

    One of the major challenges for NASA's next-generation reusable-launch-vehicle (RLV) program is the design of a cryogenic lightweight composite fuel tank. Potential matrix resin systems need to exhibit a low coefficient of thermal expansion (CTE), good mechanical strength, and excellent barrier properties at cryogenic temperatures under load. In addition, the resin system needs to be processable by a variety of non-autoclavable techniques, such as vacuum-bag curing, resin-transfer molding (RTM), vacuum-assisted resin-transfer molding (VaRTM), resin-film infusion (RFI), pultrusion, and advanced tow placement (ATP). To meet these requirements, the Advanced Materials and Processing Branch (AMPB) at NASA Langley Research Center developed a new family of wholly aromatic liquid-crystal oligomers that can be processed and thermally cross-linked while maintaining their liquid-crystal order. All the monomers were polymerized in the presence of a cross-linkable unit by use of an environmentally benign melt-condensation technique. This method does not require hazardous solvents, and the only side product is acetic acid. The final product can be obtained as a powder or granulate and has an infinite shelf life. The obtained oligomers melt into a nematic phase and do not exhibit isotropization temperatures greater than the temperatures of decomposition (Ti > T(sub dec)). Three aromatic formulations were designed and tested and included esters, ester-amides, and ester-imides. One of the major advantages of this invention, named LaRC-LCR or Langley Research Center-Liquid Crystal Resin, is the ability to control a variety of resin characteristics, such as melting temperature, viscosity, and the cross-link density of the final part. Depending on the formulation, oligomers can be prepared with melt viscosities in the range of 10-10,000 poise (100 rad/s), which can easily be melt-processed using a variety of composite-processing techniques. This capability provides NASA with custom

  14. Concept for power scaling second harmonic generation using a cascade of nonlinear crystals

    DEFF Research Database (Denmark)

    Hansen, Anders Kragh; Tawfieq, Mahmoud; Jensen, Ole Bjarlin

    2015-01-01

    for efficient power scaling of single-pass SHG beyond such limits using a cascade of nonlinear crystals, in which the first crystal is chosen for high nonlinear efficiency and the subsequent crystal(s) are chosen for power handling ability. Using this highly efficient singlepass concept, we generate 3.7 W...... successfully combines the high efficiency of the first stage with the good power handling properties of the subsequent stages. The concept is generally applicable and can be expanded with more stages to obtain even higher efficiency, and extends also to other combinations of nonlinear media suitable for other......Within the field of high-power second harmonic generation (SHG), power scaling is often hindered by adverse crystal effects such as thermal dephasing arising from the second harmonic (SH) light, which imposes limits on the power that can be generated in many crystals. Here we demonstrate a concept...

  15. International examples of steam generator replacement

    International Nuclear Information System (INIS)

    Wiechmann, K.

    1993-01-01

    Since 1979-1980 a total of twelve nuclear power plants world-wide have had their steam generators replaced. The replacement of the Combustion steam generators in the Millstone-2 plant in the United States was completed very recently. Steam generator replacement activities are going on at present in four plants. In North Anna, the steam generators have been under replacement since January 1990. In Japan, preparations have been started for Genkai-1. Since January 1992, the two projects in Beznau-1, Switzerland, and Doel-3, Belgium, have bee planned and executed in parallel. Why steam generator replacement? There are a number of defect mechanisms which give rise to the need for early steam generator replacement. One of the main reasons is the use of Inconel-600 as material for the heating tubes. Steam generator heating tubes made of Inconel-600 have been known to exhibit their first defects due to stress corrosion cracking after less than one year of operation. (orig.) [de

  16. Tapered photonic crystal fibers for blue-enhanced supercontinuum generation

    DEFF Research Database (Denmark)

    Møller, Uffe; Sørensen, Simon Toft; Larsen, Casper

    2012-01-01

    Tapering of photonic crystal fibers is an effective way of shifting the blue edge of a supercontinuum spectrum down in the deep-blue. We discuss the optimum taper profile for enhancing the power in the blue edge....

  17. Single-Cycle Terahertz Pulse Generation from OH1 Crystal via Cherenkov Phase Matching

    Science.gov (United States)

    Uchida, Hirohisa; Oota, Kengo; Okimura, Koutarou; Kawase, Kodo; Takeya, Kei

    2018-06-01

    OH1 crystal is an organic nonlinear optical crystal with a large nonlinear optical constant. However, it has dispersion of refractive indices in the terahertz (THz) frequency. This limits the frequencies that satisfy the phase matching conditions for THz wave generation. In this study, we addressed the phase matching conditions for THz wave generation by combining an OH1 crystal with prism-coupled Cherenkov phase matching. We observed the generation of single-cycle THz pulses with a spectrum covering a frequency range of 3 THz. These results prove that combining prism-coupled Cherenkov phase matching with nonlinear optical crystals yields a THz wave generation method that is insusceptible to crystal dispersion.

  18. Equilibrium Kinetics Studies and Crystallization Aboard the International Space Station (ISS) Using the Protein Crystallization Apparatus for Microgravity (PCAM)

    Science.gov (United States)

    Achari, Aniruddha; Roeber, Dana F.; Barnes, Cindy L.; Kundrot, Craig E.; Stinson, Thomas N. (Technical Monitor)

    2002-01-01

    Protein Crystallization Apparatus in Microgravity (PCAM) trays have been used in Shuttle missions to crystallize proteins in a microgravity environment. The crystallization experiments are 'sitting drops' similar to that in Cryschem trays, but the reservoir solution is soaked in a wick. From early 2001, crystallization experiments are conducted on the International Space Station using mission durations of months rather than two weeks on previous shuttle missions. Experiments were set up in April 2001 on Flight 6A to characterize the time crystallization experiments will take to reach equilibrium in a microgravity environment using salts, polyethylene glycols and an organic solvent as precipitants. The experiments were set up to gather data for a series of days of activation with different droplet volumes and precipitants. The experimental set up on ISS and results of this study will be presented. These results will help future users of PCAM to choose precipitants to optimize crystallization conditions for their target macromolecules for a particular mission with known mission duration. Changes in crystal morphology and size between the ground and space grown crystals of a protein and a protein -DNA complex flown on the same mission will also be presented.

  19. Towards protein-crystal centering using second-harmonic generation (SHG) microscopy

    International Nuclear Information System (INIS)

    Kissick, David J.; Dettmar, Christopher M.; Becker, Michael; Mulichak, Anne M.; Cherezov, Vadim; Ginell, Stephan L.; Battaile, Kevin P.; Keefe, Lisa J.; Fischetti, Robert F.; Simpson, Garth J.

    2013-01-01

    The potential of second-harmonic generation (SHG) microscopy for automated crystal centering to guide synchrotron X-ray diffraction of protein crystals has been explored. The potential of second-harmonic generation (SHG) microscopy for automated crystal centering to guide synchrotron X-ray diffraction of protein crystals was explored. These studies included (i) comparison of microcrystal positions in cryoloops as determined by SHG imaging and by X-ray diffraction rastering and (ii) X-ray structure determinations of selected proteins to investigate the potential for laser-induced damage from SHG imaging. In studies using β 2 adrenergic receptor membrane-protein crystals prepared in lipidic mesophase, the crystal locations identified by SHG images obtained in transmission mode were found to correlate well with the crystal locations identified by raster scanning using an X-ray minibeam. SHG imaging was found to provide about 2 µm spatial resolution and shorter image-acquisition times. The general insensitivity of SHG images to optical scatter enabled the reliable identification of microcrystals within opaque cryocooled lipidic mesophases that were not identified by conventional bright-field imaging. The potential impact of extended exposure of protein crystals to five times a typical imaging dose from an ultrafast laser source was also assessed. Measurements of myoglobin and thaumatin crystals resulted in no statistically significant differences between structures obtained from diffraction data acquired from exposed and unexposed regions of single crystals. Practical constraints for integrating SHG imaging into an active beamline for routine automated crystal centering are discussed

  20. International Geomagnetic Reference Field: the 12th generation

    DEFF Research Database (Denmark)

    Thébault, Erwan; Finlay, Chris; Beggan, Ciarán D.

    2015-01-01

    The 12th generation of the International Geomagnetic Reference Field (IGRF) was adopted in December 2014 by the Working Group V-MOD appointed by the International Association of Geomagnetism and Aeronomy (IAGA). It updates the previous IGRF generation with a definitive main field model for epoch ...

  1. Prism-coupled Cherenkov phase-matched terahertz wave generation using a DAST crystal.

    Science.gov (United States)

    Suizu, Koji; Shibuya, Takayuki; Uchida, Hirohisa; Kawase, Kodo

    2010-02-15

    Terahertz (THz) wave generation based on nonlinear frequency conversion is a promising method for realizing a tunable monochromatic high-power THz-wave source. Unfortunately, many nonlinear crystals have strong absorption in the THz frequency region. This limits efficient and widely tunable THz-wave generation. The Cherenkov phase-matching method is one of the most promising techniques for overcoming these problems. Here, we propose a prism-coupled Cherenkov phase-matching (PCC-PM) method, in which a prism with a suitable refractive index at THz frequencies is coupled to a nonlinear crystal. This has the following advantages. Many crystals can be used as THz-wave emitters; the phase-matching condition inside the crystal does not have to be observed; the absorption of the crystal does not prevent efficient generation of radiation; and pump sources with arbitrary wavelengths can be employed. Here we demonstrate PCC-PM THz-wave generation using the organic crystal 4-dimethylamino-N-metyl-4-stilbazolium tosylate (DAST) and a Si prism coupler. We obtain THz-wave radiation with tunability of approximately 0.1 to 10 THz and with no deep absorption features resulting from the absorption spectrum of the crystal. The obtained spectra did not depend on the pump wavelength in the range 1300 to 1450 nm. This simple technique shows promise for generating THz radiation using a wide variety of nonlinear crystals.

  2. PREFACE: 6th International Conference on Aperiodic Crystals (APERIODIC'09)

    Science.gov (United States)

    Grimm, Uwe; McGrath, Rónán; Degtyareva, Olga; Sharma, Hem Raj

    2010-04-01

    Aperiodic Logo Aperiodic'09, the sixth International Conference on Aperiodic Crystals, took place in Liverpool 13-18 September 2009. It was the first major conference in this interdisciplinary research field held in the UK. The conference, which was organised under the auspices of the Commission on Aperiodic Crystals of the International Union of Crystallography (IUCr), followed on from Aperiodic'94 (Les Diablerets, Switzerland), Aperiodic'97 (Alpe d'Huez, France), Aperiodic'2000 (Nijmegen, The Netherlands), Aperiodic'03 (Belo Horizonte, Brazil) and Aperiodic'06 (Zao, Japan). The next conference in the series will take place in Australia in 2012. The Aperiodic conference series is itself the successor to a series of Conferences on Modulated Structures, Polytypes and Quasicrystals (MOSPOQ), which were held in Marseilles (France) in 1984, Wroclaw (Poland) in 1986, Varanasi (India) in 1988 and Balatonszeplak (Hungary) in 1991. The remit of the conference covers two broad areas of research on aperiodic crystals, incommensurately modulated and composite crystals on the one hand, and quasicrystals on the other hand, sharing the property that they are aperiodically ordered solids. In addition, the conference also featured recent research on complex metal alloys, which are in fact periodically ordered solids. However, the term complex refers to their large unit cells, which may contain thousands of atoms, and as a consequence complex metal alloys share some of the properties of quasicrystalline solids. Aperiodic'09 attracted about 110 participants from across the world, including 20 UK-based scientists (the second largest group after Japan who sent 21 delegates). A particular feature of the conference series is its interdisciplinary character, and once again the range of disciplines of participants included mathematics, physics, crystallography and materials science. The programme started with three tutorial lectures on Sunday afternoon, presenting introductory overviews

  3. Internal current generation in respiration chambers

    Science.gov (United States)

    Saborowski, R.; Buchholz, F.

    1998-06-01

    A technical device generating a constant and directed current within a sealed respiration chamber is described. It does not involve any external pumps or tubing. This system is easy to handle, and improved the maintenance of rheotactic pelagic species like the Northern krill ( Meganyctiphanes norvegica, Crustacea) or small fishes ( Gasterosteus aculeatus) under experimental conditions.

  4. The international cooperation for 4. generation systems

    International Nuclear Information System (INIS)

    Bouchard, J.

    2007-01-01

    This series of slides begins with a likely scenario for the demand of nuclear power in 2050: 3.2 Gtep compared to the 0.7 Gtep of today. The demand could be even bigger if more constraints were appearing on the use of fossil energies. Today's industrial offer of nuclear reactors is based on second and third generation design of reactors but sustainable development implies to close the fuel cycle to spare uranium resource and to minimize the volume of high-level radioactive wastes produced so a new generation of reactors is required. 6 concepts have been selected for the fourth generation of reactors. 1) VHTR (Very High Temperature Reactors) for the production of hydrogen. The countries interested in VHTR are: EURATOM countries, France, the Usa, Japan, Switzerland and South-Korea. 2) SFR (Sodium cooled Fast Reactors), the countries interested in SFR are: EURATOM countries, France, Japan, the Usa and South-Korea. 3) LFR (Lead or Bismuth/Lead cooled Fast Reactors), the LFR steering committee is composed of Switzerland, Japan, the Usa and South-Korea. 4) GFR (Gas cooled Fast Reactors), the countries interested in GFR are EURATOM countries, France, Japan and Switzerland. 5) SCWR (Super-Critical Water cooled Reactors), the countries interested in this concept are Canada, EURATOM countries and Japan. 6) MSR (Molten Salt Reactors), the MSR steering committee is composed of France, EURATOM countries and the Usa. Other countries like Argentina, Brazil and United-Kingdom have shown interest in the VHTR concept but have lacked willingness till now to take part into the program. (A.C.)

  5. Optimization of Tapered Photonic Crystal Fibers for Blue-Enhanced Supercontinuum Generation

    DEFF Research Database (Denmark)

    Møller, Uffe; Sørensen, Simon Toft; Larsen, Casper

    2012-01-01

    Tapering of photonic crystal fibers is an effective way of shifting the dispersive wavelength edge of a supercontinuum spectrum down in the deep-blue. We discuss the optimum taper profile for blue-enhanced supercontinuum generation....

  6. Picosecond anti-Stokes generation in a photonic-crystal fiber for interferometric CARS microscopy

    DEFF Research Database (Denmark)

    Keiding, Søren Rud

    2006-01-01

    We generate tunable picosecond anti-Stokes pulses by four-wave mixing of two picosecond pump and Stokes pulse trains in a photonic-crystal fiber. The visible, spectrally narrow anti-Stokes pulses with shifts over 150 nm are generated without generating other spectral features. As a demonstration,...

  7. ICCG-10: Tenth International Conference on Crystal Growth. Poster presentation abstracts

    Science.gov (United States)

    1992-01-01

    Poster presentation abstracts from the tenth International Conference on Crystal Growth (ICCG) (Aug. 16-21, 1992) are provided. Topics discussed at the conference include crystal growth mechanisms, superconductors, semiconductors, laser materials, optical materials, and biomaterials. Organizing committees, ICCG advisory board and officers, and sponsors of the conference are also included.

  8. Efficient femtosecond mid-infrared pulse generation by dispersivewave radiation in bulk lithium niobate crystal

    DEFF Research Database (Denmark)

    Zhou, Binbin; Guo, Hairun; Bache, Morten

    2014-01-01

    We experimentally demonstrate efficient mid-infrared pulse generation by dispersive wave radiation in bulk lithium niobate crystal. Femtosecond mid-IR pulses centering from 2.8–2.92 µm are generated using the single pump wavelengths from 1.25–1.45 µm.......We experimentally demonstrate efficient mid-infrared pulse generation by dispersive wave radiation in bulk lithium niobate crystal. Femtosecond mid-IR pulses centering from 2.8–2.92 µm are generated using the single pump wavelengths from 1.25–1.45 µm....

  9. Highly efficient single-pass sum frequency generation by cascaded nonlinear crystals

    DEFF Research Database (Denmark)

    Hansen, Anders Kragh; Andersen, Peter E.; Jensen, Ole Bjarlin

    2015-01-01

    , despite differences in the phase relations of the involved fields. An unprecedented 5.5 W of continuous-wave diffraction-limited green light is generated from the single-pass sum frequency mixing of two diode lasers in two periodically poled nonlinear crystals (conversion efficiency 50%). The technique......The cascading of nonlinear crystals has been established as a simple method to greatly increase the conversion efficiency of single-pass second-harmonic generation compared to a single-crystal scheme. Here, we show for the first time that the technique can be extended to sum frequency generation...... is generally applicable and can be applied to any combination of fundamental wavelengths and nonlinear crystals....

  10. Towards protein-crystal centering using second-harmonic generation (SHG) microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kissick, David J.; Dettmar, Christopher M. [Purdue University, West Lafayette, IN 47907 (United States); Becker, Michael [Argonne National Laboratory, Argonne, IL 60439 (United States); Mulichak, Anne M. [Hauptman–Woodward Medical Research Institute, Argonne, IL 60439 (United States); Cherezov, Vadim [The Scripps Research Institute, La Jolla, CA 92037 (United States); Ginell, Stephan L. [Argonne National Laboratory, Argonne, IL 60439 (United States); Battaile, Kevin P.; Keefe, Lisa J. [Hauptman–Woodward Medical Research Institute, Argonne, IL 60439 (United States); Fischetti, Robert F. [Argonne National Laboratory, Argonne, IL 60439 (United States); Simpson, Garth J., E-mail: gsimpson@purdue.edu [Purdue University, West Lafayette, IN 47907 (United States)

    2013-05-01

    The potential of second-harmonic generation (SHG) microscopy for automated crystal centering to guide synchrotron X-ray diffraction of protein crystals has been explored. The potential of second-harmonic generation (SHG) microscopy for automated crystal centering to guide synchrotron X-ray diffraction of protein crystals was explored. These studies included (i) comparison of microcrystal positions in cryoloops as determined by SHG imaging and by X-ray diffraction rastering and (ii) X-ray structure determinations of selected proteins to investigate the potential for laser-induced damage from SHG imaging. In studies using β{sub 2} adrenergic receptor membrane-protein crystals prepared in lipidic mesophase, the crystal locations identified by SHG images obtained in transmission mode were found to correlate well with the crystal locations identified by raster scanning using an X-ray minibeam. SHG imaging was found to provide about 2 µm spatial resolution and shorter image-acquisition times. The general insensitivity of SHG images to optical scatter enabled the reliable identification of microcrystals within opaque cryocooled lipidic mesophases that were not identified by conventional bright-field imaging. The potential impact of extended exposure of protein crystals to five times a typical imaging dose from an ultrafast laser source was also assessed. Measurements of myoglobin and thaumatin crystals resulted in no statistically significant differences between structures obtained from diffraction data acquired from exposed and unexposed regions of single crystals. Practical constraints for integrating SHG imaging into an active beamline for routine automated crystal centering are discussed.

  11. International Geomagnetic Reference Field: the 12th generation

    OpenAIRE

    Thébault , Erwan; Finlay , Christopher ,; Beggan , Ciarán ,; Alken , Patrick; Aubert , Julien ,; Barrois , Olivier; Bertrand , François; Bondar , Tatiana; Boness , Axel; Brocco , Laura; Canet , Elisabeth ,; Chambodut , Aude; Chulliat , Arnaud ,; Coïsson , Pierdavide ,; Civet , François

    2015-01-01

    International audience; The 12th generation of the International Geomagnetic Reference Field (IGRF) was adopted in December 2014 by the Working Group V-MOD appointed by the International Association of Geomagnetism and Aeronomy (IAGA). It updates the previous IGRF generation with a definitive main field model for epoch 2010.0, a main field model for epoch 2015.0, and a linear annual predictive secular variation model for 2015.0-2020.0. Here, we present the equations defining the IGRF model, p...

  12. The optimization of longitudinal convective fins with internal heat generation

    International Nuclear Information System (INIS)

    Razelos, P.

    1979-01-01

    The solution of the optimization problem for longitudinal convective fins of constant thickness, triangular or parabolic profile, and uniform internal heat generation, is presented. The cases considered are those of a given heat generation density, total heat generation and heat generation per unit width of the fin, when either the heat dissipation or the width of the fin is prescribed. The results are set forth in a nondimensional form, which are presented graphically. The effect of the fin's thermal conductivity upon the optimum dimensions is discussed, and limiting values for the heat generation and the heat dissipation, which may be imposed on the fin for a feasible optimization, are also obtained. (Auth.)

  13. Measurement of probability distributions for internal stresses in dislocated crystals

    Energy Technology Data Exchange (ETDEWEB)

    Wilkinson, Angus J.; Tarleton, Edmund; Vilalta-Clemente, Arantxa; Collins, David M. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Jiang, Jun; Britton, T. Benjamin [Department of Materials, Imperial College London, Royal School of Mines, Exhibition Road, London SW7 2AZ (United Kingdom)

    2014-11-03

    Here, we analyse residual stress distributions obtained from various crystal systems using high resolution electron backscatter diffraction (EBSD) measurements. Histograms showing stress probability distributions exhibit tails extending to very high stress levels. We demonstrate that these extreme stress values are consistent with the functional form that should be expected for dislocated crystals. Analysis initially developed by Groma and co-workers for X-ray line profile analysis and based on the so-called “restricted second moment of the probability distribution” can be used to estimate the total dislocation density. The generality of the results are illustrated by application to three quite different systems, namely, face centred cubic Cu deformed in uniaxial tension, a body centred cubic steel deformed to larger strain by cold rolling, and hexagonal InAlN layers grown on misfitting sapphire and silicon carbide substrates.

  14. Generation of sub-100-fs Stokes pulses upon SRS in a barium nitrate crystal

    International Nuclear Information System (INIS)

    Konyashchenko, Aleksandr V; Losev, Leonid L; Tenyakov, S Yu

    2010-01-01

    72-fs pulses are generated at the first Stokes component frequency upon stimulated Raman scattering in a barium nitrate crystal for the radiation of the Ti 3+ :Al 2 O 3 laser with the pulse duration of 50 fs. The energy efficiency of conversion is 20%. The barium nitrate crystal was optically pumped by two consecutive orthogonally polarised chirped pulses with the following time compression of the Stokes radiation pulse. (nonlinear optical phenomena)

  15. Process gas generator feeding internal combustion piston engines

    Energy Technology Data Exchange (ETDEWEB)

    Iwantscheff, G; Kostka, H; Henkel, H J

    1978-10-26

    The invention relates to a process gas generator feeding gaseous fuel to internal combustion piston engines. The cylinder linings of the internal combustion engine are enclosed by the catalytic reaction chamber of the process gas generator which contains perforated sintered nozzle bricks as carriers of the catalysts needed for the conversion. The reaction chamber is surrounded by the exhaust gas chamber around which a tube coil is ound which feeds the fuel charge to the reaction chamber after evaporation and mixing with exhaust gas and air. The fuel which may be used for this purpose, e.g., is low-octane gasoline or diesel fuel. In the reaction chamber the fuel is catalytically converted at temperatures above 200/sup 0/C, e.g., into low-molecular paraffins, carbon monoxide and hydrogen. Operation of the internal combustion engine with a process gas generator greatly reduces the pollutant content of the exhaust gases.

  16. Effect of Li and NH4 doping on the crystal perfection, second harmonic generation efficiency and laser damage threshold of potassium pentaborate crystals

    Science.gov (United States)

    Vigneshwaran, A. N.; Kalainathan, S.; Raja, C. Ramachandra

    2018-03-01

    Potassium pentaborate (KB5) is an excellent nonlinear optical material especially in the UV region. In this work, Li and NH4 doped KB5 crystals were grown using slow evaporation solution growth method. The incorporation of dopant has been confirmed and analysed by Energy dispersive X-ray analysis (EDAX), Inductively coupled plasma (ICP) analysis and Raman spectroscopy. The crystalline perfection of pure and doped KB5 crystals was studied by High resolution X-ray diffraction (HRXRD) analysis. Structural grain boundaries were observed in doped crystals. Second harmonic generation was confirmed for pure and doped crystals and output values revealed the enhancement of SHG efficiency in doped crystals. Resistance against laser damage was carried out using 1064 nm Nd-YAG laser of pulse width 10 ns. The laser damage threshold value is increased in Li doped crystal and decreased in NH4 doped crystal when compared to pure KB5 crystal.

  17. A new generation of 99.999% enriched 28Si single crystals for the determination of Avogadro’s constant

    Science.gov (United States)

    Abrosimov, N. V.; Aref'ev, D. G.; Becker, P.; Bettin, H.; Bulanov, A. D.; Churbanov, M. F.; Filimonov, S. V.; Gavva, V. A.; Godisov, O. N.; Gusev, A. V.; Kotereva, T. V.; Nietzold, D.; Peters, M.; Potapov, A. M.; Pohl, H.-J.; Pramann, A.; Riemann, H.; Scheel, P.-T.; Stosch, R.; Wundrack, S.; Zakel, S.

    2017-08-01

    A metrological challenge is currently underway to replace the present definition of the kilogram. One prerequisite for this is that the Avogadro constant, N A, which defines the number of atoms in a mole, needs to be determined with a relative uncertainty of better than 2  ×  10-8. The method applied in this case is based on the x-ray crystal density experiment using silicon crystals. The first attempt, in which silicon of natural isotopic composition was used, failed. The solution chosen subsequently was the usage of silicon highly enriched in 28Si from Russia. First, this paper reviews previous efforts from the very first beginnings to an international collaboration with the goal of producing a 28Si single crystal with a mass of 5 kg, an enrichment greater than 0.9999 and of sufficient chemical purity. Then the paper describes the activities of a follow-up project, conducted by PTB, to produce a new generation of highly enriched silicon in order to demonstrate the quasi-industrial and reliable production of more than 12 kg of the 28Si material with enrichments of five nines. The intention of this project is also to show the availability of 28Si single crystals as a guarantee for the future realisation of the redefined kilogram.

  18. Acoustic methods for high-throughput protein crystal mounting at next-generation macromolecular crystallographic beamlines.

    Science.gov (United States)

    Roessler, Christian G; Kuczewski, Anthony; Stearns, Richard; Ellson, Richard; Olechno, Joseph; Orville, Allen M; Allaire, Marc; Soares, Alexei S; Héroux, Annie

    2013-09-01

    To take full advantage of advanced data collection techniques and high beam flux at next-generation macromolecular crystallography beamlines, rapid and reliable methods will be needed to mount and align many samples per second. One approach is to use an acoustic ejector to eject crystal-containing droplets onto a solid X-ray transparent surface, which can then be positioned and rotated for data collection. Proof-of-concept experiments were conducted at the National Synchrotron Light Source on thermolysin crystals acoustically ejected onto a polyimide `conveyor belt'. Small wedges of data were collected on each crystal, and a complete dataset was assembled from a well diffracting subset of these crystals. Future developments and implementation will focus on achieving ejection and translation of single droplets at a rate of over one hundred per second.

  19. Anisotropic frictional heating and defect generation in cyclotrimethylene-trinitramine molecular crystals

    Science.gov (United States)

    Rajak, Pankaj; Mishra, Ankit; Sheng, Chunyang; Tiwari, Subodh; Kalia, Rajiv K.; Nakano, Aiichiro; Vashishta, Priya

    2018-05-01

    Anisotropic frictional response and corresponding heating in cyclotrimethylene-trinitramine molecular crystals are studied using molecular dynamics simulations. The nature of damage and temperature rise due to frictional forces is monitored along different sliding directions on the primary slip plane, (010), and on non-slip planes, (100) and (001). Correlations between the friction coefficient, deformation, and frictional heating are established. We find that the friction coefficients on slip planes are smaller than those on non-slip planes. In response to sliding on a slip plane, the crystal deforms easily via dislocation generation and shows less heating. On non-slip planes, due to the inability of the crystal to deform via dislocation generation, a large damage zone is formed just below the contact area, accompanied by the change in the molecular ring conformation from chair to boat/half-boat. This in turn leads to a large temperature rise below the contact area.

  20. Structural defect generation in indium antimonide single crystals during electro-erosion cutting

    International Nuclear Information System (INIS)

    Kravetskij, M.Yu.; Matsas, E.P.; Skorokhod, M.Ya.; Fomin, A.V.; Khromyak, K.Ya.

    1990-01-01

    Using X-ray topography structural defects generating during electro-erosion cutting of InSb single crystals are studied. It is shown that dislocations, are introduced into so cut dislocation-free ingot plates, nucleation centers being located on their surfaces. It is detected that foreign phase inclusions in InSb are efficient sources of dislocations during cutting

  1. Flat super-continuum generation based on normal dispersion nonlinear photonic crystal fibre

    DEFF Research Database (Denmark)

    Chow, K.K.; Takushima, Y.; Lin, C.

    2006-01-01

    Flat super-continuum generation spanning over the whole telecommunication band using a passively modelocked fibre laser source at 1550 nm together with a dispersion-flattened nonlinear photoinc crystal fibre is demonstrated. Since the pulses propagate in the normal dispersion regime of the fibre...

  2. A structure and second-harmonic generation of crystals Li B3O5

    International Nuclear Information System (INIS)

    Burak, Ya.V.

    1997-01-01

    Projections of atoms of nonlinear optical crystals Li B 3 O 5 onto planes perpendicular to directions of the phase matching of type-1 and type-2 for second-harmonic generation (SHG) in a YAG:Nd laser are constructed. Analyses of the interdependence of orientations of (B 3 O 7 ) 5 -complexes and of the effectiveness of SHG are conducted

  3. Outlook of nuclear power generation and international situation

    Energy Technology Data Exchange (ETDEWEB)

    Ekulund, S [International Atomic Energy Agency, Vienna (Austria)

    1978-01-01

    Nuclear power generation is advancing at rapid rate over the world, without any major accident. For the base load of electric power, when choice is made between nuclear energy and petroleum, Nuclear energy has larger economic advantages over petroleum as compared with the days before the oil crisis. The costs of its fuel and fuel cycle technology are reasonable. However, nuclear power generation currently has a number of problems. What causes this uncertainty is not technological, but political, i.e. governmental policy changes, and this is based on the apprehension about nuclear proliferation. What is necessary is to strengthen the existing international framework of nuclear nonproliferation. In this respect, IAEA through comprehensive safeguards will make contributions largely to reduction of the political uncertainty. It is important that the new initiatives toward international nuclear cooperation should eliminate the current trends of restraint and denial.

  4. Systematic Procedure for Generating Operational Policies to Achieve Target Crystal Size Distribution (CSD) in Batch Cooling Crystallization

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli; Singh, Ravendra; Sin, Gürkan

    2011-01-01

    Batch cooling crystallization is one of the important unit operations involving separation of solid-liquid phases. Usually the most common crystal product qualities are directly related to the crystal size distribution (CSD). However the main difficulty in batch crystallization is to obtain a uni...

  5. Study of entropy generation in a slab with non-uniform internal heat generation

    Directory of Open Access Journals (Sweden)

    El Haj Assad Mamdouh

    2013-01-01

    Full Text Available Analysis of entropy generation in a rectangular slab with a nonuniform internal heat generation is presented. Dimensionless local and total entropy generation during steady state heat conduction through the slab are obtained. Two different boundary conditions have been considered in the analysis, the first with asymmetric convection and the second with constant slab surface temperature. Temperature distribution within the slab is obtained analytically. The study investigates the effect of some relevant dimensionless heat transfer parameters on entropy generation. The results show that there exists a minimum local entropy generation but there does not exist a minimum total entropy generation for certain combinations of the heat transfer parameters. The results of calculations are presented graphically.

  6. The International Geomagnetic Reference Field: the twelfth generation

    Science.gov (United States)

    Thebault, Erwan; Finlay, Christopher; The IGRF Working Group

    2015-04-01

    The IGRF is an internationally-agreed reference model of the Earth's magnetic field produced under the auspices of the International Association of Geomagnetism and Aeronomy. The IGRF-12 is the latest update of this well-known model which is used each year by many thousands of users for both industrial and scientific purposes. In October 2014, ten institutions worldwide have made contributions to the IGRF. These models were evaluated and the twelfth generation of the International Geomagnetic Reference Field (IGRF) was adopted in December 2014. In this presentation, we will report on the IGRF activities, briefly describe the candidate models, summarize the evaluation of models performed by different independent teams, show how the IGRF-12 models were calculated and finally discuss some of the main magnetic features of this new model.

  7. International project GT-MHR - New generation of nuclear reactors

    International Nuclear Information System (INIS)

    Vasyaev, A.; Kodochigov, N.; Kuzavkov, N.; Kuznetsov, L.

    2001-01-01

    Gas turbine-modular helium reactor (GT-MHR) is the reactor of new generation, which satisfies the requirements of the progressing large-scale nuclear power engineering. The activities in GT-MHR Project started in 1995. In 1997 the Conceptual Design was developed under four-side Agreement (MINATOM, General Atomics, FRAMATOME, Fuji Electric); it has passed through the internal and international reviews, has been approved and recommended for further development as one of new trends in creation of new generation plants. Starting from 1999, the activities in the development of the Preliminary Design of the plant were deployed under the Agreement between the Government of the United States of America and the Government of the Russian Federation on Scientific and Technical Cooperation in the Management of Plutonium That Has Been Withdrawn From Nuclear Military Programs dated July 24, 1998. The activities are established under the Contract between MINATOM and OKBM Russia, and under the General Agreement between Department of Energy (DOE), USA and OKBM. The GT-MHR Project is included into 'Development Strategy of Russian Nuclear Power in the first Half of the XXI-st Century' providing for 'the participation in an international project on the development and construction of GT-MHR nuclear power plant till year 2010 and 'operation of GT-MHR prototype unit and creation of fuel fabrication facility (within framework of International Project) till year 2030'. (author)

  8. Inside-out: comparing internally generated and externally generated basic emotions.

    Science.gov (United States)

    Salas, Christian E; Radovic, Darinka; Turnbull, Oliver H

    2012-06-01

    A considerable number of mood induction (MI) procedures have been developed to elicit emotion in normal and clinical populations. Although external procedures (e.g., film clips, pictures) are widely used, a number of experiments elicit emotion by using self-generated procedures (e.g., recalling an emotional personal episode). However, no study has directly compared the effectiveness of two types of internal versus external MI across multiple discrete emotions. In the present experiment, 40 undergraduate students watched film clips (external procedure) and recalled personal events (internal procedure) inducing 4 basic emotions (fear, anger, joy, sadness) and later completed a self-report questionnaire. Remarkably, both internal and external procedures elicited target emotions selectively, compared with nontarget emotions. When contrasting the intensity of target emotions, both techniques showed no significant differences, with the exception of Joy, which was more intensely elicited by the internal procedure. Importantly, when considering the overall level of intensity, it was always greater in the internal procedure, for each stimulus. A more detailed investigation of the data suggest that recalling personal events (a type of internal procedure) generates more negative and mixed blends of emotions, which might account for the overall higher intensity of the internal mood induction.

  9. Flat Supercontinuum Generation within the Telecommunication Wave Bands in a Photonic Crystal Fiber with Central Holes

    International Nuclear Information System (INIS)

    Han Ying; Hou Lan-Tian; Zhou Gui-Yao; Xia Chang-Ming; Wang Wei; Wang Chao; Hou Zhi-Yun; Yuan Jin-Hui

    2012-01-01

    Flat supercontinuum in the telecommunication wave bands of E+S+C is generated by coupling a train of femtosecond pulses generated by a mode-locked Ti:sapphire laser into the fundamental mode of a photonic crystal fiber with central holes fabricated in our lab. The pulse experiences the anomalous dispersion regime, and the soliton dynamic effect plays an important role in supercontinuum generation. The output spectrum in the wavelength range of 1360–1565 nm does not include significant ripples due to higher pump peak power, and the normalized intensity shows less fluctuation. (fundamental areas of phenomenology(including applications))

  10. Generation 4 International Forum (GIF). 2015 Annual Report

    International Nuclear Information System (INIS)

    2016-01-01

    This ninth edition of the Generation IV International Forum (GIF) Annual Report highlights the main achievements of the Forum in 2015. On 26 February 2015, the Framework Agreement for International Collaboration on Research and Development of Generation IV Nuclear Energy Systems was extended for another ten years, thereby paving the way for continued collaboration among participating countries. GIF organised the 3. Symposium in Makuhari Messe, Japan in May 2015 to present progress made in the development of the six generation IV systems: the gas-cooled fast reactor, the sodium-cooled fast reactor, the supercritical-water-cooled reactor, the very-high-temperature reactor, the lead-cooled fast reactor and the molten salt reactor. The report gives a detailed description of progress made in the 11 existing project arrangements. It also describes the development of safety design criteria and guidelines for the sodium-cooled fast reactor, in addition to the outcome of GIF engagement with regulators on safety approaches for generation IV systems. (authors)

  11. Work-Related Attitudes of Czech Generation Z: International Comparison

    Directory of Open Access Journals (Sweden)

    Jaroslava Kubátová,

    2016-12-01

    Full Text Available The goal of this article is to present work-related attitudes of a sample of Czech Generation Z and their comparison to the results of an international research study. Currently, there are three important trends influencing the labor market: (1 the origin and development of a ubiquitous working environment, (2 the thriving of coworking centers, and (3 Generation Z's entering the labor market. Instead of traditional jobs, the bearers of human capital tend to choose independent work in an online environment, and often work in coworking centers. Using self-determination theory, we substantiate why they thrive better this way. Based on the results of an international research project focused on work attitudes among Generation Z and the results of a replication study we carried out in the Czech Republic, we attest that members of Generation Z may prefer independent virtual work in coworking centers, too. The total amount of available human capital, the lack of which is pointed out by companies, may grow thanks to new ways of working. Companies, which can use human capital of independent workers, gain a competitive advantage.

  12. Experimental investigation of natural convection induced by internal heat generation

    International Nuclear Information System (INIS)

    Tasaka, Y; Kudoh, Y; Takeda, Y; Yanagisawa, T

    2005-01-01

    Dilatation of a convection cell with respect to its Rayleigh number, one of the problems in internally heated convection, was quantitatively investigated by analyzing temperature field in a cell. The temperature field visualized by a thermo-chromic liquid crystal (TLC) expresses the cell dilatation. A calibration system was developed to convert the visualized photographs of the temperature field to the temperature field. A calibration curve correlating color information extracted from the photograph and temperature was determined from the approximately linear temperature distribution in the horizontal fluid layer using the hue method. Photos taken at various internal Rayleigh numbers were converted to the temperature field by the obtained curve. Extracting individual cells from a temperature field achieves a quantitative expression of the cell dilatation as the variation of the wavenumber of the cell with Rayleigh number increases. The temperature profile in a cell shows that high temperature areas appear at the apexes of the cell, largely different from the profile obtained by linear theory

  13. Variation of low temperature internal friction of microplastic deformation of high purity molybdenum single crystals

    International Nuclear Information System (INIS)

    Pal-Val, P.P.; Kaufmann, H.J.

    1984-01-01

    Amplitude and temperature spectra of ultrasound absorption in weakly deformed high purity molybdenum single crystals of different orientations were measured. The results were discussed in terms of parameter changes related to quasiparticle or dislocation oscillations, respectively, dislocation point defect interactions as well as defect generation at microplastic deformation. (author)

  14. Variation of low temperature internal friction of microplastic deformation of high purity molybdenum single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Pal-Val, P.P. (AN Ukrainskoj SSR, Kharkov. Fiziko-Tekhnicheskij Inst. Nizkikh Temperatur); Kaufmann, H.J. (Akademie der Wissenschaften der DDR, Berlin)

    1984-08-01

    Amplitude and temperature spectra of ultrasound absorption in weakly deformed high purity molybdenum single crystals of different orientations were measured. The results were discussed in terms of parameter changes related to quasiparticle or dislocation oscillations, respectively, dislocation point defect interactions as well as defect generation at microplastic deformation.

  15. Spontaneous generation and reversals of mean flows in a convectively-generated internal gravity wave field

    Science.gov (United States)

    Couston, Louis-Alexandre; Lecoanet, Daniel; Favier, Benjamin; Le Bars, Michael

    2017-11-01

    We investigate via direct numerical simulations the spontaneous generation and reversals of mean zonal flows in a stably-stratified fluid layer lying above a turbulent convective fluid. Contrary to the leading idealized theories of mean flow generation by self-interacting internal waves, the emergence of a mean flow in a convectively-generated internal gravity wave field is not always possible because nonlinear interactions of waves of different frequencies can disrupt the mean flow generation mechanism. Strong mean flows thus emerge when the divergence of the Reynolds stress resulting from the nonlinear interactions of internal waves produces a strong enough anti-diffusive acceleration for the mean flow, which, as we will demonstrate, is the case when the Prandtl number is sufficiently low, or when the energy input into the internal wavefield by the convection and density stratification are sufficiently large. Implications for mean zonal flow production as observed in the equatorial stratospheres of the Earth, Saturn and Jupiter, and possibly occurring in other geophysical systems such as planetary and stellar interiors will be briefly discussed. Funding provided by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program through Grant Agreement No. 681835-FLUDYCO-ERC-2015-CoG.

  16. Generation and extinction of crystal nuclei in an extremely non-equilibrium glassy state of salol

    CERN Document Server

    Paladi, F

    2003-01-01

    Strange generation and subsequent extinction of crystal nuclei were observed in the glassy state of salol (phenyl salicylate) during the course of ageing at very low constant-temperatures. The presence/absence of crystal nuclei within the glass were judged, by using a differential scanning calorimeter (DSC), from whether the crystal growth and fusion phenomena were observed in the following heating process or not. The liquid sample was cooled rapidly at 200 K min sup - sup 1 from 333 K above the fusion temperature down to a desired ageing temperature (T sub a) below the glass transition temperature (T sub g = 220 K), aged there for different periods (t sub a), and then heated up to 213 K at 200 K min sup - sup 1. The DSC measurement was carried out at 10 K min sup - sup 1 from 213 to 333 K. The ageing periods were taken in a range between 30 s and 316 min. At T sub a = 213 K, crystal nucleation was found to proceed for ageing longer than 100 min. No crystal nucleation was found at T sub a in between 123 and 1...

  17. Elucidation of Compression-Induced Surface Crystallization in Amorphous Tablets Using Sum Frequency Generation (SFG) Microscopy.

    Science.gov (United States)

    Mah, Pei T; Novakovic, Dunja; Saarinen, Jukka; Van Landeghem, Stijn; Peltonen, Leena; Laaksonen, Timo; Isomäki, Antti; Strachan, Clare J

    2017-05-01

    To investigate the effect of compression on the crystallization behavior in amorphous tablets using sum frequency generation (SFG) microscopy imaging and more established analytical methods. Tablets containing neat amorphous griseofulvin with/without excipients (silica, hydroxypropyl methylcellulose acetate succinate (HPMCAS), microcrystalline cellulose (MCC) and polyethylene glycol (PEG)) were prepared. They were analyzed upon preparation and storage using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM) and SFG microscopy. Compression-induced crystallization occurred predominantly on the surface of the neat amorphous griseofulvin tablets, with minimal crystallinity being detected in the core of the tablets. The presence of various types of excipients was not able to mitigate the compression-induced surface crystallization of the amorphous griseofulvin tablets. However, the excipients affected the crystallization rate of amorphous griseofulvin in the core of the tablet upon compression and storage. SFG microscopy can be used in combination with ATR-FTIR spectroscopy and SEM to understand the crystallization behaviour of amorphous tablets upon compression and storage. When selecting excipients for amorphous formulations, it is important to consider the effect of the excipients on the physical stability of the amorphous formulations.

  18. Quickly Getting the Best Data from Your Macromolecular Crystals with a New Generation of Beamline Instruments

    International Nuclear Information System (INIS)

    Cipriani, Florent; Felisaz, Franck; Lavault, Bernard; Brockhauser, Sandor; Ravelli, Raimond; Launer, Ludovic; Leonard, Gordon; Renier, Michel

    2007-01-01

    While routine Macromolecular x-ray (MX) crystallography has relied on well established techniques for some years all the synchrotrons around the world are improving the throughput of their MX beamlines. Third generation synchrotrons provide small intense beams that make data collection of 5-10 microns sized crystals possible. The EMBL/ESRF MX Group in Grenoble has developed a new generation of instruments to easily collect data on 10 μm size crystals in an automated environment. This work is part of the Grenoble automation program that enables FedEx like crystallography using fully automated data collection and web monitored experiments. Seven ESRF beamlines and the MRC BM14 ESRF/CRG beamline are currently equipped with these latest instruments. We describe here the main features of the MD2x diffractometer family and the SC3 sample changer robot. Although the SC3 was primarily designed to increase the throughput of MX beamlines, it has also been shown to be efficient in improving the quality of the data collected. Strategies in screening a large number of crystals, selecting the best, and collecting a full data set from several re-oriented micro-crystals can now be run with minimum time and effort. The MD2x and SC3 instruments are now commercialised by the company ACCEL GmbH

  19. Effect of Sr2+ concentration on generation of colour centres in KCl crystals

    International Nuclear Information System (INIS)

    Kowalczyk, J.; Damm, J.Z.

    1976-01-01

    Gamma radiation induced generation of F- and V-type colour centres in KCl crystals (one pure and eight Sr-doped) is examined. Beginning with about 66 ppm Sr in the sample the late colouration stage is practically suppressed. It is shown that V 2 bands are characteristic for the initial colouration stage and V 3 band for the late colouration stage. The latter band appears in the pure or low-doped KCl and in plastically deformed high-doped KCl. The introduction of fresh dislocation into the crystal either by irradiation (low-doped KCl) or by plastic deformation (high-doped KCl) is responsible for the disappearance of primary cation vacancies. Some additional data concerning the dose-rate effect and generation of F 2 (M) centres are presented. (author)

  20. The effect of internal and external stress on two-way shape-memory behaviour in Co49Ni21.6Ga29.4 single crystals

    International Nuclear Information System (INIS)

    Liu, G D; Dai, X F; Luo, H Z; Liu, H Y; Meng, F B; Li, Y; Yu, X; Chen, J L; Wu, G H

    2011-01-01

    The effect of the internal stress on the two-way shape memory in Co 49 Ni 21.6 Ga 29.4 single crystals has been investigated. We found that the internal stress generated natively by the solidifying process works as a tensile force along the growth direction. Applying different compressive pre-stresses along the [0 0 1] direction, the shape-memory strain can be continuously changed from +1.0% to -2.3%. In the [1 1 0] direction, the strain monotonically increases from -2.0% to -4.0% due to a strong detwinning produced by the consistent effect of the external and internal stresses.

  1. Internal oxidation as a mechanism for steam generator tube degradation

    Energy Technology Data Exchange (ETDEWEB)

    Gendron, T.S. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Scott, P.M. [Framatome, Paris (France); Bruemmer, S.M. [Pacific Northwest National Laboratory, Richland, WA (United States); Thomas, L.E. [Washington State Univ., School of Mechanical and Materials Engineering, Pullman, WA (United States)

    1999-12-01

    Internal oxidation has been proposed as a plausible mechanism for intergranular stress-corrosion cracking (IGSCC) of alloy 600 steam generator tubing. This theory can reconcile the main thermodynamic and kinetic characteristics of the observed cracking in hydrogenated primary water. Although secondary-side IG attack or IGSCC is commonly attributed to the presence of strong, caustic or acidic solutions, more recent evidence suggests that this degradation takes place in a near neutral environment, possibly dry polluted steam. As a result, internal oxidation is also a feasible mechanism for secondary side degradation. The present paper reviews experimental work conducted in an attempt to determine the validity of this mechanism. The consequences for the expected behaviour of alloys 690 and 800 replacement materials are also described. (author)

  2. Internal oxidation as a mechanism for steam generator tube degradation

    Energy Technology Data Exchange (ETDEWEB)

    Gendron, T.S. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Scott, P.M. [Framatome, Paris (France); Bruemmer, S.M. [Pacific Northwest National Lab., Richland, Washington (United States); Thomas, L.E. [Washington State Univ., School of Mechanical and Materials Engineering, Pullman, WA (United States)

    1998-07-01

    Internal oxidation has been proposed as a plausible mechanism for intergranular stress corrosion cracking (IGSCC) of alloy 600 steam generator tubing. This theory can reconcile the main thermodynamic and kinetic characteristics of the observed cracking in hydrogenated primary water. Although secondary side IG attack or IGSCC is commonly attributed to the presence of strong caustic or acidic solutions, more recent evidence suggests that this degradation takes place in a near-neutral environment, possibly dry polluted steam. As a result, internal oxidation is also a feasible mechanism for secondary side degradation. The present paper reviews experimental work carried out in an attempt to determine the validity of this mechanism. The consequences for the expected behaviour of alloys 690 and 800 replacement materials are also described. (author)

  3. Review on Korea Participation of Generation IV International Forum (GIF)

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jewhan; Jeong, Ji-Young; Hahn, Dohee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Generation IV International Forum (GIF) originates from US proposal of an initiative in 2000. The vision was to leapfrog LWR technology and collaborate with international partners to share R and D on advanced nuclear systems. Nine countries and EU joined the initiative and Gen IV concept was defined via technology goals and legal framework. Two years study with more than 100 experts worldwide has evaluated nearly 100 reactor designs and down selected six most promising concepts. In 2005, the first signatures on Framework Agreement were collected and the first research projects were defined in 2006. Korea is one of the founding members of GIF and actively participating in various areas. In 2013, TD was assigned to Korean expert and Korea is endeavoring to enhance the benefit of participation since this turning point. In this paper, pros and cons of engaging with GIF were briefly introduced and items to maximize the benefit were suggested.

  4. Review on Korea Participation of Generation IV International Forum (GIF)

    International Nuclear Information System (INIS)

    Lee, Jewhan; Jeong, Ji-Young; Hahn, Dohee

    2015-01-01

    Generation IV International Forum (GIF) originates from US proposal of an initiative in 2000. The vision was to leapfrog LWR technology and collaborate with international partners to share R and D on advanced nuclear systems. Nine countries and EU joined the initiative and Gen IV concept was defined via technology goals and legal framework. Two years study with more than 100 experts worldwide has evaluated nearly 100 reactor designs and down selected six most promising concepts. In 2005, the first signatures on Framework Agreement were collected and the first research projects were defined in 2006. Korea is one of the founding members of GIF and actively participating in various areas. In 2013, TD was assigned to Korean expert and Korea is endeavoring to enhance the benefit of participation since this turning point. In this paper, pros and cons of engaging with GIF were briefly introduced and items to maximize the benefit were suggested

  5. Internal oxidation as a mechanism for steam generator tube degradation

    International Nuclear Information System (INIS)

    Gendron, T.S.; Scott, P.M.; Bruemmer, S.M.; Thomas, L.E.

    1998-01-01

    Internal oxidation has been proposed as a plausible mechanism for intergranular stress corrosion cracking (IGSCC) of alloy 600 steam generator tubing. This theory can reconcile the main thermodynamic and kinetic characteristics of the observed cracking in hydrogenated primary water. Although secondary side IG attack or IGSCC is commonly attributed to the presence of strong caustic or acidic solutions, more recent evidence suggests that this degradation takes place in a near-neutral environment, possibly dry polluted steam. As a result, internal oxidation is also a feasible mechanism for secondary side degradation. The present paper reviews experimental work carried out in an attempt to determine the validity of this mechanism. The consequences for the expected behaviour of alloys 690 and 800 replacement materials are also described. (author)

  6. Photonic crystal fibers for supercontinuum generation pumped by a gain-switched CW fiber laser

    DEFF Research Database (Denmark)

    Larsen, Casper; Noordegraaf, Danny; Hansen, Kim P.

    2012-01-01

    Supercontinuum generation in photonics crystal fibers (PCFs) pumped by CW lasers yields high spectral power density and average power. However, such systems require very high pump power and long nonlinear fibers. By on/off modulating the pump diodes of the fiber laser, the relaxation oscillations...... of the laser can be exploited to enhance the broadening process. The physics behind the supercontinuum generation is investigated by sweeping the fiber length, the zero dispersion wavelength, and the fiber nonlinearity. We show that by applying gain-switching a high average output power of up to 30 W can...

  7. Vortex Airy beams directly generated via liquid crystal q-Airy-plates

    Science.gov (United States)

    Wei, Bing-Yan; Liu, Sheng; Chen, Peng; Qi, Shu-Xia; Zhang, Yi; Hu, Wei; Lu, Yan-Qing; Zhao, Jian-Lin

    2018-03-01

    Liquid crystal q-Airy-plates with director distributions integrated by q-plates and polarization Airy masks are proposed and demonstrated via the photoalignment technique. Single/dual vortex Airy beams of opposite topological charges and orthogonal circular polarizations are directly generated with polarization-controllable characteristic. The singular phase of the vortex part is verified by both astigmatic transformation and digital holography. The trajectory of vortex Airy beams is investigated, manifesting separate propagation dynamics of optical vortices and Airy beams. Meanwhile, Airy beams still keep their intrinsic transverse acceleration, self-healing, and nondiffraction features. This work provides a versatile candidate for generating high-quality vortex Airy beams.

  8. Third harmonic frequency generation by type-I critically phase-matched LiB3O5 crystal by means of optically active quartz crystal.

    Science.gov (United States)

    Gapontsev, Valentin P; Tyrtyshnyy, Valentin A; Vershinin, Oleg I; Davydov, Boris L; Oulianov, Dmitri A

    2013-02-11

    We present a method of third harmonic generation at 355 nm by frequency mixing of fundamental and second harmonic radiation of an ytterbium nanosecond pulsed all-fiber laser in a type-I phase-matched LiB(3)O(5) (LBO) crystal where originally orthogonal polarization planes of the fundamental and second harmonic beams are aligned by an optically active quartz crystal. 8 W of ultraviolet light at 355 nm were achieved with 40% conversion efficiency from 1064 nm radiation. The conversion efficiency obtained in a type-I phase-matched LBO THG crystal was 1.6 times higher than the one achieved in a type-II LBO crystal at similar experimental conditions. In comparison to half-wave plates traditionally used for polarization alignment the optically active quartz crystal has much lower temperature dependence and requires simpler optical alignment.

  9. Generating, Separating and Polarizing Terahertz Vortex Beams via Liquid Crystals with Gradient-Rotation Directors

    Directory of Open Access Journals (Sweden)

    Shi-Jun Ge

    2017-10-01

    Full Text Available Liquid crystal (LC is a promising candidate for terahertz (THz devices. Recently, LC has been introduced to generate THz vortex beams. However, the efficiency is intensely dependent on the incident wavelength, and the transformed THz vortex beam is usually mixed with the residual component. Thus, a separating process is indispensable. Here, we introduce a gradient blazed phase, and propose a THz LC forked polarization grating that can simultaneously generate and separate pure THz vortices with opposite circular polarization. The specific LC gradient-rotation directors are implemented by a photoalignment technique. The generated THz vortex beams are characterized with a THz imaging system, verifying features of polarization controllability. This work may pave a practical road towards generating, separating and polarizing THz vortex beams, and may prompt applications in THz communications, sensing and imaging.

  10. Abstracts of 2. international conference C-BN and diamond crystallization under reduced pressure

    International Nuclear Information System (INIS)

    1995-01-01

    The important problem and the last advanced one from the view point of electronic materials sciences is the new A III B V compounds creation and investigation of their properties. This domain was the main subject of the 2. International Conference on C-BN and diamond crystallization under reduced pressure. The conference has been divided into 8 sessions. They were: opening address, c-BN, new materials, posters, diamond, applications, posters

  11. Efficient terahertz wave generation from GaP crystals pumped by chirp-controlled pulses from femtosecond photonic crystal fiber amplifier

    International Nuclear Information System (INIS)

    Li, Jiang; Shi, Junkai; Xu, Baozhong; Xing, Qirong; Wang, Chingyue; Chai, Lu; Liu, Bowen; Hu, Minglie; Li, Yanfeng; Fedotov, Andrey B.; Zheltikov, Aleksei M.

    2014-01-01

    A chirp-tunable femtosecond 10 W, 42 MHz photonic-crystal-fiber oscillator-amplifier system that is capable of delivering sub-60 fs light pulses at 1040 nm is used to demonstrate high-efficiency terahertz radiation generation via optical rectification in GaP crystals only a few millimeters in length. The optimization of the chirp of the fiber-laser pulses is shown to radically enhance the terahertz output, indicating one possible way to more efficiently use these extended nonlinear crystals in compact fiber-pumped terahertz radiation sources

  12. Generation of femtosecond laser pulses at 396 nm in K3B6O10Cl crystal

    International Nuclear Information System (INIS)

    Zhang Ning-Hua; Huang Hang-Dong; Tian Wen-Long; Zhu Jiang-Feng; Teng Hao; Fang Shao-Bo; Wei Zhi-Yi; Wu Hong-Ping; Pan Shi-Lie

    2016-01-01

    K 3 B 6 O 10 Cl (KBOC), a new nonlinear optical crystal, shows potential advantages for the generation of deep ultraviolet (UV) light compared with other borate crystals. In this paper we study for the first time the second harmonic generation (SHG) of a femtosecond Ti:sapphire amplifier with this crystal. Laser power is obtained to be as high as 220 mW at the central wavelength of 396 nm with a 1-mm-long crystal, and the maximum SHG conversion efficiency reaches 39.3%. The typical pulse duration is 83 fs. The results show that second harmonic (SH) conversion efficiency has the room to be further improved and that the new nonlinear crystal is very suited to generate the high efficiency deep ultraviolet laser radiation below 266 nm. (paper)

  13. crystal

    Science.gov (United States)

    Yu, Yi; Huang, Yisheng; Zhang, Lizhen; Lin, Zhoubin; Sun, Shijia; Wang, Guofu

    2014-07-01

    A Nd3+:Na2La4(WO4)7 crystal with dimensions of ϕ 17 × 30 mm3 was grown by the Czochralski method. The thermal expansion coefficients of Nd3+:Na2La4(WO4)7 crystal are 1.32 × 10-5 K-1 along c-axis and 1.23 × 10-5 K-1 along a-axis, respectively. The spectroscopic characteristics of Nd3+:Na2La4(WO4)7 crystal were investigated. The Judd-Ofelt theory was applied to calculate the spectral parameters. The absorption cross sections at 805 nm are 2.17 × 10-20 cm2 with a full width at half maximum (FWHM) of 15 nm for π-polarization, and 2.29 × 10-20 cm2 with a FWHM of 14 nm for σ-polarization. The emission cross sections are 3.19 × 10-20 cm2 for σ-polarization and 2.67 × 10-20 cm2 for π-polarization at 1,064 nm. The fluorescence quantum efficiency is 67 %. The quasi-cw laser of Nd3+:Na2La4(WO4)7 crystal was performed. The maximum output power is 80 mW. The slope efficiency is 7.12 %. The results suggest Nd3+:Na2La4(WO4)7 crystal as a promising laser crystal fit for laser diode pumping.

  14. Impact of Physical Abuse on Internalizing Behavior Across Generations.

    Science.gov (United States)

    Esteves, Kyle; Gray, Sarah A O; Theall, Katherine P; Drury, Stacy S

    2017-10-01

    This study investigated the multigenerational impact of mothers' own exposure to physical maltreatment on internalizing symptoms in her child after accounting for her parenting practices, depression, and the child's own exposure to stressful life events. Children ( n = 101, ages 5-16), predominantly African American, were recruited into this cross sectional study using ethnographic mapping and targeted sampling for high-risk neighborhoods. Mothers reported retrospectively on their own exposure to physical maltreatment in childhood, their parenting practices, as well as current depressive symptoms. Maternal report of her child's exposure to stressful life events and child behavior was also collected. Maternal childhood exposure to physical maltreatment was significantly associated with her child's internalizing symptoms ( p = .004); this effect remained after accounting for child sex, maternal depressive symptoms, harsh parenting practices, and the child's own exposure to stressful life events. Formal tests of mediation through these pathways were non-significant. Findings suggest mothers' experience of childhood maltreatment contributes uniquely to children's internalizing symptoms, potentially through previously uncharacterized pathways. Examination of additional behavioral, psychosocial and biological pathways may help better describe the multi-generational effects of child maltreatment.

  15. Genarris: Random generation of molecular crystal structures and fast screening with a Harris approximation

    Science.gov (United States)

    Li, Xiayue; Curtis, Farren S.; Rose, Timothy; Schober, Christoph; Vazquez-Mayagoitia, Alvaro; Reuter, Karsten; Oberhofer, Harald; Marom, Noa

    2018-06-01

    We present Genarris, a Python package that performs configuration space screening for molecular crystals of rigid molecules by random sampling with physical constraints. For fast energy evaluations, Genarris employs a Harris approximation, whereby the total density of a molecular crystal is constructed via superposition of single molecule densities. Dispersion-inclusive density functional theory is then used for the Harris density without performing a self-consistency cycle. Genarris uses machine learning for clustering, based on a relative coordinate descriptor developed specifically for molecular crystals, which is shown to be robust in identifying packing motif similarity. In addition to random structure generation, Genarris offers three workflows based on different sequences of successive clustering and selection steps: the "Rigorous" workflow is an exhaustive exploration of the potential energy landscape, the "Energy" workflow produces a set of low energy structures, and the "Diverse" workflow produces a maximally diverse set of structures. The latter is recommended for generating initial populations for genetic algorithms. Here, the implementation of Genarris is reported and its application is demonstrated for three test cases.

  16. 75 FR 11530 - Crystal Lake Wind III, LLC, et al.; Notice of Effectiveness of Exempt Wholesale Generator Status

    Science.gov (United States)

    2010-03-11

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Crystal Lake Wind III, LLC, et al.; Notice of Effectiveness of Exempt Wholesale Generator Status March 4, 2010. Docket Nos. Crystal Lake Wind III, LLC EG10-6-000 GardenGarden Wind, LLC EG10-7-000 Star Point Wind Project LLC EG10-8-000...

  17. Generation of symmetry coordinates for crystals using multiplier representations of the space groups

    DEFF Research Database (Denmark)

    Hansen, Flemming Yssing

    1978-01-01

    Symmetry coordinates play an important role in the normal-mode calculations of crystals. It is therefore of great importance to have a general method, which may be applied for any crystal at any wave vector, to generate these. The multiplier representations of the space groups as given by Kovalev...... and the projection-operator technique provide a basis for such a method. The method is illustrated for the nonsymmorphic D36 space group, and the theoretical background for the representations of space groups in general is reviewed and illustrated on the example above. It is desirable to perform the projection...... of symmetry coordinates in such a way that they may be used for as many wave vectors as possible. We discuss how to achieve this goal. The detailed illustrations should make it simple to apply the theory in any other case....

  18. Crystal Nucleation and Crystal Growth and Mass Transfer in Internally Mixed Sucrose/NaNO3 Particles.

    Science.gov (United States)

    Ji, Zhi-Ru; Zhang, Yun; Pang, Shu-Feng; Zhang, Yun-Hong

    2017-10-19

    Secondary organic aerosols (SOA) can exist in a glassy or semisolid state under low relative humidity (RH) conditions, in which the particles show nonequilibrium kinetic characteristics with changing ambient RH. Here, we selected internally mixed sucrose/NaNO 3 droplets with organic to inorganic molar ratios (OIRs) of 1:8, 1:4, 1:2, and 1:1 as a proxy for multicomponent ambient aerosols to study crystal nucleation and growth processes and water transport under a highly viscous state with the combination of an RH-controlling system and a vacuum Fourier transform infrared (FTIR) spectrometer. The initial efflorescence RH (ERH) of NaNO 3 decreased from ∼45% for pure NaNO 3 droplets to ∼38.6 and ∼37.9% for the 1:8 and 1:4 sucrose/NaNO 3 droplets, respectively, while no crystallization of NaNO 3 occurred for the 1:2 and 1:1 droplets in the whole RH range. Thus, the addition of sucrose delayed the ERH and even completely inhibited nucleation of NaNO 3 in the mixed droplets. In addition, the crystal growth of NaNO 3 was suppressed in the 1:4 and 1:8 droplets most likely due to the slow diffusion of Na + and NO 3 - ions at low RH. Water uptake/release of sucrose/NaNO 3 particles quickly arrived at equilibrium at high RH, while the hygroscopic process was kinetically controlled under low RH. The half-time ratio between the liquid water content and the RH was used to describe the mass transfer behavior. For the 1:1 droplets, no mass limitation was observed with the ratio approaching to 1 when the RH was higher than 53%. The ratio increased 1 order of magnitude under an ultraviscous state with RH ranging from 53 to 15% and increased a further 1 order of magnitude at RH < 15% under a glassy state.

  19. Integrating Renewable Generation into Grid Operations: Four International Experiences

    Energy Technology Data Exchange (ETDEWEB)

    Weimar, Mark R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mylrea, Michael E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Levin, Todd [Argonne National Lab. (ANL), Argonne, IL (United States); Botterud, Audun [Argonne National Lab. (ANL), Argonne, IL (United States); O' Shaughnessy, Eric [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bird, Lori [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-04-22

    International experiences with power sector restructuring and the resultant impacts on bulk power grid operations and planning may provide insight into policy questions for the evolving United States power grid as resource mixes are changing in response to fuel prices, an aging generation fleet and to meet climate goals. Australia, Germany, Japan and the UK were selected to represent a range in the level and attributes of electricity industry liberalization in order to draw comparisons across a variety of regions in the United States such as California, ERCOT, the Southwest Power Pool and the Southeast Reliability Region. The study draws conclusions through a literature review of the four case study countries with regards to the changing resource mix and the electricity industry sector structure and their impact on grid operations and planning. This paper derives lessons learned and synthesizes implications for the United States based on answers to the above questions and the challenges faced by the four selected countries. Each country was examined to determine the challenges to their bulk power sector based on their changing resource mix, market structure, policies driving the changing resource mix, and policies driving restructuring. Each countries’ approach to solving those changes was examined, as well as how each country’s market structure either exacerbated or mitigated the approaches to solving the challenges to their bulk power grid operations and planning. All countries’ policies encourage renewable energy generation. One significant finding included the low- to zero-marginal cost of intermittent renewables and its potential negative impact on long-term resource adequacy. No dominant solution has emerged although a capacity market was introduced in the UK and is being contemplated in Japan. Germany has proposed the Energy Market 2.0 to encourage flexible generation investment. The grid operator in Australia proposed several approaches to maintaining

  20. Dynamics of Dispersive Wave Generation in Gas-Filled Photonic Crystal Fiber with the Normal Dispersion

    Directory of Open Access Journals (Sweden)

    Zhixiang Deng

    2017-01-01

    Full Text Available The absence of Raman and unique pressure-tunable dispersion is the characteristic feature of gas-filled photonic crystal fiber (PCF, and its zero dispersion points can be extended to the near-infrared by increasing gas pressure. The generation of dispersive wave (DW in the normal group velocity dispersion (GVD region of PCF is investigated. It is demonstrated that considering the self-steepening (SS and introducing the chirp of the initial input pulse are two suitable means to control the DW generation. The SS enhances the relative average intensity of blue-shift DW while weakening that of red-shift DW. The required propagation distance of DW emission is markedly varied by introducing the frequency chirp. Manipulating DW generation in gas-filled PCF by the combined effects of either SS or chirp and three-order dispersion (TOD provides a method for a concentrated transfer of energy into the targeted wavelengths.

  1. Spectral distribution of the efficiency of terahertz difference frequency generation upon collinear propagation of interacting waves in semiconductor crystals

    International Nuclear Information System (INIS)

    Orlov, Sergei N; Polivanov, Yurii N

    2007-01-01

    Dispersion phase matching curves and spectral distributions of the efficiency of difference frequency generation in the terahertz range are calculated for collinear propagation of interacting waves in zinc blende semiconductor crystals (ZnTe, CdTe, GaP, GaAs). The effect of the pump wavelength, the nonlinear crystal length and absorption in the terahertz range on the spectral distribution of the efficiency of difference frequency generation is analysed. (nonlinear optical phenomena)

  2. Ice crystallization in ultrafine water-salt aerosols: nucleation, ice-solution equilibrium, and internal structure.

    Science.gov (United States)

    Hudait, Arpa; Molinero, Valeria

    2014-06-04

    Atmospheric aerosols have a strong influence on Earth's climate. Elucidating the physical state and internal structure of atmospheric aqueous aerosols is essential to predict their gas and water uptake, and the locus and rate of atmospherically important heterogeneous reactions. Ultrafine aerosols with sizes between 3 and 15 nm have been detected in large numbers in the troposphere and tropopause. Nanoscopic aerosols arising from bubble bursting of natural and artificial seawater have been identified in laboratory and field experiments. The internal structure and phase state of these aerosols, however, cannot yet be determined in experiments. Here we use molecular simulations to investigate the phase behavior and internal structure of liquid, vitrified, and crystallized water-salt ultrafine aerosols with radii from 2.5 to 9.5 nm and with up to 10% moles of ions. We find that both ice crystallization and vitrification of the nanodroplets lead to demixing of pure water from the solutions. Vitrification of aqueous nanodroplets yields nanodomains of pure low-density amorphous ice in coexistence with vitrified solute rich aqueous glass. The melting temperature of ice in the aerosols decreases monotonically with an increase of solute fraction and decrease of radius. The simulations reveal that nucleation of ice occurs homogeneously at the subsurface of the water-salt nanoparticles. Subsequent ice growth yields phase-segregated, internally mixed, aerosols with two phases in equilibrium: a concentrated water-salt amorphous mixture and a spherical cap-like ice nanophase. The surface of the crystallized aerosols is heterogeneous, with ice and solution exposed to the vapor. Free energy calculations indicate that as the concentration of salt in the particles, the advance of the crystallization, or the size of the particles increase, the stability of the spherical cap structure increases with respect to the alternative structure in which a core of ice is fully surrounded by

  3. Solvent Vapor Annealing-Mediated Crystallization Directs Charge Generation, Recombination and Extraction in BHJ Solar Cells

    KAUST Repository

    Babics, Maxime; Liang, Ru-Ze; Wang, Kai; Cruciani, Federico; Kan, Zhipeng; Wohlfahrt, Markus; Tang, Ming-Chun; Laquai, Fré dé ric; Beaujuge, Pierre

    2017-01-01

    Small-molecule (SM) donors that can be solution-processed with fullerene acceptors (e.g., PC61/71BM), or their “nonfullerene” counterparts, are proving particularly promising for the realization of high-efficiency bulk-heterojunction (BHJ) solar cells. In several recent studies, solvent vapor annealing (SVA) protocols have been found to yield significant BHJ device efficiency improvements via structural changes in the active layer morphologies. However, the mechanisms by which active layer morphologies evolve when subjected to SVA treatments, and the structural factors impacting charge generation, carrier transport, recombination and extraction in BHJ solar cells with SM donors and fullerene acceptors, remain important aspects to be elucidated. In this report, we show that – in BHJ solar cells with SM donors and fullerene acceptors – selective crystallization promoted by SVA mediates the development of optimized morphologies across the active layers, setting domain sizes and boundaries. Examining BHJ solar cells subjected to various SVA exposure times, with BDT[2F]QdC as the SM donor and PC71BM as the acceptor, we connect those morphological changes to specific carrier effects, showing that crystal growth effectively directs charge generation and recombination. We find that the SM donor-pure domains growing at the expense of a mixed donor-acceptor phase play a determining role, establishing optimum networks with 10-20nm-sized domains during the SVA treatment. Longer SVA times result in highly textured active layers with crystalline domains that can exceed the lengthscale of exciton diffusion, while inducing detrimental vertical morphologies and deep carrier traps. Last, we emphasize the field-dependence charge generation occurring upon SVA-mediated crystallization and link this carrier effect to the mixed phase depletion across the BHJ active layer.

  4. Solvent Vapor Annealing-Mediated Crystallization Directs Charge Generation, Recombination and Extraction in BHJ Solar Cells

    KAUST Repository

    Babics, Maxime

    2017-12-19

    Small-molecule (SM) donors that can be solution-processed with fullerene acceptors (e.g., PC61/71BM), or their “nonfullerene” counterparts, are proving particularly promising for the realization of high-efficiency bulk-heterojunction (BHJ) solar cells. In several recent studies, solvent vapor annealing (SVA) protocols have been found to yield significant BHJ device efficiency improvements via structural changes in the active layer morphologies. However, the mechanisms by which active layer morphologies evolve when subjected to SVA treatments, and the structural factors impacting charge generation, carrier transport, recombination and extraction in BHJ solar cells with SM donors and fullerene acceptors, remain important aspects to be elucidated. In this report, we show that – in BHJ solar cells with SM donors and fullerene acceptors – selective crystallization promoted by SVA mediates the development of optimized morphologies across the active layers, setting domain sizes and boundaries. Examining BHJ solar cells subjected to various SVA exposure times, with BDT[2F]QdC as the SM donor and PC71BM as the acceptor, we connect those morphological changes to specific carrier effects, showing that crystal growth effectively directs charge generation and recombination. We find that the SM donor-pure domains growing at the expense of a mixed donor-acceptor phase play a determining role, establishing optimum networks with 10-20nm-sized domains during the SVA treatment. Longer SVA times result in highly textured active layers with crystalline domains that can exceed the lengthscale of exciton diffusion, while inducing detrimental vertical morphologies and deep carrier traps. Last, we emphasize the field-dependence charge generation occurring upon SVA-mediated crystallization and link this carrier effect to the mixed phase depletion across the BHJ active layer.

  5. Ultrashort pulse chirp measurement via transverse second-harmonic generation in strontium barium niobate crystal

    Energy Technology Data Exchange (ETDEWEB)

    Trull, J.; Wang, B.; Parra, A.; Vilaseca, R.; Cojocaru, C. [Departament de Física i Enginyeria Nuclear, Universitat Politècnica Catalunya, Terrassa 08222 (Spain); Sola, I. [Grupo de Investigación en Óptica Extrema (GIOE), Departamento de Física Aplicada, Universidad de Salamanca, Plaza de la Merced s/n, 37008 Salamanca (Spain); Krolikowski, W. [Laser Physics Centre, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia); Science Program, Texas A and M University at Qatar, Doha (Qatar); Sheng, Y. [Laser Physics Centre, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia)

    2015-06-01

    Pulse compression in dispersive strontium barium niobate crystal with a random size and distribution of the anti-parallel orientated nonlinear domains is observed via transverse second harmonic generation. The dependence of the transverse width of the second harmonic trace along the propagation direction allows for the determination of the initial chirp and duration of pulses in the femtosecond regime. This technique permits a real-time analysis of the pulse evolution and facilitates fast in-situ correction of pulse chirp acquired in the propagation through an optical system.

  6. Ultrashort pulse chirp measurement via transverse second-harmonic generation in strontium barium niobate crystal

    International Nuclear Information System (INIS)

    Trull, J.; Wang, B.; Parra, A.; Vilaseca, R.; Cojocaru, C.; Sola, I.; Krolikowski, W.; Sheng, Y.

    2015-01-01

    Pulse compression in dispersive strontium barium niobate crystal with a random size and distribution of the anti-parallel orientated nonlinear domains is observed via transverse second harmonic generation. The dependence of the transverse width of the second harmonic trace along the propagation direction allows for the determination of the initial chirp and duration of pulses in the femtosecond regime. This technique permits a real-time analysis of the pulse evolution and facilitates fast in-situ correction of pulse chirp acquired in the propagation through an optical system

  7. Domain-Reversed Lithium Niobate Single-Crystal Fibers are Potentially for Efficient Terahertz Wave Generation

    Directory of Open Access Journals (Sweden)

    Yalin Lu

    2008-01-01

    Full Text Available Nonlinear frequency conversion remains one of the dominant approaches to efficiently generate THz waves. Significant material absorption in the THz range is the main factor impeding the progress towards this direction. In this research, a new multicladding nonlinear fiber design was proposed to solve this problem, and as the major experimental effort, periodic domain structure was introduced into lithium niobate single-crystal fibers by electrical poling. The introduced periodic domain structures were nondestructively revealed using a crossly polarized optical microscope and a confocal scanning optical microscope for quality assurance.

  8. Generation, detection and spectroscopic studies of high-frequency nonequilibrium phonons in crystals

    International Nuclear Information System (INIS)

    Dennis, W.M.; Yen, W.M.

    2007-01-01

    In this article we will review studies conducted in the past two decades on the dynamic properties of high-frequency (THz) phonons generated monochromatically with high power far infrared (FIR) laser pulses using defect-induced phonon absorption and detected using a vibronic sideband spectrometer fashioned after that devised by Kaplyanskii, the honoree of this special issue. The temporal and spectral evolution of the phonon signature provides information on the mechanisms that dominate the relaxation of high-frequency phonons in real crystals

  9. Simulation of light generation in cholesteric liquid crystals using kinetic equations: Time-independent solution

    Energy Technology Data Exchange (ETDEWEB)

    Shtykov, N. M., E-mail: nshtykov@mail.ru; Palto, S. P.; Umanskii, B. A. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2013-08-15

    We report on the results of calculating the conditions for light generation in cholesteric liquid crystals doped with fluorescent dyes using kinetic equations. Specific features of spectral properties of the chiral cholesteric medium as a photonic structure and spatially distributed type of the feedback in the active medium are taken into account. The expression is derived for the threshold pump radiation intensity as a function of the dye concentration and sample thickness. The importance of taking into account the distributed loss level in the active medium for calculating the optimal parameters of the medium and for matching the calculated values with the results of experiments is demonstrated.

  10. Atomically Phase-Matched Second-Harmonic Generation in a 2D Crystal

    Science.gov (United States)

    2016-08-26

    OPEN ORIGINAL ARTICLE Atomically phase-matched second-harmonic generation in a 2D crystal Mervin Zhao1,2,*, Ziliang Ye1,2,*, Ryuji Suzuki3,4,*, Yu...photoluminescence mapping, Raman spectroscopy and atomic -force microscopy. (b) Image produced via scanning and gathering the SH light produced by the 3R-MoS2...arising from a single atomic layer, where the SH light elucidated important information such as the grain boundaries and electronic structure in these ultra

  11. Role of internal demagnetizing field for the dynamics of a surface-modulated magnonic crystal

    Science.gov (United States)

    Langer, M.; Röder, F.; Gallardo, R. A.; Schneider, T.; Stienen, S.; Gatel, C.; Hübner, R.; Bischoff, L.; Lenz, K.; Lindner, J.; Landeros, P.; Fassbender, J.

    2017-05-01

    This work aims to demonstrate and understand the key role of local demagnetizing fields in hybrid structures consisting of a continuous thin film with a stripe modulation on top. To understand the complex spin dynamics of these structures, the magnonic crystal was reconstructed in two different ways—performing micromagnetic simulations based on the structural shape as well as based on the internal demagnetizing field, which both are mapped on the nanoscale using electron holography. The simulations yield the frequency-field dependence as well as the angular dependence revealing the governing role of the internal field landscape around the backward-volume geometry. Simple rules for the propagation vector and the mode localization are formulated in order to explain the calculated mode profiles. Treating internal demagnetizing fields equivalent to anisotropies, the complex angle-dependent spin-wave behavior is described for an in-plane rotation of the external field.

  12. Controlled parallel crystallization of lithium disilicate and diopside using a combination of internal and surface nucleation

    Directory of Open Access Journals (Sweden)

    Markus Rampf

    2016-10-01

    Full Text Available In the mid-19th century, Dr. Donald Stookey identified the importance and usability of nucleating agents and mechanisms for the development of glass-ceramic materials. Today, a number of various internal and surface mechanisms as well as combinations thereof have been established in the production of glass-ceramic materials. In order to create new innovative material properties the present study focuses on the precipitation of CaMgSiO6 as a minor phase in Li2Si2O5 based glass-ceramics. In the base glass of the SiO2-Li2O-P2O5-Al2O3-K2O-MgO-CaO system P2O5 serves as nucleating agent for the internal precipitation of Li2Si2O5 crystals while a mechanical activation of the glass surface by means of ball milling is necessary to nucleate the minor CaMgSi2O6 crystal phase. For a successful precipitation of CaMgSi2O6 a minimum ratio of MgO and CaO in the range between 1.4 mol% and 2.9 mol% in the base glasses was determined. The nucleation and crystallization of both crystal phases takes place during sintering a powder compact. Dependent on the quality of the sintering process the dense Li2Si2O5-CaMgSi2O6 glass-ceramics show a mean biaxial strength of up to 392 ± 98 MPa. The microstructure of the glass-ceramics is formed by large (5-10 µm bar like CaMgSi2O6 crystals randomly embedded in a matrix of small (≤ 0.5 µm plate like Li2Si2O5 crystals arranged in an interlocking manner. While there is no significant influence of the minor CaMgSi2O6 phase on the strength of the material, the translucency of the material decreases upon precipitation of the minor phase.

  13. Effects of the rate of supersaturation generation on polymorphic crystallization of m-hydroxybenzoic acid and o-aminobenzoic acid

    Science.gov (United States)

    He, Guangwen; Wong, Annie B. H.; Chow, Pui Shan; Tan, Reginald B. H.

    2011-01-01

    Effects of the rate of supersaturation generation on polymorphic crystallization have been investigated through evaporation and cooling crystallization experiments of m-hydroxybenzoic acid (m-HBA) in methanol, acetone and ethyl acetate, and o-aminobenzoic acid (o-ABA) in ethanol. The rate of supersaturation generation has been altered by systematically changing either the cooling rate or the evaporation rate of solvent using a jacketed crystallizer and a microfluidic evaporation device, respectively. The results have revealed that the rate of supersaturation generation and the tendency of the formation of the less stable polymorph are positively correlated. Kinetic effects are dominant when the rate of supersaturation generation is high, thereby producing the metastable polymorphs (orthorhombic m-HBA; Form II of o-ABA); on the contrary, more stable polymorphs (monoclinic m-HBA; Forms III and I of o-ABA) are formed when the rate of supersaturation generation is low and the thermodynamic effects are prevailing.

  14. Extension of supercontinuum spectrum, generated in polarization-maintaining photonic crystal fiber, using chirped femtosecond pulses

    Science.gov (United States)

    Vengelis, Julius; Jarutis, Vygandas; Sirutkaitis, Valdas

    2018-01-01

    We present results of experimental and numerical investigation of supercontinuum (SC) generation in polarization-maintaining photonic crystal fiber (PCF) using chirped femtosecond pulses. The initial unchirped pump pulse source was a mode-locked Yb:KGW laser generating 52-nJ energy, 110-fs duration pulses at 1030 nm with a 76-MHz repetition rate. The nonlinear medium was a 32-cm-long polarization-maintaining PCF manufactured by NKT Photonics A/S. We demonstrated the influence of pump pulse chirp on spectral characteristics of a SC. We showed that by chirping pump pulses positively or negatively one can obtain a broader SC spectrum than in the case of unchirped pump pulses at the same peak power. Moreover, the extension can be controlled by changing the amount of pump pulse chirp. Numerical simulation results also indicated that pump pulse chirp yields an extension of SC spectrum.

  15. Development of the RTP crystal applications for Q-switching operation and second harmonics generation

    International Nuclear Information System (INIS)

    Alnayli, R.Sh.

    2010-01-01

    Complete text of publication follows. A dialed theoretical studies on performances of the ideal RTP crystal for the electro optical applications as Q-switching laser operation and for nonlinear optics application as second harmonics generation are accomplished in this paper. Single or pair RTP crystal of excellent quality with dimensions 5 x 5 x 7.5 mm 3 have proposed as element model to combined Q-switching operation and frequency doublers for 1.06 μm wave length laser. In order to get and interpolate the optimum conditions to combined both of these operations by application this RTP model. The main am of this work was investigated the most influent parameters on the performance of the electro optical Q-switching laser operation such as, the voltage requirement, contrast and extinction ratios, the birefringence effective and withstand threshold on the other hand the influences of the ray walk off, thermal effective on the efficiency of the second harmonics generation as well are investigated. The results were satisfied for the goals of this paper.

  16. The charm of protein crystals--Structural biology at a glance in the International Year of Crystallography

    International Nuclear Information System (INIS)

    Su Xiaodong; Cao Qin

    2014-01-01

    Crystallography is a typical intellectual endeavor that has spanned human history for centuries. Through the persistent efforts of generations of scientists, crystallography has been transformed from a mathematical hypothesis to actual physical reality, mainly thanks to X-ray diffraction technology. 2014 is celebrated as the International Year of Crystallography (IYCr-2014), to commemorate that about 100 years ago, when Max von Laue in Germany and the father-and-son Braggs (William Henry Bragg and William Lawrence Bragg) in England pioneered the use of X-rays to determine the atomic structure of crystals; for this pioneering work they were awarded Nobel prizes for physics in the years of 1914 and 1915. This article is dedicated to the IYCr to describe the use of protein crystals, an application that has developed into protein crystallography and subsequently structural biology. In our overview of the history and future prospects of this field, we discuss in detail one example of caspase-6, to demonstrate how protein crystallography can help us understand the structure-function relationship of important proteins. (authors)

  17. Experimental study of internal conical refraction in a biaxial crystal with Laguerre–Gauss light beams

    International Nuclear Information System (INIS)

    Peet, V

    2014-01-01

    The effect of internal conical refraction (CR) in a biaxial crystal was studied using Laguerre–Gauss light beams LG 0 ℓ with ℓ=1 and 2, while the lowest-order LG 0 0 beam was used as a reference. The transition from ordinary double refraction to CR was examined. It has been shown that double refraction of an LG 0 ℓ beam forms two focal spots containing ℓ dark stripes. These stripes evolve into ℓ+1 dark rings over an annular focal image when CR is established, and it results in a fine-structure of ℓ+2 bright focal rings with different intensities. In a sharp contrast to the lowest-order reference, the multiring focal structure has a distinct asymmetry with respect to the focal image plane. It has been shown that bright off-axis ‘hot spot’ can be formed on the far-field profiles of outgoing light beams when the biaxial crystal is slightly tilted, and a small angle between the propagation axis of the beam and the optic axis of the crystal arises. These off-axis light structures emerge as either a charge-one optical vortex or a zero-charge spot with annihilated vorticity. Polarization selection reveals J 1 or J 0 Bessel-like profiles of the corresponding ‘hot spots’, and a complex pattern of forked fringes in the dark region near the beam core. (paper)

  18. Internal and ancestral controls of cell-generation times

    Science.gov (United States)

    Kubitschek, H. E.

    1969-01-01

    Lateral and longitudinal correlations between related cells reveal associations between the generation times of cells for an intermediate period /three generations in bacteral cultures/. Generation times of progeny are influenced by nongenetic factors transmitted from their ancestors.

  19. Modeling internal wave generation by seamounts in oceans

    Science.gov (United States)

    Zhang, L.; Buijsman, M. C.; Comino, E. L.; Swinney, H.

    2017-12-01

    Recent global bathymetric data at 30 arc-sec resolution has revealed that there are 33,452 seamounts and 138,412 knolls in the oceans. To develop an estimate for the energy converted from tidal flow to internal gravity waves, we have conducted numerical simulations using the Massachusetts Institute of Technology circulation model (MITgcm) to compute the energy conversion by randomly distributed Gaussian-shaped seamounts. We find that for an isolated axisymmetric seamount of height 1100 m and radius 1600 m, which corresponds to the Wessel height-to-radius ratio 0.69, the conversion rate is 100 kW, assuming a tidal speed amplitude 1 cm/s, buoyancy frequency 1e-3 rad/s, and circularly polarized tidal motion, and taking into account the earth's rotation. The 100 kW estimate is about 60% less than the 3-D linear theory prediction because fluid goes around a seamount instead of over it. Our estimate accounts the suppression of energy conversion due to wave interference at the generation site of closely spaced seamounts. We conclude that for randomly distributed Gaussian seamounts of varying widths and separations, separated on average by 18 km as in the oceans, wave interference reduces the energy conversion by seamounts by only about 16%. This result complements previous studies of wave interference for 2-D ridges.

  20. Thermal mechanical analysis of applications with internal heat generation

    Science.gov (United States)

    Govindarajan, Srisharan Garg

    The radioactive tracer Technetium-99m is widely used in medical imaging and is derived from its parent isotope Molybedenum-99 (Mo-99) by radioactive decay. The majority of Molybdenum-99 (Mo-99) produced internationally is extracted from high enriched uranium (HEU) dispersion targets that have been irradiated. To alleviate proliferation risks associated with HEU-based targets, the use of non-HEU sources is being mandated. However, the conversion of HEU to LEU based dispersion targets affects the Mo-99 available for chemical extraction. A possible approach to increase the uranium density, to recover the loss in Mo-99 production-per-target, is to use an LEU metal foil placed within an aluminum cladding to form a composite structure. The target is expected to contain the fission products and to dissipate the generated heat to the reactor coolant. In the event of interfacial separation, an increase in the thermal resistance could lead to an unacceptable rise in the LEU temperature and stresses in the target. The target can be deemed structurally safe as long as the thermally induced stresses are within the yield strength of the cladding and welds. As with the thermal and structural safety of the annular target, the thermally induced deflection of the BORALRTM-based control blades, used by the University of Missouri Research Reactor (MURRRTM ), during reactor operation has been analyzed. The boron, which is the neutron absorber in BORAL, and aluminum mixture (BORAL meat) and the aluminum cladding are bonded together through powder metallurgy to establish an adherent bonded plate. As the BORAL absorbs both neutron particles and gamma rays, there is volumetric heat generation and a corresponding rise in temperature. Since the BORAL meat and aluminum cladding materials have different thermal expansion coefficients, the blade may have a tendency to deform as the blade temperature changes and the materials expand at different rates. In addition to the composite nature of the

  1. Filament-induced luminescence and supercontinuum generation in undoped, Yb-doped, and Nd-doped YAG crystals

    Science.gov (United States)

    Kudarauskas, D.; Tamošauskas, G.; Vengris, M.; Dubietis, A.

    2018-01-01

    We present a comparative spectral study of filament-induced luminescence and supercontinuum generation in undoped, Yb-doped, and Nd-doped YAG crystals. We show that supercontinuum spectra generated by femtosecond filamentation in undoped and doped YAG crystals are essentially identical in terms of spectral extent. On the other hand, undoped and doped YAG crystals exhibit remarkably different filament-induced luminescence spectra whose qualitative features are independent of the excitation wavelength and provide information on the energy deposition to embedded dopants, impurities, and the crystal lattice itself. Our findings suggest that filament-induced luminescence may serve as a simple and non-destructive tool for spectroscopic studies in various transparent dielectric media.

  2. Crystallization of aqueous ammonium sulfate particles internally mixed with soot and kaolinite: crystallization relative humidities and nucleation rates.

    Science.gov (United States)

    Pant, Atul; Parsons, Matthew T; Bertram, Allan K

    2006-07-20

    Using optical microscopy, we investigated the crystallization of aqueous ammonium sulfate droplets containing soot and kaolinite, as well as the crystallization of aqueous ammonium sulfate droplets free of solid material. Our results show that soot did not influence the crystallization RH of aqueous ammonium sulfate particles under our experimental conditions. In contrast, kaolinite increased the crystallization RH of the aqueous ammonium sulfate droplets by approximately 10%. In addition, our results show that the crystallization RH of aqueous ammonium sulfate droplets free of solid material does not depend strongly on particle size. This is consistent with conclusions made previously in the literature, based on comparisons of results from different laboratories. From the crystallization results we determined the homogeneous nucleation rates of crystalline ammonium sulfate in aqueous ammonium sulfate droplets and the heterogeneous nucleation rates of crystalline ammonium sulfate in aqueous ammonium sulfate particles containing kaolinite. Using classical nucleation theory and our experimental data, we determined that the interfacial tension between an ammonium sulfate critical nucleus and an aqueous ammonium sulfate solution is 0.064 +/- 0.003 J m(-2) (in agreement with our previous measurements), and the contact angle between an ammonium sulfate critical nucleus and a kaolinite surface is 59 +/- 2 degrees. On the basis of our results, we argue that soot will not influence the crystallization RH of aqueous ammonium sulfate droplets in the atmosphere, but kaolinite can significantly modify the crystallization RH of atmospheric ammonium sulfate droplets. As an example, the CRH50 (the relative humidity at which 50% of the droplets crystallize) ranges from about 41 to 51% RH when the diameter of the kaolinite inclusion ranges from 0.1 to 5 microm. For comparison, the CRH50 of aqueous ammonium sulfate droplets (0.5 microm diameter) free of solid material is

  3. Generation 4 International Forum. 2009 GIF R and D outlook for generation 4 nuclear energy systems

    International Nuclear Information System (INIS)

    2009-01-01

    This document presents the state, at mid 2009, of research and development of the 6 reactor types that were selected in the framework of the GIF (Generation 4 International Forum): VHTR (Very High Temperature Reactor), SFR (Sodium-cooled Fast Reactor), SCWR (Super-Critical Water Reactor), GFR (Gas-cooled Fast Reactor), LFR (Lead-cooled reactor), and MSR (Molten Salt Reactor). Regarding each type of reactors, the state of advancement is reported for the reactor itself, its specific components and materials, its nuclear fuel, and its fuel cycle. The outlook of development and research work is also given for the next 5 years for the 6 types of reactors. (A.C.)

  4. Ion Transport and Precipitation Kinetics as Key Aspects of Stress Generation on Pore Walls Induced by Salt Crystallization

    Science.gov (United States)

    Naillon, A.; Joseph, P.; Prat, M.

    2018-01-01

    The stress generation on pore walls due to the growth of a sodium chloride crystal in a confined aqueous solution is studied from evaporation experiments in microfluidic channels in conjunction with numerical computations of crystal growth. The study indicates that the stress buildup on the pore walls is a highly transient process taking place over a very short period of time (in less than 1 s in our experiments). The analysis makes clear that what matters for the stress generation is not the maximum supersaturation at the onset of the crystal growth but the supersaturation at the interface between the solution and the crystal when the latter is about to be confined between the pore walls. The stress generation is summarized in a simple stress diagram involving the pore aspect ratio and the Damkhöler number characterizing the competition between the precipitation reaction kinetics and the ion transport towards the growing crystal. This opens up the route for a better understanding of the damage of porous materials induced by salt crystallization, an important issue in Earth sciences, reservoir engineering, and civil engineering.

  5. Generating Bona Fide Mammalian Prions with Internal Deletions.

    Science.gov (United States)

    Munoz-Montesino, Carola; Sizun, Christina; Moudjou, Mohammed; Herzog, Laetitia; Reine, Fabienne; Chapuis, Jérôme; Ciric, Danica; Igel-Egalon, Angelique; Laude, Hubert; Béringue, Vincent; Rezaei, Human; Dron, Michel

    2016-08-01

    disorders. Other aggregation-prone proteins appear to have a prion-like mode of expansion in brains, such as in Alzheimer's or Parkinson's diseases. To date, the resolution of prion structure remains elusive. Thus, to genetically define the landscape of regions critical for prion conversion, we tested the effect of short deletions. We found that, surprisingly, removal of a portion of PrP, the C terminus of alpha-helix H2, did not hamper prion formation but generated infectious agents with an internal deletion that showed characteristics essentially similar to those of original infecting strains. Thus, we demonstrate that completeness of the residues inside prions is not necessary for maintaining infectivity and the main strain-specific information, while reporting one of the few if not the only bona fide prions with an internal deletion. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  6. Ultrabroadband, Midinfrared Supercontinuum Generation in Dispersion Engineered As2Se3-Based Chalcogenide Photonic Crystal Fibers

    Directory of Open Access Journals (Sweden)

    Rim Cherif

    2013-01-01

    Full Text Available Small core As2Se3-based photonic crystal fibers (PCFs are accurately characterized for compact, high power, ultrabroadband, and coherent supercontinuum generation within few millimeters fiber length. Bandwidths of ~5.3 μm, 5 μm, and 3.2 μm were calculated for hole-to-hole spacings Λ= 3.5 μm, 4.5 μm, and 5.5 μm, respectively. The spectral broadening in the chalcogenide PCF is mainly caused by self-phase modulation and Raman-induced soliton self-frequency shift. The results show that small core As2Se3 PCFs are a promising candidate for mid-IR SCG up to ~8 μm.

  7. Analysis of laser-generated plasma ionizing radiation by synthetic single crystal diamond detectors

    Czech Academy of Sciences Publication Activity Database

    Marinelli, M.; Milani, E.; Prestopino, G.; Verona, C.; Verona-Rinati, G.; Cutroneo, M.; Torrisi, L.; Margarone, Daniele; Velyhan, Andriy; Krása, Josef; Krouský, Eduard

    2013-01-01

    Roč. 272, May (2013), s. 104-108 ISSN 0169-4332 R&D Projects: GA MŠk ED1.1.00/02.0061; GA MŠk EE2.3.20.0279; GA MŠk EE.2.3.20.0087; GA MŠk(CZ) 7E09092; GA MŠk(CZ) LC528 Grant - others:ELI Beamlines(XE) CZ.1.05/1.1.00/02.0061; OPVK 3 Laser Zdroj(XE) CZ.1.07/2.3.00/20.0279; OP VK 2 LaserGen(XE) CZ.1.07/2.3.00/20.0087; 7FP LASERLAB-EUROPE(XE) 228334 Program:EE; FP7 Institutional support: RVO:68378271 Keywords : single crystal diamond * diamond detector * laser-generated plasma * ionizing radiation * time-of-fight spectrometer Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.538, year: 2013

  8. Alternative generation of well-aligned uniform lying helix texture in a cholesteric liquid crystal cell

    Directory of Open Access Journals (Sweden)

    Chia-Hua Yu

    2017-10-01

    Full Text Available This work demonstrates a simple approach for obtaining a well-aligned uniform lying helix (ULH texture and a tri-bistable feature at ambient temperature in a typical 90°-twisted cell filled with a short-pitch cholesteric liquid crystal. This ULH texture is obtained at room temperature from initially field-induced helix-free homeotropic state by gradually decreasing the applied voltage. Depending on the way and rate of reducing the voltage, three stable states (i.e., Grandjean planar, focal conic, and ULH are generated and switching between any two of them is realized. Moreover, the electrical operation of the cell in the ULH state enables the tunability in phase retardation via the deformation of the ULH. The observations made in this work may be useful for applications such as tunable phase modulators and energy-efficient photonic devices.

  9. Generation of crystal-structure transverse patterns via a self-frequency-doubling laser.

    Science.gov (United States)

    Yu, Haohai; Zhang, Huaijin; Wang, Yicheng; Wang, Zhengping; Wang, Jiyang; Petrov, V

    2013-01-01

    Two-dimensional (2D) visible crystal-structure patterns analogous to the quantum harmonic oscillator (QHO) have been experimentally observed in the near- and far-fields of a self-frequency-doubling (SFD) microchip laser. Different with the fundamental modes, the localization of the SFD light is changed with the propagation. Calculation based on Hermite-Gaussian (HG) functions and second harmonic generation theory reproduces well the patterns both in the near- and far-field which correspond to the intensity distribution in coordinate and momentum spaces, respectively. Considering the analogy of wave functions of the transverse HG mode and 2D harmonic oscillator, we propose that the simple monolithic SFD lasers can be used for developing of new materials and devices and testing 2D quantum mechanical theories.

  10. Tunable microwave signal generation based on an Opto-DMD processor and a photonic crystal fiber

    International Nuclear Information System (INIS)

    Wang Tao; Sang Xin-Zhu; Yan Bin-Bin; Li Yan; Song Fei-Jun; Zhang Xia; Wang Kui-Ru; Yuan Jin-Hui; Yu Chong-Xiu; Ai Qi; Chen Xiao; Zhang Ying; Chen Gen-Xiang; Xiao Feng; Kamal Alameh

    2014-01-01

    Frequency-tunable microwave signal generation is proposed and experimentally demonstrated with a dual-wavelength single-longitudinal-mode (SLM) erbium-doped fiber ring laser based on a digital Opto-DMD processor and four-wave mixing (FWM) in a high-nonlinear photonic crystal fiber (PCF). The high-nonlinear PCF is employed for the generation of the FWM to obtain stable and uniform dual-wavelength oscillation. Two different short passive sub-ring cavities in the main ring cavity serve as mode filters to make SLM lasing. The two lasing wavelengths are electronically selected by loading different gratings on the Opto-DMD processor controlled with a computer. The wavelength spacing can be smartly adjusted from 0.165 nm to 1.08 nm within a tuning accuracy of 0.055 nm. Two microwave signals at 17.23 GHz and 27.47 GHz are achieved. The stability of the microwave signal is discussed. The system has the ability to generate a 137.36-GHz photonic millimeter signal at room temperature

  11. Status Report and Research Plan for Cables Harvested from Crystal River Unit 3 Nuclear Generating Plant

    Energy Technology Data Exchange (ETDEWEB)

    Fifield, Leonard S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-09-20

    Harvested cables from operating or decommissioned nuclear power plants present an important opportunity to validate models, understanding material aging behavior, and validate characterization techniques. Crystal River Unit 3 Nuclear Generating Plant is a pressurized water reactor that was licensed to operate from 1976 to 2013. Cable segments were harvested and made available to the Light Water Reactor Sustainability research program through the Electric Power Research Institute. Information on the locations and circuits within the reactor from whence the cable segments came, cable construction, sourcing and installation information, and photographs of the cable locations prior to harvesting were provided. The cable variations provided represent six of the ten most common cable insulations in the nuclear industry and experienced service usage for periods from 15 to 42 years. Subsequently, these cables constitute a valuable asset for research to understand aging behavior and measurement of nuclear cables. Received cables harvested from Crystal River Unit 3 Nuclear Generating Plant consist of low voltage, insulated conductor surrounded by jackets in lengths from 24 to 100 feet each. Cable materials will primarily be used to investigate aging under simultaneous thermal and gamma radiation exposure. Each cable insulation and jacket material will be characterized in its as-received condition, including determination of the temperatures associated with endothermic transitions in the material using differential scanning calorimetry and dynamic mechanical analysis. Temperatures for additional thermal exposure aging will be selected following the thermal analysis to avoid transitions in accelerated laboratory aging that do not occur in field conditions. Aging temperatures above thermal transitions may also be targeted to investigate the potential for artifacts in lifetime prediction from rapid accelerated aging. Total gamma doses and dose rates targeted for each material

  12. THz-wave generation via stimulated polariton scattering in KTiOAsO4 crystal.

    Science.gov (United States)

    Wang, Weitao; Cong, Zhenhua; Liu, Zhaojun; Zhang, Xingyu; Qin, Zengguang; Tang, Guanqi; Li, Ning; Zhang, Yuangeng; Lu, Qingming

    2014-07-14

    A terahertz parametric oscillator based on KTiOAsO(4) crystal is demonstrated for the first time. With the near-forward scattering configuration X(ZZ)X + Δφ, the polarizations of the pump, the Stokes and the generated THz waves are parallel to the z-axis of the crystal KTA. When the incident angle θext of the pump wave is changed from 1.875° to 6.500°, the THz wave is intermittently tuned from 3.59 to 3.96 THz, from 4.21 to 4.50 THz, from 4.90 to 5.16 THz, from 5.62 to 5.66 THz and from 5.92 to 6.43 THz. The obtained maximum THz wave energy is 627 nJ at 4.30 THz with a pump energy of 100 mJ. It is believed that the terahertz wave generation is caused by the stimulated scattering of the polaritons associated with the most intensive transverse A(1) mode of 233.8 cm(-1). Four much weaker transverse A(1) modes of 132.9 cm(-1), 156.3 cm(-1),175.1 cm(-1), and 188.4 cm(-1) cause four frequency gaps, from 3.97 THz to 4.20 THz, from 4.51 to 4.89 THz, from 5.17 to 5.61 THz and from 5.67 to 5.91 THz, respectively.

  13. Generation of green frequency comb from chirped χ{sup (2)} nonlinear photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Lai, C.-M. [Department of Electronic Engineering, Ming Chuan University, Taoyuan, Taiwan (China); Chang, K.-H.; Yang, Z.-Y.; Fu, S.-H.; Tsai, S.-T.; Hsu, C.-W.; Peng, L.-H. [Department of Electrical Engineering and Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, Taiwan (China); Yu, N. E. [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Boudrioua, A. [LPL, CNRS - UMR 7538, Université Paris 13, Sorbone Paris Cité (France); Kung, A. H. [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan (China); Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, Taiwan (China)

    2014-12-01

    Spectrally broad frequency comb generation over 510–555 nm range was reported on chirped quasi-phase-matching (QPM) χ{sup (2)} nonlinear photonic crystals of 12 mm length with periodicity stepwise increased from 5.9 μm to 7.1 μm. When pumped with nanosecond infrared (IR) frequency comb derived from a QPM optical parametric oscillator (OPO) and spanned over 1040 nm to 1090 nm wavelength range, the 520 nm to 545 nm up-converted green spectra were shown to consist of contributions from (a) second-harmonic generation among the signal or the idler modes, and (b) sum-frequency generation (SFG) from the neighboring pairs of the signal or the idler modes. These mechanisms led the up-converted green frequency comb to have the same mode spacing of 450 GHz as that in the IR-OPO pump comb. As the pump was further detuned from the aforementioned near-degeneracy point and moved toward the signal (1020–1040 nm) and the idler (1090–1110 nm) spectral range, the above QPM parametric processes were preserved in the chirped QPM devices to support up-converted green generation in the 510–520 nm and the 545–555 nm spectral regime. Additional 530–535 nm green spectral generation was also observed due to concurrence of multi-wavelength SFG processes between the (signal, idler) mode pairs. These mechanisms facilitate the chirped QPM device to support a single-pass up-conversion efficiency ∼10% when subject to an IR-OPO pump comb with 200 mW average power operated near- or off- the degeneracy point.

  14. Fifth generation computer systems. Proceedings of the International conference

    Energy Technology Data Exchange (ETDEWEB)

    Moto-oka, T

    1982-01-01

    The following topics were dealt with: Fifth Generation Computer Project-social needs and impact; knowledge information processing research plan; architecture research plan; knowledge information processing topics; fifth generation computer architecture considerations.

  15. IMECCHI-DATANETWORK: empowering knowledge generation through international data network

    Directory of Open Access Journals (Sweden)

    Marie Annick Le Pogam

    2017-04-01

    Within the IMECCHI-DATANETWORK initiative, databases from various countries will be locally converted in a CDM which will facilitate study replication in a distributed fashion while granting interoperability across coding systems. Through such international data networks, data are empowered for creating results which are generalizable to multiple countries. Cross-border data sharing and international comparisons are also facilitated.

  16. Extension of supercontinuum spectrum generated in photonic crystal fiber by using chirped femtosecond pulses

    Science.gov (United States)

    Vengelis, Julius; Jarutis, Vygandas; Sirutkaitis, Valdas

    2017-08-01

    We present results of experimental and numerical investigation of supercontinuum generation in polarization maintaining photonic crystal fiber (PCF) using chirped femtosecond pulses. The initial unchirped pump pulse source was a mode-locked Yb:KGW laser generating 52 nJ energy 110 fs duration pulses at 1030 nm with 76 MHz repetition rate. The nonlinear medium was a 32 cm long polarization maintaining PCF manufactured by NKT Photonics A/S. We demonstrated the influence of pump pulse chirp on spectral characteristics of supercontinuum. We showed that by chirping pump pulses positively or negatively one can obtain broader supercontinuum spectrum than in case of unchirped pump pulses at the same peak power. Moreover, the extension can be controlled by changing the amount of pump pulse chirp. In our case the supercontinuum spectrum width was extended by up to 115 nm (at maximum chirp value of +10500 fs2 that we could achieve in our setup) compared to the case of unchirped pump at the same peak power.

  17. Soliton generation via continuous stokes acoustic self-scattering of hypersonic waves in a paramagnetic crystal

    International Nuclear Information System (INIS)

    Bugay, A. N.; Sazonov, S. V.

    2008-01-01

    A new mechanism is proposed for continuous frequency down-conversion of acoustic waves propagating in a paramagnetic crystal at a low temperature in an applied magnetic field. A transverse hypersonic pulse generating a carrier-free longitudinal strain pulse via nonlinear effects is scattered by the generated pulse. This leads to a Stokes shift in the transverse hypersonic wave proportional to its intensity, and both pulses continue to propagate in the form of a mode-locked soliton. As the transverse-pulse frequency is Stokes shifted, its spectrum becomes narrower. This process can be effectively implemented only if the linear group velocity of the transverse hypersonic pulse equals the phase velocity of the longitudinal strain wave. These velocities are renormalized by spin-phonon coupling and can be made equal by adjusting the magnitude of the applied magnetic field. The transverse structure of the soliton depends on the sign of the group velocity dispersion of the transverse component. When the dispersion is positive, planar solitons can develop whose transverse component has a topological defect of dark vortex type and longitudinal component has a hole. In the opposite case, the formation of two-component acoustic 'bullets' or vortices localized in all directions is possible

  18. Photoluminescence from a Tb-doped photonic crystal microcavity for white light generation

    International Nuclear Information System (INIS)

    Li Yigang; Almeida, Rui M

    2010-01-01

    Terbium-doped one-dimensional triple microcavities have been prepared by sol-gel processing. The photoluminescence (PL) of Tb 3+ ions outside a microcavity structure, when excited by blue laser light at 488 nm, consisted of three distinct peaks at 542, 587 and 619 nm. When embedded in the microcavities, the three Tb 3+ PL peaks were enhanced, balanced and broadened by the photonic crystal structure and combined into a continuous broad band. An analysis in the CIE colour space showed that white light can be obtained by mixing the modified Tb 3+ PL with the blue exciting light, while this is impossible with the original PL profile. This novel technique may improve white light generation by enhancing and modifying the spontaneous emission of current phosphors. It may also lead to the development of new rare-earth phosphor materials based on 4f-4f transitions, able to generate white light more efficiently, via simpler and cheaper alternatives to the current phosphor compositions. A novel configuration to combine this kind of structure with a white light-emitting-diode (LED) is also proposed.

  19. Two Octaves Supercontinuum Generation in Lead-Bismuth Glass Based Photonic Crystal Fiber

    Directory of Open Access Journals (Sweden)

    Ryszard Buczynski

    2014-06-01

    Full Text Available In this paper we report a two octave spanning supercontinuum generation in a bandwidth of 700–3000 nm in a single-mode photonic crystal fiber made of lead-bismuth-gallate glass. To our knowledge this is the broadest supercontinuum reported in heavy metal oxide glass based fibers. The fiber was fabricated using an in-house synthesized glass with optimized nonlinear, rheological and transmission properties in the range of 500–4800 nm. The photonic cladding consists of 8 rings of air holes. The fiber has a zero dispersion wavelength (ZDW at 1460 nm. Its dispersion is determined mainly by the first ring of holes in the cladding with a relative hole size of 0.73. Relative hole size of the remaining seven rings is 0.54, which allows single mode performance of the fiber in the infrared range and reduces attenuation of the fundamental mode. The fiber is pumped into anomalous dispersion with 150 fs pulses at 1540 nm. Observed spectrum of 700–3000 nm was generated in 2 cm of fiber with pulse energy below 4 nJ. A flatness of 5 dB was observed in 950–2500 nm range.

  20. Flexible, ferroelectric nanoparticle doped polymer dispersed liquid crystal devices for lower switching voltage and nanoenergy generation

    Science.gov (United States)

    Nimmy John, V.; Varanakkottu, Subramanyan Namboodiri; Varghese, Soney

    2018-06-01

    Flexible polymer dispersed liquid crystal (F-PDLC) devices were fabricated using transparent conducting ITO/PET film. Polymerization induced phase separation (PIPS) method was used for pure and ferroelectric BaTiO3 (BTO) and ZnO doped PDLC devices. The distribution of nanoparticles in the PDLC and the formation of micro cavities were studied using field emission scanning electron microscopy (FESEM). It was observed that the addition of ferroelectric BTO nanoparticles has reduced the threshold voltage (Vth) and saturation voltage (Vsat) of FNP-PDLC by 85% and 41% respectively due to the spontaneous polarization of ferroelectric nanoparticles. The ferroelectric properties of BTO and ZnO in the fabricated devices were investigated using dynamic contact electrostatic force microscopy (DC EFM). Flexing the device can generate a potential due to the piezo-tribo electric effect of the ferroelectric nanomaterial doped in the PDLC matrix, which could be utilized as an energy generating system. The switching voltage after multiple flexing was also studied and found to be in par with non-flexing situations.

  1. RADCHARM++: A C++ routine to compute the electromagnetic radiation generated by relativistic charged particles in crystals and complex structures

    Energy Technology Data Exchange (ETDEWEB)

    Bandiera, Laura; Bagli, Enrico; Guidi, Vincenzo [INFN Sezione di Ferrara and Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Ferrara, Via Saragat 1, 44121 Ferrara (Italy); Tikhomirov, Victor V. [Research Institute for Nuclear Problems, Belarusian State University, Minsk (Belarus)

    2015-07-15

    The analytical theories of coherent bremsstrahlung and channeling radiation well describe the process of radiation generation in crystals under some special cases. However, the treatment of complex situations requires the usage of a more general approach. In this report we present a C++ routine, named RADCHARM++, to compute the electromagnetic radiation emitted by electrons and positrons in crystals and complex structures. In the RADCHARM++ routine, the model for the computation of e.m. radiation generation is based on the direct integration of the quasiclassical formula of Baier and Katkov. This approach allows one taking into account real trajectories, and thereby the contribution of incoherent scattering. Such contribution can be very important in many cases, for instance for electron channeling. The generality of the Baier–Katkov operator method permits one to simulate the electromagnetic radiation emitted by electrons/positrons in very different cases, e.g., in straight, bent and periodically bent crystals, and for different beam energy ranges, from sub-GeV to TeV and above. The RADCHARM++ routine has been implemented in the Monte Carlo code DYNECHARM++, which solves the classical equation of motion of charged particles traveling through a crystal under the continuum potential approximation. The code has proved to reproduce the results of experiments performed at the MAinzer MIkrotron (MAMI) with 855 MeV electrons and has been used to predict the radiation spectrum generated by the same electron beam in a bent crystal.

  2. A novel method of generating and remembering international morse codes

    Digital Repository Service at National Institute of Oceanography (India)

    Charyulu, R.J.K.

    untethered communications have been advanced, despite as S.O.S International Morse Code will be at rescue as an emergency tool, when all other modes fail The details of hte method and actual codes have been enumerated....

  3. Progress of international cooperation of nuclear power generation

    International Nuclear Information System (INIS)

    Sasaki, Sadaaki; Ishikawa, Hidetaka; Eda, Hisao; Noda, Hiroshi; Kobayashi, Ichiro; Kawahara, Akira; Nagano, Akira

    1999-01-01

    International cooperation on nuclear power technology under promotion of the Japan Electric Power Information Center can be divided roughly to two items: one is an assistant project of Japan Keirin Association and another is an international training of operation management and so forth on nuclear power plant trusted by Ministry of International Trade and Industry. Among upgrading needs of technical cooperation on nuclear power to the developing nations, the electric companies were received a request on private cooperation by the Ministry of International Trade and Industry. In 1985, it was decided that the nuclear power technical cooperation through an subsidy project of the Japan Keirin Association was advanced mainly by every electric companies as a window of the Japan Electric Power Information Center in Japan Electric Industry Association. And, by receiving another request, the Japan Electric Power Information Center began an international training on operation management and so one of the nuclear power plant since October, 1992. Here were introduced outlines of both technical cooperation on nuclear power and international training on operation management. (G.K.)

  4. A Thermoelectric Generator Replacing Radiator for Internal Combustion Engine Vehicles

    Directory of Open Access Journals (Sweden)

    Shiho Kim

    2011-12-01

    Full Text Available We have proposed and developed a low temperature thermoelectric generator (TEG using engine water coolant of light-duty vehicles. Experimental results from test vehicle, of which engine size is about 2.0 liters, show that fabricated prototype Thermoelectric Generator generates more than 75W for driving condition of 80 km/hour, and output power is about 28W during idle condition. The proposed TEG can replace conventional radiator without additional water pumps or mechanical devices except for basic components of legacy water cooling system of radiator.

  5. Chiral crystal of a C2v-symmetric 1,3-diazaaulene derivative showing efficient optical second harmonic generation

    KAUST Repository

    Ma, Xiaohua; Fu, Limin; Zhao, Yunfeng; Ai, Xicheng; Zhang, Jianping; Han, Yu; Guo, Zhixin

    2011-01-01

    the moderate static first hyperpolarizabilities (β0) for both APNA [(136 ± 5) à - 10-30 esu] and DPAPNA [(263 ± 20) à - 10-30 esu], only APNA crystal shows a powder efficiency of second harmonic generation (SHG) of 23 times that of urea. It is shown

  6. 78 FR 79709 - Duke Energy Florida, Inc., Crystal River Unit 3 Nuclear Generating Plant Post-Shutdown...

    Science.gov (United States)

    2013-12-31

    ... NUCLEAR REGULATORY COMMISSION [Docket No. 50-302; NRC-2013-0283] Duke Energy Florida, Inc., Crystal River Unit 3 Nuclear Generating Plant Post-Shutdown Decommissioning Activities Report AGENCY: Nuclear Regulatory Commission (NRC). ACTION: Notice of receipt; availability; public meeting; and request...

  7. The Next Generation Information Infrastructure for International Trade

    DEFF Research Database (Denmark)

    Henningsson, Stefan; Gal, Uri; Bjørn-Andersen, Niels

    2011-01-01

    that are in control of their business. Trusted traders are entitled to trade facilitations, faster border crossing, and fewer physical inspections. To enable the use of trusted traders, changes are required to the information infrastructure (II) of international trade. This article complements existing works on e......-Government interoperability by a theoretically driven approach with theoretical development of the II concept and how II can be modified as additional focus. Following the principles of IS design research, this paper presents a design proposition for the II of international trade. Using theories of II development and change......Regulators and actors in international trade are facing a difficult challenge of increasing control and security while at the same time lowering the administrative burden for traders. As a tentative response, the European Commission has introduced the concept of “trusted traders”: certified traders...

  8. Virtual Seafloor Reduces Internal Wave Generation by Tidal Flow

    Science.gov (United States)

    Zhang, Likun; Swinney, Harry L.

    2014-03-01

    Our numerical simulations of tidal flow of a stratified fluid over periodic knife-edge ridges and random topography reveal that the time-averaged tidal energy converted into internal gravity wave radiation arises only from the section of a ridge above a virtual seafloor. The average radiated power is approximated by the power predicted by linear theory if the height of the ridge is measured relative to the virtual floor. The concept of a virtual floor can extend the applicability of linear theory to global predictions of the conversion of tidal energy into internal wave energy in the oceans.

  9. New methods of highly efficient controlled generation of radiation by liquid crystal nanostructures in a wide spectral range

    International Nuclear Information System (INIS)

    Bagayev, S N; Klementyev, V M; Nyushkov, B N; Pivtsov, V S; Trashkeev, S I

    2012-01-01

    We report the recent results of research focused on a new kind of soft matter-the liquid-crystal nanocomposites with controllable mechanical and nonlinear optical properties. These are promising media for implementation of ultra-compact photonic devices and efficient sources of coherent radiation in a wide spectral range. We overview the technology of preparation of nematic-liquid-crystal media saturated with disclination defects. The defects were formed in different ways: by embedding nanoparticles and molecular objects, by exposure to alpha-particle flux. The defect locations were controlled by applying an electric field. We also present and discuss the recently discovered features of nematic-liquid-crystal media: a thermal orientation effect leading to the fifth-order optical nonlinearity, enormous second-order susceptibility revealed by measurements, and structural changes upon exposure to laser radiation. We report on efficient generation of harmonics, sum and difference optical frequencies in nematic-liquid-crystal media. In addition, transformation of laser radiation spectra to spectral supercontinua, and filamentation of laser beams were also observed in nematic-liquid-crystal media. We conclude that most nonlinear optical effects result from changes of the orientational order in the examined nematic liquid crystals. These changes lead to the symmetry breaking and disclination appearances.

  10. Invited Article: Multiple-octave spanning high-energy mid-IR supercontinuum generation in bulk quadratic nonlinear crystals

    Directory of Open Access Journals (Sweden)

    Binbin Zhou

    2016-08-01

    Full Text Available Bright and broadband coherent mid-IR radiation is important for exciting and probing molecular vibrations. Using cascaded nonlinearities in conventional quadratic nonlinear crystals like lithium niobate, self-defocusing near-IR solitons have been demonstrated that led to very broadband supercontinuum generation in the visible, near-IR, and short-wavelength mid-IR. Here we conduct an experiment where a mid-IR crystal is pumped in the mid-IR. The crystal is cut for noncritical interaction, so the three-wave mixing of a single mid-IR femtosecond pump source leads to highly phase-mismatched second-harmonic generation. This self-acting cascaded process leads to the formation of a self-defocusing soliton at the mid-IR pump wavelength and after the self-compression point multiple octave-spanning supercontinua are observed. The results were recorded in a commercially available crystal LiInS2 pumped in the 3-4 μm range with 85 fs 50 μJ pulse energy, with the broadest supercontinuum covering 1.6-7.0 μm. We measured up 30 μJ energy in the supercontinuum, and the energy promises to scale favorably with an increased pump energy. Other mid-IR crystals can readily be used as well to cover other pump wavelengths and target other supercontinuum wavelength ranges.

  11. Chiral crystal of a C2v-symmetric 1,3-diazaaulene derivative showing efficient optical second harmonic generation

    KAUST Repository

    Ma, Xiaohua

    2011-03-01

    Achiral nonlinear optical (NLO) chromophores 1,3-diazaazulene derivatives, 2-(4â€-aminophenyl)-6-nitro-1,3-diazaazulene (APNA) and 2-(4â€-N,N-diphenylaminophenyl)-6-nitro-1,3-diazaazulene (DPAPNA), were synthesized with high yield. Despite the moderate static first hyperpolarizabilities (β0) for both APNA [(136 ± 5) à - 10-30 esu] and DPAPNA [(263 ± 20) à - 10-30 esu], only APNA crystal shows a powder efficiency of second harmonic generation (SHG) of 23 times that of urea. It is shown that the APNA crystallization driven cooperatively by the strong H-bonding network and the dipolar electrostatic interactions falls into the noncentrosymmetric P2 12121 space group, and that the helical supramolecular assembly is solely responsible for the efficient SHG response. To the contrary, the DPAPNA crystal with centrosymmetric P-1 space group is packed with antiparalleling dimmers, and is therefore completely SHG-inactive. 1,3-Diazaazulene derivatives are suggested to be potent building blocks for SHG-active chiral crystals, which are advantageous in high thermal stability, excellent near-infrared transparency and high degree of designing flexibility. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011 Optical crystals based on 1,3-diazaazulene derivatives are reported as the first example of organic nonlinear optical crystal whose second harmonic generation activity is found to originate solely from the chirality of their helical supramolecular orientation. The strong H-bond network forming between adjacent choromophores is found to act cooperatively with dipolar electrostatic interactions in driving the chiral crystallization of this material. Copyright © 2011 Wiley Periodicals, Inc.

  12. Summaries of reports of XLII International Tulinov conference on physics of interactions of charged particles with crystals

    International Nuclear Information System (INIS)

    Panasyuk, M.I.

    2012-01-01

    The XLII International Tulinov conference on physics of interactions of charged particles with crystals took place in Moscow 29-31 May 2012. The collection contains theses of the reports on the following directions: the physics of orientation effects; radiation of electrons and positrons in solids; scattering, sputtering and secondary particle emission; modification and analysis of surface [ru

  13. Generation of Light Scattering States in Cholesteric Liquid Crystals by Optically Controlled Boundary Conditions

    Directory of Open Access Journals (Sweden)

    Timothy J. Bunning

    2013-03-01

    Full Text Available Circularly polarized light was previously employed to stimulate the reversible and reconfigurable writing of scattering states in cholesteric liquid crystal (CLC cells constructed with a photosensitive layer. Such dynamic photodriven responses have utility in remotely triggering changes in optical constructs responsive to optical stimulus and applications where complex spatial patterning is required. Writing of scattering regions required the handedness of incoming radiation to match the handedness of the CLC and the reflection bandwidth of the CLC to envelop the wavelength of the incoming radiation. In this paper, the mechanism of transforming the CLC into a light scattering state via the influence of light on the photosensitive alignment layer is detailed. Specifically, the effects of: (i the polarization state of light on the photosensitive alignment layer; (ii the exposure time; and (iii the incidence angle of radiation on domain formation are reported. The photogenerated light-scattering domains are shown to be similar in appearance between crossed polarizers to a defect structure that occurs at a CLC/air interface (i.e., a free CLC surface. This observation provides strong indication that exposure of the photosensitive alignment layer to the circularly polarized light of appropriate wavelength and handedness generates an out-of-plane orientation leading to a periodic distortion of the original planar structure.

  14. Supercontinuum generation in silicon nanowire embedded photonic crystal fibers with different core geometries

    Science.gov (United States)

    Abdosllam, M. Abobaker; Gunasundari, E.; Senthilnathan, K.; Sivabalan, S.; Nakkeeran, K.; Ramesh Babu, P.

    2014-07-01

    We design various silicon nanowire embedded photonic crystal fibers (SN-PCFs) with different core geometries, namely, circular, rectangular and elliptical using finite element method. Further, we study the optical properties such as group velocity dispersion (GVD), third order dispersion (TOD) of x and y-polarized modes and effective nonlinearity for a wavelength range from 0.8 to 1.6 μm. The proposed structure exhibits almost flat GVD (0.8 to 1.2 μm wavelength), zero GVD (≍ 1.31 μm) and small TOD (0.00069 ps3/m) at 1.1 μm wavelength and high nonlinearity (2916 W-1m-1) at 0.8 μm wavelength for a 300 nm core diameter of circular core SN-PCF. Besides, we have been able to demonstrate the supercontinuum for the different core geometries at 1.3 μm wavelength with a less input power of 25 W for the input pulse of 20 fs. The numerical simulation results reveal that the proposed circular core SN-PCF could generate the supercontinuum of wider bandwidth (900 nm) compared to that from rest of the geometries. This enhanced bandwidth turns out to be a boon for optical coherence tomography (OCT) system.

  15. Does the internet generate economic growth, international trade, or both?

    OpenAIRE

    Meijers, Huub

    2012-01-01

    Recent cross country panel data studies find a positive impact of internet use on economic growth and a positive impact of internet use on trade. The present study challenges the first finding by showing that internet use does not explain economic growth directly in a fully specified growth model. In particular openness to international trade variables seems to be highly correlated with internet use and the findings in the literature that internet use causes trade is confirmed here, suggestin...

  16. Highly nonlinear organic crystal OHQ-T for efficient ultra-broadband terahertz wave generation beyond 10 THz.

    Science.gov (United States)

    Kang, Bong Joo; Baek, In Hyung; Lee, Seung-Heon; Kim, Won Tae; Lee, Seung-Jun; Jeong, Young Uk; Kwon, O-Pil; Rotermund, Fabian

    2016-05-16

    We report on efficient generation of ultra-broadband terahertz (THz) waves via optical rectification in a novel nonlinear organic crystal with acentric core structure, i.e. 2-(4-hydroxystyryl)-1-methylquinolinium 4-methylbenzenesulfonate (OHQ-T), which possesses an ideal molecular structure leading to a maximized nonlinear optical response for near-infrared-pumped THz wave generation. By systematic studies on wavelength-dependent phase-matching conditions in OHQ-T crystals of different thicknesses we are able to generate coherent THz waves with a high peak-to-peak electric field amplitude of up to 650 kV/cm and an upper cut-off frequency beyond 10 THz. High optical-to-THz conversion efficiency of 0.31% is achieved by efficient index matching with a selective pumping at 1300 nm.

  17. G20: Engaging with International Organizations to Generate Growth

    Directory of Open Access Journals (Sweden)

    Marina Larionova

    2017-08-01

    Full Text Available Born in response to economic and financial crises which existing institutions were unable to address adequately, the G20 transformed from a crisis management group into the premier forum for international economic cooperation. Like its predecessor, the G7 (which was set up in 1975, and BRICS (established in 2009, G20 is an informal club or summit institution. To ensure continuity, legitimacy and efficiency in fulfilling their global governance functions of deliberation, direction-setting, decision-making, delivery and the development of global governance, the G20 members engage other international organizations. It is hypothesized that to maximize benefits from its engagement with international organizations, the G20 resorts to a combination of the “catalyst”, “core group” and “parallel treatment” approaches exercised by summit institutions. These include exerting an influence in promoting changes to international organizations through endorsement or stimulus, compelling them to reform, imparting a new direction by giving a lead that the other organizations would follow, and creating original mechanisms, working in parallel with existing institutions. The article tests this assumption. To trace the dynamics of G20 engagement with multilateral organizations and identify preferred models across the presidencies and policy areas, the analysis is carried out within the rational choice institutionalist paradigm, drawing on the quantitative and qualitative analysis of documents adopted by the G20. Findings from the study indicate that the intensity of the G20 engagement with the IOs is very high and G20 mostly resorts to a combination of the catalyst and core group approaches, though the pattern depends on the policy area, the IOs and the presidency agenda. The intensity of G20 engagement with the IMF, Financial Stability Board, World Bank, and Organization for Economic Co-operation and Development by far exceeds the intensity of its

  18. Fabrication and Characterization of Three Dimensional Photonic Crystals Generated by Multibeam Interference Lithography

    Science.gov (United States)

    Chen, Ying-Chieh

    2009-01-01

    Multibeam interference lithography is investigated as a manufacturing technique for three-dimensional photonic crystal templates. In this research, optimization of the optical setup and the photoresist initiation system leads to a significant improvement of the optical quality of the crystal, as characterized by normal incidence optical…

  19. Biomass Gasification for Power Generation Internal Combustion Engines. Process Efficiency

    International Nuclear Information System (INIS)

    Lesme-Jaén, René; Garcia-Faure, Luis; Oliva-Ruiz, Luis; Pajarín-Rodríguez, Juan; Revilla-Suarez, Dennis

    2016-01-01

    Biomass is a renewable energy sources worldwide greater prospects for its potential and its lower environmental impact compared to fossil fuels. By different processes and energy conversion technologies is possible to obtain solid, liquid and gaseous fuels from any biomass.In this paper the evaluation of thermal and overall efficiency of the gasification of Integral Forestry Company Santiago de Cuba is presented, designed to electricity generation from waste forest industry. The gasifier is a downdraft reactor, COMBO-80 model of Indian manufacturing and motor (diesel) model Leyland modified to work with producer gas. The evaluation was conducted at different loads (electric power generated) of the motor from experimental measurements of flow and composition of gas supplied to the engine. The results show that the motor operates with a thermal efficiency in the range of 20-32% with an overall efficiency between 12-25 %. (author)

  20. Network integration of distributed generation: international research and development

    Energy Technology Data Exchange (ETDEWEB)

    Watson, J.

    2003-07-01

    This report provides information on privately and publicly funded research and development programmes in distributed generation (DG) in the USA, the European Union and Japan. Protection systems for the installation of DG, power electronics for the connection of DG to electricity distribution systems, reliability modelling, power quality issues, connection standards, and simulation and computer modelling are examined. The relevance of the programmes to the UK is considered.

  1. Analysis of the internal heat losses in a thermoelectric generator

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Christensen, Dennis Valbjørn; Eriksen, Dan

    2014-01-01

    and radiative heat losses, including surface to surface radiation. For radiative heat losses it is shown that for the temperatures considered here, surface to ambient radiation is a good approximation of the heat loss. For conductive heat transfer the module efficiency is shown to be comparable to the case...... of radiative losses. Finally, heat losses due to internal natural convection in the module is shown to be negligible for the millimetre sized modules considered here. The combined case of radiative and conductive heat transfer resulted in the lowest efficiency. The optimized load resistance is found...... to decrease for increased heat loss. The leg dimensions are varied for all heat losses cases and it is shown that the ideal way to construct a TEG module with minimal heat losses and maximum efficiency is to either use a good insulating material between the legs or evacuate the module completely, and use...

  2. Electronic Commerce – An International Phenomenon, Generating Commercial Litigations

    Directory of Open Access Journals (Sweden)

    Angelica Roşu

    2012-05-01

    Full Text Available Although the e-commerce boom of the past few years has produced plenty of satisfied e-shoppersand successful Web-based companies, many consumers and businesses are left wondering where they can goto resolve their online disputes. The legal system (such as the court system and classical arbitration cannoteffectively respond to the challenges posed by conducting electronic commerce and this paper is proposed toanalyse the types of disputes that can arise from those e-commerce operations. The aim of this approach isrepresented by our attempt to explain why conflict resolution cannot be reasonably accomplished usingtraditional legal system and consequently the measures that have been taken by the international bodies tofacilitate consumers' right to a fair and effective trial services.

  3. Thermal resistance of a convectively cooled plate with applied heat flux and variable internal heat generation

    International Nuclear Information System (INIS)

    Venkataraman, N.S.; Cardoso, H.P.; Oliveira Filho, O.B. de

    1981-01-01

    The conductive heat transfer in a rectangular plate with nonuniform internal heat generation, with one end convectively cooled and a part of the opposite end subjected to external heat flux is considered. The remaining part of this end as well as the other two sides are thermally insulated. The governing differential equation is solved by a finite difference scheme. The variation of the thermal resistance with Biot modulus, the plate geometry, the internal heat generation parameter and the type of profile of internal heat generation is discussed. (author) [pt

  4. Report on the international workshop on next generation linear colliders

    International Nuclear Information System (INIS)

    Ruth, R.D.

    1989-05-01

    Many laboratories around the world have begun vigorous research programs on a next generation linear collider (NLC). However, it has been recognized that the research towards NLC is beyond the capabilities of any one laboratory presently. This workshop was organized to begin a series of workshops that address this problem. Specifically, the main goals of the workshop were to discuss research programs of the various laboratories around the world, to identify common areas of interest in the various NLC designs, and finally to advance these programs by collaboration. The particular topics discussed briefly in this paper are: parameters, rf power, structures, final focus, beam dynamics, damping rings, and instrumentation. 2 refs., 3 figs., 6 tabs

  5. Inspiring the Next Generation: The International Space Station Education Accomplishments

    Science.gov (United States)

    Alleyne, Camille W.; Hasbrook, Pete; Knowles, Carolyn; Chicoine, Ruth Ann; Miyagawa, Yayoi; Koyama, Masato; Savage, Nigel; Zell, Martin; Biryukova, Nataliya; Pinchuk, Vladimir; hide

    2014-01-01

    The International Space Station (ISS) has a unique ability to capture the imagination of both students and teachers worldwide. Since 2000, the presence of humans onboard ISS has provided a foundation for numerous educational activities aimed at capturing that interest and motivating study in the sciences, technology, engineering and mathematics (STEM). Over 43 million students around the world have participated in ISS-related educational activities. Projects such as YouTube Space Lab, Sally Ride Earth Knowledge-based Acquired by Middle Schools (EarthKAM), SPHERES (Synchronized Position Hold Engage and Reorient Experimental Satellites) Zero-Robotics, Tomatosphere, and MAI-75 events among others have allowed for global student, teacher and public access to space through student classroom investigations and real-time audio and video contacts with crewmembers. Educational activities are not limited to STEM but encompass all aspects of the human condition. This is well illustrated in the Uchu Renshi project, a chain poem initiated by an astronaut while in space and continued and completed by people on Earth. With ISS operations now extended to 2024, projects like these and their accompanying educational materials are available to more students around the world. From very early on in the program's history, students have been provided with a unique opportunity to get involved and participate in science and engineering projects. Many of these projects support inquiry-based learning that allows students to ask questions, develop hypothesis-derived experiments, obtain supporting evidence and identify solutions or explanations. This approach to learning is well-published as one of the most effective ways to inspire students to pursue careers in scientific and technology fields. Ever since the first space station element was launched, a wide range of student experiments and educational activities have been performed, both individually and collaboratively, by all the

  6. Short pulse generation in a passively mode-locked photonic crystal semiconductor laser

    DEFF Research Database (Denmark)

    Heuck, Mikkel; Blaaberg, Søren; Mørk, Jesper

    2010-01-01

    We present a new type of passively mode-locked laser with quantum wells embedded in photonic crystal waveguides operating in the slow light regime, which is capable of emitting sub picosecond pulses with widely controllable properties......We present a new type of passively mode-locked laser with quantum wells embedded in photonic crystal waveguides operating in the slow light regime, which is capable of emitting sub picosecond pulses with widely controllable properties...

  7. Internally generated natural variability of global-mean temperatures

    International Nuclear Information System (INIS)

    Wigley, T.M.L.; Raper, S.C.B.

    1990-01-01

    Quantitative frequency-domain and time-domain estimates are made of an important aspect of natural variability of global-mean temperatures, namely, passive internal variability resulting from the modulation of atmospheric variability by the ocean. The results are derived using an upwelling-diffusion, energy-balance climate model. In the frequency domain, analytical spectral results show a transition from a high-frequency region in which the response is determined by the mixed-layer heat capacity and is independent of the climate sensitivity (time scales less than around 10 years), to a low-frequency region in which the response depends only on the climate sensitivity. In the former region the spectral power is proportional to f -2 , where f is the frequency, while in the latter the power is independent of frequency. The range of validity of these results depends on the components of the climate system that are included in the model. In this case these restrict the low-frequency results to time scales less than about 1,000 years. A qualitative extrapolation is presented in an attempt to explain the observed low-frequency power spectra from deep-sea-core δ 18 O time series. The spectral results are also used to estimate the effective heat capacity of the ocean as a function of frequency. At low frequencies, this can range up to 50 times greater than the heat capacity of the mixed layer. Results in the time domain are obtained by solving the model equations numerically

  8. Voltage-Controlled Quantum Dynamics and Generation Entanglement between Two Separated Quantum-Dot Molecules Embedded in Photonic Crystal Cavities

    International Nuclear Information System (INIS)

    Cheng Mu-Tian; Song Yan-Yan; Ma Xiao-San; Wang Xia

    2014-01-01

    Voltage-controlled quantum dynamics of two quantum-dot molecules (QDMs) embedded in two separated photonic crystal cavities are theoretically investigated. We show numerically that generation of entangled states and population transfer between the two QDMs can be realized with the same coupling parameters. The effects of parameters deviation and dissipations on generation entangled states and populations transfer are also discussed. The results may be used for realization of new-type of solid state quantum devices and integrated electro-optical devices

  9. Summaries of reports of XLIII International Tulinov conference on physics of interactions of charged particles with crystals

    International Nuclear Information System (INIS)

    Panasyuk, M.I.

    2013-01-01

    The collection contains summaries of reports of the XLIII International Tulinov conference on physics of interactions of charged particles with crystals. The problems of physics of orientation effects are considered. The recent results of investigations of electrons and positrons radiation in solids are presented. The problems of scattering, sputtering and emission of secondary particles are discussed. The particular attention is given to modification of materials surfaces by means of charged particles [ru

  10. Influence of temperature rise distribution in second harmonic generation crystal on intensity distributions of output second harmonic wave

    International Nuclear Information System (INIS)

    Li Wei; Feng Guoying; Li Gang; Huang Yu; Zhang Qiuhui

    2009-01-01

    Second-harmonic generation (SHG) of high-intensity laser with an SHG crystal for type I angle phase matching has been studied by the use of a split-step algorithm based on the fast Fourier transform and a fourth-order Runge-Kutta (R-K) integrator. The transverse walk-off effect, diffraction, the second-order and the third-order nonlinear effects have been taken into consideration. Influences of a temperature rise distribution of the SHG crystal on the refractive indices of ordinary wave and extraordinary wave have been discussed. The rules of phase mismatching quantity, intensity distribution of output beam and frequency conversion efficiency varying with the temperature rise distribution of the SHG crystal have been analyzed quantitatively. The calculated results indicate that in a high power frequency conversion system, the temperature rise distribution of SHG crystal would result in the phase mismatching of fundamental and harmonic waves, leading to the variation of intensity distribution of the output beam and the decrease of the conversion efficiency. (authors)

  11. Ultrastable, high efficiency picosecond green light generation using K3B6O10Br series nonlinear optical crystals

    Science.gov (United States)

    Hou, Z. Y.; Xia, M. J.; Wang, L. R.; Xu, B.; Yan, D. X.; Meng, L. P.; Liu, L. J.; Xu, D. G.; Zhang, L.; Wang, X. Y.; Li, R. K.; Chen, C. T.

    2017-09-01

    Two perovskite-structure K3B6O10Br1-x Cl x (x  =  0 and 0.5) series nonlinear optical crystals were thoroughly investigated for their picosecond 532 nm laser pulses abilities and high power outputs were achieved via second harmonic generation (SHG) technique for the first time. SHG conversion efficiency of 57.3% with a 13.2 mm length K3B6O10Br (KBB) crystal was achieved using a laser source of pulse repetition rate of 10 Hz and pulse width of 25 ps, which is the highest conversion efficiency of ps visible laser based on KBB crystal. And by employing an 80 MHz, 10 ps fundamental laser beam, maximum power outputs of 12 W with K3B6O10Br0.5Cl0.5 (KBBC) and 11.86 W with KBB crystals were successfully demonstrated. Furthermore, the standard deviation jitters of the average power outputs are less than 0.6% and 1.17% by KBB and KBBC, respectively, showing ultrastable power stabilities favorable for practical applications. In addition, the other optical parameters including acceptance angle and temperature bandwidth were also investigated.

  12. On the generation and evolution of internal solitary waves in the southern Red Sea

    KAUST Repository

    Guo, Daquan

    2015-04-01

    Satellite observations recently revealed the existence of trains of internal solitary waves in the southern Red Sea between 16.0°N and 16.5°N, propagating from the centre of the domain toward the continental shelf [Da silva et al., 2012]. Given the relatively weak tidal velocity in this area and their generation in the central of the domain, Da Silva suggested three possible mechanisms behind the generation of the waves, namely Resonance and disintegration of interfacial tides, Generation of interfacial tides by impinging, remotely generated internal tidal beams and for geometrically focused and amplified internal tidal beams. Tide analysis based on tide stations data and barotropic tide model in the Red Sea shows that tide is indeed very weak in the centre part of the Red Sea, but it is relatively strong in the northern and southern parts (reaching up to 66 cm/s). Together with extreme steep slopes along the deep trench, it provides favourable conditions for the generation of internal solitary in the southern Red Sea. To investigate the generation mechanisms and study the evolution of the internal waves in the off-shelf region of the southern Red Sea we have implemented a 2-D, high-resolution and non-hydrostatic configuration of the MIT general circulation model (MITgcm). Our simulations reproduce well that the generation process of the internal solitary waves. Analysis of the model\\'s output suggests that the interaction between the topography and tidal flow with the nonlinear effect is the main mechanism behind the generation of the internal solitary waves. Sensitivity experiments suggest that neither tidal beam nor the resonance effect of the topography is important factor in this process.

  13. Studies on internal friction in electron-irradiated iron crystals after plastic deformation

    International Nuclear Information System (INIS)

    Wolf, J.

    1986-01-01

    For the analysis of atomic point defects in high-purity the generation of atomic point defects was, above all, carried out by electron radiation, but in addition, also by plastic deformation. The exposure to radiation was realized at different temperatures in the Dynamitron of the University of Stuttgart (80 K, 160 K) and also in the low-temperature radiation facility of the nuclear research plant (KfA) Juelich (50 K). The radiation doses ranged between 2.7.10 21 e - /m 2 and 1.0.10 23 e - /m 2 . In situ plastic deformation was achieved at about 80 K (torsion, 4%). Internal friction which was determined in an inverse torsion pendulum in the temperature range of 80 K - 700 K and at frequencies of about 1 Hz served as defect indicator. In this study simulation programs were developed which were to give information prior to the realization of measurements on the temperatures and the intensity of the damping peaks to be expected. The internal friction peaks measured in the framework of this study could be assigned to the recovery stages I-IV. The measured values were discussed for three temperature ranges with main emphasis on the investigation of the recovering, radiation-induced or deformation-induced, atomic point defect in the temperature range of the recovery stage III (200 K - 270 K). (orig./MM) [de

  14. Efficient Mid-Infrared Supercontinuum Generation in Tapered Large Mode Area Chalcogenide Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Petersen, Christian Rosenberg; Engelsholm, Rasmus Dybbro; Markos, Christos

    2017-01-01

    Mid-infrared supercontinuum spanning from 1.8-9  μm with an output power of 41.5 mW is demonstrated by pumping tapered large mode area chalcogenide photonic crystal fibers using a 4 μm optical parametric source.......Mid-infrared supercontinuum spanning from 1.8-9  μm with an output power of 41.5 mW is demonstrated by pumping tapered large mode area chalcogenide photonic crystal fibers using a 4 μm optical parametric source....

  15. Intercellular cancer collisions generate an ejected crystal comet tail effect with fractal interface embryoid body reassembly transformation

    International Nuclear Information System (INIS)

    Díaz, Jairo A; Murillo, Mauricio F; Barrero, Alvaro

    2011-01-01

    We have documented self-assembled geometric triangular chiral crystal complexes (GTCHC) and a framework of collagen vascular invariant geometric attractors in cancer tissues. This article shows how this system evolves in time. These structures are incorporated together and evolve in different ways. When the geometric core is stable, and the tissue architecture collapses, fragmented components emerge, which reveal a hidden interior identifying how each molecule is reassembled into the original mold, using one common connection, ie, a fractal self-similarity that guided the system from the beginning. GTCHC complexes generate ejected crystal comet tail effects and produce strange helicity states that arise in the form of spin domain interactions. As the crystal growth vibration stage progresses, biofractal echo images converge in a master-built construction of embryoid bodies with enolase-selective immunopositivity in relation to clusters of triangular chiral cell organization. In our electro-optic collision model, we were able to predict and replicate all the characteristics of this complex geometry that connects a physical phenomenon with the signal patterns that generate biologic chaos. Intrinsically, fractal geometry makes spatial correction errors embrace the chaotic system in a way that permits new structures to emerge, and as a result, an ordered self-assembly of embryoid bodies with neural differentiation at the final stage of cancer development is a predictable process. We hope that further investigation of these structures will lead not only to a new way of thinking about physics and biology, but also to a rewarding area in cancer research

  16. Lateralization of the posterior parietal cortex for internal monitoring of self- versus externally generated movements.

    Science.gov (United States)

    Ogawa, Kenji; Inui, Toshio

    2007-11-01

    Internal monitoring or state estimation of movements is essential for human motor control to compensate for inherent delays and noise in sensorimotor loops. Two types of internal estimation of movements exist: self-generated movements, and externally generated movements. We used functional magnetic resonance imaging to investigate differences in brain activity for internal monitoring of self- versus externally generated movements during visual occlusion. Participants tracked a sinusoidally moving target with a mouse cursor. On some trials, vision of either target (externally generated) or cursor (self-generated) movement was transiently occluded, during which subjects continued tracking by estimating current position of either the invisible target or cursor on screen. Analysis revealed that both occlusion conditions were associated with increased activity in the presupplementary motor area and decreased activity in the right lateral occipital cortex compared to a control condition with no occlusion. Moreover, the right and left posterior parietal cortex (PPC) showed greater activation during occlusion of target and cursor movements, respectively. This study suggests lateralization of the PPC for internal monitoring of internally versus externally generated movements, fully consistent with previously reported clinical findings.

  17. INTERNATIONAL STUDY OF ALUMINUM IMPACTS ON CRYSTALLIZATION IN U.S. HIGH LEVEL WASTE GLASS

    International Nuclear Information System (INIS)

    Fox, K; David Peeler, D; Tommy Edwards, T; David Best, D; Irene Reamer, I; Phyllis Workman, P; James Marra, J

    2008-01-01

    The objective of this task was to develop glass formulations for (Department of Energy) DOE waste streams with high aluminum concentrations to avoid nepheline formation while maintaining or meeting waste loading and/or waste throughput expectations as well as satisfying critical process and product performance related constraints. Liquidus temperatures and crystallization behavior were carefully characterized to support model development for higher waste loading glasses. The experimental work, characterization, and data interpretation necessary to meet these objectives were performed among three partnering laboratories: the V.G. Khlopin Radium Institute (KRI), Pacific Northwest National Laboratory (PNNL) and Savannah River National Laboratory (SRNL). Projected glass compositional regions that bound anticipated Defense Waste Processing Facility (DWPF) and Hanford high level waste (HLW) glass regions of interest were developed and used to generate glass compositions of interest for meeting the objectives of this study. A thorough statistical analysis was employed to allow for a wide range of waste glass compositions to be examined while minimizing the number of glasses that had to be fabricated and characterized in the laboratory. The glass compositions were divided into two sets, with 45 in the test matrix investigated by the U.S. laboratories and 30 in the test matrix investigated by KRI. Fabrication and characterization of the US and KRI-series glasses were generally handled separately. This report focuses mainly on the US-series glasses. Glasses were fabricated and characterized by SRNL and PNNL. Crystalline phases were identified by X-ray diffraction (XRD) in the quenched and canister centerline cooled (CCC) glasses and were generally iron oxides and spinels, which are not expected to impact durability of the glass. Nepheline was detected in five of the glasses after the CCC heat treatment. Chemical composition measurements for each of the glasses were conducted

  18. INTERNATIONAL STUDY OF ALUMINUM IMPACTS ON CRYSTALLIZATION IN U.S. HIGH LEVEL WASTE GLASS

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K; David Peeler, D; Tommy Edwards, T; David Best, D; Irene Reamer, I; Phyllis Workman, P; James Marra, J

    2008-09-23

    The objective of this task was to develop glass formulations for (Department of Energy) DOE waste streams with high aluminum concentrations to avoid nepheline formation while maintaining or meeting waste loading and/or waste throughput expectations as well as satisfying critical process and product performance related constraints. Liquidus temperatures and crystallization behavior were carefully characterized to support model development for higher waste loading glasses. The experimental work, characterization, and data interpretation necessary to meet these objectives were performed among three partnering laboratories: the V.G. Khlopin Radium Institute (KRI), Pacific Northwest National Laboratory (PNNL) and Savannah River National Laboratory (SRNL). Projected glass compositional regions that bound anticipated Defense Waste Processing Facility (DWPF) and Hanford high level waste (HLW) glass regions of interest were developed and used to generate glass compositions of interest for meeting the objectives of this study. A thorough statistical analysis was employed to allow for a wide range of waste glass compositions to be examined while minimizing the number of glasses that had to be fabricated and characterized in the laboratory. The glass compositions were divided into two sets, with 45 in the test matrix investigated by the U.S. laboratories and 30 in the test matrix investigated by KRI. Fabrication and characterization of the US and KRI-series glasses were generally handled separately. This report focuses mainly on the US-series glasses. Glasses were fabricated and characterized by SRNL and PNNL. Crystalline phases were identified by X-ray diffraction (XRD) in the quenched and canister centerline cooled (CCC) glasses and were generally iron oxides and spinels, which are not expected to impact durability of the glass. Nepheline was detected in five of the glasses after the CCC heat treatment. Chemical composition measurements for each of the glasses were conducted

  19. Supercontinuum generation for coherent anti- Stokes Raman scattering microscopy with photonic crystal fibers

    DEFF Research Database (Denmark)

    Pedersen, Pernille Klarskov; Isomäki, Antti; Hansen, Kim P.

    2011-01-01

    Photonic crystal fiber (PCF) designs with two zero-dispersion wavelengths (ZDWs) are experimentally investigated in order to suggest a novel PCF for coherent anti-Stokes Raman scattering (CARS) microscopy. From our investigation, we select the optimum PCF design and demonstrate a tailored spectru...

  20. Generation of polarization-entangled photon pairs in a cascade of two type-I crystals pumped by femtosecond pulses

    International Nuclear Information System (INIS)

    Nambu, Yoshihiro; Usami, Koji; Tsuda, Yoshiyuki; Matsumoto, Keiji; Nakamura, Kazuo

    2002-01-01

    We report the generation of polarization-entangled photons by femtosecond-pulse-pumped spontaneous parametric down-conversion in a cascade of two type-I crystals. Highly entangled pulsed states were obtained by introducing a temporal delay between the two orthogonal polarization components of the pump field. They exhibited high-visibility quantum interference and a large concurrence value, without the need of postselection using narrow-bandwidth spectral filters. The results are well explained by the theory which incorporates the space-time dependence of interfering two-photon amplitudes if dispersion and birefringence in the crystals are appropriately taken into account. Such a pulsed entangled photon well localized in time domain is useful for various quantum communication experiments, such as quantum cryptography and quantum teleportation

  1. On generation and evolution of seaward propagating internal solitary waves in the northwestern South China Sea

    Science.gov (United States)

    Xu, Jiexin; Chen, Zhiwu; Xie, Jieshuo; Cai, Shuqun

    2016-03-01

    In this paper, the generation and evolution of seaward propagating internal solitary waves (ISWs) detected by satellite image in the northwestern South China Sea (SCS) are investigated by a fully nonlinear, non-hydrostatic, three-dimensional Massachusetts Institute of Technology general circulation model (MITgcm). The three-dimensional (3D) modeled ISWs agree favorably with those by satellite image, indicating that the observed seaward propagating ISWs may be generated by the interaction of barotropic tidal flow with the arc-like continental slope south of Hainan Island. Though the tidal current is basically in east-west direction, different types of internal waves are generated by tidal currents flowing over the slopes with different shaped shorelines. Over the slope where the shoreline is straight, only weak internal tides are generated; over the slope where the shoreline is seaward concave, large-amplitude internal bores are generated, and since the concave isobaths of the arc-like continental slope tend to focus the baroclinic tidal energy which is conveyed to the internal bores, the internal bores can efficiently disintegrate into a train of rank-ordered ISWs during their propagation away from the slope; while over the slope where the shoreline is seaward convex, no distinct internal tides are generated. It is also implied that the internal waves over the slope are generated due to mixed lee wave mechanism. Furthermore, the effects of 3D model, continental slope curvature, stratification, rotation and tidal forcing on the generation of ISWs are discussed, respectively. It is shown that, the amplitude and phase speed of ISWs derived from a two-dimensional (2D) model are smaller than those from the 3D one, and the 3D model has an advantage over 2D one in simulating the ISWs generated by the interaction between tidal currents and 3D curved continental slope; the reduced continental slope curvature hinders the extension of ISW crestline; both weaker stratification

  2. Enhanced Cherenkov phase matching terahertz wave generation via a magnesium oxide doped lithium niobate ridged waveguide crystal

    Directory of Open Access Journals (Sweden)

    K. Takeya

    2017-01-01

    Full Text Available When combined with a nonlinear waveguide crystal, Cherenkov phase matching allows for highly effective generation of high power and broadband terahertz (THz waves. Using a ridged Lithium Niobate (LiNbO3 waveguide coupled with a specially designed silicon lens, we successfully generated THz waves with intensity of approximately three orders of magnitude stronger than those from conventional photoconductive antenna. The broadband spectrum was from 0.1 THz to 7 THz with a maximum dynamic range of 80 dB. The temporal shape of time domain pulse is a regular single cycle which could be used for high depth resolution time of flight tomography. The generated THz wave can also be easily monitored by compact room-temperature THz camera, enabling us to determine the spatial characteristics of the THz propagation.

  3. Simultaneous generation of tunable giant dispersive waves in the visible and mid-infrared regions based on photonic crystal fibers

    International Nuclear Information System (INIS)

    Zhang, Lei; Yang, Si-Gang; Chen, Hong-Wei; Chen, Ming-Hua; Xie, Shi-Zhong; Han, Ying

    2013-01-01

    Cherenkov radiation (CR) in both the visible and mid-infrared regions is simultaneously generated experimentally based on a photonic crystal fiber with two zero-dispersion wavelengths. The generation of CR in the visible region originates from solitons located in the anomalous group velocity dispersion (GVD) regime which are perturbed by positive third order dispersion. Conversely, the generation of CR in the mid-infrared region requires that the solitons in the anomalous GVD regime are perturbed by negative third order dispersion. The peak wavelength of the CR in the visible region can be tuned from 498 to 425 nm by increasing the average input pump power from 70 to 400 mW, while the peak wavelength of the CR in the mid-infrared region can be tuned from 1986 to 2279 nm by increasing the average input pump power from 70 to 320 mW. (paper)

  4. Narrowband widely tunable CW mid-infrared generator based on difference frequency generation in periodically poled KTP and KTA crystals

    Czech Academy of Sciences Publication Activity Database

    Baravets, Yauhen; Honzátko, Pavel; Todorov, Filip; Gladkov, Petar

    2016-01-01

    Roč. 48, č. 5 (2016), May ISSN 0306-8919 R&D Projects: GA MŠk LD14112 Grant - others:COST(XE) MP1204 Institutional support: RVO:67985882 Keywords : Fiber optics amplifiers * Difference-frequency generation * Mid-infrared tunable laser source Subject RIV: BH - Optics , Masers, Lasers Impact factor: 1.055, year: 2016

  5. Generation and propagation of high-order Bessel vortices in linear and non-linear crystals

    CSIR Research Space (South Africa)

    Belyi, VN

    2009-08-01

    Full Text Available E⊥ of the electric field for these beams are given by the following expressions: ( ))2exp()()( )( )exp( 20 1 10 ϕρρ iqJqJ qw zikA i zoo −+⊥ += eeE , (1) с Uniaxial crystal θs Bs2ω(ρ) Bsω(ρ) Figure 1: Geometry of SHG when wave vectors cone of Bessel... beam at fundamental )(ρωBs and second harmonic frequencies )(2 ρωBs coincides with phase-matching cone of uniaxial crystal. Proc. of SPIE Vol. 7430 74300F-2 ( ))2exp()()()cos( )( )exp( 20 1 1 ϕρργ iqJqJ qw zikA i e zee e −+⊥ −= ee...

  6. Fabrication and Characterization of Three Dimensional Photonic Crystals Generated by Multibeam Interference Lithography

    Science.gov (United States)

    2009-01-01

    Also, refractive indexes for SU8 and alumina were measured as 1.57 and 1.60, respectively. Focused Ion Beam Milling: Cross-sections of polymer and...Holographically defined polymer photonic crystals can serve as templates for subsequent deposition of high refractive index materials for applications...initiation, the polymerization reaction occurs during exposure and the interference pattern may be distorted by the resulting refractive index shifts

  7. Properties of entangled proton pairs generated in periodically poled nonlinear crystals

    Czech Academy of Sciences Publication Activity Database

    Svozilík, Jiří; Peřina ml., Jan

    2009-01-01

    Roč. 80, č. 2 (2009), 023819/1-023819/9 ISSN 1050-2947 R&D Projects: GA MŠk(CZ) OC09026; GA AV ČR IAA100100713; GA MŠk(CZ) 1M06002 Institutional research plan: CEZ:AV0Z10100522 Keywords : photon pairs * nonlinear crystals * nonlinear optics * quantum optics Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.866, year: 2009

  8. Generation of 103 fs mode-locked pulses by a gain linewidth-variable Nd,Y:CaF2 disordered crystal.

    Science.gov (United States)

    Qin, Z P; Xie, G Q; Ma, J; Ge, W Y; Yuan, P; Qian, L J; Su, L B; Jiang, D P; Ma, F K; Zhang, Q; Cao, Y X; Xu, J

    2014-04-01

    We have demonstrated a diode-pumped passively mode-locked femtosecond Nd,Y:CaF2 disordered crystal laser for the first time to our knowledge. By choosing appropriate Y-doping concentration, a broad fluorescence linewidth of 31 nm has been obtained from the gain linewidth-variable Nd,Y:CaF2 crystal. With the Nd,Y:CaF2 disordered crystal as gain medium, the mode-locked laser generated pulses with pulse duration as short as 103 fs, average output power of 89 mW, and repetition rate of 100 MHz. To our best knowledge, this is the shortest pulse generated from Nd-doped crystal lasers so far. The research results show that the Nd,Y:CaF2 disordered crystal will be a potential alternative as gain medium of repetitive chirped pulse amplification for high-peak-power lasers.

  9. Generation of X-rays by electrons recycling through thin internal targets of cyclic accelerators

    Science.gov (United States)

    Kaplin, V.; Kuznetsov, S.; Uglov, S.

    2018-05-01

    The use of thin (recycling effect) of electrons through them. The multiplicity of electron passes (M) is determined by the electron energy, accelerator parameters, the thickness, structure and material of a target and leads to an increase in the effective target thickness and the efficiency of radiation generation. The increase of M leads to the increase in the emittance of electron beams which can change the characteristics of radiation processes. The experimental results obtained using the Tomsk synchrotron and betatron showed the possibility of increasing the yield and brightness of coherent X-rays generated by the electrons passing (recycling) through thin crystals and periodic multilayers placed into the chambers of accelerators, when the recycling effect did not influence on the spectral and angular characteristics of generated X-rays.

  10. Magnetophotonic crystals based on yttrium-iron-garnet infiltrated opals: Magnetization-induced second-harmonic generation

    Science.gov (United States)

    Murzina, T. V.; Kim, E. M.; Kapra, R. V.; Moshnina, I. V.; Aktsipetrov, O. A.; Kurdyukov, D. A.; Kaplan, S. F.; Golubev, V. G.; Bader, M. A.; Marowsky, G.

    2006-01-01

    Three-dimensional magnetophotonic crystals (MPCs) based on artificial opals infiltrated by yttrium iron garnet (YIG) are fabricated and their structural, optical, and nonlinear optical properties are studied. The formation of the crystalline YIG inside the opal matrix is checked by x-ray analysis. Two templates are used for the infiltration by YIG: bare opals and those covered by a thin platinum film. Optical second-harmonic generation (SHG) technique is used to study the magnetization-induced nonlinear-optical properties of the composed MPCs. A high nonlinear magneto-optical Kerr effect in the SHG intensity is observed at the edge of the photonic band gap of the MPCs.

  11. Cascaded interactions between Raman induced solitons and dispersive waves in photonic crystal fibers at the advanced stage of supercontinuum generation.

    Science.gov (United States)

    Driben, Rodislav; Mitschke, Fedor; Zhavoronkov, Nickolai

    2010-12-06

    The complex mechanism of multiple interactions between solitary and dispersive waves at the advanced stage of supercontinuum generation in photonic crystal fiber is studied in experiment and numerical simulations. Injection of high power negatively chirped pulses near zero dispersion frequency results in an effective soliton fission process with multiple interactions between red shifted Raman solitons and dispersive waves. These interactions may result in relative acceleration of solitons with further collisions between them of quasi-elastic or quasi-plastic kinds. In the spectral domain these processes result in enhancement of certain wavelength regions within the spectrum or development of a new significant band at the long wavelength side of the spectrum.

  12. Entangled photon pair generation by spontaneous parametric down-conversion in finite-length one-dimensional photonic crystals

    International Nuclear Information System (INIS)

    Centini, M.; Sciscione, L.; Sibilia, C.; Bertolotti, M.; Perina, J. Jr.; Scalora, M.; Bloemer, M.J.

    2005-01-01

    A description of spontaneous parametric down-conversion in finite-length one-dimensional nonlinear photonic crystals is developed using semiclassical and quantum approaches. It is shown that if a suitable averaging is added to the semiclassical model, its results are in very good agreement with the quantum approach. We propose two structures made with GaN/AlN that generate both degenerate and nondegenerate entangled photon pairs. Both structures are designed so as to achieve a high efficiency of the nonlinear process

  13. Generation of weakly nonlinear nonhydrostatic internal tides over large topography: a multi-modal approach

    Directory of Open Access Journals (Sweden)

    R. Maugé

    2008-03-01

    Full Text Available A set of evolution equations is derived for the modal coefficients in a weakly nonlinear nonhydrostatic internal-tide generation problem. The equations allow for the presence of large-amplitude topography, e.g. a continental slope, which is formally assumed to have a length scale much larger than that of the internal tide. However, comparison with results from more sophisticated numerical models show that this restriction can in practice be relaxed. It is shown that a topographically induced coupling between modes occurs that is distinct from nonlinear coupling. Nonlinear effects include the generation of higher harmonics by reflection from boundaries, i.e. steeper tidal beams at frequencies that are multiples of the basic tidal frequency. With a seasonal thermocline included, the model is capable of reproducing the phenomenon of local generation of internal solitary waves by a tidal beam impinging on the seasonal thermocline.

  14. Brain mechanisms associated with internally directed attention and self-generated thought.

    Science.gov (United States)

    Benedek, Mathias; Jauk, Emanuel; Beaty, Roger E; Fink, Andreas; Koschutnig, Karl; Neubauer, Aljoscha C

    2016-03-10

    Internal cognition like imagination and prospection require sustained internally directed attention and involve self-generated thought. This fMRI study aimed to disentangle the brain mechanisms associated with attention-specific and task-specific processes during internally directed cognition. The direction of attention was manipulated by either keeping a relevant stimulus visible throughout the task, or by masking it, so that the task had to be performed "in the mind's eye". The level of self-directed thought was additionally varied between a convergent and a divergent thinking task. Internally directed attention was associated with increased activation in the right anterior inferior parietal lobe (aIPL), bilateral lingual gyrus and the cuneus, as well as with extended deactivations of superior parietal and occipital regions representing parts of the dorsal attention network. The right aIPL further showed increased connectivity with occipital regions suggesting an active top-down mechanism for shielding ongoing internal processes from potentially distracting sensory stimulation in terms of perceptual decoupling. Activation of the default network was not related to internally directed attention per se, but rather to a higher level of self-generated thought. The findings hence shed further light on the roles of inferior and superior parietal cortex for internally directed cognition.

  15. Investigation of phase matching for third-harmonic generation in silicon slow light photonic crystal waveguides using Fourier optics.

    Science.gov (United States)

    Monat, Christelle; Grillet, Christian; Corcoran, Bill; Moss, David J; Eggleton, Benjamin J; White, Thomas P; Krauss, Thomas F

    2010-03-29

    Using Fourier optics, we retrieve the wavevector dependence of the third-harmonic (green) light generated in a slow light silicon photonic crystal waveguide. We show that quasi-phase matching between the third-harmonic signal and the fundamental mode is provided in this geometry by coupling to the continuum of radiation modes above the light line. This process sustains third-harmonic generation with a relatively high efficiency and a substantial bandwidth limited only by the slow light window of the fundamental mode. The results give us insights into the physics of this nonlinear process in the presence of strong absorption and dispersion at visible wavelengths where bandstructure calculations are problematic. Since the characteristics (e.g. angular pattern) of the third-harmonic light primarily depend on the fundamental mode dispersion, they could be readily engineered.

  16. Intercellular cancer collisions generate an ejected crystal comet tail effect with fractal interface embryoid body reassembly transformation

    Directory of Open Access Journals (Sweden)

    Díaz JA

    2011-05-01

    Full Text Available Jairo A Díaz, Mauricio F Murillo, Alvaro BarreroDepartment of Pathology, Hospital Departmental Villavicencio, Hospital Departmental Granada, Medicine School, University Cooperative of Colombia, Villavicencio, Meta, ColombiaAbstract: We have documented self-assembled geometric triangular chiral crystal complexes (GTCHC and a framework of collagen vascular invariant geometric attractors in cancer tissues. This article shows how this system evolves in time. These structures are incorporated together and evolve in different ways. When the geometric core is stable, and the tissue architecture collapses, fragmented components emerge, which reveal a hidden interior identifying how each molecule is reassembled into the original mold, using one common connection, ie, a fractal self-similarity that guided the system from the beginning. GTCHC complexes generate ejected crystal comet tail effects and produce strange helicity states that arise in the form of spin domain interactions. As the crystal growth vibration stage progresses, biofractal echo images converge in a master-built construction of embryoid bodies with enolase-selective immunopositivity in relation to clusters of triangular chiral cell organization. In our electro-optic collision model, we were able to predict and replicate all the characteristics of this complex geometry that connects a physical phenomenon with the signal patterns that generate biologic chaos. Intrinsically, fractal geometry makes spatial correction errors embrace the chaotic system in a way that permits new structures to emerge, and as a result, an ordered self-assembly of embryoid bodies with neural differentiation at the final stage of cancer development is a predictable process. We hope that further investigation of these structures will lead not only to a new way of thinking about physics and biology, but also to a rewarding area in cancer research.Keywords: embryoid bodies, cancer, electro-optic collision model

  17. Cryptic iridescence in a fossil weevil generated by single diamond photonic crystals.

    Science.gov (United States)

    McNamara, Maria E; Saranathan, Vinod; Locatelli, Emma R; Noh, Heeso; Briggs, Derek E G; Orr, Patrick J; Cao, Hui

    2014-11-06

    Nature's most spectacular colours originate in integumentary tissue architectures that scatter light via nanoscale modulations of the refractive index. The most intricate biophotonic nanostructures are three-dimensional crystals with opal, single diamond or single gyroid lattices. Despite intense interest in their optical and structural properties, the evolution of such nanostructures is poorly understood, due in part to a lack of data from the fossil record. Here, we report preservation of single diamond (Fd-3m) three-dimensional photonic crystals in scales of a 735,000 year old specimen of the brown Nearctic weevil Hypera diversipunctata from Gold Run, Canada, and in extant conspecifics. The preserved red to green structural colours exhibit near-field brilliancy yet are inconspicuous from afar; they most likely had cryptic functions in substrate matching. The discovery of pristine fossil examples indicates that the fossil record is likely to yield further data on the evolution of three-dimensional photonic nanostructures and their biological functions. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  18. Substantiation of vibration strength of nuclear reactor and steam generator internals. Main problems

    International Nuclear Information System (INIS)

    Fyodorov, V.G.; Sinyavasky, V.F.

    1977-01-01

    The report details the scope and priority of studies necessary for substantiation of vibration strength of steam generator tube bundles and reactor fuel assemblies, and design modifications helping to reduce flow-induced vibration of the internals specified. Steam generator tube bundles are studied on the basis of a standard establishing vibration requirements at various stages of design, manufacture and operation of a steam generator at a nuclear power station. The main vibration characteristics of tubes obtained through model and full-scale tests are compared with calculation results. Results are provided concerning test-stand vibration tests of fuel elements and fuel assemblies. (author)

  19. On the generation and evolution of internal solitary waves in the southern Red Sea

    KAUST Repository

    Guo, Daquan; Akylas, T. R.; Zhan, Peng; Kartadikaria, Aditya R.; Hoteit, Ibrahim

    2016-01-01

    Satellite observations recently revealed trains of internal solitary waves (ISWs) in the off-shelf region between 16.0 degrees N and 16.5 degrees N in the southern Red Sea. The generation mechanism of these waves is not entirely clear, though

  20. A New Generation Fiber Optic Probe: Characterization of Biological Fluids, Protein Crystals and Ophthalmic Diseases

    Science.gov (United States)

    Ansari, Rafat R.; Suh, Kwang I.

    1996-01-01

    A new fiber optic probe developed for determining transport properties of sub-micron particles in fluids experiments in a microgravity environment has been applied to characterize particulate dispersions/suspensions in various challenging environments which have been hitherto impossible. The probe positioned in front of a sample delivers a low power light (few nW - 3mW) from a laser and guides the light which is back scattered by the suspended particles through a receiving optical fiber to a photo detector and to a digital correlator. The probe provides rapid determination of macromolecular diffusivities and their respective size distributions. It has been applied to characterize various biological fluids, protein crystals, and ophthalmic diseases.

  1. Generation of the second harmonics of Bessel light beams in a KTP crystal

    International Nuclear Information System (INIS)

    Belyi, V N; Kazak, N S; Kondratyuk, N V; Khilo, N A; Shagov, A A

    1998-01-01

    Theoretical and experimental investigations were made of the characteristic features of doubling the frequency of Bessel light beams by the oe - e interaction in a KTP crystal. All possible and scalar interactions of plane-wave components of Bessel beams were observed experimentally. The spatial structure of the second harmonic in the far zone consisted of a central spot and a concentric ring. The diffraction divergence of the central beam was weak ( ∼ 1.7 mrad). The energy conversion efficiency was ∼ 21% for a Bessel beam, which was three times higher than the efficiency of conversion of the initial laser beam. A theoretical model was based on representation of the field of the second harmonic as a superposition of Bessel beams, which provided a correct description of the observed spatial and energy characteristics of the second harmonic. (nonlinear optical phenomena and devices)

  2. Entangled, guided photon generation in (1+1)-dimensional photonic crystals

    International Nuclear Information System (INIS)

    Sciscione, L.; Centini, M.; Sibilia, C.; Bertolotti, M.; Scalora, M.

    2006-01-01

    A scheme based on photonic crystal technology is proposed as an ultrabright source of entangled photons on a miniaturized scale. The geometry consists of a multilayer microcavity, excited by a resonant pump frequency, such that the emitted photons are guided transversally to the direction of the incident pump. The entanglement occurs in direction, frequency, and polarization, and the bandwidth of the emitted photons is of the order of 1 nm. We propose a feasible design based on Al 0.3 Ga 0.7 As/Al 2 O 3 structures and predict an emission rate 10 5 pairs per second with 100 mW pump power. These results are promising for realization of chip and future quantum computer applications

  3. Computer-generated vibratory signatures for EDF PWR reactor vessel internals

    International Nuclear Information System (INIS)

    Trenty, A.; Lefevre, F.; Garreau, D.

    1992-07-01

    This paper presents a device for generation of characteristic signatures for normal or faulty vibrations on EDF PWR internal structures. The objective is to test the efficiency of methods for diagnosing faults in these structures. With this device, it is possible to build an entire PSD in several phases: choice of a general basic shape, localized addition of several kinds of background noise, generation of peaks of variable shapes, adjustment of local or global amplifications... It also offers the possibility of distorting real PSDs acquired from the reactor: shifting frequency or modifying peak shape, eliminating or adding existing shapes or shapes to be created, smoothing curves... One example is given of simulated loss of function in a hold-down spring on a computer-generated PSD of ex-core neutron noise. The device is now being used to test the potential of neural networks in recognizing faults on internal structures

  4. Dry out of a fluidized particle bed with internal heat generation

    International Nuclear Information System (INIS)

    Keowen, R.S.; Catton, I.

    1975-03-01

    An apparatus was designed to adequately simulate the characteristics of a particle bed formed by nuclear reactor fuel after the reactor has been operable for some length of time at high power. This was accomplished by using a 10 KW, 453 Kc induction heater, coupled through a multi-turn work coil to particle beds of cast steel shot and lead shot in water. The temperature response and dryout condition was determined for various bed levels, particle diameters, and heat fluxes. Analysis of the data retrieved from the bed was used to generate a family of curves to predict the necessary conditions for dryout to occur within a fluidized particle bed with internal heat generation. The results presented here, with internal heat generation, show that previous results with bottom heating and volume heating are conservative. (U.S.)

  5. Heat transfer of liquid-metal magnetohydrodynamic flow with internal heat generation

    International Nuclear Information System (INIS)

    Kumamaru, Hiroshige; Kurita, Kazuhisa; Kodama, Satoshi

    2000-01-01

    Numerical calculations on heat transfer of a magnetohydrodynamic (MHD) flow with internal heat generation in a rectangular channel have been performed for the cases of very-large Hartmann numbers, finite wall conductivities and small aspect ratio (i.e. small length ratios of the channel side perpendicular to the applied magnetic field and the side parallel to the field), simulating typical conditions for a fusion-reactor blanket. The Nusselt numbers of the MHD flow in rectangular channels with aspect ratios of 1/10 to 1/40 for Hartmann numbers of ∼5 x 10 5 become ∼10 times higher than those for the corresponding flow under no magnetic field. The Nusselt number becomes higher as the internal heat generation rate increases as far as the heat generation rates in a fusion reactor blanket are considered. (author)

  6. Generating Efficient Femtosecond Mid-infrared Pulse by Single Near-infrared Pump Wavelength in Bulk Nonlinear Crystal Without Phase-matching

    DEFF Research Database (Denmark)

    Zhou, Binbin; Guo, Hairun; Bache, Morten

    2014-01-01

    We experimentally demonstrate efficient mid-infrared pulse generation by dispersive wave radiation in bulk lithium niobate crystal. Femtosecond mid-IR pulses centering from 2.8-2.92 μm are generated using the single pump wavelengths from 1.25-1.45 μm. © 2014 Optical Society of America...

  7. Experimental generation of discrete ultraviolet wavelength by cascaded intermodal four-wave mixing in a multimode photonic crystal fiber.

    Science.gov (United States)

    Yuan, Jinhui; Kang, Zhe; Li, Feng; Zhang, Xianting; Mei, Chao; Zhou, Guiyao; Sang, Xinzhu; Wu, Qiang; Yan, Binbin; Zhou, Xian; Zhong, Kangping; Wang, Kuiru; Yu, Chongxiu; Farrell, Gerald; Lu, Chao; Tam, Hwa Yaw; Wai, P K A

    2017-09-15

    In this Letter, we demonstrate experimentally for the first time, to the best of our knowledge, discrete ultraviolet (UV) wavelength generation by cascaded intermodal FWM when femtosecond pump pulses at 800 nm are launched into the deeply normal dispersion region of the fundamental guided mode of a multimode photonic crystal fiber (MPCF). For pump pulses at average input powers of P av =450, 550, and 650 mW, the first anti-Stokes waves are generated at the visible wavelength of 538.1 nm through intermodal phase matching between the fundamental and second-order guided mode of the MPCF. The first anti-Stokes waves generated then serve as the secondary pump for the next intermodal FWM process. The second anti-Stokes waves in the form of the third-order guided mode are generated at the UV wavelength of 375.8 nm. The maximum output power is above 10 mW for P av =650  mW. We also confirm that the influences of fiber bending and intermodal walk-offs on the cascaded intermodal FWM-based frequency conversion process are negligible.

  8. Protecting the environment for future generations. Principles and actors in international environmental law

    Energy Technology Data Exchange (ETDEWEB)

    Proelss, Alexander (ed.) [Trier Univ. (Germany). Inst. of Environmental and Technology Law

    2017-08-01

    This book compiles the written versions of presentations held at the occasion of an international symposium entitled ''Protecting the Environment for Future Generations - Principles and Actors in International Environmental Law''. The symposium was organized by the Institute of Environmental and Technology Law of Trier University (IUTR) on the basis of a cooperation scheme with the Environmental Law Institute of the Johannes Kepler University Linz, Austria, and took place in Trier on 29-30 October 2015. It brought together a distinguished group of experts from Europe and abroad to address current issues of international and European environmental law. The main objective of the symposium was to take stock of the actors and principles of international and European environmental law, and to analyze how and to what extent these principles have been implemented on the supranational and domestic legal levels.

  9. Surface role in reorientation of internal layers of molybdenum single crystal during rolling

    International Nuclear Information System (INIS)

    Antsiforov, P.N.; Gorordetskij, S.D.; Markashova, A.I.; Martynenko, S.I.

    1991-01-01

    Structure, orientations and chemical composition of surface and internal layers of molybdenum rolled monocrystals are studied using electron microscopy, X-ray and Auger-analyses. Model of reorientation allowing to determine relation of deformation mechanism localized in surface layer with reorientation of internal layers, is described to explain the results

  10. Difference-frequency generation in the field of a few-cycle laser pulse propagating in a GaAs crystal with a domain structure

    International Nuclear Information System (INIS)

    Oganesyan, David L; Vardanyan, Aleksandr O; Oganesyan, G D

    2013-01-01

    Difference-frequency generation in a GaAs crystal with a periodic domain structure in the field of a few-cycle laser pulse is considered for the case of weakly pronounced material dispersion. The straight-line method is used to solve numerically the system of coupled nonlinear partial differential equations describing the evolution of the electric field of this laser pulse in GaAs crystals with periodic and chirped domain structures. It is shown that application of a GaAs crystal with a chirped domain structure makes it possible to control the frequency-modulation law for a broadband differencefrequency pulse. (nonlinear optical phenomena)

  11. Monolayer-crystal streptavidin support films provide an internal standard of cryo-EM image quality

    Energy Technology Data Exchange (ETDEWEB)

    Han, Bong-Gyoon [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Watson, Zoe [Univ. of California, Berkeley, CA (United States); Cate, Jamie H. D. [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Glaeser, Robert M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-03-01

    Analysis of images of biotinylated Escherichia coli 70S ribosome particles, bound to streptavidin affinity grids, demonstrates that the image-quality of particles can be predicted by the image-quality of the monolayer crystalline support film. Also, the quality of the Thon rings is a good predictor of the image-quality of particles, but only when images of the streptavidin crystals extend to relatively high resolution. When the estimated resolution of streptavidin was 5 Å or worse, for example, the ribosomal density map obtained from 22,697 particles went to only 9.5 Å, while the resolution of the map reached 4.0 Å for the same number of particles, when the estimated resolution of streptavidin crystal was 4 Å or better. It thus is easy to tell which images in a data set ought to be retained for further work, based on the highest resolution seen for Bragg peaks in the computed Fourier transforms of the streptavidin component. The refined density map obtained from 57,826 particles obtained in this way extended to 3.6 Å, a marked improvement over the value of 3.9 Å obtained previously from a subset of 52,433 particles obtained from the same initial data set of 101,213 particles after 3-D classification. These results are consistent with the hypothesis that interaction with the air-water interface can damage particles when the sample becomes too thin. Finally, streptavidin monolayer crystals appear to provide a good indication of when that is the case.

  12. Third harmonic generation of CO2 laser radiation in AgGaSe2 crystal

    Indian Academy of Sciences (India)

    journal of. September 2000 physics pp. 405–412. Third harmonic generation of .... cell, the short pulse is accompanied by an unavoidable background pulse of 216 ns dura- ... the long pulse laser interacts with only a small number of SF molecules. ... illuminates the discharge region and produces electrons by ionization of ...

  13. Socio-economic impacts of nuclear generating stations: Crystal River Unit 3 case study

    International Nuclear Information System (INIS)

    Bergmann, P.A.

    1982-07-01

    This report documents a case study of the socio-economic impacts of the construction and operation of the Crystal River Unit 3 nuclear power station. It is part of a major post-licensing study of the socio-economic impacts at twelve nuclear power stations. The case study covers the period beginning with the announcement of plans to construct the reactor and ending in the period 1980 to 1981. The case study deals with changes in the economy, population, settlement patterns and housing, local government and public services, social structure, and public response in the study area during the construction/operation of the reactor. A regional modeling approach is used to trace the impact of construction/operation on the local economy, labor market, and housing market. Emphasis in the study is on the attribution of socio-economic impacts to the reactor or other causal factors. As part of the study of local public response to the construction/operation of the reactor, the effects of the Three Mile Island accident are examined

  14. Internally Generated Conscious Contents: Interactions between Sustained Mental Imagery and Involuntary Subvocalizations

    Directory of Open Access Journals (Sweden)

    Hyein eCho

    2014-12-01

    Full Text Available The conscious field includes not only representations about external stimuli (e.g., percepts, but also conscious contents associated with internal states, such as action-related intentions (e.g., urges. Although understudied, the latter may provide unique insights into the nature of consciousness. To illuminate these phenomena, in a new experimental paradigm (Reflexive Imagery Task [RIT], participants were instructed to not subvocalize the names of visually-presented objects. Each object was presented for 10 s on a screen. Participants indicated whenever they involuntarily subvocalized the object name. Research has revealed that it is difficult to suppress such subvocalizations, which occur on over 80% of the trials. Can the effect survive if one intentionally generates a competing (internally-generated conscious content? If so, this would suggest that intentional and unintentional contents can co-exist simultaneously in consciousness in interesting ways. To investigate this possibility, in one condition, participants were instructed to reiteratively subvocalize a speech sound (da, da, da throughout the trial. This internally generated content is self-generated and intentional. Involuntary subvocalizations of object names still arose on over 80% of the trials. One could hypothesize that subvocalizations occurred because of the pauses between the intended speech sounds, but this is inconsistent with the observation that comparable results arose even when participants subvocalized a continuous, unbroken hum (daaa…. throughout the trial. Regarding inter-content interactions, the continuous hum and object name seem to co-exist simultaneously in consciousness. This intriguing datum requires further investigation. We discuss the implications of this new paradigm for the study of internally-generated conscious contents.

  15. Internal transmission coefficient in charges carrier generation layer of graphene/Si based solar cell device

    International Nuclear Information System (INIS)

    Rosikhin, Ahmad; Winata, Toto

    2016-01-01

    Internal transmission profile in charges carrier generation layer of graphene/Si based solar cell has been explored theoretically. Photovoltaic device was constructed from graphene/Si heterojunction forming a multilayer stuck with Si as generation layer. The graphene/Si sheet was layered on ITO/glass wafer then coated by Al forming Ohmic contact with Si. Photon incident propagate from glass substrate to metal electrode and assumed that there is no transmission in Al layer. The wavelength range spectra used in this calculation was 200 – 1000 nm. It found that transmission intensity in the generation layer show non-linear behavior and partitioned by few areas which related with excitation process. According to this information, it may to optimize the photons absorption to create more excitation process by inserting appropriate material to enhance optical properties in certain wavelength spectra because of the exciton generation is strongly influenced by photon absorption.

  16. Proceedings of the third international steam generator and heat exchanger conference

    International Nuclear Information System (INIS)

    1998-01-01

    The Third International Steam Generator and Heat Exchanger conference had the objective to present the state of knowledge of steam generator performance and life management, and also heat exchanger technology. As this conference followed on from the previous conferences held in Toronto in 1990 and 1994, the emphasis was on recent developments, particularly those of the last 4 years. The conference provided an opportunity to operators, designers and researchers in the field of steam generation associated with electricity generation by nuclear energy to present their findings and exchange ideas. The conference endeavoured to do this over the widest possible range of subject areas, including: general operating experience, life management and fitness for service strategies, maintenance and inspection, thermalhydraulics, vibration, fretting and fatigue, materials, chemistry and corrosion and the regulatory issues

  17. Proceedings of the third international steam generator and heat exchanger conference

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-07-01

    The Third International Steam Generator and Heat Exchanger conference had the objective to present the state of knowledge of steam generator performance and life management, and also heat exchanger technology. As this conference followed on from the previous conferences held in Toronto in 1990 and 1994, the emphasis was on recent developments, particularly those of the last 4 years. The conference provided an opportunity to operators, designers and researchers in the field of steam generation associated with electricity generation by nuclear energy to present their findings and exchange ideas. The conference endeavoured to do this over the widest possible range of subject areas,including: general operating experience, life management and fitness for service strategies, maintenance and inspection, thermalhydraulics, vibration, fretting and fatigue, materials, chemistry and corrosion and the regulatory issues.

  18. Internal stress distribution for generating closure domains in laser-irradiated Fe–3%Si(110) steels

    International Nuclear Information System (INIS)

    Iwata, Keiji; Imafuku, Muneyuki; Orihara, Hideto; Sakai, Yusuke; Ohya, Shin-Ichi; Suzuki, Tamaki; Shobu, Takahisa; Akita, Koichi; Ishiyama, Kazushi

    2015-01-01

    Internal stress distribution for generating closure domains occurring in laser-irradiated Fe–3%Si(110) steels was investigated using high-energy X-ray analysis and domain theory based on the variational principle. The measured triaxial stresses inside the specimen were compressive and the stress in the rolling direction became more dominant than stresses in the other directions. The calculations based on the variational principle of magnetic energy for closure domains showed that the measured triaxial stresses made the closure domains more stable than the basic domain without closure domains. The experimental and calculation results reveal that the laser-introduced internal stresses result in the occurrence of the closure domains

  19. Myotonic Dystrophy Type 1 RNA Crystal Structures Reveal Heterogeneous 1 × 1 Nucleotide UU Internal Loop Conformations

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Amit; Park, HaJeung; Fang, Pengfei; Parkesh, Raman; Guo, Min; Nettles, Kendall W.; Disney, Matthew D. (Scripps)

    2012-03-27

    RNA internal loops often display a variety of conformations in solution. Herein, we visualize conformational heterogeneity in the context of the 5'CUG/3'GUC repeat motif present in the RNA that causes myotonic dystrophy type 1 (DM1). Specifically, two crystal structures of a model DM1 triplet repeating construct, 5'r[{und UU}GGGC(C{und U}G){sub 3}GUCC]{sub 2}, refined to 2.20 and 1.52 {angstrom} resolution are disclosed. Here, differences in the orientation of the 5' dangling UU end between the two structures induce changes in the backbone groove width, which reveals that noncanonical 1 x 1 nucleotide UU internal loops can display an ensemble of pairing conformations. In the 2.20 {angstrom} structure, CUGa, the 5' UU forms a one hydrogen-bonded pair with a 5' UU of a neighboring helix in the unit cell to form a pseudoinfinite helix. The central 1 x 1 nucleotide UU internal loop has no hydrogen bonds, while the terminal 1 x 1 nucleotide UU internal loops each form a one-hydrogen bond pair. In the 1.52 {angstrom} structure, CUGb, the 5' UU dangling end is tucked into the major groove of the duplex. While the canonically paired bases show no change in base pairing, in CUGb the terminal 1 x 1 nucleotide UU internal loops now form two hydrogen-bonded pairs. Thus, the shift in the major groove induced by the 5' UU dangling end alters noncanonical base patterns. Collectively, these structures indicate that 1 x 1 nucleotide UU internal loops in DM1 may sample multiple conformations in vivo. This observation has implications for the recognition of this RNA, and other repeating transcripts, by protein and small molecule ligands.

  20. Stable, high power, high efficiency picosecond ultraviolet generation at 355 nm in K3B6O10 Br crystal

    Science.gov (United States)

    Hou, Z. Y.; Wang, L. R.; Xia, M. J.; Yan, D. X.; Zhang, Q. L.; Zhang, L.; Liu, L. J.; Xu, D. G.; Zhang, D. X.; Wang, X. Y.; Li, R. K.; Chen, C. T.

    2018-06-01

    We demonstrate a high efficiency and high power picosecond ultraviolet source at 355 nm with stable output by sum frequency generation from a Nd:YAG laser using a type-I critically phase matched K3B6O10 Br crystal as nonlinear optical material. Conversion efficiency as high as 30.8% was achieved using a 25 ps laser at 1064 nm operated at 10 Hz. Similar work is done by using a 35 W 10 ps laser at 1064 nm as the pump source with a repetition rate of 80 MHz, and the highest average output power obtained was up to 5.3 W. In addition, the power stability of the 355 nm output power measurement shows that the standard deviation fluctuations of the average power are ±0.69% and ±0.91% at 3.0 W and 3.5 W, respectively.

  1. Effect of Hot-isostatic Pressing on Microstructure and Mechanical Properties of Second Generation Single Crystal Superalloy DD6

    Directory of Open Access Journals (Sweden)

    GUO Hui-ming

    2016-10-01

    Full Text Available Effects of the hot-isostatic pressing (HIP temperature (1280,1300,1320℃ on microstructures and mechanical properties of a second generation single crystal superalloy DD6 were investigated. The results show that the HIP treatment significantly decrease the cast porosity number of DD6 compared with standard treated specimens. Especially, the cast porosity volume fraction is deceased from 0.31% to 0.04% after the HIP treatment of 1300℃/100MPa, 4h. The cast eutectic volume fractions are remarkably reduced with increasing HIP temperature. The HIP treatments nearly unchanged the creep lives, While they greatly promote the low cycle fatigue lives. The elimination of cast microspores using the HIP treatment of 1300℃/100MPa, 4h result in the inhibition of crack initiation during fatigue and improve the low cycle fatigue lives one order of magnitude larger than that after standard heat treatment.

  2. Tricyanomethane and Its Ketenimine Tautomer: Generation from Different Precursors and Analysis in Solution, Argon Matrix, and as a Single Crystal.

    Science.gov (United States)

    Banert, Klaus; Chityala, Madhu; Hagedorn, Manfred; Beckers, Helmut; Stüker, Tony; Riedel, Sebastian; Rüffer, Tobias; Lang, Heinrich

    2017-08-01

    Solutions of azidomethylidenemalononitrile were photolyzed at low temperatures to produce the corresponding 2H-azirine and tricyanomethane, which were analyzed by low-temperature NMR spectroscopy. The latter product was also observed after short thermolysis of the azide precursor in solution whereas irradiation of the azide isolated in an argon matrix did not lead to tricyanomethane, but to unequivocal detection of the tautomeric ketenimine by IR spectroscopy for the first time. When the long-known "aquoethereal" greenish phase generated from potassium tricyanomethanide, dilute sulfuric acid, and diethyl ether was rapidly evaporated and sublimed, a mixture of hydronium tricyanomethanide and tricyanomethane was formed instead of the previously claimed ketenimine tautomer. Under special conditions of sublimation, single crystals of tricyanomethane could be isolated, which enabled the analysis of the molecular structure by X-ray diffraction. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Real-time optical correlator using computer-generated holographic filter on a liquid crystal light valve

    Science.gov (United States)

    Chao, Tien-Hsin; Yu, Jeffrey

    1990-01-01

    Limitations associated with the binary phase-only filter often used in optical correlators are presently circumvented in the writing of complex-valued data on a gray-scale spatial light modulator through the use of a computer-generated hologram (CGH) algorithm. The CGH encodes complex-valued data into nonnegative real CGH data in such a way that it may be encoded in any of the available gray-scale spatial light modulators. A CdS liquid-crystal light valve is used for the complex-valued CGH encoding; computer simulations and experimental results are compared, and the use of such a CGH filter as the synapse hologram in a holographic optical neural net is discussed.

  4. Accelerated rogue waves generated by soliton fusion at the advanced stage of supercontinuum formation in photonic-crystal fibers.

    Science.gov (United States)

    Driben, Rodislav; Babushkin, Ihar

    2012-12-15

    Soliton fusion is a fascinating and delicate phenomenon that manifests itself in optical fibers in case of interaction between copropagating solitons with small temporal and wavelength separation. We show that the mechanism of acceleration of a trailing soliton by dispersive waves radiated from the preceding one provides necessary conditions for soliton fusion at the advanced stage of supercontinuum generation in photonic-crystal fibers. As a result of fusion, large-intensity robust light structures arise and propagate over significant distances. In the presence of small random noise the delicate condition for the effective fusion between solitons can easily be broken, making the fusion-induced giant waves a rare statistical event. Thus oblong-shaped giant accelerated waves become excellent candidates for optical rogue waves.

  5. Generation of arbitrary vector beams with liquid crystal polarization converters and vector-photoaligned q-plates

    International Nuclear Information System (INIS)

    Chen, Peng; Ji, Wei; Wei, Bing-Yan; Hu, Wei; Lu, Yan-Qing; Chigrinov, Vladimir

    2015-01-01

    Arbitrary vector beams (VBs) are realized by the designed polarization converters and corresponding vector-photoaligned q-plates. The polarization converter is a specific twisted nematic cell with one substrate homogeneously aligned and the other space-variantly aligned. By combining a polarization-sensitive alignment agent with a dynamic micro-lithography system, various categories of liquid crystal polarization converters are demonstrated. Besides, traditional radially/azimuthally polarized light, high-order and multi-ringed VBs, and a VB array with different orders are generated. The obtained converters are further utilized as polarization masks to implement vector-photoaligning. The technique facilitates both the volume duplication of these converters and the generation of another promising optical element, the q-plate, which is suitable for the generation of VBs for coherent lasers. The combination of proposed polarization converters and correspondingly fabricated q-plates would drastically enhance the capability of polarization control and may bring more possibilities for the design of photonic devices

  6. Supercontinuum generation in optimized photonic crystal fiber at 1.3 μm for optical coherence tomography

    Directory of Open Access Journals (Sweden)

    Ferhat M. L.

    2016-01-01

    Full Text Available In this paper, we have designed a high nonlinear photonic crystal fiber (HN-PCF based on square-lattice geometry with the zero dispersion wavelength (ZDW around 1300 nm. The exploitation of different nonlinear mechanisms in the pulse propagation allows supercontinuum generation, which is used to enhance the axial resolution of the optical coherence tomography (OCT systems. First mechanism demonstrated is the soliton self-compression, we came up to realize pulse compression of 28.4 fs around 1300 nm by the generation of solitons of different orders to obtain ultrashort pulses of about 4 fs pulses in a PCF length of 66cm, then, we improved the pulse compression until 1.2 fs in a PCF length of 26 cm.The exploitation of the interplay between many nonlinear effects as self-phase modulation, intrapulse Raman scattering and self-steepening as second mechanism allows a generation of supercontinuum with a spectral bandwith of SBW=260 nm. The obtained spectral bandwidth could contribute to enhance the OCwith OCT imaging axial resolution which can be evaluated to 2.8 μm in air, working at 1.3 μm center wavelength which is widely used in several fields.

  7. Spectrally-isolated violet to blue wavelength generation by cascaded degenerate four-wave mixing in a photonic crystal fiber.

    Science.gov (United States)

    Yuan, Jinhui; Kang, Zhe; Li, Feng; Zhang, Xianting; Zhou, Guiyao; Sang, Xinzhu; Wu, Qiang; Yan, Binbin; Zhou, Xian; Wang, Liang; Zhong, Kangping; Wang, Kuiru; Yu, Chongxiu; Tam, Hwa Yaw; Wai, P K A

    2016-06-01

    Generation of spectrally-isolated wavelengths in the violet to blue region based on cascaded degenerate four-wave mixing (FWM) is experimentally demonstrated for the first time in a tailor-made photonic crystal fiber, which has two adjacent zero dispersion wavelengths (ZDWs) at 696 and 852 nm in the fundamental mode. The influences of the wavelength λp and the input average power Pav of the femtosecond pump pulses on the phase-matched frequency conversion process are studied. When femtosecond pump pulses at λp of 880, 870, and 860 nm and Pav of 500 mW are coupled into the normal dispersion region close to the second ZDW, the first anti-Stokes waves generated near the first ZDW act as a secondary pump for the next FWM process. The conversion efficiency ηas2 of the second anti-Stokes waves, which are generated at the violet to blue wavelengths of 430, 456, and 472 nm, are 4.8, 6.48, and 9.66%, for λp equalling 880, 870, and 860 nm, respectively.

  8. Generational Differences in Internalized Transnegativity and Psychological Distress Among Feminine Spectrum Transgender People.

    Science.gov (United States)

    Jackman, Kasey B; Dolezal, Curtis; Bockting, Walter O

    2018-01-01

    This study examined internalized transnegativity and psychological distress in two age groups of transgender individuals who identified their gender identity on the feminine spectrum (rather than congruent with their male sex assigned at birth). Due to greater visibility and acceptance of gender diversity in the United States, we hypothesized that internalized transnegativity would be lower in the younger compared with the older group, and that the younger generation would, therefore, report lower levels of psychological distress than the older generation. The study sample consisted of trans-feminine individuals (N = 440) who completed a online survey of the U.S. transgender population and comprised a younger group aged 18-24 years (n = 133) and an older group aged 40 years and older (n = 307). Internalized transnegativity was assessed using the Transgender Identity Survey, and psychological distress was assessed with the Brief Symptom Inventory 18. We used regression and mediation analysis to examine differences between the two groups. Contrary to our expectations, the older group reported significantly lower levels of both internalized transnegativity and psychological distress compared with the younger group. Internalized transnegativity partially mediated the relationship between age group and psychological distress. Despite greater visibility of transgender people and increasing acceptance of gender diversity in the United States, the younger trans-feminine individuals reported more psychological distress than the older transfeminine individuals, which was, in part, related to internalized transnegativity. Trans-feminine individuals may benefit from culturally sensitive and clinically competent mental health services to alleviate internalized transnegativity and psychological distress.

  9. Internal stresses in steel plate generated by shape memory alloy inserts

    International Nuclear Information System (INIS)

    Malard, B.; Pilch, J.; Sittner, P.; Davydov, V.; Sedlák, P.; Konstantinidis, K.; Hughes, D.J.

    2012-01-01

    Graphical abstract: Display Omitted Highlights: ► Thermoresponsive internal stresses introduced into steel by embedding SMA inclusions. ► Neutron strain scanning on steel plate coupons with NiTi inserts at 21 °C and 130 °C. ► Internal stress field in steel evaluated directly from strains and by FE simulation. ► Internal stress generation by SMA insert resistant to thermal and mechanical fatigue. - Abstract: Neutron strain scanning was employed to investigate the internal stress fields in steel plate coupons with embedded prestrained superelastic NiTi shape memory alloy inserts. Strain fields in steel were evaluated at T = 21 °C and 130 °C on virgin coupons as well as on mechanically and thermally fatigued coupons. Internal stress fields were evaluated by direct calculation of principal stress components from the experimentally measured lattice strains as well as by employing an inverse finite element modeling approach. It is shown that if the NiTi inserts are embedded into the elastic steel matrix following a carefully designed technological procedure, the internal stress fields vary with temperature in a reproducible and predictable way. It is estimated that this mechanism of internal stress generation can be safely applied in the temperature range from −20 °C to 150 °C and is relatively resistant to thermal and mechanical fatigue. The predictability and fatigue endurance of the mechanism are of essential importance for the development of future smart metal matrix composites or smart structures with embedded shape memory alloy components.

  10. Exact and near backscattering measurements of the linear depolarisation ratio of various ice crystal habits generated in a laboratory cloud chamber

    International Nuclear Information System (INIS)

    Smith, Helen R.; Connolly, Paul J.; Webb, Ann R.; Baran, Anthony J.

    2016-01-01

    Ice clouds were generated in the Manchester Ice Cloud Chamber (MICC), and the backscattering linear depolarisation ratio, δ, was measured for a variety of habits. To create an assortment of particle morphologies, the humidity in the chamber was varied throughout each experiment, resulting in a range of habits from the pristine to the complex. This technique was repeated at three temperatures: −7 °C, −15 °C and −30 °C, in order to produce both solid and hollow columns, plates, sectored plates and dendrites. A linearly polarised 532 nm continuous wave diode laser was directed through a section of the cloud using a non-polarising 50:50 beam splitter. Measurements of the scattered light were taken at 178°, 179° and 180°, using a Glan–Taylor prism to separate the co- and cross-polarised components. The intensities of these components were measured using two amplified photodetectors and the ratio of the cross- to co-polarised intensities was measured to find the linear depolarisation ratio. In general, it was found that Ray Tracing over-predicts the linear depolarisation ratio. However, by creating more accurate particle models which better represent the internal structure of ice particles, discrepancies between measured and modelled results (based on Ray Tracing) were reduced. - Highlights: • Linear depolarisation ratio was measured for various crystal habits. • Measurements were taken at 178°, 179° and 180°. • Various crystal properties were modelled and tested in ray tracing. • Measured and modelled results are discussed. • Modelled results are generally found to overpredict LDR.

  11. Multi-octave supercontinuum generation from mid-infrared filamentation in a bulk crystal

    Directory of Open Access Journals (Sweden)

    Faccio D.

    2013-03-01

    Full Text Available We present supercontinuum generation pumped by femtosecond mid-infrared pulses in a bulk homogeneous material. The spectrum extends from 450 nm into the midinfrared, and carries high spectral energy density (3 pJ/nm–10 nJ/nm. The supercontinuum has high shot-to-shot reproducibility and preserves the carrier-to-envelope phase. Our result paves the way for compact supercontinuum sources with unprecedented bandwidth.

  12. Sum-frequency nonlinear Cherenkov radiation generated on the boundary of bulk medium crystal.

    Science.gov (United States)

    Wang, Xiaojing; Cao, Jianjun; Zhao, Xiaohui; Zheng, Yuanlin; Ren, Huaijin; Deng, Xuewei; Chen, Xianfeng

    2015-12-14

    We demonstrated experimentally a method to generate the sum-frequency Nonlinear Cherenkov radiation (NCR) on the boundary of bulk medium by using two synchronized laser beam with wavelength of 1300 nm and 800 nm. It is also an evidence that the polarization wave is always confined to the boundary. Critical conditions of surface sum-frequency NCR under normal and anomalous dispersion condition is discussed.

  13. Self-organizing hybrid Cartesian grid generation and application to external and internal flow problems

    Energy Technology Data Exchange (ETDEWEB)

    Deister, F.; Hirschel, E.H. [Univ. Stuttgart, IAG, Stuttgart (Germany); Waymel, F.; Monnoyer, F. [Univ. de Valenciennes, LME, Valenciennes (France)

    2003-07-01

    An automatic adaptive hybrid Cartesian grid generation and simulation system is presented together with applications. The primary computational grid is an octree Cartesian grid. A quasi-prismatic grid may be added for resolving the boundary layer region of viscous flow around the solid body. For external flow simulations the flow solver TAU from the ''deutsche zentrum fuer luft- und raumfahrt (DLR)'' is integrated in the simulation system. Coarse grids are generated automatically, which are required by the multilevel method. As an application to an internal problem the thermal and dynamic modeling of a subway station is presented. (orig.)

  14. New generation of one-dimensional photonic crystal cavities as robust high-efficient frequency converter

    Science.gov (United States)

    Parvini, T. S.; Tehranchi, M. M.; Hamidi, S. M.

    2017-07-01

    An effective method is proposed to design finite one-dimensional photonic crystal cavities (PhCCs) as robust high-efficient frequency converter. For this purpose, we consider two groups of PhCCs which are constructed by stacking m nonlinear (LiNbO3) and n linear (air) layers with variable thicknesses. In the first group, the number of linear layers is less than the nonlinear layers by one and in the second group by two. The conversion efficiency is calculated as a function of the arrangement and thicknesses of the linear and nonlinear layers by benefiting from nonlinear transfer matrix method. Our numerical simulations show that for each group of PhCCs, there is a structural formula by which the configurations with the highest efficiency can be constructed for any values of m and n (i.e. any number of layers). The efficient configurations are equivalent to Fabry-Pérot cavities that depend on the relationship between m and n and the mirrors in two sides of these cavities can be periodic or nonperiodic. The conversion efficiencies of these designed PhCCs are more than 5 orders of magnitude higher than the perfect ones which satisfy photonic bandgap edge and quasi-phase matching. Moreover, the results reveal that conversion efficiencies of Fabry-Pérot cavities with non-periodic mirrors are one order of magnitude higher than those with periodic mirrors. The major physical mechanisms of the enhancement are quasi-phase matching effect, cavity effect induced by dispersive mirrors, and double resonance for the pump and the harmonic fields in defect state. We believe that this method is very beneficial to the design of high-efficient compact optical frequency converters.

  15. The internal flow pattern analysis of a tidal power turbine operating on bidirectional generation-pumping

    International Nuclear Information System (INIS)

    Luo, Y Y; Xiao, Y X; Wang, Z W

    2013-01-01

    Using tidal energy can reduce environment pollution, save conventional energy and improve energy structure, hence it presents great advantage and is developing potential. Influenced by flood tide and low tide, a fully functional tidal power station needs to experience six operating modes, including bidirectional generation, pumping and sluice; the internal unsteady flow pattern and dynamic characters are very complicated. Based on a bidirectional tidal generator unit, three-dimensional unsteady flows in the flow path were calculated for four typical operating conditions with the pressure pulsation characteristics analyzed. According to the numerical results, the internal flow characteristics in the flow path were discussed. The influence of gravity to the hydraulic performance and flow characteristics were analysed. The results provide a theoretical analysis method of the hydraulic optimization design of the same type unit as well as a direction for stable operation and optimal scheduling of existing tidal power unit

  16. Conflict between internal combustion engine and thermoelectric generator during waste heat recovery in cars

    Science.gov (United States)

    Korzhuev, M. A.

    2011-02-01

    It is shown that an internal combustion engine and a thermoelectric generator (TEG) arranged on the exhaust pipe of this engine come into the conflict of thermal machines that is related to using the same energy resource. The conflict grows with increasing useful electric power W e of the TEG, which leads to the limitation of both the maximum TEG output power ( W {e/max}) and the possibility of waste heat recovery in cars.

  17. On the generation and evolution of internal solitary waves in the southern Red Sea

    KAUST Repository

    Guo, Daquan

    2016-11-28

    Satellite observations recently revealed trains of internal solitary waves (ISWs) in the off-shelf region between 16.0 degrees N and 16.5 degrees N in the southern Red Sea. The generation mechanism of these waves is not entirely clear, though, as the observed generation sites are far away (50 km) from the shelf break and tidal currents are considered relatively weak in the Red Sea. Upon closer examination of the tide properties in the Red Sea and the unique geometry of the basin, it is argued that the steep bathymetry and a relatively strong tidal current in the southern Red Sea provide favorable conditions for the generation of ISWs. To test this hypothesis and further explore the evolution of ISWs in the basin, 2-D numerical simulations with the nonhydrostatic MIT general circulation model (MITgcm) were conducted. The results are consistent with the satellite observations in regard to the generation sites, peak amplitudes and the speeds of first-mode ISWs. Moreover, our simulations suggest that the generation process of ISWs in the southern Red Sea is similar to the tide-topography interaction mechanism seen in the South China Sea. Specifically, instead of ISWs arising in the immediate vicinity of the shelf break via a hydraulic lee wave mechanism, a broad, energetic internal tide is first generated, which subsequently travels away from the shelf break and eventually breaks down into ISWs. Sensitivity runs suggest that ISW generation may also be possible under summer stratification conditions, characterized by an intermediate water intrusion from the strait of Bab el Mandeb.

  18. Electric-field-induced internal deformation in piezoelectric BiB{sub 3}O{sub 6} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, O.; Gorfman, S.; Pietsch, U. [Solid State Physics Department, University of Siegen (Germany)

    2008-11-15

    For the first time electric-field-induced atomic displacements (internal strains) in non-ferroelectric polar BiB{sub 3}O{sub 6} single crystal plates (point symmetry 2) were investigated using X-ray diffraction technique. The intensity variations of selected Bragg reflections were collected for three different orientations of the applied external electric field vector with respect to the crystal lattice and used for calculating the microscopic structural response of BiB{sub 3}O{sub 6}. Due to the limited number of the reflections providing measurable changes in Bragg intensities we restricted ourselves in analyzing the shift of the B{sub 3}O{sub 6} sublattice relative to the Bi one. In addition, we considered the deformation of the Bi-O, B(1)-O and B(2)-O bond lengths and identified the [B(2)O{sub 3}] group as the most sensitive structural unit to an external electric perturbation. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. 7.5 W blue light generation at 452 nm by internal frequency doubling of a continuous-wave Nd-doped fiber laser.

    Science.gov (United States)

    Leconte, Baptiste; Gilles, Hervé; Robin, Thierry; Cadier, Benoit; Laroche, Mathieu

    2018-04-16

    We present the first frequency-doubled neodymium-doped fiber laser generating multi-watt CW power near 450 nm. A bow-tie resonator incorporating a LBO nonlinear crystal is integrated within a Nd-doped fiber laser emitting near 900 nm. This scheme achieves an IR to blue conversion efficiency close to 55% without any active control of the internal resonant cavity. As a result, up to 7.5 W of linearly-polarized blue power is generated, with beam quality factors M x 2 ~1.0 and M y 2 ~1.5. A simple numerical model has been developed to optimize and analyse the IR to blue conversion efficiency in the resonant cavity. Performance limitations and prospects for further improvements are discussed.

  20. Electron spin echo studies of the internal motion of radicals in crystals: Phase memory vs correlation time

    International Nuclear Information System (INIS)

    Kispert, L.D.; Bowman, M.K.; Norris, J.R.; Brown, M.S.

    1982-01-01

    An electron spin echo (ESE) study of the internal motion of the CH 2 protons in irradiated zinc acetate dihydrate crystals shows that quantitative measurements of the motional correlation time can be obtained quite directly from pulsed measurements. In the slow motional limit, the motional correlation time is equal to the phase memory time determined by ESE. In the fast motional limit, the motional correlation time is proportional to the no motion spectral second moment divided by the ESE phase memory time. ESE offers a convenient method of studying motion, electron transfer, conductivity, etc. in a variety of systems too complicated for study by ordinary EPR. New systems for study by ESE include biological samples, organic polymers, liquid solutions of radicals with unresolved hyperfine, etc. When motion modulates large anisotropic hyperfine couplings, ESE measurements of the phase memory time are sensitive to modulation of pseudosecular hyperfine interactions

  1. Determination of crystal oscillatory spectra by internal friction data spectroscopic analysis

    International Nuclear Information System (INIS)

    Zaykin, Yu.A.

    1998-01-01

    Technique for relaxation spectra determination on the basis of internal friction averaging over relaxation frequencies is developed. It is shown that mathematically the problem is reduced to solution of the first type Fredholm integral equation. Impurity oscillatory spectra in alpha-iron, molybdenum and Fe-Cr-Ni alloy are obtained. (author)

  2. Prototype testing and analysis of a novel internal combustion linear generator integrated power system

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Zhaoping; Chang, Siqin [School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China)

    2010-04-15

    A novel four-stroke free-piston engine equipped with a linear electric generator (namely internal combustion linear generator integrated power system) is proposed in this paper to achieve efficient energy conversion from fuel to electricity. Unique features of the novel power system are presented and their effects on the continuous running are discussed, along with potential advantages and disadvantages compared to conventional engines. A single cylinder, gasoline and spark ignition prototype is fabricated with reference to the geometric and control parameters of an existing conventional four-stroke engine. Stable running of the prototype is realized, and a 2.2 kW average output power with the generating efficiency of 32% has been obtained up to now. The feasibility and performance of the proposed design are verified. Detailed testing results from the continuous running prototype are analyzed in this paper for giving insight into the performance and dynamic behaviors of the novel power system. (author)

  3. Next Generation Safeguards Initiative Workshop on Enhanced Recruiting for International Safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Pepper,S.; Rosenthal, M.; Fishbone, L.; Occhiogrosso, D.; Carroll, C.; Dreicer, M.; Wallace, R.; Rankhauser, J.

    2008-10-22

    In 2007, the National Nuclear Security Administration's Office of Nonproliferation and International Security (NA-24) completed a yearlong review of the challenges facing the international safeguards system today and over the next 25 years. The study found that without new investment in international safeguards, the U.S. safeguards technology base, and our ability to support International Atomic Energy Agency (IAEA) safeguards, will continue to erode and soon may be at risk. To reverse this trend, the then U.S. Secretary of Energy, Samuel Bodman, announced at the 2007 IAEA General Conference that the Department of Energy (DOE) would launch the Next Generation Safeguards Initiative (NGSI). He stated 'IAEA safeguards must be robust and capable of addressing proliferation threats. Full confidence in IAEA safeguards is essential for nuclear power to grow safely and securely. To this end, the U.S. Department of Energy will seek to ensure that modern technology, the best scientific expertise, and adequate resources are available to keep pace with expanding IAEA responsibilities.' To meet this goal, the NGSI objectives include the recruitment of international safeguards experts to work at the U.S. national laboratories and to serve at the IAEA's headquarters. Part of the latter effort will involve enhancing our existing efforts to place well-qualified Americans in a sufficient number of key safeguards positions within the IAEA's Department of Safeguards. Accordingly, the International Safeguards Project Office (ISPO) at Brookhaven National Laboratory (BNL) hosted a Workshop on Enhanced Recruiting for International Safeguards (ERIS) on October 22 and 23, 2008. The ISPO used a workshop format developed earlier with Sonalysts, Inc., that was followed at the U.S. Support Program's (USSP's) technology road-mapping sessions. ISPO invited participants from the U.S. DOE, the IAEA, the U.S. national laboratories, private industry, academia, and

  4. Third International Meeting on Next Generation Safeguards: Safeguards-by-Design at Enrichment Facilities

    International Nuclear Information System (INIS)

    Long, Jon D.; McGinnis, Brent R.; Morgan, James B.; Whitaker, Michael; Lockwood, Dunbar; Shipwash, Jacqueline L.

    2011-01-01

    The Third International Meeting on Next Generation Safeguards (NGS3) was hosted by the U.S. Department of Energy (DOE)/National Nuclear Security Administration's (NNSA) Office of Nonproliferation and International Security (NIS) in Washington, D.C. on 14-15 December 2010; this meeting focused on the Safeguards-by-Design (SBD) concept. There were approximately 100 participants from 13 countries, comprised of safeguards policy and technical experts from government and industry. Representatives also were present from the Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC), the European Atomic Energy Agency (Euratom), and the International Atomic Energy Agency (IAEA). The primary objective of this meeting was to exchange views and provide recommendations on implementation of the SBD concept for four specific nuclear fuel cycle facility types: gas centrifuge enrichment plants (GCEPs), GEN III and GEN IV reactors, aqueous reprocessing plants, and mixed oxide fuel fabrication facilities. The general and facility-specific SBD documents generated from the four working groups, which were circulated for comment among working group participants, are intended to provide a substantive contribution to the IAEA's efforts to publish SBD guidance for these specific types of nuclear facilities in the near future. The IAEA has described the SBD concept as an approach in which 'international safeguards are fully integrated into the design process of a new nuclear facility from the initial planning through design, construction, operation, and decommissioning.' As part of the Next Generation Safeguards Initiative (NGSI), the DOE is working to establish SBD as a global norm through DOE laboratory studies, international workshops, engagement with industry and the IAEA, and setting an example through its use in new nuclear facilities in the United States. This paper describes the discussion topics and final recommendations of the Enrichment Facilities Working

  5. Impact of financial institution environmental guidelines on international power generation projects

    International Nuclear Information System (INIS)

    Macak, J.J. III; Schott, G.A.

    1995-01-01

    Where financing is concerned, two major players for US based international power projects are The World Bank and the Export-Import Bank of the US (Ex-Im Bank). The concern for environmental protection is a global issue, yet many countries still have no enforceable environmental regulations for power generation facilities. In the past, many projects were developed with little or no environmental controls. However, designing a power generation project to meet The World Bank environmental guidelines is now generally regarded as standard practice for independent power projects in the developing world (Price et al, 1994). The World Bank standards are mandatory for projects financed by The World Bank, through the International Finance Corporation (IFC), or associated programs like the Expanded Cofinancing Program of the International Bank for Reconstruction and Development (IBRD). The Ex-Im Bank has recently established new environmental procedures and guidelines that went into effect on February 1, 1995. In order to avoid a competitive disadvantage for US exporters and still provide a means for global environmental protection, Ex-Im Bank has taken a leadership role in encouraging the adoption of common environmental procedures and standards by leading export credit agencies around the world. Until such procedures are established, Ex-Im Bank is seeking to establish common lines in specific cases with the Organization for Economic Cooperation and Development (OECD) on environmental standards for appropriate projects (Ex-Im, 1994)

  6. Analyses of internal tides generation and propagation over a Gaussian ridge in laboratory and numerical experiments

    Science.gov (United States)

    Dossmann, Yvan; Paci, Alexandre; Auclair, Francis; Floor, Jochem

    2010-05-01

    Internal tides are suggested to play a major role in the sustaining of the global oceanic circulation [1][5]. Although the exact origin of the energy conversions occurring in stratified fluids is questioned [2], it is clear that the diapycnal energy transfers provided by the energy cascade of internal gravity waves generated at tidal frequencies in regions of steep bathymetry is strongly linked to the general circulation energy balance. Therefore a precise quantification of the energy supply by internal waves is a crucial step in forecasting climate, since it improves our understanding of the underlying physical processes. We focus on an academic case of internal waves generated over an oceanic ridge in a linearly stratified fluid. In order to accurately quantify the diapycnal energy transfers caused by internal waves dynamics, we adopt a complementary approach involving both laboratory and numerical experiments. The laboratory experiments are conducted in a 4m long tank of the CNRM-GAME fluid mechanics laboratory, well known for its large stratified water flume (e.g. Knigge et al [3]). The horizontal oscillation at precisely controlled frequency of a Gaussian ridge immersed in a linearly stratified fluid generates internal gravity waves. The ridge of e-folding width 3.6 cm is 10 cm high and spans 50 cm. We use PIV and Synthetic Schlieren measurement techniques, to retrieve the high resolution velocity and stratification anomaly fields in the 2D vertical plane across the ridge. These experiments allow us to get access to real and exhaustive measurements of a wide range of internal waves regimes by varying the precisely controlled experimental parameters. To complete this work, we carry out some direct numerical simulations with the same parameters (forcing amplitude and frequency, initial stratification, boundary conditions) as the laboratory experiments. The model used is a non-hydrostatic version of the numerical model Symphonie [4]. Our purpose is not only to

  7. International Conference on Solar Concentrators for the Generation of Electricity or Hydrogen: Book of Abstracts

    Energy Technology Data Exchange (ETDEWEB)

    McConnell, R.; Symko-Davies, M.; Hayden, H.

    2005-05-01

    The International Conference on Solar Concentrators for the Generation of Electricity or Hydrogen provides an opportunity to learn about current significant research on solar concentrators for generating electricity or hydrogen. The conference will emphasize in-depth technical discussions of recent achievements in technologies that convert concentrated solar radiation to electricity or hydrogen, with primary emphasis on photovoltaic (PV) technologies. Very high-efficiency solar cells--above 37%--were recently developed, and are now widely used for powering satellites. This development demands that we take a fresh look at the potential of solar concentrators for generating low-cost electricity or hydrogen. Solar electric concentrators could dramatically overtake other PV technologies in the electric utility marketplace because of the low capital cost of concentrator manufacturing facilities and the larger module size of concentrators. Concentrating solar energy also has advantages for th e solar generation of hydrogen. Around the world, researchers and engineers are developing solar concentrator technologies for entry into the electricity generation market and several have explored the use of concentrators for hydrogen production. The last conference on the subject of solar electric concentrators was held in November of 2003 and proved to be an important opportunity for researchers and developers to share new and crucial information that is helping to stimulate projects in their countries.

  8. Internalizing externalities of electricity generation: An analysis with MESSAGE-MACRO

    International Nuclear Information System (INIS)

    Klaassen, Ger; Riahi, Keywan

    2007-01-01

    This paper examines the global impacts of a policy that internalizes the external costs (related to air pollution damage, excluding climate costs) of electricity generation using a combined energy systems and macroeconomic model. Starting point are estimates of the monetary damage costs for SO 2 , NO X , and PM per kWh electricity generated, taking into account the fuel type, sulfur content, removal technology, generation efficiency, and population density. Internalizing these externalities implies that clean and advanced technologies increase their share in global electricity production. Particularly, advanced coal power plants, natural gas combined cycles, natural gas fuel cells, wind and biomass technologies gain significant market shares at the expense of traditional coal- and gas-fired plants. Global carbon dioxide emissions are lowered by 3% to 5%. Sulfur dioxide emissions drop significantly below the already low level. The policy increases the costs of electricity production by 0.2 (in 2050) to 1.2 Euro cent/kWh (in 2010). Gross domestic product losses are between 0.6% and 1.1%. They are comparatively high during the initial phase of the policy, pointing to the need for a gradual phasing of the policy

  9. Generation of 2.5 μm and 4.6 μm Dispersive Waves in Kagome Photonic Crystal Fiber with Plasma Production

    Institute of Scientific and Technical Information of China (English)

    Tian-Qi Zhao; Meng Li; Dong Wei; Xin Ding; Gui-Zhong Zhang; Jian-Quan Yao

    2017-01-01

    We report our numerical simulation on dispersive waves (DWs) generated in the Kr-filled Kagome hollow-core photonic crystal fiber,by deploying the unidirectional pulse propagation equation.Relatively strong dispersive waves are simultaneously generated at 2.5μm and 4.6μm.It is deciphered that the interplay between plasma currents due to Kr ionization and nonlinear effects plays a key role in DW generation.Remarkably,this kind of DW generation is corroborated by the plasma-corrected phase-matching condition.

  10. Phenotype characterization of embryoid body structures generated by a crystal comet effect tail in an intercellular cancer collision scenario

    Directory of Open Access Journals (Sweden)

    Diaz JA

    2012-01-01

    Full Text Available Jairo A Diaz, Mauricio F MurilloDepartment of Pathology, Hospital Departmental Villavicencio, Hospital Departmental Granada, Medicine School, University Cooperative of Colombia, Villavicencio, Meta, ColombiaAbstract: Cancer is, by definition, the uncontrolled growth of autonomous cells that eventually destroy adjacent tissues and generate architectural disorder. However, this concept cannot be totally true. In three well documented studies, we have demonstrated that cancer tissues produce order zones that evolve over time and generate embryoid body structures in a space-time interval. The authors decided to revise the macroscopic and microscopic material in well-developed malignant tumors in which embryoid bodies were identified to determine the phenotype characterization that serves as a guideline for easy recognition. The factors responsible for this morphogenesis are physical, bioelectric, and magnetic susceptibilities produced by crystals that act as molecular designers for the topographic gradients that guide the surrounding silhouette and establish tissue head-tail positional identities. The structures are located in amniotic-like cavities and show characteristic somite-like embryologic segmentation. Immunophenotypic study has demonstrated exclusion factor positional identity in relation to enolase-immunopositive expression of embryoid body and human chorionic gonadotropin immunopositivity exclusion factor expression in the surrounding tissues. The significance of these observations is that they can also be predicted by experimental image data collected by the Large Hadron Collider (LHC accelerator at the European Organization for Nuclear Research, in which two-beam subatomic collision particles in the resulting debris show hyperorder domains similar to those identified by us in intercellular cancer collisions. Our findings suggest that we are dealing with true reverse biologic system information in an activated collective cancer stem cell

  11. Control strategy on the double-diffusive convection in a nanofluid layer with internal heat generation

    Science.gov (United States)

    Mokhtar, N. F. M.; Khalid, I. K.; Siri, Z.; Ibrahim, Z. B.; Gani, S. S. A.

    2017-10-01

    The influences of feedback control and internal heat source on the onset of Rayleigh-Bénard convection in a horizontal nanofluid layer is studied analytically due to Soret and Dufour parameters. The confining boundaries of the nanofluid layer (bottom boundary-top boundary) are assumed to be free-free, rigid-free, and rigid-rigid, with a source of heat from below. Linear stability theory is applied, and the eigenvalue solution is obtained numerically using the Galerkin technique. Focusing on the stationary convection, it is shown that there is a positive thermal resistance in the presence of feedback control on the onset of double-diffusive convection, while there is a positive thermal efficiency in the existence of internal heat generation. The possibilities of suppress or augment of the Rayleigh-Bénard convection in a nanofluid layer are also discussed in detail.

  12. Total internal reflection second-harmonic generation: probing the alkane water interface

    International Nuclear Information System (INIS)

    Conboy, J.C.; Daschbach, J.L.; Richmond, G.L.

    1994-01-01

    Total internal reflection Second-Harmonic Generation (SHG) has been used to study a series of neat n-alkane/water interfaces. Polarization and incident angular-dependent measurements of the SH response show good agreement with theoretical predictions. Analysis of the incident and polarization angular-dependent SH response allows for determination of the nonlinear optical properties of molecules comprising the interfacial region. Based on Kleinman symmetry, the measured surface nonlinear susceptibilities suggest a high degree of interfacial order for octane and decane with less order indicated by the odd carbon n-alkanes examined, heptane and nonane. The SH response in reflection and transmission has been measured under a Total Internal Reflection (TIR) of the fundamental. The measured nonlinear susceptibilities in each case are found to be identical. (orig.)

  13. Finite element simulations of internal stresses generated during the ferroelastic deformation of NiTi bodies

    International Nuclear Information System (INIS)

    Manach, P.Y.; Favier, D.; Rio, G.

    1996-01-01

    The aim of this paper is to analyse the generation of internal stresses during the predeformation of NiTi shape memory alloys in the martensitic state. This allows to determine the initial stress state in which the material will transform during the shape memory effect due to heating consecutively to this prestrain. In that way a three-dimensional finite element model of the deformation of shape memory alloys has been developed, the constitutive law being defined using an elastohysteresis tensor model. The influence of behavioural and geometrical factors are illustrated considering the numerical simulation of different cases of practical importance for industrial applications : the study of the bending behaviour of a NiTi cantilever beam as well as the study of the swelling of a pipe connection under both uniform and non uniform internal displacement fields. (orig.)

  14. Internal fire analysis screening methodology for the Salem Nuclear Generating Station

    International Nuclear Information System (INIS)

    Eide, S.; Bertucio, R.; Quilici, M.; Bearden, R.

    1989-01-01

    This paper reports on an internal fire analysis screening methodology that has been utilized for the Salem Nuclear Generating Station (SNGS) Probabilistic Risk Assessment (PRA). The methodology was first developed and applied in the Brunswick Steam Electric Plant (BSEP) PRA. The SNGS application includes several improvements and extensions to the original methodology. The SNGS approach differs significantly from traditional fire analysis methodologies by providing a much more detailed treatment of transient combustibles. This level of detail results in a model which is more usable for assisting in the management of fire risk at the plant

  15. The International Geomagnetic Reference Field (IGRF) generation 12: BGS candidates and final models

    OpenAIRE

    Beggan, Ciaran D.; Hamilton, Brian; Taylor, Victoria; Macmillan, Susan; Thomson, Alan

    2015-01-01

    The International Geomagnetic Reference Field (IGRF) model is a reference main field magnetic model updated on a quinquennial basis. The latest revision (generation 12) was released in January 2015. The IGRF-12 consists of a definitive model (DGRF2010) of the main field for 2010.0, a model for the field at 2015.0 (IGRF2015) and a prediction of secular variation (IGRF-12 SV) for the forthcoming five years until 2020.0. The remaining coefficients of IGRF-12 are unchanged from IGRF-11. Nin...

  16. The Next Generation of Axion Helioscopes: The International Axion Observatory (IAXO)

    DEFF Research Database (Denmark)

    Vogel, J.K.; Armengaud, E.; Avignone, F.T.

    2015-01-01

    The International Axion Observatory (IAXO) is a proposed 4th-generation axion helioscope with the primary physics research goal to search for solar axions via their Primakoff conversion into photons of 1 – 10 keV energies in a strong magnetic field. IAXO will achieve a sensitivity to the axion-ph...... low background x-ray detectors. The magnet will be built into a structure with elevation and azimuth drives that will allow solar tracking for 12hours each day. This contribution is a summary of our papers [1–3] and we refer to these for further details....

  17. Using the International Space Station (ISS) Oxygen Generation Assembly (OGA) Is Not Feasible for Mars Transit

    Science.gov (United States)

    Jones, Harry W.

    2016-01-01

    A review of two papers on improving the International Space Station (ISS) Oxygen Generation Assembly (OGA) shows that it would not save substantial mass on a Mars transit. The ISS OGA requires redesign for satisfactory operation, even for the ISS. The planned improvements of the OGA for ISS would not be sufficient to make it suitable for Mars, because Mars transit life support has significantly different requirements than ISS. The OGA for Mars should have lower mass, better reliability and maintainability, greater safety, radiation hardening, and capability for quiescent operation. NASA's methodical, disciplined systems engineering process should be used to develop the appropriate system.

  18. Enhanced piezoelectric operation of NiO/GaN heterojunction generator by suppressed internal carrier screening

    International Nuclear Information System (INIS)

    Jeong, Dae Kyung; Kang, Jin-Ho; Ryu, Sang-Wan; Ha, Jun-Seok

    2017-01-01

    A NiO/GaN heterojunction piezoelectric generator was fabricated, and the improvement in device performance was analyzed. The electrical properties of NiO were varied by regulating the gas environment during sputtering. An optimized NiO layer was adopted for high piezoelectric voltage generation. Internal carrier screening was revealed to be the dominant mechanism degrading the piezoelectric performance, necessitating the suppression of carrier screening. The highly resistive NiO layer was advantageous in the suppression of carrier transport across the junction that screened the piezoelectric field. The maximum piezoelectric voltage and current density values obtained were 7.55 V and 1.14 µ A cm −2 , respectively. The power obtained was sufficient to operate a light-emitting diode combined with a charging circuit. (paper)

  19. Thermally radiative three-dimensional flow of Jeffrey nanofluid with internal heat generation and magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Shehzad, S.A., E-mail: ali_qau70@yahoo.com [Department of Mathematics, Comsats Institute of Information Technology, Sahiwal 57000 (Pakistan); Abdullah, Z. [Department of Mathematics, Comsats Institute of Information Technology, Sahiwal 57000 (Pakistan); Alsaedi, A. [Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Faculty of Science, King Abdulaziz University, P. O. Box 80257, Jeddah 21589 (Saudi Arabia); Abbasi, F.M. [Department of Mathematics, Comsats Institute of Information Technology, Islamabad 44000 (Pakistan); Hayat, T. [Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Faculty of Science, King Abdulaziz University, P. O. Box 80257, Jeddah 21589 (Saudi Arabia); Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan)

    2016-01-01

    This research work addresses the three-dimensional hydromagnetic flow of Jeffrey fluid with nanoparticles. Flow is generated by a bidirectional stretching surface. The effects of thermal radiation and internal heat generation are encountered in energy expressions. More realistic convective boundary conditions at the surface are employed instead of constant surface temperature and mass species conditions. Boundary layer assumptions lead to the governing non-linear mathematical model. Resulting equations through momentum, energy and mass species are made dimensionless using suitable variables. The solution expressions of dimensionless velocities, temperature and nanoparticle concentration have been computed for the convergent series solutions. The impacts of interesting parameters on the dimensionless quantities are displayed and interpreted. The values of physical quantities are computed and analyzed. - Highlights: • Three-dimensional hydromagnetic flow of Jeffrey nanofluid is considered. • Brownian motion and thermophoresis effects are encountered. • Heat transfer analysis is performed with thermal radiation. • Results are plotted and visualized.

  20. Cost of generating tritium internal and external to a tokamak hybrid reactor

    International Nuclear Information System (INIS)

    Crotzer, M.E.; Heck, F.M.; Steinke, K.C.

    1981-01-01

    The costs associated with producing tritium internal and external to a thorium-based tokamak hybrid are estimated for a number of scenarios and the resulting impact on the symbiotic system cost of electricity calculated. For tritium generation within the hybrid, both continuous and batch production is analyzed. For external production, the lithium-bearing blanket is replaced with thorium and the tritium is generated in the client fission reactors. Continuous tritium production within the hybrid is found to increase the cost of electricity from 1.4 to 4.0 mills/kW-h. Batch tritium production can increase the cost of electricity by 10 mills/kW-h. Producing tritium outside the hybrid, and thereby enhancing client support, increases the cost of electricity from 1.8 to 4.1 mills/kW-h

  1. Book of abstracts: International Conference on Smart Energy Systems and 4th Generation District Heating

    DEFF Research Database (Denmark)

    , which takes a sole focus on the electricity sector, the smart energy systems approach includes the entire energy system in its identification of suitable energy infrastructure designs and operation strategies. Focusing solely on the smart electricity grid often leads to the definition of transmission......It is a great pleasure to welcome you to the first International Conference on Smart Energy Systems and 4th Generation District Heating at Aalborg University, Copenhagen Campus on 25-26 August 2015. The conference is organised by the 4DH Strategic Research Centre in collaboration with Aalborg...... University and offers more than 70 presentations in 3 parallel sessions with more than 180 participants from 25 countries around the world. The aim is to present and discuss scientific findings and industrial experiences related to the development of Smart Energy Systems and future 4th Generation District...

  2. Start up system for hydrogen generator used with an internal combustion engine

    Science.gov (United States)

    Houseman, J.; Cerini, D. J. (Inventor)

    1977-01-01

    A hydrogen generator provides hydrogen rich product gases which are mixed with the fuel being supplied to an internal combustion engine for the purpose of enabling a very lean mixture of that fuel to be used, whereby nitrous oxides emitted by the engine are minimized. The hydrogen generator contains a catalyst which must be heated to a pre-determined temperature before it can react properly. To simplify the process of heating up the catalyst at start-up time, either some of the energy produced by the engine such as engine exhaust gas, or electrical energy produced by the engine, or the engine exhaust gas may be used to heat up air which is then used to heat the catalyst.

  3. Recovery of amplitude dependent internal friction in plastically deformed LiF single crystals

    International Nuclear Information System (INIS)

    Koshimizu, S.

    1977-01-01

    The internal friction due to is studied interactions between point defects and dislocations produced in pure LiF single crystais by plastic deformation. The recovery of amplitude dependent damping is investigated in these crystais in the low frequency range. The logarithmic decrement is measured as a function of strain amplitude at several different temperatures in the range 8C - 35C in order to observe thermal breakaway. The results were interpred according to the theory developed by Granato and Lucke. Systematic measurements are also been carried out to determine the logarithmic decrement as a function of time at different temperatures, after driving the specimens at high strains amplitudes, yelding the following results: I) there is a recovery of the amplitude dependent damping upon removal of the high strain excitations, and II) the Kinetic of the recovery follows initially a t sup(2/3) ageing law, changing to tsup(1/3) afterwards [pt

  4. Effects of multi-photon interferences from internally generated fields in strongly resonant systems

    International Nuclear Information System (INIS)

    Deng, Lu; Payne, Marvin G.; Garrett, William R.

    2006-01-01

    In studies of various nonlinear optical phenomena, strong resonant features in the atomic or molecular response to multi-photon driven processes have been used to greatly enhance the visibility of otherwise weak higher-order processes. However, there are well defined circumstances where a multi-photon-resonant response of a target system leads to the generation of one or more new electromagnetic fields that can drastically change the overall system response from what would be expected from the imposed laser fields alone. New effects can occur and dominate some aspects of the nonlinear optical response because of the constructive or destructive interference between transition amplitudes along multiple excitation pathways between a given set of optically coupled states, where one of the pathways involve internally generated field(s). Under destructive interference some resonant enhancements can become completely canceled (suppressed). This review focuses on the class of optical interference effects associated with internally generated fields, that have been found to be capable of influencing a very significant number of basic physical phenomena in gas or vapor phase systems. It provides a historical overview of experimental and theoretical developments and a modern understanding of the underlying physics and its various manifestations that include: suppression of multi-photon excitation processes, suppression of stimulated emissions (Raman, hyper-Raman, and optically pumped stimulated emissions), saturation of parametric wave-mixing, pressure and beam-geometry dependent shifting of multi-photon-resonant absorption lines, and the suppression of Autler-Townes splitting and ac-stark shifts. Additionally, optical interference effects in some modern contexts, such as achieving multi-photon induced transparency, establishing single-photon self-interference based induced transparency, and generating entangled single photon states, are reviewed

  5. AGE RELATED DEGRADATION OF STEAM GENERATOR INTERNALS BASED ON INDUSTRY RESPONSES TO GENERIC LETTER 97-06

    International Nuclear Information System (INIS)

    SUBUDHI, M.; SULLIVAN, JR. E.J.

    2002-01-01

    THIS PAPER PRESENTS THE RESULTS OF AN AGING ASSESSMENT OF THE NUCLEAR POWER INDUSTRY RESPONSES TO NRC GENERIC LETTER 97-06 ON THE DEGRADATION OF STEAM GENERATOR INTERNALS EXPERIENCED AT ELECTRICITE DE FRANCE (EDF) PLANTS IN FRANCE AND AT A UNITED STATES PRESSURIZED WATER REACTOR (PWR). WESTINGHOUSE (W), COMBUSTION ENGINEERING (CE), AND BABCOCK AND WILCOX (BW) STEAM GENERATOR MODELS, CURRENTLY IN SERVICE AT U.S. NUCLEAR POWER PLANTS, POTENTIALLY COULD EXPERIENCE DEGRADATION SIMILAR TO THATFOUND AT EDF PLANTS AND THE U.S. PLANT. THE STEAM GENERATORS IN MANY OF THE U.S. PWRS HAVE BEEN REPLACED WITH STEAM GENERATORS WITH STEAM GENERATORS WITH IMPROVED DESIGNS AND MATERIALS. THESE REPLACEMENT STEAM GENERATORS HAVE BEEN MANUFACTURED IN THE U.S. AND ABROAD. DURING THIS ASSESSMENT, EACH OF THE THREE OWNERS GROUPS (W,CE, AND BW) IDENTIFIED FOR ITS STEAM GENERATOR, MODELS ALL THE POTENTIAL INTERNAL COMPONENTS THAT ARE VULNERABLE TO DEGRADATION WHILE IN SERVICE. EACH OWNERS GROUPDEVELOPED INSPEC TION AND MONITORING GUIDANCE AND RECOMMENDATIONS FOR ITS PARTICULAR STEAM GENERATOR MODELS. THE NUCLEAR ENERGY INSTITUTE INCORPORATED IN NEI 97-06 STEAM GENERATOR PROGRAM GUIDELINES, A REQUIREMENT TO MONITOR SECONDARY SIDE STEAM GENERATOR COMPONENTS IF THEIR FAILURE COULD PREVENT THE STEAM GENERATOR FROM FULFILLING ITS INTENDED SAFETY-RELATED FUNCTION. LICENSEES INDICATED THAT THEY IMPLEMENTED OR PLANNED TO IMPLEMENT, AS APPROPRIATE FOR THEIR STEAM GENERATORS, THEIR OWNERS GROUPRECOMMENDATIONS TO ADDRESS THE LONG-TERM EFFECTS OF THE POTENTIAL DEGRADATION MECHANISMS ASSOCIATED WITH THE STEAM GENERATOR INTERNALS

  6. Generation of a mid-infrared broadband polarized supercontinuum in As2Se3 photonic crystal fibers

    International Nuclear Information System (INIS)

    Wang Xiao-Yan; Li Shu-Guang; Liu Shuo; Yin Guo-Bing; Li Jian-She

    2012-01-01

    A simplified structure of birefringent chalcogenide As 2 Se 3 photonic crystal fiber (PCF) is designed. Properties of birefringence, polarization extinction ratio, chromatic dispersion, nonlinear coefficient, and transmission are studied by using the multipole method, the finite-difference beam propagation method, and the adaptive split-step Fourier method. Considering that the zero dispersion wavelength of our proposed fiber is about 4 μm, we have analysed the mechanism of spectral broadening in PCFs with different pitches in detail, with femtosecond pulses at a wavelength of 4 μm as the pump pulses. Especially, mid-infrared broadband polarized supercontinuums are obtained in a 3-cm PCF with an optimal pitch of 2 μm. Their spectral width at −20 dB reaches up to 12 μm. In the birefringent PCF, we find that the supercontinuum generation changes with the pump alignment angle. Research results show that no coupling between eigenpolarization modes are observed at the maximum average power (i.e., 37 mW), which indicates that the polarization state is well maintained. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  7. Highly-nonlinear polarization-maintaining As2Se3-based photonic quasi-crystal fiber for supercontinuum generation

    Science.gov (United States)

    Zhao, Tongtong; Lian, Zhenggang; Benson, Trevor; Wang, Xin; Zhang, Wan; Lou, Shuqin

    2017-11-01

    We propose an As2Se3-based photonic quasi-crystal fiber (PQF) with high nonlinearity and birefringence. By optimizing the structure parameters, a nonlinear coefficient up to 2079 W-1km-1 can be achieved at the wavelength of 2 μm; the birefringence reaches up to the order of 10-2 due to the introduction of large circular air holes in the cladding. Using an optical pulse with a peak power of 6 kW, a pulse width of 150 fs, and a central wavelength of 2.94 μm as the pump pulse, a mid-infrared polarized supercontinuum is obtained by using a 15 mm long PQF. The spectral width for x- and y-polarizations covers 1 μm-10.2 μm and 1 μm-12.5 μm, respectively. The polarization state can be well maintained when the incident angle of the input pulse changes within ±2°. The proposed PQF, with high nonlinear coefficient and birefringence, has potential applications in mid-infrared polarization-maintaining supercontinuum generation.

  8. Emissions trading in the real world : Ontario Power Generation's domestic and international trading activities

    International Nuclear Information System (INIS)

    Jantzi, B.

    2001-01-01

    In this presentation, the author discussed Ontario Power Generation's voluntary commitment to stabilize carbon dioxide equivalent emissions at 1990 levels. To do so, Ontario Power Generation is implementing a series of green energy initiatives, a corporate tree planting program, internal energy efficiency, and an emission reduction trading (ERT). The emphasis was placed on emission trading, where Ontario Power Generation is a leader in the field of greenhouse gas, nitrogen oxide and sulphur dioxide trading in Canada. The approach to trading adopted was explained, with the specifics provided for each of the different categories of emissions. Some examples further illustrated the process. The outlook for the future was outlined, with plans for the geological sequestration of carbon dioxide and enhanced oil recovery, low nitrogen oxide gasoline additive. The benefits of emission trading were discussed from the perspective of Ontario Power Generation and the environment, such as allowing real reductions in emissions in a cost effective manner, enhanced risk management, investments in emissions reductions. The author argued that emission reduction is the way of the future, representing the only way in which the greenhouse gas emissions reductions required to minimize global climate change will be accomplished

  9. Next Generation Safeguards Initiative Workshop on Enhanced Recruiting for International Safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Pepper,S.E.; Rosenthal, M.D.; Fishbone, L.G.; Occhogrosso, D.M.; Lockwood, D.; Carroll, C.J.; Dreicer, M.; Wallace, R.; Fankhauser, J.

    2009-07-12

    Brookhaven National Laboratory (BNL) hosted a Workshop on Enhanced Recruiting for International Safeguards October 22 and 23, 2008. The workshop was sponsored by DOE/NA-243 under the Next Generation Safeguards Initiative (NGSI). Placing well-qualified Americans in sufficient number and in key safeguards positions within the International Atomic Energy Agency’s (IAEA’s) Department of Safeguards is an important U.S. non-proliferation objective. The goal of the NGSI Workshop on Enhanced Recruiting for International Safeguards was to improve U.S. efforts to recruit U.S. citizens for IAEA positions in the Department of Safeguards. The participants considered the specific challenges of recruiting professional staff, safeguards inspectors, and managers. BNL’s International Safeguards Project Office invited participants from the U.S. Department of Energy, the IAEA, U.S. national laboratories, private industry, academia, and professional societies who are either experts in international safeguards or who understand the challenges of recruiting for technical positions. A final report for the workshop will be finalized and distributed in early 2009. The main finding of the workshop was the need for an integrated recruitment plan to take into account pools of potential candidates, various government and private agency stakeholders, the needs of the IAEA, and the NGSI human capital development plan. There were numerous findings related to and recommendations for maximizing the placement of U.S. experts in IAEA Safeguards positions. The workshop participants offered many ideas for increasing the pool of candidates and increasing the placement rate. This paper will provide details on these findings and recommendations

  10. Next Generation Safeguards Initiative Workshop on Enhanced Recruiting for International Safeguards

    International Nuclear Information System (INIS)

    Pepper, S.E.; Rosenthal, M.D.; Fishbone, L.G.; Occhogrosso, D.M.; Lockwood, D.; Carroll, C.J.; Dreicer, M.; Wallace, R.; Fankhauser, J.

    2009-01-01

    Brookhaven National Laboratory (BNL) hosted a Workshop on Enhanced Recruiting for International Safeguards October 22 and 23, 2008. The workshop was sponsored by DOE/NA-243 under the Next Generation Safeguards Initiative (NGSI). Placing well-qualified Americans in sufficient number and in key safeguards positions within the International Atomic Energy Agency's (IAEA's) Department of Safeguards is an important U.S. non-proliferation objective. The goal of the NGSI Workshop on Enhanced Recruiting for International Safeguards was to improve U.S. efforts to recruit U.S. citizens for IAEA positions in the Department of Safeguards. The participants considered the specific challenges of recruiting professional staff, safeguards inspectors, and managers. BNL's International Safeguards Project Office invited participants from the U.S. Department of Energy, the IAEA, U.S. national laboratories, private industry, academia, and professional societies who are either experts in international safeguards or who understand the challenges of recruiting for technical positions. A final report for the workshop will be finalized and distributed in early 2009. The main finding of the workshop was the need for an integrated recruitment plan to take into account pools of potential candidates, various government and private agency stakeholders, the needs of the IAEA, and the NGSI human capital development plan. There were numerous findings related to and recommendations for maximizing the placement of U.S. experts in IAEA Safeguards positions. The workshop participants offered many ideas for increasing the pool of candidates and increasing the placement rate. This paper will provide details on these findings and recommendations

  11. Investigation of structural phase transition in strontium titanate single crystal by methods of generation of coherent and incoherent second optical harmonics

    International Nuclear Information System (INIS)

    Mishina, E.D.; Morozov, A.I.; Sigov, A.S.; Sherstyuk, N.Eh.; Aktsipetrov, O.A.; Lemanov, V.V.; Rasing, Th.

    2002-01-01

    The surface phase transition in the SrTiO 3 crystal is studied through the method of the second optical harmonic generation. The peculiarities in the nonlinear-optical response are identified at the temperature of T* = 145 K, which by 40 K exceeds the T c temperature of the structural phase transition in the crystal volume. The phenomenon of the nonlinear critical opalescence, caused by availability of the point defects, is studied. The second harmonic field and critical opalescence intensity are calculated on the basis of the phenomenological model of the nonlinear-optical processes with application of the Landau phase transition theory [ru

  12. Numerical and experimental investigation of melting with internal heat generation within cylindrical enclosures

    Energy Technology Data Exchange (ETDEWEB)

    Amber Shrivastava; Brian Williams; Ali S. Siahpush; Bruce Savage; John Crepeau

    2014-06-01

    There have been significant efforts by the heat transfer community to investigate the melting phenomenon of materials. These efforts have included the analytical development of equations to represent melting, numerical development of computer codes to assist in modeling the phenomena, and collection of experimental data. The understanding of the melting phenomenon has application in several areas of interest, for example, the melting of a Phase Change Material (PCM) used as a thermal storage medium as well as the melting of the fuel bundle in a nuclear power plant during an accident scenario. The objective of this research is two-fold. First a numerical investigation, using computational fluid dynamics (CFD), of melting with internal heat generation for a vertical cylindrical geometry is presented. Second, to the best of authors knowledge, there are very limited number of engineering experimental results available for the case of melting with Internal Heat Generation (IHG). An experiment was performed to produce such data using resistive, or Joule, heating as the IHG mechanism. The numerical results are compared against the experimental results and showed favorable correlation. Uncertainties in the numerical and experimental analysis are discussed. Based on the numerical and experimental analysis, recommendations are made for future work.

  13. Development of the Next Generation Gas Trap for the Space Station Internal Thermal Control System

    Science.gov (United States)

    Leimkuehler, Thomas O.; Spelbring, Chris; Reeves, Daniel R.; Holt, James M.

    2003-01-01

    The current dual-membrane gas trap is designed to remove non-condensed gases (NCG) from the Internal Thermal Control System (ITCS) coolant on board the International Space Station (ISS). To date it has successfully served its purpose of preventing depriming, overspeed, and shutdown of the ITCS pump. However, contamination in the ITCS coolant has adversely affected the gas venting rate and lifetime of the gas trap, warranting a development effort for a next-generation gas trap. Design goals are to meet or exceed the current requirements to (1) include greater operating ranges and conditions, (2) eliminate reliance on the current hydrophilic tube fabrication process, and (3) increase operational life and tolerance to particulate and microbial growth fouling. In addition, the next generation gas trap will essentially be a 'dropin" design such that no modifications to the ITCS pump package assembly (PPA) will be required, and the implementation of the new design will not affect changes to the ITCS operational conditions, interfaces, or software. This paper will present the initial membrane module design and development work which has included (1) a trade study among several conceptual designs, (2) performance modeling of a hydrophobic-only design, and (3) small-scale development test data for the hydrophobic-only design. Testing has shown that the hydrophobic-only design is capable of performing even better than the current dual-membrane design for both steady-state gas removal and gas slug removal.

  14. Anisotropy of hardness and laser damage threshold of unidirectional organic NLO crystal in relation to the internal structure

    International Nuclear Information System (INIS)

    Natarajan, V.; Arivanandhan, M.; Sankaranarayanan, K.; Hayakawa, Y.

    2011-01-01

    Highlights: · Growth rate of the unidirectional organic crystals were measured and the variation in the growth rate was explained based on the attachment energy model. · Anisotropic behaviors of hardness and laser damage threshold of the unidirectional materials were analyzed. · The obtained results were explained based on the crystal structure of the material. - Abstract: Unidirectional benzophenone crystals were grown along , and directions by uniaxially solution crystallization method at ambient temperature. The growth rate of the grown crystals was varied with orientation. The optical absorption coefficients of benzophenone were measured as a function of wavelength. The optical absorption study reveals that the benzophenone crystal has very low absorption in the wavelength range of interest. Moreover, the laser damage threshold and micro hardness for , and oriented unidirectional benzophenone crystals were measured using a Q-switched Nd:YAG laser operating at 1064 nm radiation and Vicker's micro hardness tester, respectively. The laser damage threshold is larger for the and oriented crystals compared to oriented crystal at 1064 nm wavelength. The result is consistent with the hardness variation observed for the three different crystallographic directions of benzophenone crystal. The relation between the laser damage profile and mechanical hardness anisotropy is discussed based on the crystal structure of benzophenone.

  15. Coupling ontology driven semantic representation with multilingual natural language generation for tuning international terminologies.

    Science.gov (United States)

    Rassinoux, Anne-Marie; Baud, Robert H; Rodrigues, Jean-Marie; Lovis, Christian; Geissbühler, Antoine

    2007-01-01

    The importance of clinical communication between providers, consumers and others, as well as the requisite for computer interoperability, strengthens the need for sharing common accepted terminologies. Under the directives of the World Health Organization (WHO), an approach is currently being conducted in Australia to adopt a standardized terminology for medical procedures that is intended to become an international reference. In order to achieve such a standard, a collaborative approach is adopted, in line with the successful experiment conducted for the development of the new French coding system CCAM. Different coding centres are involved in setting up a semantic representation of each term using a formal ontological structure expressed through a logic-based representation language. From this language-independent representation, multilingual natural language generation (NLG) is performed to produce noun phrases in various languages that are further compared for consistency with the original terms. Outcomes are presented for the assessment of the International Classification of Health Interventions (ICHI) and its translation into Portuguese. The initial results clearly emphasize the feasibility and cost-effectiveness of the proposed method for handling both a different classification and an additional language. NLG tools, based on ontology driven semantic representation, facilitate the discovery of ambiguous and inconsistent terms, and, as such, should be promoted for establishing coherent international terminologies.

  16. An Application in Healthcare Sector towards Accounting of Value Added Tax Generated by International Business Transactions

    Directory of Open Access Journals (Sweden)

    Seçkin GÖNEN

    2015-07-01

    Full Text Available The world has become into a single market and geographical boundaries has disappeared due to globalization in international commerce caused by recent rapid technological advancements in our country and internationally. The significance of export incentive is arising day by day in order to countries having a voice in the field in addition to developing market shares and improving competition powers. Besides, considering many times that our country faced with a foreign trade deficit made encouraging exports compulsory. On this basis, Value Added Tax Law numbered 3065, export exemptions made available for exporters are appeared as a successful and efficient implementation. The aim of this study is to reveal applicability of VAT in healthcare sector generated by international business transactions. Through this aim, sample case analysis is used as a qualitative research method. As a result of the research conducted, exemptions of VAT are applied to goods available for sale through inward processing regime. During the importation of raw materials which are going to be used for processing of goods to be exported by suspension system, taxes are paid in importation of raw materials thus paid VAT amounts in regime context are received back from affiliated tax office.

  17. F + centre generation in MgO crystals at high density of excitation by accelerated electrons of subthreshold energy

    Science.gov (United States)

    Annenkov, Y. M.; Surzhikov, A. P.; Surzhikov, V. P.; Pogrebnjak, A. D.

    1981-07-01

    Optical absorption spectra and the angular distribution of annihilated positrons in MgO crystals irradiated by subtreshold superdense electron pulses are measured. The experimental results obtained show the effective contribution of the creation mechanism of non-impact radiation defects in MgO crystals at the highest electron irradiation densities.

  18. Internal Short-Circuiting Phenomena In An Open-Cycle MHD Generator

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Y.; Ishibashi, E. [Hitachi Research Laboratory, Hitachi-shi, Ibaraki-ken (Japan); Kasahara, T.; Kazawa, Y. [Hitachi Works, Hitachi Ltd., Hitachi-shi, Ibaraki-ken (Japan)

    1968-11-15

    The influence of internal electrical leakage due to circulating currents flowing through velocity boundary layers and due to metallic elements in insulating walls (peg walls) is experimentally investigated. For this purpose a combustion-driven MHD generator is utilized. The active part of the generator test section is 60 cm in length with a constant cross-section of 3 x 12 cm{sup 2}. At typical operating conditions about 70 g/s of diesel light oil is burned with oxygen-enriched air, resulting in a thermal input of 3 MW, a fluid velocity of 500 to 700 m/s and a gas temperature of 2700 to 2900 Degree-Sign K at the channel inlet. KOH is used as the seed material. The magnetic field can be raised up to 1.95 Teslas. In the range of lower magnetic fields (B < 0.8T) it is shown that an observed open-circuit voltage agrees well with the theoretical value OBh which is defined in a one-dimensional MHD model. In other words, the circulating currents scarcely affect the open-circuit voltage. The theoretical basis for this fact is obtained by the use of a simple model. Experimental results obtained in several runs using three sets of insulating walls show that thermal boundary layers at water-cooled metals are more conductive than expected and that the open- circuit voltage decreases because of leakage currents flowing through metal pegs, when the internal resistance of the generator is relatively large. Also, it is shown that an alumina coating is effective in reducing the leakage currents. (author)

  19. Absolute non-linear optical coefficients measurements of CsLiB 6O 10 single crystals by second harmonic generation

    Science.gov (United States)

    Sifi, A.; Klein, R. S.; Maillard, A.; Kugel, G. E.; Péter, A.; Polgár, K.

    2003-10-01

    We present absolute measurements of the effective non-linear optical coefficients deff of cesium lithium borate crystals (CsLiB 6O 10, CLBO) by second harmonic generation using a continuous Nd-YAG laser source. The experiments were carried out at room temperature, on crystals cut perpendicular to type I or type II phase matching directions, with two different crystal lengths along the propagation direction. The d36 and d14 non-linear coefficients involved in deff developments are deduced and are shown to be equal as it is predicted by the Kleinman symmetry. Two different compositions prepared by the Czochralski technique from melt with compositions of 1:1:6 and 1:1:5.5 molar ratios of Cs 2O, Li 2O and B 2O 3 are comparatively studied.

  20. Gyrofluid Simulations of Intrinsic Rotation Generation in Reversed Shear Plasmas with Internal Transport Barriers

    Science.gov (United States)

    Jhang, Hogun; Kim, S. S.; Kwon, J. M.; Terzolo, L.; Kim, J. Y.; Diamond, P. H.

    2010-11-01

    It is accepted that the intrinsic rotation is generated via the residual stress, which is non-diffusive components of the turbulent Reynolds stress, without external momentum input. The physics leading to the onset of intrinsic rotation in L- and H- mode plasmas have been elucidated elsewhere. However, the physics responsible for the generation and transport of the intrinsic rotation and its relationship to the formation of internal transport barriers (ITBs) in reversed shear (RS) plasmas have not been explored in detail, which is the main subject in the present work. The revised version of the global gyrofluid code TRB is used for this study. It is found that the large intrinsic rotation (˜10-30% of the ion sound speed depending on ITB characteristics) is generated near the ITB region and propagates into the core. The intrinsic rotation increases linearly as the temperature gradient at ITB position increases, albeit not indefinitely. Key parameters related to the symmetry breaking, such as turbulent intensity and its gradient, the flux surface averaged parallel wavenumber are evaluated dynamically during the ITB formation. In particular, the role of reversed shear and the q-profile curvature is presented in relation to the symmetry breaking in RS plasmas.

  1. Accelerated Electromechanical Modeling of a Distributed Internal Combustion Engine Generator Unit

    Directory of Open Access Journals (Sweden)

    Serhiy V. Bozhko

    2012-07-01

    Full Text Available Distributed generation with a combustion engine prime mover is still widely used to supply electric power in a variety of applications. These applications range from backup power supply systems and combined wind-diesel generation to providing power in places where grid connection is either technically impractical or financially uneconomic. Modelling of such systems as a whole is extremely difficult due to the long-time load profiles needed and the computational difficulty of including small time-constant electrical dynamics with large time-constant mechanical dynamics. This paper presents the development of accelerated, reduced-order models of a distributed internal combustions engine generator unit. Overall these models are shown to achieve a massive improvement in the computational time required for long-time simulations while also achieving an extremely high level of dynamic accuracy. It is demonstrated how these models are derived, used and verified against benchmark models created using established techniques. Throughout the paper the modelling set as a whole, including multi level detail, is presented, detailed and finally summarised into a crucial tool for general system investigation and multiple target optimisation.

  2. Event generation for next to leading order chargino production at the international linear collider

    Energy Technology Data Exchange (ETDEWEB)

    Robens, T.

    2006-10-15

    At the International Linear Collider (ILC), parameters of supersymmetry (SUSY) can be determined with an experimental accuracy matching the precision of next-to-leading order (NLO) and higher-order theoretical predictions. Therefore, these contributions need to be included in the analysis of the parameters. We present a Monte-Carlo event generator for simulating chargino pair production at the ILC at next-to-leading order in the electroweak couplings. We consider two approaches of including photon radiation. A strict fixed-order approach allows for comparison and consistency checks with published semianalytic results in the literature. A version with soft- and hard-collinear resummation of photon radiation, which combines photon resummation with the inclusion of the NLO matrix element for the production process, avoids negative event weights, so the program can simulate physical (unweighted) event samples. Photons are explicitly generated throughout the range where they can be experimentally resolved. In addition, it includes further higher-order corrections unaccounted for by the fixed-order method. Inspecting the dependence on the cutoffs separating the soft and collinear regions, we evaluate the systematic errors due to soft and collinear approximations for NLO and higher-order contributions. In the resummation approach, the residual uncertainty can be brought down to the per-mil level, coinciding with the expected statistical uncertainty at the ILC. We closely investigate the two-photon phase space for the resummation method. We present results for cross sections and event generation for both approaches. (orig.)

  3. Synthesis and physicochemical properties of bis(L-asparaginato) zinc(II): A promising new semiorganic crystal with high laser damage threshold for shorter wavelength generation

    Science.gov (United States)

    Subhashini, R.; Arjunan, S.

    2018-05-01

    An exceedingly apparent nonlinear semiorganic optical crystals of bis(L-asparaginato)zinc(II) [BLAZ], was synthesized by a traditional slow evaporation solution growth technique. The cell parameters were estimated from single crystal X-ray diffraction analysis. Spectroscopic study substantiates the presence of functional groups. The UV spectrum shows the sustenance of wide transparency window and several optical constants, such as extinction coefficient (K), refractive index, optical conductivity and electric susceptibility with real and imaginary parts of dielectric constant were calculated using the transmittance data. The fluorescence emission spectrum of the crystal pronounces red emission. The laser induced surface damage threshold of the crystal was measured using Nd:YAG laser. The output intensity of second harmonic generation was estimated using the Kurtz and Perry powder method. The hardness stability was investigated by Vickers microhardness test. The decomposition and thermal stability of the compound were scrutinized by TGA-DSC studies. Dielectric studies were carried out to anatomize the electrical properties of the crystal. SEM analysis reveals the existence of minute crystallites on the growth surface.

  4. DEVELOPMENT OF THE MODEL OF AN AUTOMATIC GENERATION OF TOTAL AMOUNTS OF COMMISSIONS IN INTERNATIONAL INTERBANK PAYMENTS

    Directory of Open Access Journals (Sweden)

    Dmitry N. Bolotov

    2013-01-01

    Full Text Available The article deals with the main form of international payment - bank transfer and features when it is charging by banks correspondent fees for transit funds in their correspondent accounts. In order to optimize the cost of expenses for international money transfers there is a need to develop models and toolkit of automatic generation of the total amount of commissions in international interbank settlements. Accordingly, based on graph theory, approach to the construction of the model was developed.

  5. Recursive macro generator for the TAS-86 language. First part: the macro generator language. Second part: system internal logics

    International Nuclear Information System (INIS)

    Zraick, Samir

    1970-01-01

    A macro-generator is a translator which is able to interpret and translate a programme written in a macro-language. After a first part presenting the main notions and proposing a brief description of the TAS-86 language, the second part of this research thesis reports the development of the macro-generator language, and notably presents the additional functionalities provided by the macro generator. The development is illustrated by logical flowcharts and programming listings

  6. Bounds of thermal stability of infinite cylindrical structures with non-uniform internal heat generation

    International Nuclear Information System (INIS)

    Gadalla, M.A.

    1992-01-01

    This paper presents an overview analyses of the thermal instability or thermal viability of infinite cylindrical structures with non-linear and non-uniform internal heat generation. The structure may be subjected to different and combined boundary conditions. An analytical solution is obtained for the generalized problem in spite of the non-linearity and the non-homogeneity of the source term. Four case studies with different boundary conditions are presented. The analyses show that the critical parameter for thermal stability may be though of as an altitude of surface below which the cylindrical structure will be thermally stable and performance worthy. The results also show that the bounds of thermal stability of a cylindrical structure system (solid or hollow) is eminently determined by the boundary conditions to which the system is subjected and can significantly alter the life-span of the structure

  7. Influence of an Internally-Generated QBO on Modeled Stratospheric Dynamics and Ozone

    Science.gov (United States)

    Hurwitz, M. M.; Newman, P. A.; Song, I. S.

    2011-01-01

    A GEOS V2 CCM simulation with an internally generated quasi-biennial oscillation (QBO) signal is compared to an otherwise identical simulation without a QBO. In a present-day climate, inclusion of the modeled QBO makes a significant difference to stratospheric dynamics and ozone throughout the year. The QBO enhances variability in the tropics, as expected, but also in the polar stratosphere in some seasons. The modeled QBO also affects the mean stratospheric climate. Because tropical zonal winds in the baseline simulation are generally easterly, there is a relative increase in zonal wind magnitudes in tropical lower and middle stratosphere in the QBO simulation. Extra-tropical differences between the QBO and 'no QBO' simulations thus reflect a bias toward the westerly phase of the QBO: a relative strengthening and poleward shifting the polar stratospheric jets, and a reduction in Arctic lower stratospheric ozone.

  8. Internally generated preactivation of single neurons in human medial frontal cortex predicts volition

    Science.gov (United States)

    Fried, Itzhak; Mukamel, Roy; Kreiman, Gabriel

    2011-01-01

    Understanding how self-initiated behavior is encoded by neuronal circuits in the human brain remains elusive. We recorded the activity of 1019 neurons while twelve subjects performed self-initiated finger movement. We report progressive neuronal recruitment over ~1500 ms before subjects report making the decision to move. We observed progressive increase or decrease in neuronal firing rate, particularly in the supplementary motor area (SMA), as the reported time of decision was approached. A population of 256 SMA neurons is sufficient to predict in single trials the impending decision to move with accuracy greater than 80% already 700 ms prior to subjects’ awareness. Furthermore, we predict, with a precision of a few hundred ms, the actual time point of this voluntary decision to move. We implement a computational model whereby volition emerges once a change in internally generated firing rate of neuronal assemblies crosses a threshold. PMID:21315264

  9. Generating mid-IR octave-spanning supercontinua and few-cycle pulses with solitons in phase-mismatched quadratic nonlinear crystals

    DEFF Research Database (Denmark)

    Bache, Morten; Guo, Hairun; Zhou, Binbin

    2013-01-01

    We discuss a novel method for generating octave-spanning supercontinua and few-cycle pulses in the important mid-IR wavelength range. The technique relies on strongly phase-mismatched cascaded second-harmonic generation (SHG) in mid-IR nonlinear frequency conversion crystals. Importantly we here...... of the promising crystals: in one case soliton pulse compression from 50 fs to 15 fs (1.5 cycles) at 3.0 μm is achieved, and at the same time a 3-cycle dispersive wave at 5.0 μm is formed that can be isolated using a long-pass filter. In another example we show that extremely broadband supercontinua can form...

  10. Generation of 3.5 W of diffraction-limited green light from SHG of a single tapered diode laser in a cascade of nonlinear crystals

    DEFF Research Database (Denmark)

    Hansen, Anders Kragh; Jensen, Ole Bjarlin; Sumpf, Bernd

    2014-01-01

    Many applications, e.g., within biomedicine stand to benefit greatly from the development of diode laser-based multi- Watt efficient compact green laser sources. The low power of existing diode lasers in the green area (about 100 mW) means that the most promising approach remains nonlinear...... frequency conversion of infrared tapered diode lasers. Here, we describe the generation of 3.5 W of diffraction-limited green light from SHG of a single tapered diode laser, itself yielding 10 W at 1063 nm. This SHG is performed in single pass through a cascade of two PPMgO:LN crystals with re...... power of 3.5 W corresponds to a power enhancement greater than 2 compared to SHG in each of the crystals individually and is the highest visible output power generated by frequency conversion of a single diode laser. Such laser sources provide the necessary pump power for biophotonics applications...

  11. Structural analysis of steam generator internals following feed water main steam line break: DLF approach

    International Nuclear Information System (INIS)

    Bhasin, Vivek; Kushwaha, H.S.; Mahajan, S.C.; Kakodkar, A.

    1993-01-01

    In order to evaluate the possible release of radioactivity in extreme events, some postulated accidents are analysed and studied during the design stage of Steam Generator (SG). Among the various accidents postulated, the most important are Feed Water Line Break (FWLB) and Main Steam Line Break (MSLB). This report concerns with dynamic structural analysis of SG internals following FWLB/MSLB. The pressure/drag-force time histories considered were corresponding to the conditions leading to the accident of maximum potential. The SG internals were analysed using two approaches of structural dynamics. In first approach simplified DLF method was adopted. This method yields an upper bound values of stresses and deflection. In the second approach time history analysis by Mode Superposition Technique was adopted. This approach gives more realistic results. The structure was qualified as per ASME B and PV Code SecIII NB. It was concluded that in all the components except perforated flow distribution plate, the stress values based on elastic analysis are within the limits specified by ASME Code. In case of perforated flow distribution plate during the MSLB transient the stress values based on elastic analysis are higher than the ASME Code limits. Therefore, its limit load analysis had to be done. Finally, the collapse pressure evaluated using limit load analysis was shown to be within the limits of ASME B and PV Code SecIII Nb. (author). 31 refs., 94 figs., 16 tabs

  12. Generation of Internal-Image Functional Aptamers of Okadaic Acid via Magnetic-Bead SELEX

    Directory of Open Access Journals (Sweden)

    Chao Lin

    2015-12-01

    Full Text Available Okadaic acid (OA is produced by Dinophysis and Prorocentrum dinoflagellates and primarily accumulates in bivalves, and this toxin has harmful effects on consumers and operators. In this work, we first report the use of aptamers as novel non-toxic probes capable of binding to a monoclonal antibody against OA (OA-mAb. Aptamers that mimic the OA toxin with high affinity and selectivity were generated by the magnetic bead-assisted systematic evolution of ligands by exponential enrichment (SELEX strategy. After 12 selection rounds, cloning, sequencing and enzyme-linked immunosorbent assay (ELISA analysis, four candidate aptamers (O24, O31, O39, O40 were selected that showed high affinity and specificity for OA-mAb. The affinity constants of O24, O31, O39 and O40 were 8.3 × 108 M−1, 1.47 × 109 M−1, 1.23 × 109 M−1 and 1.05 × 109 M−1, respectively. Indirect competitive ELISA was employed to determine the internal-image function of the aptamers. The results reveal that O31 has a similar competitive function as free OA toxin, whereas the other three aptamers did not bear the necessary internal-image function. Based on the derivation of the curvilinear equation for OA/O31, the equation that defined the relationship between the OA toxin content and O31 was Y = 2.185X − 1.78. The IC50 of O31 was 3.39 ng·mL−1, which was close to the value predicted by the OA ELISA (IC50 = 4.4 ng·mL−1; the IC10 was 0.33 ng·mL−1. The above data provides strong evidence that internal-image functional aptamers could be applicable as novel probes in a non-toxic assay.

  13. Biomass gasification for electricity generation with internal combustion engines. Process efficiency

    International Nuclear Information System (INIS)

    Lesme-Jaén, René; Garcia Faure, Luis; Recio Recio, Angel; Oliva Ruiz, Luis; Pajarín Rodríguez, Juan; Revilla Suarez, Dennis

    2015-01-01

    Biomass is a renewable source of energy worldwide increased prospects for its potential and its lower environmental impact compared to fossil fuels. By processes and energy conversion technologies it is possible to obtain fuels in solid, liquid and gaseous form from any biomass. The biomass gasification is the thermal conversion thereof into a gas, which can be used for electricity production with the use of internal combustion engines with a certain level of efficiency, which depends on the characteristics of biomass and engines used. In this work the evaluation of thermal and overall efficiency of the gasification in Integrated Forestry Enterprise of Santiago de Cuba, designed to generate electricity from waste from the forest industry is presented. Is a downdraft gasifier reactor, COMBO-80 model and engine manufacturing Hindu (diesel) model Leyland modified to work with producer gas. The evaluation was carried out for different loads (electric power generated) engine from experimental measurements of flow and composition of the gas supplied to the engine. The results show that the motor operates with a thermal efficiency in the range of 20-32% with an overall efficiency between 12-25%. (full text)

  14. Internally generated hippocampal sequences as a vantage point to probe future-oriented cognition.

    Science.gov (United States)

    Pezzulo, Giovanni; Kemere, Caleb; van der Meer, Matthijs A A

    2017-05-01

    Information processing in the rodent hippocampus is fundamentally shaped by internally generated sequences (IGSs), expressed during two different network states: theta sequences, which repeat and reset at the ∼8 Hz theta rhythm associated with active behavior, and punctate sharp wave-ripple (SWR) sequences associated with wakeful rest or slow-wave sleep. A potpourri of diverse functional roles has been proposed for these IGSs, resulting in a fragmented conceptual landscape. Here, we advance a unitary view of IGSs, proposing that they reflect an inferential process that samples a policy from the animal's generative model, supported by hippocampus-specific priors. The same inference affords different cognitive functions when the animal is in distinct dynamical modes, associated with specific functional networks. Theta sequences arise when inference is coupled to the animal's action-perception cycle, supporting online spatial decisions, predictive processing, and episode encoding. SWR sequences arise when the animal is decoupled from the action-perception cycle and may support offline cognitive processing, such as memory consolidation, the prospective simulation of spatial trajectories, and imagination. We discuss the empirical bases of this proposal in relation to rodent studies and highlight how the proposed computational principles can shed light on the mechanisms of future-oriented cognition in humans. © 2017 New York Academy of Sciences.

  15. International Conference on Crystal Growth (10th) Held in San Diego, California, on 16-21 August 1992

    Science.gov (United States)

    1993-07-14

    point defects in bulk ZnSe were subsequently [41 K. Terashima, M. Kawachi and M. Takena, I. Crystal investigated using positron annihilation technique [6...tIiguchi and Kohei Kodaira Department of Applied Chemistry, Faculty of Engineering Hokkaido University, Sapporo 060, Japan Rufile • TiO2 ) single crystals

  16. Investigation and design optimization of exhaust-based thermoelectric generator system for internal combustion engine

    International Nuclear Information System (INIS)

    Niu, Zhiqiang; Diao, Hai; Yu, Shuhai; Jiao, Kui; Du, Qing; Shu, Gequn

    2014-01-01

    Highlights: • A 3-D model for exhaust-based thermoelectric waste heat recovery is developed. • Various heat, mass and electric transfer characteristics are elucidated. • Channel size needs to be moderate to balance heat transfer and pressure drop. • Bafflers need to be placed at all locations near all TEG modules. • Baffler angle needs to be sufficiently large, especially for downstream locations. - Abstract: Thermoelectric generator (TEG) has attracted considerable attention for the waste heat recovery of internal combustion engine. In this study, a 3-D numerical model for engine exhaust-based thermoelectric generator (ETEG) system is developed. By considering the detailed geometry of thermoelectric generator (TEG) and exhaust channel, the various transport phenomena are investigated, and design optimization suggestions are given. It is found that the exhaust channel size needs to be moderate to balance the heat transfer to TEG modules and pressure drop along channel. Increasing the number of exhaust channels may improve the performance, however, since more space and TEG modules are needed, the system size and cost need to be considered as well. Although only placing bafflers at the channel inlet could increase the heat transfer coefficient for the whole channel, the near wall temperature downstream might decrease significantly, leading to performance degradation of the TEG modules downstream. To ensure effective utilization of hot exhaust gas, the baffler angle needs to be sufficiently large, especially for the downstream locations. Since larger baffler angles increase the pressure drop significantly, it is suggested that variable baffler angles, with the angle increasing along the flow direction, might be a middle course for balancing the heat transfer and pressure drop. A single ETEG design may not be suitable to all the engine operating conditions, and making the number of exhaust channels and baffler angle adjustable according to different engine

  17. Gasdynamic modeling and parametric study of mesoscale internal combustion swing engine/generator systems

    Science.gov (United States)

    Gu, Yongxian

    The demand of portable power generation systems for both domestic and military applications has driven the advances of mesoscale internal combustion engine systems. This dissertation was devoted to the gasdynamic modeling and parametric study of the mesoscale internal combustion swing engine/generator systems. First, the system-level thermodynamic modeling for the swing engine/generator systems has been developed. The system performance as well as the potentials of both two- and four-stroke swing engine systems has been investigated based on this model. Then through parameterc studies, the parameters that have significant impacts on the system performance have been identified, among which, the burn time and spark advance time are the critical factors related to combustion process. It is found that the shorter burn time leads to higher system efficiency and power output and the optimal spark advance time is about half of the burn time. Secondly, the turbulent combustion modeling based on levelset method (G-equation) has been implemented into the commercial software FLUENT. Thereafter, the turbulent flame propagation in a generic mesoscale combustion chamber and realistic swing engine chambers has been studied. It is found that, in mesoscale combustion engines, the burn time is dominated by the mean turbulent kinetic energy in the chamber. It is also shown that in a generic mesoscale combustion chamber, the burn time depends on the longest distance between the initial ignition kernel to its walls and by changing the ignition and injection locations, the burn time can be reduced by a factor of two. Furthermore, the studies of turbulent flame propagation in real swing engine chambers show that the combustion can be enhanced through in-chamber turbulence augmentation and with higher engine frequency, the burn time is shorter, which indicates that the in-chamber turbulence can be induced by the motion of moving components as well as the intake gas jet flow. The burn time

  18. Theoretical study and experimental scheme for the generation of a 1064-nm continuous variable entangled light source with quasi-phase-matching PPKTP crystal

    International Nuclear Information System (INIS)

    Liu, W.Y.; Bi, S.W.

    2011-01-01

    Beginning from Maxwell's equations, various factors required for the non-degenerate optical parametric amplifier (NOPA) to operate are considered step by step. Analytic expressions are obtained, generated from the experimental parameters and through the numerical simulation of the quantum-correlated spectrum between the signal and the idler modes from the NOPA operating below threshold. On this basis, an experimental program is designed for the generation of a 1064-nm continuous variable entanglement light source with a quasi-phase-matching periodical polarized KTiOPO 4 (PPKTP) crystal through a below-threshold optical parametric down-conversion process. This will play a crucial role in subsequent experiments.

  19. Fabrication of micro- and nanometre-scale polymer structures in liquid crystal devices for next generation photonics applications

    Science.gov (United States)

    Tartan, Chloe C.; Salter, Patrick S.; Booth, Martin J.; Morris, Stephen M.; Elston, Steve J.

    2016-09-01

    Direct Laser Writing (DLW) by two-photon photopolymerization (TPP) enables the fabrication of micron-scale polymeric structures in soft matter systems. The technique has implications in a broad range of optics and photonics; in particular fast-switching liquid crystal (LC) modes for the development of next generation display technologies. In this paper, we report two different methodologies using our TPP-based fabrication technique. Two explicit examples are provided of voltage-dependent LC director profiles that are inherently unstable, but which appear to be promising candidates for fast-switching photonics applications. In the first instance, 1 μm-thick periodic walls of polymer network are written into a planar aligned (parallel rubbed) nematic pi-cell device containing a nematic LC-monomer mixture. The structures are fabricated when the device is electrically driven into a fast-switching nematic LC state and aberrations induced by the device substrates are corrected for by virtue of the adaptive optics elements included within the DLW setup. Optical polarizing microscopy images taken post-fabrication reveal that polymer walls oriented perpendicular to the rubbing direction promote the stability of the so-called optically compensated bend mode upon removal of the externally applied field. In the second case, polymer walls are written in a nematic LC-optically adhesive glue mixture. A polymer- LCs-polymer-slices or `POLICRYPS' template is formed by immersing the device in acetone post-fabrication to remove any remaining non-crosslinked material. Injecting the resultant series of polymer microchannels ( 1 μm-thick) with a short-pitch, chiral nematic LC mixture leads to the spontaneous alignment of a fast-switching chiral nematic mode, where the helical axis lies parallel to the glass substrates. Optimal contrast between the bright and dark states of the uniform lying helix alignment is achieved when the structures are spaced at the order of the device thickness

  20. ARTIST: An International Project Investigating Aerosol Retention in a Ruptured Steam Generator

    International Nuclear Information System (INIS)

    Guentay, S.; Dehbi, A.; Suckow, D.; Birchley, J.

    2002-01-01

    Steam generator tube ruptures (SGTR) with a concurrent stuck open safety relief valve are counted among the risk dominant accident sequences because of the potential for radioactive products to bypass the containment. Owing to the absence of relevant empirical data and the complexity of the geometry and controlling processes, the aerosol removal in the steam generator (SG) tubes and in the secondary side is not well understood. Therefore, little or no credit is usually taken for aerosol retention due to natural processes in the various components of a SG. To help reduce the uncertainties associated with fission product release following an SGTR sequence, the Paul Scherrer Institut has initiated an international experimental project to be performed in the ARTIST (AeRosol Trapping In a Steam generaTor) facility in the time period from 2002 to 2007. The ARTIST test section is a scaled model of a real SG, and is comprised of a 264-tube bundle with a maximum height of 3.8 m, as well as one full-size droplet separator and one full-size steam dryer. The ARTIST facility is capable of producing soluble and insoluble aerosols and entrain them at sonic gas flow rates (up to 0.25 kg/s, thus matching comparable values predicted by the codes. In addition, aerosols can be generated at prototypical concentrations (up to 5 g/m 3 ) and sizes (0.2-5 mm AMMD). State of the art instrumentation is used (Low-pressure impactors, photometers, on-line particle sizer, online droplet sizer, etc.). The ARTIST project will simulate the flow and retention of aerosol-borne fission products in the SG, and provide a unique database to support safety assessments and analytical models. The project is foreseen in seven phases: 1) Aerosol retention in the tube under dry secondary side conditions, 2) Aerosol retention in the near field close to break under dry conditions, 3) Aerosol retention in the bundle far field under dry conditions, 4) Aerosol retention in the separator and dryer under dry

  1. The effects of ruthenium on the phase stability of fourth generation Ni-base single crystal superalloys

    International Nuclear Information System (INIS)

    Sato, Atsushi; Harada, Hiroshi; Yokokawa, Tadaharu; Murakumo, Takao; Koizumi, Yutaka; Kobayashi, Toshiharu; Imai, Hachiro

    2006-01-01

    The formation of topologically close-packed (TCP) phases in nickel-base single crystal superalloys causes considerable degradation of the mechanical properties. It has recently been found that platinum-group metals can be effective in controlling the precipitation of such phases, and this extent of precipitation control requires further investigation. This study compares Ru-containing and non-Ru-containing single crystal superalloys. Scanning electron microscopy microstructural observations showed that the rate of TCP phase precipitations decreased through Ru addition. Transmission electron microscopy microstructural observations showed that the P phase, one of the TCP phases, was eliminated through the addition of Ru. The occurrence of this phenomenon will be discussed

  2. Regulation of distributed generation. A European Policy Paper on the Integration of Distributed Generation in the Internal Electricity Market

    International Nuclear Information System (INIS)

    Van Sambeek, E.J.W.; Scheepers, M.J.J.

    2004-06-01

    In the SUSTELNET project criteria and guidelines have been developed that can create a level playing field in electricity markets between distributed generation (DG) and large scale power generation and will improve the network and market access of DG and electricity supply from renewable energy resources (RES). This report focuses on the European dimensions of DG regulation. The key findings of the SUSTELNET project are compared with the EU legislation, i.e. the current Electricity, Renewables and CHP Directives. Additional EU policy, regulation and initiatives are identified that can help Member States in developing future economically efficient and sustainable electricity supply systems

  3. Results from the OECD report on international projections of electricity generating costs

    International Nuclear Information System (INIS)

    Paffenbarger, J.A.; Bertel, E.

    1998-01-01

    The International Energy Agency and Nuclear Energy Agency of the OECD have periodically undertaken a joint study on electricity generating costs in OECD Member countries and selected non-Member countries. This paper presents key results from the 1998 update of this study. Experts from 19 countries drawn from electric utility companies and government provided data on capital costs, operating and maintenance costs, and fuel costs from which levelized electricity generating costs (US cents/kWh) for baseload power plants were estimated in each country using a common set of economic assumptions. Light water nuclear power plants, pulverized coal plants, and natural gas-fired combined cycle gas turbines were the principal options evaluated. five and 10% discount rates, 40-year operating lifetime, and 75% annual load factor were the base assumptions, with sensitivity analyses on operating lifetime and load factor. Fuel costs and fuel escalation were provided individually by country, with a sensitivity case to evaluate costs assuming no real fuel price escalation over plant lifetimes. Of the three principal fuel/technology options, none is predominantly the cheapest option for all economic assumptions. However, fossil-fueled options are generally estimated to be the least expensive option. The study confirms that gas-fired combined cycles have improved their economic performance in most countries in recent years and are strong competitors to nuclear and coal-fired plants. Eleven out of the 18 countries with two or more options show gas-fired plants to be the cheapest option at 10% discount rate. Coal remains a strong competitor to gas when lower discount rates are used. Nuclear is the least expensive at both 5 and 10% discount rate in only two countries. Generally, with gas prices above 5 US$/GJ, nuclear plants constructed at overnight capital costs below 1 650 $/kWe have the potential to be competitive only at lower discount rates

  4. Generation of high-field terahertz pulses in an HMQ-TMS organic crystal pumped by an ytterbium laser at 1030 nm.

    Science.gov (United States)

    Rovere, Andrea; Jeong, Young-Gyun; Piccoli, Riccardo; Lee, Seung-Heon; Lee, Seung-Chul; Kwon, O-Pil; Jazbinsek, Mojca; Morandotti, Roberto; Razzari, Luca

    2018-02-05

    We present the generation of high-peak-electric-field terahertz pulses via collinear optical rectification in a 2-(4-hydroxy-3-methoxystyryl)-1-methilquinolinium-2,4,6-trimethylbenzenesulfonate (HMQ-TMS) organic crystal. The crystal is pumped by an amplified ytterbium laser system, emitting 170-fs-long pulses centered at 1030 nm. A terahertz peak electric field greater than 200 kV/cm is obtained for 420 µJ of optical pump energy, with an energy conversion efficiency of 0.26% - about two orders of magnitude higher than in common inorganic crystals collinearly pumped by amplified femtosecond lasers. An open-aperture Z-scan measurement performed on an n-doped InGaAs thin film using such terahertz source shows a nonlinear increase in the terahertz transmission of about 2.2 times. Our findings demonstrate the potential of this terahertz generation scheme, based on ytterbium laser technology, as a simple and efficient alternative to the existing intense table-top terahertz sources. In particular, we show that it can be readily used to explore nonlinear effects at terahertz frequencies.

  5. Energetic mid-IR femtosecond pulse generation by self-defocusing soliton-induced dispersive waves in a bulk quadratic nonlinear crystal

    DEFF Research Database (Denmark)

    Zhou, Binbin; Guo, Hairun; Bache, Morten

    2015-01-01

    Generating energetic femtosecond mid-IR pulses is crucial for ultrafast spectroscopy, and currently relies on parametric processes that, while efficient, are also complex. Here we experimentally show a simple alternative that uses a single pump wavelength without any pump synchronization and with...... by using large-aperture crystals. The technique can readily be implemented with other crystals and laser wavelengths, and can therefore potentially replace current ultrafast frequency-conversion processes to the mid-IR....... and without critical phase-matching requirements. Pumping a bulk quadratic nonlinear crystal (unpoled LiNbO3 cut for noncritical phase-mismatched interaction) with sub-mJ near-IR 50-fs pulses, tunable and broadband (∼ 1,000 cm−1) mid-IR pulses around 3.0 μm are generated with excellent spatio-temporal pulse...... quality, having up to 10.5 μJ energy (6.3% conversion). The mid-IR pulses are dispersive waves phase-matched to near-IR self-defocusing solitons created by the induced self-defocusing cascaded nonlinearity. This process is filament-free and the input pulse energy can therefore be scaled arbitrarily...

  6. Theses of reports of the 30. International conference on physics of interaction of charged particles with crystals

    International Nuclear Information System (INIS)

    Tulinov, A.F.

    2000-01-01

    The collection contains theses of reports selected for presentation on the 30. Conference on Physics of Interaction of Charged Particles with Crystals. These Conference took place in Moscow, May 29-31, 2000. The problems of physics of orientation effects in crystals are discussed. The results of recent investigations of emission of electrons and positrons in solids are presented. The particular attention is given to processes of surface coating and nanostructure shaping by means of charged particles beams [ru

  7. On the generation and evolution of internal solitary waves in the southern Red Sea

    KAUST Repository

    Guo, Daquan; Zhan, Peng; Kartadikaria, Aditya R.; Akylas, Triantaphyllos; Hoteit, Ibrahim

    2015-01-01

    the relatively weak tidal velocity in this area and their generation in the central of the domain, Da Silva suggested three possible mechanisms behind the generation of the waves, namely Resonance and disintegration of interfacial tides, Generation of interfacial

  8. Multiple-octave spanning high-energy mid-IR supercontinuum generation in bulk quadratic nonlinear crystals

    DEFF Research Database (Denmark)

    Zhou, Binbin; Bache, Morten

    2016-01-01

    Bright and broadband coherent mid-IR radiation is important for exciting and probing molecular vibrations. Using cascaded nonlinearities in conventional quadratic nonlinear crystals like lithium niobate, self-defocusing near-IR solitons have been demonstrated that led to very broadband...

  9. Entangled photon pair generation by spontaneous parametric down-conversion in finite-length one-dimensional photonic crystals

    Czech Academy of Sciences Publication Activity Database

    Centini, M.; Peřina ml., Jan; Sciscione, L.; Sibilia, C.; Scalora, M.; Bloemer, M.J.; Bertolotti, M.

    2005-01-01

    Roč. 72, 03 (2005), 033806/1-033806/11 ISSN 1050-2947 R&D Projects: GA MŠk(CZ) OC P11.003 Institutional research plan: CEZ:AV0Z10100522 Keywords : photon pair * photonic crystals * spontaneous parametric down-conversion Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.997, year: 2005

  10. Converting existing Internal Combustion Generator (ICG) systems into HESs in standalone applications

    International Nuclear Information System (INIS)

    Perera, A.T.D.; Attalage, R.A.; Perera, K.K.C.K.; Dassanayake, V.P.C.

    2013-01-01

    Graphical abstract: - Highlights: • Obtained Pareto fronts of LEC, power supply reliability (PSR) and ICC/GHG emission. • Pareto surface was observed for smaller ICGs when considering LEC–PSR–GHG. • Shape of the LEC–PSR–ICC Pareto front gradually changes with ICG capacity. • Importance of multi-criterion decision-making after multi objective optimization. - Abstract: Expanding existing Internal Combustion Generator (ICG) systems by combining renewable energy sources is getting popular due to global concern on emission of green house gases (GHG) and increasing fossil fuel costs. Life cycle cost, initial capital cost (ICC), power supply reliability of the system, and GHG emission by ICG are factors to be considered in this process. Pareto front of Levelized Energy Cost (LEC)–Unmet Load Fraction (ULF)–GHG emission was taken in this study for four different expansion scenarios. Furthermore, Pareto front of ICC–LE–ULF was taken for three different expansion scenarios in order to analyze the impact of renewable energy integration. The results clearly depict that characteristics of the Pareto front varies with the scale of expansion and objectives taken for the optimization. A detailed analysis was conducted for a scale up problem with a 4 kVA ICG by using the Pareto fronts obtained

  11. Classical entropy generation analysis in cooled homogenous and functionally graded material slabs with variation of internal heat generation with temperature, and convective–radiative boundary conditions

    International Nuclear Information System (INIS)

    Torabi, Mohsen; Zhang, Kaili

    2014-01-01

    This article investigates the classical entropy generation in cooled slabs. Two types of materials are assumed for the slab: homogeneous material and FGM (functionally graded material). For the homogeneous material, the thermal conductivity is assumed to be a linear function of temperature, while for the FGM slab the thermal conductivity is modeled to vary in accordance with the rule of mixtures. The boundary conditions are assumed to be convective and radiative concurrently, and the internal heat generation of the slab is a linear function of temperature. Using the DTM (differential transformation method) and resultant temperature fields from the DTM, the local and total entropy generation rates within slabs are derived. The effects of physically applicable parameters such as the thermal conductivity parameter for the homogenous slab, β, the thermal conductivity parameter for the FGM slab, γ, gradient index, j, internal heat generation parameter, Q, Biot number at the right side, Nc 2 , conduction–radiation parameter, Nr 2 , dimensionless convection sink temperature, δ, and dimensionless radiation sink temperature, η, on the local and total entropy generation rates are illustrated and explained. The results demonstrate that considering temperature- or coordinate-dependent thermal conductivity and radiation heat transfer at both sides of the slab have great effects on the entropy generation. - Highlights: • The paper investigates entropy generation in a slab due to heat generation and convective–radiative boundary conditions. • Both homogeneous material and FGM (functionally graded material) were considered. • The calculations are carried out using the differential transformation method which is a well-tested analytical technique

  12. High-Efficiency Intracavity Continuous-Wave Green-Light Generation by Quasiphase Matching in a Bulk Periodically Poled MgO:LiNbO3 Crystal

    Directory of Open Access Journals (Sweden)

    Shaowei Chu

    2008-01-01

    Full Text Available 908 mW of green light at 532 nm were generated by intracavity quasiphase matching in a bulk periodically poled MgO:LiNbO3 (PPMgLN crystal. A maximum optical-to-optical conversion efficiency of 33.5% was obtained from a 0.5 mm thick, 10 mm long, and 5 mol% MgO:LiNbO3 crystal with an end-pump power of 2.7 W at 808 nm. The temperature bandwidth between the intracavity and single-pass frequency doubling was found to be different for the PPMgLN. Reliability and stability of the green laser were evaluated. It was found that for continuous operation of 100 hours, the output stability was better than 97.5% and no optical damage was observed.

  13. Architectures of intergenerational justice : Human dignity, international law, and duties to future generations

    NARCIS (Netherlands)

    Riley, Stephen

    2016-01-01

    This article draws attention to the constitutive requirements of intergenerational justice and exposes the limitations of regulative arguments based on international human rights law. Intergenerational justice demands constraining the regulative freedom of the international community, and it is

  14. Associations between subspecialty fellowship interest and knowledge of internal medicine: A hypothesis-generating study of internal medicine residents

    Science.gov (United States)

    2011-01-01

    Background Little is known about whether and how medical knowledge relates to interest in subspecialty fellowship training. The purpose of this study was to examine the relationships between residents' interest in subspecialty fellowship training and their knowledge of internal medicine (IM). Methods A questionnaire was emailed to 48 categorical postgraduate-year (PGY) two and three residents at a New York university-affiliated IM residency program in 2007 using the Survey Monkey online survey instrument. Overall and content area-specific percentile scores from the IM in-training examination (IM-ITE) for the same year was used to determine objective knowledge. Results Forty-five of 48 residents (response rate was 93.8%) completed the survey. Twenty-two (49%) were PG2 residents and 23(51%) were PGY3 residents. Sixty percent of respondents were male. Six (13%) residents were graduates of U.S. medical schools. Eight (18%) reported formal clinical training prior to starting internal medicine residency in the U.S. Of this latter group, 6 (75%) had training in IM and 6 (75) % reported a training length of 3 years or less. Thirty-seven of 45 (82%) residents had a subspecialty fellowship interest. Residents with a fellowship interest had a greater mean overall objective knowledge percentile score (56.44 vs. 31.67; p = 0.04) as well as greater mean percentile scores in all content areas of IM. The adjusted mean difference was statistically significant (p internal medicine residents. PMID:21281500

  15. Effect of the internal rib structure of the inclusions on the two-dimensional phononic crystal composed of periodic slotted tubes in air

    International Nuclear Information System (INIS)

    Yu Kunpeng; Chen Tianning; Wang Xiaopeng; Zhou Anan

    2012-01-01

    Using a finite element method based on the Bloch theorem, a new phononic crystal composed of periodic slotted tubes with internal rib structure in air is investigated. Two parallel plates with slit are introduced into the inclusion as the internal rib structure and its effect on band gaps is studied. The band structure and acoustic modes of the PC are calculated. Results show that the starting frequency of the first band gap is rather lower than that of slotted tubes without rib structure. The internal rib structure plays an important role in both the lower and upper edges of the first band gap. Some rib structural parameters are also studied for their effects on the first band gap. Results show that the first gap can be modulated widely by these parameters and the Helmholtz resonator theory can be used to explain the relationship between the band gap and the parameters.

  16. Microplasticity and dislocation mobility in copper-nickel single crystals evaluated from strain-amplitude-dependent internal friction. [CuNi

    Energy Technology Data Exchange (ETDEWEB)

    Nishino, Y.; Okada, Y.; Asano, S. (Dept. of Materials Science and Engineering, Nagoya Inst. of Tech. (Japan))

    1992-02-16

    Internal friction in copper-0.4 to 7.6 at% nickel single crystals is measured as a function of strain amplitude at various temperatures. Analysis of the data on the amplitude-dependent internal friction yields the relation of effective stress and microplastic strain of the order of 10{sup -9}. The stress-strain responses thus obtained exhibit that the microplastic flow stress increases more rapidly on alloying than the macroscopic yield stress. The mean dislocation velocity is also evaluated from the internal-friction data, which corresponds well to the etch-pit data. It is shown that the dislocation motion is impeded by friction due to dispersed solute atoms. (orig.).

  17. Associations between subspecialty fellowship interest and knowledge of internal medicine: A hypothesis-generating study of internal medicine residents

    Directory of Open Access Journals (Sweden)

    Haidet Paul

    2011-01-01

    Full Text Available Abstract Background Little is known about whether and how medical knowledge relates to interest in subspecialty fellowship training. The purpose of this study was to examine the relationships between residents' interest in subspecialty fellowship training and their knowledge of internal medicine (IM. Methods A questionnaire was emailed to 48 categorical postgraduate-year (PGY two and three residents at a New York university-affiliated IM residency program in 2007 using the Survey Monkey online survey instrument. Overall and content area-specific percentile scores from the IM in-training examination (IM-ITE for the same year was used to determine objective knowledge. Results Forty-five of 48 residents (response rate was 93.8% completed the survey. Twenty-two (49% were PG2 residents and 23(51% were PGY3 residents. Sixty percent of respondents were male. Six (13% residents were graduates of U.S. medical schools. Eight (18% reported formal clinical training prior to starting internal medicine residency in the U.S. Of this latter group, 6 (75% had training in IM and 6 (75 % reported a training length of 3 years or less. Thirty-seven of 45 (82% residents had a subspecialty fellowship interest. Residents with a fellowship interest had a greater mean overall objective knowledge percentile score (56.44 vs. 31.67; p = 0.04 as well as greater mean percentile scores in all content areas of IM. The adjusted mean difference was statistically significant (p Conclusions More than half of surveyed residents indicated interest in pursuing a subspecialty fellowship. Fellowship interest appears positively associated with general medical knowledge in this study population. Further work is needed to explore motivation and study patterns among internal medicine residents.

  18. Taking the Lead in Science Education: Forging Next-Generation Science Standards. International Science Benchmarking Report. Appendix

    Science.gov (United States)

    Achieve, Inc., 2010

    2010-01-01

    This appendix accompanies the report "Taking the Lead in Science Education: Forging Next-Generation Science Standards. International Science Benchmarking Report," a study conducted by Achieve to compare the science standards of 10 countries. This appendix includes the following: (1) PISA and TIMSS Assessment Rankings; (2) Courses and…

  19. Standard Setting for Next Generation TOEFL Academic Speaking Test (TAST): Reflections on the ETS Panel of International Teaching Assistant Developers

    Science.gov (United States)

    Papajohn, Dean

    2006-01-01

    While many institutions have utilized TOEFL scores for international admissions for many years, a speaking section has never before been a required part of TOEFL until the development of the iBT/Next Generation TOEFL. So institutions will need to determine how to set standards for the speaking section of TOEFL, also known as TOEFL Academic…

  20. Angle-resolved photoemission spectroscopy with 9-eV photon-energy pulses generated in a gas-filled hollow-core photonic crystal fiber

    OpenAIRE

    Bromberger, H.; Ermolov, A.; Belli, F.; Liu, H.; Calegari, F.; Chavez-Cervantes, M.; Li, M. T.; Lin, C. T.; Abdolvand, A.; Russell, P. St. J.; Cavalleri, A.; Travers, J. C.; Gierz, I.

    2015-01-01

    A recently developed source of ultraviolet radiation, based on optical soliton propagation in a gas-filled hollow-core photonic crystal fiber, is applied here to angle-resolved photoemission spectroscopy (ARPES). Near-infrared femtosecond pulses of only few {\\mu}J energy generate vacuum ultraviolet (VUV) radiation between 5.5 and 9 eV inside the gas-filled fiber. These pulses are used to measure the band structure of the topological insulator Bi2Se3 with a signal to noise ratio comparable to ...

  1. Performance of Generating Plant: Managing the Changes. Part 1: International availability data exchange for thermal generating plant

    Energy Technology Data Exchange (ETDEWEB)

    Stallard, G.S.; Deschaine, R. [Black and Veatch (United States)

    2008-05-15

    The WEC Committee on the Performance of Generating Plant (PGP) has been collecting and analysing power plant performance statistics worldwide for more than 30 years and has produced regular reports, which include examples of advanced techniques and methods for improving power plant performance through benchmarking. A series of reports from the various working groups was issued in 2008. This reference presents the results of Working Group 1 (WG1). WG1's primary focus is to analyse the best ways to measure, evaluate, and apply power plant performance and availability data to promote plant performance improvements worldwide. The paper explores the specific work activities of 2004-2007 to extend traditional analysis and benchmarking frameworks. It is divided into two major topics: Overview of current electric supply industry issues/trends; and, Technical Methods/Tools to evaluate performance in today's ESI.

  2. International Conference on Crystal Growth (10th) (ICCG-10) Held in San Diego, California on August 16 - 21, 1992

    Science.gov (United States)

    1992-08-21

    wcre subsequently [4] K. Terashima, M. Kawachi and M. Takena, J. Crystal investigated using positron annihilation technique [6]. It has Growth 102(1990... TiO2 and Rb2CO 3. The mixture was put in plati- (KDP), where d31 is smaller than of KTP, whereas d32 and num crucible and held for 24 hours at about 1000

  3. Acousto-optic control of internal acoustic reflection in tellurium dioxide crystal in case of strong elastic energy walkoff [Invited].

    Science.gov (United States)

    Voloshinov, Vitaly; Polikarpova, Nataliya; Ivanova, Polina; Khorkin, Vladimir

    2018-04-01

    Peculiar cases of acoustic wave propagation and reflection may be observed in strongly anisotropic acousto-optical crystals. A tellurium dioxide crystal serves as a prime example of such media, since it possesses record indexes of acoustic anisotropy. We studied one of the unusual scenarios of acoustic incidence and reflection from a free crystal-vacuum boundary in paratellurite. The directions of the acoustic waves in the (001) plane of the crystal were determined, and their basic characteristics were calculated. The carried-out acousto-optic experiment at the wavelength of light 532 nm and the acoustic frequency 73 MHz confirmed the theoretical predictions. The effects examined in the paper include the acoustic wave propagation with the record walkoff angle 74°. We also observed the incidence of the wave on the boundary at the angle exceeding 90°. Finally, we registered the close-to-back reflection of acoustic energy following the incidence. One of the stunning aspects is the distribution of energy between the incident and the back-reflected wave. The unusual features of the acoustic wave reflections pointed out in the paper are valuable for their possible applications in acousto-optic devices.

  4. Independent and arbitrary generation of spots in the 3D space domain with computer generated holograms written on a phase-only liquid crystal spatial light modulator

    International Nuclear Information System (INIS)

    Wang, Dong; Zhang, Jian; Xia, Yang; Wang, Hao

    2012-01-01

    An improved multiple independent iterative plane algorithm, based on a projection optimization idea, is proposed for the independent and arbitrary generation of one spot or multiple spots in a speckle-suppressed 3D work-area. Details of the mathematical expressions of the algorithm are given to theoretically show how it is improved for 3D spot generation. Both simulations and experiments are conducted to investigate the performance of the algorithm for independent and arbitrary 3D spot generation in several different cases. Simulation results agree well with experimental results, which validates the effectiveness of the algorithm proposed. Several additional experiments are demonstrated for fast and independent generation of four or more spots in the 3D space domain, which confirms the capabilities and practicalities of the algorithm further. (paper)

  5. A least squares method for a longitudinal fin with temperature dependent internal heat generation and thermal conductivity

    International Nuclear Information System (INIS)

    Aziz, A.; Bouaziz, M.N.

    2011-01-01

    Highlights: → Analytical solutions for a rectangular fin with temperature dependent heat generation and thermal conductivity. → Graphs give temperature distributions and fin efficiency. → Comparison of analytical and numerical solutions. → Method of least squares used for the analytical solutions. - Abstract: Approximate but highly accurate solutions for the temperature distribution, fin efficiency, and optimum fin parameter for a constant area longitudinal fin with temperature dependent internal heat generation and thermal conductivity are derived analytically. The method of least squares recently used by the authors is applied to treat the two nonlinearities, one associated with the temperature dependent internal heat generation and the other due to temperature dependent thermal conductivity. The solution is built from the classical solution for a fin with uniform internal heat generation and constant thermal conductivity. The results are presented graphically and compared with the direct numerical solutions. The analytical solutions retain their accuracy (within 1% of the numerical solution) even when there is a 60% increase in thermal conductivity and internal heat generation at the base temperature from their corresponding values at the sink temperature. The present solution is simple (involves hyperbolic functions only) compared with the fairly complex approximate solutions based on the homotopy perturbation method, variational iteration method, and the double series regular perturbation method and offers high accuracy. The simple analytical expressions for the temperature distribution, the fin efficiency and the optimum fin parameter are convenient for use by engineers dealing with the design and analysis of heat generating fins operating with a large temperature difference between the base and the environment.

  6. International, private-public, multi-mission, next-generation lunar laser retroreflectors

    Science.gov (United States)

    Dell'Agnello, Simone

    2017-04-01

    Since the 1970s Lunar Laser Ranging (LLR) to the Apollo/Lunokhod Cube Corner Retroreflector (CCR) arrays supplied some of the best tests of General Relativity (GR): possible changes in the gravitational constant, weak and strong equivalence principle, gravitational self-energy (PPN parameter beta), geodetic precession, inverse-square force-law [1][2]. LLR has also provided significant information on the composition of the deep interior of the Moon [3]. LLR physics analysis also allows for constraints on extensions of GR (like spacetime torsion [4]) and on new gravitational physics that may explain the gravitational universe without Dark Matter and Dark Energy (like Non-Minimally Coupled gravity [5]). LLR is the only Apollo/Lunokhod experiment still in operation. In the 1970s LLR arrays contributed a negligible fraction of the ranging error budget. Since the capabilities of ground stations of the International Laser Ranging Service (in particular APOLLO in USA) improved by more than two orders of magnitude, now, because of the lunar librations, current CCR arrays dominate the error. With the US/Italy project LLRRA21/MoonLIGHT (Lunar Laser Ranging Retroreflector Array for the 21st century/Moon Laser Instrumentation for General relativity High accuracy Tests) UMD (Univ. of Maryland) and INFN (Italian National Institute for Nuclear Physics) developed a new-generation LLR payload made by a single, large CCR (100 mm diameter), unaffected by the effect of librations, that will improve the LLR accuracy by a factor of ten to one hundred. The performance of this 'big CCR' is being characterized at the SCF_Lab test facility at INFN-LNF, Frascati, Italy [6]. INFN also developed INRRI (INstrument for landing-Roving laser Retroreflector Investigations), a microreflector payload for the lunar surface to be laser-ranged by orbiters [7]. This will further extend the physics and lunar science reach of LLR. INRRI can also provide positioning services on the far side (it is proposed

  7. FY 2008 Next Generation Safeguards Initiative International Safeguards Education and Training Pilot Progerams Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Dreicer, M; Anzelon, G; Essner, J; Dougan, A; Doyle, J; Boyer, B; Hypes, P; Sokova, E; Wehling, F

    2008-10-17

    Key component of the Next Generation Safeguards Initiative (NGSI) launched by the National Nuclear Security Administration is the development of human capital to meet present and future challenges to the safeguards regime. An effective university-level education in safeguards and related disciplines is an essential element in a layered strategy to rebuild the safeguards human resource capacity. Two pilot programs at university level, involving 44 students, were initiated and implemented in spring-summer 2008 and linked to hands-on internships at LANL or LLNL. During the internships, students worked on specific safeguards-related projects with a designated Laboratory Mentor to provide broader exposure to nuclear materials management and information analytical techniques. The Safeguards and Nuclear Material Management pilot program was a collaboration between the Texas A&M University (TAMU), Los Alamos National Laboratory (LANL) and Lawrence Livermore National Laboratory (LLNL). It included a 16-lecture course held during a summer internship program. The instructors for the course were from LANL together with TAMU faculty and LLNL experts. The LANL-based course was shared with the students spending their internship at LLNL via video conference. A week-long table-top (or hands-on) exercise on was also conducted at LANL. The student population was a mix of 28 students from a 12 universities participating in a variety of summer internship programs held at LANL and LLNL. A large portion of the students were TAMU students participating in the NGSI pilot. The International Nuclear Safeguards Policy and Information Analysis pilot program was implemented at the Monterey Institute for International Studies (MIIS) in cooperation with LLNL. It included a two-week intensive course consisting of 20 lectures and two exercises. MIIS, LLNL, and speakers from other U.S. national laboratories (LANL, BNL) delivered lectures for the audience of 16 students. The majority of students were

  8. FY 2008 Next Generation Safeguards Initiative International Safeguards Education and Training Pilot Programs Summary Report

    International Nuclear Information System (INIS)

    Dreicer, M.; Anzelon, G.; Essner, J.; Dougan, A.; Doyle, J.; Boyer, B.; Hypes, P.; Sokova, E.; Wehling, F.

    2008-01-01

    Key component of the Next Generation Safeguards Initiative (NGSI) launched by the National Nuclear Security Administration is the development of human capital to meet present and future challenges to the safeguards regime. An effective university-level education in safeguards and related disciplines is an essential element in a layered strategy to rebuild the safeguards human resource capacity. Two pilot programs at university level, involving 44 students, were initiated and implemented in spring-summer 2008 and linked to hands-on internships at LANL or LLNL. During the internships, students worked on specific safeguards-related projects with a designated Laboratory Mentor to provide broader exposure to nuclear materials management and information analytical techniques. The Safeguards and Nuclear Material Management pilot program was a collaboration between the Texas A and M University (TAMU), Los Alamos National Laboratory (LANL) and Lawrence Livermore National Laboratory (LLNL). It included a 16-lecture course held during a summer internship program. The instructors for the course were from LANL together with TAMU faculty and LLNL experts. The LANL-based course was shared with the students spending their internship at LLNL via video conference. A week-long table-top (or hands-on) exercise on was also conducted at LANL. The student population was a mix of 28 students from a 12 universities participating in a variety of summer internship programs held at LANL and LLNL. A large portion of the students were TAMU students participating in the NGSI pilot. The International Nuclear Safeguards Policy and Information Analysis pilot program was implemented at the Monterey Institute for International Studies (MIIS) in cooperation with LLNL. It included a two-week intensive course consisting of 20 lectures and two exercises. MIIS, LLNL, and speakers from other U.S. national laboratories (LANL, BNL) delivered lectures for the audience of 16 students. The majority of students

  9. Understanding internal backgrounds in NaI(Tl) crystals toward a 200 kg array for the KIMS-NaI experiment

    Energy Technology Data Exchange (ETDEWEB)

    Adhikari, P.; Adhikari, G.; Oh, S.Y. [Sejong University, Department of Physics, Seoul (Korea, Republic of); Choi, S.; Joo, H.W.; Kim, K.W.; Kim, S.K. [Seoul National University, Department of Physics and Astronomy, Seoul (Korea, Republic of); Ha, C.; Jeon, E.J.; Kang, W.G.; Kim, H.O.; Kim, N.Y.; Lee, H.S.; Lee, J.H.; Lee, M.H.; Leonard, D.S.; Li, J.; Olsen, S.L.; Park, H.K.; Park, K.S.; So, J.H.; Yoon, Y.S. [Institute for Basic Science, Center for Underground Physics, Daejeon (Korea, Republic of); Hahn, I.S. [Ewha Womans University, Department of Science Education, Seoul (Korea, Republic of); Kim, H.J. [Kyungpook National University, Department of Physics, Daegu (Korea, Republic of); Kim, Y.D. [Sejong University, Department of Physics, Seoul (Korea, Republic of); Institute for Basic Science, Center for Underground Physics, Daejeon (Korea, Republic of); Kim, Y.H. [Institute for Basic Science, Center for Underground Physics, Daejeon (Korea, Republic of); Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of); Park, H.S. [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2016-04-15

    The Korea Invisible Mass Search (KIMS) collaboration has developed low-background NaI(Tl) crystals that are suitable for the direct detection of WIMP dark matter. Building on experience accumulated during the KIMS-CsI programs, the KIMS-NaI experiment will consist of a 200 kg NaI(Tl) crystal array surrounded by layers of shielding structures and will be operated at the Yangyang underground laboratory. The goal is to provide an unambiguous test of the DAMA/LIBRA annual modulation signature. Measurements of six prototype crystals show progress in the reduction of internal contamination from radioisotopes. Based on our understanding of these measurements, we expect to achieve a background level in the final detector configuration that is less than 1 count/day/keV/kg for recoil energies around 2 keV. The annual modulation sensitivity for the KIMS-NaI experiment shows that an unambiguous 7σ test of the DAMA/LIBRA signature would be possible with a 600 kg year exposure with this system. (orig.)

  10. A Study on planning of promotion for international collaborative development of Generation IV Nuclear Energy Systems

    International Nuclear Information System (INIS)

    Hee, Chang Moon; Yang, M. S.; Ha, J. J.

    2006-06-01

    Korea has participated in the international collaboration programs for the development of future nuclear energy systems driven by the countries holding advanced nuclear technology and Korea and U. S. have cooperated in the INERI. This study is mainly at developing the plan for participation in the collaborative development of the Gen IV, searching the participation strategy for INERI and the INPRO, and the international cooperation in these programs. Contents and scope of the study for successful achievement are as follows; - Investigation and analysis of international and domestic trends related to advanced nuclear technologies - Development of the plan for collaborative development of the Gen IV and conducting the international cooperation activities - Support for the activities related to I-NERI between Korea and U. S. and conducting the international cooperation - International cooperation activities for the INPRO This study can be useful for planning the research plan and setting up of the strategy of integrating the results of the international collaboration and the domestic R and D results by combining the Gen IV and the domestic R and D in the field of future nuclear technology. Furthermore, this study can contribute to establishing the effective foundation and broadening the cooperation activities not only with the advanced countries for acquisition of the advanced technologies but also with the developing countries for the export of the domestic nuclear energy systems

  11. International Conference on Defects in Insulating Crystals Held at Parma, Italy on August 29th September 2nd, 1988

    Science.gov (United States)

    1988-09-01

    Divisione Fisica Applicata Centro Ricerche Energia Frascati, C.P. 65, 00044 Frascati, Italy F. De Matteis, A. Scacco, and F. Somma Dipartimento di...Various attractive potential applications, in solar energy conversion or in coherent optic technology for instance, are widely correlated to the optical...2) the solarization of LMA, which is the tendency for the crystals to color during optical excitation or exposure to ionizing radiation

  12. Discordant American College of Physicians and international rheumatology guidelines for gout management: consensus statement of the Gout, Hyperuricemia and Crystal-Associated Disease Network (G-CAN).

    Science.gov (United States)

    Dalbeth, Nicola; Bardin, Thomas; Doherty, Michael; Lioté, Frédéric; Richette, Pascal; Saag, Kenneth G; So, Alexander K; Stamp, Lisa K; Choi, Hyon K; Terkeltaub, Robert

    2017-09-01

    In November 2016, the American College of Physicians (ACP) published a clinical practice guideline on the management of acute and recurrent gout. This guideline differs substantially from the latest guidelines generated by the American College of Rheumatology (ACR), European League Against Rheumatism (EULAR) and 3e (Evidence, Expertise, Exchange) Initiative, despite reviewing largely the same body of evidence. The Gout, Hyperuricemia and Crystal-Associated Disease Network (G-CAN) convened an expert panel to review the methodology and conclusions of these four sets of guidelines and examine possible reasons for discordance between them. The G-CAN position, presented here, is that the fundamental pathophysiological knowledge underlying gout care, and evidence from clinical experience and clinical trials, supports a treat-to-target approach for gout aimed at lowering serum urate levels to below the saturation threshold at which monosodium urate crystals form. This practice, which is truly evidence-based and promotes the steady reduction in tissue urate crystal deposits, is promoted by the ACR, EULAR and 3e Initiative recommendations. By contrast, the ACP does not provide a clear recommendation for urate-lowering therapy (ULT) for patients with frequent, recurrent flares or those with tophi, nor does it recommend monitoring serum urate levels of patients prescribed ULT. Results from emerging clinical trials that have gout symptoms as the primary end point are expected to resolve this debate for all clinicians in the near term future.

  13. DIRC dreams: research directions for the next generation of internally reflected imaging counters

    International Nuclear Information System (INIS)

    Ratcliff, Blair N.; Spanier, Stefan

    1999-01-01

    Some conceptual design features of the total internally reflecting, imaging Cherenkov counter (DIRC) are described. Limits of the DIRC approach to particle identification, and a few features of alternative DIRC designs, are briefly explored

  14. DIRC Dreams Redux: Research Directions for the Next Generation of Internally Reflected Imaging Counters

    Energy Technology Data Exchange (ETDEWEB)

    Ratcliff, Blair N

    2001-09-18

    Some general conceptual design features of total internally reflecting, imaging Cherenkov counters (DIRCs) are described. Limits of the DIRC approach to particle identification and a few features of alternative DIRC designs are briefly explored.

  15. The generation and gender shifts in medicine: an exploratory survey of internal medicine physicians

    Directory of Open Access Journals (Sweden)

    Lemaire Jane

    2006-05-01

    Full Text Available Abstract Background Two striking demographic shifts evident in today's workforce are also apparent in the medical profession. One is the entry of a new generation of physicians, Gen Xers, and the other is the influx of women. Both shifts are argued to have significant implications for recruitment and retention because of assumptions regarding the younger generation's and women's attitudes towards work and patient care. This paper explores two questions regarding the generations: (1 How do Baby Boomer and Generation X physicians perceive the generation shift in work attitudes and behaviours? and (2 Do Baby Boomer and Generation X physicians differ significantly in their work hours and work attitudes regarding patient care and life balance? Gen Xers include those born between 1965 and 1980; Baby Boomers are those born between 1945 and 1964. We also ask: Do female and male Generation X physicians differ significantly in their work hours and work attitudes regarding patient care and life balance? Methods We conducted exploratory interviews with 54 physicians and residents from the Department of Medicine (response rate 91% and asked about their perceptions regarding the generation and gender shifts in medicine. We limit the analyses to interview responses of 34 Baby Boomers and 18 Generation Xers. We also sent questionnaires to Department members (response rate 66%, and this analysis is limited to 87 Baby Boomers' and 65 Generation Xers' responses. Results The qualitative interview data suggest significant generation and gender shifts in physicians' attitudes. Baby Boomers generally view Gen Xer physicians as less committed to their medical careers. The quantitative questionnaire data suggest that there are few significant differences in the generations' and genders' reports of work-life balance, work hours and attitudes towards patient care. Conclusion A combined qualitative and quantitative approach to the generation shift and gender shift in

  16. Technical evaluation of RETS-required reports for Crystal River Nuclear Generating Plant, Unit 3, for 1983

    International Nuclear Information System (INIS)

    Magleby, E.H.; Young, T.E.

    1985-01-01

    A review was performed on the reports required by Federal regulations and the plant-specific Radiological Effluent Technical Specifications (RETS) for operations conducted at Florida Power Corporation's Crystal River Nuclear Plant, Unit 3, during 1983. The three periodic reports reviewed were (1) the Effluent and Waste Disposal Semiannual Report, January 1-June 30, 1983, (2) the Effluent and Waste Disposal Semiannual Report, July 1-December 31, 1983, and (3) the Annual Environmental Operating Report, Radiological, 1983. The principal review guidelines were the plant's specific RETS and NRC guidance given in NUREG-0133, ''Preparation of Radiological Effluent Technical Specifications for Nuclear Power Plants.'' The Licensee's submitted reports were found to be reasonably complete and consistent with the review guidelines

  17. Developing the Next Generation of International Safeguards and Nonproliferation Experts: Highlights of Select Activities at the National Laboratories

    Energy Technology Data Exchange (ETDEWEB)

    Reed, J; Mathews, C; Kirk, B; Lynch, P; Doyle, J; Meek, E; Pepper, S; Metcalf, R

    2010-03-31

    With many safeguards experts in the United States at or near retirement age, and with the growing and evolving mission of international safeguards, attracting and educating a new generation of safeguards experts is an important element of maintaining a credible and capable international safeguards system. The United States National Laboratories, with their rich experience in addressing the technical and policy challenges of international safeguards, are an important resource for attracting, educating, and training future safeguards experts. This presentation highlights some of the safeguards education and professional development activities underway at the National Laboratories. These include university outreach, summer courses, internships, mid-career transition, knowledge retention, and other projects. The presentation concludes with thoughts on the challenge of interdisciplinary education and the recruitment of individuals with the right balance of skills and backgrounds are recruited to meet tomorrow's needs.

  18. Calorimetric features of release of plastic deformation induced internal stresses, and approach to equilibrium state on annealing of crystals and glasses

    Energy Technology Data Exchange (ETDEWEB)

    Johari, G.P., E-mail: joharig@mcmaster.ca

    2014-04-01

    Highlights: • Stress release in a glass occurs at a faster rate than structural relaxation. • Plastically-deformed glass would show two exothermic minima, and no glass transition. • Enthalpy matching procedure would yield an inaccurate fictive temperature. • Complex heat capacity may distinguish plastically-deformed from quench-formed glass. - Abstract: Plastic deformation of crystals and glasses produces internal strains (stresses), which change their energy and other thermodynamic properties. On annealing, these stresses decrease at a rate faster than the structure relaxes toward the equilibrium state. Mechanism of such relaxations in crystals differs from that in glasses and it also differs for glasses of different types. In all cases, the energy related properties decrease with time isothermally and on heating, resembling the structure relaxation of a stress-free glass. We consider these features and argue that kinetics of enthalpy loss with time yields the rate constants of the stress release and of the structure change, and not the viscosity determining α-relaxation time. Since thermal cycling does not recover the enthalpy from internal stresses, a glass with stresses has neither a glass-softening temperature, T{sub g}, nor a fictive temperature, T{sub f}. Plastic deformation would not rejuvenate a physically aged glass to the properties of its un-aged state. The Prigogine–Defay ratio can be extended to all T{sub f}s, and used to investigate the effect of distribution of relaxation times on its value, but it can not be defined for an internally stressed glass. After discussing the effects of annealing on the heat capacity and DSC scans, we conclude that on slow heating, glass with deformation-induced stresses would show two exothermic minima, and normal glass would show only one such minimum. Temperature-modulated scanning calorimetry would also distinguish an internally stressed glass from an equally high-enthalpy, stress-free glass. Enthalpy

  19. First generation of Spanish authors to disseminate hospitality and tourism research internationally

    Directory of Open Access Journals (Sweden)

    Jesús Manuel López-Bonilla

    2017-09-01

    Full Text Available Spanish researchers have shown an increasing interest in the bibliometric analysis of tourism research. However, as of yet a sufficiently comprehensive authorship analysis on Spanish tourism research has not been performed. This study analyses the international scientific output of scholars in Spain. The search was performed using the Scopus database from 2002 to 2013. It established a ranking of 79 Spanish authors who have published six or more papers in international scientific journals. The average number of Spanish co-authors per paper is high with respect to international authors. Also, a clear gender inequality is observed, with male authors dominating. The areas of Economy and Marketing stand out for the total number of papers produced in them, as do the universities of Islas Baleares and Alicante for their output.

  20. Modeling Electrostatic Fields Generated by Internal Charging of Materials in Space Radiation Environments

    Science.gov (United States)

    Minow, Joseph I.

    2011-01-01

    Internal charging is a risk to spacecraft in energetic electron environments. DICTAT, NU MIT computational codes are the most widely used engineering tools for evaluating internal charging of insulator materials exposed to these environments. Engineering tools are designed for rapid evaluation of ESD threats, but there is a need for more physics based models for investigating the science of materials interactions with energetic electron environments. Current tools are limited by the physics included in the models and ease of user implementation .... additional development work is needed to improve models.

  1. Angular non-critical phase-matching second-harmonic-generation characteristics of RECOB (RE = Tm, Y, Gd, Sm, Nd and La) crystals.

    Science.gov (United States)

    Liu, Yanqing; Wang, Zhengping; Yu, Fapeng; Qi, Hongwei; Yang, Xiuqin; Yu, Xiaoqiang; Zhao, Xian; Xu, Xinguang

    2017-05-15

    For the first time, the angular non-critical phase-matching (A-NCPM) second-harmonic-generation (SHG) characteristics of a family of monoclinic oxoborate crystals, RECa 4 O(BO 3 ) 3 (RECOB, RE = Tm, Y, Gd, Sm, Nd and La), were comprehensively investigated. For all of the realizable A-NCPM SHG styles, the feature parameters including PM wavelength, angular, wavelength and temperature acceptance bandwidths, have been derived from the theory and verified by the experiments. We discovered that the closer the ion radius between RE 3+ and Ca 2+ , the smaller the birefringence, and the better the A-NCPM SHG properties. As a result, for the Type-I SHG on Y-axis which has the largest effective nonlinear optical coefficient (d eff ) among the three realizable A-NCPM styles, NdCOB crystal presents the longest PM wavelength (927 nm), the largest angular acceptance bandwidth (Δθ⋅l 1/2 = 84.3 mrad·cm 1/2 , Δϕ⋅l 1/2 = 58.8 mrad·cm 1/2 ), and the broadest wavelength acceptance bandwidth (8.7 nm). This discovery will contribute to the design of new NCPM materials, at the same time the parameter formula will be helpful for the theoretical prediction of NCPM performance.

  2. An Internationally Comparative Study of Immigration and Adolescent Emotional and Behavioral Problems:Effects of Generation and Gender

    DEFF Research Database (Denmark)

    Stevens, Gonneke W J M; Walsh, Sophie D; Huijts, Tim

    2015-01-01

    psychosomatic symptoms than native adolescents. Effect sizes varied considerable for the different outcomes, and similar effects were found for first- and second-generation immigrant adolescents. Differences in these indicators of emotional and behavioral problems between immigrant and native adolescents did......PURPOSE: Although the potential consequences of immigration for adolescent problem behaviors have been addressed in many former studies, internationally comparative research is scarce. This study investigated the impact of immigration on four indicators of adolescents' emotional and behavioral...... not vary significantly with the receiving country. With two exceptions, effects of immigrant status were similar for boys and girls. Although no differences in psychosomatic symptoms were found between first-generation immigrant and native girls, first-generation immigrant boys reported less psychosomatic...

  3. Self-organized TiO2 nanotubular arrays for photoelectrochemical hydrogen generation: effect of crystallization and defect structures

    International Nuclear Information System (INIS)

    Mahajan, V K; Misra, M; Raja, K S; Mohapatra, S K

    2008-01-01

    The effect of crystallization and surface chemistry of nanotubular titanium dioxide (TiO 2 ) in connection with the photoelectrochemical process is reported in this investigation. TiO 2 nanotubular arrays were synthesized by a simple anodization process in an acidified fluoride electrolyte at room temperature. The TiO 2 nanotubes were amorphous in as-anodized condition; their transformation to crystalline phases was a function of annealing temperature and gaseous environment. The anatase phase was observed predominantly after annealing in non-oxidizing atmospheres, whereas annealing in an oxygen environment showed a mixture of anatase and rutile phases. X-ray photoelectron spectroscopy was used to determine the chemical environment of the surface, which revealed the presence of phosphate, oxygen vacancies and pentacoordinated Ti in hydrogen annealed samples. Diffuse reflectance photospectrometry of non-oxygen annealed samples showed long absorption tails extending in the visible region. The photoelectrochemical response of the TiO 2 nanotubes annealed in different conditions was investigated. Photoelectrochemical performance under simulated solar light was improved by annealing the nanotubular TiO 2 samples in non-oxidizing environment

  4. International ITER fusion energy organization. Paving the way to power generation from nuclear fusion

    International Nuclear Information System (INIS)

    Preuschen-Liebenstein, R. von

    2006-01-01

    ITER (Latin: the way) is the acronym of a new international large research facility gradually taking shape after the meeting of Gorbachev and Reagan in Reykjavik in 1985. Under the auspices of the IAEA, worldwide scientific and industrial cooperation with 'home teams' of each of the ITER partners began at that time which were commissioned to accumulate the knowledge and the technology of nuclear fusion in the participating countries. At the end of the preparation and decisionmaking process, the design draft of the ITER reactor was elaborated in international cooperation as the basis of the ITER Convention. After lengthy negotiations among the international ITER partners, a European site for the ITER organization and its reactor was found at Cadarache, France. As the first ITER member, Europe now initiated worldwide cooperation in research and development, seeking to demonstrate the technical and scientific feasibility of tapping fusion power for peaceful purposes. The Council of the European Union (competitiveness), at its meeting on September 25, 2006, decided to sign the ITER Convention about the establishment of the International ITER Fusion Energy Organization ('ITER Organization') and about the mutual obligation to make the necessary contributions towards the construction of ITER. (orig.)

  5. GENERATION OF KNOWLEDGE INTO CONCEPTION OF CULTURAL PRAGMATIZM AND ITS INFLUENCE ON INTERNATIONAL BUSINESS

    Directory of Open Access Journals (Sweden)

    Teimurz SHENGELIA

    2016-08-01

    Full Text Available To study the phenomenon of cultural difference and diversity and to establish its influence on efficiency of the international business is the most important problem. The present problem occupies a wide space in the theory and practice of management of the international companies. Within last periods many scientific studies were dedicated to research of the present problem. Despite this, the theories existing in this sphere, as a rule, are limited with specifying the influence of cultural determinants on the international business. Along with this, the present problem has many aspects and to understand how the managers turn the process of transformation of the knowledge on culture into a competitive advantage of a company, it is necessary to establish new approaches in the existing theory of management. The present article, based on the analysis and generalization of the theoretical approaches existing in the field of influence of the cultural relations on the international business, substantiates the need for passing from the statistical measurement of culture to dynamic construction – “perception prism” of the reality, which is used by its carrier to form the fundamentals of unified codification of knowledge. The paper presents a new conceptual model, gives possibility to assess theoretical relevance and practical application of the suggested approaches.

  6. Glass and crystallization like transitions at low temperature in Zr-Cu based glasses by internal friction measurements

    Directory of Open Access Journals (Sweden)

    Aboki A.T.

    2011-05-01

    Full Text Available Low temperature β internal friction peak evolution upon thermal cycles shows two peculiar peaks similar to high temperature internal friction peak. The modulus softening associated to these peaks suggest a phase transformation phenomenon and the relaxation time τo in order of 10-23–10-35s, close to that observed in grains boundary sliding are due to interface motions in the amorphous structure under combined thermal and mechanical energies.

  7. Layout of an internally heated gas generator for the steam gasification of coal

    International Nuclear Information System (INIS)

    Feistel, P.P.; Duerrfeld, R.; Heck, K.H. van; Juentgen, H.

    1975-01-01

    Industrial-scale steam gasification of coal using heat from high temperature reactors requires research and development on allothermal gas generators. Bergbau-Forschung GmbH, Essen, does theoretical and experimental work in this field. The experiments deal with reaction kinetics, heat transfer and material tests. Their significance for the layout of a full-scale gas generator is shown. Including material specifications, the feasibility of a gasifier, characterized by a fluid bed volume of 318 m 3 and a heat transferring area of 4000 m 2 , results. The data, now available, are used to determine the gasification throughput from the heat balance, i.e. the equality of heat consumed and heat transferred. Throughputs of about 50 t/hr of coal are possible for a single gas generator, the helium outlet temperature of the HTR being 950 0 C/ Bergbau-Forschung has commissioned a medium-scale pilot plant (200 kg/hr). (Auth.)

  8. Angle-resolved photoemission spectroscopy with 9-eV photon-energy pulses generated in a gas-filled hollow-core photonic crystal fiber

    Science.gov (United States)

    Bromberger, H.; Ermolov, A.; Belli, F.; Liu, H.; Calegari, F.; Chávez-Cervantes, M.; Li, M. T.; Lin, C. T.; Abdolvand, A.; Russell, P. St. J.; Cavalleri, A.; Travers, J. C.; Gierz, I.

    2015-08-01

    A recently developed source of ultraviolet radiation, based on optical soliton propagation in a gas-filled hollow-core photonic crystal fiber, is applied here to angle-resolved photoemission spectroscopy (ARPES). Near-infrared femtosecond pulses of only few μJ energy generate vacuum ultraviolet radiation between 5.5 and 9 eV inside the gas-filled fiber. These pulses are used to measure the band structure of the topological insulator Bi2Se3 with a signal to noise ratio comparable to that obtained with high order harmonics from a gas jet. The two-order-of-magnitude gain in efficiency promises time-resolved ARPES measurements at repetition rates of hundreds of kHz or even MHz, with photon energies that cover the first Brillouin zone of most materials.

  9. Angle-resolved photoemission spectroscopy with 9-eV photon-energy pulses generated in a gas-filled hollow-core photonic crystal fiber

    International Nuclear Information System (INIS)

    Bromberger, H.; Liu, H.; Chávez-Cervantes, M.; Gierz, I.; Ermolov, A.; Belli, F.; Abdolvand, A.; Russell, P. St. J.; Travers, J. C.; Calegari, F.; Li, M. T.; Lin, C. T.; Cavalleri, A.

    2015-01-01

    A recently developed source of ultraviolet radiation, based on optical soliton propagation in a gas-filled hollow-core photonic crystal fiber, is applied here to angle-resolved photoemission spectroscopy (ARPES). Near-infrared femtosecond pulses of only few μJ energy generate vacuum ultraviolet radiation between 5.5 and 9 eV inside the gas-filled fiber. These pulses are used to measure the band structure of the topological insulator Bi 2 Se 3 with a signal to noise ratio comparable to that obtained with high order harmonics from a gas jet. The two-order-of-magnitude gain in efficiency promises time-resolved ARPES measurements at repetition rates of hundreds of kHz or even MHz, with photon energies that cover the first Brillouin zone of most materials

  10. Angle-resolved photoemission spectroscopy with 9-eV photon-energy pulses generated in a gas-filled hollow-core photonic crystal fiber

    Energy Technology Data Exchange (ETDEWEB)

    Bromberger, H., E-mail: Hubertus.Bromberger@mpsd.mpg.de; Liu, H.; Chávez-Cervantes, M.; Gierz, I. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Ermolov, A.; Belli, F.; Abdolvand, A.; Russell, P. St. J.; Travers, J. C. [Max Planck Institute for the Science of Light, Günther-Scharowsky-Str. 1, 91058 Erlangen (Germany); Calegari, F. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Institute for Photonics and Nanotechnologies, IFN-CNR, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy); Li, M. T.; Lin, C. T. [Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart (Germany); Cavalleri, A. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Clarendon Laboratory, Department of Physics, University of Oxford, Parks Rd. Oxford OX1 3PU (United Kingdom)

    2015-08-31

    A recently developed source of ultraviolet radiation, based on optical soliton propagation in a gas-filled hollow-core photonic crystal fiber, is applied here to angle-resolved photoemission spectroscopy (ARPES). Near-infrared femtosecond pulses of only few μJ energy generate vacuum ultraviolet radiation between 5.5 and 9 eV inside the gas-filled fiber. These pulses are used to measure the band structure of the topological insulator Bi{sub 2}Se{sub 3} with a signal to noise ratio comparable to that obtained with high order harmonics from a gas jet. The two-order-of-magnitude gain in efficiency promises time-resolved ARPES measurements at repetition rates of hundreds of kHz or even MHz, with photon energies that cover the first Brillouin zone of most materials.

  11. High-energy azimuthally polarized laser beam generation from an actively Q-switched Nd:YAG laser with c-cut YVO4 crystal

    Science.gov (United States)

    Guo, Jing; Zhang, Baofu; Jiao, Zhongxing; He, Guangyuan; Wang, Biao

    2018-05-01

    A high-energy, azimuthally polarized (AP) and actively Q-switched Nd:YAG laser is demonstrated. The thermal bipolar lensing effect in the Nd:YAG laser rod is used as a polarization discriminator, and a c-cut YVO4 crystal is inserted into the laser cavity to increase the mode-selecting ability of the cavity for AP mode. The laser generated AP pulses with maximum pulse energy as high as 4.2 mJ. To the best of our knowledge, this is the highest pulse energy obtained from an actively Q-switched AP laser. The pulse energy remained higher than 1 mJ over a wide range of repetition rates from 5 kHz to 25 kHz.

  12. Catalyzed hydrogenation of nitrogen and ethylene on metal (Fe, Pt) single crystal surfaces and effects of coadsorption: A sum frequency generation vibrational spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Westerberg, Staffan Per Gustav [Univ. of California, Berkeley, CA (United States)

    2004-01-01

    High-pressure catalytic reactions and associated processes, such as adsorption have been studied on a molecular level on single crystal surfaces. Sum Frequency Generation (SFG) vibrational spectroscopy together with Auger Electron Spectroscopy (AES), Temperature Programmed Desorption (TPD) and Gas Chromatography (GC) were used to investigate the nature of species on catalytic surfaces and to measure the catalytic reaction rates. Special attention has been directed at studying high-pressure reactions and in particular, ammonia synthesis in order to identify reaction intermediates and the influence of adsorbates on the surface during reaction conditions. The adsorption of gases N2, H2, O2 and NH3 that play a role in ammonia synthesis have been studied on the Fe(111) crystal surface by sum frequency generation vibrational spectroscopy using an integrated Ultra-High Vacuum (UHV)/high-pressure system. SFG spectra are presented for the dissociation intermediates, NH2 (~3325 cm-1) and NH (~3235 cm-1) under high pressure of ammonia (200 Torr) on the clean Fe(111) surface. Addition of 0.5 Torr of oxygen to 200 Torr of ammonia does not significantly change the bonding of dissociation intermediates to the surface. However, it leads to a phase change of nearly 180° between the resonant and non-resonant second order non-linear susceptibility of the surface, demonstrated by the reversal of the SFG spectral features. Heating the surface in the presence of 200 Torr ammonia and 0.5 Torr oxygen reduces the oxygen coverage, which can be seen from the SFG spectra as another relative phase change of 180°. The reduction of the oxide is also supported by Auger electron spectroscopy. The result suggests that the phase change of the spectral features could serve as a sensitive indicator of the chemical environment of the adsorbates.

  13. Applications of Generative Learning for the Survey of International Economics Course

    Science.gov (United States)

    Sharp, David C.; Knowlton, Dave S.; Weiss, Renee E.

    2005-01-01

    Generative learning provides students with opportunities to organize course content, integrate new content with students' current knowledge, and elaborate on course content by making connections to real-world events. These opportunities promote less reliance on professors' lectures and simultaneously create more self-reliance among students. The…

  14. Proceedings of the international workshop on next-generation linear colliders

    International Nuclear Information System (INIS)

    Riordan, M.

    1988-12-01

    This report contains papers on the next-generation of linear colliders. The particular areas of discussion are: parameters; beam dynamics and wakefields; damping rings and sources; rf power sources; accelerator structures; instrumentation; final focus; and review of beam-beam interaction

  15. Influence of the external and internal parameters on the characteristics of generator PV

    Science.gov (United States)

    Zouli, Mounir; Ghoudelbourk, Sihem; Ouari, Ahmed; Dib, Djallel

    2017-02-01

    The growing demand for electric power and inevitable future depletion of conventional sources require major research on the alternative sources, like renewable energies. Among which, solar energy is the most largely used because of its many applications. And as Algeria comprises an exceptional solar layer thanks to its large surfaces, therefore it represents an important source of photovoltaic energy. The objective of this work is to be ensured that the energy produced by the photovoltaic plant supplies the electrical distribution network. The configuration of this system comprises a photovoltaic generator, connected to a chopper booster. For an optimal operation of the system, one must connect in cascades partial generators each one connected to a chopper booster adapted by an order MPPT by the method of Disturbance and Observation (P&O) to ensure the operation of their maximum powers whatever the climatic conditions, and also allows to raise the output voltage of these photovoltaic generators. The adaptation between the photovoltaic generator and the load was carried out with the help of converter DC/DC.

  16. Proceedings of the international workshop on next-generation linear colliders

    Energy Technology Data Exchange (ETDEWEB)

    Riordan, M. (ed.)

    1988-12-01

    This report contains papers on the next-generation of linear colliders. The particular areas of discussion are: parameters; beam dynamics and wakefields; damping rings and sources; rf power sources; accelerator structures; instrumentation; final focus; and review of beam-beam interaction.

  17. Effects of the composition and crystal structure of zinc-nickel alloy deposits on the internal strain

    Energy Technology Data Exchange (ETDEWEB)

    Tsuru, Y.; Tanaka, M. [Kyushu Inst. of Technology, Kitakyushu (Japan). Faculty of Engineering

    1996-02-05

    An average internal strain in the electrodeposited Zn-Ni alloy films was in-situ measured using the resistance wire type strain gauge setup on the reverse side of the copper substrate. The Ni content of the Zn-Ni alloy coatings utilized for the steel frame of automobiles and for the plastic coated steel sheets is around at 15% and the dominant structure is the {gamma}-phase. Such Zn-Ni alloy coatings are favorable for the protection of steel against corrosion. The internal stress in these deposits is always compressive during electroplating. However, upon turning off the current, the internal stress sharply changes from compressive to tensile. The tensile stress seems to simultaneously result in many cracks on the surface of the deposits. In this study, a resistance wire type strain gauge meter was used for successive measurement of the internal strain in the deposits during electroplating and solid-state stripping voltammetry was applied for the anodic dissolution of the deposits. And the effects concerning the partial electroleaching of Zn from the deposits on the internal strain in the deposits under periodic reverse plating. 15 refs., 8 figs., 3 tabs.

  18. Life Science on the International Space Station Using the Next Generation of Cargo Vehicles

    Science.gov (United States)

    Robinson, J. A.; Phillion, J. P.; Hart, A. T.; Comella, J.; Edeen, M.; Ruttley, T. M.

    2011-01-01

    With the retirement of the Space Shuttle and the transition of the International Space Station (ISS) from assembly to full laboratory capabilities, the opportunity to perform life science research in space has increased dramatically, while the operational considerations associated with transportation of the experiments has changed dramatically. US researchers have allocations on the European Automated Transfer Vehicle (ATV) and Japanese H-II Transfer Vehicle (HTV). In addition, the International Space Station (ISS) Cargo Resupply Services (CRS) contract will provide consumables and payloads to and from the ISS via the unmanned SpaceX (offers launch and return capabilities) and Orbital (offers only launch capabilities) resupply vehicles. Early requirements drove the capabilities of the vehicle providers; however, many other engineering considerations affect the actual design and operations plans. To better enable the use of the International Space Station as a National Laboratory, ground and on-orbit facility development can augment the vehicle capabilities to better support needs for cell biology, animal research, and conditioned sample return. NASA Life scientists with experience launching research on the space shuttle can find the trades between the capabilities of the many different vehicles to be confusing. In this presentation we will summarize vehicle and associated ground processing capabilities as well as key concepts of operations for different types of life sciences research being launched in the cargo vehicles. We will provide the latest status of vehicle capabilities and support hardware and facilities development being made to enable the broadest implementation of life sciences research on the ISS.

  19. The Influence Of Highway Transportation Infrastructure Condition Toward Commodity Production Generation for The Resilience Needs at Regional Internal Zone

    Science.gov (United States)

    Akbardin, Juang; Parikesit, Danang; Riyanto, Bambang; Mulyono, Agus Taufik

    2018-02-01

    The poultry commodity consumption and requirement is one of the main commodities that must be fulfilled in a region to maintain the availability of meat from poultry. Poultry commodity production is one of the production sectors that have a clean environment resistance. An increasing of poultry commodity generation production requires a smooth distribution to arrive at the processing. The livestock location as a commodity production is placed at a considerable far distance from residential and market locations. Zones that have poultry commodity production have an excess potential to supply other zones that are lacking in production to the consumption of these commodities. The condition of highway transportation infrastructure that is very diverse with the damage level availability in a zone has an influence in the supply and demand of poultry commodity requirement in the regional internal of Central Java province. In order to know the effect of highway transportation infrastructure condition toward the poultry commodity movement, demography factor and availability of freight vehicles will be reviewed to estimate the amount of poultry commodity movement generation production. Thus the poultry commodity consumption requirement that located in the internal - regional zone of central java province can be adequated from the zone. So it can be minimized the negative impacts that affect the environment at the zone in terms of comparison of the movement attraction and generation production at poultry commodity in Central Java.

  20. Influence of dispersion of nonlinearity on coherent supercontinuum generation bandwidth in photonic crystal fibers pumped at 2 μm

    DEFF Research Database (Denmark)

    Klimczak, Mariusz; Siwicki, Bartlomiej; Zhou, Binbin

    2017-01-01

    Sources of spectrally broadband and coherent light are necessary for frequency metrology and ultrashort pulse generation. Near-infrared (NIR) wavelengths are practical for such devices because of the emergence of robust and reasonably priced femtosecond lasers operating in this part of spectrum...... lasers as pump sources, exceeding the 2400 nm barrier has proved a challenge. ANDi SC requires strong nonlinear response of the optical material, since self-phase modulation (SPM) and optical wave breaking (OWB) mediated four-wave mixing (FWM) are almost exclusively shaping the ANDi SC pulses. Flatness...

  1. Determination of plutonium by secondary coulometric titration with internally generated iron(II) Pt. 2

    International Nuclear Information System (INIS)

    Chitnis, R.T.; Talnikar, S.G.; Thakur, V.A.; Paranjape, A.H.

    1979-01-01

    Determination of plutonium by secondary coulometry involving the controlled potential technique for the generation of an iron(II) mediator, is reported in Part I. In this paper, the same determination is reported using constant current coulometry for the generation of the mediator, and zero current potentiometry for end-point detection. The factors affecting the current efficiency, viz. current density and supporting electrolyte composition have been checked in order to define the appropriate conditions for obtaining 100% current efficiency. The original method of Carson et al. suffers from the disadvantage that it involves complicated sample treatment. Introduction of perchloric acid treatment as a method for the oxidation of plutonium and the pretitration of the supporting electrolyte to the end-point potential prior to sample addition, have considerably helped to improve the precision and accuracy of the method. Exhaustive analytical data are reported covering plutonium quantities ranging from 25 micrograms to 5 milligrams, which establishes the scope of the method. (author)

  2. Photonic crystal fibers

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper; Hansen, K P; Nielsen, M D

    2003-01-01

    Photonic crystal fibers having a complex microstructure in the transverse plane constitute a new and promising class of optical fibers. Such fibers can either guide light through total internal reflection or the photonic bandgap effect, In this paper, we review the different types and applications...... of photonic crystal fibers with particular emphasis on recent advances in the field....

  3. Marginal and internal fit of cobalt-chromium fixed dental prostheses generated from digital and conventional impressions.

    Science.gov (United States)

    Svanborg, Per; Skjerven, Henrik; Carlsson, Pablo; Eliasson, Alf; Karlsson, Stig; Ortorp, Anders

    2014-01-01

    Objectives. Digital impressions are increasingly used and have the potential to avoid the problem of inaccurate impressions. Only a few studies to verify the accuracy of digital impressions have been performed. The purpose of this study was to compare the marginal and internal fit of 3-unit tooth supported fixed dental prostheses (FDPs) fabricated from digital and conventional impressions. Methods. Ten FDPs were produced from digital impressions using the iTero system and 10 FDPs were produced using vinyl polysiloxane (VPS) impression material. A triple-scan protocol and CAD software were used for measuring and calculating discrepancies of the FDPs at 3 standard areas: mean internal discrepancy, absolute marginal gap, and cervical area discrepancy. The Mann-Whitney U test was used for analyzing the results. Results. For conventional and digital impressions, respectively, FDPs had an absolute marginal gap of 147  μ m and 142  μ m, cervical area discrepancy of 69  μ m and 44  μ m, and mean internal discrepancy of 117  μ m and 93  μ m. The differences were statistically significant in the cervical and internal areas (P digital impression technique is more exact and can generate 3-unit FDPs with a significantly closer fit compared to the VPS technique.

  4. Marginal and Internal Fit of Cobalt-Chromium Fixed Dental Prostheses Generated from Digital and Conventional Impressions

    Directory of Open Access Journals (Sweden)

    Per Svanborg

    2014-01-01

    Full Text Available Objectives. Digital impressions are increasingly used and have the potential to avoid the problem of inaccurate impressions. Only a few studies to verify the accuracy of digital impressions have been performed. The purpose of this study was to compare the marginal and internal fit of 3-unit tooth supported fixed dental prostheses (FDPs fabricated from digital and conventional impressions. Methods. Ten FDPs were produced from digital impressions using the iTero system and 10 FDPs were produced using vinyl polysiloxane (VPS impression material. A triple-scan protocol and CAD software were used for measuring and calculating discrepancies of the FDPs at 3 standard areas: mean internal discrepancy, absolute marginal gap, and cervical area discrepancy. The Mann-Whitney U test was used for analyzing the results. Results. For conventional and digital impressions, respectively, FDPs had an absolute marginal gap of 147 μm and 142 μm, cervical area discrepancy of 69 μm and 44 μm, and mean internal discrepancy of 117 μm and 93 μm. The differences were statistically significant in the cervical and internal areas (P<0.001. Significance. The results indicated that the digital impression technique is more exact and can generate 3-unit FDPs with a significantly closer fit compared to the VPS technique.

  5. Effects of Surfactant Contamination on the Next Generation Gas Trap for the ISS Internal Thermal Control System

    Science.gov (United States)

    Leimkuehler, Thomas O.; Lukens, Clark; Reeves, Daniel R.; Holt, James M.

    2004-01-01

    The current dual-membrane gas trap is designed to remove non-condensed gas bubbles from the Internal Thermal Control System (ITCS) coolant on board the International Space Station (ISS). To date it has successfully served its purpose of preventing gas bubbles from causing depriming, overspeed, and shutdown of the ITCS pump. However, contamination in the ITCS coolant has adversely affected the gas venting rate and lifetime of the gas trap, warranting a development effort for a next-generation gas trap. Previous testing has shown that a hydrophobic-only design is capable of performing even better than the current dual-membrane design for both steady-state gas removal and gas slug removal in clean deionized water. This paper presents results of testing to evaluate the effects of surfactant contamination on the steady-state performance of the hydrophobic-only design.

  6. Generation of Internal Waves by Buoyant Bubbles in Galaxy Clusters and Heating of Intracluster Medium

    Science.gov (United States)

    Zhang, Congyao; Churazov, Eugene; Schekochihin, Alexander A.

    2018-05-01

    Buoyant bubbles of relativistic plasma in cluster cores plausibly play a key role in conveying the energy from a supermassive black hole to the intracluster medium (ICM) - the process known as radio-mode AGN feedback. Energy conservation guarantees that a bubble loses most of its energy to the ICM after crossing several pressure scale heights. However, actual processes responsible for transferring the energy to the ICM are still being debated. One attractive possibility is the excitation of internal waves, which are trapped in the cluster's core and eventually dissipate. Here we show that a sufficient condition for efficient excitation of these waves in stratified cluster atmospheres is flattening of the bubbles in the radial direction. In our numerical simulations, we model the bubbles phenomenologically as rigid bodies buoyantly rising in the stratified cluster atmosphere. We find that the terminal velocities of the flattened bubbles are small enough so that the Froude number Fr ≲ 1. The effects of stratification make the dominant contribution to the total drag force balancing the buoyancy force. Clear signs of internal waves are seen in the simulations. These waves propagate horizontally and downwards from the rising bubble, spreading their energy over large volumes of the ICM. If our findings are scaled to the conditions of the Perseus cluster, the expected terminal velocity is ˜100 - 200 km s-1 near the cluster cores, which is in broad agreement with direct measurements by the Hitomi satellite.

  7. Fuel cell systems and high-integrated combinations of internal combustion engines and generators for hybrid drives; Brennstoffzellensysteme und hoch integrierte Verbrennungsmotor/Generator-Kombinationen fueHybridantriebe

    Energy Technology Data Exchange (ETDEWEB)

    Treffinger, P.; Graef, M. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Stuttgart (Germany). Inst. fuer Fahrzeugkonzepte

    2005-07-01

    So called fuel cell hybrid vehicles can be regarded in general as electrical driven vehicles, equipped with a fuel cell as current source, which is connected in parallel with an electrical energy storage. This power train configuration gives very high flexibility realizing the package, because the primary energy converter is not directly connected with the torque converter for propulsion. The studies 'Hy-Wire' and 'Sequel' of GM are adopting this approach as well as the modular vehicle concept of DLR Institute of Vehicle Concepts. The overall efficiency of the above described power train concept depends strongly on the efficiency of the current source. The efficiency potential of Polymer Electrolyte Fuel Cell (PEFC) systems has been successfully demonstrated by several car manufacturers. However, some technical issues are still to be solved, e.g. operation at low temperatures and power densities of the complete system. There is also no satisfying solution for the on-board storage of hydrogen. A current source based on a free piston linear generator is an alternative to the PEFC system. The free piston linear generator can be realized in several configurations. The approach of DLR, which is explained in this paper, enables the stroke to be adjusted according to the actual load. This especially improves internal efficiency significantly in partial loading conditions and also reduces heat losses. On the base of detailed simulation, underlined by first experimental studies, efficiencies above 35% in a broad operation range are estimated. (orig.)

  8. The International conference on fast reactors and related fuel cycles: next generation nuclear systems for sustainable development. Book of abstracts

    International Nuclear Information System (INIS)

    2017-01-01

    The materials of the International Conference on Fast Reactors and Related Fuel Cycles (June 26-29, 2017, Yekaterinburg) are presented. The forum was organized by the IAEA with the assistance of Rosatom State Corporation. The theme of the conference: “The New Generation of Nuclear Systems for Sustainable Development”. About 700 specialists from more than 30 countries took part in the conference. The state and prospects for the development of the direction of fast reactors in countries dealing with this topic were discussed. A wide range of scientific issues covered the concepts of prospective reactors, reactor cores, fuel and fuel cycles, operation and decommissioning, safety, licensing, structural materials, industrial implementation [ru

  9. Incorporating Environmental Justice into Second Generation Indices of Multiple Deprivation: Lessons from the UK and Progress Internationally

    Directory of Open Access Journals (Sweden)

    Jon Fairburn

    2016-07-01

    Full Text Available Second generation area-based indices of multiple deprivation have been extensively used in the UK over the last 15 years. They resulted from significant developments in political, technical, and conceptual spheres for deprivation data. We review the parallel development of environmental justice research and how and when environmental data was incorporated into these indices. We explain the transfer of these methods from the UK to Germany and assess the progress internationally in developing such indices. Finally, we illustrate how billions of pounds in the UK was allocated by using these tools to tackle neighbourhood deprivation and environmental justice to address the determinants of health.

  10. Cutting-in control of the variable speed constant frequency wind power generator based on internal model controller

    Energy Technology Data Exchange (ETDEWEB)

    Guo Jindong; Xu Honghua; Zhao Dongli [Inst. of Electrical Engineering, CAS, BJ (China)

    2008-07-01

    The no-impact-current cutting-in-network control is the key of variable speed constant frequency (VSCF) wind power control system. Based on the stator flux linkage oriented control theory of doubly fed induction generator (DFIG), the field-oriented vector control technique and the internal model controller (IMC) are transplanted into the voltage control of DFIG and a novel cutting-in control strategy is obtained. The strategy does not need the exact inductor generator model, and has perfect performance without overshoot. The structure of the controller is simple, and the only parameter to be adjusted is directly related to system performance, so the strategy is easy to realize. Finally the strategy is studied by simulation using Matlab, the results of the simulation show that the control strategy can effectively control the stator voltage. (orig.)

  11. GENIE - Generation of computational geometry-grids for internal-external flow configurations

    Science.gov (United States)

    Soni, B. K.

    1988-01-01

    Progress realized in the development of a master geometry-grid generation code GENIE is presented. The grid refinement process is enhanced by developing strategies to utilize bezier curves/surfaces and splines along with weighted transfinite interpolation technique and by formulating new forcing function for the elliptic solver based on the minimization of a non-orthogonality functional. A two step grid adaptation procedure is developed by optimally blending adaptive weightings with weighted transfinite interpolation technique. Examples of 2D-3D grids are provided to illustrate the success of these methods.

  12. Third generation constructivism and the rhetoric of inquiry in international relations

    OpenAIRE

    Michel, Torsten

    2016-01-01

    This article argues that third generation constructivism can make a central and overdue contribution to the practice of meta-theorising in IR. Meta-theory has so far restricted itself to exercises of observational re ection or de nitional sedimentation of content, or in Patrick Jackson’s words, to an elaboration of the ‘conduct of inquiry’. It has thereby failed, to its detriment, to re ect on and recognise the central importance of the deep and intricate relation between the content of meta-...

  13. Rb2Na(NO33: A Congruently Melting UV-NLO Crystal with a Very Strong Second-Harmonic Generation Response

    Directory of Open Access Journals (Sweden)

    Guohong Zou

    2016-04-01

    Full Text Available Crystals of congruently melting noncentrosymmetric (NCS mixed alkali metal nitrate, Rb2Na(NO33, have been grown through solid state reactions. The material possesses layers with NaO8 hexagonal bipyramids and NO3 triangular units. Rb+ cations are residing in the interlayer space. Each NaO8 hexagonal bipyramid shares its corners and edges with two and three NO3 units, respectively, in order to fulfill a highly dense stacking in the unit cell. The NaO8 groups share their six oxygen atoms in equatorial positions with three different NO3 groups to generate a NaO6-NO3 layer with a parallel alignment. The optimized arrangement of the NO3 groups and their high density in the structure together produce a strong second-harmonic generation (SHG response. Powder SHG measurements indicate that Rb2Na(NO33 has a strong SHG efficiency of five times that of KH2PO4 (KDP and is type I phase-matchable. The calculated average nonlinear optical (NLO susceptibility of Rb2Na(NO33 turns out to be the largest value among the NLO materials composed of only [NO3]− anion. In addition, Rb2Na(NO33 exhibits a wide transparency region ranging from UV to near IR, which suggests that the compound is a promising NLO material.

  14. Hydrogenation of the alpha,beta-Unsaturated Aldehydes Acrolein, Crotonaldehyde, and Prenal over Pt Single Crystals: A Kinetic and Sum-Frequency Generation Vibrational Spectroscopy Study

    Energy Technology Data Exchange (ETDEWEB)

    Kliewer, C.J.; Somorjai, G.A.

    2008-11-26

    Sum-frequency generation vibrational spectroscopy (SFG-VS) and kinetic measurements using gas chromatography have been used to study the surface reaction intermediates during the hydrogenation of three {alpha},{beta}-unsaturated aldehydes, acrolein, crotonaldehyde, and prenal, over Pt(111) at Torr pressures (1 Torr aldehyde, 100 Torr hydrogen) in the temperature range of 295K to 415K. SFG-VS data showed that acrolein has mixed adsorption species of {eta}{sub 2}-di-{sigma}(CC)-trans, {eta}{sub 2}-di-{sigma}(CC)-cis as well as highly coordinated {eta}{sub 3} or {eta}{sub 4} species. Crotonaldehyde adsorbed to Pt(111) as {eta}{sub 2} surface intermediates. SFG-VS during prenal hydrogenation also suggested the presence of the {eta}{sub 2} adsorption species, and became more highly coordinated as the temperature was raised to 415K, in agreement with its enhanced C=O hydrogenation. The effect of catalyst surface structure was clarified by carrying out the hydrogenation of crotonaldehyde over both Pt(111) and Pt(100) single crystals while acquiring the SFG-VS spectra in situ. Both the kinetics and SFG-VS showed little structure sensitivity. Pt(100) generated more decarbonylation 'cracking' product while Pt(111) had a higher selectivity for the formation of the desired unsaturated alcohol, crotylalcohol.

  15. A compact, all-optical, THz wave generator based on self-modulation in a slab photonic crystal waveguide with a single sub-nanometer graphene layer.

    Science.gov (United States)

    Asadi, R; Ouyang, Z; Mohammd, M M

    2015-07-14

    We design a compact, all-optical THz wave generator based on self-modulation in a 1-D slab photonic crystal (PhC) waveguide with a single sub-nanometer graphene layer by using enhanced nonlinearity of graphene. It has been shown that at the bandgap edge of higher bands of a 1-D slab PhC, through only one sub-nanometer graphene layer we can obtain a compact, high modulation factor (about 0.98 percent), self-intensity modulator at a high frequency (about 0.6 THz) and low threshold intensity (about 15 MW per square centimeter), and further a compact, all-optical THz wave generator by integrating the self-modulator with a THz photodiode or photonic mixer. Such a THz source is expected to have a relatively high efficiency compared with conventional sources based on optical methods. The proposed THz source can find wide applications in THz science and technology, e.g., in THz imaging, THz sensors and detectors, THz communication systems, and THz optical integrated logic circuits.

  16. Stabilized soliton self-frequency shift and 0.1- PHz sideband generation in a photonic-crystal fiber with an air-hole-modified core.

    Science.gov (United States)

    Liu, Bo-Wen; Hu, Ming-Lie; Fang, Xiao-Hui; Li, Yan-Feng; Chai, Lu; Wang, Ching-Yue; Tong, Weijun; Luo, Jie; Voronin, Aleksandr A; Zheltikov, Aleksei M

    2008-09-15

    Fiber dispersion and nonlinearity management strategy based on a modification of a photonic-crystal fiber (PCF) core with an air hole is shown to facilitate optimization of PCF components for a stable soliton frequency shift and subpetahertz sideband generation through four-wave mixing. Spectral recoil of an optical soliton by a red-shifted dispersive wave, generated through a soliton instability induced by high-order fiber dispersion, is shown to stabilize the soliton self-frequency shift in a highly nonlinear PCF with an air-hole-modified core relative to pump power variations. A fiber with a 2.3-microm-diameter core modified with a 0.9-microm-diameter air hole is used to demonstrate a robust soliton self-frequency shift of unamplified 50-fs Ti: sapphire laser pulses to a central wavelength of about 960 nm, which remains insensitive to variations in the pump pulse energy within the range from 60 to at least 100 pJ. In this regime of frequency shifting, intense high- and low-frequency branches of dispersive wave radiation are simultaneously observed in the spectrum of PCF output. An air-hole-modified-core PCF with appropriate dispersion and nonlinearity parameters is shown to provide efficient four-wave mixing, giving rise to Stokes and anti-Stokes sidebands whose frequency shift relative to the pump wavelength falls within the subpetahertz range, thus offering an attractive source for nonlinear Raman microspectroscopy.

  17. Efficient and broadband Stokes wave generation by degenerate four-wave mixing at the mid-infrared wavelength in a silica photonic crystal fiber.

    Science.gov (United States)

    Yuan, Jinhui; Sang, Xinzhu; Wu, Qiang; Zhou, Guiyao; Yu, Chongxiu; Wang, Kuiru; Yan, Binbin; Han, Ying; Farrell, Gerald; Hou, Lantian

    2013-12-15

    Based on degenerate four-wave mixing (FWM), the broadband Stokes waves are efficiently generated at the mid-infrared wavelength above 2 μm, for the first time to our knowledge, by coupling the femtosecond pulses into the fundamental mode of a silica photonic crystal fiber designed and fabricated in our laboratory. Influences of the power and wavelength of pump pulses on the phase-matched frequency conversion process are discussed. When pump pulses with central wavelength of 815 nm and average power of 300 mW are used, the output power ratio of the Stokes wave generated at 2226 nm and the residual pump wave P(s)/P(res) is estimated to be 10.8:1, and the corresponding conversion efficiency η(s) and bandwidth B(s) of the Stokes wave can be up to 26% and 33 nm, respectively. The efficient and broadband Stokes waves can be used as the ultrashort pulse sources for mid-infrared photonics and spectroscopy.

  18. Presence of renewable sources of energy, cogeneration, energy efficiency and distributed generation in the International Nuclear Information System (INIS)

    International Nuclear Information System (INIS)

    Pares Ferrer, Marianela; Oviedo Rivero, Irayda; Gonzalez Garcia, Alejandro

    2011-01-01

    The International Nuclear Information System (INIS) it was created in 1970 by the International Atomic Energy Agency (OIEA) with the objective of propitiating the exchange of scientific information and technique on the peaceful uses of the energy atomic. INIS processes most of scientific literature and technique in engineering matters nuclear, safeguard and non proliferation and applications in agriculture and health that it generates in the world and it contributes to create a repository of nuclear information for present and future generations. Additionally it includes economic aspects and environmental of other energy sources that facilitate comparative studies for the taking of decisions. The database INIS, is its main informative product and it counts with more than 3 million registrations. One of the services that lends the Center of Administration of the Information and Development of the Energy (CUBAENERGIA), like center INIS in Cuba, is the search of information on the peaceful use of the science and nuclear technology in the Countries Members and the registration of information on their applications in Cuba. More recently, it extends this service to the Renewable Sources application of Energy in the country; as part of the works of administration of the information that it carries out for the National Group of Renewable Energy, Cogeneration, Saving and Energy Efficiency, created in the 2007 and coordinated by the MINBAS with the participation of institutions belonging to Organisms of the Administration Central of the State. In this work the results of a preliminary study are presented on the witnesses in the INIS of the Renewable Sources of Energy, the Cogeneration, Energy Efficiency, and the Distributed Generation. As well as of the application of metric tools to the opposing registrations for the case of the Distributed generation, that which allowed to characterize their historical evolution, the participation for countries in their development and

  19. On-Orbit Measurement of Next Generation Space Solar Cell Technology on the International Space Station

    Science.gov (United States)

    Wolford, David S.; Myers, Matthew G.; Prokop, Norman F.; Krasowski, Michael J.; Parker, David S.; Cassidy, Justin C.; Davies, William E.; Vorreiter, Janelle O.; Piszczor, Michael F.; McNatt, Jeremiah S.

    2015-01-01

    Measurement is essential for the evaluation of new photovoltaic (PV) technology for space solar cells. NASA Glenn Research Center (GRC) is in the process of measuring several solar cells in a supplemental experiment on NASA Goddard Space Flight Center's (GSFC) Robotic Refueling Mission's (RRM) Task Board 4 (TB4). Four industry and government partners have provided advanced PV devices for measurement and orbital environment testing. The experiment will be on-orbit for approximately 18 months. It is completely self-contained and will provide its own power and internal data storage. Several new cell technologies including four- junction (4J) Inverted Metamorphic Multijunction (IMM) cells will be evaluated and the results compared to ground-based measurements.

  20. Conjugate transient natural convection in a cylindrical enclosure with internal volumetric heat generation

    International Nuclear Information System (INIS)

    Sharma, Anil Kumar; Velusamy, K.; Balaji, C.

    2008-01-01

    This paper reports the results of a numerical investigation of transient turbulent natural convection heat transfer from a volumetric energy generating source placed inside a cylindrical enclosure filled with low Prandtl number fluid (liquid sodium, Pr = 0.005). Two-dimensional conservation equations of mass, momentum and energy, coupled with the Boussinesq approximation, are solved using a finite volume based discretisation method employing the SIMPLE algorithm for the pressure velocity coupling. Turbulence is modeled using the k-ε model with physical boundary conditions. The study presents the transient features of confined turbulent natural convection, due to time varying generation of heat in the volumetric source. The intensity of heat source exponentially decays with time and the source is placed over circular plates with a central opening. Results obtained from the numerical model compare favorably with those reported in the literature for steady state natural convection. Numerical simulations are carried out to display the sequential evolution of flow and thermal fields and the maximum temperature reached in the source. The advantages of distributing the heat source on multi trays have been quantified

  1. International testicular cancer incidence trends: generational transitions in 38 countries 1900-1990.

    Science.gov (United States)

    Znaor, Ariana; Lortet-Tieulent, Joannie; Laversanne, Mathieu; Jemal, Ahmedin; Bray, Freddie

    2015-01-01

    Rapid increases in testicular cancer incidence have marked the second half of the last century. While these secular rises, observed mainly in countries attaining the highest levels of human development, appear to have attenuated in the last decade, rates continue to increase in countries transiting toward high developmental levels. The purpose of our study was to provide a comprehensive analysis and presentation of the cohort-specific trends in testicular cancer incidence rates in 38 countries worldwide. We used an augmented version of the Cancer Incidence in Five Continents series to analyze testicular cancer incidence in men aged 15-54 in 38 countries, via age-period-cohort analysis. In many European countries, the USA, Canada, Australia, and New Zealand, there is a continuation of the increasing risk among successive generations, yet rates are attenuating in male cohorts born since the 1970s in several Northern European countries, in contrast to the steeply increasing trends in recent cohorts in Southern Europe. Incidence rates have also been increasing in the populations traditionally at rather low risk, such as in the Philippines, Singapore, China, and Costa Rica. The attenuation of testicular cancer risk in younger generations (in the most developed countries) alongside concomitant increases (in countries undergoing developmental change) is indicative of a global transition in the risk of testicular cancer. While identifying the underlying causes remains a major challenge, increasing awareness and adapting national healthcare systems to accommodate a growing burden of testicular cancer may prevent future avoidable deaths in young men.

  2. Negative BOLD in sensory cortices during verbal memory: a component in generating internal representations?

    Science.gov (United States)

    Azulay, Haim; Striem, Ella; Amedi, Amir

    2009-05-01

    People tend to close their eyes when trying to retrieve an event or a visual image from memory. However the brain mechanisms behind this phenomenon remain poorly understood. Recently, we showed that during visual mental imagery, auditory areas show a much more robust deactivation than during visual perception. Here we ask whether this is a special case of a more general phenomenon involving retrieval of intrinsic, internally stored information, which would result in crossmodal deactivations in other sensory cortices which are irrelevant to the task at hand. To test this hypothesis, a group of 9 sighted individuals were scanned while performing a memory retrieval task for highly abstract words (i.e., with low imaginability scores). We also scanned a group of 10 congenitally blind, which by definition do not have any visual imagery per se. In sighted subjects, both auditory and visual areas were robustly deactivated during memory retrieval, whereas in the blind the auditory cortex was deactivated while visual areas, shown previously to be relevant for this task, presented a positive BOLD signal. These results suggest that deactivation may be most prominent in task-irrelevant sensory cortices whenever there is a need for retrieval or manipulation of internally stored representations. Thus, there is a task-dependent balance of activation and deactivation that might allow maximization of resources and filtering out of non relevant information to enable allocation of attention to the required task. Furthermore, these results suggest that the balance between positive and negative BOLD might be crucial to our understanding of a large variety of intrinsic and extrinsic tasks including high-level cognitive functions, sensory processing and multisensory integration.

  3. Multi-point laser spark generation for internal combustion engines using a spatial light modulator

    International Nuclear Information System (INIS)

    Lyon, Elliott; Kuang, Zheng; Dearden, Geoff; Cheng, Hua; Page, Vincent; Shenton, Tom

    2014-01-01

    This paper reports on a technique demonstrating for the first time successful multi-point laser-induced spark generation, which is variable in three dimensions and derived from a single laser beam. Previous work on laser ignition of internal combustion engines found that simultaneously igniting in more than one location resulted in more stable and faster combustion – a key potential advantage over conventional spark ignition. However, previous approaches could only generate secondary foci at fixed locations. The work reported here is an experimental technique for multi-point laser ignition, in which several sparks with arbitrary spatial location in three dimensions are created by variable diffraction of a pulsed single laser beam source and transmission through an optical plug. The diffractive multi-beam arrays and patterns are generated using a spatial light modulator on which computer generated holograms are displayed. A gratings and lenses algorithm is used to accurately modulate the phase of the input laser beam and create multi-beam output. The underpinning theory, experimental arrangement and results obtained are presented and discussed. (paper)

  4. Laser stimulated third harmonic generation studies in ZnO-Ta2O5-B2O3 glass ceramics entrenched with Zn3Ta2O8 crystal phases

    Science.gov (United States)

    Siva Sesha Reddy, A.; Jedryka, J.; Ozga, K.; Ravi Kumar, V.; Purnachand, N.; Kityk, I. V.; Veeraiah, N.

    2018-02-01

    In this study zinc borate glasses doped with different concentrations Ta2O5 were synthesized and were crystallized by heat treatment for prolonged times. The samples were characterized by XRD, SEM, IR and Raman spectroscopy techniques. The SEM images of the crystallized samples have indicated that the samples contain randomly distributed crystal grains with size ∼1 μm entrenched in the residual amorphous phase. XRD studies have exhibited diffraction peaks identified as being due to the reflections from (1 1 1) planes of monoclinic Zn3Ta2O8 crystal phase that contains intertwined tetrahedral zinc and octahedral tantalate structural units. The concentration of such crystal phases in the bulk samples is observed to increase with increase of Ta2O5 up to 3.0 mol%. The IR and Raman spectroscopy studies have confirmed the presence of ZnO4 and TaO6 structural units in the glass network in addition to the conventional borate structural units. For measuring third harmonic generation (THG) in the samples, the samples were irradiated with 532 nm laser beam and the intensity of THG of probing beam (Nd:YAG λ = 1064 nm 20 ns pulsed laser (ω)) is measured as a function of fundamental beam power varying up to 200 J/m2. The intensity of THG is found to be increasing with increase of fundamental beam power and found to be the maximal for the glass crystallized with 3.0 mol% of Ta2O5. The intensity of THG of the ceramicized samples is found to be nearly 5 times higher with respect to that of pre-crystallized samples. The generation of 3ω is attributed to the perturbation/interaction between Zn3Ta2O8 anisotropic crystal grains and the incident probing beam.

  5. High-Pressure Catalytic Reactions of C6 Hydrocarbons on PlatinumSingle-Crystals and nanoparticles: A Sum Frequency Generation VibrationalSpectroscopic and Kinetic Study

    Energy Technology Data Exchange (ETDEWEB)

    Bratlie, Kaitlin [Univ. of California, Berkeley, CA (United States)

    2007-01-01

    Catalytic reactions of cyclohexene, benzene, n-hexane, 2-methylpentane, 3-methylpentane, and 1-hexene on platinum catalysts were monitored in situ via sum frequency generation (SFG) vibrational spectroscopy and gas chromatography (GC). SFG is a surface specific vibrational spectroscopic tool capable of monitoring submonolayer coverages under reaction conditions without gas-phase interference. SFG was used to identify the surface intermediates present during catalytic processes on Pt(111) and Pt(100) single-crystals and on cubic and cuboctahedra Pt nanoparticles in the Torr pressure regime and at high temperatures (300K-450K). At low pressures (<10-6 Torr), cyclohexene hydrogenated and dehydrogenates to form cyclohexyl (C6H11) and π-allyl C6H9, respectively, on Pt(100). Increasing pressures to 1.5 Torr form cyclohexyl, π-allyl C6H9, and 1,4-cyclohexadiene, illustrating the necessity to investigate catalytic reactions at high-pressures. Simultaneously, GC was used to acquire turnover rates that were correlated to reactive intermediates observed spectroscopically. Benzene hydrogenation on Pt(111) and Pt(100) illustrated structure sensitivity via both vibrational spectroscopy and kinetics. Both cyclohexane and cyclohexene were produced on Pt(111), while only cyclohexane was formed on Pt(100). Additionally, π-allyl c-C6H9 was found only on Pt(100), indicating that cyclohexene rapidly dehydrogenates on the (100) surface. The structure insensitive production of cyclohexane was found to exhibit a compensation effect and was analyzed using the selective energy transfer (SET) model. The SET model suggests that the Pt-H system donates energy to the E2u mode of free benzene, which leads to catalysis. Linear C6 (n-hexane, 2-methylpentane, 3-methylpentane, and 1-hexene) hydrocarbons were also investigated in the presence and absence of excess hydrogen on Pt

  6. Fast reactor development and worldwide cooperation in Generation-IV International Forum

    International Nuclear Information System (INIS)

    Sagayama, Yutaka

    2013-01-01

    Objectives of Gen-IV systems development: Goals: Four challenging technology goals have been defined to be applied to innovative nuclear reactor concepts in the 21st century: 1) Safety and Reliability (safe and reliable operation, no offsite emergency response); 2) Sustainability (effective fuel utilization, minimization of nuclear waste); 3) Proliferation Resistance & Physical Protection (to assure unattractive and the least desirable route for diversion or theft of weapons-usable materials, and provide increased physical protection against acts of terrorism); 4) Economic Competitiveness (life-cycle cost advantage over other energy resources). Phase: Each Generation-IV reactor system is one of three stages. 1) Viability Phase; 2) Performance Phase; 3) Demonstration Phase. Target: Commercial Deployment is expected around 2030s or beyond

  7. Single-phase convection heat transfer characteristics of pebble-bed channels with internal heat generation

    International Nuclear Information System (INIS)

    Meng Xianke; Sun Zhongning; Xu Guangzhan

    2012-01-01

    Graphical abstract: The core of the water-cooled pebble bed reactor is the porous channels which stacked with spherical fuel elements. The gaps between the adjacent fuel elements are complex because they are stochastic and often shift. We adopt electromagnetic induction heating method to overall heat the pebble bed. By comparing and analyzing the experimental data, we get the rule of power distribution and the rule of heat transfer coefficient with particle diameter, heat flux density, inlet temperature and working fluid's Re number. Highlights: ► We adopt electromagnetic induction heating method to overall heat the pebble bed to be the internal heat source. ► The ball diameter is smaller, the effect of the heat transfer is better. ► With Re number increasing, heat transfer coefficient is also increasing and eventually tends to stabilize. ► The changing of heat power makes little effect on the heat transfer coefficient of pebble bed channels. - Abstract: The reactor core of a water-cooled pebble bed reactor includes porous channels that are formed by spherical fuel elements. This structure has notably improved heat transfer. Due to the variability and randomness of the interstices in pebble bed channels, heat transfer is complex, and there are few studies regarding this topic. To study the heat transfer characters of pebble bed channels with internal heat sources, oxidized stainless steel spheres with diameters of 3 and 8 mm and carbon steel spheres with 8 mm diameters are used in a stacked pebble bed. Distilled water is used as a refrigerant for the experiments, and the electromagnetic induction heating method is used to heat the pebble bed. By comparing and analyzing the experimental results, we obtain the governing rules for the power distribution and the heat transfer coefficient with respect to particle diameter, heat flux density, inlet temperature and working fluid Re number. From fitting of the experimental data, we obtain the dimensionless average

  8. Ensembles generated from crystal structures of single distant homologues solve challenging molecular-replacement cases in AMPLE.

    Science.gov (United States)

    Rigden, Daniel J; Thomas, Jens M H; Simkovic, Felix; Simpkin, Adam; Winn, Martyn D; Mayans, Olga; Keegan, Ronan M

    2018-03-01

    Molecular replacement (MR) is the predominant route to solution of the phase problem in macromolecular crystallography. Although routine in many cases, it becomes more effortful and often impossible when the available experimental structures typically used as search models are only distantly homologous to the target. Nevertheless, with current powerful MR software, relatively small core structures shared between the target and known structure, of 20-40% of the overall structure for example, can succeed as search models where they can be isolated. Manual sculpting of such small structural cores is rarely attempted and is dependent on the crystallographer's expertise and understanding of the protein family in question. Automated search-model editing has previously been performed on the basis of sequence alignment, in order to eliminate, for example, side chains or loops that are not present in the target, or on the basis of structural features (e.g. solvent accessibility) or crystallographic parameters (e.g. B factors). Here, based on recent work demonstrating a correlation between evolutionary conservation and protein rigidity/packing, novel automated ways to derive edited search models from a given distant homologue over a range of sizes are presented. A variety of structure-based metrics, many readily obtained from online webservers, can be fed to the MR pipeline AMPLE to produce search models that succeed with a set of test cases where expertly manually edited comparators, further processed in diverse ways with MrBUMP, fail. Further significant performance gains result when the structure-based distance geometry method CONCOORD is used to generate ensembles from the distant homologue. To our knowledge, this is the first such approach whereby a single structure is meaningfully transformed into an ensemble for the purposes of MR. Additional cases further demonstrate the advantages of the approach. CONCOORD is freely available and computationally inexpensive, so

  9. An extraordinary locally generated nonlinear internal wave on the shelf of northern South China Sea from marine seismic observation

    Science.gov (United States)

    Tang, Q.

    2017-12-01

    A secondary nonlinear internal wave (NIW) on the continental shelf of northern South China Sea (SCS) is studied from high resolution seismic data. It is an extraordinary complex NIW combination of two mode-2 NIWs and an NIW of elevation within a short distance of 2 km. The most energetic part of the NIW could be regarded as a mode-2 NIW localized in the upper layer between 40 and 120 m with its onset at 92 km. The vertical particle velocity of 41 cm/s may exceed the critical value of wave breaking and thus collapse the strongest stratification followed by a series of processes including internal wave breaking, overturning, Kelvin-Helmholtz (KH) instability, stratification splitting, and re-stratification eventually. Among these processes, the shear induced KH billows are directly imaged using the seismic method for the first time. The stratification splitting and re-stratification show that the unstable stage lasts only for a few hours and several kilometers. No previous work has reported the wave of elevation occurred in the deep water of 370 m. Different from the periodical NIWs originated from Luzon Strait, this secondary NIW is most likely generated locally at the shelf break during ebb tide. This is also the first seismic observation that a locally generated NIW is analyzed in detail on the continental shelf of northern SCS. A more sophisticated numerical model is necessary to simulate the extraordinary NIW and its accompanying features.

  10. Internalization Mediation towards the Relationship between Entrepreneurial Action and Individual Performance for the Next Generation of Family Companies in Surabaya

    Directory of Open Access Journals (Sweden)

    Carolina Novi Mustikarini

    2017-06-01

    Full Text Available This study  examined the effect of entrepreneurial action for the performance of the next generation using the sample of students who joined the Family Business Community. In this study, there is a high contribution given by the role of entrepreneurship education in preparing the next generation in the family business. In addition, entrepreneurship education is considered possible through the process of internalization of the leaning process that is going on. For example, it is noted that entrepreneurial action can have a significant effect on the performance of the organization. In the context of the family business and entrepreneurial education at the University of Ciputra, both variables (entrepreneurial action and individual performance are necessary to be tested and therefore, the researcher finds it possible to cary out a research that is supposed to have a contribution to the family business. This study uses a hierarchical regression analysis, to test the stages of the mediation process. The results showed that most of relationships mediate internalization Entrepreneurial Action and Individual Performance.

  11. ACADEMIC PARTNERSHIP AND GENERATION OF SCIENTIFIC KNOWLEDGE: THE CASE OF THE INTERNATIONAL NETWORK OF RESEARCHERS ON COMPETITIVENESS

    Directory of Open Access Journals (Sweden)

    José Guadalupe Vargas Hernández

    2011-03-01

    Full Text Available This paper has the objective to demonstrate the contributions achieved by the International Network of Researchers in Competitiveness (INRCO in academic collaboration and scientific knowledge generation. Part of the assumption sustaining that economic globalization processes, information and communication technologies revolution lead to the increasing environmental complexity and uncertainty of a knowledge society. One answer is the study and analysis of competitiveness considered as the strategy to achieve higher levels of economic growth and socio-cultural development in all micro, meso and macro levels. The method used is the analytic-deductive based on the evidence of related data with the activity and results in publications of the International Network of Researchers in Competitiveness. Consequently, it has been adapted certain speculative notions in a theoretical analysis exploring the social dynamics of the scientific activities. It is concluded that the management of the researchers’ dynamic network is capable to generate, apply and recycle the critical knowledge and the assets of academic and scientific talent through a dynamic combination of resources that have a position inside the formal e informal borders and between these borders of participant academics and institutions.

  12. Generating Benefits and Negotiating Tensions through an International Doctoral Forum: A Sociological Analysis

    Directory of Open Access Journals (Sweden)

    Guanglun Michael Mu

    2016-02-01

    Full Text Available Workshops and seminars are widely-used forms of doctoral training. However, research with a particular focus on these forms of doctoral training is sporadic in the literature. There is little, if any, such research concerning the international context and participants’ own voices. Mindful of these lacunae in the literature, we write the current paper as a group of participants in one of a series of doctoral forums co-organised annually by Beijing Normal University, China and Queensland University of Technology, Australia. The paper voices our own experiences of participation in the doctoral forum. Data were drawn from reflections, journals, and group discussions of all 12 student and academic participants. These qualitative data were organised and analysed through Bourdieu’s notions of capital and field. Findings indicate that the doctoral forum created enabling and challenging social fields where participants accrued and exchanged various forms of capital and negotiated transient and complex power relations. In this respect, the sociological framework used provides a distinctive theoretical tool to conceptualise and analyse the benefits and tensions of participation in the doctoral forum. Knowledge built and lessons learned through our paper will provide implications and recommendations for future planning of, and participation in, the doctoral forum series and similar activities elsewhere.

  13. Evolution of a fracture network in an elastic medium with internal fluid generation and expulsion

    Science.gov (United States)

    Kobchenko, Maya; Hafver, Andreas; Jettestuen, Espen; Renard, François; Galland, Olivier; Jamtveit, Bjørn; Meakin, Paul; Dysthe, Dag Kristian

    2014-11-01

    A simple and reproducible analog experiment was used to simulate fracture formation in a low-permeability elastic solid during internal fluid/gas production, with the objective of developing a better understanding of the mechanisms that control the dynamics of fracturing, fracture opening and closing, and fluid transport. In the experiment, nucleation, propagation, and coalescence of fractures within an elastic gelatin matrix, confined in a Hele-Shaw cell, occurred due to CO2 production via fermentation of sugar, and it was monitored by optical means. We first quantified how a fracture network develops, and then how intermittent fluid transport is controlled by the dynamics of opening and closing of fractures. The gas escape dynamics exhibited three characteristic behaviors: (1) Quasiperiodic release of gas with a characteristic frequency that depends on the gas production rate but not on the system size. (2) A 1 /f power spectrum for the fluctuations in the total open fracture area over an intermediate range of frequencies (f ), which we attribute to collective effects caused by interaction between fractures in the drainage network. (3) A 1 /f2 power spectrum was observed at high frequencies, which can be explained by the characteristic behavior of single fractures.

  14. Evaluation of Electrochemically Generated Potable Water Disinfectants for Use on the International Space Station

    Science.gov (United States)

    Rodriquez, Branelle; Anderson, Molly; Adams, Niklas; Vega, Leticia; Botkin, Douglas

    2013-01-01

    Microbial contamination and subsequent growth in spacecraft water systems are constant concerns for missions involving human crews. The current potable water disinfectant for the International Space Station (ISS) is iodine; however, with the end of the Space Shuttle Program, there is a need to develop redundant biocide systems that do not require regular up-mass dependencies. Throughout the course of a year, four different electrochemical systems were investigated as a possible biocide for potable water on the ISS. Research has indicated that a wide variability exists with regards to efficacy in both concentration and exposure time of these disinfectants; therefore, baseline efficacy values were established. This paper describes a series of tests performed to establish optimal concentrations and exposure times for four disinfectants against single and mixed species planktonic and biofilm bacteria. Results of the testing determined whether these electrochemical disinfection systems are able to produce a sufficient amount of chemical in both concentration and volume to act as a biocide for potable water on the ISS.

  15. Observations of core modes during RF-generated internal transport barriers in Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Lynn, A G [Fusion Research Center, University of Texas at Austin, Austin, TX (United States); Phillips, P E [Fusion Research Center, University of Texas at Austin, Austin, TX (United States); Hubbard, A E [Plasma Science and Fusion Center, MIT, Cambridge, MA (United States); Wukitch, S J [Plasma Science and Fusion Center, MIT, Cambridge, MA (United States)

    2004-05-01

    In the Alcator C-Mod tokamak, a high-resolution heterodyne ECE radiometer has been used to measure the electron temperature in plasma discharges with internal transport barriers (ITBs). ITBs are formed by the application of off-axis (r/a {approx} 0.5) ICRF power. Strong density peaking indicates the formation of the ITB. When the ITB is formed, the ECE radiometer detects a small amplitude mode localized near the magnetic axis. Surprisingly, as this mode amplitude grows a dip in the temperature profile is clearly observed at the same location. If sawteeth are present, the mode amplitude appears to be suppressed by the sawtooth crash and no dip in the temperate profiles is observed. TORAY, a ray-tracing code, has been used to investigate the possible refractive effects of the steep density gradients in the ITB and its effects on the ECE observations. The results show that refractive effects can explain the observed local changes in temperature. Ray-tracing also indicates that the observed modes are density fluctuations. Observations of broadband density fluctuations during 4.5 T ITBs are also described.

  16. Production of internal transport barriers via self-generated mean flows in Alcator C-Moda)

    Science.gov (United States)

    Fiore, C. L.; Ernst, D. R.; Podpaly, Y. A.; Mikkelsen, D.; Howard, N. T.; Lee, Jungpyo; Reinke, M. L.; Rice, J. E.; Hughes, J. W.; Ma, Y.; Rowan, W. L.; Bespamyatnov, I.

    2012-05-01

    New results suggest that changes observed in the intrinsic toroidal rotation influence the internal transport barrier (ITB) formation in the Alcator C-Mod tokamak [E. S. Marmar and Alcator C-Mod group, Fusion Sci. Technol. 51, 261 (2007)]. These arise when the resonance for ion cyclotron range of frequencies (ICRF) minority heating is positioned off-axis at or outside of the plasma half-radius. These ITBs form in a reactor relevant regime, without particle or momentum injection, with Ti ≈ Te, and with monotonic q profiles (qmin 1.5 × 105 rad/s) in the region where the ITB foot is observed. Gyrokinetic analyses indicate that this spontaneous shearing rate is comparable to the linear ion temperature gradient (ITG) growth rate at the ITB location and is sufficient to reduce the turbulent particle and energy transport. New and detailed measurement of the ion temperature demonstrates that the radial profile flattens as the ICRF resonance position moves off axis, decreasing the drive for the ITG the instability as well. These results are the first evidence that intrinsic rotation can affect confinement in ITB plasmas.

  17. FY 1999 Report on feasibility research and development for next generation liquid crystal process basic technologies; 1999 nendo jisedai ekisho process kiban gijutsu ni kakawaru sendo kenkyu kaihatsu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    Described herein are the FY 1999 results of the feasibility study on the next generation liquid crystal processes. Technology for low-temperature thin film formation fabricates high-purity, high-density Si films useful as the laser annealing (crystallization) precursor by the IBD method, without using thermal annealing. Formation of thin films of a-Si and SiNx on substrates kept at 200 degrees C or lower is studied using a high-density plasma source, and the surface conditions are uniformly controlled over a large area of the film precursor. The new technology needs less power to produce the film than the conventional CVD method which uses parallel flat plates by controlling the plasma-generating region. Resources- and energy-saving using the TFT method are essential for production of liquid-crystal displays, and the techniques for forming the thin films at low temperature are studied. Reduction in wiring resistance (signal transmission delay) is studied for the next generation TFT, and it is found that the Cu film is selectively formed on TiN but not on SiO{sub 2} by the MOCVD method at 150 to 180 degrees C. Similarly, the selective film formation is confirmed in the plating technology. The comprehensive investigations for the next generation liquid crystal process technologies cover high-quality polycrystalline Si films and lithography (exposed to light). (NEDO)

  18. Net Influence of an Internally Generated Guasi-biennial Oscillation on Modelled Stratospheric Climate and Chemistry

    Science.gov (United States)

    Hurwitz, Margaret M.; Oman, Luke David; Newman, Paul A.; Song, InSun

    2013-01-01

    A Goddard Earth Observing System Chemistry- Climate Model (GEOSCCM) simulation with strong tropical non-orographic gravity wave drag (GWD) is compared to an otherwise identical simulation with near-zero tropical non-orographic GWD. The GEOSCCM generates a quasibiennial oscillation (QBO) zonal wind signal in response to a tropical peak in GWD that resembles the zonal and climatological mean precipitation field. The modelled QBO has a frequency and amplitude that closely resembles observations. As expected, the modelled QBO improves the simulation of tropical zonal winds and enhances tropical and subtropical stratospheric variability. Also, inclusion of the QBO slows the meridional overturning circulation, resulting in a generally older stratospheric mean age of air. Slowing of the overturning circulation, changes in stratospheric temperature and enhanced subtropical mixing all affect the annual mean distributions of ozone, methane and nitrous oxide. Furthermore, the modelled QBO enhances polar stratospheric variability in winter. Because tropical zonal winds are easterly in the simulation without a QBO, there is a relative increase in tropical zonal winds in the simulation with a QBO. Extratropical differences between the simulations with and without a QBO thus reflect the westerly shift in tropical zonal winds: a relative strengthening of the polar stratospheric jet, polar stratospheric cooling and a weak reduction in Arctic lower stratospheric ozone.

  19. Power generation choices: an international perspective on costs, risks and externalities

    International Nuclear Information System (INIS)

    Carle, R.; Moynet, G.

    1994-01-01

    In France, as in other countries, it is no longer possible to discuss issues relating to the power or electricity generating sector without taking account of a wide range of sociological, political and environmental factors. Given the uncertainty regarding either the short-or long-term impact of such factors, analysts can no longer rely on forecasts and need to adopt an approach based on the use of extremely wide-ranging scenarios. Many researchers are currently examining ways in which these factors might be incorporated into economic calculations in the form of externalities. Such externalities cannot be properly taken into account, however, until we have reliable methods and databases with which to quantify them. At present they are taken into account implicitly. Thus the extensive nuclear power programme launched by the French Government in the 1970s was aimed at securing advantages in both economic and environmental terms. These advantages may be seen today in the structure of France's energy supply. (authors). 1 tab

  20. Production of internal transport barriers via self-generated mean flows in Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Fiore, C. L.; Ernst, D. R.; Podpaly, Y. A.; Howard, N. T.; Lee, Jungpyo; Reinke, M. L.; Rice, J. E.; Hughes, J. W.; Ma, Y. [MIT-PSFC, 77 Mass. Ave., Cambridge, Massachusetts 02139 (United States); Mikkelsen, D. [Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543-0451 (United States); Rowan, W. L.; Bespamyatnov, I. [FRC, U of Texas at Austin, Austin, Texas 78712 (United States)

    2012-05-15

    New results suggest that changes observed in the intrinsic toroidal rotation influence the internal transport barrier (ITB) formation in the Alcator C-Mod tokamak [E. S. Marmar and Alcator C-Mod group, Fusion Sci. Technol. 51, 261 (2007)]. These arise when the resonance for ion cyclotron range of frequencies (ICRF) minority heating is positioned off-axis at or outside of the plasma half-radius. These ITBs form in a reactor relevant regime, without particle or momentum injection, with Ti Almost-Equal-To Te, and with monotonic q profiles (q{sub min} < 1). C-Mod H-mode plasmas exhibit strong intrinsic co-current rotation that increases with increasing stored energy without external drive. When the resonance position is moved off-axis, the rotation decreases in the center of the plasma resulting in a radial toroidal rotation profile with a central well which deepens and moves farther off-axis when the ICRF resonance location reaches the plasma half-radius. This profile results in strong E Multiplication-Sign B shear (>1.5 Multiplication-Sign 10{sup 5} rad/s) in the region where the ITB foot is observed. Gyrokinetic analyses indicate that this spontaneous shearing rate is comparable to the linear ion temperature gradient (ITG) growth rate at the ITB location and is sufficient to reduce the turbulent particle and energy transport. New and detailed measurement of the ion temperature demonstrates that the radial profile flattens as the ICRF resonance position moves off axis, decreasing the drive for the ITG the instability as well. These results are the first evidence that intrinsic rotation can affect confinement in ITB plasmas.

  1. Nonlinear internal waves and plumes generated in response to sea-loch outflow, AUV, and time-lapse photography observations

    Science.gov (United States)

    Toberman, Matthew; Inall, Mark; Boyd, Tim; Dumount, Estelle; Griffiths, Colin

    2017-07-01

    The tidally modulated outflow of brackish water from a sea loch forms a thin surface layer that propagates into the coastal ocean as a buoyant gravity current, transporting nutrients and sediments, as well as fresh water, heat and momentum. The fresh intrusion both propagates into and generates a strongly stratified environment which supports trains of nonlinear internal waves (NLIWs). NLIWs are shown to propagate ahead of this buoyancy input in response to propagation of the outflow water into the stratified environment generated by the previous release as well as in the opposing direction after the reflection from steep bathymetry. Oblique aerial photographs were taken and photogrammetric rectification led to the identification of the buoyant intrusion and the subsequent generation of NLIWs. An autonomous underwater vehicle (AUV) was deployed on repeated reciprocal transects in order to make simultaneous CTD, ADCP, and microstructure shear measurements of the evolution of these phenomena in conjunction with conventional mooring measurements. AUV-based temperature and salinity signals of NLIWs of depression were observed together with increased turbulent kinetic energy dissipation rates of over 2 orders of magnitude within and in the wake of the NLIWs. Repeated measurements allow a unique opportunity to investigate the horizontal structure of these phenomena. Simple metric scaling demonstrates that these processes are likely to be feature of many fjordic systems located on the west coast of Scotland but may also play a key role in the assimilation of the outflow from many tidally dominated fjordic systems throughout the world.

  2. SECOND WASTE PACKAGE PROBABILISTIC CRITICALITY ANALYSIS: GENERATION AND EVALUATION OF INTERNAL CRITICIALITY CONFIGURATIONS

    Energy Technology Data Exchange (ETDEWEB)

    P. Gottlieb, J.R. Massari, J.K. McCoy

    1996-03-27

    This analysis is prepared by the Mined Geologic Disposal System (MGDS) Waste Package Development (WPD) department to provide an evaluation of the criticality potential within a waste package having sonic or all of its contents degraded by corrosion and removal of neutron absorbers. This analysis is also intended to provide an estimate of the consequences of any internal criticality, particularly in terms of any increase in radionuclide inventory. These consequence estimates will be used as part of the WPD input to the Total System Performance Assessment. The ultimate objective of this analysis is to augment the information gained from the Initial Waste Package Probabilistic Criticality Analyses (Ref. 5.8 and 5.9, hereafter referred to as IPA) to a degree which will support preliminary waste package design recommendations intended to reduce the risk of waste package criticality and the risk to total repository system performance posed by the consequences of any criticality. The IPA evaluated the criticality potential under the assumption that the waste package basket retained its structural integrity, so that the assemblies retained their initial separation, even when the neutron absorbers had been leached from the basket. This analysis is based on the more realistic condition that removal of the neutron absorbers is a consequence of the corrosion of the steel in which they are contained, which has the additional consequence of reducing the structural support between assemblies. The result is a set of more reactive configurations having a smaller spacing between assemblies, or no inter-assembly spacing at all. Another difference from the IPA is the minimal attention to probabilistic evaluation given in this study. Although the IPA covered a time horizon to 100,000 years, the lack of consideration of basket degradation modes made it primarily applicable to the first 10,000 years. In contrast, this study, by focusing on the degraded modes of the basket, is primarily

  3. Effect of carbon content on the microstructure and creep properties of a 3rd generation single crystal nickel-base superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.W.; Liu, T. [Superalloys Division, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Wang, L., E-mail: wangli@imr.ac.cn [Superalloys Division, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Liu, X.G.; Lou, L.H. [Superalloys Division, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Zhang, J. [Superalloys Division, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

    2015-07-15

    Effect of carbon content on the microstructure and creep properties of a 3rd generation single crystal nickel-base superalloy has been investigated by the scanning electron microscope, X-ray computed tomography and electron probe microanalyzer. With the increase of the carbon content, MC carbides evolve from octahedral to well-developed dendrite, which promotes the formation of microporosity. Moreover, the volume fraction of porosity increases in the experimental alloys after solution heat treatment. As a result, the increase in the size of MC carbides and the porosity has a detrimental effect on the low temperature and high stress creep behavior of the alloys. The specimen crept at 850 °C and 586 MPa with the carbon content of 430 ppm shows the shortest rupture life due to the largest primary creep strain. However, the creep behavior of the alloy at 1120 °C and 140 MPa gets better as the carbon content increases from 88 to 430 ppm. TCP phase is observed near the fracture surfaces of the alloys, which explores as a potential cause for the creep rupture. However, the formation of TCP phase is effectively suppressed for decreasing segregation of the alloying elements, which results in the improvement of the creep life in the alloy with 430 ppm carbon at 1120 °C and 140 MPa.

  4. Widely tunable broadband deep-ultraviolet to visible wavelength generation by the cross phase modulation in a hollow-core photonic crystal fiber cladding

    International Nuclear Information System (INIS)

    Yuan, J H; Sang, X Z; Wu, Q; Yu, C X; Shen, X W; Wang, K R; Yan, B B; Teng, Y L; Farrell, G; Zhou, G Y; Xia, C M; Han, Y; Li, S G; Hou, L T

    2013-01-01

    The deep-ultraviolet (UV) to visible wavelengths are efficiently generated for the first time by the cross phase modulation (XPM) between the red-shifted solitons and the blue-shifted dispersive waves (DWs) in the fundamental guided mode of the multi-knots of a hollow-core photonic crystal fiber cladding (HC-PCFC). When the femtosecond pulses with a wavelength of 850 nm and average power of 300 mW are coupled into the knots 1–3, the conversion efficiency η uv−v of 11% and bandwidth B uv−v of 100 nm in the deep-UV region are experimentally obtained. The multi-milliwatt ultrashort pulses are tunable over the deep-UV (below 200 nm) to visible spectral region by adjusting the wavelengths of the pump pulses in different knots. It is expected that these widely tunable broadband ultrashort deep-UV–visible pulse sources could have important applications in ultrafast photonics, femtochemisty, photobiology, and UV–visible resonant Raman scattering. (letter)

  5. Bunch by bunch beam monitoring in 3rd and 4th generation light sources by means of single crystal diamond detectors and quantum well devices

    Science.gov (United States)

    Antonelli, M.; Di Fraia, M.; Tallaire, A.; Achard, J.; Carrato, S.; Menk, R. H.; Cautero, G.; Giuressi, D.; Jark, W. H.; Biasiol, G.; Ganbold, T.; Oliver, K.; Callegari, C.; Coreno, M.; De Sio, A.; Pace, E.

    2012-10-01

    New generation Synchrotron Radiation (SR) sources and Free Electron Lasers (FEL) require novel concepts of beam diagnostics to keep photon beams under surveillance, asking for simultaneous position and intensity monitoring. To deal with high power load and short time pulses provided by these sources, novel materials and methods are needed for the next generation BPMs. Diamond is a promising material for the production of semitransparent in situ X-ray BPMs withstanding the high dose rates of SR rings and high energy FELs. We report on the development of freestanding, single crystal CVD diamond detectors. Performances in both low and radio frequency SR beam monitoring are presented. For the former, sensitivity deviation was found to be approximately 2%; a 0.05% relative precision in the intensity measurements and a 0.1-μm precision in the position encoding have been estimated. For the latter, single-shot characterizations revealed sub-nanosecond rise-times and spatial precisions below 6 μm, which allowed bunch-by-bunch monitoring in multi-bunch operation. Preliminary measurements at the Fermi FEL have been performed with this detector, extracting quantitative intensity and position information for FEL pulses (~ 100 fs, energy 12 ÷ 60 eV), with a long-term spatial precision of about 85 μm results on FEL radiation damages are also reported. Due to their direct, low-energy band gap, InGaAs quantum well devices too may be used as fast detectors for photons ranging from visible to X-ray. Results are reported which show the capability of a novel InGaAs/InAlAs device to detect intensity and position of 100-fs-wide laser pulses.

  6. Proceedings of the first MIT international conference on the next generation of nuclear power technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1990-07-01

    The overall goal of advanced nuclear reactor development is to provide technological options which will be broadly acceptable to the different interested communities - electric utilities, environmental protection interests and electricity consumers. These constituencies will differ greatly in their priorities and understandings of what is feasible. However they all will collectively determine the definition of what constitutes an acceptable technology. The purpose of the Conference reported here was to aid the process reaching a greater consensus concerning acceptable technologies. The Conference was structured to permit all of those involved to gain a common understanding of the performance attributes which can reasonably be expected from the next generation of nuclear power plants, and to assist the process of communication among the various interest groups - ranging from reactor manufacturers and electric utilities to groups which have been strongly critical of nuclear power. This Conference is the first of an indefinite series of Conferences to be sponsored by the Program. The purpose of having a series of Conferences is to permit them to serve as a vehicle for sustained discussion among the communities which will determine whether future nuclear power plants are acceptable as national strategic options. The hope in organizing these Conferences is to improve the technologies which will eventually emerge, as a consequence of early effective communication among those concerned with the results. In order to do this, however, it is necessary for the people involved in such communication to have opportunities for sustained exposure to the ideas of others whom they would not otherwise have met. To do this it is necessary that these various communities interact repeatedly. The Conference series is intended to assist in that process. The Conference consisted of six focused topical sessions and two panel discussions. In each topical session keynote and respondent papers

  7. Proceedings of the first MIT international conference on the next generation of nuclear power technology

    International Nuclear Information System (INIS)

    1990-01-01

    The overall goal of advanced nuclear reactor development is to provide technological options which will be broadly acceptable to the different interested communities - electric utilities, environmental protection interests and electricity consumers. These constituencies will differ greatly in their priorities and understandings of what is feasible. However they all will collectively determine the definition of what constitutes an acceptable technology. The purpose of the Conference reported here was to aid the process reaching a greater consensus concerning acceptable technologies. The Conference was structured to permit all of those involved to gain a common understanding of the performance attributes which can reasonably be expected from the next generation of nuclear power plants, and to assist the process of communication among the various interest groups - ranging from reactor manufacturers and electric utilities to groups which have been strongly critical of nuclear power. This Conference is the first of an indefinite series of Conferences to be sponsored by the Program. The purpose of having a series of Conferences is to permit them to serve as a vehicle for sustained discussion among the communities which will determine whether future nuclear power plants are acceptable as national strategic options. The hope in organizing these Conferences is to improve the technologies which will eventually emerge, as a consequence of early effective communication among those concerned with the results. In order to do this, however, it is necessary for the people involved in such communication to have opportunities for sustained exposure to the ideas of others whom they would not otherwise have met. To do this it is necessary that these various communities interact repeatedly. The Conference series is intended to assist in that process. The Conference consisted of six focused topical sessions and two panel discussions. In each topical session keynote and respondent papers

  8. Generation of 14  W at 589  nm by frequency doubling of high-power CW linearly polarized Raman fiber laser radiation in MgO:sPPLT crystal.

    Science.gov (United States)

    Surin, A A; Borisenko, T E; Larin, S V

    2016-06-01

    We introduce an efficient, single-mode, linearly polarized continuous wave (CW) Raman fiber laser (RFL), operating at 1178 nm, with 65 W maximum output power and a narrow linewidth of 0.1 nm. Single-pass second-harmonic generation was demonstrated using a 20 mm long MgO-doped stoichiometric periodically polled lithium tantalate (MgO:sPPLT) crystal pumped by RFL radiation. Output power of 14 W at 589 nm with 22% conversion efficiency was achieved. The possibility of further power scaling is considered, as no crystal degradation was observed at these power levels.

  9. Generation of 1.3 μm and 1.5 μm high-energy Raman radiations in α-BaTeMo2O9 crystals

    Science.gov (United States)

    Liu, Shande; Zhang, Junjie; Gao, Zeliang; Wei, Lei; Zhang, Shaojun; He, Jingliang; Tao, Xutang

    2014-02-01

    The generations of high energy 2nd- and 3rd-order stimulated Raman scattering lasers based on the α-BaTeMo2O9 crystal were demonstrated for the first time. The Raman gain coefficient has been compared with that of the YVO4 crystal. A maximum total Stokes radiation energy of 27.3 mJ was obtained, containing 20.1 mJ 2nd-order Stokes energy at 1318 nm, together with 7.2 mJ 3rd-order Stokes energy at 1497 nm, giving an overall conversion efficiency of 35.9% and a slope efficiency of 54.5%. With an optical coating design, a total 3rd- and 4th-order Stokes energy of 16.5 mJ was generated. The maximum energy for 4th-order Stokes radiation at 1731 nm was 2 mJ. The pulse durations for the 2nd-, 3rd-, and 4th-order Stokes shift were 10 ns, 8.6 ns, and 5.2 ns, respectively. Our experimental results show that the α-BTM crystal is a promising Raman crystal for the generations of eye-safe radiations.

  10. Total internal reflection sum-frequency generation spectroscopy and dense gold nanoparticles monolayer: a route for probing adsorbed molecules

    International Nuclear Information System (INIS)

    Tourillon, Gerard; Dreesen, Laurent; Volcke, Cedric; Sartenaer, Yannick; Thiry, Paul A; Peremans, Andre

    2007-01-01

    We show that sum-frequency generation spectroscopy performed in the total internal reflection configuration (TIR-SFG) combined with a dense gold nanoparticles monolayer allows us to study, with an excellent signal to noise ratio and high signal to background ratio, the conformation of adsorbed molecules. Dodecanethiol (DDT) was used as probe molecules in order to assess the potentialities of the approach. An enhancement of more than one order of magnitude of the SFG signals arising from the adsorbed species is observed with the TIR geometry compared to the external reflection one while the SFG non-resonant contribution remains the same for both configurations. Although further work is required to fully understand the origin of the SFG process on nanoparticles, our work opens new possibilities for studying nanostructures

  11. Resolving high-frequency internal waves generated at an isolated coral atoll using an unstructured grid ocean model

    Science.gov (United States)

    Rayson, Matthew D.; Ivey, Gregory N.; Jones, Nicole L.; Fringer, Oliver B.

    2018-02-01

    We apply the unstructured grid hydrodynamic model SUNTANS to investigate the internal wave dynamics around Scott Reef, Western Australia, an isolated coral reef atoll located on the edge of the continental shelf in water depths of 500,m and more. The atoll is subject to strong semi-diurnal tidal forcing and consists of two relatively shallow lagoons separated by a 500 m deep, 2 km wide and 15 km long channel. We focus on the dynamics in this channel as the internal tide-driven flow and resulting mixing is thought to be a key mechanism controlling heat and nutrient fluxes into the reef lagoons. We use an unstructured grid to discretise the domain and capture both the complex topography and the range of internal wave length scales in the channel flow. The model internal wave field shows super-tidal frequency lee waves generated by the combination of the steep channel topography and strong tidal flow. We evaluate the model performance using observations of velocity and temperature from two through water-column moorings in the channel separating the two reefs. Three different global ocean state estimate datasets (global HYCOM, CSIRO Bluelink, CSIRO climatology atlas) were used to provide the model initial and boundary conditions, and the model outputs from each were evaluated against the field observations. The scenario incorporating the CSIRO Bluelink data performed best in terms of through-water column Murphy skill scores of water temperature and eastward velocity variability in the channel. The model captures the observed vertical structure of the tidal (M2) and super-tidal (M4) frequency temperature and velocity oscillations. The model also predicts the direction and magnitude of the M2 internal tide energy flux. An energy analysis reveals a net convergence of the M2 energy flux and a divergence of the M4 energy flux in the channel, indicating the channel is a region of either energy transfer to higher frequencies or energy loss to dissipation. This conclusion is

  12. Assembly of disperse red 1 molecules in the channels of AlPO4-5 single crystals for second-harmonic generation

    NARCIS (Netherlands)

    Jiang, FY; Lu, WX; Zhai, JP; Ye, JT; Wong, GKL; Han, Xueyao; Tang, ZK

    2006-01-01

    Disperse red 1 (DR1) molecules have been successfully incorporated into the one-dimensional channels of AlPO4-5 single crystals by means of vapor-phase diffusion. Polarizing microscope and SHG results indicate that the DR1 molecules are well aligned in a preferred direction along the crystal

  13. Power generation and gaseous emissions performance of an internal combustion engine fed with blends of soybean and beef tallow biodiesel.

    Science.gov (United States)

    Schirmer, Waldir Nagel; Gauer, Mayara Ananda; Tomaz, Edson; Rodrigues, Paulo Rogério Pinto; de Souza, Samuel Nelson Melegari; Chaves, Luiz Inácio; Villetti, Lucas; Olanyk, Luciano Zart; Cabral, Alexandre Rodrigues

    2016-01-01

    This study aimed to compare the performance of an internal combustion engine fed with blends of biodiesel produced from soybean and diesel, and blends of biodiesel produced from beef tallow and diesel. Performance was evaluated in terms of power generated at low loading conditions (0.5, 1.0 and 1.5 kW) and emission of organic and inorganic pollutants. In order to analyse inorganic gases (CO, SO2 and NOx), an automatic analyser was used and the organic emissions (benzene, toluene, ethylbenzene and xylene - BTEX) were carried out using a gas chromatograph. The results indicate that the introduction of the two biodiesels in the fuel caused a reduction in CO, SO2 and BTEX emissions. In addition, the reduction was proportional to the increase in loading regime. Beef tallow biodiesels presented better results regarding emission than soybean biodiesels. The use of pure biodiesels also presented a net reduction in pollutant gas emissions without hindering the engine generator performance.

  14. Correction of the equilibrium temperature caused by slight evaporation of water in protein crystal growth cells during long-term space experiments at International Space Station.

    Science.gov (United States)

    Fujiwara, Takahisa; Suzuki, Yoshihisa; Yoshizaki, Izumi; Tsukamoto, Katsuo; Murayama, Kenta; Fukuyama, Seijiro; Hosokawa, Kouhei; Oshi, Kentaro; Ito, Daisuke; Yamazaki, Tomoya; Tachibana, Masaru; Miura, Hitoshi

    2015-08-01

    The normal growth rates of the {110} faces of tetragonal hen egg-white lysozyme crystals, R, were measured as a function of the supersaturation σ parameter using a reflection type interferometer under μG at the International Space Station (NanoStep Project). Since water slightly evaporated from in situ observation cells during a long-term space station experiment for several months, equilibrium temperature T(e) changed, and the actual σ, however, significantly increased mainly due to the increase in salt concentration C(s). To correct σ, the actual C(s) and protein concentration C(p), which correctly represent the measured T(e) value in space, were first calculated. Second, a new solubility curve with the corrected C(s) was plotted. Finally, the revised σ was obtained from the new solubility curve. This correction method successfully revealed that the 2.8% water was evaporated from the solution, leading to 2.8% increase in the C(s) and C(p) of the solution.

  15. EDITORIAL: The Fourth International Workshop on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS 2004)

    Science.gov (United States)

    Tanaka, Shuji; Toriyama, Toshiyuki

    2005-09-01

    This special issue of the Journal of Micromechanics and Microengineering features papers selected from the Fourth International Workshop on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS 2004). The workshop was held in Kyoto, Japan, on 28-30 November 2004, by The Ritsumeikan Research Institute of Micro System Technology in cooperation with The Global Emerging Technology Institute, The Institute of Electrical Engineers of Japan, The Sensors and Micromachines Society, The Micromachine Center and The Kyoto Nanotech Cluster. Power MEMS is one of the newest categories of MEMS, which encompasses microdevices and microsystems for power generation, energy conversion and propulsion. The first concept of power MEMS was proposed in the late 1990s by Epstein's group at the Massachusetts Institute of Technology, where they continue to study MEMS-based gas turbine generators. Since then, the research and development of power MEMS have been promoted by the need for compact power sources with high energy and power density. Since its inception, power MEMS has expanded to include not only various MEMS-based power generators but also small energy machines and microdevices for macro power generators. At the last workshop, various devices and systems, such as portable fuel cells and their peripherals, micro and small turbo machinery, energy harvesting microdevices, and microthrusters, were presented. Their power levels vary from ten nanowatts to hundreds of watts, spanning ten orders of magnitude. The first PowerMEMS workshop was held in 2000 in Sendai, Japan, and consisted of only seven invited presentations. The workshop has grown since then, and in 2004 there were 5 invited, 20 oral and 29 poster presentations. From the 54 papers in the proceedings, 12 papers have been selected for this special issue. I would like to express my appreciation to the members of the Organizing Committee and Technical Program Committee. This special issue was

  16. International

    International Nuclear Information System (INIS)

    Anon.

    1997-01-01

    This rubric reports on 10 short notes about international economical facts about nuclear power: Electricite de France (EdF) and its assistance and management contracts with Eastern Europe countries (Poland, Hungary, Bulgaria); Transnuclear Inc. company (a 100% Cogema daughter company) acquired the US Vectra Technologies company; the construction of the Khumo nuclear power plant in Northern Korea plays in favour of the reconciliation between Northern and Southern Korea; the delivery of two VVER 1000 Russian reactors to China; the enforcement of the cooperation agreement between Euratom and Argentina; Japan requested for the financing of a Russian fast breeder reactor; Russia has planned to sell a floating barge-type nuclear power plant to Indonesia; the control of the Swedish reactor vessels of Sydkraft AB company committed to Tractebel (Belgium); the renewal of the nuclear cooperation agreement between Swiss and USA; the call for bids from the Turkish TEAS electric power company for the building of the Akkuyu nuclear power plant answered by three candidates: Atomic Energy of Canada Limited (AECL), Westinghouse (US) and the French-German NPI company. (J.S.)

  17. Macromolecular crystallization in microgravity

    International Nuclear Information System (INIS)

    Snell, Edward H; Helliwell, John R

    2005-01-01

    Density difference fluid flows and sedimentation of growing crystals are greatly reduced when crystallization takes place in a reduced gravity environment. In the case of macromolecular crystallography a crystal of a biological macromolecule is used for diffraction experiments (x-ray or neutron) so as to determine the three-dimensional structure of the macromolecule. The better the internal order of the crystal then the greater the molecular structure detail that can be extracted. It is this structural information that enables an understanding of how the molecule functions. This knowledge is changing the biological and chemical sciences, with major potential in understanding disease pathologies. In this review, we examine the use of microgravity as an environment to grow macromolecular crystals. We describe the crystallization procedures used on the ground, how the resulting crystals are studied and the knowledge obtained from those crystals. We address the features desired in an ordered crystal and the techniques used to evaluate those features in detail. We then introduce the microgravity environment, the techniques to access that environment and the theory and evidence behind the use of microgravity for crystallization experiments. We describe how ground-based laboratory techniques have been adapted to microgravity flights and look at some of the methods used to analyse the resulting data. Several case studies illustrate the physical crystal quality improvements and the macromolecular structural advances. Finally, limitations and alternatives to microgravity and future directions for this research are covered. Macromolecular structural crystallography in general is a remarkable field where physics, biology, chemistry and mathematics meet to enable insight to the fundamentals of life. As the reader will see, there is a great deal of physics involved when the microgravity environment is applied to crystallization, some of it known, and undoubtedly much yet to

  18. Solid-solid phase transformation via internal stress-induced virtual melting, significantly below the melting temperature. Application to HMX energetic crystal.

    Science.gov (United States)

    Levitas, Valery I; Henson, Bryan F; Smilowitz, Laura B; Asay, Blaine W

    2006-05-25

    We theoretically predict a new phenomenon, namely, that a solid-solid phase transformation (PT) with a large transformation strain can occur via internal stress-induced virtual melting along the interface at temperatures significantly (more than 100 K) below the melting temperature. We show that the energy of elastic stresses, induced by transformation strain, increases the driving force for melting and reduces the melting temperature. Immediately after melting, stresses relax and the unstable melt solidifies. Fast solidification in a thin layer leads to nanoscale cracking which does not affect the thermodynamics or kinetics of the solid-solid transformation. Thus, virtual melting represents a new mechanism of solid-solid PT, stress relaxation, and loss of coherence at a moving solid-solid interface. It also removes the athermal interface friction and deletes the thermomechanical memory of preceding cycles of the direct-reverse transformation. It is also found that nonhydrostatic compressive internal stresses promote melting in contrast to hydrostatic pressure. Sixteen theoretical predictions are in qualitative and quantitative agreement with experiments conducted on the PTs in the energetic crystal HMX. In particular, (a) the energy of internal stresses is sufficient to reduce the melting temperature from 551 to 430 K for the delta phase during the beta --> delta PT and from 520 to 400 K for the beta phase during the delta --> beta PT; (b) predicted activation energies for direct and reverse PTs coincide with corresponding melting energies of the beta and delta phases and with the experimental values; (c) the temperature dependence of the rate constant is determined by the heat of fusion, for both direct and reverse PTs; results b and c are obtained both for overall kinetics and for interface propagation; (d) considerable nanocracking, homogeneously distributed in the transformed material, accompanies the PT, as predicted by theory; (e) the nanocracking does not

  19. Progress on photonic crystals

    CERN Document Server

    Lecoq, P; Gundacker, S; Hillemanns, H; Jarron, P; Knapitsch, A; Leclercq, J L; Letartre, X; Meyer, T; Pauwels, K; Powolny, F; Seassal, C

    2010-01-01

    The renewal of interest for Time of Flight Positron Emission Tomography (TOF PET) has highlighted the need for increasing the light output of scintillating crystals and in particular for improving the light extraction from materials with a high index of refraction. One possible solution to overcome the problem of total internal reflection and light losses resulting from multiple bouncing within the crystal is to improve the light extraction efficiency at the crystal/photodetector interface by means of photonic crystals, i.e. media with a periodic modulation of the dielectric constant at the wavelength scale. After a short reminder of the underlying principles this contribution proposes to present the very encouraging results we have recently obtained on LYSO pixels and the perspectives on other crystals such as BGO, LuYAP and LuAG. These results confirm the impressive predictions from our previously published Monte Carlo simulations. A detailed description of the sample preparation procedure is given as well ...

  20. Fiscal 2000 research achievement report on the pioneering research and development involving next-generation liquid crystal process base technologies; 2000 nendo jisedai ekisho process kiban gijutsu ni kakawaru sendo kenkyu kaihatsu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    For the enhancement of energy conservation in the liquid crystal display manufacturing process, activities are conducted in the three fields of (1) low temperature thin film fabrication technology, (2) zone-selective thin film growth technology, and (3) next-generation liquid crystal process base technology and comprehensive surveys. Conducted in field (1) are pioneering studies of low temperature high quality Si film fabrication by electromagnetic annealing, low temperature high quality thin film fabrication by EPA (electron plasma annealing), and low temperature normal pressure film fabrication. Conducted in field (2) are pioneering studies of zone-selective fabrication of high quality Si crystal film, high precision control of reforming (doping), and free pattern low resistance wiring fabrication. Conducted in field (3) are tentative fabrication, evaluation, and analysis of ultimate performance TFTs (thin film transistors) produced by the state-of-the-art purification enhancement technology; next-generation liquid crystal process; and surveys of functional thin film to be a novel material for substrates. In the pioneering study of low temperature high quality Si film fabrication by means of electromagnetic annealing, microwave annealing is studied as an energy efficient process to replace the currently favored ELA (excimer laser annealing) method, and then it is proved that the microwave annealing method is much higher in energy efficiency than the ELA method. (NEDO)

  1. PREFACE: 14th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS 2014)

    Science.gov (United States)

    2014-11-01

    It is our great pleasure to welcome you to the 14th International Conference on Micro- and Nano-Technology for Power Generation and Energy Conversion Applications, or PowerMEMS 2014, in Awaji Island, Japan. The aim of PowerMEM is to present the latest research results in the field of miniature, micro- and nano-scale technologies for power generation and energy conversion. The conference will also- give us the opportunity to exchange informations and new ideas in the field of Power MEMS/NEMS. The current status of the field of PowerMEMS spans the full spectrum from basic research to practical applications. We will enjoy valuable discussions not only from the viewpoint of academia but from commercial and industrial perspectives. In the conference, three invited speakers lead the technical program. We received 172 abstracts and after a careful reviewing process by the Technical Program Committee a total of 133 papers were selected for presentation. These have been organized into 16 Oral sessions in two parallel streams and two poster sessions including some late-news papers. The oral and regular poster papers are published by the Institute of Physics (IOP). We have also organized a PowerMEMS School in Kobe-Sannomiya contiguous to the main conference. This two-day school will cover various topics of energy harvesting. World leading experts will give invited lectures on their main topics. This is a new experiment to broaden the technology remit of our conference by organizing mini symposiums that aim to gather the latest research on the following topics by the organizers: Microscale Combustion, Wideband Vibration Energy Harvesting, RF Energy Transfer and Industrial Application. We hope this, and other activities will make PowerMEMS2014 a memorable success. One of the important programs in an international conference is the social program, and we prepare the PowerMEMS2014 banquet in the banquet room at the Westin Awaji Island Hotel. This will provide an opportunity to

  2. Generation of continuously tunable, 5-12 {mu}m radiation by difference frequency mixing of output waves of a KTP optical parametric oscillator in a ZnGeP{sub 2} crystal

    Energy Technology Data Exchange (ETDEWEB)

    Haidar, S [Research Institute of Electrical Communication (RIEC), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai-shi 980-8577 (Japan); Miyamoto, K [Research Institute of Electrical Communication (RIEC), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai-shi 980-8577 (Japan); Ito, H [Research Institute of Electrical Communication (RIEC), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai-shi 980-8577 (Japan)

    2004-12-07

    Signal and idlers waves obtained from a Nd : YAG laser pumped KTP optical parametric oscillator (OPO) are difference frequency mixed in a ZnGeP{sub 2} (ZGP) crystal to generate radiation in the mid-infrared. The KTP OPO is operated in the type-II phase matching mode, and the extraordinary and ordinary waves are tunable from 1.76 {mu}m to 2.36 {mu}m and from 2.61 {mu}m to 1.90 {mu}m, respectively. The orthogonally polarized waves are difference frequency mixed in a ZGP crystal to generate mid-IR radiation tunable from 5 to 12 {mu}m.

  3. 5.5 W of Diffraction-Limited Green Light Generated by SFG of Tapered Diode Lasers in a Cascade of Nonlinear Crystals

    DEFF Research Database (Denmark)

    Hansen, Anders Kragh; Jensen, Ole Bjarlin; Andersen, Peter Eskil

    2015-01-01

    Diode-based high power visible lasers are perfect pump sources for, e.g., titaniumsapphire lasers. The combination of favorable scaling laws in both SFG and cascading of nonlinear crystals allows access to unprecedented powers in diode-based systems.......Diode-based high power visible lasers are perfect pump sources for, e.g., titaniumsapphire lasers. The combination of favorable scaling laws in both SFG and cascading of nonlinear crystals allows access to unprecedented powers in diode-based systems....

  4. ADRIA: A summary of different tools for motor and generator field service activities in the international market

    International Nuclear Information System (INIS)

    Krell, M.; Wuehler, H.

    2012-01-01

    AREVA Drive In Application (ADRIA) – is an innovative program for use at sites all over the world. ADRIA is a full package for medium voltage motor and generator services growth in the long-term, which presents a wide range of applications for nuclear- , thermal- , renewable hydro power plants and all industrial plants. ADRIA support our customers with an optimized product in MV motor management systems e.g., dismantling, maintenance, repair, tools, containers with full equipped working tools or measure equipment. Are you planning to open a site? You will need special equipment and very special diagnostic methods for electrical analysis for preventive maintenance scheduling and planning; special support from experts, ADRIA is a good, unitized, and flexible solution which can be adapted to different customer requirements. • Technical modules show low service and maintenance costs due to the life time of electrical machines. • Measurement module – a solution for the actual condition of the MV motors and generators (vibration, partial discharge, infrared technology, cable analysis, motor – current – analysis) • Documentation module – for all projects in joining with quality management • Tools module – support for all activities in service (working tools, office / store containers) • Man power module – for all service in the field (Experts with world wide experience) • For pre-maintenance we use, for example, infrared technology. Experts monitor different cycles and find out which parts are creating problems. The maintenance strategy will be clear, shorter and more effective for the next outage. ADRIA offers great advantages for the global maintenance market providing time, efficiency and preventive scheduling, efforts and saving of costs. This new technology method has been successfully applied in various motor refurbishment projects in German, Spain or Brazil nuclear power plants since 2010. Further follow-up orders in German and

  5. Broadband dynamic phase matching of high-order harmonic generation by a high-peak-power soliton pump field in a gas-filled hollow photonic-crystal fiber.

    Science.gov (United States)

    Serebryannikov, Evgenii E; von der Linde, Dietrich; Zheltikov, Aleksei M

    2008-05-01

    Hollow-core photonic-crystal fibers are shown to enable dynamically phase-matched high-order harmonic generation by a gigawatt soliton pump field. With a careful design of the waveguide structure and an appropriate choice of input-pulse and gas parameters, a remarkably broadband phase matching can be achieved for a soliton pump field and a large group of optical harmonics in the soft-x-ray-extreme-ultraviolet spectral range.

  6. Internal vibrations in molecular crystals

    International Nuclear Information System (INIS)

    Howard, J.

    1984-01-01

    Recent developments in the understanding of the relative intensities of INS bands (polycrystalline samples) are described together with the observation of a fundamental transition at ca 380 MeV (C-H stretching mode) uncontaminated by overtone or combination bands. Recent work (>100 MeV) on strongly hydrogen bonded complexes (CrOHO and MFHF - ), which have high energy modes exhibiting significant dispersion, is also discussed

  7. The mechanism behind internally generated centennial-to-millennial scale climate variability in an earth system model of intermediate complexity

    Directory of Open Access Journals (Sweden)

    T. Friedrich

    2010-08-01

    Full Text Available The mechanism triggering centennial-to-millennial-scale variability of the Atlantic Meridional Overturning Circulation (AMOC in the earth system model of intermediate complexity LOVECLIM is investigated. It is found that for several climate boundary conditions such as low obliquity values (~22.1° or LGM-albedo, internally generated centennial-to-millennial-scale variability occurs in the North Atlantic region. Stochastic excitations of the density-driven overturning circulation in the Nordic Seas can create regional sea-ice anomalies and a subsequent reorganization of the atmospheric circulation. The resulting remote atmospheric anomalies over the Hudson Bay can release freshwater pulses into the Labrador Sea and significantly increase snow fall in this region leading to a subsequent reduction of convective activity. The millennial-scale AMOC oscillations disappear if LGM bathymetry (with closed Hudson Bay is prescribed or if freshwater pulses are suppressed artificially. Furthermore, our study documents the process of the AMOC recovery as well as the global marine and terrestrial carbon cycle response to centennial-to-millennial-scale AMOC variability.

  8. Crystals in crystals

    DEFF Research Database (Denmark)

    Christensen, Claus H.; Schmidt, I.; Carlsson, A.

    2005-01-01

    A major factor governing the performance of catalytically active particles supported on a zeolite carrier is the degree of dispersion. It is shown that the introduction of noncrystallographic mesopores into zeolite single crystals (silicalite-1, ZSM-5) may increase the degree of particle dispersion....... As representative examples, a metal (Pt), an alloy (PtSn), and a metal carbide (beta-Mo2C) were supported on conventional and mesoporous zeolite carriers, respectively, and the degree of particle dispersion was compared by TEM imaging. On conventional zeolites, the supported material aggregated on the outer surface...

  9. Virtual Crystallizer

    Energy Technology Data Exchange (ETDEWEB)

    Land, T A; Dylla-Spears, R; Thorsness, C B

    2006-08-29

    Large dihydrogen phosphate (KDP) crystals are grown in large crystallizers to provide raw material for the manufacture of optical components for large laser systems. It is a challenge to grow crystal with sufficient mass and geometric properties to allow large optical plates to be cut from them. In addition, KDP has long been the canonical solution crystal for study of growth processes. To assist in the production of the crystals and the understanding of crystal growth phenomena, analysis of growth habits of large KDP crystals has been studied, small scale kinetic experiments have been performed, mass transfer rates in model systems have been measured, and computational-fluid-mechanics tools have been used to develop an engineering model of the crystal growth process. The model has been tested by looking at its ability to simulate the growth of nine KDP boules that all weighed more than 200 kg.

  10. single crystals

    Indian Academy of Sciences (India)

    2018-05-18

    May 18, 2018 ... Abstract. 4-Nitrobenzoic acid (4-NBA) single crystals were studied for their linear and nonlinear optical ... studies on the proper growth, linear and nonlinear optical ..... between the optic axes and optic sign of the biaxial crystal.

  11. Crystal Systems.

    Science.gov (United States)

    Schomaker, Verner; Lingafelter, E. C.

    1985-01-01

    Discusses characteristics of crystal systems, comparing (in table format) crystal systems with lattice types, number of restrictions, nature of the restrictions, and other lattices that can accidently show the same metrical symmetry. (JN)

  12. Generation of mariner-based transposon insertion mutant library of Bacillus sphaericus 2297 and investigation of genes involved in sporulation and mosquito-larvicidal crystal protein synthesis.

    Science.gov (United States)

    Wu, Yiming; Hu, Xiaomin; Ge, Yong; Zheng, Dasheng; Yuan, Zhiming

    2012-05-01

    Bacillus sphaericus has been used with great success in mosquito control programs worldwide. Under conditions of nutrient limitation, it undergoes sporulation via a series of well defined morphological stages. However, only a small number of genes involved in sporulation have been identified. To identify genes associated with sporulation, and to understand the relationship between sporulation and crystal protein synthesis, a random mariner-based transposon insertion mutant library of B. sphaericus strain 2297 was constructed and seven sporulation-defective mutants were selected. Sequencing of the DNA flanking of the transposon insertion identified several genes involved in sporulation. The morphologies of mutants were determined by electron microscopy and synthesis of crystal proteins was analyzed by SDS-PAGE and Western blot. Four mutants blocked at early stages of sporulation failed to produce crystal proteins and had lower larvicidal activity. However, the other three mutants were blocked at later stages and were able to form crystal proteins, and the larvicidal activity was similar to wild type. These results indicated that crystal protein synthesis in B. sphaericus is dependent on sporulation initiation. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  13. Observation of sum-frequency-generation-induced cascaded four-wave mixing using two crossing femtosecond laser pulses in a 0.1 mm beta-barium-borate crystal.

    Science.gov (United States)

    Liu, Weimin; Zhu, Liangdong; Fang, Chong

    2012-09-15

    We demonstrate the simultaneous generation of multicolor femtosecond laser pulses spanning the wavelength range from UV to near IR in a 0.1 mm Type I beta-barium borate crystal from 800 nm fundamental and weak IR super-continuum white light (SCWL) pulses. The multicolor broadband laser pulses observed are attributed to two concomitant cascaded four-wave mixing (CFWM) processes as corroborated by calculation: (1) directly from the two incident laser pulses; (2) by the sum-frequency generation (SFG) induced CFWM process (SFGFWM). The latter signal arises from the interaction between the frequency-doubled fundamental pulse (400 nm) and the SFG pulse generated in between the fundamental and IR-SCWL pulses. The versatility and simplicity of this spatially dispersed multicolor self-compressed laser pulse generation offer compact and attractive methods to conduct femtosecond stimulated Raman spectroscopy and time-resolved multicolor spectroscopy.

  14. Neodymium-140 DOTA-LM3: Evaluation of an In Vivo Generator for PET with a Non-Internalizing Vector

    Science.gov (United States)

    Severin, Gregory W.; Kristensen, Lotte K.; Nielsen, Carsten H.; Fonslet, Jesper; Jensen, Andreas I.; Frellsen, Anders F.; Jensen, K. M.; Elema, Dennis R.; Maecke, Helmut; Kjær, Andreas; Johnston, Karl; Köster, Ulli

    2017-01-01

    140Nd (t1/2 = 3.4 days), owing to its short-lived positron emitting daughter 140Pr (t1/2 = 3.4 min), has promise as an in vivo generator for positron emission tomography (PET). However, the electron capture decay of 140Nd is chemically disruptive to macrocycle-based radiolabeling, meaning that an in vivo redistribution of the daughter 140Pr is expected before positron emission. The purpose of this study was to determine how the delayed positron from the de-labeled 140Pr affects preclinical imaging with 140Nd. To explore the effect, 140Nd was produced at CERN-ISOLDE, reacted with the somatostatin analogue, DOTA-LM3 (1,4,7,10- tetraazacyclododecane, 1,4,7- tri acetic acid, 10- acetamide N - p-Cl-Phecyclo(d-Cys-Tyr-d-4-amino-Phe(carbamoyl)-Lys-Thr-Cys)d-Tyr-NH2) and injected into H727 xenograft bearing mice. Comparative pre- and post-mortem PET imaging at 16 h postinjection was used to quantify the in vivo redistribution of 140Pr following 140Nd decay. The somatostatin receptor-positive pancreas exhibited the highest tissue accumulation of 140Nd-DOTA-LM3 (13% ID/g at 16 h) coupled with the largest observed redistribution rate, where 56 ± 7% (n = 4, mean ± SD) of the in situ produced 140Pr washed out of the pancreas before decay. Contrastingly, the liver, spleen, and lungs acted as strong sink organs for free 140Pr3+. Based upon these results, we conclude that 140Nd imaging with a non-internalizing vector convolutes the biodistribution of the tracer with the accumulation pattern of free 140Pr. This redistribution phenomenon may show promise as a probe of the cellular interaction with the vector, such as in determining tissue dependent internalization behavior. PMID:28748183

  15. Neodymium-140 DOTA-LM3: Evaluation of an In Vivo Generator for PET with a Non-Internalizing Vector

    Directory of Open Access Journals (Sweden)

    Gregory W. Severin

    2017-07-01

    Full Text Available 140Nd (t1/2 = 3.4 days, owing to its short-lived positron emitting daughter 140Pr (t1/2 = 3.4 min, has promise as an in vivo generator for positron emission tomography (PET. However, the electron capture decay of 140Nd is chemically disruptive to macrocycle-based radiolabeling, meaning that an in vivo redistribution of the daughter 140Pr is expected before positron emission. The purpose of this study was to determine how the delayed positron from the de-labeled 140Pr affects preclinical imaging with 140Nd. To explore the effect, 140Nd was produced at CERN-ISOLDE, reacted with the somatostatin analogue, DOTA-LM3 (1,4,7,10- tetraazacyclododecane, 1,4,7- tri acetic acid, 10- acetamide N - p-Cl-Phecyclo(d-Cys-Tyr-d-4-amino-Phe(carbamoyl-Lys-Thr-Cysd-Tyr-NH2 and injected into H727 xenograft bearing mice. Comparative pre- and post-mortem PET imaging at 16 h postinjection was used to quantify the in vivo redistribution of 140Pr following 140Nd decay. The somatostatin receptor-positive pancreas exhibited the highest tissue accumulation of 140Nd-DOTA-LM3 (13% ID/g at 16 h coupled with the largest observed redistribution rate, where 56 ± 7% (n = 4, mean ± SD of the in situ produced 140Pr washed out of the pancreas before decay. Contrastingly, the liver, spleen, and lungs acted as strong sink organs for free 140Pr3+. Based upon these results, we conclude that 140Nd imaging with a non-internalizing vector convolutes the biodistribution of the tracer with the accumulation pattern of free 140Pr. This redistribution phenomenon may show promise as a probe of the cellular interaction with the vector, such as in determining tissue dependent internalization behavior.

  16. Exact and near backscattering measurements of the linear depolarisation ratio of various ice crystal habits generated in a laboratory cloud chamber

    Science.gov (United States)

    Smith, Helen R.; Connolly, Paul J.; Webb, Ann R.; Baran, Anthony J.

    2016-07-01

    Ice clouds were generated in the Manchester Ice Cloud Chamber (MICC), and the backscattering linear depolarisation ratio, δ, was measured for a variety of habits. To create an assortment of particle morphologies, the humidity in the chamber was varied throughout each experiment, resulting in a range of habits from the pristine to the complex. This technique was repeated at three temperatures: -7 °C, -15 °C and -30 °C, in order to produce both solid and hollow columns, plates, sectored plates and dendrites. A linearly polarised 532 nm continuous wave diode laser was directed through a section of the cloud using a non-polarising 50:50 beam splitter. Measurements of the scattered light were taken at 178°, 179° and 180°, using a Glan-Taylor prism to separate the co- and cross-polarised components. The intensities of these components were measured using two amplified photodetectors and the ratio of the cross- to co-polarised intensities was measured to find the linear depolarisation ratio. In general, it was found that Ray Tracing over-predicts the linear depolarisation ratio. However, by creating more accurate particle models which better represent the internal structure of ice particles, discrepancies between measured and modelled results (based on Ray Tracing) were reduced.

  17. Crystal Ball contributions to the 9th international workshop on photon-photon collisions, La Jolla, 23-26 March 1992

    International Nuclear Information System (INIS)

    Bienlein, J.K.

    1992-06-01

    This report contains two articles concerning new Crystal Ball data on resonance formation by γγ collisions and the representation of such results by helicity amplitudes. See hints under the relevant topics. (HSI)

  18. The 13th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS 2013)

    Science.gov (United States)

    Mitcheson, Paul; Beeby, Steve

    2013-12-01

    It is a pleasure to welcome you to The Royal Society in London and the 13th International Conference on Micro- and Nano-Technology for Power Generation and Energy Conversion Applications, or PowerMEMS 2013. The objective of PowerMEMS 2013 is to catalyse innovation in miniature, micro- and nano-scale technologies for power generation and energy conversion. The conference aims to stimulate the exchange of insights and information, and the development of new ideas in the Power MEMS/NEMS field as well as at the meso-scale. It will allow the attendees to interact and network within our multidisciplinary community that includes professionals from many branches of science and engineering. The technical program is led by four invited speakers covering inductive power transfer, chip scale power sources, thermal energy harvesting and implantable biofuel cells. We received 177 abstracts and following a careful reviewing process by the Technical Program Committee a total of 137 papers were selected for presentation. These have been organised into 16 oral sessions in two parallel streams and two poster sessions that have been augmented by 10 late news papers. The oral and regular poster papers are, for the first time, being published by the Institute of Physics. We have made every effort to make PowerMEMS 2013 the busiest yet and have included for the first time the PowerMEMS School. This two-day school held at Imperial College London covered a wide range of power-MEMS topics including technologies for power generation, power transmission, energy storage, power electronics interfaces and metrology. Registrations for the School exceeded our expectations and it was full by early November. We hope this, and other activities such as the Discussion Panel and the inclusion of late news papers, will make PowerMEMS 2013 a memorable success. We have also reached out to new communities, such as those working in wireless power transfer and RF harvesting to broaden the technology remit of

  19. Generation of actinide colloids and their sorption on rocks. A study on colloids in an ISTC (International Science and Technology Center) project

    International Nuclear Information System (INIS)

    Fujiwara, Ai

    2005-01-01

    Results of experimental studies on generation of colloids and their sorption on rocks conducted in the ISTC (International Science and Technology Center) project No.1326 are presented, as well as a brief introduction of the project and a planned new project on colloidal migration near the Karachai Lake, Russia. (author)

  20. Monomial Crystals and Partition Crystals

    Science.gov (United States)

    Tingley, Peter

    2010-04-01

    Recently Fayers introduced a large family of combinatorial realizations of the fundamental crystal B(Λ0) for ^sln, where the vertices are indexed by certain partitions. He showed that special cases of this construction agree with the Misra-Miwa realization and with Berg's ladder crystal. Here we show that another special case is naturally isomorphic to a realization using Nakajima's monomial crystal.

  1. Disorder in Protein Crystals.

    Science.gov (United States)

    Clarage, James Braun, II

    1990-01-01

    Methods have been developed for analyzing the diffuse x-ray scattering in the halos about a crystal's Bragg reflections as a means of determining correlations in atomic displacements in protein crystals. The diffuse intensity distribution for rhombohedral insulin, tetragonal lysozyme, and triclinic lysozyme crystals was best simulated in terms of exponential displacement correlation functions. About 90% of the disorder can be accounted for by internal movements correlated with a decay distance of about 6A; the remaining 10% corresponds to intermolecular movements that decay in a distance the order of size of the protein molecule. The results demonstrate that protein crystals fit into neither the Einstein nor the Debye paradigms for thermally fluctuating crystalline solids. Unlike the Einstein model, there are correlations in the atomic displacements, but these correlations decay more steeply with distance than predicted by the Debye-Waller model for an elastic solid. The observed displacement correlations are liquid -like in the sense that they decay exponentially with the distance between atoms, just as positional correlations in a liquid. This liquid-like disorder is similar to the disorder observed in 2-D crystals of polystyrene latex spheres, and similar systems where repulsive interactions dominate; hence, these colloidal crystals appear to provide a better analogy for the dynamics of protein crystals than perfectly elastic lattices.

  2. The Role of Subsidiaries in Emerging Markets in Generating Competitive Advantages for Foreign Multinationals: the case of the Brazilian subsidiary of Clarks International

    Directory of Open Access Journals (Sweden)

    Marcelo André Machado

    2014-07-01

    Full Text Available The relationship between a multinational and its subsidiaries abroad, according to many studies, is crucial for generating competitive advantages. Therefore, this study aimed to understand the relationship between a shoe company, Clarks International, and its Brazilian subsidiary with an emphasis on generating advantages to the multinational headquarters. Through a single case study, the subsidiary’s capacity for knowledge generation and diffusion was identified, as well as its level of autonomy in relation to the English headquarters. Data analysis indicated that the Brazilian subsidiary generated specific competitive advantages for the foreign multinational due to its close relationship with local suppliers in Brazil and due to its staff’s expertise in developing high quality shoes. It was perceived that the growth of subsidiary autonomy was related to the growth of specific advantages generated for the multinational.

  3. 16th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS 2016)

    International Nuclear Information System (INIS)

    2016-01-01

    It is our great pleasure to welcome you to PowerMEMS’16 - the 16th International Conference on Micro- and Nano-Technology for Power Generation and Energy Conversion Applications - in Paris at the UIC Espace Congrès, a few meters away from the Eiffel Tower. The objective of the PowerMEMS conference is to catalyse innovation in micro- and nano- scale technologies for the energy domain. The scope of the meeting ranges from basic principles, to materials and fabrication, to devices and systems, to applications. The many applications of Power MEMS concern the harvesting, storage, conversion and conditioning of energy, to integrated systems that manage these processes, to actuation, pumping, and propulsion. Our Conference aims to stimulate the exchange of insights and information, as well as the development of new ideas, in the Power MEMS field. Our goal is to allow the attendees to interact and network within our multidisciplinary community that includes professionals from many branches of science and engineering, as well as energy, policy, and entrepreneurial specialists interested in the commercialization of Power MEMS technologies. This year's technical program is highlighted by four plenary talks from prominent experts on M/NEMS for ultra-low power in electronics, advanced nanomaterial for solar cells and thermal transistor. The contributed program received 159 abstract submissions this year. After careful review by the 33-members of the Technical Program Committee, a total of 123 papers will be presented. The 40 contributed oral presentations are arranged in two parallel sessions. The 83 posters are arranged in a ''two-in-one'' poster session in which the poster session time is divided in two; half the posters will be presented during each half-session, allowing the poster presenters to also browse the posters during the poster session. Posters will remain up during the meeting, so please feel free to peruse them at your leisure. The

  4. Progress in KNbO/sub 3/ crystal growth and its use in second harmonic generation with a cw-Ga/sub 1-x/Al/sub x/As laser

    International Nuclear Information System (INIS)

    Looser, H.; Gunter, P.; Wu, X.; Arend, H.

    1987-01-01

    KNbO/sub 3/ is especially well suited for second harmonic generation of dye and Ga/sub 1-x/Al/sub x/As lasers with wavelength λ ≅ 860 nm. Using its high nonlinear optical coefficient, d/sub 32/ = 20.3 pm/V, noncritical type l phase matching is possible for fundamental wavelengths of 840-990 nm with crystal temperatures between -40 and 210 0 C. With a pulsed laser diode the authors previously reported 0.35-mW second harmonic peak power from 0.8-W fundamental frequency distributed among eight modes. In this paper, this work is extended to high-power monomode cw laser diodes. Other device parameters such as temperature stability and influence of the crystal homogeneity on the efficiency are discussed

  5. Nuclear systems of the future: international forum generation 4 and research and development projects at the Cea; Systemes nucleaires du futur: forum international generation 4 et projets de R et D du CEA

    Energy Technology Data Exchange (ETDEWEB)

    Carre, F

    2003-07-01

    To advance nuclear energy to meet future energy needs, ten countries have agreed to develop a future generation of nuclear energy systems, known as Generation 4. A technology road map to guide the Generation 4 effort was begun. This document presents the goals for these nuclear systems and the research programs of the Cea on the gas technology, GT-MHR, VHTR and GFR and the other systems as sodium Fast Neutron reactors, supercritical water and space nuclear. (A.L.B.)

  6. WORKSHOP: Scintillating crystals

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1992-12-15

    Scintillating crystals are one of the big spinoff success stories of particle physics, and from 22-26 September an international workshop in Chamonix in the French Alps looked at the increasing role of these materials in pure and applied science and in industry.

  7. WORKSHOP: Scintillating crystals

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Scintillating crystals are one of the big spinoff success stories of particle physics, and from 22-26 September an international workshop in Chamonix in the French Alps looked at the increasing role of these materials in pure and applied science and in industry

  8. Re-Thinking Internationalization as Social Curriculum for Generative Supervision: Letters from the International Community of Scholars

    Science.gov (United States)

    Hellstén, Meeri; Ucker Perotto, Lilian

    2018-01-01

    This paper concerns research issues on curriculum, pedagogy and the creative use of method in international higher education. It is motivated by the witnessing of a recent shifting in consensus within the global research communities on international education, towards curriculum renewal of shared knowledge within the field. The article enters into…

  9. Post-Flight Microbial Analysis of Samples from the International Space Station Water Recovery System and Oxygen Generation System

    Science.gov (United States)

    Birmele, Michele N.

    2011-01-01

    The Regenerative, Environmental Control and Life Support System (ECLSS) on the International Space Station (ISS) includes the the Water Recovery System (WRS) and the Oxygen Generation System (OGS). The WRS consists of a Urine Processor Assembly (UPA) and Water Processor Assembly (WPA). This report describes microbial characterization of wastewater and surface samples collected from the WRS and OGS subsystems, returned to KSC, JSC, and MSFC on consecutive shuttle flights (STS-129 and STS-130) in 2009-10. STS-129 returned two filters that contained fluid samples from the WPA Waste Tank Orbital Recovery Unit (ORU), one from the waste tank and the other from the ISS humidity condensate. Direct count by microscopic enumeration revealed 8.38 x 104 cells per mL in the humidity condensate sample, but none of those cells were recoverable on solid agar media. In contrast, 3.32 x lOs cells per mL were measured from a surface swab of the WRS waste tank, including viable bacteria and fungi recovered after S12 days of incubation on solid agar media. Based on rDNA sequencing and phenotypic characterization, a fungus recovered from the filter was determined to be Lecythophora mutabilis. The bacterial isolate was identified by rDNA sequence data to be Methylobacterium radiotolerans. Additional UPA subsystem samples were returned on STS-130 for analysis. Both liquid and solid samples were collected from the Russian urine container (EDV), Distillation Assembly (DA) and Recycle Filter Tank Assembly (RFTA) for post-flight analysis. The bacterium Pseudomonas aeruginosa and fungus Chaetomium brasiliense were isolated from the EDV samples. No viable bacteria or fungi were recovered from RFTA brine samples (N= 6), but multiple samples (N = 11) from the DA and RFTA were found to contain fungal and bacterial cells. Many recovered cells have been identified to genus by rDNA sequencing and carbon source utilization profiling (BiOLOG Gen III). The presence of viable bacteria and fungi from WRS

  10. Heat transfer and thermodynamic performance of convective–radiative cooling double layer walls with temperature-dependent thermal conductivity and internal heat generation

    International Nuclear Information System (INIS)

    Torabi, Mohsen; Zhang, Kaili

    2015-01-01

    Highlights: • First and second laws of thermodynamics have been investigated in a composite wall. • Convective–radiative heat transfer is assumed on both surfaces. • Optimum interface location is calculated to minimize the total entropy generation rate. • Thermal conductivities ratio has great effects on the temperature and entropy generation. - Abstract: Composite geometries have numerous applications in industry and scientific researches. This work investigates the temperature distribution, and local and total entropy generation rates within two-layer composite walls using conjugate convection and radiation boundary conditions. Thermal conductivities of the materials of walls are assumed temperature-dependent. Temperature-dependent internal heat generations are also incorporated into the modeling. The differential transformation method (DTM) is used as an analytical technique to tackle the highly nonlinear system of ordinary differential equations. Thereafter, the local and total entropy generation rates are calculated using the DTM formulated temperature distribution. An exact analytical solution, for the temperature-independent model without radiation effect, is also derived. The correctness and accuracy of the DTM solution are checked against the exact solution. After verification, effects of thermophysical parameters such as location of the interface, convection–conduction parameters, radiation–conduction parameters, and internal heat generations, on the temperature distribution, and both local and total entropy generation rates are examined. To deliver the minimum total entropy generation rate, optimum values for some parameters are also found. Since composite walls are widely used in many fields, the abovementioned investigation is a beneficial tool for many engineering industries and scientific fields to minimize the entropy generation, which is the exergy destruction, of the system

  11. RNA Crystallization

    Science.gov (United States)

    Golden, Barbara L.; Kundrot, Craig E.

    2003-01-01

    RNA molecules may be crystallized using variations of the methods developed for protein crystallography. As the technology has become available to syntheisize and purify RNA molecules in the quantities and with the quality that is required for crystallography, the field of RNA structure has exploded. The first consideration when crystallizing an RNA is the sequence, which may be varied in a rational way to enhance crystallizability or prevent formation of alternate structures. Once a sequence has been designed, the RNA may be synthesized chemically by solid-state synthesis, or it may be produced enzymatically using RNA polymerase and an appropriate DNA template. Purification of milligram quantities of RNA can be accomplished by HPLC or gel electrophoresis. As with proteins, crystallization of RNA is usually accomplished by vapor diffusion techniques. There are several considerations that are either unique to RNA crystallization or more important for RNA crystallization. Techniques for design, synthesis, purification, and crystallization of RNAs will be reviewed here.

  12. FY 1977 Annual report on Sunshine Project results. Research and development of photovoltaic power generation systems (Research and development of vertically drawn ribbon crystals of silicon); 1977 nendo taiyoko hatsuden system no kenkyu kaihatsu seika hokokusho. Silicon tatehiki ribon kessho no kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1978-03-31

    This project is aimed at establishment of ribbon crystal production techniques and development of photovoltaic power generation systems incorporating the ribbon crystals, in order to greatly reduce cost of photovoltaic power generation systems. The research efforts in this fiscal year is focused on development of the techniques for continuously growing the ribbons, to attain the above goal by accelerating growth of the ribbon crystals in unit time and clarifying, in the early stage, the problems to be solved before commercializing the ribbon crystals for the future solar cells. The major research results are (1) development of the method for vertically drawing ribbon crystals of silicon, and (2) analysis of the vertically drawn ribbon crystals of silicon. For the item (1), the technological development efforts are focused on continuously drawing mechanisms and furnace for continuous drawing, with the structural studies as the center for the former and solution of heat-related problems for the latter, which eventually lead to development of a 800 mm long ribbon crystal passing over the roll. For the item (2), the crystal structure is analyzed by the electron channeling pattern method. The results suggest that use of a p-type substrate can improve average efficiency of the ribbon crystal type solar cell. (NEDO)

  13. ICCG-10: International Conference on Crystal Growth (10th) Held in San Diego, California on August 16-21, 1992. Oral Presentation Abstracts.

    Science.gov (United States)

    1992-10-01

    D.J nt1 , A. L FrlPP. W. J. Debnam. Jir., a. A. Woodell and W. L Kw. S. A. Payne. W. F. Kruplke. L D. DeLoach. L K. Smith and J. R. Nerayanan B. Tassano...Inst. of Blo. Molec & Cell CNRS. France 9:30 Morphological Properties of CV0 AIN Films 9:30 * Growth and Dissolution Kinetics of Lysozyme Crystals R...Huntsvile. USA Physiochemie des Materltnc. France 10:00 COFFEE BREAK 10:00 Nucleation Phenomena in Crystallization of Satellite Tobacco Mosi Virus

  14. Nuclear systems of the future: international forum generation 4 and research and development projects at the Cea

    International Nuclear Information System (INIS)

    Carre, F.

    2003-01-01

    To advance nuclear energy to meet future energy needs, ten countries have agreed to develop a future generation of nuclear energy systems, known as Generation 4. A technology road map to guide the Generation 4 effort was begun. This document presents the goals for these nuclear systems and the research programs of the Cea on the gas technology, GT-MHR, VHTR and GFR and the other systems as sodium Fast Neutron reactors, supercritical water and space nuclear. (A.L.B.)

  15. The Preferred Work Paradigm for Generation Y in the Hotel Industry: A Case Study of the International Tourism and Hospitality International Programme, Thailand

    Science.gov (United States)

    Dhevabanchachai, Nate-tra; Muangasame, Kaewta

    2013-01-01

    It is well known that hospitality work is physically demanding and involves mental stress and, at times, an uncompetitive compensation package. This has resulted in a high employee turnover rate in recent years. Staff retention is thus a challenge, especially for employees belonging to Generation Y (Gen Y). The situation in Thailand is not…

  16. Carbon emission offsets for aviation-generated emissions due to international travel to and from New Zealand

    International Nuclear Information System (INIS)

    Smith, Inga J.; Rodger, Craig J.

    2009-01-01

    International air transport emissions are not subject to liability under the Kyoto Protocol. However, pressure is mounting globally for international aviation to be included in post-Kyoto arrangements. In the absence of international collective action, a number of so-called carbon offsetting schemes have emerged that allow individual travellers and companies to compensate for their international air travel emissions. These schemes offer technological solutions, such as planting sink forests to sequester emissions. To consider the implications of future collective action, this paper presents a case study assessment of the physical feasibility of five schemes for all short duration journeys to and from New Zealand. This is the first comprehensive national-level case study assessment of competing offsetting options for international aviation emissions in the peer-reviewed literature. The CO 2 -e emissions produced by the air travel of international visitors to New Zealand, and for New Zealand residents travelling overseas, is calculated in this paper to be 7893 and 3948 Gg, respectively, in 2005. It is then shown that no single offsetting scheme targeted inside the country appears physically and/or politically realistic. This indicates the sheer size of these emissions, and the challenge that the international community faces for collective action on this matter. (author)

  17. Generation of 320 mW at 10.20 μm based on CdSe long-wave infrared crystal

    Science.gov (United States)

    Wang, Jian; Yuan, Ligang; Zhang, Yingwu; Chen, Guo; Cheng, Hongjuan; Gao, Yanzhao

    2018-06-01

    CdSe single crystal, with the sizes of ∼54 mm in diameter and ∼25 mm in length, was grown by a high pressure vertical gradient freeze (HPVGF) technique using (0 0 1)-oriented seed. The CdSe crystal was characterized with transmission spectrophotometer. The transmission spectra showed that the infrared transmission was above 68% and the mean absorption coefficient was 0.041 cm-1 in the range of 2.5-20 μm. Using fabricated CdSe crystal with the dimensions of 6 mm × 10 mm × 44 mm, we demonstrated an optical parametric oscillator (OPO) pumped by a 2.05 μm Ho:YLF laser at a pulse repetition frequency of 5 kHz. Up to 320 mW output was obtained at the idler wavelength of 10.20 μm with a pump power of 18.06 W. 320 mW at 10.20 μm, to our knowledge, was the highest power obtained with a 2.05 μm laser-pumped CdSe OPO.

  18. Crystallization mechanisms of acicular crystals

    Science.gov (United States)

    Puel, François; Verdurand, Elodie; Taulelle, Pascal; Bebon, Christine; Colson, Didier; Klein, Jean-Paul; Veesler, Stéphane

    2008-01-01

    In this contribution, we present an experimental investigation of the growth of four different organic molecules produced at industrial scale with a view to understand the crystallization mechanism of acicular or needle-like crystals. For all organic crystals studied in this article, layer-by-layer growth of the lateral faces is very slow and clear, as soon as the supersaturation is high enough, there is competition between growth and surface-activated secondary nucleation. This gives rise to pseudo-twinned crystals composed of several needle individuals aligned along a crystallographic axis; this is explained by regular over- and inter-growths as in the case of twinning. And when supersaturation is even higher, nucleation is fast and random. In an industrial continuous crystallization, the rapid growth of needle-like crystals is to be avoided as it leads to fragile crystals or needles, which can be partly broken or totally detached from the parent crystals especially along structural anisotropic axis corresponding to weaker chemical bonds, thus leading to slower growing faces. When an activated mechanism is involved such as a secondary surface nucleation, it is no longer possible to obtain a steady state. Therefore, the crystal number, size and habit vary significantly with time, leading to troubles in the downstream processing operations and to modifications of the final solid-specific properties. These results provide valuable information on the unique crystallization mechanisms of acicular crystals, and show that it is important to know these threshold and critical values when running a crystallizer in order to obtain easy-to-handle crystals.

  19. An Internationally Comparative Study of Immigration and Adolescent Emotional and Behavioral Problems : Effects of Generation and Gender

    NARCIS (Netherlands)

    Stevens, Gonneke W J M; Walsh, Sophie D; Huijts, Tim; Maes, Marlies; Madsen, Katrine Rich; Cavallo, Franco; Molcho, Michal

    2015-01-01

    PURPOSE: Although the potential consequences of immigration for adolescent problem behaviors have been addressed in many former studies, internationally comparative research is scarce. This study investigated the impact of immigration on four indicators of adolescents' emotional and behavioral

  20. Principles of crystallization, and methods of single crystal growth

    International Nuclear Information System (INIS)

    Chacra, T.

    2010-01-01

    Most of single crystals (monocrystals), have distinguished optical, electrical, or magnetic properties, which make from single crystals, key elements in most of technical modern devices, as they may be used as lenses, Prisms, or grating sin optical devises, or Filters in X-Ray and spectrographic devices, or conductors and semiconductors in electronic, and computer industries. Furthermore, Single crystals are used in transducer devices. Moreover, they are indispensable elements in Laser and Maser emission technology.Crystal Growth Technology (CGT), has started, and developed in the international Universities and scientific institutions, aiming at some of single crystals, which may have significant properties and industrial applications, that can attract the attention of international crystal growth centers, to adopt the industrial production and marketing of such crystals. Unfortunately, Arab universities generally, and Syrian universities specifically, do not give even the minimum interest, to this field of Science.The purpose of this work is to attract the attention of Crystallographers, Physicists and Chemists in the Arab universities and research centers to the importance of crystal growth, and to work on, in the first stage to establish simple, uncomplicated laboratories for the growth of single crystal. Such laboratories can be supplied with equipment, which are partly available or can be manufactured in the local market. Many references (Articles, Papers, Diagrams, etc..) has been studied, to conclude the most important theoretical principles of Phase transitions,especially of crystallization. The conclusions of this study, are summarized in three Principles; Thermodynamic-, Morphologic-, and Kinetic-Principles. The study is completed by a brief description of the main single crystal growth methods with sketches, of equipment used in each method, which can be considered as primary designs for the equipment, of a new crystal growth laboratory. (author)

  1. Multi-boiling Heat Transfer Analysis of a Convective Straight Fin with Temperature-Dependent Thermal Properties and Internal Heat Generation

    Directory of Open Access Journals (Sweden)

    Gbeminiyi Sobamowo

    2017-10-01

    Full Text Available In this study, by using the finite volume method, the heat transfer in a convective straight fin with temperature-dependent thermal properties and an internal heat generation under multi-boiling heat transfer modes are analyzed. In this regard, the local heat transfer coefficient is considered to vary within a power-law function of temperature. In the present study, the coexistence of all the boiling modes is taken into consideration. The developed heat transfer models and the corresponding numerical solutions are used to investigate the effects of various thermo-geometric parameters on the thermal performance of the longitudinal rectangular fin. The results shows that the fin temperature distribution, the total heat transfer, and the fin efficiency are significantly affected by the thermo-geometric parameters of the fin and the internal heat generation within the fin. The obtained results can provide a platform for improvements in the design of the fin in the heat transfer equipment.

  2. Internal film cooling of permanent magnet external rotor machine using the example of a small wind power generator; Innenkuehlung permanentmagneterregter Aussenlaeufermaschinen am Beispiel eines Kleinwindenergiegenerators

    Energy Technology Data Exchange (ETDEWEB)

    Miersch, Soeren; Eckart, Martin; Michalke, Norbert [HTW Dresden (Germany)

    2011-07-01

    This article discusses the fluid flow and thermal cooling system design of a permanent magnet small wind power generator in external rotor construction. Analytical calculation attachment pieces and numerical simulations will be served as authoring tool. Calculation and simulation results will be exhibited in comparing with model and prototype measurements. With the help of stationary temperature allocation, the effectiveness of intensive internal film cooling will be shown. (orig.)

  3. Advances in nonlinear polymers and inorganic crystals, liquid crystals, and laser media

    International Nuclear Information System (INIS)

    Musikant, S.

    1987-01-01

    These proceedings collect papers on laser materials. Topics include: solid state lasers, fracture mechanics in laser materials, optical second harmonic generation, nonlinear optics, molecular crystals, crystal-phase transformation, and materials for laser fusion reactors

  4. Radioactive Waste Management and Constructing Memory for Future Generations. Proceedings of the International Conference and Debate, 15-17 September 2014, Verdun, France

    International Nuclear Information System (INIS)

    Schroeder, Jantine; Botez, Radu; Formentini, Marine

    2015-01-01

    The Preservation of Records, Knowledge and Memory (RK and M) across Generations initiative was launched by the Nuclear Energy Agency in 2011 to foster international reflection and progress towards this goal and to meet increasing demands by waste management specialists and other interested parties for viable and shared strategies. The RK and M initiative is now in its second phase, which is to last until 2017. Phase I culminated on 15-17 September 2014 with the organisation of an international conference and debate on 'Constructing Memory' held in Verdun, France. The conference was attended by approximately 200 participants from 17 countries and 3 international organisations. Participants included specialists from the radioactive waste management area and beyond, academics in the fields of archaeology, communications, cultural heritage, geography and history, as well as artists, archivists and representatives from local heritage societies and from communities that could host a radioactive waste repository. (authors)

  5. Repetitively pulsed TEA CO{sub 2} laser and its application for second harmonic generation in ZnGeP{sub 2} crystal

    Energy Technology Data Exchange (ETDEWEB)

    Koval' chuk, L V; Grezev, A N; Niz' ev, V G; Yakunin, V P [Institute on Laser and Information Technologies, Russian Academy of Sciences, Shatura, Moscow Region (Russian Federation); Mezhevov, V S [Kaluga Laser Innovation and Technology Centre, Obninsk, Kaluga region (Russian Federation); Goryachkin, D A [Russian State Scientific Center for Robotics and Technical Cybernetics, St. Petersburg (Russian Federation); Sergeev, V V; Kalintsev, A G [Open Joint Stock Company S.I.Vavilov State Optical Institute, St. Petersburg (Russian Federation)

    2015-10-31

    Experimental results are presented on the development of a radiation source emitting at a wavelength of 4.775 μm with a pulse energy up to 50 mJ and an average power up to several watts in short pulse trains. A TEA CO{sub 2} laser and a nonlinear converter based on a ZnGeP{sub 2} crystal, which are specially designed for these experiments, are described. The main limitations of nonlinear conversion and possible ways to overcome these limitations are considered. (lasers)

  6. FY 1979 Annual report on Sunshine Project results. Research and development of photovoltaic power generation systems (Research and development of vertically drawn ribbon crystals of silicon); 1979 nendo taiyoko hatsuden system no kenkyu kaihatsu seika hokokusho. Silicon tatehiki ribon kessho no kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1980-03-01

    The efforts in this fiscal year for development of methods for vertically drawing ribbon crystals of silicon are directed to the following items, in order to further improve the techniques for vertically drawing two or more ribbon crystals on a continuous basis, developed in the previous fiscal year: (1) tests of the drawing apparatus, developed in the previous fiscal year, to deepen the techniques for drawing the ribbon crystals, (2) modification of the above apparatus to further develop the apparatus for vertically drawing two or more ribbon crystals on a continuous basis, (3) comparison of drawing a single ribbon crystal, conducted separately, with drawing two or more ribbon crystals, to clarify the problems involved in the latter, and (4) basic investigations on the materials for the furnace internals exposed to high temperature, other than the carbon material used at present. The vertically drawn ribbon crystals of silicon is investigated, based on the results obtained in the previous fiscal year that ribbon crystal quality depends on impurities present therein, mainly for (1) quantitative analysis of the impurity elements present in the ribbon crystal, (2) relationship between impurity elements and characteristics of the solar cells made on a trial basis, and (3) investigations on local concentration of the impurity elements. (NEDO)

  7. Development of internal CRD for next generation BWR-endurance and robustness tests of ball-bearing materials in high-pressure and high-temperature water

    International Nuclear Information System (INIS)

    Shoji Goto; Shuichi Ohmori; Michitsugu Mori; Shohei Kawano; Tadashi Narabayashi; Shinichi Ishizato

    2005-01-01

    An internal CRD using a heatproof ceramics insulated coil is under development to be a competitive and higher performance as Next- Generation BWR. In the case of the 1700MWe next generation BWR, adapting the internal CRDs, the reactor pressure vessel is almost equivalent to that of 1356 MWe ABWR. The endurance and robustness tests were examined in order to confirm the durability of the bearing for the internal CRD. The durability of the ball bearing for the internal CRD was performed in the high-pressure and high-temperature reactor water of current BWR conditions. The experimental results confirmed the durability of rotational numbers for the operation length of 60 years. We added the cruds into water to confirm the robustness of the ball bearing. The test results also showed good robustness even in high-density crud conditions, compared with the current BWR. This program is conducted as one of the selected offers for the advertised technical developments of the Institute of Applied Energy founded by METI (Ministry of Economy, Trade and Industry) of Japan. (authors)

  8. A thermodynamic framework for the study of crystallization in polymers

    Science.gov (United States)

    Rao, I. J.; Rajagopal, K. R.

    In this paper, we present a new thermodynamic framework within the context of continuum mechanics, to predict the behavior of crystallizing polymers. The constitutive models that are developed within this thermodynamic setting are able to describe the main features of the crystallization process. The model is capable of capturing the transition from a fluid like behavior to a solid like behavior in a rational manner without appealing to any adhoc transition criterion. The anisotropy of the crystalline phase is built into the model and the specific anisotropy of the crystalline phase depends on the deformation in the melt. These features are incorporated into a recent framework that associates different natural configurations and material symmetries with distinct microstructural features within the body that arise during the process under consideration. Specific models are generated by choosing particular forms for the internal energy, entropy and the rate of dissipation. Equations governing the evolution of the natural configurations and the rate of crystallization are obtained by maximizing the rate of dissipation, subject to appropriate constraints. The initiation criterion, marking the onset of crystallization, arises naturally in this setting in terms of the thermodynamic functions. The model generated within such a framework is used to simulate bi-axial extension of a polymer film that is undergoing crystallization. The predictions of the theory that has been proposed are consistent with the experimental results (see [28] and [7]).

  9. Heat transfer in a two-pass internally ribbed turbine blade coolant channel with cylindrical vortex generators

    Energy Technology Data Exchange (ETDEWEB)

    Hibbs, R.; Chen, Y.; Nikitopoulos, D. [Louisiana State Univ., Baton Rouge, LA (United States)] [and others

    1995-10-01

    The effect of vortex generators on the mass (heat) transfer from the ribbed passage of a two pass turbine blade coolant channel is investigated with the intent of optimizing the vortex generator geometry so that significant enhancements in mass/heat transfer can be achieved. In the experimental configuration considered, ribs are mounted on two opposite walls; all four walls along each pass are active and have mass transfer from their surfaces but the ribs are non-participating. Mass transfer measurements, in the form of Sherwood number ratios, are made along the centerline and in selected inter-rib modules. Results are presented for Reynolds number in the range of 5,000 to 40,000, pitch to rib height ratios of 10.5 and 21, and vortex generator-rib spacing to rib height ratios of 0.55, and 1.5. Centerline and spanwise averaged Sherwood number ratios are presented along with contours of the Sherwood number ratios. Results indicate that the vortex generators induce substantial increases in the local mass transfer rates, particularly along the side walls, and modest increases in the average mass transfer rates. The vortex generators have the effect of making the inter-rib profiles along the ribbed walls more uniform. Along the side walls, horse-shoe vortices that characterize the vortex generator wake are associated with significant mass transfer enhancements. The wake effects and the levels of enhancement decrease somewhat with increasing Reynolds number and decreasing pitch.

  10. Magnetic small-angle scattering of subthermal neutrons by internal stress fields in work-hardened nickel single crystals oriented for multiple glide

    International Nuclear Information System (INIS)

    Vorbrugg, W.; Schaerpf, O.

    1975-01-01

    The small-angle scattering of Ni single crystals with (111) and (100) axis orientation is measured by a photographic method in the work-hardened state after tensile deformation. Parameters are the external magnetic field H parallel to the axis (600 2 ]<=8,8), and the elastic stress tausub(el)(0<=tausub(el)<=tausub(pl)) applied to the deformed crystals during the experiments. The scattering is found to be anisotropic and characteristic for the chosen orientation. The quantitative photometric analysis shows that the parameters mentioned above only influence the intensity but not the distribution of the scattered neutrons. The scattering increases with the elastic stress and decreases with the magnetic field. In particular, in the unloaded state there is a linear relation between the scattered intensity and the plastic shear stress. (author)

  11. Fiscal 1976 Sunshine Project result report. R and D on photovoltaic power generation system (R and D on Si ribbon crystal vertical pulling method); 1976 nendo taiyoko hatsuden system no kenkyu kaihatsu seika hokokusho. Silicon tatehiki ribbon kessho no kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1977-03-31

    This report describes the fiscal 1976 research result on Si ribbon crystal vertical pulling method for photovoltaic power generation systems. The equipment for simultaneous growth of 3 ribbon crystals was designed and prepared in consideration of capillary die arrangement, vertical pulling method and control method of temperature profiles on the die surface. The temperature profiles on the die surface were controlled by subheaters for 3 parts of each capillary die which were divided longitudinally. Ribbon crystals grew up to 5mm simultaneously through both end dies. By cooling a part of crystal, fast pulling is probably possible. Study was made on the correlation between various crystal defects of Si ribbon crystals and cell characteristics, and in particular, basic characteristics of SiC deposited particles by SEM observation to reduce their impacts. Possibility of simultaneous vertical pulling of crystals was verified by using a capillary carbon die for multi-pulling. Although crystals grew by eutectic reaction under saturated dissolution of carbon, crystals with no transition were obtained. An SiC-coated die was excellent rather than carbon one. (NEDO)

  12. The Observation of SAR, Optical and Altimeter Data to Study the Generation of Internal Wave in Tsushima Strait

    Science.gov (United States)

    Arvelyna, Y.; Oshima, M.

    2006-07-01

    This study proposes D iscr eet Mey er wavelet tr ansform and spectr al reflectan ce analysis for internal w ave detection in ERS1/2 and ASTER imag es data over the Tsushima Strait, Jap an, during 1993-2004 period. The wavelet tr ansform of imag e w as successfully der ived the intern al wav e f eature with h igher w avelet coeff icien t than sea surf ace, i.e. between 2-4.59 times, on horizon tal and vertical d etail coefficient at level 2-5, incr eased the detection probability over 80%. The intern al w ave is modeled using Co mbined Korteweg the Vries (combKdV) model. Non linier speed of in ternal wave is calculated about 85 cm-1. Th e altimetry data products from Topex/Poseidon and Jason-1 data are used to predict th e internal wav e gener ation. Th e observation results show th e propagation of in ternal w aves wer e varied between N W-SW at eastern channel and N-SW at western channel of Tsush ima Strait, p arallel to the direction of the geostrophic curren t. A t NE coast off Tsushima Island, the direction is on S/SE dir ection. I t is suggested th at th e internal wav es w ere sourced from south co ast off Tsush ima Island and south coast off the Japan Sea. They w ere possib ly tid ally gen erated and formed due to bathymetr ic change.

  13. Third-harmonic generation in silicon and photonic crystals of macroporous silicon in the spectral intermediate-IR range; Erzeugung der Dritten Harmonischen in Silizium und Photonischen Kristallen aus makroporoesem Silizium im spektralen mittleren IR-Bereich

    Energy Technology Data Exchange (ETDEWEB)

    Mitzschke, Kerstin

    2007-11-01

    Nonlinear optical spectroscopy is a powerful method to study surface or bulk properties of condensed matter. In centrosymmetric materials like silicon even order nonlinear optical processes are forbidden. Besides self-focussing or self phase modulation third-harmonic-generation (THG) is the simplest process that can be studied. This work demonstrates that THG is a adapted non-contact and non-invasive optical method to get information about bulk structures of silicon and Photonic crystals (PC), consisting of silicon. Until now most studies are done in the visible spectral range being limited by the linear absorption losses. So the extension of THG to the IR spectral range is extremely useful. This will allow the investigation of Photonic Crystals, where frequencies near a photonic bandgap are of special interest. 2D- photonic structures under investigation were fabricated via photoelectrochemical etching of the Si (100) wafer (thickness 500 {mu}m) receiving square and hexagonal arranged pores. The typical periodicity of the structures used is 2 {mu}m and the length of the pores reached to 400 {mu}m. Because of stability the photonic structures were superimposed on silicon substrate. The experimental set-up used for the THG experiments generates tuneable picosecond IR pulses (tuning range 1500-4000 cm{sup -1}). The IR-pulse hit the sample either perpendicular to the sample surface or under an angle {theta}. The sample can be rotated (f) around the surface normal. The generated third harmonic is analysed by a polarizer, spectrally filtered by a polychromator and registered by a CCD camera. The setup can be used either in transmission or in reflection mode. Optical transmission and reflection spectra of the Si bulk correspond well with the theoretical description, a 4-fold and a 8-fold dependencies of the azimuth angle resulting in the structure of the x{sup (3)}-tensor of (100)-Si. The situation changes dramatically if the PC with hexagonal structure is investigated

  14. The Effect of CO2 on Partial Reactive Crystallization of MORB-Eclogite-derived Basaltic Andesite in Peridotite and Generation of Silica-Undersaturated Basalts

    Science.gov (United States)

    Mallik, A.; Dasgupta, R.

    2012-12-01

    Recycled oceanic crust (MORB-eclogite) is considered to be the dominant heterogeneity in Earth's mantle. Because MORB-eclogite is more fusible than peridotite, siliceous partial melt derived from it must react with peridotite while the latter is still in the subsolidus state. Thus, studying such reactive process is important in understanding melting dynamics of the Earth's mantle. Reaction of MORB-eclogite-derived andesitic partial melt with peridotite can produce alkalic melts by partial reactive crystallization but these melts are not as silica-undersaturated as many natural basanites, nephelinites or melititites [1]. In this study, we constrain how dissolved CO2 in a siliceous MORB-eclogite-derived partial melt affects the reaction phase equilibria involving peridotite and can produce nephelinitic melts. Here we compare experiments on CO2-free [1] and 2.6 wt.% CO2 bearing andesitic melt+lherzolite mixtures conducted at 1375 °C and 3 GPa with added melt fraction of 8-50 wt.%. In both CO2-free and CO2-bearing experiments, melt and olivine are consumed and opx and garnet are produced, with the extent of modal change for a given melt-rock ratio being greater for the CO2-bearing experiments. While the residue evolves to a garnet websterite by adding 40% of CO2-bearing melt, the residue becomes olivine-free by adding 50% of the CO2-free melt. Opx mode increases from 12 to ~55 wt.% for 0 to 40% melt addition in CO2-bearing system and 12 to ~43 wt.% for 0 to 50% melt addition in CO2-free system. Garnet mode, for a similar range of melt-rock ratio, increases from ~10 to ~15 wt.% for CO2 bearing system and to ~11 wt.% for CO2-free system. Reacted melts from 25-33% of CO2-bearing melt-added runs contain ~39 wt.% SiO2 , ~11-13 wt.% TiO2, ~9 wt.% Al2O3, ~11 wt.% FeO*, 16 wt.% MgO, 10-11 wt.% CaO, and 3 wt.% Na2O whereas experiments with a similar melt-rock ratio in a CO2-free system yield melts with 44-45 wt.% SiO2, 6-7 wt.% TiO2, 13-14 wt.% Al2O3, 10-11 wt.% FeO*, 12-13 wt

  15. Non-critically phase-matched second harmonic generation and third order nonlinearity in organic crystal glucuronic acid γ-lactone

    Science.gov (United States)

    Saripalli, Ravi Kiran; Katturi, Naga Krishnakanth; Soma, Venugopal Rao; Bhat, H. L.; Elizabeth, Suja

    2017-12-01

    The linear, second order, and third order nonlinear optical properties of glucuronic acid γ-lactone single crystals were investigated. The optic axes and principal dielectric axes were identified through optical conoscopy and the principal refractive indices were obtained using the Brewster's angle method. Conic sections were observed which is perceived to be due to spontaneous non-collinear phase matching. The direction of collinear phase matching was determined and the deff evaluated in this direction was 0.71 pm/V. Open and closed aperture Z-scan measurements with femtosecond pulses revealed high third order nonlinearity in the form of self-defocusing, two-photon absorption, as well as saturable absorption.

  16. Experimental study on single-phase convection heat transfer characteristics of pebble bed channels with internal heat generation

    International Nuclear Information System (INIS)

    Meng Xianke; Sun Zhongning; Zhou Ping; Xu Guangzhan

    2012-01-01

    The water-cooled pebble bed reactor core is the porous channels stacked with spherical fuel elements, having evident effect on enhancing heat transfer. Owing to the variability and randomness characteristics of it's interstice, pebble bed channels have a very complex heat transfer situation and have little correlative research. In order to research the heat transfer characters of pebble bed channels with internal heat source, electromagnetic induction heating method was adopted for overall heating the pebble bed which was composed of 8 mm diameter steel balls, and the internal heat transfer characteristics were researched. By comparing and analyzing the experimental data, the rule of power distribution and heat transfer coefficient with heat flux density, inlet temperature and working fluid's Re were got. According to the experimental data fitting, the dimensionless average heat transfer coefficient correlation criteria was got. The fitting results are good agreement with the experimental results within 12% difference. (authors)

  17. The challenges of commercializing second-generation transgenic crop traits necessitate the development of international public sector research infrastructure.

    Science.gov (United States)

    Rothstein, Steven J; Bi, Yong-Mei; Coneva, Viktoriya; Han, Mei; Good, Allen

    2014-10-01

    It has been 30 years since the first transformation of a gene into a plant species, and since that time a number of biotechnology products have been developed, with the most important being insect- and herbicide-resistant crops. The development of second-generation products, including nutrient use efficiency and tolerance to important environmental stressors such as drought, has, up to this time, been less successful. This is in part due to the inherent complexities of these traits and in part due to limitations in research infrastructure necessary for public sector researchers to test their best ideas. Here we discuss lessons from previous work in the generation of the first-generation traits, as well as work from our labs and others on identifying genes for nitrogen use efficiency. We then describe some of the issues that have impeded rapid progress in this area. Finally, we propose the type of public sector organization that we feel is necessary to make advances in important second-generation traits such as nitrogen use efficiency. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  18. Safety approach and research and development presentation for the selected systems of the International forum Generation IV

    International Nuclear Information System (INIS)

    Fiorini, G.L.

    2003-01-01

    This paper deals with the six projects of the Generation IV forum: Sodium Fast reactor, lead fast reactor, gas fast reactor, very high temperature reactor, supercritical water reactor, molten salt reactor. The technical objectives of the reactor safety and the design/evaluation approach are discussed. (A.L.B.)

  19. Student Recruitment for the Mobile Generation : An Exploratory Study of Mobile Marketing Practices in the International Higher Education Industry

    OpenAIRE

    Zinn, Marian; Johansson, Helen

    2015-01-01

    Background: In an increasingly market-driven and global higher education industry, characterized by growing international competition and the emergence of disruptive mobile technologies, higher education institutions (HEIs) are challenged to adopt innovative ways of marketing for student recruitment to sustain student enrollment numbers. Within this new landscape the concept of mobile marketing for student recruitment has become an important issue for HEIs. Mobile devices are playing an incre...

  20. Marginal and Internal Fit of Cobalt-Chromium Fixed Dental Prostheses Generated from Digital and Conventional Impressions

    OpenAIRE

    Svanborg, Per; Skjerven, Henrik; Carlsson, Pablo; Eliasson, Alf; Karlsson, Stig; Örtorp, Anders

    2014-01-01

    Objectives. Digital impressions are increasingly used and have the potential to avoid the problem of inaccurate impressions. Only a few studies to verify the accuracy of digital impressions have been performed. The purpose of this study was to compare the marginal and internal fit of 3-unit tooth supported fixed dental prostheses (FDPs) fabricated from digital and conventional impressions. Methods. Ten FDPs were produced from digital impressions using the iTero system and 10 FDPs were produce...

  1. Comparative analysis between a PEM fuel cell and an internal combustion engine driving an electricity generator: Technical, economical and ecological aspects

    International Nuclear Information System (INIS)

    Braga, Lúcia Bollini; Silveira, Jose Luz; Evaristo da Silva, Marcio; Machin, Einara Blanco; Pedroso, Daniel Travieso; Tuna, Celso Eduardo

    2014-01-01

    In the recent years the fuel cells have received much attention. Among various technologies, the Proton Exchange Membrane Fuel Cell (PEMFC) is currently the most appropriate and is used in several vehicles prototype. A comparative technical, economical and ecological analysis between an Internal Combustion Engine fueled with Diesel driving an electricity Generator (ICE-G) and a PEMFC fed by hydrogen produced by ethanol steam reforming was performed. The technical analysis showed the advantages of the PEMFC in comparison to the ICE-G based in energetic and exergetic aspects. The economic analysis shows that fuel cells are not economic competitive when compared to internal combustion engine driving an electricity generator with the same generation capacity; it will only be economically feasible in a long term; due to the large investments required. The environmental analysis was based on concepts of CO 2 equivalent, pollution indicator and ecological efficiency. Different to the ICE-G system, the Fuel Cell does not emit pollutants directly and the emission related to this technology is linked mainly with hydrogen production. The ecological efficiency of PEMFC was 96% considering the carbon dioxide cycle, for ICE-G system this parameter reach 51%. -- Highlights: • The exergetic efficiency of ICE-G was 22% and for the fuel cell was 40%. • The PEM fuel cell at long-term become economically competitive compared to ICE-G. • The ecological efficiency of PEM fuel cell was 96% and Diesel ICE-G was 51%

  2. Crystallization kinetics of magnetic glass-ceramics prepared by the processing of waste materials

    International Nuclear Information System (INIS)

    Francis, A.A.

    2006-01-01

    The objective of the present investigation was to study the feasibility of conversion of an intimate mixture of blast furnace slag and blast furnace flue dust generated by a single industrial company into magnetic glass-ceramic product. Blast furnace slag (BFS) and blast furnace flue dust (BFD) are generated at a rate of 300,000 and 30,000 tons/year, respectively, from iron and steel factory. The crystallization mechanisms of a composition containing BFS and BFD in a 50/50 proportion were investigated by differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The crystallization temperature was found to vary from 900 to 1100 deg. C and two phases appeared in the crystallized samples: pyroxene Ca(Mg, Fe, Al)(Si, Al) 2 O 6 and magnetite/maghemite. Heating rate and particle sizes effects on crystal growth of powdered samples were studied by DTA. The apparent activation energy of crystal growth using the particle size 180-315 μm was determined to be 355 and 329 kJ/mol for the first and second peak, respectively. The presence of sharp and broad crystallization peaks indicate simultaneous surface and internal crystallization mechanism. Good wear resistance and chemical durability particularly in alkaline environment, combine with good hardness and magnetic properties make this glass-ceramic material potentially useful for various industrial applications

  3. Debye series analysis of internal and near-surface fields for a homogeneous sphere illuminated by an axicon-generated vector Bessel beam

    International Nuclear Information System (INIS)

    Qin, Shitong; Li, Renxian; Yang, Ruiping; Ding, Chunying

    2017-01-01

    The interaction of an axicon-generated vector Bessel beam (AGVBB) with a homogeneous sphere is investigated in the framework of generalized Lorenz-Mie theory (GLMT). An analytical expression of beam shape coefficients (BSCs) is derived using angular spectrum decomposition method (ASDM), and the scattering coefficients are expanded using Debye series (DSE) in order to isolate the contribution of single scattering process. The internal and near-surface electric fields are numerically analyzed, and the effect of beam location, polarization, order of beam, half-cone angle, and scattering process (namely Debye mode p) are mainly discussed. Numerical results show that a curve formed by extreme peaks can be observed, and the electric fields can be locally enhanced after the interaction of AGVBBs with the particle. Internal and near-surface fields, especially its local enhancement, are very sensitive to the beam parameters, including polarization, order, half-cone angle, etc. The internal fields can also be enhanced by various scattering process (or Debye mode p). Such results have important applications in various fields, including particle sizing, optical tweezers, etc. - Highlights: • Debye series is employed to the analysis of internal and near-surface fields for a sphere illuminated by a vector Bessel beam. • Analytical expressions of BSCs for vector Bessel beams with selected polarizations are derived using ASDM. • The local enhancement of internal and near-surface fields is investigated. • The polarization, order, half-cone angle of the beam affect the local enhancement. • The local enhancement of internal fields is sensitive to the scattering process.

  4. Shape Evolution of Detached Bridgman Crystals Grown in Microgravity

    Science.gov (United States)

    Volz, M. P.; Mazuruk, K.

    2015-01-01

    A theory describing the shape evolution of detached Bridgman crystals in microgravity has been developed. A starting crystal of initial radius r0 will evolve to one of the following states: Stable detached gap; Attachment to the crucible wall; Meniscus collapse. Only crystals where alpha plus omega is great than 180 degrees will achieve stable detached growth in microgravity. Results of the crystal shape evolution theory are consistent with predictions of the dynamic stability of crystallization (Tatarchenko, Shaped Crystal Growth, Kluwer, 1993). Tests of transient crystal evolution are planned for ICESAGE, a series of Ge and GeSi crystal growth experiments planned to be conducted on the International Space Station (ISS).

  5. ISO 14000 - the International Environmental Management Standard: Potential impacts on environmental management and auditing in the electric power generation industry

    International Nuclear Information System (INIS)

    Gauntlett, S.B.; Pierce, J.L.; Pierce, J.L.

    1995-01-01

    In the framework of environmental management, the concept of voluntary environmental compliance auditing is not in itself a new development. Environmentally conscious firms have for more than a decade, undertaken voluntary audits to help achieve and maintain compliance with environmental regulations and to help identify and correct unregulated or poorly regulated environmental hazard. The firms undertaking the audits were motivated by a desire to mitigate legal and financial risks and/or the desire to be a highly responsible member of the corporate community. Much of the early attention to environmental auditing was in the chemical process industries. Today, there are four current trends affecting environmental auditing: (1) the practice is becoming widespread in all industry groups in both large and small firms; (2) environmental management and audit methodolgies and approaches are being codified in the form of written national and International standards; (3) environmental management programs and in-house audits are increasingly being certified by independent auditors (who are not associated with regulatory agencies); and (4) the certifications are being viewed as marketing and public relations tools. The adoption of ISO 14000 is destined to become the most significant development in international environmental management and auditing. International standards for the development of Environmental Management Systems and the execution of environmental audits do not currently exist. Individual countries, such as England and France, have national standards. One multi-national standard currently exists--the European Economic Community's Eco-Management and Audit Scheme (EMAS). The United States does not have a national environmental management and auditing standard

  6. Generation of covariance files for iron-56 and natural iron - International Evaluation Co-operation Volume 2

    International Nuclear Information System (INIS)

    Vonach, Herbert; Gruppelaar, Harm; Santamarina, Alain; Froehner, Fritz; Hasegawa, Akira; Kanda, Yukinori; Sugimoto, Masayoshi; Kopecky, J.; Fu, C.Y.; Hetrick, David M.; Larson, Duane C.; Peelle, R.W.

    1994-01-01

    A Working Party on International Evaluation Co-operation was established under the sponsorship of the OECD/NEA Nuclear Science Committee (NSC) to promote the exchange of information on nuclear data evaluations, validation, and related topics. Its aim is also to provide a framework for co-operative activities between members of the major nuclear data evaluation projects. This includes the possible exchange of scientists in order to encourage co-operation. Requirements for experimental data resulting from this activity are compiled. The Working Party determines common criteria for evaluated nuclear data files with a view to assessing and improving the quality and completeness of evaluated data. The Parties to the project are: ENDF (United States), JEFF/EFF (NEA Data Bank Member countries), and JENDL (Japan). Co-operation with evaluation projects of non-OECD countries are organised through the Nuclear Data Section of the International Atomic Energy Agency (IAEA). The following report was issued by a Subgroup investigating different methodologies to produce covariance data. These data are required to assess uncertainties in design parameters and to refine the use of nuclear data both in fission and fusion reactor applications. It was agreed to limit the scope to covariance data for Iron-56 and natural iron in view of their importance as structural materials in reactors and particularly for fusion reactor shielding applications

  7. FY 1977 Annual report on Sunshine Project results. Research and development of photovoltaic power generation systems (Research and development of particle nonacceleration growth type silicon thin-film crystals); 1977 nendo taiyoko hatsuden system no kenkyu kaihatsu seika hokokusho. Ryushi hikasoku seichogata silicon usumaku kessho no kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1978-03-01

    As part of the research and development project for producing photovoltaic power generation systems at reduced cost, the R and D efforts are made for producing particle nonacceleration growth type silicon thin-film crystals. The research items are (1) research on thin-film crystals, and (2) research on cell-structuring method. The item (1) studies quantities, types and electrical properties of impurities and crystal defects in the polycrystalline ingots, produced by the Czochralski method from metal grade silicon and purified metal grade silicon stocks. Next, the substrate prepared above is coated with a thin film of silicon by the vapor-phase growth method with dichlorosilane as the source, to evaluate the thin-film crystals by measuring the crystal defects and lifetime of small numbers of carriers. The item (2) studies the effects of the solder dipping method. In addition, unevenness of photoelectric current is analyzed by a laser scanning microscope, to investigate the effects of the secondary impurities and crystal defects in the substrate crystals on photoelectric current. As a result, it is found that conversion efficiency is improved by grading the hole concentration in the p-type activated layer. The targets of 10 to 20 m{sup 2} as the area and 7 to 8% as the conversion efficiency are attained by preparing the crystals again. (NEDO)

  8. Generation of laser-induced periodic surface structures in indium-tin-oxide thin films and two-photon lithography of ma-N photoresist by sub-15 femtosecond laser microscopy for liquid crystal cell application

    Science.gov (United States)

    Klötzer, Madlen; Afshar, Maziar; Feili, Dara; Seidel, Helmut; König, Karsten; Straub, Martin

    2015-03-01

    Indium-tin-oxide (ITO) is a widely used electrode material for liquid crystal cell applications because of its transparency in the visible spectral range and its high electrical conductivity. Important examples of applications are displays and optical phase modulators. We report on subwavelength periodic structuring and precise laser cutting of 150 nm thick indium-tin-oxide films on glass substrates, which were deposited by magnetron reactive DC-sputtering from an indiumtin target in a low-pressure oxygen atmosphere. In order to obtain nanostructured electrodes laser-induced periodic surface structures with a period of approximately 100 nm were generated using tightly focused high-repetition rate sub-15 femtosecond pulsed Ti:sapphire laser light, which was scanned across the sample by galvanometric mirrors. Three-dimensional spacers were produced by multiphoton photopolymerization in ma-N 2410 negative-tone photoresist spin-coated on top of the ITO layers. The nanostructured electrodes were aligned in parallel to set up an electrically switchable nematic liquid crystal cell.

  9. Socioeconomic impacts of nuclear generating stations: Crystal River Unit 3 case study. Technical report 1 Oct 78-4 Jan 82

    International Nuclear Information System (INIS)

    Bergmann, P.A.

    1982-07-01

    The report documents a case study of the socioeconomic impacts of the construction and operation of the Crystal River Unit 3 nuclear power station. It is part of a major post-licensing study of the socioeconomic impacts at twelve nuclear power stations. The case study covers the period beginning with the announcement of plans to construct the reactor and ending in the period, 1980-81. The case study deals with changes in the economy, population, settlement patterns and housing, local government and public services, social structure, and public response in the study area during the construction/operation of the reactor. A regional modeling approach is used to trace the impact of construction/operation on the local economy, labor market, and housing market. Emphasis in the study is on the attribution of socioeconomic impacts to the reactor or other causal factors. As part of the study of local public response to the construction/operation of the reactor, the effects of the Three Mile Island accident are examined

  10. Reduction of residual stresses in internal skin of transient zones of PWR steam generator expanded tubes: tests with a ''rotating brush''

    International Nuclear Information System (INIS)

    Vidal, P.

    1984-04-01

    A process aiming at preventing or suppressing cracks under stress corrosion on the primary side in the expanded zones of PWR steam generator tubes has been studied; it consists in hammering the internal skin of tubes in these zones what reduces the level of residual expanding stresses to lower values around 100-150 MPa without modifying the stress level in external skin. Tests in magnesium chloride to estimate the residual stresses of tubes in low carbon stainless austenitic steel 18% Cr-12% Ni with molybdene [fr

  11. Efficient turbine control. Advantages through controlling internal turbine power in place of turbo generator output; Effektive Turbinenregelung. Vorteile durch die Regelung der inneren Turbinenleistung anstelle der Turbogeneratorleistung

    Energy Technology Data Exchange (ETDEWEB)

    Sindelar, R.

    1999-07-01

    Hitherto, the electrical output of turbo generators has generally been controlled by means of power output controllers. Load changes caused, for example, by changeovers to isolated unit operation where the load requirements are unknown at first, often resulted in `wrong way control` effects that sometimes even caused entire turbine generator sets to fail. Controlling the internal turbine power makes it possible to avoid such consequences. (orig.) [Deutsch] Die elektrische Leistung eines Turbogenerators wurde bislang durch Leistungsregler geregelt. Im Falle einer Lastaenderung, wie sie beispielsweise beim Uebergang in den Betrieb auf ein Teilnetz (Insel-) mit vorher unbekannter Last vorkommt, trat ein Falschregeleffekt auf. Auf diesen wurden bereits Turbosatzausfaelle zurueckgefuehrt. Wird anstelle der elektrischen Leistung allerdings die innere Turbinenleistung geregelt, so tritt der Falschregeleffekt nicht ein. (orig.)

  12. Book of abstracts: 3rd International Conference on Smart Energy Systems and 4th Generation District Heating

    DEFF Research Database (Denmark)

    This year the conference is organised by two research centres/projects in collaboration with Aalborg University. The first is the 4DH Strategic Research Centre and the other is the project RE-INVEST, both supported financial by the Danish Innovation Fund. After the previous two year´s success...... everyone for your valuable contributions. The aim is to present and discuss scientific findings and industrial experiences related to the development of Smart Energy Systems and future 4th Generation District Heating Technologies and Systems (4GDH). This development is fundamental to the implementation...

  13. Generating a 2.4-W cw Green Laser by Intra-Cavity Frequency Doubling of a Diode-Pumped Nd:GdVO4 Laser with a MgO:PPLN Crystal

    International Nuclear Information System (INIS)

    Lu Jun; Liu Yan-Hua; Zhao Gang; Hu Xiao-Peng; Zhu Shi-Ning

    2012-01-01

    High-power cw green laser radiation is generated by intra-cavity frequency doubling of a diode-pumped Nd:GdVO 4 laser with a MgO-doped periodically-poled LiNbO 3 (MgO:PPLN) crystal at room temperature. An average power of 2.4 W at 0.53 μm is obtained under the pump 15 W at 808 nm, corresponding to an overall optical-to-optical conversion efficiency of 16%. The M 2 factor of the green beam is 3.90 and 1.34 for the horizontal and vertical direction, respectively. In addition, the power fluctuation is measured to be about ±5%

  14. Mean flow generated by an internal wave packet impinging on the interface between two layers of fluid with continuous density

    Energy Technology Data Exchange (ETDEWEB)

    McHugh, John P. [The University of New Hampshire, Department of Mechanical Engineering, Kingsbury Hall, Durham, NH (United States)

    2008-04-15

    Internal waves propagating in an idealized two-layer atmosphere are studied numerically. The governing equations are the inviscid anelastic equations for a perfect gas atmosphere. The numerical formulation eliminates all variables in the linear terms except vertical velocity, which are then treated implicitly. Nonlinear terms are treated explicitly. The basic state is a two-layer flow with continuous density at the interface. Each layer has a unique constant for the Brunt-Vaeisaelae frequency. Waves are forced at the bottom of the domain, are periodic in the horizontal direction, and form a finite wave packet in the vertical. The results show that the wave packet forms a mean flow that is confined to the interface region that persists long after the wave packet has moved away. Large-amplitude waves are forced to break beneath the interface. (orig.)

  15. Metallic materials for heat exchanger components and highly stressed internal of HTR reactors for nuclear process heat generation

    International Nuclear Information System (INIS)

    1982-01-01

    The programme was aimed at the development and improvement of materials for the high-temperature heat exchanger components of a process steam HTR. The materials must have high resistance to corrosion, i.e. carburisation and internal oxidation, and high long-term toughness over a wide range of temperatures. They must also meet the requirements set in the nuclear licensing procedure, i.e. resistance to cyclic stress and irradiation, non-destructive testing, etc. Initially, it was only intended to improve and qualify commercial alloys. Later on an alloy development programme was initiated in which new, non-commercial alloys were produced and modified for use in a nuclear process heat facility. Separate abstracts were prepared for 19 pays of this volume. (orig./IHOE) [de

  16. Automatic Generation of Object Models for Process Planning and Control Purposes using an International standard for Information Exchange

    Directory of Open Access Journals (Sweden)

    Petter Falkman

    2003-10-01

    Full Text Available In this paper a formal mapping between static information models and dynamic models is presented. The static information models are given according to an international standard for product, process and resource information exchange, (ISO 10303-214. The dynamic models are described as Discrete Event Systems. The product, process and resource information is automatically converted into product routes and used for simulation, controller synthesis and verification. A high level language, combining Petri nets and process algebra, is presented and used for speci- fication of desired routes. A main implication of the presented method is that it enables the reuse of process information when creating dynamic models for process control. This method also enables simulation and verification to be conducted early in the development chain.

  17. Evaluation of the methodologies used to generate random pavement profiles based on the power spectral density: An approach based on the International Roughness Index

    Directory of Open Access Journals (Sweden)

    Boris Jesús Goenaga

    2017-01-01

    Full Text Available The pavement roughness is the main variable that produces the vertical excitation in vehicles. Pavement profiles are the main determinant of (i discomfort perception on users and (ii dynamic loads generated at the tire-pavement interface, hence its evaluation constitutes an essential step on a Pavement Management System. The present document evaluates two specific techniques used to simulate pavement profiles; these are the shaping filter and the sinusoidal approach, both based on the Power Spectral Density. Pavement roughness was evaluated using the International Roughness Index (IRI, which represents the most used index to characterize longitudinal road profiles. Appropriate parameters were defined in the simulation process to obtain pavement profiles with specific ranges of IRI values using both simulation techniques. The results suggest that using a sinusoidal approach one can generate random profiles with IRI values that are representative of different road types, therefore, one could generate a profile for a paved or an unpaved road, representing all the proposed categories defined by ISO 8608 standard. On the other hand, to obtain similar results using the shaping filter approximation a modification in the simulation parameters is necessary. The new proposed values allow one to generate pavement profiles with high levels of roughness, covering a wider range of surface types. Finally, the results of the current investigation could be used to further improve our understanding on the effect of pavement roughness on tire pavement interaction. The evaluated methodologies could be used to generate random profiles with specific levels of roughness to assess its effect on dynamic loads generated at the tire-pavement interface and user’s perception of road condition.

  18. Properties of the generation of radiation in the near infrared part of the spectrum with a sapphire crystal laser having radiation-induced color centers

    International Nuclear Information System (INIS)

    Voitovich, A.P.; Grinkevich, V.E.; Kononov, V.A.; Kromskii, G.I.

    1986-01-01

    This paper investigates the spectral stability of the color centers in sapphire and the energy of lasers in which the active elements were colored with various techniques. Color centers were produced by neutron irradiation. The absorption spectra of the color centers are shown. The transformation of the spectra shows that the mutual conversions of color centers takes place during the thermal annealing of the sapphire; most of the color centers formed have luminescence. Generation or radiation with a tunable frequency was obtained in the case of transverse or quasi-longitudinal excitation by a ruby laser. The results show that ways for increasing the stability of the energy generated by a sapphire laser with color centers can be found

  19. Springer Handbook of Crystal Growth

    CERN Document Server

    Dhanaraj, Govindhan; Prasad, Vishwanath; Dudley, Michael

    2010-01-01

    Over the years, many successful attempts have been made to describe the art and science of crystal growth. Most modern advances in semiconductor and optical devices would not have been possible without the development of many elemental, binary, ternary, and other compound crystals of varying properties and large sizes. The objective of the Springer Handbook of Crystal Growth is to present state-of-the-art knowledge of both bulk and thin-film crystal growth. The goal is to make readers understand the basics of the commonly employed growth processes, materials produced, and defects generated. Almost 100 leading scientists, researchers, and engineers from 22 different countries from academia and industry have been selected to write chapters on the topics of their expertise. They have written 52 chapters on the fundamentals of bulk crystal growth from the melt, solution, and vapor, epitaxial growth, modeling of growth processes and defects, techniques of defect characterization as well as some contemporary specia...

  20. Purification, crystallization and preliminary X-ray analysis of urease from pigeon pea (Cajanus cajan)

    Energy Technology Data Exchange (ETDEWEB)

    Balasubramanian, Anuradha; Ponnuraj, Karthe, E-mail: pkarthe@hotmail.com [Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025 (India)

    2008-07-01

    Urease from pigeon pea was purified and crystallized and X-ray diffraction data were collected at 2.5 Å resolution. Urease is a seed protein that is common to most Leguminosae. It also occurs in many bacteria, fungi and several species of yeast. Urease catalyzes the hydrolysis of urea to ammonia and carbon dioxide, thus allowing organisms to use exogenous and internally generated urea as a nitrogen source. Urease from pigeon pea seeds has been purified to electrophoretic homogeneity using a series of steps involving ammonium sulfate fractionation, acid precipitation, ion-exchange and size-exclusion chromatography techniques. The pigeon pea urease was crystallized and the resulting crystals diffracted to 2.5 Å resolution. The crystals belong to the rhombohedral space group R32, with unit-cell parameters a = b = 176.29, c = 346.44 Å.