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Sample records for break loca analysis

  1. Analysis of different containment models for IRIS small break LOCA, using GOTHIC and RELAP5 codes

    Energy Technology Data Exchange (ETDEWEB)

    Papini, Davide, E-mail: davide.papini@mail.polimi.i [Department of Energy, CeSNEF - Nuclear Engineering Division, Politecnico di Milano, Via La Masa 34, 20156 Milano (Italy); Grgic, Davor [Department of Power Systems, FER, University of Zagreb, Unska 3, 10000 Zagreb (Croatia); Cammi, Antonio; Ricotti, Marco E. [Department of Energy, CeSNEF - Nuclear Engineering Division, Politecnico di Milano, Via La Masa 34, 20156 Milano (Italy)

    2011-04-15

    Advanced nuclear water reactors rely on containment behaviour in realization of some of their passive safety functions. Steam condensation on containment walls, where non-condensable gas effects are significant, is an important feature of the new passive containment concepts, like the AP600/1000 ones. In this work the international reactor innovative and secure (IRIS) was taken as reference, and the relevant condensation phenomena involved within its containment were investigated with different computational tools. In particular, IRIS containment response to a small break LOCA (SBLOCA) was calculated with GOTHIC and RELAP5 codes. A simplified model of IRIS containment drywell was implemented with RELAP5 according to a sliced approach, based on the two-pipe-with-junction concept, while it was addressed with GOTHIC using several modelling options, regarding both heat transfer correlations and volume and thermal structure nodalization. The influence on containment behaviour prediction was investigated in terms of drywell temperature and pressure response, heat transfer coefficient (HTC) and steam volume fraction distribution, and internal recirculating mass flow rate. The objective of the paper is to preliminarily compare the capability of the two codes in modelling of the same postulated accident, thus to check the results obtained with RELAP5, when applied in a situation not covered by its validation matrix (comprising SBLOCA and to some extent LBLOCA transients, but not explicitly the modelling of large dry containment volumes). The option to include or not droplets in fluid mass flow discharged to the containment was the most influencing parameter for GOTHIC simulations. Despite some drawbacks, due, e.g. to a marked overestimation of internal natural recirculation, RELAP5 confirmed its capability to satisfactorily model the basic processes in IRIS containment following SBLOCA.

  2. Robinson 2 reactor vessel: pressurized thermal shock analysis for a small-break LOCA

    Energy Technology Data Exchange (ETDEWEB)

    Marston, T.; Griesbach, T.; Chao, J.; Chexal, B.; Norris, D.; Nickell, B.; Layman, B.

    1984-08-01

    A best-estimate Pressurized Thermal Shock (PTS) analysis was performed for a three-inch diameter hot-leg small-break loss-of-coolant accident for the Robinson 2 plant. This plant specific analysis was performed using EPRI's linked set of codes for PTS analysis. The analysis shows that with the H.B. Robinson 2 reactor pressure vessel, a hot-leg small-break loss-of-coolant accident does not pose a significant health or safety concern to the public for at least 40 years of operation.

  3. A Demonstration of Advanced Safety Analysis Tools and Methods Applied to Large Break LOCA and Fuel Analysis for PWRs

    Energy Technology Data Exchange (ETDEWEB)

    Szilard, Ronaldo Henriques [Idaho National Laboratory; Smith, Curtis Lee [Idaho National Laboratory; Martineau, Richard Charles [Idaho National Laboratory

    2016-03-01

    The U.S. Nuclear Regulatory Commission (NRC) is currently proposing a rulemaking designated as 10 CFR 50.46c to revise the loss-of-coolant accident (LOCA)/emergency core cooling system acceptance criteria to include the effects of higher burnup on fuel/cladding performance. We propose a demonstration problem of a representative four-loop PWR plant to study the impact of this new rule in the US nuclear fleet. Within the scope of evaluation for the 10 CFR 50.46c rule, aspects of safety, operations, and economics are considered in the industry application demonstration presented in this paper. An advanced safety analysis approach is used, by integrating the probabilistic element with deterministic methods for LOCA analysis, a novel approach to solving these types of multi-physics, multi-scale problems.

  4. Containment Performance Analysis with Large Break LOCA for EU-APR1400

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    Hwang, Do Hyun; Lee, Keun Sung; Kim, Yong Soo [KHNP CRI, Daejeon (Korea, Republic of)

    2013-10-15

    In this paper for containment performance analysis, the containment pressurization analysis is performed and thermo-hydraulic response analysis of containment structure is carried out to provide basic understanding of containment transient states under a severe accident sequence. Especially, in EU-APR1400 design, to reduce containment pressure and temperature, Severe Accident Containment Spray System (SACSS) is designed to be actuated automatically when Core Exit Temperature (CET) reaches 922 K (649 .deg. C). The containment performance analysis was carried on LBLOCA sequence for EU-APR1400 with SACSS through MAAP code. If SACSS is actuated when CET reaches 922 K (649 .deg. C) , the containment pressure and temperature decrease to a sufficient low level. The predicted atmospheric pressure of containment will not exceed the ultimate pressure capacity (UPC) and have a sufficient margin to it even though the UPC of the reference plant (Shin-Kori Units 3 and 4) is used instead because the UPC calculation for EU-APR1400 has not been completed. The largest load on the containment by LBLOCA is estimated at 306.1 kPa. Thus the margin to UPC is estimated to be 330 % in comparison with 1.329 MPa as UPC for the reference plant.

  5. Scaling analysis of the thermal-hydraulic test facility for the large break LOCA of KNGR

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    Yun, Byong Jo; Kwon, Tae Soon; Song, Chul Hwa; Euh, Dong Jin; Chu, In Cheol; Cho, Hyoung Kyu; Park, Jong Kyun

    2001-03-01

    Korea Next Generation Reactor(KNGR) adopts a Direct Vessel Injection (DVI) system instead of conventional Cold Leg Injection (CLI) system. In this report, a scaling analysis for the steam-water test facility of KNGR with DVI under reflood phase of Loss of Coolant Accident(LBLOCA) is carried out. The major objectives of the test facility are to clarify the thermal hydraulics phenomena in the upper downcomer region and to provide experimental data for evaluating or validating relevant thermal hydraulic models and correlations of the best estimate codes. The test facility should be designed based on the appropriate scaling law so that the same thermal hydraulics phenomena is happened as in the case of prototype. For these, the investigations of previous scaling laws are carried out. And, in the present study, a new scaling approach, named the modified linear scaling, is developed for the design of a scaled-down experimental facility. Its velocity is scaled by a Wallis-type parameter and an aspect ratio of experimental facility is preserved with that of a prototype. The test facility is designed primarily by a volume scaling law and the area ratio of test facility is set to be 1/24.3. However, additional DVI nozzles are also installed at the elevation which is determined by the modified linear scaling law. It is for the scaling analysis of ECC bypass fraction. The cold leg, hot leg and DVI nozzles are additionally attached in the upper annulus downcomer region so that the UPTF counterpart test is possible.

  6. Cold-Leg Small Break LOCA Analysis of APR1400 Plant Using a SPACE/sEM Code

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Sang Gyu; Lee, Suk Ho; Yu, Keuk Jong; Kim, Han Gon; Lee, Jae Yong [Central Research Institute, KHNP, Ltd., Daejeon (Korea, Republic of)

    2013-10-15

    The Small Break Loss-of-Coolant Accident (SBLOCA) evaluation methodology (EM) for APR1400, called sEM, is now being developed using SPACE code. SPACE/sEM is to set up a conservative evaluation methodology in accordance with appendix K of 10 CFR 50. Major required and acceptable features of the evaluation models are described as below. - Fission product decay : 1.2 times of ANS97 decay curve - Critical flow model : Henry-Fauske Moody two phase critical flow model - Metal-Water reaction model : Baker-Just equation - Critical Heat Flux (CHF) : B and W, Barnett and Modified Barnett correlation - Post-CHF : Groeneveld 5.7 film boiling correlation A series of test matrix is established to validate SPACE/sEM code in terms of major SBLOCA phenomena, e.g. core level swelling and boiling, core heat transfer, critical flow, loop seal clearance and their integrated effects. The separated effect tests (SETs) and integrated effect tests (IETs) are successfully performed and these results shows that SPACE/sEM code has a conservatism comparing with experimental data. Finally, plant calculations of SBLOCA for APR1400 are conducted as described below. - Break location sensitivity : DVI line, hot-leg, cold-leg, pump suction leg. - Break size spectrum : 0.4ft{sup 2}∼0.02ft{sup 2}(DVI) 0.5ft{sup 2}∼0.02ft{sup 2}(hot-leg, cold-leg, pump suction leg) This paper deals with break size spectrum analysis of cold-leg break accidents. Based on the calculation results, emergency core cooling system (ECCS) performances of APR1400 and typical SBLOCA phenomena can be evaluated. Cold-leg SBLOCA analysis for APR1400 is performed using SPACE/sEM code under harsh environment condition. SPACE/sEM code shows the typical SBLOCA behaviors and it is reasonably predicted. Although SPACE/sEM code has conservative models and correlations based on appendix K of 10 CFR 50, PCT does not exceed the requirement (1477 K). It is concluded that ECCS in APR1400 has a sufficient performance in cold-leg SBLOCA.

  7. TASS/SMR code improvement for small break LOCA applicability at an integral type reactor, SMART

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Young-Jong, E-mail: chung@kaeri.re.kr; Kim, Soo-Hyung; Lim, Sung-Won; Bae, Kyoo-Hwan

    2015-12-15

    Highlights: • SMART adopts a passive system to enhance its safety. • TASS/SMR code is developed to analyze thermal hydraulic phenomena of the SMART plant. • Improved TASS/SMR code predicts well the results of the OSU-MASLWR total-loss-of-feedwater test. - Abstract: Small reactors are a suitable option for nuclear system deployment in developing countries or non-electrical applications for various facilities. SMART is one of the small integral type reactors to apply flexibly local power demands or sea water desalination. A thermal hydraulic analysis code, TASS/SMR, having SMART specific models, was developed to simulate thermal hydraulic phenomena of the SMART plant. The improved TASS/SMR code predicts well the system behaviors under two-phase conditions compared with the OSU-MASLWR experimental results. A small break LOCA simulation of the SMART plant is improved a void distribution, a break flow, and a collapsed water level in the core.

  8. Hydrogen and steam distribution following a small-break LOCA in large dry containment

    Institute of Scientific and Technical Information of China (English)

    DENG Jian; CAO Xuewu

    2007-01-01

    The hydrogen deflagration is one of the major risk contributors to threaten the integrity of the containment in a nuclear power plant, and hydrogen control in the case of severe accidents is required by nuclear regulations.Based on the large dry containment model developed with the integral severe-accident analysis tool, a small-break loss-of-coolant-accident (LOCA) without HPI, LPI, AFW and containment sprays, leading to the core degradation and large hydrogen generation, is calculated. Hydrogen and steam distribution in containment compartments is investigated. The analysis results show that significant hydrogen deflagration risk exits in the reactor coolant pump (RCP)compartment and the cavity during the early period, if no actions are taken to mitigate the effects of hydrogen accumulation.

  9. A composite analytical solution for large break LOCA

    Energy Technology Data Exchange (ETDEWEB)

    Purdy, P. [Bruce Power, Tiverton, Ontario (Canada); Girard, R. [Hydro-Quebec, Quebec (Canada); Marczak, J. [Ontario Power Generation, Ontario (Canada); Taylor, D. [New Brunswick Power, Fredericton, New Brunswick (Canada); Zemdegs, R. [Candu Energy Inc., Mississauga, Ontario (Canada); Kapaklili, T. [CANDU Owner' s Group, Toronto, Ontario (Canada); Balog, G. [AMEC NSS, Ontario (Canada); Kozluk, M. [Independent Consultant (Canada); Oliva, A. [Candesco, Ontario (Canada)

    2011-07-01

    The Canadian CANDU Industry is implementing a composite analytical solution to demonstrate, with high confidence, adequate safety margins for Large Break Loss of Coolant Accidents (LBLOCA) in existing CANDU reactors. The approach involves consolidating a number of individual approaches in a manner that alleviates reliance on any single analytical method or activity. Using a multi-layered approach, the objective of this composite solution is to use a variety of reinforcing analytical approaches such that they complement one another to collectively form a robust solution. The composite approach involves: i) systematic reclassification of LBLOCA to beyond design basis events based on the frequency of the limiting initiating events; ii) more realistic modeling of break opening characteristics; iii) application of Best Estimate and Uncertainty (BEAU) analysis methodology to provide a more realistic representation of the margins; iv) continued application of Limit of Operating Envelope (LOE) methodology to demonstrate the adequacy of margins at the extremes of the operating envelope; v) characterizing the coolant void reactivity, with associated uncertainties; and vi) defining suitable acceptance criteria, accounting for the available experimental database and uncertainties. The approach is expected to confirm the adequacy of existing design provisions and, as such, better characterize the overall safety significance of LBLOCA in CANDU reactors. This paper describes the composite analytical approach and its development, implementation and current status. (author)

  10. Revisiting large break LOCA with the CATHARE-3 three-field model

    Energy Technology Data Exchange (ETDEWEB)

    Valette, Michel, E-mail: michel.valette@cea.fr [CEA Grenoble, 17, rue des Martyrs, 38054 Grenoble Cedex 9 (France); Pouvreau, Jerome, E-mail: jerome.pouvreau@cea.fr [CEA Grenoble, 17, rue des Martyrs, 38054 Grenoble Cedex 9 (France); Bestion, Dominique, E-mail: dominique.bestion@cea.fr [CEA Grenoble, 17, rue des Martyrs, 38054 Grenoble Cedex 9 (France); Emonot, Philippe, E-mail: philippe.emonot@cea.fr [CEA Grenoble, 17, rue des Martyrs, 38054 Grenoble Cedex 9 (France)

    2011-11-15

    Highlights: Black-Right-Pointing-Pointer CATHARE 3 enables a three-field analysis of a LB LOCA. Black-Right-Pointing-Pointer Reflooding experiments in isolated rod bundles are satisfactory predicted. Black-Right-Pointing-Pointer A BETHSY integral test simulation supports the CATHARE 3 3-field assessment. - Abstract: Some aspects of large break LOCA analysis (steam binding, oscillatory reflooding, top-down reflooding) are expected to be improved in advanced system codes from more detailed description of flows by adding a third field for droplets. The future system code CATHARE-3 is under development by CEA and supported by EDF, AREVA-NP and IRSN in the frame of the NEPTUNE project and this paper shows some preliminary results obtained in reflooding conditions. A three-field model has been implemented, including vapor, continuous liquid and liquid droplet fields. This model features a set of nine equations of mass, momentum and energy balance. Such a model allows a more detailed description of the droplet transportation from core to steam generator, while countercurrent flow of continuous liquid is allowed. Code assessment against reflooding experiments in a rod bundle is presented, using 1D meshing of the bundle. Comparisons of CATHARE-3 simulations against data series from PERICLES and RBHT full scale experiments show satisfactory results. Quench front motions are well predicted, as well as clad temperatures in most of the tested runs. The BETHSY 6.7C Integral Effect Test simulating the gravity driven reflooding process in a scaled PWR circuit is then compared to CATHARE-3 simulation. The three-field model is applied in several parts of the circuit: core, upper plenum, hot leg and steam generator, represented by either 1D or 3D modules, while the classic six-equation model is used in the other parts of the loop. An analysis of these first results is presented and future work is defined for improving the droplet behavior simulation in both the upper plenum and the

  11. 船用堆大破口失水事故放射性后果分析%Radioactive Consequence Analysis on Large-break LOCA of Marine Reactor

    Institute of Scientific and Technical Information of China (English)

    王伟; 陈力生; 张帆; 刘海鹏

    2015-01-01

    Based on the severe accident analysis program MELCOR as computational tool ,computational model of the marine reactor was established in the paper .Both the source behavior and radioactive consequence were researched when the double‐ended rupture large‐break LOCA happened on the cold leg of a typical ship reactor . T he release ,migration and reactor cabin distribution of the noble gas and CsI were analyzed , and the plunge criterion of ventilation system was researched .The results show that in order to assure the radiation dose of the cabin adjacent reactor cabin in the dose limits , the whole ship ventilation system should be plunged within 10 min after the accident . Otherwise ,the protective measure should be used before the whole body dose and thyroid dose reach the dose limits .%本文以严重事故分析程序M ELCOR为计算工具,建立了某型船用堆的计算模型,研究了某型船用堆发生冷段双端断裂大破口失水事故的源项行为及放射性后果。分析了惰性气体Xe与挥发性气体CsI的释放、迁移和舱室分布规律,并对通风系统投入时机进行研究。结果表明:为保证堆舱临舱的剂量辐射在剂量限值内,应于事故发生后10 min内投入全船通风。否则,应于全身剂量和甲状腺剂量达到剂量限值前及时采取防护措施。

  12. Scientific design of the test facility for the KNGR DVI line small break LOCA

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Byong Jo; Park, Choon Kyung; Jun, Hyung Gil; Cho, Seok; Kwon, Tae Soon; Song, Chul Hwa; Kim, Jung Taek

    1999-03-01

    Scientific design of the experimental facility (OASIS) for the KNGR (Korea Next Generation Reactor) DVI line SB-LOCA simulation is carried out. Main purpose of the OASIS is to produce thermal-hydraulic data base for determining the best location of the DVI (Direct Vessel Injection) injection nozzle of the KNGR as well as verifying its design performance in view of the ECCS (Emergency Core Cooling System) effectiveness. The experimental facility is designed based on the Ishii's three-level scaling law. The facility has 1/4 height and 1/341 area scaling ratio. It corresponds to the volume scale of 1/1364. The power scaling is 1/682 and the system pressure is prototypic. The OASIS consists of a core, a downcomer, two steam generators, two pump simulators, a break simulator, a collection tank, primary piping as well as a circulation pump for initial test condition. Each component is designed based on the Ishill's global scaling and boundary flow scaling of mass, energy and momentum. In addition, local phenomena scaling is carried out for the design of major components to preserve key local phenomena in each component. Most of the key phenomena are well preserved in the OASIS. However, the local scaling analysis shows that distortions of the void fraction and mixture level can not be avoided in the core. It comes from the basic features of the Ishill's scaling law in case of the reduced-height simulation. However, it is expected that these distortions will be analyzed properly by a best estimate system analysis code. (Author). 22 refs., 20 tabs., 25 figs.

  13. APT Blanket System Loss-of-Coolant Accident (LOCA) Analysis Based on Initial Conceptual Design - Case 3: External HR Break at Pump Outlet without Pump Trip

    Energy Technology Data Exchange (ETDEWEB)

    Hamm, L.L.

    1998-10-07

    This report is one of a series of reports that document normal operation and accident simulations for the Accelerator Production of Tritium (APT) blanket heat removal (HR) system. These simulations were performed for the Preliminary Safety Analysis Report.

  14. Multi-dimensional LOCA Analysis, Status and Perspective

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Yong [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

    2015-10-15

    The most extensive research project for LOCA was the 2D/3D program. It involved large or full size experiments such as CCTF (Cylindrical Core Test Facility), SCTF (Slab Core Test Facility) and UPTF (Upper Plenum Test Facility) as well as the most up-to-date two-fluid analysis code, TRAC. With the background of 2D/3D study, the topic of this paper is to investigate facts concerning LOCA application of the present day up-to-date code systems such as RELAP5, TRAC, CATHARE and COBRA-TF. Especially, focus has been put on the multi-dimensional phenomena. The rigorous conservative form of COBRA-TF is strongly recommended to handle the multi-dimensional multi-phase flow phenomena in the future. It is inevitable to develop the reasonable correlation for the covariance coefficients.

  15. Analysis of LOCA Scenarios in the NIST Research Reactor Before and After Fuel Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Baek, J. S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Cheng, L. Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Diamond, D. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-08-30

    An analysis has been done of hypothetical loss-of-coolant-accidents (LOCAs) in the research reactor (NBSR) at the National Institute of Standards and Technology (NIST). The purpose of the analysis is to determine if the peak clad temperature remains below the Safety Limit, which is the blister temperature for the fuel. The configuration of the NBSR considered in the analysis is that projected for the future when changes will be made so that shutdown pumps do not operate when a LOCA signal is detected. The analysis was done for the present core with high-enriched uranium (HEU) fuel and with the proposed low-enriched uranium (LEU) fuel that would be used when the NBSR is converted from one to the other. The analysis consists of two parts. The first examines how the water would drain from the primary system following a break and the possibility for the loss of coolant from within the fuel element flow channels. This work is performed using the TRACE system thermal-hydraulic code. The second looks at the fuel clad temperature as a function of time given that the water may have drained from many of the flow channels and the water in the vessel is in a quasi-equilibrium state. The temperature behavior is investigated using the three-dimensional heat conduction code HEATING7.3. The results in all scenarios considered for both HEU and LEU fuel show that the peak clad temperature remains below the blister temperature.

  16. Parametric study on effect of break size during LOCA on thermal hydraulic conditions in an indian pressurized heavy water reactor (220 MWe)

    Energy Technology Data Exchange (ETDEWEB)

    Rao, G.S.; Gupta, S.K.; Raj, V.V. [Bhabha Atomic Research Centre, Mumbai (India)

    1999-07-01

    Loss Of Coolant Accident (LOCA) in a Pressurized Heavy Water Reactor (PHWR) leads to coolant expulsion in a primary heat transport system resulting in depressurization and possible core voiding. This results in deterioration of cooling conditions in reactor channels and increase in power before reactor shutdown, leading to higher fuel temperatures. Coolant expulsion rates during LOCA are dictated by critical flow conditions governed by initial plant conditions prior to the accident, break geometry, location of break, etc. In addition the PHWRs have positive void-coefficient of reactivity for coolant resulting in reactor power rise in earlier part of LOCA, when the stored heat of the fuel has yet not been removed. If, in addition, heat transfer to the coolant drops sharply very high fuel surface temperatures are expected. The paper describes analyses carried out for three different break sizes. (author)

  17. Sensitivity Analyses in Small Break LOCA with HPI-Failure: Effect of Break-Size in Secondary-Side Depressurization

    Science.gov (United States)

    Kinoshita, Ikuo; Torige, Toshihide; Yamada, Minoru

    2014-06-01

    In the case of total failure of the high pressure injection (HPI) system following small break loss of coolant accident (SBLOCA) in pressurized water reactor (PWR), the break size is so small that the primary system does not depressurize to the accumulator (ACC) injection pressure before the core is uncovered extensively. Therefore, steam generator (SG) secondary-side depressurization is necessary as an accident management in order to grant accumulator system actuation and core reflood. A thermal-hydraulic analysis using RELAP5/MOD3 was made on SBLOCA with HPI-failure for Oi Units 3/4 operated by Kansai Electoric Power Co., which are conventional 4 loop PWR plants. The effectiveness of SG secondary-side depressurization procedure was investigated for the real plant design and operational characteristics. The sensitivity analyses using RELAP5/MOD3.2 showed that the accident management was effective for a wide range of break sizes, various orientations and positions. The critical break can be 3 inch cold-leg bottom break.

  18. Comparative Experiments to Assess the Effects of Accumulator Nitrogen Injection on Passive Core Cooling During Small Break LOCA

    Directory of Open Access Journals (Sweden)

    Li Yuquan

    2017-02-01

    Full Text Available The accumulator is a passive safety injection device for emergency core cooling systems. As an important safety feature for providing a high-speed injection flow to the core by compressed nitrogen gas pressure during a loss-of-coolant accident (LOCA, the accumulator injects its precharged nitrogen into the system after its coolant has been emptied. Attention has been drawn to the possible negative effects caused by such a nitrogen injection in passive safety nuclear power plants. Although some experimental work on the nitrogen injection has been done, there have been no comparative tests in which the effects on the system responses and the core safety have been clearly assessed. In this study, a new thermal hydraulic integral test facility—the advanced core-cooling mechanism experiment (ACME—was designed and constructed to support the CAP1400 safety review. The ACME test facility was used to study the nitrogen injection effects on the system responses to the small break loss-of-coolant accident LOCA (SBLOCA transient. Two comparison test groups—a 2-inch cold leg break and a double-ended direct-vessel-injection (DEDVI line break—were conducted. Each group consists of a nitrogen injection test and a nitrogen isolation comparison test with the same break conditions. To assess the nitrogen injection effects, the experimental data that are representative of the system responses and the core safety were compared and analyzed. The results of the comparison show that the effects of nitrogen injection on system responses and core safety are significantly different between the 2-inch and DEDVI breaks. The mechanisms of the different effects on the transient were also investigated. The amount of nitrogen injected, along with its heat absorption, was likewise evaluated in order to assess its effect on the system depressurization process. The results of the comparison and analyses in this study are important for recognizing and understanding the

  19. Post-test thermal-hydraulic analysis of two intermediate LOCA tests at the ROSA facility including uncertainty evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Freixa, J., E-mail: jordi@freixa.net [Paul Scherrer Institut (PSI) 5232 Villigen PSI (Switzerland); Kim, T.-W. [Paul Scherrer Institut (PSI) 5232 Villigen PSI (Switzerland); Manera, A. [University of Michigan, Ann Arbor, MI 48109 (United States)

    2013-11-15

    The OECD/NEA ROSA-2 project aims at addressing thermal-hydraulic safety issues relevant for light water reactors by building up an experimental database at the ROSA Large Scale Test Facility (LSTF). The ROSA facility simulates a PWR Westinghouse design with a four-loop configuration and a nominal power of 3423 MWth. Two intermediate break loss-of-coolant-accident (LOCA) experiments (Tests 1 and 2) have been carried out during 2010. The two tests were analyzed by using the US-NRC TRACE best estimate code, employing the same nodalization previously used for the simulation of small-break LOCA experiments of the ROSA-1 programme. A post-test calculation was performed for each test along with uncertainty analysis providing uncertainty bands for each relevant time trend. Uncertainties in the code modelling capabilities as well as in the initial and boundary conditions were taken into account, following the guidelines and lessons learnt through participation in the OECD/NEA BEMUSE programme. Two different versions of the TRACE code were used in the analysis, providing a qualitatively good prediction of the tests. However, the uncertainty analysis revealed differences between the performances of some models in the two versions. The most relevant parameters of the two experimental tests were falling within the computed uncertainty bands.

  20. Post-test thermal-hydraulic analysis of two intermediate LOCA tests at the ROSA facility including uncertainty evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Freixa, J.; Kim, T-W.; Manera, A. [Paul Scherrer Inst., Villigen (Switzerland)

    2011-07-01

    The OECD/NEA ROSA-2 project aims at addressing thermal-hydraulic safety issues relevant for light water reactors by building up an experimental database at the ROSA Large Scale Test Facility (LSTF). The ROSA facility simulates a PWR Westinghouse design with a four-loop configuration and a nominal power of 3423 MWth. Two intermediate break loss-of-coolant-accident (LOCA) experiments (Test 1 and 2) have been carried out during 2010. The two tests were analyzed by using the US-NRC TRACE best estimate code, employing the same nodalization previously used for the simulation of small-break LOCA experiments of the ROSA-1 program. A post-test calculation was performed for each test along with uncertainty analysis providing uncertainty bands for each relevant time trend. Uncertainties in the code modeling capabilities as well as in the initial and boundary conditions were taken into account, following the guidelines and lessons learnt through participation in the OECD/NEA BEMUSE program. Two different versions of the TRACE code were used in the analysis, providing a qualitatively good prediction of the tests. However, both versions showed deficiencies that need to be addressed. The most relevant parameters of the two experimental tests were falling within the computed uncertainty bands. (author)

  1. Thermal fluid mixing behavior during medium break LOCA in evaluation of pressurized thermal shock

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Jae Won; Bang, Young Seok; Seul, Kwang Won; Kim, Hho Jung [Korea Institute of Nuclear Safety, Taejon (Korea, Republic of)

    1998-12-31

    Thermal fluid mixing behavior during a postulated medium-size hot leg break loss of coolant accident is analyzed for the international comparative assessment study on pressurized thermal shock (PTS-ICAS) proposed by OECD-NEA. The applicability of RELAP5 code to analyze the thermal fluid mixing behavior is evaluated through a simple modeling relevant to the problem constraints. Based on the calculation result, the onset of thermal stratification is investigated using Theofanous`s empirical correlation. Sensitivity calculations using a fine node model and crossflow model are also performed to evaluate the modeling capability on multi-dimensional characteristics related to thermal fluid mixing. 6 refs., 8 figs. (Author)

  2. Experimental simulation of asymmetric heat up of coolant channel under small break LOCA condition for PHWR

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Ashwini K., E-mail: ashwinikumaryadav@gmail.com [Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee 247667 (India); Majumdar, P., E-mail: pmajum@barc.gov.in [Reactor Safety Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kumar, Ravi, E-mail: ravikfme@iitr.ernet.in [Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee 247667 (India); Chatterjee, B., E-mail: barun@barc.gov.in [Reactor Safety Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Gupta, Akhilesh, E-mail: akhilfme@iitr.ernet.in [Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee 247667 (India); Mukhopadhyay, D., E-mail: dmukho@barc.gov.in [Reactor Safety Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2013-02-15

    Highlights: ► Circumferential temperature gradient of PT for asymmetric heat-up was 440 °C. ► At 2 MPa ballooning initiated at 450 °C and with strain rate of 0.0277%/s. ► At 4 MPa ballooning initiated at 390 °C and with strain rate of 0.0305%/s. ► At 4 MPa, PT ruptured under uneven strain and steep temperature gradient. ► Integrity of PT depends on internal pressure and magnitude of decay power. -- Abstract: During postulated small break loss of coolant accident (SBLOCA) for Pressurised Heavy Water Reactors (PHWRs) as well as for postulated SBLOCA coincident with loss of ECCS, a stratified flow condition can arise in the coolant channels as the gravitational force dominates over the low inertial flow arising from small break flow. A Station Blackout condition without operator intervention can also lead to stratified flow condition during a slow channel boil-off condition. For all these conditions the pressure remains high and under stratified flow condition, the horizontal fuel bundles experience different heat transfer environments with respect to the stratified flow level. This causes the bundle upper portion to get heated up higher as compared to the submerged portion. This kind of asymmetrical heating of the bundle is having a direct bearing on the circumferential temperature gradient of pressure tube (PT) component of the coolant channel. The integrity of the PT is important under normal conditions as well as at different accident loading conditions as this component houses the fuel bundles and serves as a coolant pressure boundary of the reactors. An assessment of PT is required with respect to different accident loading conditions. The present investigation aims to study thermo-mechanical behaviour of PT (Zr, 2.5 wt% Nb) under a stratified flow condition under different internal pressures. The component is subjected to an asymmetrical heat-up conditions as expected during the said situation under different pressure conditions which varies from 2

  3. CATHARE2 calculation of SPE-3 test small break loca on PMK facility

    Energy Technology Data Exchange (ETDEWEB)

    Laugier, E.; Radet, J. [Institut de Protection et de Surete Nucleaire, Cadarache (France)

    1995-09-01

    Bind and post test calculations with CATHARE2 have been performed concerning the SPE-4 exercise organized under the auspices of IAEA on the hungarian PMK-2 facility, a one loop scaled model of VVER 440/213 Nuclear Power Plant. The SPE-4 test is a cold leg SBLOCA associated to a {open_quotes}bleed and feed{close_quotes} procedure applied in the secondary circuit. The present paper is devoted to the analysis of the post test calculation. For the first part of the transient (until the end of the SIT activations), the primary and secondary pressures are rather well predicted, leading to a good agreement with the experimental trips, as scram, flow coast down, SIT beginning and end of activation. Nevertheless, some discrepancy with the experiment may be due to an over prediction of the thermal exchanges from the primary to the secondary circuits. For the second part of the transient, the predicted primary circuit repressurization is shifted after the SITs are off, while in the experiment this event immediately follows the end of SIT activation. The delay in the calculation leads to underpredict primary and secondary pressures, thus anticipating the timing of events, such as LPIS and emergency feedwater activation.

  4. Severe accident analysis of a small LOCA accident using MAAP-CANDU support level 2 PSA for the Point Lepreau station refurbishment project

    Energy Technology Data Exchange (ETDEWEB)

    Petoukhov, S.M.; Brown, M.J.; Mathew, P.M. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    2012-07-01

    A Level 2 Probabilistic Safety Assessment was performed for the Point Lepreau Generating Station. The MAAP4-CANDU code was used to calculate the progression of postulated severe core damage accidents and fission product releases. Five representative severe core damage accidents were selected: Station Blackout, Small Loss-of-Coolant Accident, Stagnation Feeder Break, Steam Generator Tube Rupture, and Shutdown State Accident. Analysis results for only the reference Small LOCA Accident scenario (which is a very low probability event) are discussed in this paper. (author)

  5. Dynamic event Tress applied to sequences Full Spectrum LOCA. Calculating the frequency of exceedance of damage by integrated Safety Analysis Methodology; Arboles de sucesos dinamicos aplicados a secuencias Full Spectrum LOCA. Calculo de la frequencia de excedencia del dano mediante la metodologia Analisis Integrados de Seguridad (ISA)

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Magan, J. J.; Fernandez, I.; Gil, J.; Marrao, H.; Queral, C.; Gonzalez-Cadelo, J.; Montero-Mayorga, J.; Rivas, J.; Ibane-Llano, C.; Izquierdo, J. M.; Sanchez-Perea, M.; Melendez, E.; Hortal, J.

    2013-09-01

    The Integrated Safety Analysis (ISA) methodology, developed by the Spanish Nuclear Safety council (CSN), has been applied to obtain the dynamic Event Trees (DETs) for full spectrum Loss of Coolant Accidents (LOCAs) of a Westinghouse 3-loop PWR plant. The purpose of this ISA application is to obtain the Damage Exceedance Frequency (DEF) for the LOCA Event Tree by taking into account the uncertainties in the break area and the operator actuation time needed to cool down and de pressurize reactor coolant system by means of steam generator. Simulations are performed with SCAIS, a software tool which includes a dynamic coupling with MAAP thermal hydraulic code. The results show the capability of the ISA methodology to obtain the DEF taking into account the time uncertainty in human actions. (Author)

  6. SCDAP/RELAP5 analysis of station blackout with pump seal LOCA in Surry plant

    Energy Technology Data Exchange (ETDEWEB)

    Hidaka, Akihide; Soda, Kunihisa; Sugimoto, Jun [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1995-06-01

    During a station blackout of PWR, the pump seal will fail due to loss of the seal cooling. This particular transient-LOCA sequence designated as S3-TMLB` analyzed by SNL with MELPROG/TRAC for Surry plant showed that the depressurization due to the pump seal LOCA would result in early accumulator injection and subsequent core cooling which lead to the delay of reactor pressure vessel (RPV) meltthrough. The present analysis was performed with SCDAP/RELAP5 to evaluate this scenario shown in the MELPROG/TRAC analyses. Additionally, the calculated results were compared with the similar experimental studies of JAERI`s ROSA-IV program. The present analyses showed that: (1) During S3-TMLB`, the loop seal clearing would occur and cause a slight delay of accident progression. (2) It is unlikely that the accumulator injection, which leads to the delay of RPV meltthrough by approximately 60 min, is initiated automatically during S3-TMLB`. Accordingly, an intentional depressurization using PORVs is recommended for the mitigation of the accident consequences. (3) The present SCDAP/RELAP5 analyses did not show significant delay of accident progression. It was found that non-realistic lower heat generation and higher core cooling models used in the MELPROG/TRAC analysis are attributed to this discrepancy. (author).

  7. Research on the improvement of nuclear safety -The development of LOCA analysis codes for nuclear power plant-

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Won Pyo; Jung, Yung Jong; Kim, Kyung Doo; Jung, Jae Joon; Kim, Won Suk; Han, Doh Heui; Hah, Kooi Suk; Jung, Bub Dong; Lee, Yung Jin; Hwang, Tae Suk; Lee, Sang Yong; Park, Chan Uk; Choi, Han Rim; Lee, Sang Jong; Choi, Jong Hoh; Ban, Chang Hwan; Bae, Kyoo Hwan [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1995-07-01

    The present research aims at development of both a best estimate methodology on LOCA analysis and, as an application, performance analyses of safety systems. SBLOCA analyses have been continued to examine the capacity reduction effect of ECCS since the second project year. As a results, core uncovery, which is requirement of URD has not been occurred in 6`` cold leg break. Although core uncovery has been predicted when DVI line has been broken for DVI+4-Train HPIS, the calculated PCT has lied well within the criterion. The effect of safety injection position and SIT characteristics are also analyzed for LBLOCA. The results show that cold leg injection is the most effective way and the adaption of advanced SIT could lead to elimination of LPSI pump from the safety system. On the other hand, the quantified uncertainties obtained from THTF and FLECHT/SEASET which represents blowdown and reflood phenomena, respectively, have been confirmed using IET(LOFT test). The application uncertainty for Kori unit 3 has been analyzed. Finally, application of the best estimate methodology using the uncertainties concerned with the code, the bais, and the application, leads to overall uncertainty of about 200K for Kori unit 3. 244 figs, 22 tabs, 92 refs. (Author).

  8. Analysis of Post-LOCA Core Inlet Blockage to Evaluate In-vessel Downstream Effect in APR1400

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Young Seok [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2015-10-15

    The method was developed to have a conservatism to cover the uncertainty of analysis and the acceptance is judged by the representative bounding estimation. However, the important safety parameters such as the available driving head need to be confirmed by the plant specific calculation. Also an interaction between the debris induced head loss and the core flow rate needs to be explained because the head loss induced by debris in actual condition may reduce the core inflow rate faster. To confirm the safety parameters, in this study, thermal-hydraulic response considering the core inlet blockage (CIB) by debris during LTCC process following a double-ended guillotine break of cold leg (CLB), one of hot leg (HLB) and one of intermediate leg (ILB) of the APR1400 were calculated, respectively. MARS-KS 1.3 code has been used. The CIB has been modeled by the closure of valves to the core in exponential manner with time to observe the behavior near the complete blockage. To understand the effect of core inlet blockage (CIB) during a long term core cooling (LTCC) phase following a loss-of-coolant accident (LOCA) in the light of in-vessel downstream effect (IDE) of Generic Safety Issue (GSI) 191, double-ended guillotine break of hot leg (HLB), one of cold leg (CLB) and one of intermediate leg (ILB) were calculated, respectively. And the important safety parameters such as the available driving head and the head loss due to debris were calculated using MARS-KS code and discussed in comparison with the WCAP method. As a result, a little delayed heatup behavior of the fuel cladding was found for all the cases, which due to the redistribution of flow within the core after blockage.

  9. Signal processing system design for improved shutdown system of CANDU{sup ®} nuclear reactors in large break LOCA events

    Energy Technology Data Exchange (ETDEWEB)

    Gabbar, Hossam A., E-mail: hossam.gabbar@uoit.ca [Faculty of Energy Systems and Nuclear Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, ON, Canada L1H 7K4 (Canada); Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, ON, Canada L1H 7K4 (Canada); Xia, Lingzhi; Isham, Manir U. [Faculty of Energy Systems and Nuclear Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, ON, Canada L1H 7K4 (Canada); Ponomarev, Vladimir [Megawatt Solutions, 1235 Radom St., unit 68, Pickering, ON, Canada L1W 1J3 (Canada)

    2016-03-15

    Highlights: • Neutronic signal processing system design to improve CANDU SDS1 performance. • Reactor modeling for CANDU LLOCA transient. • MATLAB/Simulink system implementation for the SDS1 trip logic. • Increasing the SDS1 trip response. - Abstract: For CANDU reactors, several options to improve CANDU nuclear power plant operation safety margin have been investigated in this paper. A particular attention is paid to the response time of CANDU shutdown system number 1 (SDS1) in case of large break loss of coolant accident (LLOCA). Based on point kinetic method, a systematic fundamental analysis is performed to CANDU LLOCA event, and the power transient signal is generated. In order to improve the SDS1 response time during LLOCA events, an innovative power measurement and signal processing system is particularly designed. The new signal processing system is implemented with the input of the LLOCA power transient, and the simulation results of the reactor trip time and signal are compared to those of the existing system in CANDU power plants. It is demonstrated that the new signal processing system can not only achieve a shorter reactor trip time than the existing system, but also accommodate the spurious trip immunity. This will significantly enhance the safety margin for the power plant operation, or bring extra economical benefits to the power plant units.

  10. Effect of fuel pin ballooning on the sub-channel thermal hydraulics during small break loca for Indian PHWRS

    Energy Technology Data Exchange (ETDEWEB)

    Mukhopadhyay, D.; Behera, G.H.; Bandopadhyay, S.K.; Gupta, S.K. [Bhabha Atomic Research Centre, Div. Reactor Safety, Bombay (India)

    2001-07-01

    Effect of fuel pin ballooning on the subchannel thermal-hydraulics during a small break (0.25%) located at the Reactor Inlet Feeder (RIF) has been studied for Indian PHWRs. The break leads to a low flow situation in the affected reactor channel along with delayed reactor trip. Higher power to flow ratio in the inner subchannels in comparison to outer subchannel of a 19 pin fuel bundle causes early 2-phase condition causing the flow to by pass from the inner ones to outer ones. This causes the fuel pins to experience different temperatures. Fuel pin ballooning causes reduction in the subchannel areas and further flow redistribution takes place. The transient subchannel thermal-hydraulic conditions along the reactor channel are very much different due to the power distribution and pressure drop. (authors)

  11. Atmospheric Dispersion Research of Mid-break LOCA for Small Reactor of Nuclear-powered Device in Dock%小型动力堆码头中破口失水事故大气扩散研究

    Institute of Scientific and Technical Information of China (English)

    王伟; 张帆; 陈力生; 晏峰

    2014-01-01

    Using the model of Gaussion subsection plume ,the radioactive nuclide atmos‐pheric dispersion rule in the terrain of 20 km of the coastal w as estimated w hen the design basis accident with 29.4% equivalent diameter break size happened .The source term was captured by the calculation program of severe accident named MELCOR ,and the result was used as input in the analysis software of atmospheric dispersion named MACCS .The results show that the mid‐break LOCA would lead to the radioactive pol‐lution for the area of dock .The slower the wind blows and the more steady the weather is ,the larger the radioactive polluted area is .%采用高斯分段烟羽模型估算了某小型动力堆在码头内发生破口尺寸为29.4%当量直径的设计基准事故时,放射性核素在码头20 km 区域范围内的大气扩散规律。源项采用严重事故计算程序M ELCOR仿真获得,并将计算结果输入到大气扩散分析软件M ACCS进行分析计算。计算结果表明:中破口失水事故会造成码头区域的放射性污染,风速越小、气象条件越稳定,放射性的影响范围越大。

  12. Large break loss-of-coolant accident analysis for China Qinshan-2 nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Yong; Ban, Chang Hwan; Chung, Bub Dong [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Wang, Rongzhong; Yu, Hongxing [Nuclear Power Institute of China, Chengdu, SC (China)

    1994-12-01

    Large break LOCA analysis for China Qinshan-2 nuclear power plant has been performed using realistic evaluation model which has been being developed by KAERI. RELAP5/MOD3/KAERI code, which is a modified version of RELAP5/MOD3, is coupled with CONTEMPT4/MOD5 and is used as a best estimate code to predict the thermal hydraulic behavior of the system. PCT uncertainty which stems from code uncertainty, plant application uncertainty, scaling uncertainty and PCT bias are discussed. Among them, plant application uncertainty is described in detail. The licensing PCT is calculated by adding all the uncertainties to the best-estimate PCT. The result indicates the Qinshan-2 nuclear power plant has at least 37 deg C safety margin for large break LOCA. (Author) 10 refs., 47 figs., 14 tabs.

  13. Comparison of CATHARE results with the experimental results of cold leg intermediate break LOCA obtained during ROSA-2/LSTF test 7

    Directory of Open Access Journals (Sweden)

    Mazgaj Piotr

    2016-01-01

    Full Text Available Thermal-hydraulic analysis is a key part in support of regulatory work and nuclear power plant design and operation. In the field of Loss Of Coolant Accident, evolutions of the regulations are discussed in various countries taking into account the very unlikely character of a double-ended guillotine break and questioning the necessity to study such an event with Design Basis Conditions assumptions. As a consequence, the consideration of intermediate size piping rupture becomes more and more important. The paper presents the modeling of the Test Facility ROSA-2/LSTF in the calculation code CATHARE 2.V2.5. OECD/NEA ROSA-2 Project Test 7 was conducted with the Large Scale Test Facility on June 14, 2012. The experiment simulated the thermal-hydraulic responses during a PWR 13% cold leg Intermediate Break Loss Of Coolant Accident (IBLOCA. The break was simulated by a cold leg upwardly mounted long break nozzle. The facility and the experiment conditions are modeled in CATHARE. The vessel is modeled by using a 3D module. A thermal-hydraulic analysis is conducted and the obtained results are subsequently compared with the experimental results from ROSA-2/LSTF Test 7. Evaluation of the differences between experimental and calculated results is discussed.

  14. A Stylistic Analysis of Break,Break,Break

    Institute of Scientific and Technical Information of China (English)

    李瑶

    2015-01-01

    Break, Break, Break is a poem by Alfred Lord Tennyson, the Poet Laureate during the Queen Victoria's reign. This exquisite little poem is wel known for the poet's grief-stricken feelings and heart-broken emotions over the premature death of his best friend, Arthur Henry Halam. Most of the previous studies on this poem focus on the emotional level to consider it as an elegy, expressing sorrow and lamentation for the death of a particular person. However, in order to have a deep understanding in general, this paper analyzes the poem based on the stylistic theory, concerning on the lexical level and the semantic level. It aims at helping the readers to cultivate a sense of appropriateness, to sharpen the understanding and appreciation of literary works and to achieve adaptation in translation.

  15. Comparison of CATHARE results with the experimental results of cold leg intermediate break LOCA obtained during ROSA-2/LSTF test 7

    OpenAIRE

    2016-01-01

    Thermal-hydraulic analysis is a key part in support of regulatory work and nuclear power plant design and operation. In the field of Loss Of Coolant Accident, evolutions of the regulations are discussed in various countries taking into account the very unlikely character of a double-ended guillotine break and questioning the necessity to study such an event with Design Basis Conditions assumptions. As a consequence, the consideration of intermediate size piping rupture becomes more and more i...

  16. Analysis of a LOCA in the vapor line of an ESBWR with reduced order models; Analisis de un LOCA en la linea de vapor de un ESBWR con modelos de orden reducido

    Energy Technology Data Exchange (ETDEWEB)

    Barron A, I.; Morales S, J. [Facultad de Ingenieria, Division de Estudios de Posgrado, UNAM, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)], e-mail: isbarron@gmail.com

    2009-10-15

    The present work shows the analysis of an accident with loss of coolant, LOCA, in the vapor line of economic and simplified boiling water reactor, ESBWR, with reduced order models. The basic understanding of the main phenomena is the benefit of use of reduced order models, being obtained and approximate answer with regard to codes of better estimate. The state equations were identified for the regions in that the vessel is divided, the plant balance and contention, allowed to propose reduced order models programmed in Simulink of Matlab. These models allowed to obtain values of variables involved in the stable state and during a transitory as the accident with lost of coolant, with an error margin according to the type of reduced order models employees.

  17. Design basis neutronics calculations for NRU-LOCA experiments

    Energy Technology Data Exchange (ETDEWEB)

    Heaberlin, S.W.; Jenquin, U.P.; McNair, G.W.; Perry, R.T.; Trapp, T.J.; Zimmerman, M.G.

    1979-08-01

    The report describes the neutronics analysis for the LOCA simulation experiments in the NRU reactor. The experimental program will provide greater understanding of nuclear fuel assembly behavior during the heatup, reflood and quench sequence of a hypothetical LOCA. The decay heat and stored heat, which are the energy source in a LOCA will be simulated by fission heat provided by the NRU reactor. The reactor, the test and test operation are described.

  18. Modelling the transport of radionuclides released in the Ilha Grande bay (Brazil) after a Large Break Loca ion the primary system of a PWR

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Andre Silva de; Simoes Filho, Francisco Fernando Lamego; Soares, Abner Duarte; Lapa, Celso Marcelo Franklin, E-mail: flamego@ien.gov.b, E-mail: asoares@cnen.gov.b, E-mail: lapa@ien.gov.b [Instituto de Engenharia Nuclear (LIMA/IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2011-07-01

    It was postulated, in the cooling system of the core, a LOCA, where 431 m{sup 3} of soda almost instantaneously was lost. This inventory contained 1.87x10{sup 10} Bq/m{sup 3} of tritium, 2.22x10{sup 7} Bq/m{sup 3} of cobalt,3.48x10{sup 8} Bq/m{sup 3} of cesium and 3.44x10{sup 10} Bq/m{sup 3} of iodine and was released in liquid form near the Itaorna cove, Angra dos Reis - RJ. Applying the model in the proposed scenario (Angra 1 and 2 in operation and Angra 3 progressively reducing the capture and discharge after the accident), the simulated dilution of the specific activity of radionuclide spots, reached values much lower than report levels for seawater (1,1x10{sup 6} Bq/m{sup 3}, 1,11x10{sup 4} Bq/m{sup 3} and 1,85x10{sup 3} Bq/m{sup 3}) after 22 hours, respectively for {sup 3}H, {sup 60}Co, {sup 131}I and {sup 137}Cs. From the standpoint of public exposure to radionuclide dispersion, the results of activity concentration obtained by the model suggest that the observed radiological impact is negligible. Based on these findings, we conclude that there would be no radiological impact related to a further release of controlled effluent discharges into Itaorna cove. (author)

  19. Consistent Posttest Calculations for LOCA Scenarios in LOBI Integral Facility

    Directory of Open Access Journals (Sweden)

    F. Reventós

    2012-01-01

    Full Text Available Integral test facilities (ITFs are one of the main tools for the validation of best estimate thermalhydraulic system codes. The experimental data are also of great value when compared to the experiment-scaled conditions in a full NPP. The LOBI was a single plus a triple-loop (simulated by one loop test facility electrically heated to simulate a 1300 MWe PWR. The scaling factor was 712 for the core power, volume, and mass flow. Primary and secondary sides contained all main active elements. Tests were performed for the characterization of phenomenologies relevant to large and small break LOCAs and special transients in PWRs. The paper presents the results of three posttest calculations of LOBI experiments. The selected experiments are BL-30, BL-44, and A1-84. They are LOCA scenarios of different break sizes and with different availability of safety injection components. The goal of the analysis is to improve the knowledge of the phenomena occurred in the facility in order to use it in further studies related to qualifying nodalizations of actual plants or to establish accuracy data bases for uncertainty methodologies. An example of procedure of implementing changes in a common nodalization valid for simulating tests occurred in a specific ITF is presented along with its confirmation based on posttests results.

  20. Analysis of a LOCA crash into a reactor containment PWR-W with the GOTHIC code; Analisis de un accidente LOCA en contencion de un reactor PWR-W con el codigo GOTHIC

    Energy Technology Data Exchange (ETDEWEB)

    Perianez Alvarez, V.

    2013-07-01

    The main objective of the work is the simulation of a severe accident, type LOCA with the GOTHIC-code, calculations of pressure and temperature in the containment levels, as well as the three-dimensional distribution of the inventory within the containment.

  1. RELAP5 Analyses of ROSA/LSTF Experiments on AM Measures during PWR Vessel Bottom Small-Break LOCAs with Gas Inflow

    Directory of Open Access Journals (Sweden)

    Takeshi Takeda

    2014-01-01

    Full Text Available RELAP5 code posttest analyses were performed on ROSA/LSTF experiments that simulated PWR 0.2% vessel bottom small-break loss-of-coolant accidents with different accident management (AM measures under assumptions of noncondensable gas inflow and total failure of high-pressure injection system. Depressurization of and auxiliary feedwater (AFW injection into the secondary-side of both steam generators (SGs as the AM measures were taken 10 min after a safety injection signal. The primary depressurization rate of 55 K/h caused rather slow primary depressurization being obstructed by the gas accumulation in the SG U-tubes after the completion of accumulator coolant injection. Core temperature excursion thus took place by core boil-off before the actuation of low-pressure injection (LPI system. The fast primary depressurization by fully opening the relief valves in both SGs with continuous AFW injection led to long-term core cooling by the LPI actuation even under the gas accumulation in the SG U-tubes. The code indicated remaining problems in the predictions of break flow rate during two-phase flow discharge period and primary pressure after the gas inflow. Influences of the primary depressurization rate with continuous AFW injection onto the long-term core cooling were clarified by the sensitivity analyses.

  2. ROSA/LSTF experiment report for RUN SB-CL-24 repeated core heatup phenomena during 0.5% cold leg break LOCA

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Mitsuhiro; Anoda, Yoshinari [Department of Reactor Safety Research, Nuclear Safety Research Center, Tokai Research Establishment, Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan)

    2000-03-01

    A small break loss-of-coolant accident (SBLOCA) in a Westinghouse-type four-loop PWR was simulated in an experiment (SB-CL-24) conducted at the Large-Scale Test Facility (LSTF) with an intention to study repeated core heatup during a long-term cooldown process. The experiment was conducted on February 28, 1990 with specified test conditions including failure assumptions both on the high pressure injection (HPI) and the auxiliary feedwater systems, and the intentional secondary system depressurization as an operator action. The secondary depressurization contributed to promote the primary depressurization and the actuation of accumulator injection system (AIS). A temporary core heatup was observed in each of three loopseal clearing (LSC) processes. A significant core heatup occurred in the following boil-off process after loss of the secondary coolant mass and the AIS termination due to increase of the primary pressure. By additional opening of the pressurizer relief valves and safety valves, the primary pressure rapidly decreased to result in the low pressure injection (LPI) which cooled the heated core. This report summarizes results of the experiment (SB-CL-24) in addition to typical responses of some accident indication systems including the core exit thermocouples (CETs) and the water level meters in the primary system. (author)

  3. CATHARE Assessment of PACTEL LOCA Experiments with Accident Management

    Directory of Open Access Journals (Sweden)

    Luben Sabotinov

    2010-01-01

    Full Text Available This paper summarizes the analysis results of three PACTEL experiments, carried out with the advanced thermal-hydraulic system computer CATHARE 2 code as a part of the second work package WP2 (analytical work of the EC project “Improved Accident Management of VVER nuclear power plants” (IMPAM-VVER. The three LOCA experiments, conducted on the Finnish test facility PACTEL (VVER-440 model, represent 7.4% cold leg breaks with combination of secondary bleed and primary bleed and feed and different actuation modes of the passive safety injection. The code was used for both defining and analyzing the experiments, and to assess its capabilities in predicting the associated complex VVER-related phenomena. The code results are in reasonable agreement with the measurements, and the important physical phenomena are well predicted, although still further improvement and validation might be necessary.

  4. APT Blanket System Loss-of-Coolant Accident (LOCA) Based on Initial Conceptual Design - Case 4: External Pressurizer Surge Line Break Near Inlet Header

    Energy Technology Data Exchange (ETDEWEB)

    Hamm, L.L.

    1998-10-07

    This report is one of a series of reports documenting accident scenario simulations for the Accelerator Production of Tritium (APT) blanket heat removal systems. The simulations were performed in support of the Preliminary Safety Analysis Report (PSAR) for the APT.

  5. APT Blanket System Loss-of-Coolant Accident (LOCA) Based on Initial Conceptual Design - Case 1: External HR Break Near Inlet Header

    Energy Technology Data Exchange (ETDEWEB)

    Hamm, L.L.

    1998-10-07

    The APT blanket system has about 57 MW of thermal energy deposited within the blanket region under normal operating conditions from the release of neutrons and the interaction of the High energy particles with the blanket materials. This corresponds to about 48 percent of total thermal energy deposited in the APT target/blanket system. The deposited thermal energy under normal operation conditions is an important input parameter used in the thermal-hydraulic design and accident analysis.

  6. Breaking a magnetic zero locus: asymptotic analysis

    OpenAIRE

    Raymond, Nicolas

    2014-01-01

    25 pages; This paper deals with the spectral analysis of the Laplacian in presence of a magnetic field vanishing along a broken line. Denoting by $\\theta$ the breaking angle, we prove complete asymptotic expansions of all the lowest eigenpairs when $\\theta$ goes to $0$. The investigation deeply uses a coherent states decomposition and a microlocal analysis of the eigenfunctions.

  7. Analysis of the contribution and efficiency of the Santuario de la Naturaleza Yerba Loca, 33º S in protecting the regional vascular plant flora (Metropolitan and Fifth regions of Chile Análisis de la contribución y eficiencia del Santuario de la Naturaleza Yerba Loca, 33º S, en la protección de la flora vascular regional (regiones Metropolitana y Quinta de Chile

    Directory of Open Access Journals (Sweden)

    MARY T. K ARROYO

    2002-12-01

    Full Text Available Santuario de la Naturaleza Yerba Loca (SN Yerba Loca, Metropolitan Region (MR, 33º S, Chile is analyzed for its conservation value and efficiency in protecting native vascular plants in a regional context. The reserve's flora of 500 species and subtaxa was evaluated for species richness, endemism, range size and marginally distributed taxa, using species-area analysis, and tendencies in the floras of the MR (1.434 species and subtaxa and MR-Fifth regions (1,841 species and subtaxa to set the regional pattern. The reserve (0.7 % of MR land area and 0.3 % MR-Fifth land area contains 34 % of the MR and 27% of the MR-Fifth floras, and around 16-17 % of the mediterranean-climate area (regions IV-VIII flora of central Chile. Veech's Relative Richness Index (RRI revealed that SN Yerba Loca houses exaggerated richness in relation to its land area (28 % more species than expected from the regional model. However, endemism rates (35 % Continental Chile endemics, 22 % Mediterranean endemics, 3% MR-Vth endemics are statistically lower than in the MR (44 %, 29 %, 9 % and the MR-Vth (48 %, 31 %, 11 % floras, and SN Yerba Loca houses proportionately fewer MR endemics (2 % than the MR (6 %. Compared with the regional floras, the reserve contains statistically fewer marginally distributed species, and range size (median = five administrative regions is significantly larger. The reserve's outstanding species richness compensates for its low endemism rates bringing the absolute number of endemics to 92 % of the regional expectation. Corresponding values for marginally distributed species are 81 % (northern limits, 63% (southern limits and for median and shorter range taxa, 100 %. It is concluded that SN Yerba Loca is a highly efficient reserve from the point of view of vascular plant conservation, and represents an excellent conservation choice. SN Yerba Loca and MN El Morado (a second state protected area in the MR, conservatively, house 39 % of the native

  8. Progress of LOCA Integrated Test

    Institute of Scientific and Technical Information of China (English)

    XU; Qian; DIAO; Jun-hui; ZHANG; Pei-sheng; JI; Song-tao

    2015-01-01

    Fuel element is the key component of reactor,which is important to reactor safety and stability.As the tough operation condition,cladding material performance is degressive,especially when LOCA occurs,cladding integrate is suffered by high temperature oxidation and hydrogen brittlement."Research on new domestic zircaloy

  9. An Analysis of Break,Break,Break Based on the Stylistic Theory

    Institute of Scientific and Technical Information of China (English)

    李瑶

    2014-01-01

    Break,Break,Break is a poem by Alfred Lord Tennyson, the Poet Laureate during the Queen Victoria's reign. This exquisite little poem is wel known for the poet’s grief-stricken feelings and heart-broken emotions over the premature death of his best friend, Arthur Henry Hal am. Most of the previous studies on this poem focus on the emotional level to consider it as an elegy, expressing sorrow and lamentation for the death of a particular person. However, in order to have a deep understanding in general, this paper analyzes the poem based on the stylistic theory, concerning on the phonological level and the grammatical level. It aims at helping the readers to cultivate a sense of appropriateness, to sharpen the understanding and appreciation of literary works and to achieve adaptation in translation.

  10. Scenarios simulation of severe accident type small loss of coolant (Loca), with the code MELCOR version 2.1 for the nuclear power plant of Laguna Verde; Simulacion de escenarios de accidente severo tipo perdida de refrigerante (Loca) pequeno, con el codigo MELCOR version 2.1 para la central nucleo-electrica de Laguna Verde

    Energy Technology Data Exchange (ETDEWEB)

    Cardenas V, J.; Mugica R, C. A.; Godinez S, V., E-mail: Jaime.cardenas@cnsns.gob.mx [Comision Nacional de Seguridad Nuclear y Salvaguardias, Dr. Jose Ma. Barragan No. 779, Col. Narvarte, 03020 Mexico D. F. (Mexico)

    2013-10-15

    In this work was carried out the analysis of two scenarios of the accident type with loss of coolant in a recirculation loop for a break with smaller ares to 0.1 ft{sup 2} (4.6 cm{sup 2}), which is classified according to their size like small Loca. The first simulated scenario was a small Loca without action of the emergency coolant injection systems, and the second was a small Loca with only the available system LPCS. This design base accident was taken into account for its relevance with regard to the damage to the core and the hydrogen generation. Was also observed and analyzed the response of the action of the ECCS that depend of the loss of coolant reason and this in turn depends of the size and type of the pipe break. The specified scenarios were simulated by means of the use of MELCOR model for the nuclear power plant of Laguna Verde that has the Comision Nacional de Seguridad Nuclear y Salvaguardias. (Author)

  11. LOCA steam condensation loads in BWR Mark II pressure suppression containment system

    Energy Technology Data Exchange (ETDEWEB)

    Kukita, Y.; Namatame, K.; Takeshita, I.; Shiba, M.

    1987-06-01

    Hydrodynamic loads induced in the BWR Mark II pressure suppression containment system during a loss-of-coolant accident (LOCA) were investigated using a large scale test facility. The maximum-bounding loading conditions on the pressure suppression pool-boundary structures were defined by conducting experiments for a wide range of parameters. The maximum-bounding loads occurred when steam, with air concentration less than 1% in weight, was injected at moderate rates (approx. = 30 kg/m/sup 2/.s) into a low-temperature (below 310 K) pool. Such conditions are most likely to be encountered during LOCAs with intermediate break sizes.

  12. 中小破口失水事故现实估算分析%Realistic Analysis of Intermediate and Small LOCA

    Institute of Scientific and Technical Information of China (English)

    余红星; 廖业宏

    2002-01-01

    介绍了以CATHARE和SAHASB计算机程序为基础的中小破口失水事故现实估算方法.在大亚湾1 8个月换料项目中,为了定义失水事故(LOCA)包络线和检查安全裕量,运用此方法进行了计算分析.结果表明,大亚湾核电站采用18个月换料之后,在中小破口失水事故时仍有较大安全裕量.

  13. Numerical analysis of etoposide induced DNA breaks.

    Directory of Open Access Journals (Sweden)

    Aida Muslimović

    Full Text Available BACKGROUND: Etoposide is a cancer drug that induces strand breaks in cellular DNA by inhibiting topoisomerase II (topoII religation of cleaved DNA molecules. Although DNA cleavage by topoisomerase II always produces topoisomerase II-linked DNA double-strand breaks (DSBs, the action of etoposide also results in single-strand breaks (SSBs, since religation of the two strands are independently inhibited by etoposide. In addition, recent studies indicate that topoisomerase II-linked DSBs remain undetected unless topoisomerase II is removed to produce free DSBs. METHODOLOGY/PRINCIPAL FINDINGS: To examine etoposide-induced DNA damage in more detail we compared the relative amount of SSBs and DSBs, survival and H2AX phosphorylation in cells treated with etoposide or calicheamicin, a drug that produces free DSBs and SSBs. With this combination of methods we found that only 3% of the DNA strand breaks induced by etoposide were DSBs. By comparing the level of DSBs, H2AX phosphorylation and toxicity induced by etoposide and calicheamicin, we found that only 10% of etoposide-induced DSBs resulted in histone H2AX phosphorylation and toxicity. There was a close match between toxicity and histone H2AX phosphorylation for calicheamicin and etoposide suggesting that the few etoposide-induced DSBs that activated H2AX phosphorylation were responsible for toxicity. CONCLUSIONS/SIGNIFICANCE: These results show that only 0.3% of all strand breaks produced by etoposide activate H2AX phosphorylation and suggests that over 99% of the etoposide induced DNA damage does not contribute to its toxicity.

  14. Pressure vessel fracture studies pertaining to a PWR LOCA-ECC thermal shock: experiments TSE-3 and TSE-4 and update of TSE-1 and TSE-2 analysis

    Energy Technology Data Exchange (ETDEWEB)

    Cheverton, R.D.; Bolt, S.E.

    1977-11-04

    The LOCA-ECC Thermal Shock Program was established to investigate the potential for flaw propagation in pressurized-water reactor (PWR) vessels during injection of emergency core coolant following a loss-of-coolant accident. Studies thus far have included fracture mechanics analyses of typical PWRs, the design and construction of a thermal shock test facility, determination of material properties for test specimens, and four thermal shock experiments with 0.53-m-OD (21-in.) by 0.15-m-wall (6-in.) cylindrical test specimens. In the first experiment, initiation was not expected and did not occur, although there was a small amount of subcritical crack growth. In the second experiment, initiation of a semicircular flaw took place as expected; the final length along the surface was about four times the initial length, but there was no radial growth. The third and fourth experiments were similar, and the long axial flaw initiated in good agreement with predictions.

  15. Modelling of LOCA Tests with the BISON Fuel Performance Code

    Energy Technology Data Exchange (ETDEWEB)

    Williamson, Richard L [Idaho National Laboratory; Pastore, Giovanni [Idaho National Laboratory; Novascone, Stephen Rhead [Idaho National Laboratory; Spencer, Benjamin Whiting [Idaho National Laboratory; Hales, Jason Dean [Idaho National Laboratory

    2016-05-01

    BISON is a modern finite-element based, multidimensional nuclear fuel performance code that is under development at Idaho National Laboratory (USA). Recent advances of BISON include the extension of the code to the analysis of LWR fuel rod behaviour during loss-of-coolant accidents (LOCAs). In this work, BISON models for the phenomena relevant to LWR cladding behaviour during LOCAs are described, followed by presentation of code results for the simulation of LOCA tests. Analysed experiments include separate effects tests of cladding ballooning and burst, as well as the Halden IFA-650.2 fuel rod test. Two-dimensional modelling of the experiments is performed, and calculations are compared to available experimental data. Comparisons include cladding burst pressure and temperature in separate effects tests, as well as the evolution of fuel rod inner pressure during ballooning and time to cladding burst. Furthermore, BISON three-dimensional simulations of separate effects tests are performed, which demonstrate the capability to reproduce the effect of azimuthal temperature variations in the cladding. The work has been carried out in the frame of the collaboration between Idaho National Laboratory and Halden Reactor Project, and the IAEA Coordinated Research Project FUMAC.

  16. Thermal hydraulic similarity analysis of the integral effect test facility for main steam line break events

    Energy Technology Data Exchange (ETDEWEB)

    Choi, K.Y.; Park, H.S.; Euh, D.J.; Kwon, T.S.; Baek, W.P. [Thermal Hydraulic Safety Research Division Korea Atomic Energy Research Institute 150 Dukjin-Dong, Yusong-Gu, Daejeon 305-353 (Korea, Republic of)

    2005-07-01

    Full text of publication follows: A thermal-hydraulic integral effect test facility, ATLAS (Advanced Thermal-hydraulic Test Loop for Accident Simulation), is being constructed at Korea Atomic Energy Research Institute (KAERI). The ATLAS is a 1/2 reduced height and 1/288 volume scaled test facility based on the design features of the APR1400, an evolutionary pressurized water reactor developed by Korean industry. The ATLAS will be used to get more realistic understanding of the thermal hydraulic phenomena following postulated events and to carry out performance evaluation and safety analysis of the reference plants. The MSLB (Main Steam Line Break) event is one of the representative non-LOCA events and thermalhydraulic phenomena following the event are to be investigated in the ATLAS. In this paper, thermal hydraulic similarity for MSLB events between the ATLAS and the prototype plant, APR1400 is assessed by using the MARS code, which is a multi-dimensional best-estimate thermal hydraulic code being developed by KAERI. Several cases including SLBFPLOOP and SLBFP are taken into account for similarity analysis in this paper. The neutronic effects such as moderator temperature coefficients and doppler reactivity in APR1400 are not considered in this study. The same control logics for the major sequence of events such as reactor trip, turbine trip, valve opening and actuation of the emergency cooling system are applied to the ATLAS and the APR1400. The present investigation is focused on the scaling and the reduced power effects on thermal hydraulic similarity after initiation of MSLB events. It is found that the ATLAS facility has the similar thermal hydraulic responses against the MSLB events. However, the initial high secondary pressure before the MSLB initiation resulted in different primary pressure and temperature progression from the APR1400. The break flow from the main steam line is found to be one of the most dominating parameters governing the transient

  17. 现实LOCA分析中不确定性量化分析方法研究%Investigation on Uncertainty Quantification Method in Realistic LOCA Analysis

    Institute of Scientific and Technical Information of China (English)

    林支康; 王婷; 林建树; 梁任; 卢向晖

    2016-01-01

    In this paper,we introduce many kinds of uncertainty quantification methods used in realistic LBLOCA analysis,and quantify the uncertainties of the output of large break loss of coolant accident based on the best estimate thermal hydraulic system code CATHARE GB LBLOCA model of CPR1000 nuclear power plant.Furthermore,we compare and identify the differences in many areas such as the process of input and output parameters and analysis procedure,and recognize that the sensitivity study method is most conservative because of the existing of the artificial conservative assumption,and the normal distribution test is required in the conventional parameter statistic method,Owen factor method and Bootstrap method,but not in Wilks method,and Wilks method can achieve more realistic results.%基于中国改进型三环路压水堆(CPR1000)核电厂最佳估算热工水力系统分析程序(CATHAREGB)大破口失水事故(LBLOCA)分析模型,采用多种不确定性量化分析方法量化LBLOCA分析结果的不确定性,并针对不同方法对输入参数的处理、分析过程和输出结果的处理3个方面进行比较.结果表明,敏感性分析方法由于存在人为的保守性,所以其计算结果最保守,传统的参数统计方法、欧文因子法和Bootstrap方法需进行输出结果的正态性检验,而Wilks方法不需要进行正态性检验且分析结果更加现实.

  18. Simulation on In-Containment Source Term and Virtual Accident Scene of Large-Break LOCA%大破口事故安全壳内气载源项的仿真分析及事故场景虚拟

    Institute of Scientific and Technical Information of China (English)

    肖红光; 朱波; 张帆

    2011-01-01

    The variation of the concentrations of aerosol 131I, airborne 137Cs and 133Xe under 3 different disposal measures, i.e., without spray and emergency ventilation. with spray but without emergency ventilation, and with spray and emergency ventilation, was analyzed after a large-break LOCA for the small-scale experiment reactor. The results showed that the spray played an effective role in reducing the radioactive concentration of 131I and 137Cs, but almost had no effect on the inert gas 133Xe. Under the condition of this study, when the security system failed, the radioactive material would escape once the core melt. Finally, by the virtual simulation of the accident, the variation of the nuclide radioactive concentration in the whole containment was expressed intuitively in real-time and the combination of the accurate simulation data and the visual interface was achieved in this paper.%分析小型实验堆大破口事故后,冷端安全注射时在无喷淋无应急排风、有喷淋无应急排风和有喷淋有应急排风3种处置措施下,气溶胶1311I、气载137Cs和133Xe浓度的变化情况.结果表明,喷淋措施对核素131I和137Cs起到了有效降低放射性浓度的作用,但对惰性气体133Xe几乎没有影响;在本文所研究的工况下,若安全系统功能丧失,一旦堆芯裸露导致堆芯熔化,极有可能出现放射性物质外逸.最后通过对事故的虚拟仿真,将整个安全壳内核素放射性浓度变化状况实时、直观地表现出来,实现了精确仿真数据和可视化界面的有机结合.

  19. Loss of Coolant Accident Analysis Methodology for SMART-P

    Energy Technology Data Exchange (ETDEWEB)

    Bae, K. H.; Lee, G. H.; Yang, S. H.; Yoon, H. Y.; Kim, S. H.; Kim, H. C

    2006-02-15

    The analysis methodology on the Loss-of-coolant accidents (LOCA's) for SMART-P is described in this report. SMART-P is an advanced integral type PWR producing a maximum thermal power of 65.5 MW with metallic fuel. LOCA's are hypothetical accidents that would result from the loss of reactor coolant, at a rate in excess of the capability of the reactor coolant makeup system, from breaks in pipes in the reactor coolant pressure boundary up to and including a break equivalent in size to the double-ended rupture of the largest pipe in the reactor coolant system. Since SMART-P contains the major primary circuit components in a single Reactor Pressure Vessel (RPV), the possibility of a large break LOCA (LBLOCA) is inherently eliminated and only the small break LOCA is postulated. This report describes the outline and acceptance criteria of small break LOCA (SBLOCA) for SMART-P and documents the conservative analytical model and method and the analysis results using the TASS/SMR code. This analysis method is applied in the SBLOCA analysis performed for the ECCS performance evaluation which is described in the section 6.3.3 of the safety analysis report. The prediction results of SBLOCA analysis model of SMART-P for the break flow, system's pressure and temperature distributions, reactor coolant distribution, single and two-phase natural circulation phenomena, and the time of major sequence of events, etc. should be compared and verified with the applicable separate and integral effects test results. Also, it is required to set-up the feasible acceptance criteria applicable to the metallic fueled integral reactor of SMART-P. The analysis methodology for the SBLOCA described in this report will be further developed and validated as the design and licensing status of SMART-P evolves.

  20. Tailings dam-break flow - Analysis of sediment transport

    Science.gov (United States)

    Aleixo, Rui; Altinakar, Mustafa

    2015-04-01

    A common solution to store mining debris is to build tailings dams near the mining site. These dams are usually built with local materials such as mining debris and are more vulnerable than concrete dams (Rico et al. 2008). of The tailings and the pond water generally contain heavy metals and various toxic chemicals used in ore extraction. Thus, the release of tailings due to a dam-break can have severe ecological consequences in the environment. A tailings dam-break has many similarities with a common dam-break flow. It is highly transient and can be severely descructive. However, a significant difference is that the released sediment-water mixture will behave as a non-Newtonian flow. Existing numerical models used to simulate dam-break flows do not represent correctly the non-Newtonian behavior of tailings under a dam-break flow and may lead to unrealistic and incorrect results. The need for experiments to extract both qualitative and quantitative information regarding these flows is therefore real and actual. The present paper explores an existing experimental data base presented in Aleixo et al. (2014a,b) to further characterize the sediment transport under conditions of a severe transient flow and to extract quantitative information regarding sediment flow rate, sediment velocity, sediment-sediment interactions a among others. Different features of the flow are also described and analyzed in detail. The analysis is made by means of imaging techniques such as Particle Image Velocimetry and Particle Tracking Velocimetry that allow extracting not only the velocity field but the Lagrangian description of the sediments as well. An analysis of the results is presented and the limitations of the presented experimental approach are discussed. References Rico, M., Benito, G., Salgueiro, AR, Diez-Herrero, A. and Pereira, H.G. (2008) Reported tailings dam failures: A review of the European incidents in the worldwide context , Journal of Hazardous Materials, 152, 846

  1. Identification of Error of Commissions in the LOCA Using the CESA Method

    Energy Technology Data Exchange (ETDEWEB)

    Tukhbyet-olla, Myeruyert; Kang, Sunkoo; Kim, Jonghyun [KEPCO international nuclear graduate school, Ulsan (Korea, Republic of)

    2015-10-15

    An Errors of commission (EOCs) can be defined as the performance of any inappropriate action that aggravates the situation. The primary focus in current PSA is placed on those sequences of hardware failures and/or EOOs that lead to unsafe system states. Although EOCs can be treated when identified, a systematic and comprehensive treatment of EOC opportunities remains outside the scope of PSAs. However, some past experiences in the nuclear industry show that EOCs have contributed to severe accidents. Some recent and emerging human reliability analysis (HRA) methods suggest approaches to identify and quantify EOCs, such as ATHEANA, MERMOS, GRS, MDTA, and CESA. The CESA method, developed by the Risk and Human Reliability Group at the Paul Scherrer Institute, is to identify potentially risk-significant EOCs, given an existing PSA. The main idea underlying the method is to catalog the key actions that are required in the procedural response to plant events and to identify specific scenarios in which these candidate actions could erroneously appear to be required. This paper aims at identifying EOCs in the LOCA by using the CESA method. This study is focused on the identification of EOCs, while the quantification of EOCs is out of scope. Then, this paper applies the CESA method to the emergency operating procedure (EOP) of LOCA for APR1400. Finally, this study presents potential EOCs that may lead to the aggravation in the mitigation of LOCA. This study has identified the EOC events for APR1400 in the LOCA using CESA method. The result identified three candidate EOCs event using operator action catalog and RAW cutset of LOCA. These candidate EOC events are inappropriate terminations of safety injection system, safety injection tank and containment spray system. Then after reviewing top 100 accident sequences of PSA, this study finally identified one EOC scenario and EOC path, that is, inappropriate termination of safety injection system.

  2. Analysis of Melancholy in Alfred Tennyson’s“Break, Break, Break”

    Institute of Scientific and Technical Information of China (English)

    张兰兰

    2012-01-01

      s: As a“Poet Laureate”, Alfred Lord Tennyson has been loved and respected by critics and readers. He is famous not only for his unsurpassed virtuosity, but also the melancholy feeling in his poetry. He excels at penning short lyrics, among which“Break, Break, Break”is one of the representatives. This paper analyzes the melancholy in the poem from different per⁃spectives, the rhetorical device of repetend, the diction and the sound.

  3. Large-break loss-of-coolant accident phenomena identification and ranking table (PIRT) for the advanced Candu reactor

    Energy Technology Data Exchange (ETDEWEB)

    Popov, N.; Snell, V.G.; Sills, H.E.; Langman, V.J.; Boyack, B. [Atomic Energy of Canada Ltd (Canada)

    2004-07-01

    The Advanced Candu Reactor (ACR) is an evolutionary advancement of the current Candu-6 reactor, aimed at producing electrical power for a capital cost and unit-energy cost significantly less than that of current reactor designs. The ACR retains the modular concept of horizontal fuel channels surrounded by heavy water moderator, as with all Candu reactors. However, ACR uses slightly enriched uranium (SEU) fuel, compared to the natural uranium used in Candu 6. This achieves the twin goals of improved economics (e.g., via reductions in the heavy water requirements and the use of a light water coolant), as well as improved safety. This paper is focused on the double-ended guillotine critical inlet header break (CRIHB) loss-of-coolant accident (LOCA) in an ACR reactor, which is considered as a large break LOCA. Large Break LOCA in water-cooled reactors has been used historically as a design basis event by regulators, and it has attracted a very large share of safety analysis and regulatory review. The LBLOCA event covers a wide range of system behaviours and fundamental phenomena. The Phenomena Identification and Ranking Table (PIRT) for LBLOCA therefore provides a good understanding of many of the safety characteristics of the ACR design. The paper outlines the design characteristics of the ACR reactor that impact the PIRT process and computer code applicability. It also describes the LOCA phenomena, lists all components and systems that have an important role during the event, discusses the PIRT process and results, and presents the final PIRT summary table. (authors)

  4. TRAC-P1: an advanced best estimate computer program for PWR LOCA analysis. I. Methods, models, user information, and programming details

    Energy Technology Data Exchange (ETDEWEB)

    1978-05-01

    The Transient Reactor Analysis Code (TRAC) is being developed at the Los Alamos Scientific Laboratory (LASL) to provide an advanced ''best estimate'' predictive capability for the analysis of postulated accidents in light water reactors (LWRs). TRAC-Pl provides this analysis capability for pressurized water reactors (PWRs) and for a wide variety of thermal-hydraulic experimental facilities. It features a three-dimensional treatment of the pressure vessel and associated internals; two-phase nonequilibrium hydrodynamics models; flow-regime-dependent constitutive equation treatment; reflood tracking capability for both bottom flood and falling film quench fronts; and consistent treatment of entire accident sequences including the generation of consistent initial conditions. The TRAC-Pl User's Manual is composed of two separate volumes. Volume I gives a description of the thermal-hydraulic models and numerical solution methods used in the code. Detailed programming and user information is also provided. Volume II presents the results of the developmental verification calculations.

  5. Analysis of main roof breaking form and its mechanism during first weighting in longwall face

    Institute of Scientific and Technical Information of China (English)

    HUANG Qing-xiang

    2001-01-01

    By field observation and simulating test in shallow seam logwall mining, the asymmetry breaking of main roof is discovered during the first weighting. Based on simulating model test and theoretical analysis, the mechanism of main roof first breaking is revealed, and the asymmetry breaking parameter is determined at all.

  6. Locally Constructed Analogs (LOCA) Daily CMIP5 Climate Projections

    Data.gov (United States)

    US Bureau of Reclamation, Department of the Interior — This archive contains 64 projections of daily LOCA CMIP5 climate over the contiguous United States. This archive includes these meteorological variables at 1/16th...

  7. Locally Constructed Analogs (LOCA) Daily CMIP5 Climate Projections

    Data.gov (United States)

    Federal Geographic Data Committee — This archive contains 64 projections of daily LOCA CMIP5 climate over the contiguous United States. This archive includes these meteorological variables at 1/16th...

  8. Design of a new experimental facility to reproduce LOVA and LOCA consequences on dust resuspension

    Energy Technology Data Exchange (ETDEWEB)

    Malizia, A., E-mail: malizia@ing.uniroma2.it; Gelfusa, M.; Francia, G.; Boccitto, M.; Del Vecchio, M.; Di Giovanni, D.; Richetta, M.; Bellecci, C.; Gaudio, P.

    2015-10-15

    Highlights: • Design and realization of new experimental facility. • Numerical simulation to test the mechanical resistance of the new facility. • New way to experimentally reproduce LOVA and LOCA consequences on dust resuspension inside the tokamaks. - Abstract: Dust resuspension inside the vacuum vessel is one of the key security issues of the new-generation tokamaks (such as ITER or DEMO). It is well known that a fusion device generates dusts due to plasma–surface interactions, which cause a significant erosion of plasma facing components. Consequently, operators will have to manage several hundreds of kilograms of beryllium and tungsten dusts inside the VV. According to the reference categories, two main accidental situations lead to dusts re-suspension: loss of vacuum accidents (LOVA – air flow due to a rupture of a penetration line) and loss of coolant accidents (LOCA – fluid flashing due to a rupture of a coolant system pipe). The authors have gained a strong experience in the field of dust resuspension by virtue of the studies on the STARDUST facility, whose limitations, however, prevent from completing further analysis. These are, in particular, a reduced field of view to track the dust with optical techniques, the impossibility to replicate a LOVA from the upper port as well as any kind of LOCA. To overcome these problems, the authors have designed several new layouts of the facility. Numerical simulations to test the mechanical resistance together with a deep analysis of advantages and limitations have been performed for each layout. The authors will present the proposals for the new facility, the numerical results of the simulations and a comparison between the layouts analyzed. A new experimental facility will be then described to reproduce dust re-suspension due to both LOVA and LOCA consequences.

  9. ANALYSIS OF MEN'S AND WOMEN'S BASKETBALL FAST-BREAKS

    Directory of Open Access Journals (Sweden)

    Ignacio Refoyo

    2009-01-01

    opposition. For men, some dependence relationships were found between the fast break result and the following variables: duration, completion area, and opposition to its completion. For women, the results revealed a weak association between the fast break result and the opposition to its completion.

  10. Cooling the intact loop of primary heat transport system using Shutdown Cooling System in case of LOCA events

    Directory of Open Access Journals (Sweden)

    Icleanu Diana Laura

    2015-01-01

    Full Text Available The purpose of this paper is to model the operation of the Shutdown Cooling System (SDCS for CANDU 6 nuclear power plants in case of LOCA accidents, using Flowmaster calculation code, by delimiting models and setting calculation assumptions, input data for hydraulic analysis and input data for calculating thermal performance check for heat exchangers that are part of this system.

  11. LOCA下喷放水流对周围仪表仪器的影响分析%Analysis of Effect of Flashing Liquid Jet on Surrounding Instruments during LOCA

    Institute of Scientific and Technical Information of China (English)

    顾培文; 陶俊; 曹学武; 佟立丽

    2011-01-01

    在核电厂一回路发生冷却剂流失事故(LOCA)时,冷却剂从破口喷出,急速汽化,可对周嗣的仪表仪器造成强冲击力的破坏,产生极为严重的后果.本文以900MW压水堆为研究对象,使用数值模拟的方法,建立一维喷放模型,分析LOCA可能造成的破坏力.分析结果表明,以激波作为分界线,在激波形成前的仪表仪器将受到强冲击力,而在激波形成后冲击力对仪表仪器的影响可以忽略.%When the loss of coolant accident(LOCA) happens in the nuclear power plants, the coolant will be discharged to the low-pressure environment and evaporated immediately, causing damage to the surrounding instruments. The numerical software has been used to establish one-dimensional model for the prediction of possible damage in this severe accident, thus giving some advice for the nuclear power plant layout. The analytical result shows that the shock wave should be seen as a critical line, within which the instrument will be under high pressure, beyond which almost no mechanical damage will be caused.

  12. Statistical analysis of the breaking processes of Ni nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Mochales, P [Departamento de Fisica de la Materia Condensada, Facultad de Ciencias, Universidad Autonoma de Madrid, c/ Francisco Tomas y Valiente 7, Campus de Cantoblanco, E-28049-Madrid (Spain); Paredes, R [Centro de Fisica, Instituto Venezolano de Investigaciones CientIficas, Apartado 20632, Caracas 1020A (Venezuela); Pelaez, S; Serena, P A [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones CientIficas, c/ Sor Juana Ines de la Cruz 3, Campus de Cantoblanco, E-28049-Madrid (Spain)], E-mail: pedro.garciamochales@uam.es

    2008-06-04

    We have performed a massive statistical analysis on the breaking behaviour of Ni nanowires using molecular dynamic simulations. Three stretching directions, five initial nanowire sizes and two temperatures have been studied. We have constructed minimum cross-section histograms and analysed for the first time the role played by monomers and dimers. The shape of such histograms and the absolute number of monomers and dimers strongly depend on the stretching direction and the initial size of the nanowire. In particular, the statistical behaviour of the breakage final stages of narrow nanowires strongly differs from the behaviour obtained for large nanowires. We have analysed the structure around monomers and dimers. Their most probable local configurations differ from those usually appearing in static electron transport calculations. Their non-local environments show disordered regions along the nanowire if the stretching direction is [100] or [110]. Additionally, we have found that, at room temperature, [100] and [110] stretching directions favour the appearance of non-crystalline staggered pentagonal structures. These pentagonal Ni nanowires are reported in this work for the first time. This set of results suggests that experimental Ni conducting histograms could show a strong dependence on the orientation and temperature.

  13. Scram discharge volume break studies accident sequence analysis

    Energy Technology Data Exchange (ETDEWEB)

    Harrington, R.M.; Hodge, S.A.

    1982-01-01

    This paper is a summary of a report describing the predicted response of Unit 1 at the Tennessee Valley Authority (TVA) Browns Ferry Nuclear Plant to a hypothetical small break loss of coolant accident (SBLOCA) outside of containment. The accident studied would be initiated by a break in the scram discharge volume (SDV) piping when it is pressurized to full reactor vessel pressure as a normal consequence of a reactor scram. If the scram could be reset, the scram outlet valves would close to isolate the SDV and the piping break from the reactor vessel. However, reset is possible only if the conditions that caused the scram have cleared; it has been assumed in this study that the scram signal remains in effect over a long period of time.

  14. Fuel Behaviour at High During RIA and LOCA Accidents; Comportamiento del Combustible de Alto Quemado en Accidents RIA y LOCA

    Energy Technology Data Exchange (ETDEWEB)

    Barrio del Juanes, M.T.; Garcia Cuesta, J.C.; Vallejo Diaz, I.; Herranz Puebla

    2001-07-01

    Safety analysis of high burnup fuel requires ensuring the acceptable performance under design basis accidents, in particular during conditions representative of Reactivity Accidents (RIA) and Loss-of-Coolant Accidents (LOCA). The report's objective is to compile the state of the art on these issues. This is mainly focused in the effort made to define the applicability of safety criteria to the high burnup fuel. Irradiation damage modifies fuel rod properties, thus the probability of fuel to withstand thermal and mechanical loads during an accident could be quite different compared with unirradiated fuel. From the thermal point of view, fuel conductivity is the most affected property, decreasing notably with irradiation. From the mechanical point of view, a change in the pellet microstructure at its periphery is observed at high burnup (remiffect). Cladding is also effected during operation, showing a significant external and internal corrosion. All these phenomena result in the decrease of efficiency in heat transfer an in the reduction of capability to accommodate mechanical loads; this situation is especially significant at high burnup, when pellet-cladding mechanical interaction is present. Knowledge about these phenomena is not possible without appropriate experimental programmes. The most relevant have been performed in France, Japan, United States and Russia. Results obtained with fuel at high burnup show significant differences with respect to the phenomena observed in fuel at the present discharge burnup. Indeed, this is the encouragement to research about this occurrence. This study is framed within the CSN-CIEMAT agreement, about Fuel Thermo-Mechanical Behaviour at High Burnup. (Author) 172 refs.

  15. Assessment of RELAP/MOD3 using BETHSY 6.2TC 6-inch cold leg side break comparative test

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Young-Jong; Jeong, Jae-Jun; Chang, Won-Pyo; Kim, Dong-Su [Korea Atomic Energy Research Institute, Yusung, Taejon (Korea, Republic of)] [and others

    1996-10-01

    This report presents the results of the RELAP5/MOD3 Version 7j assessment on BETHSY 6.2TC. BETHSY 6.2TC test corresponding to a six inch cold leg break LOCA of the Pressurizer Water Reactor(PWR). The primary objective of the test was to provide reference data of two facilities of different scales (BETHSY and LSTF facility). On the other hand, the present calculation aims at analysis of RELAP5/N4OD3 capability on the small break LOCA simulation, The results of calculation have shown that the RELAP5/MOD3 reasonably predicts occurrences as well as trends of the major phenomena such as primary pressure, timing of loop seal clearing, liquid hold up, etc. However, some disagreements also have been found in the predictions of loop seal clearing, collapsed core water level after loop seal clearing, and accumulator injection behaviors. For better understanding of discrepancies in same predictions, several sensitivity calculations have been performed as well. These include the changes of two-phase discharge coefficient at the break junction and some corrections of the interphase drag term. As result, change of a single parameter has not improved the overall predictions and it has been found that the interphase drag model has still large uncertainties.

  16. Recirculation pump discharge line break tests at ROSA-III for a boiling water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, M.; Anoda, Y.; Kumamaru, H.; Nakamura, H.; Shiba, M.; Tasaka, K.

    1985-08-01

    Three loss-of-coolant accident (LOCA) tests were conducted at the Rig of Safety Assessment (ROSA)-III test facility, which simulates boiling water reactor (BWR)/6-251 with a volumetric scaling factor of 1/424. The fundamental features of the recirculation pump discharge line break LOCA and the effects of break areas on the features are investigated. It has been confirmed experimentally that the LOCA phenomena in the discharge line break are analogous to those in the suction line break with the same effective choking flow area, which is a sum of the least choking flow areas along the break flow paths and controls the system pressure responses. In general, the maximum effective choking flow area is (A /SUB j/ + A /SUB p/ ) for discharge line breaks and (A /SUB j/ + A /SUB o/ ) for suction line breaks, where A /SUB j/ , A /SUB p/ , and A /SUB o/ are the flow areas of the jet pump drive nozzles, the main recirculation pump discharge nozzle, and the break, respectively. The similarity between the ROSA-III test and a BWR LOCA has been confirmed in the key phenomena by the analyses using the RELAP5/MOD1 code. An atypical behavior is observed in the fuel rod surface temperature transient in the early phase of blowdown due to the limitation of the ROSA-III initial core power.

  17. R&D Plan for RISMC Industry Application #1: ECCS/LOCA Cladding Acceptance Criteria

    Energy Technology Data Exchange (ETDEWEB)

    Szilard, Ronaldo Henriques [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zhang, Hongbin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Epiney, Aaron Simon [Idaho National Lab. (INL), Idaho Falls, ID (United States); Tu, Lei [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-04-01

    The Nuclear Regulatory Commission (NRC) is finalizing a rulemaking change that would revise the requirements in 10 CFR 50.46. In the proposed new rulemaking, designated as 10 CFR 50.46c, the NRC proposes a fuel performance-based equivalent cladding reacted (ECR) criterion as a function of cladding hydrogen content before the accident (pre-transient) in order to include the effects of higher burnup on cladding performance as well as to address other technical issues. A loss of operational margin may result due to the more restrictive cladding embrittlement criteria. Initial and future compliance with the rule may significantly increase vendor workload and licensee costs as a spectrum of fuel rod initial burnup states may need to be analyzed to demonstrate compliance. The Idaho National Laboratory (INL) has initiated a project, as part of the DOE Light Water Reactor Sustainability Program (LWRS), to develop analytical capabilities to support the industry in the transition to the new rule. This project is called the Industry Application 1 (IA1) within the Risk-Informed Safety Margin Characterization (RISMC) Pathway of LWRS. The general idea behind the initiative is the development of an Integrated Evaluation Model (IEM). The motivation is to develop a multiphysics framework to analyze how uncertainties are propagated across the stream of physical disciplines and data involved, as well as how risks are evaluated in a LOCA safety analysis as regulated under 10 CFR 50.46c. This IEM is called LOTUS which stands for LOCA Toolkit for US, and it represents the LWRS Program’s response to the proposed new rule making. The focus of this report is to complete an R&D plan to describe the demonstration of the LOCA/ECCS RISMC Industry Application # 1 using the advanced RISMC Toolkit and methodologies. This report includes the description and development plan for a RISMC LOCA tool that fully couples advanced MOOSE tools already in development in order to characterize and optimize

  18. Prediction of Leak Flow Rate Using FNNs in Severe LOCA Circumstances

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Yeong; Yoo, Kwae Hwan; Kim, Ju Hyun; Na, Man Gyun [Chosun University, Gwangju (Korea, Republic of); Hur, Seop; Kim, Chang Hwoi [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    Leak flow rate is a function of break size, differential pressure ( i.e., difference between internal and external reactor vessel pressure), temperature, and so on. Specially, the leak flow rate is strongly dependent on the break size and the differential pressure, but the break size is not measured and the integrity of pressure sensors is not assured in severe circumstances. In this study, a fuzzy neural network (FNN) model is proposed to predict the leak flow rate out of break, which has a direct impact on the important times (time approaching the core exit temperature that exceeds 1200 .deg. F, core uncover time, reactor vessel failure time, etc.). Since FNN is a data-based model, it requires data to develop and verify itself. However, because actual severe accident data do not exist to the best of our knowledge, it is essential to obtain the data required in the proposed model using numerical simulations. These data were obtained by simulating severe accident scenarios for the optimized power reactor 1000 (OPR 1000) using MAAP4 code. In this study, FNN model was developed to predict the leak flow rate in severe post-LOCA circumstances.. The training data were selected from among all the acquired data using an SC method to train the proposed FNN model with more informative data. The developed FNN model predicted the leak flow rate using the time elapsed after reactor shutdown and the predicted break size, and its validity was verified in the basis of the simulation data of OPR1000 using MAAP4 code.

  19. Transient deformation properties of Zircaloy for LOCA simulation. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hann, C. R.; Mohr, C. L.; Busness, K. M.; Olson, N. J.; Reich, F. R.; Stewart, K. B.

    1980-05-01

    This experimental data report is Volume 4 of a series of 5 volumes describing the oxidation and deformation rate behavior of Zircaloy cladding under simulated LOCA conditions. It contains listings of strain versus stress, time, and temperature evaluated from the numerical constitutive relationships and the original data used to develop them. This volume also contains listings of the ramp load, pressure, and temperature test data from both current and previous phases of the series, as well as material describing applications of the data.

  20. An analysis of gamma-ray burst spectral break models

    CERN Document Server

    Zhang, B; Zhang, Bing; Meszaros, Peter

    2002-01-01

    Typical gamma-ray burst spectra are characterized by a spectral break, Ep, which for bright BATSE bursts is found to be narrowly clustered around 300 keV. Recently identified X-ray flashes, which may account for a significant portion of the whole GRB population, seem to extend the Ep distribution to a broader range below 40 keV. On the other hand, within the cosmological fireball model, the issues concerning the dominant energy ingredient of the fireball as well as the location of the GRB emission site are not unambiguously settled, leading to several variants of the fireball model. Here we analyze these models within a unified framework, and critically reexamine the Ep predictions in the various model variants, focusing on their predicted properties. Attention is focused on the ability of the models to match a narrowness of the Ep distribution, and the correlations among Ep and some other measurable observables, as well as the effect of extending these properties to X-ray flash sources. These model propertie...

  1. Analysis on a Nambu--Jona-Lasinio Model of Dynamical Supersymmetry Breaking

    CERN Document Server

    Cheng, Yifan; Faisel, Gaber; Kong, Otto C W

    2016-01-01

    This is a report on our newly proposed model of dynamical supersymmetry breaking with some details of the analysis involved. The model in the simplest version has only a chiral superfield (multiplet), with a strong four-superfield interaction in the K\\"ahler potential that induces a real two-superfield composite with vacuum condensate. The latter has supersymmetry breaking parts, which we show to bear nontrivial solution following basically a standard nonperturbative analysis for a Nambu--Jona-Lasinio type model on a superfield setting. The real composite superfield has a spin one component but is otherwise quite unconventional. We discuss also the parallel analysis for the effective theory with the composite. Plausible vacuum solutions are illustrated and analyzed. The supersymmetry breaking solutions have generated soft mass(es) for the scalar avoiding the vanishing supertrace condition for the squared-masses of the superfield components. We also present some analysis of the resulted low energy effective th...

  2. French investigations of high burnup effect on LOCA thermomechanical behavior: Part 1. Experimental programmes in support of LOCA design methodologies

    Energy Technology Data Exchange (ETDEWEB)

    Waeckel, N. [EDF/SEPTEN Villeurbanne (France); GrandJean, C. [IPSN, Cadarache (France); Cauvin, R.; Lebuffe, C. [EDF/SCMI, Chinon (France)

    1997-01-01

    Within the framework of Burn-Up extension request, EDF, FRAMATOME, CEA and IPSN have carried out experimental programmes in order to provide the design of fuel rods under LOCA conditions with relevant data. The design methods used in France for LOCA are based on standard Appendix K methodology updated to take into account some penalties related to the actual conditions of the Nuclear Power Plant. Best-Estimate assessments are used as well. Experimental programmes concern plastic deformation and burst behavior of advanced claddings (EDGAR) and thermal shock quenching behavior of highly irradiated claddings (TAGCIR). The former reveals the important role played by the {alpha}/{beta} transformation kinetics related to advanced alloys (Niobium alloys) and the latter the significative impact of hydrogen charged during in-reactor corrosion on oxidation kinetics and failure behavior in terms of cooling rates.

  3. French investigations of high burnup effect on LOCA thermomecanical behavior. Part two. Oxidation and quenching experiments under simulated LOCA conditions with high burnup clad material

    Energy Technology Data Exchange (ETDEWEB)

    GrandJean, C. [IPSN, Cadarache (France); Cauvin, R.; Lebuffe, C. [EDF/SCMI, Chinon (France)] [and others

    1997-01-01

    In the frame of the high burnup fuel studies to support a possible extension of the current discharge burnup limit, experimental programs have been undertaken, jointly by EDF and IPSN in order to study the thermal-shock behavior of high burnup fuel claddings under typical LOCA conditions. The TAGUS program used unirradiated cladding samples, bare or bearing a pre-corrosion state simulating the end-of-life state of high burnup fuel claddings: the TAGCIR program used actually irradiated cladding samples taken from high burnup rods irradiated over 5 cycles in a commercial EDF PWR and having reached a rod burnup close to 60 GWd/tU. The thermal-shock failure tests consisted in oxidizing the cladding samples under steam flow, on both inner and outer faces or on the outer face alone, and subjecting them to a final water quench. The heating was provided by an inductive furnace the power of which being regulated through monitoring of the sample surface temperature with use of a single-wave optical pyrometer. Analysis of the irradiated tests (TAGCIR series) evidenced an increased oxidation rate as compared to similar tests on unirradiated samples. Results of the quenching tests series on unirradiated and irradiated samples are plotted under the usual presentation of failure maps relative to the oxidation parameters ECR (equivalent cladding reacted) or e{sub {beta}} (thickness of the remaining beta phase layer) as a function of the oxidation temperature. Comparison of the failure limits for irradiated specimens to those for unirradiated specimens indicates a lower brittleness under two side oxidation and possibly the opposite under one-side oxidation. The tentative analysis of the oxidation and quenching tests results on irradiated samples reveals the important role played by the hydrogen charged during in-reactor corrosion on the oxidation kinetics and the failure bearing capability of the cladding under LOCA transient conditions.

  4. An analysis of oil production by OPEC countries: Persistence, breaks, and outliers

    Energy Technology Data Exchange (ETDEWEB)

    Pestana Barros, Carlos, E-mail: cbarros@iseg.utl.p [Instituto Superior de Economia e Gestao and Research Unit on Complexity and Economics, Technical University of Lisbon, Lisbon (Portugal); Gil-Alana, Luis A., E-mail: alana@unav.e [University of Navarra, Pamplona (Spain); Payne, James E., E-mail: jepayne@ilstu.ed [Department of Economics, Illinois State University, Normal, IL 61790-4200 (United States)

    2011-01-15

    This study examines the time series behaviour of oil production for OPEC member countries within a fractional integration modelling framework recognizing the potential for structural breaks and outliers. The analysis is undertaken using monthly data from January 1973 to October 2008 for 13 OPEC member countries. The results indicate there is mean reverting persistence in oil production with breaks identified in 10 out of the 13 countries examined. Thus, shocks affecting the structure of OPEC oil production will have persistent effects in the long run for all countries, and in some cases the effects are expected to be permanent. - Research Highlights: {yields}Mean reverting persistence in oil production with breaks identified in 10 out of the 13 countries examined. {yields} Standard analysis based on cointegration techniques and involving oil production should be examined in the more general context of fractional cointegraton. {yields} Analysis of outliers did not alter the main conclusions of the study.

  5. System-level validation of CATHENA MOD-3.5D for early blowdown phase of large LOCA - RD-14M tests B0405-B0413

    Energy Technology Data Exchange (ETDEWEB)

    Gu, J.W.; McGee, G.R. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)], E-mail: guj@aecl.ca

    2008-07-01

    To investigate the integrated effect of multiple phenomena on CATHENA MOD-3.5d code uncertainty, for the early blowdown phase of large loss of coolant accident (LOCA), one RD-14M test series (B0405-B0413) is used to perform a system-level validation. The peak sheath temperature in the Fuel-Element-Simulator (FES) is selected as the key output parameter used to quantify the code bias and uncertainty in the validation. In the nine tests, the test conditions (break size, pump and power trip time, fluid sub-cooling and pressurizer isolation) are systematically varied and simulated, so that their effects on the magnitude and timing of the peak FES-sheath temperatures are demonstrated. The base test, B0405 is selected to perform sensitivity and uncertainty analyses. The sensitivity analyses show that the choice of film-boiling heat-transfer correlation has a significant effect on the prediction of the FES-sheath temperatures during the FES quenching period. Uncertainty analysis demonstrates a mean bias of about +20{sup o}C, with a range of about {+-}30{sup o}C to the upper and lower bounds. These results compare very well with the estimated code accuracy based on all nine tests of B0405-B0413. (author)

  6. Break and trend analysis of EUMETSAT Climate Data Records

    Science.gov (United States)

    Doutriaux-Boucher, Marie; Zeder, Joel; Lattanzio, Alessio; Khlystova, Iryna; Graw, Kathrin

    2016-04-01

    EUMETSAT reprocessed imagery acquired by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on board Meteosat 8-9. The data covers the period from 2004 to 2012. Climate Data Records (CDRs) of atmospheric parameters such as Atmospheric Motion Vectors (AMV) as well as Clear and All Sky Radiances (CSR and ASR) have been generated. Such CDRs are mainly ingested by ECMWF to produce a reanalysis data. In addition, EUMETSAT produced a long CDR (1982-2004) of land surface albedo exploiting imagery acquired by the Meteosat Visible and Infrared Imager (MVIRI) on board Meteosat 2-7. Such CDR is key information in climate analysis and climate models. Extensive validation has been performed for the surface albedo record and a first validation of the winds and clear sky radiances have been done. All validation results demonstrated that the time series of all parameter appear homogeneous at first sight. Statistical science offers a variety of analyses methods that have been applied to further analyse the homogeneity of the CDRs. Many breakpoint analysis techniques depend on the comparison of two time series which incorporates the issue that both may have breakpoints. This paper will present a quantitative and statistical analysis of eventual breakpoints found in the MVIRI and SEVIRI CDRs that includes attribution of breakpoints to changes of instruments and other events in the data series compared. The value of different methods applied will be discussed with suggestions how to further develop this type of analysis for quality evaluation of CDRs.

  7. Energy analysis and break-even distance for transportation for biofuels in comparison to fossil fuels

    Science.gov (United States)

    In the present analysis various forms fuel from biomass and fossil sources, their mass and energy densities, and their break-even transportation distances to transport them effectively were analyzed. This study gives an insight on how many times more energy spent on transporting the fuels to differe...

  8. An analysis of oil production by OPEC countries. Persistence, breaks, and outliers

    Energy Technology Data Exchange (ETDEWEB)

    Barros, Carlos Pestana [Instituto Superior de Economia e Gestao and Research Unit on Complexity and Economics, Technical University of Lisbon, Lisbon (Portugal); Gil-Alana, Luis A. [University of Navarra, Pamplona (Spain); Payne, James E. [Department of Economics, Illinois State University, Normal, IL 61790-4200 (United States)

    2011-01-15

    This study examines the time series behaviour of oil production for OPEC member countries within a fractional integration modelling framework recognizing the potential for structural breaks and outliers. The analysis is undertaken using monthly data from January 1973 to October 2008 for 13 OPEC member countries. The results indicate there is mean reverting persistence in oil production with breaks identified in 10 out of the 13 countries examined. Thus, shocks affecting the structure of OPEC oil production will have persistent effects in the long run for all countries, and in some cases the effects are expected to be permanent. (author)

  9. MELCOR Analyses of Divertor Ex-vessel LOCA During Normal Operation. Contract EFDA 01/599, Deliverable 3 - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    ChunHong Sheng

    2002-06-01

    A MELCOR model of ITER-FEAT divertor cooling system has been developed for the analyses of thermal-hydraulic accidents as specified in the Accident Analysis Specifications (AAS-3) for the ITER-FEAT Generic Site Safety Report (GSSR). The model is based on data from the Safety Analysis Data List (SADL-3). The report presents the results of DV ex-vessel LOCA with plasma shutdown from MELCOR calculations. The intention is to verify previous analyses with ATHENA and INTRA to update parts of GSSR documenting the analysis of representative accident sequences for ITER.

  10. Break-Even Income Analysis of Pharmacy Graduates Compared to High School and College Graduates.

    Science.gov (United States)

    Chisholm-Burns, Marie A; Gatwood, Justin; Spivey, Christina A; Dickey, Susan E

    2016-04-25

    Objective. To project the net cumulative income break-even point between practicing pharmacists and those who enter the workforce directly after high school graduation or after obtaining a bachelor's degree. Methods. Markov modeling and break-even analysis were conducted. Estimated costs of education were used in calculating net early career earnings of high school graduates, bachelor's degree holders, pharmacists without residency training, and pharmacists with residency training. Results. Models indicate that over the first 10 years of a pharmacist's career, they accumulate net earnings of $716 345 to $1 064 840, depending on cost of obtaining the PharmD degree and career path followed. In the break-even analysis, all pharmacy career tracks surpassed net cumulative earnings of high school graduates by age 33 and bachelor's degree holders by age 34. Conclusion. Regardless of the chosen pharmacy career track and the typical cost of obtaining a PharmD degree, the model under study assumptions demonstrates that pharmacy education has a positive financial return on investment, with a projected break-even point of less than 10 years upon career entry.

  11. Two-phase flow across a partially damaged core during the reflood phase of a loca

    Energy Technology Data Exchange (ETDEWEB)

    Ruyer, P., E-mail: pierre.ruyer@irsn.fr [IRSN PSN/SEMIA/LIMAR, B.P. 3, 13 115 St-Paul-Lez-Durance Cedex (France); Seiler, N.; Biton, B.; Lelong, F.; Secondi, F.; Baalbaki, D. [IRSN PSN/SEMIA/LIMAR, B.P. 3, 13 115 St-Paul-Lez-Durance Cedex (France); Gradeck, M. [LEMTA Nancy University CNRS Vandoeuvre les Nancy (France)

    2013-11-15

    This study focuses on thermal-hydraulic simulations, at sub-channel scale, of a damaged PWR reactor core during a Loss Of Coolant Accident (LOCA). The aim of this study is to simulate the thermal-hydraulics to provide the thermal-mechanical code DRACCAR with an accurate wall heat transfer law. This latter code is developed by the Institut de Radioprotection et de Sûreté Nucléaire (IRSN) to evaluate the thermics and deformations of fuel assemblies within the core. The present paper first describes the use of CFD to perform analysis at sub-channel scale. Then we study the capabilities of existing codes CATHARE-3 and CESAR to simulate dispersed droplet flows.

  12. Thermal-Hydraulic Integral Effect Test with ATLAS for an Intermediate Break Loss of Coolant Accident at a Pressurizer Surge Line

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Kyoung Ho; Seok Cho; Park, Hyun Sik; Choi, Nam Hyun; Park, Yu Sun; Kim, Jong Rok; Bae, Byoung Uhn; Kim, Yeon Sik; Kim, Kyung Doo; Choi, Ki Yong; Song, Chul Hwa [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    The main objectives of this test were not only to provide physical insight into the system response of the APR1400 during the pressurizer surge line break accident but also to produce an integral effect test data to validate the SPACE code. In order to simulate a double-ended guillotine break of a pressurizer surge line in the APR1400, the IB-SUR-01R test was performed with ATLAS. The major thermal-hydraulic phenomena such as the system pressures, the collapsed water levels, and the break flow rate were presented and discussed. Despite the core was uncovered, no excursion in the cladding temperature was observed. The pressurizer surge line break can be classified as a hot leg break from a break location point of view. Compared with a cold leg break, coolability in the core may be better in case of a hot leg break due to the enhanced flow in the core region. This integral effect test data will be used to evaluate the prediction capability of existing safety analysis codes of the MARS and the RELAP5 as well as the SPACE code. Furthermore, this data can be utilized to identify any code deficiency for an IBLOCA simulation, especially for DVI-adapted plants. Redefinition of break size for design basis accident (DBA) based on risk information is being extensively investigated due to the potential for safety benefits and unnecessary burden reduction from current LBLOCA (large break loss of coolant accident)-based ECC (Emergency Core Cooling) Acceptance Criteria. As a transition break size (TBS), the rupture of medium-size pipe is considered to be more important than ever in risk-informed regulation (RIR)-relevant safety analysis. As plants age, are up-rated, and continue to seek improved operating efficiencies, the small break and intermediate break LOCA (IBLOCA) can become a concern. In particular, IBLOCA with DVI (Direct Vessel Injection) features will be addressed to support redefinition of a design-basis LOCA. With an aim of expanding code validation to address small

  13. Characterization of the relocated and dispersed fuel in the Halden reactor project LOCA tests based on gamma scan data

    Energy Technology Data Exchange (ETDEWEB)

    Brankov, Vladimir, E-mail: vladimir.brankov@psi.ch [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland); Khvostov, Grigori; Mikityuk, Konstantin [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Pautz, Andreas [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland); Wiesenack, Wolfgang [Institutt For Energiteknikk OECD Halden Reactor Project, P.O. Box 173, Halden 1751 (Norway)

    2016-04-15

    Highlights: • We propose method to estimate dispersed fuel based on gamma scan data. • Analysis to determine the origin of relocated and dispersed fuel in Halden LOCA tests. • Useful data is gathered for code validation. • Suggestions are discussed to improve the quality of gamma scan data at Halden. • Dispersed and relocated material is a mixture of fuel from pellet periphery and bulk. - Abstract: The on-going Loss-of-Coolant Accident (LOCA) test program at the OECD Halden Reactor Project (HRP) conducts in-house gamma scanning as standard post-irradiation examination (PIE) procedure on Light Water Reactor (LWR) fuel rods. One of the primary objectives of the program is to investigate fuel relocation into the balloon region and fuel dispersal through the cladding rupture opening after burst. A simple model called Gamma Transport Model was formulated for the purpose of interpretation of fuel relocation based on the gamma scan data. Fuel relocation may have a strong effect on the linear heat generation rate at the balloon due to, firstly, increase in linear fuel density, and secondly due to differences in burn-up and local heat generation rate at the periphery and bulk of the pellet. For this analysis, a pair of short-lived isotopes with very different fission product yields for {sup 235}U and {sup 239}Pu is selected from the gamma scan spectrum. The intention is to use the difference in the ratio of their concentrations in the balloon region to qualitatively make conclusion on the fuel relocation. As a separate outcome, the same analysis can be applied to the dispersed fuel region and to draw conclusion on its origin (pellet rim or bulk). The Gamma Transport Model is validated against a special (non-destructive) case from the Halden LOCA test program and then applied for the analysis of selected tests. In addition, a methodology is presented for estimation of the amount of dispersed fuel from the LOCA tests based on the gamma scan data. Currently, at

  14. Analysis of Steam Line Break for the Development of KNGR EOG

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, H.Y.; Lee, S.R. [Korea Electric Power Research Institute, Taejon (Korea)

    2000-02-01

    The steam line break accidents are analyzed for the development of KNGR emergency operation guidelines (EOG). Realistic plant initial conditions and assumptions are applied because it is important to evaluate the best-estimate plant behavior for the development of EOG. The steam line break analysis is required to prepare the Excess Steam Demand Event (ESDE) of the Optimal Recovery Guidelines (ORG). Five cases of SLBFP, SLBFPLOP, SLBZP, SLPFPNSI, and ZP2RCP are analysed considering the power level, plant conditions, and possible operator actions. The results show that the accident can be mitigated safely and the requirements described in the guidelines are satisfied when the plant is controlled following the provided procedures . (author). 3 refs., 70 figs.

  15. Carbon Break Even Analysis: Environmental Impact of Tablets in Higher Education

    Directory of Open Access Journals (Sweden)

    Fadi Safieddine

    2016-05-01

    Full Text Available With the growing pace of tablets use and the large focus it is attracting especially in higher education, this paper looks at an important aspect of tablets; their carbon footprint. Studies have suggested that tablets have positive impact on the environment; especially since tablets use less energy than laptops or desktops. Recent manufacturers’ reports on the carbon footprint of tablets have revealed that a significant portion, as much as 80%, of the carbon footprint of tablets comes from production and delivery as opposed to the operational life-cycle of these devices. Thus rending some of previous assumptions about the environmental impact of tablets questionable. This study sets to answer a key question: What is the break-even analysis point when saving on printed paper offsets the carbon footprint of producing and running the tablet in higher education. A review of the literature indicated several examples of tablet models and their carbon emission impact; this is compared to the environmental savings on paper that green courses could produce. The analysis of the carbon break-even point shows that even when considering some of the most efficient and least carbon impact tablets available on the market with a carbon-footprint production of 153Kg CO2e, the break-even point is 81.5 months; referring to 6 years, 9 months and 15 days of use. This exceeds the life-cycle of an average tablet of five years and average degree duration of four years. While tablets still have the least carbon-footprint impact compared to laptops and desktops, to achieve the break-even point of carbon neutral operations this study concludes that manufacturers need to find more environmentally efficient ways of production that would reduce the carbon-footprint product to a level that does not exceed 112.8kg CO2e.

  16. The Breaking Bad Constellation. Analysis of the Newly Found Complementarity between Television and Internet

    Directory of Open Access Journals (Sweden)

    Sarah SEPULCHRE

    2011-01-01

    Full Text Available The hypothesis developed in this paper is that television and Internet are complementary. Both media collaborate in order to propose genuine transmedia narratives. These news adaptations are not identical to movie or novel adaptations, notably because they are simultaneous, interactive and multi-genres. The analysis of Breaking Bad will be presented in the second part of this communication. In the first one, concepts of “remediation” and “convergence”, which constitute the framework of our demonstration, are clarified.

  17. A probabilistic method for leak-before-break analysis of CANDU reactor pressure tubes

    Energy Technology Data Exchange (ETDEWEB)

    Puls, M.P.; Wilkins, B.J.S.; Rigby, G.L. [Whiteshell Labs., Pinawa (Canada)] [and others

    1997-04-01

    A probabilistic code for the prediction of the cumulative probability of pressure tube ruptures in CANDU type reactors is described. Ruptures are assumed to result from the axial growth by delayed hydride cracking. The BLOOM code models the major phenomena that affect crack length and critical crack length during the reactor sequence of events following the first indications of leakage. BLOOM can be used to develop unit-specific estimates of the actual probability of pressure rupture in operating CANDU reactors and supplement the existing leak before break analysis.

  18. Divorced People: Analysis of the Characteristics of the Break-up Process

    Directory of Open Access Journals (Sweden)

    Ana Muñoz-Eguileta

    2009-08-01

    Full Text Available The goal of this study was to carry out an analysis of the characteristics of the break-up process in a sample of divorced people including variables such as length of marriage, use of mediation services and time elapsed since divorce. Anumber of mediation centres and associations of divorced people participated in the project. The results showed that a closer contact with the ex–spouse was related to a shorter duration of marital conflict and with the use of the mediation services. These findings are discussed along with other results.

  19. A Procedure to Address the Fuel Rod Failures during LB-LOCA Transient in Atucha-2 NPP

    Directory of Open Access Journals (Sweden)

    Martina Adorni

    2011-01-01

    Full Text Available Depending on the specific event scenario and on the purpose of the analysis, the availability of calculation methods that are not implemented in the standard system thermal hydraulic codes might be required. This may imply the use of a dedicated fuel rod thermomechanical computer code. This paper provides an outline of the methodology for the analysis of the 2A LB-LOCA accident in Atucha-2 NPP and describes the procedure adopted for the use of the fuel rod thermomechanical code. The methodology implies the application of best estimate thermalhydraulics, neutron physics, and fuel pin performance computer codes, with the objective to verify the compliance with the specific acceptance criteria. The fuel pin performance code is applied with the main objective to evaluate the extent of cladding failures during the transient. The procedure consists of a deterministic calculation by the fuel performance code of each individual fuel rod during its lifetime and in the subsequent LB-LOCA transient calculations. The boundary and initial conditions are provided by core physics and three-dimensional neutron kinetic coupled thermal-hydraulic system codes calculations. The procedure is completed by the sensitivity calculations and the application of the probabilistic method, which are outside the scope of the current paper.

  20. Analysis of a gas stratification break-up by a vertical jet using the GOTHIC code

    Energy Technology Data Exchange (ETDEWEB)

    Fernández-Cosials, Mikel Kevin; Jimenez, Gonzalo, E-mail: gonzalo.jimenez@upm.es; Lopez-Alonso, Emma

    2016-02-15

    Highlights: • Study of a light gas distribution with the GOTHIC code based on the OECD/NEA IBE-3. • Sensitivity analysis on turbulence model, discretization scheme and heat transfer. • The jet erosion phenomena is captured properly with a relatively coarse mesh. • Development of a tool to evaluate the influence of each parameter on the simulation. • Several recommendation on modeling a stratification break-up are included. - Abstract: During a severe accident in light water reactor (LWR), hydrogen concentration can overpass the flammability limits locally, so the correct simulation of its behavior during a release is critical. The capability assessment of computational fluid dynamics tools to calculate the hydrogen distribution under different conditions has been the focus of intense research worldwide. In this context, the OECD/NEA conducted an international benchmark exercise (IBE-3), which was focused on the break-up of a stratified layer of a light gas by a vertical jet. The participants performed their simulations before the experiment data was released. When the data was released, it was noticed that a combination of several parameters like the mesh, turbulence model or solver controls were responsible for the broad differences between the participants’ results. To obtain information about how each parameter affects the simulation, a post-test sensitivity analysis has been done by the UPM. In this paper, the IBE-3 experiment simulation with GOTHIC 8.0 is presented along with extensive sensitivity analyses of the relevant parameters. The first objective of the work is to test the capability of GOTHIC 8.0 to simulate properly a gas stratification break-up by a vertical jet with a relatively coarse mesh. The second objective of the paper is to relate each sensitivity parameter with each other and with the experiment through the Parameter Influence Chart, a helpful tool specially designed for this purpose.

  1. Consistency of Trend Break Point Estimator with Underspecified Break Number

    Directory of Open Access Journals (Sweden)

    Jingjing Yang

    2017-01-01

    Full Text Available This paper discusses the consistency of trend break point estimators when the number of breaks is underspecified. The consistency of break point estimators in a simple location model with level shifts has been well documented by researchers under various settings, including extensions such as allowing a time trend in the model. Despite the consistency of break point estimators of level shifts, there are few papers on the consistency of trend shift break point estimators in the presence of an underspecified break number. The simulation study and asymptotic analysis in this paper show that the trend shift break point estimator does not converge to the true break points when the break number is underspecified. In the case of two trend shifts, the inconsistency problem worsens if the magnitudes of the breaks are similar and the breaks are either both positive or both negative. The limiting distribution for the trend break point estimator is developed and closely approximates the finite sample performance.

  2. Locas al Rescate: The Transnational Hauntings of Queer Cubanidad

    Directory of Open Access Journals (Sweden)

    Lázaro Lima

    2011-12-01

    Full Text Available “Locas al Rescate: The Transnational Hauntings of Queer Cubanidad” (originally published in Cuba Transnational offers a significant contribution both to transnational American Studies and to gender studies. In telling the insider story of the alternative identity formation, practices, and forms of “rescue” initiated by the affective activism of the Cuban American society in drag in 1990s Miami/South Beach, Lima resuscitates the liberatory gestures of a subculture defined by its pursuit of its own acceptance, value, and freedom. With their aesthetic and political life on a raft, the gay micro-communities inside Cuban America asserted their own islandic space, Lima observes, performing “takeovers” in and of parks and bars and beaches—creating a post-Habermasian sphere of public activism focused on private parts, saving themselves from AIDS, from the disaffection and disaffiliation of the right-wing Cuban immigrant community, and from the failure of their own yearning to belong, to be wanted, to be embodied as the figure of their compelling Cubanidad. Against the hegemony of the invented collective politics of the sacrificing immigrants whose recognition of the queer side of being (of a being constituted by identity loss is yet to come, Lima suggests a spectral return—a personal and transnational reckoning of those whose lives the dream of freedom drowned.

  3. Nurses' perspectives on breaking bad news to patients and their families: a qualitative content analysis.

    Science.gov (United States)

    Abbaszadeh, Abbas; Ehsani, Seyyedeh Roghayeh; Begjani, Jamal; Kaji, Mohammad Akbari; Dopolani, Fatemeh Nemati; Nejati, Amir; Mohammadnejad, Esmaeil

    2014-01-01

    Breaking bad news is quite often not done in an effective manner in clinical settings due to the medical staff lacking the skills necessary for speaking to patients and their families. Bad news is faced with similar reactions on the part of the news receiver in all cultures and nations. The purpose of this study was to explore the perspectives of Iranian nurses on breaking bad news to patients and their families. In this research, a qualitative approach was adopted. In-depth and semi-structured interviews were conducted with 19 nurses who had at least one year work experience in the ward, and content analysis was performed to analyze the data. Five major categories emerged from data analysis, including effective communication with patients and their families, preparing the ground for delivering bad news, minimizing the negativity associated with the disease, passing the duty to physicians, and helping patients and their families make logical treatment decisions. The results of this study show that according to the participants, it is the physicians' duty to give bad news, but nurses play an important role in delivering bad news to patients and their companions and should therefore be trained in clinical and communicative skills to be able to give bad news in an appropriate and effective manner.

  4. Poisson structure and stability analysis of a coupled system arising from the supersymmetric breaking of Super KdV

    CERN Document Server

    Restuccia, A

    2014-01-01

    The Poisson structure of a coupled system arising from a supersymmetric breaking of N=1 Super KdV equations is obtained. The supersymmetric breaking is implemented by introducing a Clifford algebra instead of a Grassmann algebra. The Poisson structure follows from the Dirac brackets obtained by the constraint analysis of the hamiltonian of the system. The coupled system has multisolitonic solutions. We show that the one soliton solutions are Liapunov stable.

  5. Calculation of the frequency of excedence in Full Spectrum LOCA by FSR; Calculo de la Frecuencia de excedencia en Full Spectrum LOCA mediante metodologia ISA

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Magan, J. J.; Queral Salazar, C.; Sanchez Perea, M.

    2012-07-01

    In this application LOCA sequences was taken into account the uncertainty in the size of rupture and the operator action times as cooling and depressurization through steam generators. The simulations were performed using the tool SCAIS, dynamically coupled with MAAP code.

  6. Comparative analysis of several sediment transport formulations applied to dam-break flows over erodible beds

    Science.gov (United States)

    Cea, Luis; Bladé, Ernest; Corestein, Georgina; Fraga, Ignacio; Espinal, Marc; Puertas, Jerónimo

    2014-05-01

    Transitory flows generated by dam failures have a great sediment transport capacity, which induces important morphological changes on the river topography. Several studies have been published regarding the coupling between the sediment transport and hydrodynamic equations in dam-break applications, in order to correctly model their mutual interaction. Most of these models solve the depth-averaged shallow water equations to compute the water depth and velocity. On the other hand, a wide variety of sediment transport formulations have been arbitrarily used to compute the topography evolution. These are based on semi-empirical equations which have been calibrated under stationary and uniform conditions very different from those achieved in dam-break flows. Soares-Frazao et al. (2012) proposed a Benchmark test consisting of a dam-break over a mobile bed, in which several teams of modellers participated using different numerical models, and concluded that the key issue which still needs to be investigated in morphological modelling of dam-break flows is the link between the solid transport and the hydrodynamic variables. This paper presents a comparative analysis of different sediment transport formulations applied to dam-break flows over mobile beds. All the formulations analysed are commonly used in morphological studies in rivers, and include the formulas of Meyer-Peter & Müller (1948), Wong-Parker (2003), Einstein-Brown (1950), van Rijn (1984), Engelund-Hansen (1967), Ackers-White (1973), Yang (1973), and a Meyer-Peter & Müller type formula but with ad-hoc coefficients. The relevance of corrections on the sediment flux direction and magnitude due to the bed slope and the non-equilibrium hypothesis is also analysed. All the formulations have been implemented in the numerical model Iber (Bladé et al. (2014)), which solves the depth-averaged shallow water equations coupled to the Exner equation to evaluate the bed evolution. Two different test cases have been

  7. Retrosynthetic Analysis-Guided Breaking Tile Symmetry for the Assembly of Complex DNA Nanostructures.

    Science.gov (United States)

    Wang, Pengfei; Wu, Siyu; Tian, Cheng; Yu, Guimei; Jiang, Wen; Wang, Guansong; Mao, Chengde

    2016-10-11

    Current tile-based DNA self-assembly produces simple repetitive or highly symmetric structures. In the case of 2D lattices, the unit cell often contains only one basic tile because the tiles often are symmetric (in terms of either the backbone or the sequence). In this work, we have applied retrosynthetic analysis to determine the minimal asymmetric units for complex DNA nanostructures. Such analysis guides us to break the intrinsic structural symmetries of the tiles to achieve high structural complexities. This strategy has led to the construction of several DNA nanostructures that are not accessible from conventional symmetric tile designs. Along with previous studies, herein we have established a set of four fundamental rules regarding tile-based assembly. Such rules could serve as guidelines for the design of DNA nanostructures.

  8. Comparison of the phenomenology of SBO sequences with and without seals LOCA Westinghouse PWRs; Comparacion de la fenomenologia de las secuencias de SBO con y sin LOCA de sellos en reactores PWR Westinghouse

    Energy Technology Data Exchange (ETDEWEB)

    Mena Rosell, L.; Queral, C.; Jimenez Varas, G.

    2013-07-01

    SBO sequences have gained notoriety after the accident at Fukushima. Within this type of sequence the appearance or not of seals of the RCP LOCA determines the evolution of the accident. This work has been applied the methodology of integrated safety analysis (ISA), developed by the CSN, sequences of SBO. The objective is to compare the evolution of SBO sequences in a wide spectrum of conditions and recovery times of AC and DC loss. The simulations have been performed with the SCAIS tool coupled to MAAP. The set of simulations carried out, of the order of 2,000 sequences, clearly show the differences in the evolution of sequences with and without seals crazy. This type of analysis allows you to verify which would be the most appropriate management of sequence depending on the appearance or not of the MADWOMAN of seals.

  9. Analysis of heavy-ion-induced DNA strand breaks in plasmid pUC18

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Plasmid DNA was irradiated or implanted by mixed particle field(CR) or lithium-ion-beam to detect strand breaks.The primary results showed that mixed particle field could induce single and double strand breaks with positive linear-dose-effects;most of sequence changes induced by CR were point mutant.Lithium-ion-beam could induce strand breaks also,but it was only at dose of 20Gy.

  10. Mechanical Analysis of Taekwondo Power Break%跆拳道威力击破的力学分析

    Institute of Scientific and Technical Information of China (English)

    张智

    2013-01-01

      文章运用文献资料法、逻辑分析法等研究方法,阐明了跆拳道威力击破的相关力学原理,并运用相关的力学原理对威力击破的全过程进行科学的力学分析,为跆拳道的威力击破提供理论性依据,更好的把握威力击破的本质,达到最佳的击破效果。%This paper uses the methods of literature review, logical analysis to clarify the mechanics principles of Taekwondo power break, the mechanical principle of power break, the whole process of the scientific analysis of the mechanics, to provide a theoretical basis for Taekwondo power break, more good grasp of the essence of power break, to achieve the best break.

  11. Verification of human actions in SBO sequences with LOCA stamps in Westinghouse PWRs; Verificacion de las actuaciones humanas en secuencias de SBO con LOCA de sellos en reactores PWR Westinghouse

    Energy Technology Data Exchange (ETDEWEB)

    Queral, C.; Mena Rosell, L.; Jimenez Varas, G.

    2013-07-01

    The Fukushima accident has shown the need for tools and methodologies able to analyze human activities and / or capabilities of portable systems that has given the Spanish plants as a result of the stress tests . In this work we have applied the methodology of integrated safety analysis developed by the CSN , to SBO sequences with LOCA stamp. The aim is to show a methodology for testing the performances of the Emergency Operating Procedures and Guides Severe Accident Management. The simulations were performed with the tool SCAIS coupled to MAAP . The results show that there are human activities that may be beneficial in certain sequences but harmful in others. This type of problem is already known and referred to in the GGAS . However, FSR shows a practical way to check human actions cannot be obtained with other methods.

  12. HCCR TBS safety analysis - HCS Heat Exchanger Break to CCWS-1

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Hyung Gon; Lee, Dong Won; Lee, Eo Hwak; Yoon, Jae Sung; Kim, Suk Kwon; Ahn, Mu-Young [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Cho, Seungyon [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    This paper presents the accident analyses results of helium pipe rupture in main HX to CCWS-1, which is category I chit for the conceptual design of HCCR-TBS. To confirm the HCCR-TBS integrity, enveloped cases from the conceivable events were evaluated and demonstrated compliance with the General Safety Objectives of ITER. In principle, transient of this accident is similar to LOHSA, therefore, TBM temperature is expected to be cool down by passive cooling and isolation valves avoid CCWS-1 pressure build-up during the accident. With relief valve, pressure of CCWS-1 is under 0.43 MPa during LOCA happens. (CCWS-1 max. design pressure: 1MPa). On the other hand, primary concern is tritium concentration increase in CCWS-1 because of tritium contents in HCS coolant. The important point is that CCWS-1 is an ESP device and its ESP level should be confirmed when operating with HCCR-TBS as well. ESP/ESPN classification check is valid in an incident, however, conservatively tritium concentration of whole system including CCWS-1 was examined during this accident. In total, 20 years operation + accident case = 0.21 MBq/m{sup 3} + 0.35 MBq/m{sup 3} < 10 MBq/m{sup '}3.

  13. Simulation of containment pressurization in a large break-loss of coolant accident using single-cell and multicell models and CONTAIN code

    Energy Technology Data Exchange (ETDEWEB)

    Kalkahoran, Omid Noori; Ahangari, Rohollah [Reactor Research School, Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of); Shirani, Amir Saied [Faculty of Engineering, Shahid Beheshti University, Tehran (Iran, Islamic Republic of)

    2016-10-15

    Since the inception of nuclear power as a commercial energy source, safety has been recognized as a prime consideration in the design, construction, operation, maintenance, and decommissioning of nuclear power plants. The release of radioactivity to the environment requires the failure of multiple safety systems and the breach of three physical barriers: fuel cladding, the reactor cooling system, and containment. In this study, nuclear reactor containment pressurization has been modeled in a large break-loss of coolant accident (LB-LOCA) by programming single-cell and multicell models in MATLAB. First, containment has been considered as a control volume (single-cell model). In addition, spray operation has been added to this model. In the second step, the single-cell model has been developed into a multicell model to consider the effects of the nodalization and spatial location of cells in the containment pressurization in comparison with the single-cell model. In the third step, the accident has been simulated using the CONTAIN 2.0 code. Finally, Bushehr nuclear power plant (BNPP) containment has been considered as a case study. The results of BNPP containment pressurization due to LB-LOCA have been compared between models, final safety analysis report, and CONTAIN code's results.

  14. Assessing the impact of the dispersion of fuel in case of LOCA; Evaluacion del impacto de la dispersion de combustible en caso de LOCA

    Energy Technology Data Exchange (ETDEWEB)

    Concejal, A.; Garcia Sedano, P. J.; Crespo, A.

    2013-07-01

    Recent studies conducted in Halden and Studsvik have indicated the possibility of obtaining highly fragmented fuel with relatively low temperatures (700 degree centigrade) and high burned (70 MWd / kgU). In case of accident loss of coolant (LOCA), the expulsion may occur outside the pod fuel fragments, which can affect the coolability, cause channel blockade and therefore an increase in the maximum temperature of sheath.

  15. A Sensitivity Analysis of a Pipe Break Accident in a Preliminary Specific Design of the PGSFR

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kwi Lim; Jeong, Jae Ho; Ha, Kwi Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    The PGSFR (Prototype Gen-IV Sodium-cooled Fast Reactor) is a pool type sodium cooled fast reactor with a thermal power of 392.1 MW which has been developed in accord with an enhanced safety, an efficient utilization of uranium resources and a reduction of a high level waste volume in the Korea Atomic Energy Research Institute (KAERI) since 2012 under a National Nuclear R and D Program. The PGSFR has an inherent safety characteristic owing to the design to have a negative power reactivity coefficient during all operation modes and it has a passive safety characteristic due to the design of a passive decay heat removal circuit. In order to assess the inherent safety features of the PGSFR, a safety analysis was performed for a pipe break accident with MARS-LMR. And, the sensitivity studies were also performed to find the most conservative condition. As a result, the PGSFR was appropriately tripped by a high power to PHTS flow ratio using the method of extracting the PHTS flow rate from the pressure drop. The air flow rate was the most sensitive variable in the sensitivity analysis. Therefore, it is important to know the accurate uncertainty of the air flow rate in the AHX.

  16. Numerical analysis on coal-breaking process under high pressure water jet

    Institute of Scientific and Technical Information of China (English)

    CHEN Jin-hua; LIANG Yun-pei; CHENG Guo-qiang

    2009-01-01

    Based on the theory of nonlinear dynamic finite element, the control equation of coal and water jet was acquired in the coal breaking process under a water jet. The calcu-lation model of coal breaking under a water jet was established; the fluid-structure cou-pling of water jet and coal was implemented by penalty function and convection calculation. The dynamic process of coal breaking under a water jet was simulated and analyzed by combining the united fracture criteria of the maximum tensile strain and the maximal shear strain in the two cases of damage to coal and damage failure to coal.

  17. Aging and loss-of-coolant accident (LOCA) testing of electrical connections

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, C.F. [Sandia National Labs., Albuquerque, NM (United States)

    1998-01-01

    This report presents the results of an experimental program to determine the aging and loss-of-coolant accident (LOCA) behavior of electrical connections in order to obtain an initial scoping of their performance. Ten types of connections commonly used in nuclear power plants were tested. These included 3 types of conduit seals, 2 types of cable-to-device connectors, 3 types of cable-to-cable connectors, and 2 types of in-line splices. The connections were aged for 6 months under simultaneous thermal (99 C) and radiation (46 Gy/hr) conditions. A simulated LOCA consisting of sequential high dose-rate irradiation (3 kGy/hr) and high-temperature steam exposures followed the aging. Connection functionality was monitored using insulation resistance measurements during the aging and LOCA exposures. Because only 5 of the 10 connection types passed a post-LOCA, submerged dielectric withstand test, further detailed investigation of electrical connections and the effects of cable jacket integrity on the cable-connection system is warranted.

  18. Downscaling humidity with Localized Constructed Analogs (LOCA) over the conterminous United States

    Science.gov (United States)

    Pierce, D. W.; Cayan, D. R.

    2016-07-01

    Humidity is important to climate impacts in hydrology, agriculture, ecology, energy demand, and human health and comfort. Nonetheless humidity is not available in some widely-used archives of statistically downscaled climate projections for the western U.S. In this work the Localized Constructed Analogs (LOCA) statistical downscaling method is used to downscale specific humidity to a 1°/16° grid over the conterminous U.S. and the results compared to observations. LOCA reproduces observed monthly climatological values with a mean error of ~0.5 % and RMS error of ~2 %. Extreme (1-day in 1- and 20-years) maximum values (relevant to human health and energy demand) are within ~5 % of observed, while extreme minimum values (relevant to agriculture and wildfire) are within ~15 %. The asymmetry between extreme maximum and minimum errors is largely due to residual errors in the bias correction of extreme minimum values. The temporal standard deviations of downscaled daily specific humidity values have a mean error of ~1 % and RMS error of ~3 %. LOCA increases spatial coherence in the final downscaled field by ~13 %, but the downscaled coherence depends on the spatial coherence in the data being downscaled, which is not addressed by bias correction. Temporal correlations between daily, monthly, and annual time series of the original and downscaled data typically yield values >0.98. LOCA captures the observed correlations between temperature and specific humidity even when the two are downscaled independently.

  19. Analysis of nanosecond breaking of a high-density current in SOS diodes

    Science.gov (United States)

    Grekhov, I. V.; Lyublinskii, A. G.; Smirnova, I. A.

    2015-11-01

    Effect of a sharp (nanosecond) breaking of the reverse current with a density on the order of 103-104 A/cm2 in a silicon diode upon switching from direct to reverse bias voltage (so-called silicon opening switch, or SOS effect) is widely used in nanosecond technologies of gigawatt powers. For detailed analysis of the SOS effect, we constructed a special setup with small stray inductance, which makes it possible to test single SOS diodes with a working area of 1-2 mm2 in a wide range of current densities. Our experiments show, in particular, that the numerical model of the SOS effect developed at the Institute of Electrophysics, Ural Branch, Russian Academy of Sciences successfully described the experimental results. It is also shown that the charge extracted from the diode structure by the reverse current exceeds the charge introduced by a direct current pulse by not more than 10%, indicating a relatively small role of ionization processes. The possibility to carry out experiments on single samples with a small surface area allows us to study the SOS effect and considerably facilitates investigations aimed at the perfection of the design of SOS diodes.

  20. Multiple-pathway analysis of double-strand break repair mutations in Drosophila.

    Directory of Open Access Journals (Sweden)

    Dena M Johnson-Schlitz

    2007-04-01

    Full Text Available The analysis of double-strand break (DSB repair is complicated by the existence of several pathways utilizing a large number of genes. Moreover, many of these genes have been shown to have multiple roles in DSB repair. To address this complexity we used a repair reporter construct designed to measure multiple repair outcomes simultaneously. This approach provides estimates of the relative usage of several DSB repair pathways in the premeiotic male germline of Drosophila. We applied this system to mutations at each of 11 repair loci plus various double mutants and altered dosage genotypes. Most of the mutants were found to suppress one of the pathways with a compensating increase in one or more of the others. Perhaps surprisingly, none of the single mutants suppressed more than one pathway, but they varied widely in how the suppression was compensated. We found several cases in which two or more loci were similar in which pathway was suppressed while differing in how this suppression was compensated. Taken as a whole, the data suggest that the choice of which repair pathway is used for a given DSB occurs by a two-stage "decision circuit" in which the DSB is first placed into one of two pools from which a specific pathway is then selected.

  1. Theoretical analysis and experimental study of oxygen transfer under regular and non-breaking waves

    Institute of Scientific and Technical Information of China (English)

    尹则高; 梁丙臣; 王乐

    2013-01-01

    The dissolved oxygen concentration is an important index of water quality, and the atmosphere is one of the important sources of the dissolved oxygen. In this paper, the mass conservation law and the dimensional analysis method are employed to study the oxygen transfer under regular and non-breaking waves, and a unified oxygen transfer coefficient equation is obtained with consi-deration of the effect of kinetic energy and wave period. An oxygen transfer experiment for the intermediate depth water wave is per-formed to measure the wave parameters and the dissolved oxygen concentration. The experimental data and the least squares method are used to determine the constant in the oxygen transfer coefficient equation. The experimental data and the previous reported data are also used to further validate the oxygen transfer coefficient, and the agreement is satisfactory. The unified equation shows that the oxygen transfer coefficient increases with the increase of a parameter coupled with the wave height and the wave length, but it de-creases with the increase of the wave period, which has a much greater influence on the oxygen transfer coefficient than the coupled parameter.

  2. Proteome analysis of Norway maple (Acer platanoides L. seeds dormancy breaking and germination: influence of abscisic and gibberellic acids

    Directory of Open Access Journals (Sweden)

    Pawłowski Tomasz A

    2009-05-01

    Full Text Available Abstract Background Seed dormancy is controlled by the physiological or structural properties of a seed and the external conditions. It is induced as part of the genetic program of seed development and maturation. Seeds with deep physiological embryo dormancy can be stimulated to germinate by a variety of treatments including cold stratification. Hormonal imbalance between germination inhibitors (e.g. abscisic acid and growth promoters (e.g. gibberellins is the main cause of seed dormancy breaking. Differences in the status of hormones would affect expression of genes required for germination. Proteomics offers the opportunity to examine simultaneous changes and to classify temporal patterns of protein accumulation occurring during seed dormancy breaking and germination. Analysis of the functions of the identified proteins and the related metabolic pathways, in conjunction with the plant hormones implicated in seed dormancy breaking, would expand our knowledge about this process. Results A proteomic approach was used to analyse the mechanism of dormancy breaking in Norway maple seeds caused by cold stratification, and the participation of the abscisic (ABA and gibberellic (GA acids. Forty-four proteins showing significant changes were identified by mass spectrometry. Of these, eight spots were identified as water-responsive, 18 spots were ABA- and nine GA-responsive and nine spots were regulated by both hormones. The classification of proteins showed that most of the proteins associated with dormancy breaking in water were involved in protein destination. Most of the ABA- and GA-responsive proteins were involved in protein destination and energy metabolism. Conclusion In this study, ABA was found to mostly down-regulate proteins whereas GA up-regulated proteins abundance. Most of the changes were observed at the end of stratification in the germinated seeds. This is the most active period of dormancy breaking when seeds pass from the quiescent

  3. Differentiation and analysis on rock breaking characteristics of TBM disc cutter at different rock temperatures

    Institute of Scientific and Technical Information of China (English)

    谭青; 张桂菊; 夏毅敏; 李建芳

    2015-01-01

    In order to study rock breaking characteristics of tunnel boring machine (TBM) disc cutter at different rock temperatures, thermodynamic rock breaking mathematical model of TBM disc cutter was established on the basis of rock temperature change by using particle flow code theory and the influence law of interaction mechanism between disc cutter and rock was also numerically simulated. Furthermore, by using the linear cutting experiment platform, rock breaking process of TBM disc cutter at different rock temperatures was well verified by the experiments. Finally, rock breaking characteristics of TBM disc cutter were differentiated and analyzed from microscale perspective. The results indicate the follows. 1) When rock temperature increases, the mechanical properties of rock such as hardness, and strength, were greatly reduced, simultaneously the microcracks rapidly grow with the cracks number increasing, which leads to rock breaking load decreasing and improves rock breaking efficiency for TBM disc cutter. 2) The higher the rock temperature, the lower the rock internal stress. The stress distribution rules coincide with the Buzin Neske stress circle rules: the maximum stress value is below the cutting edge region and then gradually decreases radiant around; stress distribution is symmetrical and the total stress of rock becomes smaller. 3) The higher the rock temperature is, the more the numbers of micro, tensile and shear cracks produced are by rock as well as the easier the rock intrusion, along with shear failure mode mainly showing. 4) With rock temperature increasing, the resistance intrusive coefficients of rock and intrusion power decrease obviously, so the specific energy consumption that TBM disc cutter achieves leaping broken also decreases subsequently. 5) The acoustic emission frequency remarkably increases along with the temperature increasing, which improves the rock breaking efficiency.

  4. Exploration of Shape Variation Using Localized Components Analysis

    OpenAIRE

    Alcantara, Dan A; Carmichael, Owen; Harcourt-Smith, Will; Sterner, Kirstin; Frost, Stephen R.; Dutton, Rebecca; Thompson, Paul; Delson, Eric; Amenta, Nina

    2009-01-01

    Localized Components Analysis (LoCA) is a new method for describing surface shape variation in an ensemble of objects using a linear subspace of spatially localized shape components. In contrast to earlier methods, LoCA optimizes explicitly for localized components and allows a flexible trade-off between localized and concise representations, and the formulation of locality is flexible enough to incorporate properties such as symmetry. This paper demonstrates that LoCA can provide intuitive p...

  5. Development of safety analysis codes and experimental validation for a very high temperature gas-cooled reactor Final report

    Energy Technology Data Exchange (ETDEWEB)

    Chang Oh

    2006-03-01

    The very high-temperature gas-cooled reactor (VHTR) is envisioned as a single- or dual-purpose reactor for electricity and hydrogen generation. The concept has average coolant temperatures above 9000C and operational fuel temperatures above 12500C. The concept provides the potential for increased energy conversion efficiency and for high-temperature process heat application in addition to power generation. While all the High Temperature Gas Cooled Reactor (HTGR) concepts have sufficiently high temperature to support process heat applications, such as coal gasification, desalination or cogenerative processes, the VHTR’s higher temperatures allow broader applications, including thermochemical hydrogen production. However, the very high temperatures of this reactor concept can be detrimental to safety if a loss-of-coolant accident (LOCA) occurs. Following the loss of coolant through the break and coolant depressurization, air will enter the core through the break by molecular diffusion and ultimately by natural convection, leading to oxidation of the in-core graphite structure and fuel. The oxidation will accelerate heatup of the reactor core and the release of toxic gasses (CO and CO2) and fission products. Thus, without any effective countermeasures, a pipe break may lead to significant fuel damage and fission product release. Prior to the start of this Korean/United States collaboration, no computer codes were available that had been sufficiently developed and validated to reliably simulate a LOCA in the VHTR. Therefore, we have worked for the past three years on developing and validating advanced computational methods for simulating LOCAs in a VHTR. Research Objectives As described above, a pipe break may lead to significant fuel damage and fission product release in the VHTR. The objectives of this Korean/United States collaboration were to develop and validate advanced computational methods for VHTR safety analysis. The methods that have been developed are now

  6. Effect of thermal aging on the leak-before-break analysis of nuclear primary pipes

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Xuming; Li, Shilei [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Wang, Xitao [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Collaborative Innovation Center of Steel Technology, University of Science and Technology Beijing, Beijing 100083 (China); Wang, Yanli [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Wang, Zhaoxi [CPI Nuclear Power Institute, 18 Xizhimen St., Beijing 100044 (China); Xue, Fei [Suzhou Nuclear Power Research Institute, Suzhou 215004 (China); Zhang, Hailong, E-mail: hlzhang@ustb.edu.cn [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China)

    2014-12-15

    Highlights: • Thermal aging embrittlement is considered in LBB assessment of nuclear pipe. • Effect of thermal aging on growth behavior of partial-through crack is not obvious. • Detectable leakage crack length of thermally aged material is slightly increased. • Critical crack length of thermally aged material is significantly reduced. • Ignorance of thermal aging produces less conservative LBB results. - Abstract: Three-dimensional finite element analysis (FEA) models were built for pipes with circumferential cracks and the effect of thermal aging embrittlement on the leak-before-break (LBB) behavior was analyzed according to the Level 2 and Level 3 safety assessments. The detectable leakage crack length obtained using the two-phase critical flow model and the critical crack length calculated by the J-integral stability assessment diagram method were carried out to assess the LBB behavior. The propagation behavior of partial-through circumferential cracks for both unaged and thermally aged materials was estimated by testing fatigue crack growth rate. The results show that the effect of thermal aging on detectable leakage crack length is not obvious, whereas the critical crack length after thermal aging significantly decreases due to degradation of fracture toughness. The increments of partial-through cracks are insignificant after 40 years of service. In the Level 2 and Level 3 safety assessments for nuclear piping, LBB is shown to have sufficient safety margins, while it is suggested to decrease in the case of thermal aging. This work demonstrates that less conservative LBB assessment results will be produced if thermal aging embrittlement in piping steels is not taken into consideration.

  7. Thermal-Hydraulic Assessment of W7-X Plasma Vessel Venting System in Case of 40 mm In-Vessel LOCA

    Directory of Open Access Journals (Sweden)

    E. Urbonavičius

    2015-01-01

    Full Text Available This paper presents assessment of the capacity of W7-X venting system in response to in-vessel LOCA, rupture of 40 mm diameter pipe during operation mode “baking.” The integral analysis of the coolant release from the cooling system, pressurisation of PV, and response of the venting system is performed using RELAP5 code. The same coolant release rate was introduced to the COCOSYS code, which is a lumped-parameter code developed for analysis of processes in containment of the light water reactors and the detailed analysis of the plasma vessel and the venting system is performed. Different options of coolant release modeling available in COCOSYS are compared to define the base case model, which is further used for assessment of the other parameters, that is, the failure of one burst disk, the temperature in the environment, and the pressure losses in the piping of venting system. The performed analysis identified the best option for coolant release modeling and showed that the capacity of the W7-X venting system is enough to prevent overpressure of the plasma vessel in the case of in-vessel LOCA.

  8. THE RELATIONSHIP BETWEEN ENERGY CONSUMPTION AND ECONOMIC GROWTH: EVIDENCE FROM A STRUCTURAL BREAK ANALYSIS FOR TURKEY

    Directory of Open Access Journals (Sweden)

    Yasemin Dumrul

    2013-01-01

    Full Text Available In this study the aim was to investigate empirically the role of energy consumption in economic growth for the Turkish economy. The data used include annual energy consumption and economic growth series from 1960 to 2008. We used aggregate as well as various disaggregate data on energy consumption, including, oil, electricity, coal and renewable energy. Our contribution is that we take a structural breaks modeling approach in this paper. In the literature, the Kejriwal cointegration test has not been applied to date. The main conclusion of the study was that Turkey’s energy consumption and economic growth has a positive relationship varying quantity with structural breaks.

  9. Break It

    Institute of Scientific and Technical Information of China (English)

    MATTHEW PLOWRIGHT; GWYNN GUILFORD

    2008-01-01

    @@ Resolutions are not natural - otherwise you wouldn't have to "resolve" to execute them. This year, instead of planning how to commit to a slew of unattainable goals, why not prepare for breaking your resolutions the right way?

  10. Generic Safety Issue (GSI) 171 -- Engineered Safety Feature (ESF) failure from a loop subsequent to LOCA: Assessment of plant vulnerability and CDF contributions

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Guridi, G.; Samanta, P.; Chu, L.; Yang, J. [Brookhaven National Lab., Upton, NY (United States)

    1998-03-01

    Generic Safety Issue 171 (GSI-171), Engineered Safety Feature (ESF) from a Loss Of Offsite Power (LOOP) subsequent to a Loss Of Coolant Accident (LOCA), deals with an accident sequence in which a LOCA is followed by a LOOP. This issue was later broadened to include a LOOP followed by a LOCA. Plants are designed to handle a simultaneous LOCA and LOOP. In this paper, the authors address the unique issues that are involved i LOCA with delayed LOOP (LOCA/LOOP) and LOOP with delayed LOCA (LOOP/LOCA) accident sequences. LOCA/LOOP accidents are analyzed further by developing event-tree/fault-tree models to quantify their contributions to core-damage frequency (CDF) in a pressurized water reactor and a boiling water reactor (PWR and a BWR). Engineering evaluation and judgments are used during quantification to estimate the unique conditions that arise in a LOCA/LOOP accident. The results show that the CDF contribution of such an accident can be a dominant contributor to plant risk, although BWRs are less vulnerable than PWRs.

  11. Statistical methods for the analysis of safety margins by BE + U codes; Metodos estasticos para el analisis de margenes de seguridad mediante codigos BE+U

    Energy Technology Data Exchange (ETDEWEB)

    Villamizar, M.; Martorell, S.; Villanueva, J. F.; Carlos, S.; Sanchez, A.; Pelayo, F.; Mendizabal, R.; Sol, I.

    2012-11-01

    Statistical methods for the analysis of safety margins through BE+U codes: This paper presents tools for statistical analysis (PLS, PCS,Variance Decomposition) to understand the relationships between input variables (defined by parameters of the model thermal-hydraulics distribution functions) and output variable, e. g. the PCT variable. The objective is to identify the most important input variables in order to the effect on the output variables. In addition, it is possible to quantify the contribution of the uncertainty of each input variable in the uncertainly of results. the case of application develops a Large Break LOCA in PWR. (Author) 16 refs.

  12. Breaking through the Advertising Clutter: A Qualitative Analysis of Broken Stereotypes in Print and Television Advertisements.

    Science.gov (United States)

    Larson, Charles U.

    As a result of the overwhelming amount of print and electronic advertisements which compete for consumer attention, advertisers must find effective methods to get through the ad clutter and capture their audience's interest. Several tactics can accomplish this strategy, including the tactic of breaking or reversing audience expectations or…

  13. Perspectives on the Application of Order-Statistics in Best-Estimate Plus Uncertainty Nuclear Safety Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Robert P. Martin; William T. Nutt

    2011-01-01

    The application of order-statistics in best-estimate plus uncertainty nuclear safety analysis has received a considerable amount of attention from methodology practitioners, regulators, and academia. At the root of the debate are two questions: (1) what is an appropriate quantitative interpretation of “high level of probability” in regulatory language appearing in the LOCA rule, 10 CFR 50.46 and (2) how best to mathematically characterize the multi-variate case. An original derivation is offered to provide a quantitative basis for “high level of probability.” At root of the second question is whether one should recognize a probability statement based on the tolerance region method of Wald and Guba, et al., for multi-variate problems, one explicitly based on the regulatory limits, best articulated in the Wallis–Nutt “Testing Method”, or something else entirely. This paper reviews the origins of the different positions, key assumptions, limitations, and relationship to addressing acceptance criteria. It presents a mathematical interpretation of the regulatory language, including a complete derivation of uni-variate order-statistics (as credited in AREVA’s Realistic Large Break LOCA methodology) and extension to multi-variate situations. Lastly, it provides recommendations for LOCA applications, endorsing the “Testing Method” and addressing acceptance methods allowing for limited sample failures.

  14. Flow regimes and heat transfer modes identification in ANGRA 2 core, during small break in the primary loop with area of 100 cm{sup 2}, simulated with RELAP5 code

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Eduardo M.; Sabundjian, Gaiane, E-mail: gdgian@ipen.br, E-mail: borges.em@hotmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Identifying the flow regimes and the heat transfer modes is important for the analysis of accidents such as the Loss-of-Coolant Accident (LOCA). The aim of this paper is to identify the flow regimes, the heat transfer modes, and the correlations used in the RELAP5/MOD3.2.gama code in ANGRA 2 during the Small-Break Loss-of-Coolant Accident (SBLOCA) with a 100cm{sup 2}-rupture area in the cold leg of primary loop. The Chapter 15 of the Final Safety Analysis Report of ANGRA 2 (FSAR - A2) reports this specific kind of accident. The results from this work demonstrated the several flow regimes and heat transfer modes that can be present in the core of ANGRA 2 during the postulated accident. (author)

  15. Experimental investigation on the causes for pellet fragmentation under LOCA conditions

    Science.gov (United States)

    Bianco, A.; Vitanza, C.; Seidl, M.; Wensauer, A.; Faber, W.; Macián-Juan, R.

    2015-10-01

    This paper addresses a separate effect experiment performed with irradiated fuel to study fuel fragmentation and fission gas release during a loss of coolant accident (LOCA). The paper presents a qualitative and quantitative investigation of the effects of the removal of the geometrical constraint provided by the cladding and the removal of the constraint given by the rod internal pressure in determining the extent of fuel fragmentation and fission gas release during a LOCA for fuel segments with a burnup of approximately 52 MWd/kgU. A review of previous LOCA tests was the starting point for the identification of these constraints and for the selection of the fuel rod burnup, the experiment's procedure and the boundary conditions. An out-of-pile test was considered representative for the scope, and the experiment was performed at the Halden Reactor Project hot cell in Kjeller (Norway) with heat provided by an electric oven. Three fuel rod segments were studied: 1) a fuel segment that experienced only ballooning without burst, 2) a fuel segment that experienced ballooning and burst and 3) a fuel segment that experienced neither ballooning nor burst. The neutron radiography and fuel fragment sifting showed that both cladding constraint and internal pressure play a role in the formation of fuel cracks and fragmentation, and the study of the fission gas release during the transient showed that removing the cladding constraint or the internal pressure increased the amount of fission gas release.

  16. Interfacing systems LOCAs (Loss of Coolant Accidents) at boiling water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Tsong-Lun; Fitzpatrick, R.; Stoyanov, S.

    1987-01-01

    The work presented in this paper was performed by Brookhaven National Laboratory (BNL) in support of Nuclear Regulatory Commission's (NRC) effort towards the resolution of Generic Issue 105 ''Interfacing System Loss of Coolant Accidents (LOCAs) at Boiling Water Reactors (BWRs).'' For BWRs, intersystem LOCA have typically either not been considered in probabilistic risk analyses, or if considered, were judged to contribute little to the risk estimates because of their perceived low frequency of occurrence. However, recent operating experience indicates that the pressure isolation valves (PIVs) in BWRs may not adequately protect against overpressurization of low pressure systems. The objective of this paper is to present the results of a study which analyzed interfacing system LOCA at several BWRs. The BWRs were selected to best represent a spectrum of BWRs in service using industry operating event experience and plant-specific information/configurations. The results presented here include some possible changes in test requirements/practices as well as an evaluation of their reduction potential in terms of core damage frequency (CDF).

  17. Long-term aging and loss-of-coolant accident (LOCA) testing of electrical cables

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, C.F.; Gauthier, G.; Carlin, F. [and others

    1996-10-01

    Experiments were performed to assess the aging degradation and loss-of-coolant accident (LOCA) behavior of electrical cables subjected to long-term aging exposures. Four different cable types were tested in both the U.S. and France: (1) U.S. 2 conductor with ethylene propylene rubber (EPR) insulation and a Hypalon jacket. (2) U.S. 3 conductor with cross-linked polyethylene (XLPE) insulation and a Hypalon jacket. (3) French 3 conductor with EPR insulation and a Hypalon jacket. (4) French coaxial with polyethylene (PE) insulation and a PE jacket. The data represent up to 5 years of simultaneous aging where the cables were exposed to identical aging radiation doses at either 40{degrees}C or 70{degrees}C; however, the dose rate used for the aging irradiation was varied over a wide range (2-100 Gy/hr). Aging was followed by exposure to simulated French LOCA conditions. Several mechanical, electrical, and physical-chemical condition monitoring techniques were used to investigate the degradation behavior of the cables. All the cables, except for the French PE cable, performed acceptably during the aging and LOCA simulations. In general, cable degradation at a given dose was highest for the lowest dose rate, and the amount of degradation decreased as the dose rate was increased.

  18. An analysis of the importance of appropriate tie breaking rules in dispatch heuristics

    Directory of Open Access Journals (Sweden)

    Jorge M. S. Valente

    2006-04-01

    Full Text Available In this paper, we analyse the effect of using appropriate tie breaking criteria in dispatch rules. We consider four different dispatch procedures, and for each of these heuristics we compare two versions that differ only in the way ties are broken. The first version breaks ties randomly, while the second uses a criterion that incorporates problem-specific knowledge. The computational results show that using adequate tie breaking criteria improves the performance of the dispatch heuristics. The magnitude of the improvement is different for the four heuristics, and also depends on the characteristics of each specific instance. The use of problem-related knowledge for breaking ties should therefore be given some consideration in the implementation of dispatch rules.Neste artigo é analisado o efeito da utilização de regras de desempate apropriadas na eficácia de regras de despacho. São consideradas quatro regras de despacho diferentes, e para cada uma destas heurísticas são comparadas duas versões que diferem no modo como os empates são resolvidos. A primeira versão resolve os empates de forma aleatória, enquanto a segunda utiliza um critério que incorpora informação relativa ao problema em causa. Os resultados computacionais mostram que a utilização de critérios de desempate adequados melhora o desempenho das regras de despacho. A magnitude da melhoria é diferente para as quatro heurísticas, e depende igualmente das características específicas de cada instância. A utilização de informação relativa ao problema em causa para a resolução de empates deve assim ser considerada na implementação de regras de despacho.

  19. Fluorometric analysis of the formation and repair of DNA breaks in irradiated cells

    Energy Technology Data Exchange (ETDEWEB)

    Ryabchenko, N.I.; Proskuryakov, S.Ya.; Ivannik, B.P.; Kutmin, A.I. (Akademiya Meditsinskikh Nauk SSSR, Obninsk. Nauchno-Issledovatel' skij Inst. Meditsinskoj Radiologii)

    A study was made of the dependence of the fluorescence of ethidium bromide upon NaOH concentration after staining of single- and double-strand DNA in cell lysates was demonstrated. The method of fluorometry was used to study the dose dependence of a change in the share of double-stranded DNA in the irradiated thymocytes and Ehrlich ascites carcinoma cells which permitted to determine the appearance and repair of DNA breaks in these cells.

  20. The purchasing power parity in emerging Europe: Empirical results based on two-break analysis

    Directory of Open Access Journals (Sweden)

    Mladenović Zorica

    2013-01-01

    Full Text Available The purpose of the paper is to evaluate the validity of purchasing power parity (PPP for eight countries from the Emerging Europe: Hungary, Czech Republic, Poland, Romania, Lithuania, Latvia, Serbia and Turkey. Monthly data for euro and U.S. dollar based real exchange rate time series are considered covering the period: January, 2000 - August, 2011. Given significant changes in these economies in this sample it seems plausible to assume that real exchange time series are characterized by more than one time structural break. In order to endogenously determine the number and type of breaks while testing for the presence of unit roots we applied the Lee-Strazicich approach. For two euro based real exchange rate time series (in Hungary and Turkey the unit root hypothesis has been rejected. For the U.S. dollar based real exchange rate time series in Poland, Romania and Turkey the presence of unit root has been rejected. To assess the adjustment dynamics of those real exchange rates that were detected to be stationary with two breaks, the impulse response function is calculated and half-life is estimated. Our overall conclusion is that the persistence of real exchange rate in Emerging Europe is still substantially high. The lack of strong empirical support for PPP suggests that careful policy actions are needed in this region to prevent serious exchange rate misalignment.

  1. International Standard Problems and Small Break Loss-of-Coolant Accident (SBLOCA

    Directory of Open Access Journals (Sweden)

    N. Aksan

    2008-01-01

    Full Text Available Best-estimate thermal-hydraulic system codes are widely used to perform safety and licensing analyses of nuclear power plants and also used in the design of advance reactors. Evaluation of the capabilities and the performance of these codes can be accomplished by comparing the code predictions with measured experimental data obtained on different test facilities. OECD/NEA Committee on the Safety of Nuclear Installations (CSNI has promoted, over the last twenty-nine years, some forty-eight international standard problems (ISPs. These ISPs were performed in different fields as in-vessel thermal-hydraulic behaviour, fuel behaviour under accident conditions, fission product release and transport, core/concrete interactions, hydrogen distribution and mixing, containment thermal-hydraulic behaviour. 80% of these ISPs were related to the working domain of principal working group no.2 on coolant system behaviour (PWG2 and were one of the major PWG2 activities for many years. A global review and synthesis on the contribution that ISPs have made to address nuclear reactor safety issues was initiated by CSNI-PWG2 and an overview on the subject of small break LOCA ISPs is given in this paper based on a report prepared by a writing group. In addition, the relevance of small break LOCA in a PWR with relation to nuclear reactor safety and the reorientation of the reactor safety program after TMI-2 accident are shortly summarized. The experiments in four integral test facilities, LOBI, SPES, BETHSY, ROSA IV/LSTF and the recorded data during a steam generator tube rupture transient in the DOEL-2 PWR (Belgium were the basis of the five small break LOCA related ISP exercises, which deal with the phenomenon typical of small break LOCAs in Western design PWRs. Some lessons learned from these small break LOCA ISPs are identified in relation to code deficiencies and capabilities, progress in the code capabilities, possibility of scaling, and various additional aspects

  2. Pre-test analysis of an integral effect test facility for thermal hydraulic similarities of 6 inches cold leg break and DVI line break using MARS-1D

    Energy Technology Data Exchange (ETDEWEB)

    Ah, D. J.; Park, H. S.; Choi, K. Y.; Kwon, T. S.; Baek, W. P. [KAERI, Taejon (Korea, Republic of)

    2002-05-01

    Pre-test analyses of a small-break loss-of-coolant accident (SBLOCA) and a DVI line break accident, have been performed for the integral effect test loop of Korea Atomic Energy Research Institute (KAERI-ITL), the construction of which will be started soon. The KAERI-ITL is being designed with a full-height and 1/310 volume scale based on the design features of the APR1400 (Korean Next Generation Reactor). Based on the same control logics and accident scenarios, the similarity between the KAERI-ITL and the prototype plant, APR1400, is evaluated using the MARS code. It is found that the KAERI-ITL and APR1400 have similar thermal hydraulic responses during the transient under the identical accident scenarios. It is also verified that the volume scaling law, applied to the design of the KAERI-ITL, gives reasonable results to keep the similarity between APR1400 and KAERI-ITL.

  3. SU-C-BRE-07: Sensitivity Analysis of the Threshold Energy for the Creation of Strand Breaks and of Single and Double Strand Break Clustering Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Pater, P [I El Naqa, J Seuntjens, McGill University, Montreal, Quebec (Canada)

    2014-06-15

    Purpose: To analyse the sensitivity of the creation of strand breaks (SB) to the threshold energy (Eth) and thresholding method and to quantify the impact of clustering conditions on single strand break (SSB) and double strand break (DSB) yields. Methods: Monte Carlo simulations using Geant4-DNA were conducted for electron tracks of 280 eV to 220 keV in a geometrical DNA model composed of nucleosomes of 396 phospho-diester groups (PDGs) each. A strand break was created inside a PDG when the sum of all energy deposits (method 1) or energy transfers (method 2) was higher than Eth or when at least one interaction deposited (method 3) or transferred (method 4) an energy higher than Eth. SBs were then clustered into SSBs and DSBs using clustering scoring criteria from the literature and compared to our own. Results: The total number of SBs decreases as Eth is increased. In addition, thresholding on the energy transfers (methods 2 and 4) produces a higher SB count than when thresholding on energy deposits (methods 1 and 3). Method 2 produces a step-like function and should be avoided when attempting to optimize Eth. When SBs are grouped into damage patterns, clustering conditions can underestimated SSBs by up to 18 % and DSBs can be overestimated by up to 12 % compared to our own implementation. Conclusion: We show that two often underreported simulation parameters have a non-negligible effect on overall DNA damage yields. First more SBs are counted when using energy transfers to the PDG rather than energy deposits. Also, SBs grouped according to different clustering conditions can influence reported SSB and DSB by as much as 20%. Careful handling of these parameters is required when trying to compare DNA damage yields from different authors. Research funding from the governments of Canada and Quebec. PP acknowledges partial support by the CREATE Medical Physics Research Training Network grant of the Natural Sciences and Engineering Research Council (Grant number: 432290)

  4. Breaking Ships in the World-System: An Analysis of Two Ship Breaking Capitals, Alang-Sosiya, India and Chittagong, Bangladesh

    Directory of Open Access Journals (Sweden)

    R. Scott Frey

    2015-08-01

    Full Text Available Centrality in the world-system allows countries to externalize their hazards or environmental harms on others. Core countries, for instance, dump heavy metals and greenhouse gases into the global sinks, and some of the core's hazardous products, production processes and wastes are displaced to the (semi peripheral zones of the world-system. Since few (semi peripheral countries have the ability to assess and manage the risks associated with such hazards, the transfer of core hazards to the (semi periphery has adverse environmental and socio-economic consequences for many of these countries and it has spawned conflict and resistance, as well as a variety of other responses. Most discussions of this risk globalization problem have failed to situate it firmly in the world-system frame emphasizing the process of ecological unequal exchange. Using secondary sources, I begin such a discussion by examining the specific problem of ship breaking (recycling core-based ocean going vessels for steel and other materials at the yards in Alang-Sosiya, India and Chittagong, Bangladesh. Attention centers on the nature and scope of ship breaking in these two locations, major drivers operating in the world-system, adverse consequences, the unequal mix of costs and benefits, and the failure of existing political responses at the domestic and international levels to reduce adequately the adverse consequences of ship breaking.

  5. The Break

    DEFF Research Database (Denmark)

    Strand, Anete Mikkala Camille

    2016-01-01

    The chapter elaborates on how to deal with one of the major challenges facing organizations worldwide; Stress. The Break enacts a quantum approach to meet the challenges by proposing a combination of three different quantum storytelling technologies; protreptic mentoring, walking and material sto...

  6. Breaking Routines

    DEFF Research Database (Denmark)

    Kesting, Peter; Jørgensen, Frances

    2010-01-01

    On some level, innovation begins when the current way of doing things is questioned and alternatives are sought. In cognitive terms, this can be conceptualized as the point at which an agent breaks with existing routine and returns to planning and decision-making. Thus far, however, very little...

  7. Supersymmetry breaking

    Indian Academy of Sciences (India)

    Emilian Dudas

    2009-01-01

    We review the various mechanisms of supersymmetry breaking and its trans-mission to the observable sector. We argue that hybrid models where gauge dominates over gravity mediation, but gravity provides the main contributions to the Higgs sector masses and the neutralino mass, are able to combine the advantages and reduce the disadvantages of the two transmission mechanisms.

  8. Pre-test analysis of an integral effect test facility for thermal-hydraulic similarities of 6 inches coldleg break and DVI injection line break using MARS-1D

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Tae Soon; Choi, Ki Yong; Park, Hyun Sik; Euh, Dong Jin; Baek, Won Pil [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2002-03-01

    A pre-test analysis of a small-break loss-of-coolant accident (SBLOCA, DVI Line break) has been performed for the integral effect test loop of Korea Atomic Energy Research Institute (Korea Atomic Energy Research Institute-ITL), the construction of which will be started soon. The Korea Atomic Energy Research Institute-ITL is a full-height and 1/310 volume-scaled test facility based on the design features of the APR1400 (Korean Next Generation Reactor). This paper briefly introduces the basic design features of the Korea Atomic Energy Research Institute-ITL and presents the results of pre-test analysis for a postulated cold leg SBLOCA and DVI line break. Based on the same control logics and accident scenarios, the similarity between the Korea Atomic Energy Research Institute-ITL and the prototype plant, APR1400, is evaluated by using the MARS code, which is a multi-dimensional best-estimate thermal hydraulic code being developed by Korea Atomic Energy Research Institute. It is found that the Korea Atomic Energy Research Institute-ITL and APR 1400 have similar thermal hydraulic responses against the analyzed SBLOCA and DVI Line break scenario. It is also verified that the volume scaling law, applied to the design of the Korea Atomic Energy Research Institute-ITL, gives a reasonable results to keep a similarity with APR1400. 11 refs., 19 figs., 3 tabs. (Author)

  9. Çokal Dam-break model and flood risk analysis (Çanakkale

    Directory of Open Access Journals (Sweden)

    Hasan Özdemir

    2011-09-01

    Full Text Available The source of the hazard which is the main factor of disasters can be made by naturally or man. These are generally independent sources, but sometimes reason of one hazard such as flood can be both naturally and man-made. Certainly, all examples in our country and the world show that, the fail of constructed structures on the rivers (e.g. dam, embankment produce a very large amount of water and damage more than the normal river floods. In this study, based on cofferdam of Çokal Dam breaching which occurred in 16 November 2007 on the Kavak River (Çanakkale, 1D modeling of probable Çokal Dam break take in the account tectonic properties of the area and analyzing of the flood risk have been done. For these purposes, Digital Elevation Model (DEM gathered contours from 1:25000 scaled topographic maps and GPS points, high and medium resolution satellite images, hydrological soil data gathered from soil maps scaled 1:25000, precipitation and discharge data in 30 years, technical properties of structures on the Kavak River and field measurement have been used as a database. All these data is processed and analyzed using Geographic Information System (GIS, Hec-GeoRAS and HEC-RAS hydraulic models and hydrologic model. Hence, Çokal Dam break modeling based on cofferdam breach modeling reveals that probable flood after the dam-break will affect Evreşe Plain and the people which get livelihood from the plain. General probable lost in agricultural product after probable flood reaches TL 12 million. Thus, as a result of human interventions to the nature will cause great harm to himself again.   

  10. Çokal Dam-break model and flood risk analysis (Çanakkale

    Directory of Open Access Journals (Sweden)

    Hasan Özdemir

    2011-09-01

    Full Text Available The source of the hazard which is the main factor of disasters can be made by naturally or man. These are generally independent sources, but sometimes reason of one hazard such as flood can be both naturally and man-made. Certainly, all examples in our country and the world show that, the fail of constructed structures on the rivers (e.g. dam, embankment produce a very large amount of water and damage more than the normal river floods. In this study, based on cofferdam of Çokal Dam breaching which occurred in 16 November 2007 on the Kavak River (Çanakkale, 1D modeling of probable Çokal Dam break take in the account tectonic properties of the area and analyzing of the flood risk have been done. For these purposes, Digital Elevation Model (DEM gathered contours from 1:25000 scaled topographic maps and GPS points, high and medium resolution satellite images, hydrological soil data gathered from soil maps scaled 1:25000, precipitation and discharge data in 30 years, technical properties of structures on the Kavak River and field measurement have been used as a database. All these data is processed and analyzed using Geographic Information System (GIS, Hec-GeoRAS and HEC-RAS hydraulic models and hydrologic model. Hence, Çokal Dam break modeling based on cofferdam breach modeling reveals that probable flood after the dam-break will affect Evreşe Plain and the people which get livelihood from the plain. General probable lost in agricultural product after probable flood reaches TL 12 million. Thus, as a result of human interventions to the nature will cause great harm to himself again.

  11. Analysis of a small break loss-of-coolant accident of pressurized water reactor by APROS

    Energy Technology Data Exchange (ETDEWEB)

    Al-Falahi, A. [Helsinki Univ. of Technology, Espoo (Finland); Haennine, M. [VTT Energy, Espoo (Finland); Porkholm, K. [IVO International, Ltd., Vantaa (Finland)

    1995-09-01

    The purpose of this paper is to study the capability of APROS (Advanced PROcess Simulator) code to simulate the real plant thermal-hydraulic transient of a Small Break Loss-Of-Coolant Accident (SBLOCA) of Loss-Of-Fluid Test (LOFT) facility. The LOFT is a scaled model of a Pressurized Water Reactor (PWR). This work is a part of a larger validation of the APROS thermal-hydraulic models. The results of SBLOCA transient calculated by APROS showed a reasonable agreement with the measured data.

  12. STRUCTURAL BREAKS, COINTEGRATION, AND CAUSALITY BY VECM ANALYSIS OF CRUDE OIL AND FOOD PRICE

    Directory of Open Access Journals (Sweden)

    Aynur Pala

    2013-01-01

    Full Text Available This papers investigated form of the linkage beetwen crude oil price index and food price index, using Johansen Cointegration test, and Granger Causality by VECM. Empirical results for monthly data from 1990:01 to 2011:08 indicated that evidence for breaks after 2008:08 and 2008:11. We find a clear long-run relationship between these series for the full and sub sample. Cointegration regression coefficient is negative at the 1990:01-2008:08 time period, but adversely positive at the 2008:11-2011:08 time period. This results represent that relation between crude oil and food price chanced.

  13. Theory and Application of Loss of Life Risk Analysis for Dam Break

    Institute of Scientific and Technical Information of China (English)

    孙月峰; 钟登华; 李明超; 李颖

    2010-01-01

    The loss of life risk evaluation model for dam break is built in this paper.By using an improved Monte Carlo method,the overtopping probability induced by concurrent flood and wind is calculated,and the Latin Hypercube Sampling is used to generate random numbers.The Graham method is used to calculate the loss of life resulting from dam failure.With Dongwushi reservoir located at Hebei Province taken as an example,the overtopping probability induced by concurrent flood and wind is calculated as 4.77×10-6.Los...

  14. Breaking the GaN material limits with nanoscale vertical polarisation super junction structures: A simulation analysis

    Science.gov (United States)

    Unni, Vineet; Sankara Narayanan, E. M.

    2017-04-01

    This is the first report on the numerical analysis of the performance of nanoscale vertical superjunction structures based on impurity doping and an innovative approach that utilizes the polarisation properties inherent in III–V nitride semiconductors. Such nanoscale vertical polarisation super junction structures can be realized by employing a combination of epitaxial growth along the non-polar crystallographic axes of Wurtzite GaN and nanolithography-based processing techniques. Detailed numerical simulations clearly highlight the limitations of a doping based approach and the advantages of the proposed solution for breaking the unipolar one-dimensional material limits of GaN by orders of magnitude.

  15. The complex Langevin analysis of spontaneous symmetry breaking induced by complex fermion determinant

    CERN Document Server

    Ito, Yuta

    2016-01-01

    In many interesting physical systems, the determinant which appears from integrating out fermions becomes complex, and its phase plays a crucial role in the determination of the vacuum. An example of this is QCD at low temperature and high density, where various exotic fermion condensates are conjectured to form. Another example is the Euclidean version of the type IIB matrix model for 10d superstring theory, where spontaneous breaking of the SO(10) rotational symmetry down to SO(4) is expected to occur. When one applies the complex Langevin method to these systems, one encounters the singular-drift problem associated with the appearance of nearly zero eigenvalues of the Dirac operator. Here we propose to avoid this problem by deforming the action with a fermion bilinear term. The results for the original system are obtained by extrapolations with respect to the deformation parameter. We demonstrate the power of this approach by applying it to a simple matrix model, in which spontaneous symmetry breaking from...

  16. Analysis of DNA Double-strand Break (DSB) Repair in Mammalian Cells

    Science.gov (United States)

    Seluanov, Andrei; Mao, Zhiyong; Gorbunova, Vera

    2010-01-01

    DNA double-strand breaks are the most dangerous DNA lesions that may lead to massive loss of genetic information and cell death. Cells repair DSBs using two major pathways: nonhomologous end joining (NHEJ) and homologous recombination (HR). Perturbations of NHEJ and HR are often associated with premature aging and tumorigenesis, hence it is important to have a quantitative way of measuring each DSB repair pathway. Our laboratory has developed fluorescent reporter constructs that allow sensitive and quantitative measurement of NHEJ and HR. The constructs are based on an engineered GFP gene containing recognition sites for a rare-cutting I-SceI endonuclease for induction of DSBs. The starting constructs are GFP negative as the GFP gene is inactivated by an additional exon, or by mutations. Successful repair of the I-SceI-induced breaks by NHEJ or HR restores the functional GFP gene. The number of GFP positive cells counted by flow cytometry provides quantitative measure of NHEJ or HR efficiency. PMID:20864925

  17. Analysis of DNA double-strand break (DSB) repair in mammalian cells.

    Science.gov (United States)

    Seluanov, Andrei; Mao, Zhiyong; Gorbunova, Vera

    2010-09-08

    DNA double-strand breaks are the most dangerous DNA lesions that may lead to massive loss of genetic information and cell death. Cells repair DSBs using two major pathways: nonhomologous end joining (NHEJ) and homologous recombination (HR). Perturbations of NHEJ and HR are often associated with premature aging and tumorigenesis, hence it is important to have a quantitative way of measuring each DSB repair pathway. Our laboratory has developed fluorescent reporter constructs that allow sensitive and quantitative measurement of NHEJ and HR. The constructs are based on an engineered GFP gene containing recognition sites for a rare-cutting I-SceI endonuclease for induction of DSBs. The starting constructs are GFP negative as the GFP gene is inactivated by an additional exon, or by mutations. Successful repair of the I-SceI-induced breaks by NHEJ or HR restores the functional GFP gene. The number of GFP positive cells counted by flow cytometry provides quantitative measure of NHEJ or HR efficiency.

  18. Breaking Symmetries

    Directory of Open Access Journals (Sweden)

    Kirstin Peters

    2010-11-01

    Full Text Available A well-known result by Palamidessi tells us that πmix (the π-calculus with mixed choice is more expressive than πsep (its subset with only separate choice. The proof of this result argues with their different expressive power concerning leader election in symmetric networks. Later on, Gorla offered an arguably simpler proof that, instead of leader election in symmetric networks, employed the reducibility of incestual processes (mixed choices that include both enabled senders and receivers for the same channel when running two copies in parallel. In both proofs, the role of breaking (initial symmetries is more or less apparent. In this paper, we shed more light on this role by re-proving the above result - based on a proper formalization of what it means to break symmetries without referring to another layer of the distinguishing problem domain of leader election. Both Palamidessi and Gorla rephrased their results by stating that there is no uniform and reasonable encoding from πmix into πsep. We indicate how the respective proofs can be adapted and exhibit the consequences of varying notions of uniformity and reasonableness. In each case, the ability to break initial symmetries turns out to be essential.

  19. Signal induced Symmetry Breaking in Noise Statistical Properties of Data Analysis

    CERN Document Server

    Perotti, Luca; Bessis, Daniel

    2010-01-01

    From a time series whose data are embedded in heavy noise, we construct an Hilbert space operator (J-operator) whose discrete spectrum represents the signal while the essential spectrum located on the unit circle, is associated with the noise. Furthermore the essential spectrum, in the absence of signal, is built from roots of unity ("clock" distribution). These results are independent of the statistical properties of the noise that can be Gaussian, non-Gaussian, pink or even without second moment (Levy). The presence of the signal has for effect to break the clock angular distribution of the essential spectrum on the unit circle. A discontinuity, proportional to the intensity of the signal, appears in the angular distribution. The sensitivity of this method is definitely better than standard techniques. We build an example that supports our claims.

  20. Analysis of the electron component of EAS at observational level 700 g x cm(-2) with a scale breaking interaction model and gammaisation hypothesis

    Science.gov (United States)

    Procureur, J.; Stamenov, J. N.; Stavrev, P. V.; Ushev, S. Z.

    1985-01-01

    Scale breaking model and gammaisation processes for high energies give a correct description of the longitudinal development of extensive air showers (E.A.S.). From the analysis of phenomenological characteristics of E.A.S. at Tien-Shan experiment, it follows that for energies near 10 to the 6 GeV the secondary particle multiplicity increases with energy faster than is predicted by the accepted scale breaking model.

  1. ROSA-III double-ended break test series for a loss-of-coolant accident in a boiling water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Tasaka, K.; Anoda, Y.; Koizumi, Y.; Kumamaru, H.; Nakamura, H.; Shiba, M.; Suzuki, M.; Yonomoto, T.

    1985-01-01

    The Rig of Safety Assessment (ROSA) III facility is a volumetrically scaled (1/424) boiling water reactor (BWR) system with an electrically heated core designed for integral loss-of-coolant accident (LOCA) and emergency-core-cooling-system (ECCS) tests. Experimental results obtained so far confirm that the severest single failure assumption in ECCS is the high-pressure core spray system failure even in a large-break LOCA in a BWR. The measured peak cladding temperature was well below the present safety criterion of 1473 K, even with the single failure assumption in ECCS, and the effectiveness of ECCS for core cooling during a double-ended-break LOCA has been confirmed. The overall agreement between the results calculated by the RELAP4/MOD6/U4/J3 computer code and the experimental results is good. The similarity between the ROSA-III test and a BWR LOCA has been confirmed through the comparison of calculated results for the ROSA-III facility and a BWR system.

  2. The three-dimension model for the rock-breaking mechanism of disc cutter and analysis of rock-breaking forces

    Institute of Scientific and Technical Information of China (English)

    Zhao-Huang Zhang; Fei Sun

    2012-01-01

    To study the rock deformation with three-dimensional model under rolling forces of disc cutter,by carrying out the circular-grooving test with disc cutter rolling around on the rock,the rock mechanical behavior under rolling disc cutter is studied,the mechanical model of disc cutter rolling around the groove is established,and the theory of single-point and double-angle variables is proposed.Based on this theory,the physics equations and geometric equations of rock mechanical behavior under disc cutters of tunnel boring machine (TBM) are studied,and then the balance equations of interactive forces between disc cutter and rock are established.Accordingly,formulas about normal force,rolling force and side force of a disc cutter are derived,and their validity is studied by tests.Therefore,a new method and theory is proposed to study rock- breaking mechanism of disc cutters.

  3. Conversion of matrixes of parameters and the analysis of circuits after closing and breaking of arbitrary number of branches

    Directory of Open Access Journals (Sweden)

    V. D. Stashuk

    2013-12-01

    Full Text Available The theorem which allows to define the magnitude order of determinant at which value of arbitrary quantity of elements grows infinitely is proved. The method of the analysis of electric circuits after closing and breaking of arbitrary quantity of branches is developed, using only one of matrixes of parameters (conductivities or resistance the initial circuit. Circuit analysis examples after closing of branch are given, using a matrix of conductivities of the initial circuit. Generally when closing arbitrary number of nodal couples theorem application also allows to find potentials of all nodes and currents of all branches, closed branches inclusively. For this purpose it is necessary to the appropriate elements of determinant on which required values are calculated, to add with a due sign of value of y and to pass to a limit, having applied the theorem. If the matrix of Z - parameters of the initial circuit is set, it is possible to receive dual results, using the proved theorem.

  4. RBMK-LOCA-Analyses with the ATHLET-Code

    Energy Technology Data Exchange (ETDEWEB)

    Petry, A. [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH Kurfuerstendamm, Berlin (Germany); Domoradov, A.; Finjakin, A. [Research and Development Institute of Power Engineering, Moscow (Russian Federation)

    1995-09-01

    The scientific technical cooperation between Germany and Russia includes the area of adaptation of several German codes for the Russian-designed RBMK-reactor. One point of this cooperation is the adaptation of the Thermal-Hydraulic code ATHLET (Analyses of the Thermal-Hydraulics of LEaks and Transients), for RBMK-specific safety problems. This paper contains a short description of a RBMK-1000 reactor circuit. Furthermore, the main features of the thermal-hydraulic code ATHLET are presented. The main assumptions for the ATHLET-RBMK model are discussed. As an example for the application, the results of test calculations concerning a guillotine type rupture of a distribution group header are presented and discussed, and the general analysis conditions are described. A comparison with corresponding RELAP-calculations is given. This paper gives an overview on some problems posed and experience by application of Western best-estimate codes for RBMK-calculations.

  5. Post-Test Analysis of 11% Break at PSB-VVER Experimental Facility using Cathare 2 Code

    Science.gov (United States)

    Sabotinov, Luben; Chevrier, Patrick

    The best estimate French thermal-hydraulic computer code CATHARE 2 Version 2.5_1 was used for post-test analysis of the experiment “11% upper plenum break”, conducted at the large-scale test facility PSB-VVER in Russia. The PSB rig is 1:300 scaled model of VVER-1000 NPP. A computer model has been developed for CATHARE 2 V2.5_1, taking into account all important components of the PSB facility: reactor model (lower plenum, core, bypass, upper plenum, downcomer), 4 separated loops, pressurizer, horizontal multitube steam generators, break section. The secondary side is represented by recirculation model. A large number of sensitivity calculations has been performed regarding break modeling, reactor pressure vessel modeling, counter current flow modeling, hydraulic losses, heat losses. The comparison between calculated and experimental results shows good prediction of the basic thermal-hydraulic phenomena and parameters such as pressures, temperatures, void fractions, loop seal clearance, etc. The experimental and calculation results are very sensitive regarding the fuel cladding temperature, which show a periodical nature. With the applied CATHARE 1D modeling, the global thermal-hydraulic parameters and the core heat up have been reasonably predicted.

  6. Viscosimetric analysis of the occurrence and repair of DNA single-strand breaks in irradiated animal tissues.

    Science.gov (United States)

    Ryabchenko, N I; Ivannik, B P; Proskuryakov SYa

    1982-04-01

    The yields of immediate DNA single-strand breaks in normal tumour tissues of irradiated animals were measured by a viscosimetric method of determination of high-polymer single-strand DNA molecular weight in alkaline nuclear lysates. It has been shown that in irradiated thymus, bone marrow leukocytes, Ehrlich ascitic carcinoma and Zaidel hepatoma cells (first group by tissues) in vivo the yields of DNA single-strand breaks were characterized by 80 to 130 eV per break. In in vivo irradiated liver, lymph node, spleen, and sarcoma 180 cells (second group of tissues) the yields of DNA single-strand breaks have been characterized by 30 to 40 eV per break. DNA single-strand breaks of the first group of tissues have rejoined 1 hour after the irradiation in vivo; DNA single-strand breaks of the second group have not done so.

  7. Viscosimetric analysis of the occurrence and repair of DNA single-strand breaks in irradiated animal tissues

    Energy Technology Data Exchange (ETDEWEB)

    Ryabchenko, N.I.; Ivannik, B.P.; Proskuryakov, S.Ya. (Akademiya Meditsinskikh Nauk SSSR, Obninsk. Nauchno-Issledovatel' skij Inst. Meditsinskoj Radiologii)

    1982-04-01

    The yields of immediate DNA single-strand breaks in normal tumour tissues of ..gamma..-irradiated animals were measured by a viscosimetric method of determination of high-polymer single-strand DNA molecular weight in alkaline nuclear lysates. It has been shown that in irradiated thymus, bone marrow leukocytes, Ehrlich ascitic carcinoma and Zaidel hepatoma cells (first group of tissues) in vivo the yields of DNA single-strand breaks were characterized by 80 to 130 eV per break. In in vivo irradiated liver, lymph node, spleen, and sarcoma 180 cells (second group of tissues) the yields of DNA single-strand breaks have been characterized by 30 to 40 eV per break. DNA single-strand breaks of the first group of tissues have rejoined 1 hour after the irradiation in vivo; DNA single-strand breaks of the second group have not done so.

  8. Theory and Application of Loss of Life Risk Analysis for Dam Break

    Institute of Scientific and Technical Information of China (English)

    SUN Yuefeng; ZHONG Denghua; LI Mingchao; LI Ying

    2010-01-01

    The loss of life risk evaluation model for dam break is built in this paper.By using an improved Monte Carlo method,the overtopping probability induced by concurrent flood and wind is calculated,and the Latin Hypercube Sampling is used to generate random numbers.The Graham method is used to calculate the loss of life resulting from dam failure.With Dongwushi reservoir located at Hebei Province taken as an example,the overtopping probability induced by concurrent flood and wind is calculated as 4.77×10 6.Loss of life is 24 220 when the warning time is0.25-1 h and flood severity understanding is vague,which indicates that the risk is intolerable.The losses of life under three other conditions are tolerable: warning time 0.25-1 h,and precise flood severity understanding; warning time more than 1 h,and vague flood severity understanding; warning time more than 1 h,and precise flood severity understanding.

  9. Kinetic analysis of Yersinia pestis DNA adenine methyltransferase activity using a hemimethylated molecular break light oligonucleotide.

    Directory of Open Access Journals (Sweden)

    Robert J Wood

    Full Text Available BACKGROUND: DNA adenine methylation plays an important role in several critical bacterial processes including mismatch repair, the timing of DNA replication and the transcriptional control of gene expression. The dependence of bacterial virulence on DNA adenine methyltransferase (Dam has led to the proposal that selective Dam inhibitors might function as broad spectrum antibiotics. METHODOLOGY/PRINCIPAL FINDINGS: Herein we report the expression and purification of Yersinia pestis Dam and the development of a continuous fluorescence based assay for DNA adenine methyltransferase activity that is suitable for determining the kinetic parameters of the enzyme and for high throughput screening against potential Dam inhibitors. The assay utilised a hemimethylated break light oligonucleotide substrate containing a GATC methylation site. When this substrate was fully methylated by Dam, it became a substrate for the restriction enzyme DpnI, resulting in separation of fluorophore (fluorescein and quencher (dabcyl and therefore an increase in fluorescence. The assays were monitored in real time using a fluorescence microplate reader in 96 well format and were used for the kinetic characterisation of Yersinia pestis Dam, its substrates and the known Dam inhibitor, S-adenosylhomocysteine. The assay has been validated for high throughput screening, giving a Z-factor of 0.71+/-0.07 indicating that it is a sensitive assay for the identification of inhibitors. CONCLUSIONS/SIGNIFICANCE: The assay is therefore suitable for high throughput screening for inhibitors of DNA adenine methyltransferases and the kinetic characterisation of the inhibition.

  10. Analysis of DNA double-strand break repair pathways in mice

    Energy Technology Data Exchange (ETDEWEB)

    Brugmans, Linda [Department of Cell Biology and Genetics, Erasmus MC, Dr. Molewaterplein 50, PO Box 1738, Rotterdam 3015GE (Netherlands); Kanaar, Roland [Department of Cell Biology and Genetics, Erasmus MC, Dr. Molewaterplein 50, PO Box 1738, Rotterdam 3015GE (Netherlands); Department of Radiation Oncology, Erasmus MC, PO Box 1738, 3000 DR Rotterdam (Netherlands); Essers, Jeroen [Department of Cell Biology and Genetics, Erasmus MC, Dr. Molewaterplein 50, PO Box 1738, Rotterdam 3015GE (Netherlands) and Department of Radiation Oncology, Erasmus MC, PO Box 1738, 3000 DR Rotterdam (Netherlands)]. E-mail: j.essers@erasmusmc.nl

    2007-01-03

    During the last years significant new insights have been gained into the mechanism and biological relevance of DNA double-strand break (DSB) repair in relation to genome stability. DSBs are a highly toxic DNA lesion, because they can lead to chromosome fragmentation, loss and translocations, eventually resulting in cancer. DSBs can be induced by cellular processes such as V(D)J recombination or DNA replication. They can also be introduced by exogenous agents DNA damaging agents such as ionizing radiation or mitomycin C. During evolution several pathways have evolved for the repair of these DSBs. The most important DSB repair mechanisms in mammalian cells are nonhomologous end-joining and homologous recombination. By using an undamaged repair template, homologous recombination ensures accurate DSB repair, whereas the untemplated nonhomologous end-joining pathway does not. Although both pathways are active in mammals, the relative contribution of the two repair pathways to genome stability differs in the different cell types. Given the potential differences in repair fidelity, it is of interest to determine the relative contribution of homologous recombination and nonhomologous end-joining to DSB repair. In this review, we focus on the biological relevance of DSB repair in mammalian cells and the potential overlap between nonhomologous end-joining and homologous recombination in different tissues.

  11. Breaking Symmetries

    CERN Document Server

    Peters, Kirstin

    2010-01-01

    A well-known result by Palamidessi tells us that {\\pi}mix (the {\\pi}-calculus with mixed choice) is more expressive than {\\pi}sep (its subset with only separate choice). The proof of this result argues with their different expressive power concerning leader election in symmetric networks. Later on, Gorla of- fered an arguably simpler proof that, instead of leader election in symmetric networks, employed the reducibility of "incestual" processes (mixed choices that include both enabled senders and receivers for the same channel) when running two copies in parallel. In both proofs, the role of breaking (ini- tial) symmetries is more or less apparent. In this paper, we shed more light on this role by re-proving the above result-based on a proper formalization of what it means to break symmetries-without referring to another layer of the distinguishing problem domain of leader election. Both Palamidessi and Gorla rephrased their results by stating that there is no uniform and reason- able encoding from {\\pi}mix i...

  12. Breaking Symmetries

    CERN Document Server

    Peters, Kirstin; 10.4204/EPTCS.41.10

    2010-01-01

    A well-known result by Palamidessi tells us that \\pimix (the \\pi-calculus with mixed choice) is more expressive than \\pisep (its subset with only separate choice). The proof of this result argues with their different expressive power concerning leader election in symmetric networks. Later on, Gorla offered an arguably simpler proof that, instead of leader election in symmetric networks, employed the reducibility of incestual processes (mixed choices that include both enabled senders and receivers for the same channel) when running two copies in parallel. In both proofs, the role of breaking (initial) symmetries is more or less apparent. In this paper, we shed more light on this role by re-proving the above result - based on a proper formalization of what it means to break symmetries without referring to another layer of the distinguishing problem domain of leader election. Both Palamidessi and Gorla rephrased their results by stating that there is no uniform and reasonable encoding from \\pimix into \\pisep. We...

  13. Symmetry-breaking analysis for the general Helmholtz-Duffing oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Cao Hongjun [Department of Mathematics, School of Science, Beijing Jiaotong University, Beijing 100044 (China) and Nonlinear Dynamics and Chaos Group, Departamento de Ciencias de la Naturaleza y Fisica Aplicada, Universidad Rey Juan Carlos, Tulipan s/n, 28933 Mostoles, Madrid (Spain)]. E-mail: hjcao@center.njtu.edu.cn; Seoane, Jesus M. [Nonlinear Dynamics and Chaos Group, Departamento de Ciencias de la Naturaleza y Fisica Aplicada, Universidad Rey Juan Carlos, Tulipan s/n, 28933 Mostoles, Madrid (Spain); Sanjuan, Miguel A.F. [Nonlinear Dynamics and Chaos Group, Departamento de Ciencias de la Naturaleza y Fisica Aplicada, Universidad Rey Juan Carlos, Tulipan s/n, 28933 Mostoles, Madrid (Spain)

    2007-10-15

    The symmetry breaking phenomenon for a general Helmholtz-Duffing oscillator as a function of a symmetric parameter in the nonlinear force is investigated. Different values of this parameter convert the general oscillator into either the Helmholtz or the Duffing oscillator. Due to the variation of the symmetric parameter, the phase space patterns of the unperturbed Helmholtz-Duffing oscillator will cause a huge difference between the left-hand homoclinic orbit and the right-hand one. In particular, the area of the left-hand homoclinic orbits is a strictly monotonously decreasing function, while the area of the right-hand homoclinic orbit varies only in a very small range. There exist distinct local supercritical and subcritical saddle-node bifurcations at two different centers. The left-hand and the right-hand existing regions of the harmonic solutions of the Helmholtz-Duffing oscillator created by the left-hand and the right-hand saddle-node bifurcation curves will lead to different transition in the amplitude-frequency plane. There exists also a critical frequency which has the effect that the left-hand homoclinic bifurcation value is equal to the right-hand homoclinic bifurcation value. And, if the amplitude coefficient of the Helmholtz-Duffing oscillator is used as the control parameter, and it is larger than the same left-hand and right-hand homoclinic bifurcation, then the global stability of the system will be destroyed at a lowest cost. Besides this critical frequency, the left-hand and the right-hand homoclinic bifurcations are not only unequal, but also their effects for the system's stability are different. Among them, the effect resulting from the small homoclinic bifurcation for the system's stability is local and negligible, while the effect from the large homoclinic bifurcation is global but this is accomplished at a quite larger cost.

  14. Timing analysis of PWR fuel pin failures

    Energy Technology Data Exchange (ETDEWEB)

    Jones, K.R.; Wade, N.L.; Katsma, K.R.; Siefken, L.J. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Straka, M. (Halliburton NUS, Idaho Falls, ID (United States))

    1992-09-01

    Research has been conducted to develop and demonstrate a methodology for calculation of the time interval between receipt of the containment isolation signals and the first fuel pin failure for loss-of-coolant accidents (LOCAs). Demonstration calculations were performed for a Babcock and Wilcox (B W) design (Oconee) and a Westinghouse (W) four-loop design (Seabrook). Sensitivity studies were performed to assess the impacts of fuel pin bumup, axial peaking factor, break size, emergency core cooling system availability, and main coolant pump trip on these times. The analysis was performed using the following codes: FRAPCON-2, for the calculation of steady-state fuel behavior; SCDAP/RELAP5/MOD3 and TRACPF1/MOD1, for the calculation of the transient thermal-hydraulic conditions in the reactor system; and FRAP-T6, for the calculation of transient fuel behavior. In addition to the calculation of fuel pin failure timing, this analysis provides a comparison of the predicted results of SCDAP/RELAP5/MOD3 and TRAC-PFL/MOD1 for large-break LOCA analysis. Using SCDAP/RELAP5/MOD3 thermal-hydraulic data, the shortest time intervals calculated between initiation of containment isolation and fuel pin failure are 10.4 seconds and 19.1 seconds for the B W and W plants, respectively. Using data generated by TRAC-PF1/MOD1, the shortest intervals are 10.3 seconds and 29.1 seconds for the B W and W plants, respectively. These intervals are for a double-ended, offset-shear, cold leg break, using the technical specification maximum peaking factor and applied to fuel with maximum design bumup. Using peaking factors commensurate widi actual bumups would result in longer intervals for both reactor designs. This document also contains appendices A through J of this report.

  15. The Break

    DEFF Research Database (Denmark)

    Strand, Anete Mikkala Camille; Larsen, Jens

    2015-01-01

    are elaborated as founding differences for the leadership actions to come aka for the engagement in practices of becoming. Material storytelling story modes are posed as material-discursive attempts at rebalancing present hegemonies of mind/body, nature/culture, matter/meaning, etc. with relation to the posed...... and euro each year. The paper tries to explore new ways to deal with these challenges through a quantum approach to storytelling where the enactment of core values, bodies, spaces and artifacts positions managers and CEO’s from major Scandinavian organizations in sites where they can re-evaluate their life...... stones on a table in an office of a municipality in Denmark. Silence….. Rebuilding rooms for taking breaks with the inclusion of different activities such as a game of soccer or a hike seems to provide the tools to rework these imbalances or enslaving patterns. Break……. The attempt at meeting...

  16. Evaluation of the simultaneous action of earthquake, LOCA and SRV on Mark-III containment and drywell structures. [Safety Relief Valve

    Energy Technology Data Exchange (ETDEWEB)

    Philippacopoulos, A.J.; Reich, M.

    1981-01-01

    The containment and drywell structures of a generic Mark-III nuclear power facility are investigated with respect to their structural response when subjected to various load combinations that may occur during their operational lifetime. Both structures are idealized with three-dimensional finite element models. In addition a lumped-mass cantilever beam representation of the containment and drywell structures is developed and used for the soil-structure interaction analysis. The types of dynamic events considered include earthquakes, loss-of-coolant-accidents (LOCA) and those generated by safety/relief valve actuations. The evaluation of the combined actions of these dynamic events is first performed by using combination methods such as Absolute Sum (ABS) and Square-Root-of-the-Sum-of-the-Squares (SRSS). A Monte Carlo simulation procedure is subsequently used for probabilistic evaluation of the combinations.

  17. Analysis on Dynamic Dielectric Recovery and Statistical Property of Vacuum Circuit-Breakers with Multi-Breaks

    Institute of Scientific and Technical Information of China (English)

    廖敏夫; 段雄英; 邹积岩

    2004-01-01

    Based on the dynamic dielectric recovery process in the vacuum gaps in series, investigations were made on post-arc insulation state in double and multi-breaks operation in high voltage power system. From the research on the breakdown weak points in high voltage vacuum gaps, their turnout and distribution, some theoretic work were made to set up the models for describing the statistical property of multi-breaks vacuum circuit-breakers' breakdown and post-arc re-strike, which can be used for explaining the mechanism of the improvement in the breaking capacity of multi-breaks units compared with that of single-break ones which have the same equivalent gap length. The advantages of vacuum breakers with multi-breaks are proposed.

  18. Analysis of in vivo and in vitro DNA strand breaks from trihalomethane exposure

    Directory of Open Access Journals (Sweden)

    DeAngelo Anthony

    2004-01-01

    Full Text Available Abstract Background Epidemiological studies have linked the consumption of chlorinated surface waters to an increased risk of two major causes of human mortality, colorectal and bladder cancer. Trihalomethanes (THMs are by-products formed when chlorine is used to disinfect drinking water. The purpose of this study was to examine the ability of the THMs, trichloromethane (TCM, bromodichloromethane (BDCM, dibromochloromethane (DBCM, and tribromomethane (TBM, to induce DNA strand breaks (SB in (1 CCRF-CEM human lymphoblastic leukemia cells, (2 primary rat hepatocytes (PRH exposed in vitro, and (3 rats exposed by gavage or drinking water. Methods DNA SB were measured by the DNA alkaline unwinding assay (DAUA. CCRF-CEM cells were exposed to individual THMs for 2 hr. Half of the cells were immediately analyzed for DNA SB and half were transferred into fresh culture medium and incubated for an additional 22 hr before testing for DNA SB. PRH were exposed to individual THMs for 4 hr then assayed for DNA SB. F344/N rats were exposed to individual THMs for 4 hr, 2 weeks, and to BDCM for 5 wk then tested for DNA SB. Results CCRF-CEM cells exposed to 5- or 10-mM brominated THMs for 2 hr produced DNA SB. The order of activity was TBM>DBCM>BDCM; TCM was inactive. Following a 22-hr recovery period, all groups had fewer SB except 10-mM DBCM and 1-mM TBM. CCRF-CEM cells were found to be positive for the GSTT1-1 gene, however no activity was detected. No DNA SB, unassociated with cytotoxicity, were observed in PRH or F344/N rats exposed to individual THMs. Conclusion CCRF-CEM cells exposed to the brominated THMs at 5 or 10 mM for 2 hr showed a significant increase in DNA SB when compared to control cells. Additionally, CCRF-CEM cells exposed to DBCM and TBM appeared to have compromised DNA repair capacity as demonstrated by an increased amount of DNA SB at 22 hr following exposure. CCRF-CEM cells were found to be positive for the GSTT1-1 gene, however no activity

  19. Política habitacional no Brasil e Programa de Locação Social paulistano

    Directory of Open Access Journals (Sweden)

    Camila D'Ottaviano

    Full Text Available O artigo apresenta uma breve analise da política habitacional brasileira, tendo como estudo de caso específico o Programa de Locação Social instituído no município de São Paulo em 2002. O Programa de Locação Social paulistano é o principal programa habitacional alicerçado na locação implantado no Brasil recentemente. Criado pela Resolução nº 23 do Conselho do Fundo Municipal de Habitação, visava atender à demanda das famílias com renda de até três salários mínimos, excluídas até então dos programas existentes de financiamento habitacional. Após 10 anos de sua implantação, as principais limitações apontadas são a falta de acompanhamento social da demanda atendida e a falta de acompanhamento na gestão das áreas condominiais. Outra questão ainda não resolvida, no âmbito do programa de locação social, é o tempo máximo de permanência das famílias nos empreendimentos, bem como o atendimento a uma demanda muito superior à capacidade do Programa.

  20. Finite Element Analysis of PVC window profile &aluminium window profile with and without thermal break

    Directory of Open Access Journals (Sweden)

    ENG. Mohammad Buhemdi

    2016-05-01

    Full Text Available Examine a thermal analysis .Numerous analogies exist between thermal and structuralanalysis for PVC window profile &aluminium window profile with and without thermalbreak ,Finite Element Analysis, commonly called FEA, is a method of numerical analysis. FEA isused for solving problems in many engineering disciplines such as machine design,acoustics, electromagnetism, soil mechanics, fluid dynamics, and many others. Inmathematical terms, FEA is a numerical technique used for solving field problemsdescribed by a set of partial differential equations. In mechanical engineering, FEA iswidely used for solving structural, vibration, and thermal problems. However, FEA is notthe only available tool of numerical analysis. Other numerical methods include the FiniteDifference Method, the Boundary Element Method, and the Finite Volumes Method tomention just a few. However, due to its versatility and numerical efficiency, FEA has cometo dominate the engineering analysis software market, while other methods have beenrelegated to niche applications. When implemented into modern commercial software,both FEA theory and numerical problem formulation become completely transparent tousers.

  1. Validation of updated RANNS with effect of oxygen-dissolved metallic Zircaloy-4 under LOCA quench condition

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hsingtzu; Udagawa, Yutaka; Narukawa, Takafumi; Amaya, Masaki, E-mail: amaya.masaki@jaea.go.jp

    2016-04-15

    Highlights: • Equations about the impact of the oxygen-dissolved Zircaloy-4 metallic layer which are newly added to RANNS code are described. • Validation of RANNS code using LOCA quench experimental data is presented. • The impact of the oxygen-dissolved metallic layer and the oxide layer formed on the surface of cladding on its axial load is discussed. - Abstract: Loss-of-Coolant-Accident (LOCA) is a design basis accident considered in LWR safety analyses, and LOCA simulation technique can be used to gain a better understanding of local cladding behaviors. This paper first summarizes equations regarding the oxygen-dissolved metallic Zircaloy-4 which have been implemented into the updated RANNS code. It is then validated using experimental data. The oxidation temperature is about 1473 K, the oxidation time is about 182.5 s and the quench temperature is about 973 K. The difference between the measured axial load and the RANNS computation as the cladding surface temperature reaches about 373 K is about 18.7%. In addition, the updated RANNS code is used to examine the influence of the oxygen absorbed into cladding on its axial load under LOCA quench conditions with oxidation time up to 674 s. The results suggest that the contributions of both the oxygen-dissolved metallic layer and the oxide layer to the axial load increase with oxidation time. The former corresponds to about a tenth of the computed axial load. These findings are considered useful for improving the accuracy of the analyses of the fuel rod behaviors during LOCA conditions.

  2. [Clarification of a break-in theft crime by multiplex PCR analysis of cigarette butts].

    Science.gov (United States)

    Hochmeister, M; Haberl, J; Borer, V; Rudin, O; Dirnhofer, R

    1995-01-01

    This paper describes the first use of multiplex PCR amplification kits for the analysis of DNA extracted from cigarette butts in a criminal case. Two suspects could be excluded as potential contributors to the samples, whereas the multi locus PCR-based DNa profile derived from the cigarette butts was consistent with a DNA profile derived from a third suspect. For identity testing in criminal cases where cigarette butts are involved, commercially available PCR amplification kits provide currently the most powerful tool. Furthermore this PCR-based analysis can be implemented into most application orientated laboratories.

  3. APT Blanket System Loss-of-Coolant Analysis Based on Initial Conceptual Design - Case 2: External HR Break HR Break at Pump Outlet with Pump Trip

    Energy Technology Data Exchange (ETDEWEB)

    Hamm, L.L.

    1998-10-07

    This report is one of a series of reports that document normal operation and accident simulations for the Accelerator Production of Tritium (APT) blanket heat removal system. These simulations were performed for the Preliminary Safety Analysis Report.

  4. Evolutionary analysis of tomato Sw-5 resistance-breaking isolates of Tomato spotted wilt virus.

    Science.gov (United States)

    López, Carmelo; Aramburu, José; Galipienso, Luis; Soler, Salvador; Nuez, Fernando; Rubio, Luis

    2011-01-01

    Tomato spotted wilt virus (TSWV) causes severe economic losses in many crops worldwide and often overcomes resistant cultivars used for disease control. Comparison of nucleotide and amino acid sequences suggested that tomato resistance conferred by the gene Sw-5 can be overcome by the amino acid substitution C to Y at position 118 (C118Y) or T120N in the TSWV movement protein, NSm. Phylogenetic analysis revealed that substitution C118Y has occurred independently three times in the studied isolates by convergent evolution, whereas the substitution T120N was a unique event. Analysis of rates of non-synonymous and synonymous changes at individual codons showed that substitution C118Y was positively selected.

  5. Analysis of seismic disaster failure mechanism and dam-break simulation of high arch dam

    Science.gov (United States)

    Zhang, Jingkui; Zhang, Liaojun

    2014-06-01

    Based on a Chinese national high arch dam located in a meizoseismal region, a nonlinear numerical analysis model of the damage and failure process of a dam-foundation system is established by employing a 3-D deformable distinct element code (3DEC) and its re-development functions. The proposed analysis model considers the dam-foundation-reservoir coupling effect, influence of nonlinear contact in the opening and closing of the dam seam surface and abutment rock joints during strong earthquakes, and radiation damping of far field energy dissipation according to the actual workability state of an arch dam. A safety assessment method and safety evaluation criteria is developed to better understand the arch dam system disaster process from local damage to ultimate failure. The dynamic characteristics, disaster mechanism, limit bearing capacity and the entire failure process of a high arch dam under a strong earthquake are then analyzed. Further, the seismic safety of the arch dam is evaluated according to the proposed evaluation criteria and safety assessment method. As a result, some useful conclusions are obtained for some aspects of the disaster mechanism and failure process of an arch dam. The analysis method and conclusions may be useful in engineering practice.

  6. PIE of the second fuel rod from the LOCA experiment (IFA-650.2)

    Energy Technology Data Exchange (ETDEWEB)

    Oberlaender, B.C.; Jenssen, H.K.; Espeland, M.; Solum, N.O.

    2005-07-01

    The LOCA experiment on the second rod (IFA-650.2) a fresh, low-tin Zr-4, pressurised PWR rod was carried out in May 2004. The main objective was to produce ballooning, to determine the time to burst and to assess the material oxidation and hydriding kinetics. The rod pressure at hot conditions and peak PCT were 70 bar and 1050 C, respectively. To document the effect of the LOCA testing on the cladding, rod 2 was subjected in PIE to visual inspection, profilometry and metallography. On visual inspection the clad shows a typical balloon. In the region of max ballooning the clad shows a 35 mm long, < 20 mm burst opening. In the balloon region the outer clad diameter increased by <35% and locally the wall thickness reduction is >55%. The entire rod is covered with a black oxide layer. Below and above the split opening the continuous oxide layer was 40 to 50mum both on water and fuel side of the clad. At the locations of the upper and lower cladding thermocouples the oxide thickness was in the range 24-27 mum. Widmanstaetten structure is seen in the bulk of the clad and confirms the high temperature experienced. A some 40mum wide, hard and brittle zone with oxygen rich globular alpha-grains is found both at the outer and the inner edge of the clad in the balloon region. The zone is widest near the axial split (crack). In the clad few, arbitrary oriented hydride platelets are observed in the balloon area. (Author)

  7. Analysis of boundary point (break point) in Linear Delay Model for nanoscale VLSI standard cell library characterization at PVT corners

    CERN Document Server

    Agarwal, Gaurav Kumar

    2014-01-01

    In VLSI chip design flow, Static Timing Analysis (STA) is used for fast and accurate analysis of data-path delay. This process is fast because delay is picked from Look Up Tables (LUT) rather than conventional SPICE simulations. But accuracy of this method depends upon the underlying delay model with which LUT was characterized. Non Linear Delay Model (NLDM) based LUTs are quite common in industries. These LUT requires huge amount to time during characterization because of huge number of SPICE simulations done at arbitrary points. To improve this people proposed various other delay models like alpha-power and piecewise linear delay models. Bulusu et al proposed Linear Delay Model(LDM) which reduces LUT generation time to 50 percent. LDM divides delay curve w.r.t input rise time(trin) into two different region one is linear and other is non-linear. This boundary point between linear and non- linear region was called break point (trb). Linear region will be done if we simulate at only two points. This advantage...

  8. Microstructure and mechanical properties of Zircaloy-4 cladding hydrogenated at temperatures typical for loss-of-coolant accident (LOCA) conditions

    Energy Technology Data Exchange (ETDEWEB)

    Pshenichnikov, Anton, E-mail: anton.pshenichnikov@kit.edu; Stuckert, Juri; Walter, Mario

    2015-03-15

    Highlights: • Change of Zircaloy-4 cladding microstructure during hydriding. • Cracks origination during hydrogenation at constant temperature. • Microhardness growth from 195 to 320 HV for hydrogen contents 0–10,000 wppm H. • XRD detection of unequal change of two lattice parameters. • Significant residual ductility reduction at room temperature above 700 wppm hydrogen. - Abstract: The series of single rod tests was performed at KIT in framework of the new QUENCH-LOCA programme to investigate the properties of Zircaloy-4 claddings hydrogenated at temperatures of 900, 1000, 1100, and 1200 K to hydrogen contents between 600 and 10,000 wppm H. The impact of simultaneous annealing, phase transformation and hydriding processes on the material properties was investigated. Changes in microhardness revealed the distinct transition from annealing softening to hydrogen hardening. The intermediate stages of structure transformation during hydrogenation phase were registered. The X-ray diffractometry (XRD) analysis was applied to observe the existing phases in the tested samples including possibly precipitated hydrides as well as change in the lattice parameters a and c. The presence of γ- and δ-hydrides was clearly indicated by this method; however the dimensions of hydrides correspond rather to the nano-scale and could not be observed by optical microscopy. The evolution of XRD peak intensities and peak shift was analysed to estimate the texture change and concentration of dissolved hydrogen correspondingly. Tensile test examination of tube samples at room temperatures showed significant reduction of their residual ductility already at 700 wppm H.

  9. Failure analysis of polycrystalline diamond compact cutters for breaking rock by bending waves theory

    Institute of Scientific and Technical Information of China (English)

    GONG Sheng-wu; ZHAO Fu-jun

    2008-01-01

    The breakage mechanism of the polycrystalline diamond compact(PDC) cutters was analyzed by the energy theory of bending waves. The cutting tests of granite block were conducted on a multifunctional testing device by using the cutter at three kinds of negative fore angles of 30°, 45° and 60°. The results show that, when the edge of the PDC layer is broken, the layer of tungsten cobalt is broken a little under the angle of 30°, while the layer of tungsten cobalt is broken continuously under the angle of60°, their maximum depths are about 2 and 7 mm respectively in the two cases. The eccentric distance mainly depends on the negative fore angle of the cutter. When the cutter thrusts into the rock under an attack angle of 60°, the energy of bending waves reaches the maximum since the eccentric distance is the maximum. So the damage of cutter is the most serious. This test result is consistent with the conclusion of theoretical analysis well. The eccentric distance from the axial line of cutter to the point of action between the rock and cutter has great effect on the breakage of the cutter. Thus during the process of cutting, the eccentric distance should be reduced to improve the service life of PDC cutters.

  10. Breaking the Carnot limit without violating the second law: A thermodynamic analysis of off-resonant quantum light generation

    Science.gov (United States)

    Boukobza, E.; Ritsch, H.

    2013-06-01

    The Carnot limit, formulated in 1824, represents the maximal efficiency of a classical heat engine. In this work we present a thermodynamical analysis of a light amplifier based on a three-level atom coupled off-resonantly to a single quantized cavity mode and to two heat reservoirs with positive temperatures. Based on standard work and heat flow equilibrium, we show that for a cavity blue-detuned with respect to the atomic resonance, the system can surpass the Carnot limit. Nevertheless, the second law of thermodynamics is still obeyed, as the total entropy always increases. By analyzing a semiclassical version of the model, we derive a formula for the critical frequency for which the Carnot limit is broken and a formula for the amplifier efficiency which agrees with its quantum counterpart. In the semiclassical regime, however, the second law is not satisfied and hence it does not offer a physically acceptable description of the system. Finally, we show that breaking the Carnot limit occurs also in a blue-detuned quantum amplifier with output coupling, which represents a realistic model of a laser or maser.

  11. Perspectives on the application of order-statistics in best-estimate plus uncertainty nuclear safety analysis

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Robert P., E-mail: smsrpm@owt.co [AREVA NP, Inc., 3315 Old Forest Road, Lynchburg, VA (United States); Nutt, William T. [Nuclear Safety Analysis Services, 500 Aloha Street 403, Seattle, WA 98109 (United States)

    2011-01-15

    Research highlights: Historical recitation on application of order-statistics models to nuclear power plant thermal-hydraulics safety analysis. Interpretation of regulatory language regarding 10 CFR 50.46 reference to a 'high level of probability'. Derivation and explanation of order-statistics-based evaluation methodologies considering multi-variate acceptance criteria. Summary of order-statistics models and recommendations to the nuclear power plant thermal-hydraulics safety analysis community. - Abstract: The application of order-statistics in best-estimate plus uncertainty nuclear safety analysis has received a considerable amount of attention from methodology practitioners, regulators, and academia. At the root of the debate are two questions: (1) what is an appropriate quantitative interpretation of 'high level of probability' in regulatory language appearing in the LOCA rule, 10 CFR 50.46 and (2) how best to mathematically characterize the multi-variate case. An original derivation is offered to provide a quantitative basis for 'high level of probability.' At root of the second question is whether one should recognize a probability statement based on the tolerance region method of Wald and Guba, et al., for multi-variate problems, one explicitly based on the regulatory limits, best articulated in the Wallis-Nutt 'Testing Method', or something else entirely. This paper reviews the origins of the different positions, key assumptions, limitations, and relationship to addressing acceptance criteria. It presents a mathematical interpretation of the regulatory language, including a complete derivation of uni-variate order-statistics (as credited in AREVA's Realistic Large Break LOCA methodology) and extension to multi-variate situations. Lastly, it provides recommendations for LOCA applications, endorsing the 'Testing Method' and addressing acceptance methods allowing for limited sample failures.

  12. KSTAR Severe Accident Analysis using MELCOR : Ex-vessel Coolant Pipe Break with Failure of Fusion Power Termination System

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Sung Bo; Bang, In Cheol [UNIST, Ulsan (Korea, Republic of)

    2015-10-15

    To investigate the consequence of severe accidents in fusion reactor, a number of thermal hydraulics simulation codes were used (ECART, INTRA, ATHENA/RELAP and so on). MELCOR is chosen as the thermal hydraulics code to simulate the consequence of radioactive material release from accident in preliminary safety report. Capability of the simulation code for fusion reactor severe accident analysis is ability to simulate the hydraulic system in ITER and the transport phenomenon of radionuclides. MELCOR is a fully integrated code that models the accidents in Light Water Reactor (LWR). There are three kinds of radioactive materials in fusion reactor; tritium (or Tiritiated water: HTO), activation products (AP) of divertor or first-wall and activated corrosion products(ACP). In generic Site Safety Report (GSSR), the release guidelines for tritium and activation products are listed for normal operation, incidents, and accidents. And this guidelines presented in Table 1. Not only ITER, the KSTAR (Korea Superconducting Tokamak Advanced Research) is also developing fusion research reactor. The scale of facility is smaller than ITER but this small scale of facility offers the experimental flexibility to develop fusion technology. The major differences between KSTAR and ITER systems are presented in Table 2. Fusion source difference between KSTAR and ITER is D-D fusion reaction (Deuterium-Deuterium fusion reaction) and D-T fusion reaction (Deuterium-Tritium fusion reaction). This D-D fusion makes one tritium by 50 percent chance. The radioactivity of tritium is small to consider compared to radioactive materials in nuclear fission reactor. This reaction is presented in equation (1) In the present work, conservatively estimated tritium inventory amount in KSTAR is used with one of the most severe accident in ITER; Ex-vessel pipe break with Fusion Power Termination System (FPTS). The MELCOR KSTAR input is made by scaling down the ITER input deck. So, the detail system is not same

  13. Modelling the association of dengue fever cases with temperature and relative humidity in Jeddah, Saudi Arabia-A generalised linear model with break-point analysis.

    Science.gov (United States)

    Alkhaldy, Ibrahim

    2017-04-01

    The aim of this study was to examine the role of environmental factors in the temporal distribution of dengue fever in Jeddah, Saudi Arabia. The relationship between dengue fever cases and climatic factors such as relative humidity and temperature was investigated during 2006-2009 to determine whether there is any relationship between dengue fever cases and climatic parameters in Jeddah City, Saudi Arabia. A generalised linear model (GLM) with a break-point was used to determine how different levels of temperature and relative humidity affected the distribution of the number of cases of dengue fever. Break-point analysis was performed to modelled the effect before and after a break-point (change point) in the explanatory parameters under various scenarios. Akaike information criterion (AIC) and cross validation (CV) were used to assess the performance of the models. The results showed that maximum temperature and mean relative humidity are most probably the better predictors of the number of dengue fever cases in Jeddah. In this study three scenarios were modelled: no time lag, 1-week lag and 2-weeks lag. Among these scenarios, the 1-week lag model using mean relative humidity as an explanatory variable showed better performance. This study showed a clear relationship between the meteorological variables and the number of dengue fever cases in Jeddah. The results also demonstrated that meteorological variables can be successfully used to estimate the number of dengue fever cases for a given period of time. Break-point analysis provides further insight into the association between meteorological parameters and dengue fever cases by dividing the meteorological parameters into certain break-points.

  14. Analysis of internal events for the Unit 1 of the Laguna Verde nuclear power station; Analisis de eventos internos para la Unidad 1 de la Central Nucleolelectrica de Laguna Verde

    Energy Technology Data Exchange (ETDEWEB)

    Huerta B, A.; Aguilar T, O.; Nunez C, A.; Lopez M, R. [Comision Nacional de Seguridad Nuclear y Salvaguardias, 03000 Mexico D.F. (Mexico)

    1993-07-01

    This volume presents the results of the starter event analysis and the event tree analysis for the Unit 1 of the Laguna Verde nuclear power station. The starter event analysis includes the identification of all those internal events which cause a disturbance to the normal operation of the power station and require mitigation. Those called external events stay beyond the reach of this study. For the analysis of the Laguna Verde power station eight transient categories were identified, three categories of loss of coolant accidents (LOCA) inside the container, a LOCA out of the primary container, as well as the vessel break. The event trees analysis involves the development of the possible accident sequences for each category of starter events. Events trees by systems for the different types of LOCA and for all the transients were constructed. It was constructed the event tree for the total loss of alternating current, which represents an extension of the event tree for the loss of external power transient. Also the event tree by systems for the anticipated transients without scram was developed (ATWS). The events trees for the accident sequences includes the sequences evaluation with vulnerable nucleus, that is to say those sequences in which it is had an adequate cooling of nucleus but the remoting systems of residual heat had failed. In order to model adequately the previous, headings were added to the event tree for developing the sequences until the point where be solved the nucleus state. This process includes: the determination of the failure pressure of the primary container, the evaluation of the environment generated in the reactor building as result of the container failure or cracked of itself, the determination of the localization of the components in the reactor building and the construction of boolean expressions to estimate the failure of the subordinated components to an severe environment. (Author)

  15. Development of novel visual-plus quantitative analysis systems for studying DNA double-strand break repairs in zebrafish.

    Science.gov (United States)

    Liu, Jingang; Gong, Lu; Chang, Changqing; Liu, Cong; Peng, Jinrong; Chen, Jun

    2012-09-20

    The use of reporter systems to analyze DNA double-strand break (DSB) repairs, based on the enhanced green fluorescent protein (EGFP) and meganuclease such as I-Sce I, is usually carried out with cell lines. In this study, we developed three visual-plus quantitative assay systems for homologous recombination (HR), non-homologous end joining (NHEJ) and single-strand annealing (SSA) DSB repair pathways at the organismal level in zebrafish embryos. To initiate DNA DSB repair, we used two I-Sce I recognition sites in opposite orientation rather than the usual single site. The NHEJ, HR and SSA repair pathways were separately triggered by the injection of three corresponding I-Sce I-cut constructions, and the repair of DNA lesion caused by I-Sce I could be tracked by EGFP expression in the embryos. Apart from monitoring the intensity of green fluorescence, the repair frequencies could also be precisely measured by quantitative real-time polymerase chain reaction (qPCR). Analysis of DNA sequences at the DSB sites showed that NHEJ was predominant among these three repair pathways in zebrafish embryos. Furthermore, while HR and SSA reporter systems could be effectively decreased by the knockdown of rad51 and rad52, respectively, NHEJ could only be impaired by the knockdown of ligaseIV (lig4) when the NHEJ construct was cut by I-Sce I in vivo. More interestingly, blocking NHEJ with lig4-MO increased the frequency of HR, but decreased the frequency of SSA. Our studies demonstrate that the major mechanisms used to repair DNA DSBs are conserved from zebrafish to mammal, and zebrafish provides an excellent model for studying and manipulating DNA DSB repair at the organismal level.

  16. Development of Novel Visual-Plus Quantitative Analysis Systems for Studying DNA Double-Strand Break Repairs in Zebrafish

    Institute of Scientific and Technical Information of China (English)

    Jingang Liu; Lu Gong; Changqing Chang; Cong Liu; Jinrong Peng; Jun Chen

    2012-01-01

    The use of reporter systems to analyze DNA double-strand break (DSB) repairs,based on the enhanced green fluorescent protein (EGFP) and meganuclease such as I-Sce Ⅰ,is usually carried out with cell lines.In this study,we developed three visual-plus quantitative assay systems for homologous recombination (HR),non-homologous end joining (NHEJ) and single-strand annealing (SSA) DSB repair pathways at the organismal level in zebrafish embryos.To initiate DNA DSB repair,we used two I-Sce Ⅰ recognition sites in opposite orientation rather than the usual single site.The NHEJ,HR and SSA repair pathways were separately triggered by the injection of three corresponding I-Sce I-cut constructions,and the repair of DNA lesion caused by I-Sce Ⅰ could be tracked by EGFP expression in the embryos.Apart from monitoring the intensity of green fluorescence,the repair frequencies could also be precisely measured by quantitative real-time polymerase chain reaction (qPCR).Analysis of DNA sequences at the DSB sites showed that NHEJ was predominant among these three repair pathways in zebrafish embryos.Furthermore,while HR and SSA reporter systems could be effectively decreased by the knockdown of rad51 and rad52,respectively,NHEJ could only be impaired by the knockdown of ligaseⅣ (lig4) when the NHEJ construct was cut by I-Sce Ⅰ in vivo.More interestingly,blocking NHEJ with lig4-MO increased the frequency of HR,but decreased the frequency of SSA.Our studies demonstrate that the major mechanisms used to repair DNA DSBs are conserved from zebrafish to mammal,and zebrafish provides an excellent model for studying and manipulating DNA DSB repair at the organismal level.

  17. New roles for astrocytes: the nightlife of an 'astrocyte'. La vida loca!

    Science.gov (United States)

    Horner, Philip J; Palmer, Theo D

    2003-11-01

    Like a newly popular nightspot, the biology of adult stem cells has emerged from obscurity to become one of the most lively new disciplines of the decade. The neurosciences have not escaped this trendy pastime and, from amid the noise and excitement, the astrocyte emerges as a beguiling companion to the adult neural stem cell. A once receding partner to neurons and oligodendrocytes, the astrocyte even takes on an alter ego of the stem cell itself (S. Goldman, this issue of TINS). Putting ego aside, the 'astrocyte' is also (and perhaps more importantly) an integral component of neural progenitor hotspots, where the craziness or 'la vida loca' of the nightlife might not be so wild when compared with our traditional understanding of the astrocyte. Here, astrocytes contribute to the instructive confluence of location, atmosphere and cellular neighbors that define the daily 'vida local' or everyday local life of an adult stem cell. This review discusses astrocytes as influential components in the local stem cell niche.

  18. Belgian experience in applying the {open_quotes}leak-before-break{close_quotes} concept to the primary loop piping

    Energy Technology Data Exchange (ETDEWEB)

    Gerard, R.; Malekian, C.; Meessen, O. [Tractebel Energy Engineering, Brussels (Belgium)

    1997-04-01

    The Leak Before Break (LBB) concept allows to eliminate from the design basis the double-ended guillotine break of the primary loop piping, provided it can be demonstrated by a fracture mechanics analysis that a through-wall flaw, of a size giving rise to a leakage still well detectable by the plant leak detection systems, remains stable even under accident conditions (including the Safe Shutdown Earthquake (SSE)). This concept was successfully applied to the primary loop piping of several Belgian Pressurized Water Reactor (PWR) units, operated by the Utility Electrabel. One of the main benefits is to permit justification of supports in the primary loop and justification of the integrity of the reactor pressure vessel and internals in case of a Loss Of Coolant Accident (LOCA) in stretch-out conditions. For two of the Belgian PWR units, the LBB approach also made it possible to reduce the number of large hydraulic snubbers installed on the primary coolant pumps. Last but not least, the LBB concept also facilitates the steam generator replacement operations, by eliminating the need for some pipe whip restraints located close to the steam generator. In addition to the U.S. regulatory requirements, the Belgian safety authorities impose additional requirements which are described in details in a separate paper. An novel aspect of the studies performed in Belgium is the way in which residual loads in the primary loop are taken into account. Such loads may result from displacements imposed to close the primary loop in a steam generator replacement operation, especially when it is performed using the {open_quote}two cuts{close_quotes} technique. The influence of such residual loads on the LBB margins is discussed in details and typical results are presented.

  19. SPES-2, AP600 intergral system test S01007 2 inch CL to core make-up tank pressure balance line break

    Energy Technology Data Exchange (ETDEWEB)

    Bacchiani, M.; Medich, C.; Rigamonti, M. [SIET S.p.A. Piacenza (Italy)] [and others

    1995-09-01

    The SPES-2 is a full height, full pressure experimental test facility reproducing the Westinghouse AP600 reactor with a scaling factor of 1/395. The experimental plant, designed and operated by SIET in Piacenza, consists of a full simulation of the AP600 primary core cooling system including all the passive and active safety systems. In 1992, Westinghouse, in cooperation with ENEL (Ente Nazionale per l` Energia Elettrica), ENEA (Enter per le numove Technlogie, l` Energia e l` Ambient), Siet (Societa Informazioni Esperienze Termoidraulich) and ANSALDO developed an experimental program to test the integrated behaviour of the AP600 passive safety systems. The SPES-2 test matrix, concluded in November 1994, has examined the AP600 passive safety system response for a range of small break LOCAs at different locations on the primary system and on the passive system lines; single steam generator tube ruptures with passive and active safety systems and a main steam line break transient to demonstrate the boration capability of passive safety systems for rapid cooldown. Each of the tests has provided detailed experimental results for verification of the capability of the analysis methods to predict the integrated passive safety system behaviour. Cold and hot shakedown tests have been performed on the facility to check the characteristics of the plant before starting the experimental campaign. The paper first presents a description of the SPES-2 test facility then the main results of S01007 test {open_quotes}2{close_quotes} Cold Leg (CL) to Core Make-up Tank (CMT) pressure balance line break{close_quotes} are reported and compared with predictions performed using RELAP5/mod3/80 obtained by ANSALDO through agreement with U.S.N.R.C. (U.S. Nuclear Regulatory Commission). The SPES-2 nodalization and all the calculations here presented were performed by ANSALDO and sponsored by ENEL as a part of pre-test predictions for SPES-2.

  20. Exploration of shape variation using localized components analysis.

    Science.gov (United States)

    Alcantara, Dan A; Carmichael, Owen; Harcourt-Smith, Will; Sterner, Kirstin; Frost, Stephen R; Dutton, Rebecca; Thompson, Paul; Delson, Eric; Amenta, Nina

    2009-08-01

    Localized Components Analysis (LoCA) is a new method for describing surface shape variation in an ensemble of objects using a linear subspace of spatially localized shape components. In contrast to earlier methods, LoCA optimizes explicitly for localized components and allows a flexible trade-off between localized and concise representations, and the formulation of locality is flexible enough to incorporate properties such as symmetry. This paper demonstrates that LoCA can provide intuitive presentations of shape differences associated with sex, disease state, and species in a broad range of biomedical specimens, including human brain regions and monkey crania.

  1. Beyond designed functional margins in CANDU type NPP. Radioactive nuclei assessment in an LOCA type accident

    Directory of Open Access Journals (Sweden)

    Budu Andrei Razvan

    2015-01-01

    Full Text Available European Union's energy roadmap up to year 2050 states that in order to have an efficient and sustainable economy, with minimum or decreasing greenhouse gas emissions, along with use of renewable resources, each constituent state has the option for nuclear energy production as one desirable option. Every scenario considered for tackling climate change issues, along with security of supply positions the nuclear energy as a recommended option, an option that is highly competitive with respect to others. Nuclear energy, along with other renewable power sources are considered to be the main pillars in the energy sector for greenhouse gas emission mitigation at European level. European Union considers that nuclear energy must be treated as a highly recommended option since it can contribute to security of energy supply. Romania showed excellent track-records in operating in a safe and economically sound manner of Cernavoda NPP Units 1&2. Both Units are in top 10 worldwide in terms of capacity factor. Due to Romania's need to ensure the security of electricity supply, to meet the environmental targets and to move to low carbon generation technologies, Cernavoda Units 3&4 Project appears as a must. This Project was started in 2010 and it is expected to have the Units running by 2025. Cost effective and safety operation of a Nuclear Power Plant is made taking into consideration functional limits of its equipment. As common practice, every nuclear reactor type (technology used is tested according to the worse credible accident or equipment failure that can occur. For CANDU type reactor, this is a Loss of Cooling Accident (LOCA. In a LOCA type accident in a CANDU NPP, using RELAP/SCDAP code for fuel bundle damage assessment the radioactive nuclei are to be quantified. Recently, CANDU type NPP accidents are studied using the RELAP/SCDAP code only. The code formerly developed for PWR type reactors was adapted for the CANDU geometry and can assess the

  2. 气爆式核桃破壳有限元力学分析%Finite Element Mechanics Analysis for Breaking Walnut Shell in Gas Explosion Type

    Institute of Scientific and Technical Information of China (English)

    周军; 史建新

    2014-01-01

    Breaking walnut shell is the key of processing walnut .According to the geometry parameters of walnut , a wal-nut finite element analysis model is established with software .Through the analysis of the load stress state stress and strain distribution under three kinds of pneumatic loading ways , we have obtained the analysis results that when a load is loaded at hole A at 0 .55 Mpa , the walnut shell burst open position is the best and it is the optimal solution .More rupture positions more conducive to breaking hull work and being able to get a higher breaking rate and a lower loss rate .We have proved the feasibility of this finite element analysis model .%核桃破壳取仁技术是核桃深加工工艺中的重点。为此,根据核桃的几何尺寸参数,用软件建立了核桃有限元分析模型,对核桃在3种气压载荷加载方式下的受力状态进行应力与应变分布分析。分析结果表明,在0.55 MPa载荷时核桃结蒂位置加载是最优解,核桃壳体爆开位置较好,多处破裂有利于取仁工作,可以得到较高的破壳率和较低的碎仁率,证明此有限元分析模型具有可行性。

  3. Break-glass handling exceptional situations in access control

    CERN Document Server

    Petritsch, Helmut

    2014-01-01

    Helmut Petritsch describes the first holistic approach to Break-Glass which covers the whole life-cycle: from access control modeling (pre-access), to logging the security-relevant system state during Break-Glass accesses (at-access), and the automated analysis of Break-Glass accesses (post-access). Break-Glass allows users to override security restrictions in exceptional situations. While several Break-Glass models specific to given access control models have already been discussed in research (e.g., extending RBAC with Break-Glass), the author introduces a generic Break-Glass model. The pres

  4. Development and Assessment of CFD Models Including a Supplemental Program Code for Analyzing Buoyancy-Driven Flows Through BWR Fuel Assemblies in SFP Complete LOCA Scenarios

    Science.gov (United States)

    Artnak, Edward Joseph, III

    This work seeks to illustrate the potential benefits afforded by implementing aspects of fluid dynamics, especially the latest computational fluid dynamics (CFD) modeling approach, through numerical experimentation and the traditional discipline of physical experimentation to improve the calibration of the severe reactor accident analysis code, MELCOR, in one of several spent fuel pool (SFP) complete loss-ofcoolant accident (LOCA) scenarios. While the scope of experimental work performed by Sandia National Laboratories (SNL) extends well beyond that which is reasonably addressed by our allotted resources and computational time in accordance with initial project allocations to complete the report, these simulated case trials produced a significant array of supplementary high-fidelity solutions and hydraulic flow-field data in support of SNL research objectives. Results contained herein show FLUENT CFD model representations of a 9x9 BWR fuel assembly in conditions corresponding to a complete loss-of-coolant accident scenario. In addition to the CFD model developments, a MATLAB based controlvolume model was constructed to independently assess the 9x9 BWR fuel assembly under similar accident scenarios. The data produced from this work show that FLUENT CFD models are capable of resolving complex flow fields within a BWR fuel assembly in the realm of buoyancy-induced mass flow rates and that characteristic hydraulic parameters from such CFD simulations (or physical experiments) are reasonably employed in corresponding constitutive correlations for developing simplified numerical models of comparable solution accuracy.

  5. Testing to evaluate synergistic effects from LOCA environments. Test IX. Simultaneous mode; cables, splice assemblies, and electrical insulation samples

    Energy Technology Data Exchange (ETDEWEB)

    Thome, F.V.

    1978-04-01

    This test was conducted to complement Test VIII which was a sequential test of cables, cable splices, and insulation samples. In this test, the generic LOCA environments (radiation, temperature, pressure, chemical spray) were simulated and simultaneously applied to the test items. There were no failures of any assemblies and all were able to function at rated current and voltage throughout the entire test. An additional parameter, dissipation factor, was monitored in this test and when used in conjunction with capacitance, provided a better indication of insulation degradation.

  6. Analysis and Verification of Direct Vessel Injection Line Break event tree for AP1000 reactor with TRACE code

    Energy Technology Data Exchange (ETDEWEB)

    Queral, C.; Montero-Mayorga, J.; Gonzalez-Cadelo, J.

    2013-07-01

    The AP1000 PRA thermal hydraulic simulations were performed with MAAP code, which allows simulating sequences with low computational efforts. On the other hand, the use of best estimate codes allows verifying PRA results as well as obtaining a greater knowledge of the phenomenology of such sequences. The initiating event with the greatest contribution to core damage is Direct Vessel Injection Line Break (DVILB). This paper presents a review of DVILB sequences of AP1000 with TRACE code for verifying sequences previously analyzed by Westinghouse with MAAP code. The sequences which configure the DVILB event tree during short term have been simulated. The results obtained confirm the ones obtained in AP1000 PRA.

  7. Validation of Advanced Computer Codes for VVER Technology: LB-LOCA Transient in PSB-VVER Facility

    Directory of Open Access Journals (Sweden)

    A. Del Nevo

    2012-01-01

    Full Text Available The OECD/NEA PSB-VVER project provided unique and useful experimental data for code validation from PSB-VVER test facility. This facility represents the scaled-down layout of the Russian-designed pressurized water reactor, namely, VVER-1000. Five experiments were executed, dealing with loss of coolant scenarios (small, intermediate, and large break loss of coolant accidents, a primary-to-secondary leak, and a parametric study (natural circulation test aimed at characterizing the VVER system at reduced mass inventory conditions. The comparative analysis, presented in the paper, regards the large break loss of coolant accident experiment. Four participants from three different institutions were involved in the benchmark and applied their own models and set up for four different thermal-hydraulic system codes. The benchmark demonstrated the performances of such codes in predicting phenomena relevant for safety on the basis of fixed criteria.

  8. Dynamical Supersymmetry Breaking

    CERN Document Server

    Shadmi, Y; Shadmi, Yael; Shirman, Yuri

    2000-01-01

    Supersymmetry is one of the most plausible and theoretically motivated frameworks for extending the Standard Model. However, any supersymmetry in Nature must be a broken symmetry. Dynamical supersymmetry breaking (DSB) is an attractive idea for incorporating supersymmetry into a successful description of Nature. The study of DSB has recently enjoyed dramatic progress, fueled by advances in our understanding of the dynamics of supersymmetric field theories. These advances have allowed for direct analysis of DSB in strongly coupled theories, and for the discovery of new DSB theories, some of which contradict early criteria for DSB. We review these criteria, emphasizing recently discovered exceptions. We also describe, through many examples, various techniques for directly establishing DSB by studying the infrared theory, including both older techniques in regions of weak coupling, and new techniques in regions of strong coupling. Finally, we present a list of representative DSB models, their main properties, an...

  9. Near-infrared spectroscopic analysis of the breaking force of extended-release matrix tablets prepared by roller-compaction: influence of plasticizer levels and sintering temperature.

    Science.gov (United States)

    Dave, Vivek S; Fahmy, Raafat M; Hoag, Stephen W

    2015-06-01

    The aim of this study was to investigate the feasibility of near-infrared (NIR) spectroscopy for the determination of the influence of sintering temperature and plasticizer levels on the breaking force of extended-release matrix tablets prepared via roller-compaction. Six formulations using theophylline as a model drug, Eudragit® RL PO or Eudragit® RS PO as a matrix former and three levels of TEC (triethyl citrate) as a plasticizer were prepared. The powder blend was roller compacted using a fixed roll-gap of 1.5 mm, feed screw speed to roller speed ratio of 5:1 and roll pressure of 4 MPa. The granules, after removing fines, were compacted into tablets on a Stokes B2 rotary tablet press at a compression force of 7 kN. The tablets were thermally treated at different temperatures (Room Temperature, 50, 75 and 100 °C) for 5 h. These tablets were scanned in reflectance mode in the wavelength range of 400-2500 nm and were evaluated for breaking force. Tablet breaking force significantly increased with increasing plasticizer levels and with increases in the sintering temperature. An increase in tablet hardness produced an upward shift (increase in absorbance) in the NIR spectra. The principle component analysis (PCA) of the spectra was able to distinguish samples with different plasticizer levels and sintering temperatures. In addition, a 9-factor partial least squares (PLS) regression model for tablets containing Eudragit® RL PO had an r(2) of 0.9797, a standard error of calibration of 0.6255 and a standard error of cross validation (SECV) of 0.7594. Similar analysis of tablets containing Eudragit® RS PO showed an r(2) of 0.9831, a standard error of calibration of 0.9711 and an SECV of 1.192.

  10. The prediction of pH by Gibbs free energy minimization in the sump solution under LOCA condition of PWR

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Hyoung Ju [Dept. of Nuclear Engineering, University of Kyunghee, Seoul (Korea, Republic of)

    2013-02-15

    It is required that the pH of the sump solution should be above 7.0 to retain iodine in a liquid phase and be within the material compatibility constraints under LOCA condition of PWR. The pH of the sump solution can be determined by conventional chemical equilibrium constants or by the minimization of Gibbs free energy. The latter method developed as a computer code called SOLGASMIX-PV is more convenient than the former since various chemical components can be easily treated under LOCA conditions. In this study, SOLGASMIX-PV code was modified to accommodate the acidic and basic materials produced by radiolysis reactions and to calculate the pH of the sump solution. When the computed pH was compared with measured by the ORNL experiment to verify the reliability of the modified code, the error between two values was within 0.3 pH. Finally, two cases of calculation were performed for the SKN 3 and 4 and UCN 1 and 2. As results, pH of the sump solution for the SKN 3 and 4 was between 7.02 and 7.45, and for the UCN 1 and 2 plant between 8.07 and 9.41. Furthermore, it was found that the radiolysis reactions have insignificant effects on pH because the relative concentrations of HCl, HNO3, and Cs are very low.

  11. THE PREDICTION OF pH BY GIBBS FREE ENERGY MINIMIZATION IN THE SUMP SOLUTION UNDER LOCA CONDITION OF PWR

    Directory of Open Access Journals (Sweden)

    HYOUNGJU YOON

    2013-02-01

    Full Text Available It is required that the pH of the sump solution should be above 7.0 to retain iodine in a liquid phase and be within the material compatibility constraints under LOCA condition of PWR. The pH of the sump solution can be determined by conventional chemical equilibrium constants or by the minimization of Gibbs free energy. The latter method developed as a computer code called SOLGASMIX-PV is more convenient than the former since various chemical components can be easily treated under LOCA conditions. In this study, SOLGASMIX-PV code was modified to accommodate the acidic and basic materials produced by radiolysis reactions and to calculate the pH of the sump solution. When the computed pH was compared with measured by the ORNL experiment to verify the reliability of the modified code, the error between two values was within 0.3 pH. Finally, two cases of calculation were performed for the SKN 3&4 and UCN 1&2. As results, pH of the sump solution for the SKN 3&4 was between 7.02 and 7.45, and for the UCN 1&2 plant between 8.07 and 9.41. Furthermore, it was found that the radiolysis reactions have insignificant effects on pH because the relative concentrations of HCl, HNO3, and Cs are very low.

  12. DRAWING BREAK ANALYSIS OF 45#HARD WIRE%45#硬线拉拔断裂分析

    Institute of Scientific and Technical Information of China (English)

    张海旺; 张敏; 汪鹏; 李朝辉

    2015-01-01

    针对45#硬线由Φ6.5 mm拉拔到Φ4.6 mm时发生断裂的问题,分析了其拉拔断口及表面裂纹形貌,用金相显微镜、扫描电镜对其金相组织、夹杂物及化学成分进行分析,结果表明:45#硬线钢中存在大颗粒脆性夹杂物,降低了盘条表面的强度和塑性,使其在拉拔过程中出现横裂纹,继而引起拉拔断裂,盘条表层组织不均匀也增加了盘条断裂机率。提出了夹杂物控制和金相组织改进措施,改进后盘条拉拔到Φ3.8 mm时的断丝率不足1.5%。%To solve the problem of 45#hard wire:breaking when drew from Φ6.5 to 4.6 mm, its fracture surface and the surface cracks morphology are analyzed as well as its metallographic structure, inclusion and chemical composition with metallographic microscope and SEM.It is showed from the result that there is large-size brittle inclusion in it and so the surface strength and plasticity of the wire bar reduced, and trans-verse crack takes place on it in drawing and then broken.Besides, not homogeneous surface structure of wire bar increases the rate of break.The measures in controlling inclusion and improving metallographic structure are proposed.After improvement the break rate of wire bar is below 1.5%when drew toΦ3.8 mm.

  13. Transient recovery voltage analysis for various current breaking mathematical models: shunt reactor and capacitor bank de-energization study

    Directory of Open Access Journals (Sweden)

    Oramus Piotr

    2015-09-01

    Full Text Available Electric arc is a complex phenomenon occurring during the current interruption process in the power system. Therefore performing digital simulations is often necessary to analyse transient conditions in power system during switching operations. This paper deals with the electric arc modelling and its implementation in simulation software for transient analyses during switching conditions in power system. Cassie, Cassie-Mayr as well as Schwarz-Avdonin equations describing the behaviour of the electric arc during the current interruption process have been implemented in EMTP-ATP simulation software and presented in this paper. The models developed have been used for transient simulations to analyse impact of the particular model and its parameters on Transient Recovery Voltage in different switching scenarios: during shunt reactor switching-off as well as during capacitor bank current switching-off. The selected simulation cases represent typical practical scenarios for inductive and capacitive currents breaking, respectively.

  14. Proceedings of the seminar on leak before break in reactor piping and vessels

    Energy Technology Data Exchange (ETDEWEB)

    Faidy, C. [ed.] [Electricite de France, Villeurbanne (France); Gilles, P. [ed.] [Framatome, Paris (France)

    1997-04-01

    The objective of the seminar was to present the current state of the art in Leak-Before-Break (LBB) methodology development, validation, and application in an international forum. With particular emphasis on industrial applications and regulatory policies, the seminar provided an opportunity to compare approaches, experiences, and codifications developed by different countries. The seminar was organized into four topic areas: status of LBB applications; technical issues in LBB methodology; complementary requirements (leak detection and inspection); LBB assessment and margins. As a result of this seminar, an improved understanding of LBB gained through sharing of different viewpoints from different countries, permits consideration of: simplified pipe support design and possible elimination of loss-of-coolant-accident (LOCA) mechanical consequences for specific cases; defense-in-depth type of applications without support modifications; support of safety cases for plants designed without the LOCA hypothesis. In support of these activities, better estimates of the limits to the LBB approach should follow, as well as an improvement in codifying methodologies. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  15. Analytical model for estimating drag forces on rigid submerged structures caused by LOCA and safety relief valve ramshead air discharges. [BWR

    Energy Technology Data Exchange (ETDEWEB)

    1977-09-01

    Basic information is presented for estimating drag forces on rigid structural members submerged in a pressure suppression pool, caused by either the air discharge from a loss-of-coolant accident (LOCA), or the air bubble oscillation following safey relief valve ramshead discharge. Methods are described for estimating acceleration (unsteady) and standard (velocity-squared) drag force components for a variety of structural geometries.

  16. Topological amplitudes in $D$ decays to two pseudoscalars: a global analysis with linear $SU(3)_F$ breaking

    CERN Document Server

    Müller, Sarah; Schacht, Stefan

    2015-01-01

    We study decays of $D^0$, $D^+$, and $D_s^+$ mesons into two pseudoscalar mesons by expressing the decay amplitudes in terms of topological amplitudes. Including consistently SU(3)$_F$ breaking to linear order, we show how the topological-amplitude decomposition can be mapped onto the standard expansion using reduced amplitudes characterized by SU(3) representations. The tree and annihilation amplitudes can be calculated in factorization up to corrections which are quadratic in the color-counting parameter $1/N_c$. We find new sum rules connecting $D^+\\rightarrow K_SK^+$, $D_s^+\\rightarrow K_S\\pi^+$ and $D^+\\rightarrow K^+\\pi^0$, which test the quality of the $1/N_c$ expansion. Subsequently, we determine the topological amplitudes in a global fit to the data, taking the statistical correlations among the various measurements into account. We carry out likelihood ratio tests in order to quantify the role of specific topological contributions. While the SU(3)$_F$ limit is excluded with a significance of more th...

  17. Evolutionary break point analysis between the proximal half of bovine chromosome 27 and conserved segments of the human genome.

    Science.gov (United States)

    Goldammer, T; Kuehn, C; Brunner, R M; Weikard, R

    2009-01-01

    The proximal half of Bos taurus chromosome 27 (BTA27prox) delimited by microsatellite markers BM3507 and CSSM043 reveals complex rearrangements compared to its corresponding Homo sapiens chromosome (HSA) fragments. A comparative mapping approach combining somatic and radiation hybrid cell mapping techniques and related cytogenetic data resulted in an improved physical map for BTA27prox, which provides candidate genes for several important economic traits. The generated comprehensive map includes anchor loci for 103 genes and microsatellite markers. Mapping of genes proximal to BM3507 matching a region from 0.60 to 2.78 megabase pairs (Mb) of HSA8 confirmed recent sequence annotations on BTA27. Assignments of loci predicted to be on BTA27 to BTA1, BTA8, and BTA17 narrowed down evolutionary chromosome break points compared with corresponding chromosome segments in human. New physical anchors obtained in this study confirm in more detail the described evolutionary conservation between the proximal half of BTA27 and homologous segments of HSA4 and HSA8 and will contribute to the completion of the cattle DNA genome sequence.

  18. Preliminary Analysis of a Steam Line Break Accident with the MARS-KS code for the SMART Design with Passive Safety Systems

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Doohyuk; Ko, Yungjoo; Suh, Jaeseung [Hannam Univ., Daejeon (Korea, Republic of); Bae, Hwang; Ryu, Sunguk; Yi, Sungjae; Park, Hyunsik [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    SMART has been developed by KAERI, and SMART-Standard Design Approval (SDA) was recently granted in 2012. A SMART design with Passive Safety System (PSS) features (called SMART-PSS) is being developed and added to the standard design of SMART by KAERI to improve its safety system. Active safety systems such as safety injection pumps will be replaced by a passive safety system, which is actuated only by the gravity force caused by the height difference. All tanks for the passive safety systems are higher than the injection nozzle, which is located around the reactor coolant pumps (RCPs). In this study, a preliminary analysis of the main steam line break accident (MSLB) was performed using the MARS-KS code to understand the general behavior of the SMART-PSS design and to prepare its validation test with the SMART-ITL (FESTA) facility. An anticipated accident for the main steam line break (MSLB) was performed using the MARS-KS code to understand the thermal-hydraulic behaviors of the SMART-PSS design. The preliminary analysis provides good insight into the passive safety system design features of the SMART-PSS and the thermal-hydraulic characteristics of the SMART design. The analysis results of the MSLB showed that the core water collapsed level inside the core support barrel was maintained high over the active core top level during the transient period. Therefore, the SMART-PSS design has satisfied the requirements to maintain the plant at a safe shutdown condition during 72 hours without AC power or operator action after an anticipated accident.

  19. 液态光学透明胶的制备及特性研究%Study on preparation and characteristics of LOCA

    Institute of Scientific and Technical Information of China (English)

    赵迎波; 何利军; 李守平; 史伟同

    2015-01-01

    介绍了液态透明胶在触摸屏中的应用。它主要用于电容式触摸屏中触控模组与显示模组的贴合,起到填充、固定、提高对比度等作用。制备了一种液态光学透明胶(Liquid Optical Clear Adhesive-LOCA),重点研2究了其光学性能、固化性能和耐老化性能;结果表明,所制备的液态透明胶在3000 mJ/cm的固化能量下可以完全固化,黏度适用于各种贴合工艺;其透光率在99%以上,黄变指数和雾度小于0.2%,且具有优异的抗老化性能。%The main application of liquid optical clear adhesive(LOCA) in the capacitive touch screen was introduced, including the laminating of touch panel with LCD module and playing the role of fixing, filling and contrast enhancement.The LOCA was preparaed and its optical property, curing property and environmental reliability were studied. 2Results show that the LOCA has completely cured under the energy of 3 000 mJ/cm . The LOCA with a moderate viscosity can be used for various laminating process. The transmittance is over 99%, while the yellowing index and haze are less than 0.2. The LOCA also has a excellent environmental reliability.

  20. Pressure vessel fracture studies pertaining to a PWR LOCA-ECC thermal shock: experiments TSE-1 and TSE-2

    Energy Technology Data Exchange (ETDEWEB)

    Cheverton, R.D.

    1976-09-01

    The LOCA-ECC Thermal Shock Program was established to investigate the potential for flaw propagation in pressurized-water reactor (PWR) vessels during injection of emergency core coolant following a loss-of-coolant accident. Studies thus far have included fracture mechanics analyses of typical PWRs, the design and construction of a thermal shock test facility, determination of material properties for test specimens, and two thermal shock experiments with 0.53-m-OD (21-in.) by 0.15-m-wall (6-in.) cylindrical test specimens. The PWR calculations indicated that under some circumstances crack propagation could be expected and that experiments should be conducted for cracks that would have the potential for propagation at least halfway through the wall.

  1. Validation methodology for the evaluation of thermal-hydraulic sub-channel codes devoted to LOCA simulations

    Energy Technology Data Exchange (ETDEWEB)

    Seiler, N.; Ruyer, P.; Biton, B., E-mail: nathalie.seiler@irsn.fr, E-mail: pierre.ruyer@irsn.fr [IRSN/DPAM/SEMCA/LEMAR, CE Cadarache, Saint Paul lez Durance (France)

    2011-07-01

    This study focuses on thermal-hydraulic simulations, at sub-channel scale, of a damaged PWR reactor core during a Loss Of Coolant Accident (LOCA). The aim of this study is to accurately simulate the thermal-hydraulics to provide the thermal-mechanical code DRACCAR with an accurate wall heat transfer law. This latter code is developed by the French Safety Institute “Institut de Radioprotection et de Surete Nucleaire” (IRSN) to evaluate the thermics and deformations of fuel assemblies within the core. The present paper first describes the methodology considered to evaluate the capabilities of existing codes CATHARE-3 and CESAR to simulate dispersed droplet flows at a sub-channel scale and then provides some first evaluations of them. (author)

  2. Superconductivity and symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Sarasua, L.G., E-mail: sarasua@fisica.edu.uy [Instituto de Fisica, Facultad de Ciencias, Universidad de la Republica, Montevideo (Uruguay)

    2012-02-15

    In the present work we consider the relation between superconductivity and spontaneous gauge symmetry breaking (SGBS). We show that ODLRO does not require in principle SBGS, even in the presence of particle number fluctuations, by examining exact solutions of a fermionic pairing model. The criteria become equivalent if a symmetry breaking field is allowed, which can be attributed to the interaction with the environment. However, superconducting states without SBGS are not forbidden.

  3. Ice-Induced Fatigue Analysis by Spectral Approach for Offshore Jacket Platforms with Ice-Breaking Cones

    Institute of Scientific and Technical Information of China (English)

    YUE Qian-jin; LIU Yuan; ZHANG Ri-xiang; QU Yan; WANG Rui-xue

    2007-01-01

    The spectral methods and ice-induced fatigue analysis are discussed based on Miner's linear cumulative fatigue hypothesis and S-N curve data.According to the long-term data of full-scale tests on the platforms in the Bohai Sea,the ice force spectrum of conical structures and the fatigue environmental model are established.Moreover,the finite element model of JZ20-2MSW platform,an example of ice-induced fatigue analysis,is built with ANSYS software.The mode analysis and dynamic analysis in frequency domain under all kinds of ice fatigue work conditions are carried on,and the fatigue life of the structure is estimated in detail.The methods in this paper can be helpful in ice-induced fatigue analysis of ice-resistant platforms.

  4. Electroweak symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Chanowitz, M.S.

    1990-09-01

    The Higgs mechanism is reviewed in its most general form, requiring the existence of a new symmetry-breaking force and associated particles, which need not however be Higgs bosons. The first lecture reviews the essential elements of the Higgs mechanism, which suffice to establish low energy theorems for the scattering of longitudinally polarized W and Z gauge bosons. An upper bound on the scale of the symmetry-breaking physics then follows from the low energy theorems and partial wave unitarity. The second lecture reviews particular models, with and without Higgs bosons, paying special attention to how the general features discussed in lecture 1 are realized in each model. The third lecture focuses on the experimental signals of strong WW scattering that can be observed at the SSC above 1 TeV in the WW subenergy, which will allow direct measurement of the strength of the symmetry-breaking force. 52 refs., 10 figs.

  5. Sign restrictions and statistical identification under volatility breaks -- Simulation based evidence and an empirical application to monetary policy analysis

    OpenAIRE

    2014-01-01

    Apart from a priori assumptions on instantaneous or long run effects of structural shocks, sign restrictions have become a prominent means for structural vector autoregressive (SVAR) analysis. Moreover, second order heterogeneity of systems of times series can be fruitfully exploited for identification purposes in SVARs. We show by means of a Monte Carlo study that taking statistical information into account offers a more accurate quantification of the true structural relations. In contrast, ...

  6. Experimental Study of a Stoppage Natural Circulation during a Nuclear Heating Reactor LOCA

    Institute of Scientific and Technical Information of China (English)

    博金海; 张佑杰; 姜胜耀

    2001-01-01

    The 5MW nuclear heating reactor is an integral naturalcirculation reactor. The rupture of the coolant penetrating tube is a typical accident causing coolant loss. When the water level drops down to the upper edge of the inlet of the heat exchanger, the natural circulation stops. This influences the core cooling and the stability of the main loop. A series of tests showed that there is a stable drop of pressure, and the heated element temperature is not too high to cause burnout. But the backward flow or flow oscillation in the primary coolant circuit occurs when the flow breaks completely in the end. The whole flow process is described and the mechanism is discussed.

  7. 基于SolidWorks的破茬开沟犁刀的设计与强度分析%Design of Stubble-breaking Ditching Colter Based on SolidWorks and Its Strength Analysis

    Institute of Scientific and Technical Information of China (English)

    何磊; 周亚立; 刘向新; 赵岩

    2011-01-01

    破茬装置是茬地免耕播种机的关键工作部件,直接影响着播种机的播种质量,本文在目前国内所使用的破茬装置的基础上,设计出一种新型的破茬开沟犁刀。为研究其强度特性,减少工作时的故障,应用SolidWorks建立了破茬开沟犁刀的三维模型,用Cosmos对其进行了有限元分析,得到破茬开沟犁刀在工作时的变形和应力大小,找出了其强度薄弱环节。结果表明,破茬开沟犁刀的最大应力为5.862×108N/m2,最大扭曲位移为2.648mm,对破茬开沟犁刀进行了改进设计,应用Cosmos进行静态分析,表明改进后破茬开沟犁刀的强度和刚度明显提高,为其优化设计提供了参考依据。%Stubble-breaking device is a key working part of no-tillage seeder in stub land,and directly affects planting quality of seeder.Based on the current domestic used stubble-breaking device,a new kind of stubble-breaking ditching colter was designed.To study its strength property and reduce trouble in work,the three-dimensional model of stubble-breaking ditching colter was established based on SolidWorks.By using Cosmos,it was carried out the finite element analysis.The distortion and stress of stubble-breaking ditching colter in work were obtained,and the weak link of strength was found.The result showed that the maximum stress of stubble-breaking ditching colter was 5.862×108 N/m2,and the maximum twisted displacement was 2.648 mm.The stubble-breaking ditching colter was carried out improved design.Based on Cosmos,the static analysis was carried out.It showed that the strength and rigidity of improved stubble-breaking ditching colter were obviously improved.The research provided reference basis for optimal design of the stubble-breaking ditching colter.

  8. Cause Analysis of Break of Leveling Wire Rope for Wiggins Gasholder and Countermeasures%威金斯气柜调平钢丝绳断丝原因分析及解决措施

    Institute of Scientific and Technical Information of China (English)

    张善明; 张文义; 梁明明; 张天寿

    2016-01-01

    通过威金斯气柜调平钢丝绳损伤机理的分析,经过钢丝绳破断拉力计算,查找钢丝绳断丝的原因,提出了调平钢丝绳的选型。%Through analysis of the damage mechanism of the leveling wire rope for Wiggins gasholder and calculation of the breaking force of wire rope, the cause of wire break was found out and type selection method for the level wire rope was recommended.

  9. An attempt for a unified description of mechanical testing on Zircaloy-4 cladding subjected to simulated LOCA transient

    Directory of Open Access Journals (Sweden)

    Desquines Jean

    2016-01-01

    Full Text Available During a Loss Of Coolant Accident (LOCA, an important safety requirement is that the reflooding of the core by the emergency core cooling system should not lead to a complete rupture of the fuel rods. Several types of mechanical tests are usually performed in the industry to determine the degree of cladding embrittlement, such as ring compression tests or four-point bending of rodlets. Many other tests can be found in the open literature. However, there is presently no real intrinsic understanding of the failure conditions in these tests which would allow translation of the results from one kind of mechanical testing to another. The present study is an attempt to provide a unified description of the failure not directly depending on the tested geometry. This effort aims at providing a better understanding of the link between several existing safety criteria relying on very different mechanical testing. To achieve this objective, the failure mechanisms of pre-oxidized and pre-hydrided cladding samples are characterized by comparing the behavior of two different mechanical tests: Axial Tensile (AT test and “C”-shaped Ring Compression Test (CCT. The failure of samples in both cases can be described by usual linear elastic fracture mechanics theory. Using interrupted mechanical tests, metallographic examinations have evidenced that a set of parallel cracks are nucleated at the inner and outer surface of the samples just before failure, crossing both the oxide layer and the oxygen rich alpha layer. The stress intensity factors for multiple crack geometry are determined for both AT and CCT samples using finite element calculations. After each mechanical test performed on high temperature steam oxidized samples, metallography is then used to individually determine the crack depth and crack spacing. Using these two important parameters and considering the applied load at fracture, the stress intensity factor at failure is derived for each tested

  10. Model Breaking Points Conceptualized

    Science.gov (United States)

    Vig, Rozy; Murray, Eileen; Star, Jon R.

    2014-01-01

    Current curriculum initiatives (e.g., National Governors Association Center for Best Practices and Council of Chief State School Officers 2010) advocate that models be used in the mathematics classroom. However, despite their apparent promise, there comes a point when models break, a point in the mathematical problem space where the model cannot,…

  11. What records have we been breaking

    Science.gov (United States)

    Bartholow, J.M.; Milhous, R.

    2002-01-01

    a??Today was another record-breaking day,a?? the evening radio or television declares. High temperatures, low temperatures, floods, drought a?? take your choice. But how can we put these pronouncements in perspective? What do they really mean? We present two types of information in this article: 1) an analysis of daily air temperature and precipitation for Fort Collins and 2) an analysis of annual precipitation for Fort Collins. Each analysis provides a different meaning to the statement about a record-breaking day or year.

  12. Importance of water quality on plant abundance and diversity in high-alpine meadows of the Yerba Loca Natural Sanctuary at the Andes of north-central Chile Importancia de la calidad del agua sobre la abundancia y diversidad vegetal en vegas altoandinas del Santuario Natural Yerba Loca en los Andes de Chile centro-norte

    Directory of Open Access Journals (Sweden)

    ROSANNA GINOCCHIO

    2008-12-01

    Full Text Available Porphyry Cu-Mo deposits have influenced surface water quality in high-Andes of north-central Chile since the Miocene. Water anomalies may reduce species abundance and diversity in alpine meadows as acidic and metal-rich waters are highly toxic to plants The study assessed the importance of surface water quality on plant abundance and diversity in high-alpine meadows at the Yerba Loca Natural Santuary (YLNS, central Chile (33°15' S, 70°18' W. Hydrochemical and plant prospecting were carried out on Piedra Carvajal, Chorrillos del Plomo and La Lata meadows the growing seasons of 2006 and 2007. Direct gradient analysis was performed through canonical correspondence analysis (CCA to look for relationships among water chemistry and plant factors. High variability in water chemistry was found inside and among meadows, particularly for pH, sulphate, electric conductivity, hardness, and total dissolved Cu, Zn, Cd, Pb and Fe. Data on species abundance and water chemical factors suggests that pH and total dissolved Cu are very important factor determining changes in plant abundance and diversity in study meadows. For instance, Festuca purpurascens, Colobanthus quitensis, and Arenaria rivularis are abundant in habitals with Cu-rich waters while Festuca magellanica, Patosia clandestina, Plantago barbata, Werneria pygmea, and Erigeron andícola are abundant in habitals with dilute waters.Los megadepósitos de pórfidos de Cu-Mo han influido sobre la calidad de las aguas superficiales en las zonas altoandinas del centro-norte de Chile desde el Mioceno. Estas alteraciones en la calidad de las aguas podrían afectar negativamente a la vegetación presente en las vegas altoandinas, ya que las aguas acidas y ricas en metales son altamente tóxicas para las plantas. En este estudio se evaluó el efecto de la calidad de las aguas en la abundancia y diversidad florística de las vegas altoandinas del Santuario de la Naturaleza Yerba Loca (SNYL, en Chile central (33

  13. Breaking Computational Barriers: Real-time Analysis and Optimization with Large-scale Nonlinear Models via Model Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Carlberg, Kevin Thomas [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Quantitative Modeling and Analysis; Drohmann, Martin [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Quantitative Modeling and Analysis; Tuminaro, Raymond S. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Computational Mathematics; Boggs, Paul T. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Quantitative Modeling and Analysis; Ray, Jaideep [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Quantitative Modeling and Analysis; van Bloemen Waanders, Bart Gustaaf [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Optimization and Uncertainty Estimation

    2014-10-01

    -model errors. This enables ROMs to be rigorously incorporated in uncertainty-quantification settings, as the error model can be treated as a source of epistemic uncertainty. This work was completed as part of a Truman Fellowship appointment. We note that much additional work was performed as part of the Fellowship. One salient project is the development of the Trilinos-based model-reduction software module Razor , which is currently bundled with the Albany PDE code and currently allows nonlinear reduced-order models to be constructed for any application supported in Albany. Other important projects include the following: 1. ROMES-equipped ROMs for Bayesian inference: K. Carlberg, M. Drohmann, F. Lu (Lawrence Berkeley National Laboratory), M. Morzfeld (Lawrence Berkeley National Laboratory). 2. ROM-enabled Krylov-subspace recycling: K. Carlberg, V. Forstall (University of Maryland), P. Tsuji, R. Tuminaro. 3. A pseudo balanced POD method using only dual snapshots: K. Carlberg, M. Sarovar. 4. An analysis of discrete v. continuous optimality in nonlinear model reduction: K. Carlberg, M. Barone, H. Antil (George Mason University). Journal articles for these projects are in progress at the time of this writing.

  14. A Review of Dangerous Dust in Fusion Reactors: from Its Creation to Its Resuspension in Case of LOCA and LOVA

    Directory of Open Access Journals (Sweden)

    Andrea Malizia

    2016-07-01

    Full Text Available The choice of materials for the future nuclear fusion reactors is a crucial issue. In the fusion reactors, the combination of very high temperatures, high radiation levels, intense production of transmuting elements and high thermomechanical loads requires very high-performance materials. Erosion of PFCs (Plasma Facing Components determines their lifetime and generates a source of impurities (i.e., in-vessel tritium and dust inventories, which cool down and dilute the plasma. The resuspension of dust could be a consequences of LOss of Coolant Accidents (LOCA and LOss of Vacuum Accidents (LOVA and it can be dangerous because of dust radioactivity, toxicity, and capable of causing an explosion. These characteristics can jeopardize the plant safety and pose a serious threat to the operators. The purpose of this work is to determine the experimental and numerical steeps to develop a numerical model to predict the dust resuspension consequences in case of accidents through a comparison between the experimental results taken from campaigns carried out with STARDUST-U and the numerical simulation developed with CFD codes. The authors in this work will analyze the candidate materials for the future nuclear plants and the consequences of the resuspension of its dust in case of accidents through the experience with STARDUST-U.

  15. Breaking News as Radicalisation

    DEFF Research Database (Denmark)

    Hartley, Jannie Møller

    The aim of the paper is to make explicit how the different categories are applied in the online newsroom and thus how new categories can be seen as positioning strategies in the form of radicalisations of already existing categories. Thus field theory provides us with tools to analyse how online...... journalists are using the categorisations to create hierarchies within the journalistic field in order to position themselves as specialists in what Tuchman has called developing news, aiming and striving for what today is know as breaking news and the “exclusive scoop,” as the trademark of online journalism...... provides us with the following two research questions: How does the category of breaking news fit into Tuchmans typology related to time, planning and technology? What types of stories are providing journalistic capital and how are online news stories categorised relatively within the journalistic field?...

  16. Predicting appointment breaking.

    Science.gov (United States)

    Bean, A G; Talaga, J

    1995-01-01

    The goal of physician referral services is to schedule appointments, but if too many patients fail to show up, the value of the service will be compromised. The authors found that appointment breaking can be predicted by the number of days to the scheduled appointment, the doctor's specialty, and the patient's age and gender. They also offer specific suggestions for modifying the marketing mix to reduce the incidence of no-shows.

  17. Single sector supersymmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Luty, Markus A.; Terning, John

    1999-03-18

    We review recent work on realistic models that break supersymmetry dynamically and give rise to composite quarks and leptons, all in a single sector. These models have a completely natural suppression of flavor-changing neutral currents, and the hierarchy of Yukawa couplings is explained by the dimensionality of composite states. The generic signatures are unification of scalar masses with different quantum numbers at the compositeness scale, and lighter gaugino, Higgsino, and third-generation sfermion masses.

  18. An experimental study of the corrosion and precipitation of aluminum in the presence of trisodium phosphate buffer following a loss of coolant accident (LOCA) scenario

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Jun [Department of Nuclear Engineering, University of New Mexico (United States); Howe, Kerry J. [Department of Civil Engineering, University of New Mexico (United States); Leavitt, Janet J. [Department of Civil Engineering, University of New Mexico (United States); Alion Science and Technology (United States); Hammond, Kyle; Mitchell, Lana [Department of Civil Engineering, University of New Mexico (United States); Kee, Ernie [South Texas Project Nuclear Operating Company (STPNOC) (United States); Blandford, Edward D., E-mail: edb@unm.edu [Department of Nuclear Engineering, University of New Mexico (United States)

    2015-02-15

    Highlights: • Experimental head loss testing was conducted by aggressively promoting corrosion in loss of coolant accidents. • Blender-processed debris beds have higher head loss but tend to be less reproducible than NEI-processed debris beds. • Precipitation was observed from aluminum concentration and turbidity measurements. • Precipitation results were compared to predictions from Visual MINTEQ. - Abstract: This paper presents the results of an integrated chemical effects experiment of head loss across the sump pump screen with fibrous debris bed over a non-prototypical 10-day post-LOCA incident window. The corrosion head loss experiments (CHLE) is a reduced scaled integral effects testing facility built at the University of New Mexico (UNM) to investigate potential chemical effects on head loss across prepared fibrous debris beds. The results in this paper come from two integral effect tests performed at UNM in order to determine the chemical effects on head loss induced by a zinc source effect and an aluminum precipitation effect (T3: without Zn source case, T4: with Zn source case in containment). The tests were performed with a large surface area of aluminum coupons in the testing facility for an extended period of elevated temperature to accelerate corrosion above that expected under prototypical conditions. These conditions were sufficient to force aluminum precipitation to occur and induce the onset of chemical effects on debris bed head loss. The head loss behavior on two different types of fiber debris beds (blender-processed and NEI-processed debris bed) was evaluated in this study. It was found that the blender-processed bed is much more sensitive in filtering than the NEI-processed bed and consequently had a much higher head loss value across the beds. Aluminum precipitation was observed, with aluminum concentration and turbidity measurements, to form starting on day 7 in Test T3 and on day 6 in Test T4. The onset of aluminum precipitation

  19. A Comprehensive Analysis of the Swift/XRT Data: III. Jet Break Candidates in the X-ray and Optical Afterglow Lightcurves

    CERN Document Server

    Liang, En-Wei; Zhang, Bing; Zhang, Bin-Bin; Burrows, David N

    2007-01-01

    The Swift/XRT data of 179 GRBs (from 050124 to 070129) and the optical afterglow data of 57 pre- and post-Swift GRBs are analyzed, in order to systematically investigate the jet-like breaks in the X-ray and optical afterglow lightcurves. We find that not a single burst can be included in the ``Platinum'' sample, in which the data satisfy all the criteria of a jet break. By releasing one or more requirements to define a jet break, some candidates of various degrees could be identified. In the X-ray band, 42 out of the 109 well-sampled X-ray lightcurves have a decay slope of the post-break segment >1.5 (``Bronze'' sample), and 27 of them also satisfy the closure relations of the forward models (``Silver'' sample). The numbers of the ``Bronze'' and ``Silver'' candidates in the optical lightcurves are 27 and 23, respectively. Thirteen bursts have well-sampled optical and X-ray lightcurves, but only seven cases are consistent with an achromatic break, but even in these cases only one band satisfies the closure rel...

  20. 水平巷道贯通控制测量误差预计及精度分析%Error estimate and accuracy analysis of horizontal tunnel breaking through control survey

    Institute of Scientific and Technical Information of China (English)

    张路平

    2011-01-01

    贯通工程的质量直接影响矿山的安全生产,提高贯通测量精度是确保贯通工程质量的关键.详细介绍了黑龙江乌拉嘎金矿西露天采场70中段巷道硐口点到竖井70中段外延巷道600 m贯通测量方法,并对贯通测量进行了误差预计和精度分析;提出了贯通测量施测中应注意的问题,值得借鉴.%The quality of breaking through influences the mining production safety directly.And the survey accuracy is the key point to ensure the breaking through quality.The paper introduces the survey method of 600 m-long breaking through between tunnel of 70 m midsection in the west openpit and the extension tunnel of 70 m midsection in the shaft.The survey error estimate and accuracy analysis in Wulaga gold mine is carried out as well.Some attentions in breaking through survey are proposed for references in future.

  1. Accident Process and Consequence Research for LOCA Combining with Blackout Accident of Ship Reactor%船用堆破口叠加全船断电事故进程及后果研究

    Institute of Scientific and Technical Information of China (English)

    张帆; 陈航; 张彦招; 晏峰

    2015-01-01

    Using MELCOR code ,the combination of LOCA and blackout accident of ship reactor was modeled and calculated , and the accident process and source term release were researched . The results show that the accident leads to lower head of pressure vessel and bilge creep‐rupture finally without emergency power .The release fraction of inert gases and iodine are above 80% ,the main form of iodine is CsI with great deposit and less airborne fraction .The accident process is decided by the equiva‐lent diameter of break size .The production of H2 is decided by core temperature and water remaining in the core ,but has nothing to do with equivalent diameter of break size .T he probability of H2 detonation is unlikely to occur .T he results can provide tech‐nical support for emergency maintenance and emergency decision‐making .%采用M ELCOR程序,对船用堆破口叠加全船断电事故进行建模计算,并对事故进程和源项释放进行了研究。计算结果表明:若应急电源无法投入,最终将导致压力容器下封头失效和舱底失效;所研究事故的惰性气体、碘释放量均在80%以上,且释放的I主要以CsI形式存在,滞留量大,气载量小。事故进展快慢取决于破口当量尺寸,但氢气的产量与堆芯温度、堆芯残余水量相关,与破口当量尺寸无直接关系,堆舱内发生氢爆可能性不大。本文计算结果可为应急抢修和应急决策提供技术支持。

  2. Breaking the Waves

    DEFF Research Database (Denmark)

    Christensen, Poul Rind; Kirketerp, Anne

    2006-01-01

    The paper shortly reveals the history of a small school - the KaosPilots - dedicated to educate young people to carriers as entrepreneurs. In this contribution we want to explore how the KaosPilots managed to break the waves of institutionalised concepts and practices of teaching entrepreneurship....... Following the so-called 'Dogma' concept developed by Danish filmmakers, this contribution aim to explore the key elements making up the recipes guiding the entrepreneurship training program exercised by the school. Key factors forming a community of learning practice are outlined as well as the critical...... pedagogical elements on which the education in entrepreneurship rests....

  3. 磨料水射流钻头破岩过程的力学分析%Mechanical analysis of rock breaking by an abrasive water jet bit

    Institute of Scientific and Technical Information of China (English)

    卢义玉; 沈晓莹; 汤积仁; 夏彬伟; 王景环

    2012-01-01

    The boss at the hole bottom is a key factor that limits drilling speed. The boss was eliminated and drilling speed increased by using an abrasive water jet bit to drill in hard rock. Force analysis shows that the mode of rock breaking during hard rock drilling by a three wings bit is by grinding. However, the mode is by cutting when an abrasive water jet is used. Hard rock drilling experiments showed that the drilling speed was 1. 57 times faster using an improved bit with reduced blade distance of the leading bit compared to the original three wings bit. At the same time torque increased by 11.3%, and the observed wear is serious. The drill- ing speed using an abrasive water jet bit is 3.72 times faster than the original three wings bit and the torque is reduced by 34.0% with no evident wear. Theoretical analysis and experimen- tal results showed that low drilling speeds and serious wear encountered while drilling in hard rock can be completely resolved by using an abrasive water jet bit.%研究发现钻孔孔底凸台是限制钻头钻进速度的关键因素,为了消除凸台,提高钻进速度,提出利用磨料水射流钻头破碎硬岩.对原三翼钻头和磨料水射流钻头破岩过程进行了受力分析得出原三翼钻头硬岩钻进时破岩方式为磨削,磨料水射流钻头破岩方式为切削.实验室硬岩钻进实验表明:缩小前导钻头刀片间距的改良型钻头钻进速度是原三翼钻头的1.57倍,扭矩比原三翼钻头增大了11.3%,且磨损加剧;磨料水射流钻头钻进速度是原三翼钻头的3.72倍,扭矩比原三翼钻头减小34.0%,未见明显磨损.理论分析和实验结果表明,磨料水射流钻头从根本上解决了硬岩钻进时速度慢,刀具磨损大的问题.

  4. Bootstrap Dynamical Symmetry Breaking

    Directory of Open Access Journals (Sweden)

    Wei-Shu Hou

    2013-01-01

    Full Text Available Despite the emergence of a 125 GeV Higgs-like particle at the LHC, we explore the possibility of dynamical electroweak symmetry breaking by strong Yukawa coupling of very heavy new chiral quarks Q . Taking the 125 GeV object to be a dilaton with suppressed couplings, we note that the Goldstone bosons G exist as longitudinal modes V L of the weak bosons and would couple to Q with Yukawa coupling λ Q . With m Q ≳ 700  GeV from LHC, the strong λ Q ≳ 4 could lead to deeply bound Q Q ¯ states. We postulate that the leading “collapsed state,” the color-singlet (heavy isotriplet, pseudoscalar Q Q ¯ meson π 1 , is G itself, and a gap equation without Higgs is constructed. Dynamical symmetry breaking is affected via strong λ Q , generating m Q while self-consistently justifying treating G as massless in the loop, hence, “bootstrap,” Solving such a gap equation, we find that m Q should be several TeV, or λ Q ≳ 4 π , and would become much heavier if there is a light Higgs boson. For such heavy chiral quarks, we find analogy with the π − N system, by which we conjecture the possible annihilation phenomena of Q Q ¯ → n V L with high multiplicity, the search of which might be aided by Yukawa-bound Q Q ¯ resonances.

  5. Influencing Factors of Breaking Capacity of Double-Break Vacuum Circuit Breakers

    Directory of Open Access Journals (Sweden)

    Shengwen Shu

    2013-06-01

    Full Text Available Using a series arrangement of two vacuum interrupters (VIs has been proved to be an effective way of developing higher voltage vacuum circuit breakers (VCBs, which are known as double-break VCBs. The uniform distribution of the transient recovery voltage (TRV across each VI is very critical for the breaking capacity of double-break VCBs. In this paper, the TRV distribution characteristics of double-break VCBs was studied by the synthetic test and the PSCAD/EMTDC simulation based on a vacuum arc interruption model. The results show that the bias of the TRV distribution ratio is caused by the stray capacitance and the imbalanced post arc plasma characteristic in each VI, which is consistent with the theoretical analysis. Moreover, the negative effect of grading capacitors was discussed. The results show that it is advisable to limit the value of grading capacitors to those ranges which can guarantee sufficiently improve the voltage distribution.

  6. Detecting Structural Breaks using Hidden Markov Models

    DEFF Research Database (Denmark)

    Ntantamis, Christos

    Testing for structural breaks and identifying their location is essential for econometric modeling. In this paper, a Hidden Markov Model (HMM) approach is used in order to perform these tasks. Breaks are defined as the data points where the underlying Markov Chain switches from one state to another....... The estimation of the HMM is conducted using a variant of the Iterative Conditional Expectation-Generalized Mixture (ICE-GEMI) algorithm proposed by Delignon et al. (1997), that permits analysis of the conditional distributions of economic data and allows for different functional forms across regimes...

  7. La poetica degli spazi di Breaking Bad

    Directory of Open Access Journals (Sweden)

    Sara Martin

    2015-12-01

    Full Text Available Breaking Bad (2008-2013 produced, thanks to the creativity of Vince Gilligan and his writing room, some of the most emblematic characters in the history of contemporary television. Also, the writers of Breaking Bad were able to devise places and spaces that play important symbolic functions: spaces of mediation, spaces of transit, sacred spaces. This article investigates the meanings and characteristics of some of these settings: the swimming pool, the White family home, the meth lab. The analysis considers also the relation between characters and spaces, paying particular attention to the places inhabited by the main character, Walter White.

  8. Symmetry breaking. 2. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Strocchi, F. [Scuola Normale Superiore, Classe di Scienze, Pisa (Italy)

    2008-07-01

    This new edition of Prof. Strocchi's well received primer on rigorous aspects of symmetry breaking presents a more detailed and thorough discussion of the mechanism of symmetry breaking in classical field theory in relation with the Noether theorem. Moreover, the link between symmetry breaking without massless Goldstone bosons in Coulomb systems and in gauge theories is made more explicit in terms of the delocalized Coulomb dynamics. Furthermore, the chapter on the Higgs mechanism has been significantly expanded with a non-perturbative treatment of the Higgs phenomenon, at the basis of the standard model of particle physics, in the local and in the Coulomb gauges. Last but not least, a subject index has been added and a number of misprints have been corrected. From the reviews of the first edition: The notion of spontaneous symmetry breaking has proven extremely valuable, the problem is that most derivations are perturbative and heuristic. Yet mathematically precise versions do exist, but are not widely known. It is precisely the aim of his book to correct this unbalance. - It is remarkable to see how much material can actually be presented in a rigorous way (incidentally, many of the results presented are due to Strocchi himself), yet this is largely ignored, the original heuristic derivations being, as a rule, more popular. - At each step he strongly emphasizes the physical meaning and motivation of the various notions introduced, a book that fills a conspicuous gap in the literature, and does it rather well. It could also be a good basis for a graduate course in mathematical physics. It can be recommended to physicists as well and, of course, for physics/mathematics libraries. J.-P. Antoine, Physicalia 28/2, 2006 Strocchi's main emphasis is on the fact that the loss of symmetric behaviour requires both the non-symmetric ground states and the infinite extension of the system. It is written in a pleasant style at a level suitable for graduate students in

  9. Chiral symmetry and chiral-symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Peskin, M.E.

    1982-12-01

    These lectures concern the dynamics of fermions in strong interaction with gauge fields. Systems of fermions coupled by gauge forces have a very rich structure of global symmetries, which are called chiral symmetries. These lectures will focus on the realization of chiral symmetries and the causes and consequences of thier spontaneous breaking. A brief introduction to the basic formalism and concepts of chiral symmetry breaking is given, then some explicit calculations of chiral symmetry breaking in gauge theories are given, treating first parity-invariant and then chiral models. These calculations are meant to be illustrative rather than accurate; they make use of unjustified mathematical approximations which serve to make the physics more clear. Some formal constraints on chiral symmetry breaking are discussed which illuminate and extend the results of our more explicit analysis. Finally, a brief review of the phenomenological theory of chiral symmetry breaking is presented, and some applications of this theory to problems in weak-interaction physics are discussed. (WHK)

  10. Report of Break Out Group 1

    DEFF Research Database (Denmark)

    Alward, Randy; Carley, Kathleen M.; Madsen, Fredrik Huitfeldt

    2006-01-01

    To help understand a network and its ability to continue operating when under attack, the break out group discussed issues that need to be considered when presenting network vulnerability information to an analyst, manager or commander in effective support of that person's "observe, orient, decide......, action" (OODA) loop. The break out group discussed vulnerability presentation needs common across various application domains, particularly in support of network discovery and network analysis tasks in those domains. Finally, the break out group wished to determine whether there is a means...... of characterizing a vulnerability. This would take into account the potential for the vulnerability to be exploited as well as the potential impact on the operations supported by the network, and on the network structure itself, of a successful exploit of that vulnerability....

  11. Experimental Study on Coal-Breaking Pressure for Compressed Air

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on lab model experiments and through the limit analysis, the theoretical formula of calculauoncoal-breaking pressure with compressed air was derived. The experimental result shows that blasting pressure mustexceed 84.0 MPa to break coal with compressive strength of 13.2 MPa. The research provides an important theoretical basis for the design of airshooting mining and industrial tests.

  12. Corpuscular Breaking of Supersymmetry

    CERN Document Server

    Dvali, Gia

    2014-01-01

    Are topological solitons elementary or composites? We answer this question by drawing up a corpuscular formalism in which solitons are coherent states of quantum constituents. This naturally leads to a functional integral representation, in which the classical saddle point is reached as the most probable distribution of corpuscles in the $\\hbar = 0$ limit and where quantum corpuscular corrections correspond to excursions away from such a distribution that occur only for finite $\\hbar$. Several striking features come up. Topological charge emerges as a collective flow of quantum numbers carried by individual corpuscles. Moreover, the corpuscular corrections are not reducible to any known form of quantum corrections, such as loop expansions in the coupling constant $\\hbar g^2$ or semiclassical $e^{-1/\\hbar g^2}$ effects. Corpuscular corrections are stronger and appear already at order $\\sqrt{\\hbar g^2}$. In SUSY theories quantum corpuscular corrections generically break supersymmetry. We show that a domain wall...

  13. Break the Pattern!

    DEFF Research Database (Denmark)

    Hasse, Cathrine; Trentemøller, Stine

    Break the Pattern! A critical enquiry into three scientific workplace cultures: Hercules, Caretakers and Worker Bees is the third publication of the international three year long project "Understanding Puzzles in the Gendered European Map" (UPGEM). By contrasting empirical findings from academic...... workplaces in the five UPGEM-countries (Denmark, Estonia, Finland, Italy and Poland) we identify three clusters of cultural patterns in physics as culture. We call these Hercules, Caretakers and Worker Bees. We also consider the influence of national cultural historical processes on the scientific culture...... (physics in culture) and discuss how physics as and in culture influence the perception of science, of work and family life, of the interplay between religion and science as well as how physics as culture can either hinder or promote the career of female scientists....

  14. Dynamical (Super)Symmetry Breaking

    CERN Document Server

    Murayama, H

    2001-01-01

    Dynamical Symmetry Breaking (DSB) is a concept theorists rely on very often in the discussions of strong dynamics, model building, and hierarchy problems. In this talk, I will discuss why this is such a permeating concept among theorists and how they are used in understanding physics. I also briefly review recent progress in using dynamical symmetry breaking to construct models of supersymmetry breaking and fermion masses.

  15. Development of best estimate auditing code for CANDU thermal-hydraulic safety analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Bub Dong; Lee, Won Jae; Hwang, Moon Kyu; Lim, Hong Sik [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2002-04-01

    The main purpose of this study is to develop a thermal hydraulic auditing code for the CANDU reactor, modifying the model of existing PWR auditing tool, i.e. RELAP5/MOD3.The study was performed by reconsideration of the previous code assessment works and phenomena identification for essential accident scenario. Improvement areas of model development for auditing tool were identified based on the code comparison and PIRT results. Nine models have been improved significantly for the analysis of LOCA and Mon LOCA event. Conceptual problem or separate effect assessment have been performed to verify the model improvement. The linking calculation with CONTAIN 2.0 has been also enabled to establish the unified auditing code system. Analysis for the CANDU plant real transient and hypothetical LOCA bas been performed using the improved version. It has been concluded that the developed version can be utilized for the auditing analysis of LOCA and non-LOCA event for the CANDU reactor. 25 refs., 84 figs., 36 tabs. (Author)

  16. An Analysis of the Interactive Development between Lhasa and Shigatse from the Perspective of the Intensity of their Economic Contact and Regional Breaking Point

    Institute of Scientific and Technical Information of China (English)

    QIU Lilan

    2014-01-01

    In the Tibet Autonomous Region , Lhasa and Shigatse are the two core cities in the region’ s development , and they play a leading role for the development of other counties and cit-ies.From the perspective of research on urban ag-glomeration and urban geography , the two cities have a relationship of interactive contact and com-mon development .Within the context of rapid ur-banization in China , the interactive development between Lhasa and Shigatse has become an inevita-ble research focus for the socio-economic construc-tion of Tibet . The intensity of economic contact is used tomeasure the degree of regional economic ties.Onthe one hand, it can reflect the city’ s economiccenter ability to radiate out to the surrounding areas.On the other hand, it can also reflect the levelof acceptance of the surrounding areas to the city’s economic center ability to radiate out tothem.According to the results of economic calculation,the intensity of economic contact betweenLhasa and Shigatse from 2007 to 2011 steadily increasedwith an annual rate of about 20%.Thecontinuous increase of the intensity of economiccontact also meant that the influence of Lhasa andShigatse on the surrounding cities is expanding .Moreover, comparative data show that due to restrictionson the population and level of economicdevelopment, there is still a big gap in Lhasa andShigatse if compared with other urbanized areas inChina.However, regarding the increasing speedof the intensity of contact with other core cities,Lhasa and Shigatse have achieved remarkable a -chievements. During the 1930’ s, William J.Reilly proposedthe Law of Retail Gravitation which was usedby P.D.Converse in the field of urban managementto differentiate the scope of influence ofneighboring cities.In 1949, he put forward theconcept of “Breaking Point” together with a relevantcomputational formula.The Breaking Point isnormally determined by the scale of two cities andthe distance between them.According to the

  17. Electroweak breaking in supersymmetric models

    CERN Document Server

    Ibáñez, L E

    1992-01-01

    We discuss the mechanism for electroweak symmetry breaking in supersymmetric versions of the standard model. After briefly reviewing the possible sources of supersymmetry breaking, we show how the required pattern of symmetry breaking can automatically result from the structure of quantum corrections in the theory. We demonstrate that this radiative breaking mechanism works well for a heavy top quark and can be combined in unified versions of the theory with excellent predictions for the running couplings of the model. (To be published in ``Perspectives in Higgs Physics'', G. Kane editor.)

  18. High-Resolution Global Analysis of the Influences of Bas1 and Ino4 Transcription Factors on Meiotic DNA Break Distributions in Saccharomyces cerevisiae

    OpenAIRE

    Zhu, Xuan; Keeney, Scott

    2015-01-01

    Meiotic recombination initiates with DNA double-strand breaks (DSBs) made by Spo11. In Saccharomyces cerevisiae, many DSBs occur in “hotspots” coinciding with nucleosome-depleted gene promoters. Transcription factors (TFs) stimulate DSB formation in some hotspots, but TF roles are complex and variable between locations. Until now, available data for TF effects on global DSB patterns were of low spatial resolution and confined to a single TF. Here, we examine at high resolution the contributio...

  19. Locação social no Centro Histórico de Belém: investigação introdutória

    Directory of Open Access Journals (Sweden)

    Simaia do Socorro Sales das Mercês

    Full Text Available Neste artigo, busca-se iniciar discussão sobre a possibilidade de utilização da locação social como modalidade de provisão de moradia digna no Centro Histórico de Belém. Para isso: a analisa-se a locação social em políticas habitacionais brasileiras; b identifica-se e quantifica-se, para o Centro, a demanda potencial oriunda do déficit habitacional e a oferta potencial baseada nas hipóteses de adaptação de imóveis desocupados e subutilizados e de construção de unidades habitacionais em lotes vazios e com ruínas. O estudo conclui que há, em princípio, oferta suficiente para atender à demanda do Centro e de outras áreas da cidade. Entretanto, ressalta que para a efetivação dessa oferta, é necessário superar vários entraves. Por fim, alerta que o aluguel social em centros históricos, além de política de provisão de moradia, configura uma política de conservação do patrimônio histórico e cultural, o que agrega benefícios a serem contabilizados como resultado da política proposta.

  20. Aging of electrical components in nuclear power plants. Relationships between mechanical and chemical degradation after artificial aging and dielectric behaviour during LOCA

    Energy Technology Data Exchange (ETDEWEB)

    Spaang, K. [Ingemansson Tchnology AB, Goeteborg (Sweden)

    1997-10-01

    This study includes: (A) Extended thermal aging at 120 and 142 deg C. (B) LOCA testing on a selection of components which were aged in an earlier test. The cables included Lipalon type FSSR7x1, Daetwyler type FEAR-PG 8x(2x1) and Rockbestos Firewall 3, RXSR-G 5x1. The o-rings included two types, Viton and EPDM. Both had a diameter of 37,47 mm and a thickness of 5,34 mm. Coils of solenoids type Seitz 2A25, 110 VDC were used in some of the tests. Thermal aging was performed in dry heat test chambers, fulfilling the requirements for testing according to IEC Publ 68-2-2, test Bb: Dry heat testing of non heat-dissipating specimen. The irradiation test used a dose rate 10 kGy/h for 50 h. The measurement during LOCA testing included insulation resistance and dielectric loss factor. 4 refs, 48 figs, 42 tabs.

  1. On partially entanglement breaking channels

    CERN Document Server

    Chruscinski, D; Chruscinski, Dariusz; Kossakowski, Andrzej

    2005-01-01

    Using well known duality between quantum maps and states of composite systems we introduce the notion of Schmidt number of a quantum channel. It enables one to define classes of quantum channels which partially break quantum entanglement. These classes generalize the well known class of entanglement breaking channels.

  2. Entanglement–breaking indices

    Energy Technology Data Exchange (ETDEWEB)

    Lami, L. [Scuola Normale Superiore, I-56126 Pisa (Italy); Giovannetti, V. [NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, I-56127 Pisa (Italy)

    2015-09-15

    We study a set of new functionals (called entanglement–breaking indices) which characterize how many local iterations of a given (local) quantum channel are needed in order to completely destroy the entanglement between the system of interest over which the transformation is defined and an external ancilla. The possibility of contrasting the noisy effects introduced by the channel iterations via the action of intermediate (filtering) transformations is analyzed. We provide some examples in which our functionals can be exactly calculated. The differences between unitary and non-unitary filtering operations are analyzed showing that, at least for systems of dimension d larger than or equal to 3, the non-unitary choice is preferable (the gap between the performances of the two cases being divergent in some cases). For d = 2 (qubit case), on the contrary, no evidences of the presence of such gap is revealed: we conjecture that for this special case unitary filtering transformations are optimal. The scenario in which more general filtering protocols are allowed is also discussed in some detail. The case of a depolarizing noise acting on a two–qubit system is exactly solved in a general case.

  3. Proton-Induced X-ray Emission (PIXE) Analysis and DNA-chain Break study in rat hepatocarcinogenesis: A possible chemopreventive role by combined supplementation of vanadium and beta-carotene

    OpenAIRE

    2005-01-01

    Abstract Combined effect of vanadium and beta-carotene on rat liver DNA-chain break and Proton induced X-ray emission (PIXE) analysis was studied during a necrogenic dose (200 mg/kg of body weight) of Diethyl Nitrosamine (DENA) induced rat liver carcinogenesis. Morphological and histopathological changes were observed as an end point biomarker. Supplementation of vanadium (0.5 ppm ad libitum) in drinking water and beta-carotene in the basal diet (120 mg/Kg of body weight) were performed four ...

  4. 天堂山水库溃坝风险分析%Risk Analysis on the Dam Break of Tian-Tang Mountain Reservoir

    Institute of Scientific and Technical Information of China (English)

    廖云雀; 李志菲

    2014-01-01

    According to the dam break accidents that caused by possible emergencies , and in accordance with the relevant litera-ture, when dam breaks the four parameters is calculated as follows:the dam site maximum flow, the maximum flow of each control section of the river, flood travel time, flooding height and flooding range .On this basis, the loss caused by dam failure is assessed;the event level in conformity to the criteria crisis classification is determined .%根据天堂山水库可能出现的突发事件造成溃坝事件发生,按有关文献计算溃坝时坝址最大流量,以及河道各控制断面的最大流量、洪水传播时间、淹浸高度、淹浸范围等,评估溃坝事件造成的损失,按突发事件分级评定标准确定事件等级。

  5. ANALISA BREAK EVENT POINT (BEP TERHADAP LABA PERUSAHAAN

    Directory of Open Access Journals (Sweden)

    Muhammad Yusuf

    2015-09-01

    Full Text Available Break event point or the break-even point can be defined as a situation where the operating company does not make a profit and not a loss. The goal is to provide the knowledge to increase knowledge about the break event point (the point of principal and its relationship with the company profit and to know how the results of the. Analysis break event point is very important for the leadership of the company to determine the production rate how much the cost will be equal to the amount of sales or in other words to determine the break event point we will determine the relationship between sales, production, selling price, cost, loss or profit, making it easier for leaders to take discretion.DOI: 10.15408/ess.v4i1.1955 

  6. Experimental assessment of computer codes used for safety analysis of integral reactors

    Energy Technology Data Exchange (ETDEWEB)

    Falkov, A.A.; Kuul, V.S.; Samoilov, O.B. [OKB Mechanical Engineering, Nizhny Novgorod (Russian Federation)

    1995-09-01

    Peculiarities of integral reactor thermohydraulics in accidents are associated with presence of noncondensable gas in built-in pressurizer, absence of pumped ECCS, use of guard vessel for LOCAs localisation and passive RHRS through in-reactor HX`s. These features defined the main trends in experimental investigations and verification efforts for computer codes applied. The paper reviews briefly the performed experimental investigation of thermohydraulics of AST-500, VPBER600-type integral reactors. The characteristic of UROVEN/MB-3 code for LOCAs analysis in integral reactors and results of its verification are given. The assessment of RELAP5/mod3 applicability for accident analysis in integral reactor is presented.

  7. Calculation of Departure from Nucleate Boiling Ratio (DNBR) minimum for accident analysis of main steam line break at Angra-1; Calculo do minimo DNBR para analise do acidente de ruptura da linha principal de vapor em Angra-1

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Marcio Dornellas [ELETROBRAS Termonuclear S.A. (ELETRONUCLEAR), Rio de Janeiro, RJ (Brazil). E-mail: mdorne@eletronuclear.gov.br

    2000-07-01

    The maintenance costs, the operational problems and the failures possibilities of the boron injection system, composed by pumps, valves, heated lines and the boron injection tank, make this tank removal or the boron concentration reduction advisable for Angra 1 Power Plant. The main accident from chapter XV of the final safety analysis report affected by this modification is the main steam line break. It is necessary the interaction of the areas of Accidents and Transients Analysis (RETRAN 02/Mod 5.1 code), Neutronics (APA System) and Thermohydraulics (COBRA IIIC/MIT) to analyse this accident. The present Angra 1 boron concentration is 20000 ppm and it could be reduced to 2000 ppm as a result of the present study. The Departure from Nucleate Boiling Ratio (DNBR) is the restrictive parameter of this accident, which is calculated from the initials and boundary conditions obtained from the Transients and Accidents Analysis and Neutronics areas. (author)

  8. Breaking beer bottles with cavitation

    Science.gov (United States)

    Jung, Sunny; Fontana, Jake; Palffy-Muhoray, Peter; Shelley, Michael

    2009-03-01

    Hitting the top of a beer bottle, nearly full of water, with an open hand can cause the bottle to break, with the bottom separating from upper section. We have studied this phenomenon using a high-speed camera, and observed the formation, coalescence and collapse of bubbles. The breaking of glass is due to cavitation, typically occurring near the bottom edge. We make numerical estimates of the relevant physical parameters, and compare these with experimental observations.

  9. Analysis of Repair Mechanisms following an Induced Double-Strand Break Uncovers Recessive Deleterious Alleles in the Candida albicans Diploid Genome

    Science.gov (United States)

    Feri, Adeline; Loll-Krippleber, Raphaël; Commere, Pierre-Henri; Maufrais, Corinne; Sertour, Natacha; Schwartz, Katja; Sherlock, Gavin; Bougnoux, Marie-Elisabeth

    2016-01-01

    ABSTRACT The diploid genome of the yeast Candida albicans is highly plastic, exhibiting frequent loss-of-heterozygosity (LOH) events. To provide a deeper understanding of the mechanisms leading to LOH, we investigated the repair of a unique DNA double-strand break (DSB) in the laboratory C. albicans SC5314 strain using the I-SceI meganuclease. Upon I-SceI induction, we detected a strong increase in the frequency of LOH events at an I-SceI target locus positioned on chromosome 4 (Chr4), including events spreading from this locus to the proximal telomere. Characterization of the repair events by single nucleotide polymorphism (SNP) typing and whole-genome sequencing revealed a predominance of gene conversions, but we also observed mitotic crossover or break-induced replication events, as well as combinations of independent events. Importantly, progeny that had undergone homozygosis of part or all of Chr4 haplotype B (Chr4B) were inviable. Mining of genome sequencing data for 155 C. albicans isolates allowed the identification of a recessive lethal allele in the GPI16 gene on Chr4B unique to C. albicans strain SC5314 which is responsible for this inviability. Additional recessive lethal or deleterious alleles were identified in the genomes of strain SC5314 and two clinical isolates. Our results demonstrate that recessive lethal alleles in the genomes of C. albicans isolates prevent the occurrence of specific extended LOH events. While these and other recessive lethal and deleterious alleles are likely to accumulate in C. albicans due to clonal reproduction, their occurrence may in turn promote the maintenance of corresponding nondeleterious alleles and, consequently, heterozygosity in the C. albicans species. PMID:27729506

  10. Analysis of Repair Mechanisms following an Induced Double-Strand Break Uncovers Recessive Deleterious Alleles in the Candida albicans Diploid Genome.

    Science.gov (United States)

    Feri, Adeline; Loll-Krippleber, Raphaël; Commere, Pierre-Henri; Maufrais, Corinne; Sertour, Natacha; Schwartz, Katja; Sherlock, Gavin; Bougnoux, Marie-Elisabeth; d'Enfert, Christophe; Legrand, Mélanie

    2016-10-11

    The diploid genome of the yeast Candida albicans is highly plastic, exhibiting frequent loss-of-heterozygosity (LOH) events. To provide a deeper understanding of the mechanisms leading to LOH, we investigated the repair of a unique DNA double-strand break (DSB) in the laboratory C. albicans SC5314 strain using the I-SceI meganuclease. Upon I-SceI induction, we detected a strong increase in the frequency of LOH events at an I-SceI target locus positioned on chromosome 4 (Chr4), including events spreading from this locus to the proximal telomere. Characterization of the repair events by single nucleotide polymorphism (SNP) typing and whole-genome sequencing revealed a predominance of gene conversions, but we also observed mitotic crossover or break-induced replication events, as well as combinations of independent events. Importantly, progeny that had undergone homozygosis of part or all of Chr4 haplotype B (Chr4B) were inviable. Mining of genome sequencing data for 155 C. albicans isolates allowed the identification of a recessive lethal allele in the GPI16 gene on Chr4B unique to C. albicans strain SC5314 which is responsible for this inviability. Additional recessive lethal or deleterious alleles were identified in the genomes of strain SC5314 and two clinical isolates. Our results demonstrate that recessive lethal alleles in the genomes of C. albicans isolates prevent the occurrence of specific extended LOH events. While these and other recessive lethal and deleterious alleles are likely to accumulate in C. albicans due to clonal reproduction, their occurrence may in turn promote the maintenance of corresponding nondeleterious alleles and, consequently, heterozygosity in the C. albicans species.

  11. Analysis of Repair Mechanisms following an Induced Double-Strand Break Uncovers Recessive Deleterious Alleles in the Candida albicans Diploid Genome

    Directory of Open Access Journals (Sweden)

    Adeline Feri

    2016-10-01

    Full Text Available The diploid genome of the yeast Candida albicans is highly plastic, exhibiting frequent loss-of-heterozygosity (LOH events. To provide a deeper understanding of the mechanisms leading to LOH, we investigated the repair of a unique DNA double-strand break (DSB in the laboratory C. albicans SC5314 strain using the I-SceI meganuclease. Upon I-SceI induction, we detected a strong increase in the frequency of LOH events at an I-SceI target locus positioned on chromosome 4 (Chr4, including events spreading from this locus to the proximal telomere. Characterization of the repair events by single nucleotide polymorphism (SNP typing and whole-genome sequencing revealed a predominance of gene conversions, but we also observed mitotic crossover or break-induced replication events, as well as combinations of independent events. Importantly, progeny that had undergone homozygosis of part or all of Chr4 haplotype B (Chr4B were inviable. Mining of genome sequencing data for 155 C. albicans isolates allowed the identification of a recessive lethal allele in the GPI16 gene on Chr4B unique to C. albicans strain SC5314 which is responsible for this inviability. Additional recessive lethal or deleterious alleles were identified in the genomes of strain SC5314 and two clinical isolates. Our results demonstrate that recessive lethal alleles in the genomes of C. albicans isolates prevent the occurrence of specific extended LOH events. While these and other recessive lethal and deleterious alleles are likely to accumulate in C. albicans due to clonal reproduction, their occurrence may in turn promote the maintenance of corresponding nondeleterious alleles and, consequently, heterozygosity in the C. albicans species.

  12. More than a break

    DEFF Research Database (Denmark)

    Villadsen, Katrine Weiersoe; Blix, Charlotte; Boisen, Kirsten A

    2015-01-01

    analysis, the following themes emerged: Recreation; Structure, participation, and motivation; and Friends and social network. The social-pedagogical approach is a combination of interpersonal relationships and individually tailored recreational activities. Even small entertaining activities changed...

  13. Visualization of cabin radioactivity in unisolated small LOCA of small reactor%小型堆不可隔离小破口事故下的舱室放射性活度可视化

    Institute of Scientific and Technical Information of China (English)

    晏峰; 张帆; 陈力生; 张彦招

    2015-01-01

    The MELCOR program,is used to establish an accident analysis model for a ship′s pressu-rized water reactor.An investigation is conducted into the changes of cabin radioactivity in the case of a severe accident induced by the small LOCA which cannot be isolated from the power failure in the ship.The results show that if the safety measures are invalid,the core will be melted due to this acci-dent.The radioactivity of the reactor cabin is 4 orders of magnitude higher than that of the adjacent cabin.For this reason,the visualization system of the radiation field of small reactor is developed with regard to a typical serious accident.The system can provide support for the assessment of cabin dose and the nuclear emergency decision-making.%以某小型压水堆为研究对象,运用 MELCOR 程序建立事故分析模型,研究了不可隔离小破口合并全船断电始发严重事故下舱室放射性活度变化规律。结果表明:不可隔离小破口事故下,倘若安全设施失效,将导致堆芯熔化;堆舱放射性活度比其相邻舱室高4个量级。在此基础上,开发了小型堆典型严重事故下辐射场可视化系统,可为舱室剂量评估和核应急决策提供支持。

  14. Symmetry-breaking oscillations in membrane optomechanics

    Science.gov (United States)

    Wurl, C.; Alvermann, A.; Fehske, H.

    2016-12-01

    We study the classical dynamics of a membrane inside a cavity in the situation where this optomechanical system possesses a reflection symmetry. Symmetry breaking occurs through supercritical and subcritical pitchfork bifurcations of the static fixed-point solutions. Both bifurcations can be observed through variation of the laser-cavity detuning, which gives rise to a boomerang-like fixed-point pattern with hysteresis. The symmetry-breaking fixed points evolve into self-sustained oscillations when the laser intensity is increased. In addition to the analysis of the accompanying Hopf bifurcations we describe these oscillations at finite amplitudes with an ansatz that fully accounts for the frequency shift relative to the natural membrane frequency. We complete our study by following the route to chaos for the membrane dynamics.

  15. An automatic system for elaboration of chip breaking diagrams

    DEFF Research Database (Denmark)

    Andreasen, Jan Lasson; De Chiffre, Leonardo

    1998-01-01

    A laboratory system for fully automatic elaboration of chip breaking diagrams has been developed and tested. The system is based on automatic chip breaking detection by frequency analysis of cutting forces in connection with programming of a CNC-lathe to scan different feeds, speeds and cutting...... depths. An evaluation of the system based on a total of 1671 experiments has shown that unfavourable snarled chips can be detected with 98% certainty which indeed makes the system a valuable tool in chip breakability tests. Using the system, chip breaking diagrams can be elaborated with a previously...

  16. Proton-Induced X-ray Emission (PIXE Analysis and DNA-chain Break study in rat hepatocarcinogenesis: A possible chemopreventive role by combined supplementation of vanadium and beta-carotene

    Directory of Open Access Journals (Sweden)

    Kanjilal NB

    2005-05-01

    Full Text Available Abstract Combined effect of vanadium and beta-carotene on rat liver DNA-chain break and Proton induced X-ray emission (PIXE analysis was studied during a necrogenic dose (200 mg/kg of body weight of Diethyl Nitrosamine (DENA induced rat liver carcinogenesis. Morphological and histopathological changes were observed as an end point biomarker. Supplementation of vanadium (0.5 ppm ad libitum in drinking water and beta-carotene in the basal diet (120 mg/Kg of body weight were performed four weeks before DENA treatment and continued till the end of the experiment (16 weeks. PIXE analysis revealed the restoration of near normal value of zinc, copper, and iron, which were substantially altered when compared to carcinogen treated groups. Supplementation of both vanadium and beta-carotene four weeks before DENA injection was found to offer significant (64.73%, P

  17. On the Application of Fishbone Diagram Analysis in Tailings Reservoir Dam Break%鱼刺图评价法在尾矿库溃坝事故中的应用

    Institute of Scientific and Technical Information of China (English)

    吴令; 周波

    2012-01-01

    根据尾矿库现场危险、有害因素辨识结果,概括出尾矿库溃坝事故发主的四个主要因素:施工、排洪、渗流和管理,对主要因素的原因进行归纳、分析,找出了重要原因,应用鱼刺图法评价得到了尾矿库溃坝事故的危险程度和等级,提出了防止这类事故发生的重点安全对策措施,提高了尾矿库的安全管理程度.%According to the identification results of dangerous and harmful factors identification in the tailings reservoir site, the four main factors: construction, drainage flood, seepage flow and management are summarized in the dam-break accident. Through induction and analysis, found out the main reasons. The risk degree and level of the tailings dam-break accident are got by using the fishbone diagram, and some safety measures are put forward. Tailing dam safety management level has been improved.

  18. Identification and Analysis of MS5(d): A Gene That Affects Double-Strand Break (DSB) Repair during Meiosis I in Brassica napus Microsporocytes.

    Science.gov (United States)

    Zeng, Xinhua; Yan, Xiaohong; Yuan, Rong; Li, Keqi; Wu, Yuhua; Liu, Fang; Luo, Junling; Li, Jun; Wu, Gang

    2016-01-01

    Here, we report the identification of the Brassica-specific gene MS5(d), which is responsible for male sterility in Brassica napus. The MS5(d) gene is highly expressed in the microsporocyte and encodes a protein that localizes to the nucleus. Light microscopy analyses have demonstrated that the MS5(d) gene affects microsporocyte meiosis in the thermosensitive genic male sterility line TE5A. Sequence comparisons and genetic complementation revealed a C-to-T transition in MS5(d), encoding a Leu-to-Phe (L281F) substitution and causing abnormal male meiosis in TE5A. These findings suggest arrested meiotic chromosome dynamics at pachytene. Furthermore, immunofluorescence analyses showed that double-strand break (DSB) formation and axial elements were normal but that DSB repair and spindle behavior were aberrant in TE5A meiocytes. Collectively, our results indicate that MS5(d) likely encodes a protein required for chromosomal DSB repair at early stages of meiosis in B. napus.

  19. Application of CFD Codes in Nuclear Reactor Safety Analysis

    Directory of Open Access Journals (Sweden)

    T. Höhne

    2010-01-01

    Full Text Available Computational Fluid Dynamics (CFD is increasingly being used in nuclear reactor safety (NRS analyses as a tool that enables safety relevant phenomena occurring in the reactor coolant system to be described in more detail. Numerical investigations on single phase coolant mixing in Pressurised Water Reactors (PWR have been performed at the FZD for almost a decade. The work is aimed at describing the mixing phenomena relevant for both safety analysis, particularly in steam line break and boron dilution scenarios, and mixing phenomena of interest for economical operation and the structural integrity. For the experimental investigation of horizontal two phase flows, different non pressurized channels and the TOPFLOW Hot Leg model in a pressure chamber was build and simulated with ANSYS CFX. In a common project between the University of Applied Sciences Zittau/Görlitz and FZD the behaviour of insulation material released by a LOCA released into the containment and might compromise the long term emergency cooling systems is investigated. Moreover, the actual capability of CFD is shown to contribute to fuel rod bundle design with a good CHF performance.

  20. High-Resolution Global Analysis of the Influences of Bas1 and Ino4 Transcription Factors on Meiotic DNA Break Distributions in Saccharomyces cerevisiae.

    Science.gov (United States)

    Zhu, Xuan; Keeney, Scott

    2015-10-01

    Meiotic recombination initiates with DNA double-strand breaks (DSBs) made by Spo11. In Saccharomyces cerevisiae, many DSBs occur in "hotspots" coinciding with nucleosome-depleted gene promoters. Transcription factors (TFs) stimulate DSB formation in some hotspots, but TF roles are complex and variable between locations. Until now, available data for TF effects on global DSB patterns were of low spatial resolution and confined to a single TF. Here, we examine at high resolution the contributions of two TFs to genome-wide DSB distributions: Bas1, which was known to regulate DSB activity at some loci, and Ino4, for which some binding sites were known to be within strong DSB hotspots. We examined fine-scale DSB distributions in TF mutant strains by deep sequencing oligonucleotides that remain covalently bound to Spo11 as a byproduct of DSB formation, mapped Bas1 and Ino4 binding sites in meiotic cells, evaluated chromatin structure around DSB hotspots, and measured changes in global messenger RNA levels. Our findings show that binding of these TFs has essentially no predictive power for DSB hotspot activity and definitively support the hypothesis that TF control of DSB numbers is context dependent and frequently indirect. TFs often affected the fine-scale distributions of DSBs within hotspots, and when seen, these effects paralleled effects on local chromatin structure. In contrast, changes in DSB frequencies in hotspots did not correlate with quantitative measures of chromatin accessibility, histone H3 lysine 4 trimethylation, or transcript levels. We also ruled out hotspot competition as a major source of indirect TF effects on DSB distributions. Thus, counter to prevailing models, roles of these TFs on DSB hotspot strength cannot be simply explained via chromatin "openness," histone modification, or compensatory interactions between adjacent hotspots.

  1. Grapevine bud break prediction for cool winter climates

    Science.gov (United States)

    Nendel, Claas

    2010-05-01

    Statistical analysis of bud break data for grapevine ( Vitis vinifera L. cvs. Riesling and Müller-Thurgau) at 13 sites along the northern boundary of commercial grapevine production in Europe revealed that, for all investigated sites, the heat summation method for bud break prediction can be improved if the starting date for the accumulation of heat units is specifically determined. Using the coefficient of variance as a criterion, a global minimum for each site can be identified, marking the optimum starting date. Furthermore, it was shown that the application of a threshold temperature for the heat summation method does not lead to an improved prediction of bud break. Using site-specific parameters, bud break of grapevine can be predicted with an accuracy of ± 2.5 days. Using average parameters, the prediction accuracy is reduced to ± 4.5 days, highlighting the sensitivity of the heat summation method to the quality and the representativeness of the driving temperature data.

  2. Development of RBMK-1500 Model for BDBA Analysis Using RELAP/SCDAPSIM Code

    Science.gov (United States)

    Uspuras, Eugenijus; Kaliatka, Algirdas

    This article discusses the specificity of RBMK (channel type, boiling water, graphite moderated) reactors and problems of Reactor Cooling System modelling employing computer codes. The article presents, how the RELAP/SCDAPSIM code, which is originally designed for modelling of accidents in vessel type reactors, is fit to simulate the phenomena in the RBMK reactor core and RCS in case of Beyond Design Basis Accidents. For this reason, use of two RELAP/SCDAPSIM models is recommended. First model with described complete geometry of RCS is recommended for analysis of initial phase of accident. The calculations results, received using this model, are used as boundary conditions in simplified model for simulation of later phases of severe accidents. The simplified model was tested comparing results of simulation performed using RELAP5 and RELAP/SCDAPSIM codes. As the typical example of BDBA, large break LOCA in reactor cooling system with failure of emergency core cooling system was analyzed. Use of developed models allows to receive behaviour of thermal-hydraulic parameters, temperatures of core components, amount of generated hydrogen due to steam-zirconium reaction. These parameters will be used as input for other special codes, designed for analysis of processes in reactor containment.

  3. Hole localization and symmetry breaking

    NARCIS (Netherlands)

    Broer, R; Nieuwpoort, W.C.

    1999-01-01

    A brief overview is presented of some theoretical work on the symmetry breaking of electronic wavefunctions that followed the early work on Bagus and Schaefer who observed that a considerable lower SCF energy could be obtained for an ionized state of the O2 molecule with a 1s hole if the symmetry re

  4. Appointment breaking: causes and solutions.

    Science.gov (United States)

    Bean, A G; Talaga, J

    1992-12-01

    From a review of research on health care appointment breaking, the authors find that patient demographic characteristics, psychosocial problems, previous appointment keeping, health beliefs, and situational factors predict no-show behavior. Suggestions are offered for designing the marketing mix to increase patient appointment keeping. Methods for mitigating the negative effects of no-shows on health care providers are described.

  5. Code breaking in the pacific

    CERN Document Server

    Donovan, Peter

    2014-01-01

    Covers the historical context and the evolution of the technically complex Allied Signals Intelligence (Sigint) activity against Japan from 1920 to 1945 Describes, explains and analyzes the code breaking techniques developed during the war in the Pacific Exposes the blunders (in code construction and use) made by the Japanese Navy that led to significant US Naval victories

  6. Inflationary implications of supersymmetry breaking

    NARCIS (Netherlands)

    Borghese, Andrea; Roest, Diederik; Zavala, Ivonne

    2013-01-01

    We discuss a general bound on the possibility to realise inflation in any minimal supergravity with F-terms. The derivation crucially depends on the sGoldstini, the scalar field directions that are singled out by spontaneous supersymmetry breaking. The resulting bound involves both slow-roll paramet

  7. Breaking Carbon Lock-in

    DEFF Research Database (Denmark)

    Driscoll, Patrick Arthur

    2014-01-01

    This central focus of this paper is to highlight the ways in which path dependencies and increasing returns (network effects) serve to reinforce carbon lock-in in large-scale road transportation infrastructure projects. Breaking carbon lock-in requires drastic changes in the way we plan future...

  8. Strong coupling electroweak symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Barklow, T.L. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Burdman, G. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Physics; Chivukula, R.S. [Boston Univ., MA (United States). Dept. of Physics

    1997-04-01

    The authors review models of electroweak symmetry breaking due to new strong interactions at the TeV energy scale and discuss the prospects for their experimental tests. They emphasize the direct observation of the new interactions through high-energy scattering of vector bosons. They also discuss indirect probes of the new interactions and exotic particles predicted by specific theoretical models.

  9. Small Break Air Ingress Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Chang Oh; Eung Soo Kim

    2011-09-01

    The small break air-ingress experiment, described in this report, is designed to investigate air-ingress phenomena postulated to occur in pipes in a very high temperature gas-cooled reactor (VHTRs). During this experiment, air-ingress rates were measured for various flow and break conditions through small holes drilled into a pipe of the experimental apparatus. The holes were drilled at right angles to the pipe wall such that a direction vector drawn from the pipe centerline to the center of each hole was at right angles with respect to the pipe centerline. Thus the orientation of each hole was obtained by measuring the included angle between the direction vector of each hole with respect to a reference line anchored on the pipe centerline and pointing in the direction of the gravitational force. Using this reference system, the influence of several important parameters on the air ingress flow rate were measured including break orientation, break size, and flow velocity . The approach used to study the influence of these parameters on air ingress is based on measuring the changes in oxygen concentrations at various locations in the helium flow circulation system as a function of time using oxygen sensors (or detectors) to estimate the air-ingress rates through the holes. The test-section is constructed of a stainless steel pipe which had small holes drilled at the desired locations.

  10. Aluminum break-point contacts

    NARCIS (Netherlands)

    Heinemann, Martina; Groot, R.A. de

    1997-01-01

    Ab initio molecular dynamics is used to study the contribution of a single Al atom to an aluminum breakpoint contact during the final stages of breaking and the initial stages of the formation of such a contact. A hysteresis effect is found in excellent agreement with experiment and the form of the

  11. How do accretion discs break?

    Science.gov (United States)

    Dogan, Suzan

    2016-07-01

    Accretion discs are common in binary systems, and they are often found to be misaligned with respect to the binary orbit. The gravitational torque from a companion induces nodal precession in misaligned disc orbits. In this study, we first calculate whether this precession is strong enough to overcome the internal disc torques communicating angular momentum. We compare the disc precession torque with the disc viscous torque to determine whether the disc should warp or break. For typical parameters precession wins: the disc breaks into distinct planes that precess effectively independently. To check our analytical findings, we perform 3D hydrodynamical numerical simulations using the PHANTOM smoothed particle hydrodynamics code, and confirm that disc breaking is widespread and enhances accretion on to the central object. For some inclinations, the disc goes through strong Kozai cycles. Disc breaking promotes markedly enhanced and variable accretion and potentially produces high-energy particles or radiation through shocks. This would have significant implications for all binary systems: e.g. accretion outbursts in X-ray binaries and fuelling supermassive black hole (SMBH) binaries. The behaviour we have discussed in this work is relevant to a variety of astrophysical systems, for example X-ray binaries, where the disc plane may be tilted by radiation warping, SMBH binaries, where accretion of misaligned gas can create effectively random inclinations and protostellar binaries, where a disc may be misaligned by a variety of effects such as binary capture/exchange, accretion after binary formation.

  12. Chiral symmetry breaking in continuum QCD

    Science.gov (United States)

    Mitter, Mario; Pawlowski, Jan M.; Strodthoff, Nils

    2015-03-01

    We present a quantitative analysis of chiral symmetry breaking in two-flavor continuum QCD in the quenched limit. The theory is set up at perturbative momenta, where asymptotic freedom leads to precise results. The evolution of QCD towards the hadronic phase is achieved by means of dynamical hadronization in the nonperturbative functional renormalization group approach. We use a vertex expansion scheme based on gauge-invariant operators and discuss its convergence properties and the remaining systematic errors. In particular, we present results for the quark propagator, the full tensor structure and momentum dependence of the quark-gluon vertex, and the four-Fermi scatterings.

  13. Simulation of A Main Steam Line Break Accident Using the Coupled 'System Thermal-Hydraulics, 3D reactor Kinetics, and Hot Channel' Analysis Capability of MARS 3.0

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Jae Jun; Chung, Bub Dong

    2005-09-15

    For realistic analysis of thermal-hydraulics (T-H) transients in light water reactors, KAERI has developed the best-estimate T-H system code, MARS. The code has been improved from the consolidated version of the RELAP5/MOD3 and COBRA-TF codes. Then, the MARS code was coupled with a three-dimensional (3-D) reactor kinetics code, MASTER. This coupled calculation feature, in conjunction with the existing hot channel analysis capabilities of the MARS and MASTER codes, allows for more realistic simulations of nuclear system transients. In this work, a main steam line break (MSLB) accident is simulated using the coupled 'system T-H, 3-D reactor kinetics, and hot channel analysis' feature of the MARS code. Two coupled calculations are performed for demonstration. First, a coupled calculation of the 'system T-H and 3-D reactor kinetics' with a refined core T-H nodalization is carried out to obtain global core power and local departure from nucleate boiling (DNB) ratio (DNBR) behaviors. Next, for a more accurate DNBR prediction, another coupled calculation with subchannel meshes for the hot channels is performed. The results of the coupled calculations are very reasonable and consistent so that these can be used to remove the excessive conservatism in the conventional safety analysis.

  14. 澳洲坚果破壳工艺参数优化及压缩特性的有限元分析%Optimization of technical parameters of breaking Macadamia nut shell and finite element analysis of compression characteristics

    Institute of Scientific and Technical Information of China (English)

    涂灿; 杨薇; 尹青剑; 吕俊龙

    2015-01-01

    sphere. The width diameter was near to average diameter of macadamia nut. The thickness was 4.03-4.36 mm at top of macadamia nut and 2.22-2.48 mm at the middle. That showed that the shell thickness of macadamia nut was nonuniform. The shell’s material was similar to wood, so poisson’s ratio was near to 0.3. Material properties and geometric model of macadamia nut were imported into ANSYS workbench. The distribution of stress and strain of breaking shell of macadamia nut was obtained by finite element analysis of macadamia nut. According to the finite element analysis diagram of macadamia nuts in the 3 loading directions, it could be known that cracks were easy to emerge and expand in horizontal. It was also horizontal which was the most appropriate for breaking macadamia nut shell. The simulation results were consistent with the results of experiment. The biggest shelled force was 2016 N in horizontal, and therefore the shelled force should not be less than 2500 N for ensuring that all nuts would be cracked. The loaded force should be in horizontal when macadamia nut shell was crushed. It provides the design basis for the macadamia nut shell-breaking machine.%为了提高澳洲坚果破壳整仁率,该文首先以加载速度、加载方向、果壳含水率为试验因素进行正交试验,以破壳后澳洲坚果果仁的整仁率为评价指标,优化出适宜澳洲坚果破壳的最佳工艺参数为:加载速率45 mm/min、沿水平向加载、果壳含水率6%~9%。在此破壳工艺下进行试验,得出澳洲坚果的整仁率最高可达93%。澳洲坚果果壳种脐向、宽度向、水平向的平均破壳力分别为1018、2274、1173 N;弹性模量分别为32.24、68.63、39.65 MPa。说明澳洲坚果是各向异性的,宽度向的抗压能力最强。运用有限元方法对澳洲坚果的3个加载方向进行应力和应变分析,得出较佳的施力方向为水平向,与试验结果一致。故在设计破壳机时,施加于

  15. Breaking Wave Characteristics and Breaking Wave Forces on Slender Cylinders

    OpenAIRE

    Chella, Mayilvahanan Alagan

    2016-01-01

    Offshore wind farms have become an increasingly important source of clean and renewable energy. Most recent offshore wind farms are deployed close to the coast in shallow waters. One of the major factors influencing the initial investment of this technology is the design of the substructure and foundation. The physical processes associated with the non-linear shallow water hydrodynamics are rather complex since the wave motion is strongly influenced by the seabed. Breaking wave...

  16. A model of intrinsic symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Li [Research Center for Quantum Manipulation, Department of Physics, Fudan University, Shanghai 200433 (China); Li, Sheng [Department of Physics, Zhejiang Normal University, Zhejiang 310004 (China); George, Thomas F., E-mail: tfgeorge@umsl.edu [Office of the Chancellor and Center for Nanoscience, Department of Chemistry and Biochemistry, University of Missouri-St. Louis, St. Louis, MO 63121 (United States); Department of Physics and Astronomy, University of Missouri-St. Louis, St. Louis, MO 63121 (United States); Sun, Xin, E-mail: xin_sun@fudan.edu.cn [Research Center for Quantum Manipulation, Department of Physics, Fudan University, Shanghai 200433 (China)

    2013-11-01

    Different from the symmetry breaking associated with a phase transition, which occurs when the controlling parameter is manipulated across a critical point, the symmetry breaking presented in this Letter does not need parameter manipulation. Instead, the system itself suddenly undergoes symmetry breaking at a certain time during its evolution, which is intrinsic symmetry breaking. Through a polymer model, it is revealed that the origin of the intrinsic symmetry breaking is nonlinearity, which produces instability at the instance when the evolution crosses an inflexion point, where this instability breaks the original symmetry.

  17. Development of Safety Analysis Codes and Experimental Validation for a Very High Temperature Gas-Cooled Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Chang, H. Oh, PhD; Cliff Davis; Richard Moore

    2004-11-01

    The very high temperature gas-cooled reactors (VHTGRs) are those concepts that have average coolant temperatures above 900 degrees C or operational fuel temperatures above 1250 degrees C. These concepts provide the potential for increased energy conversion efficiency and for high-temperature process heat application in addition to power generation and nuclear hydrogen generation. While all the High Temperature Gas Cooled Reactor (HTGR) concepts have sufficiently high temperatures to support process heat applications, such as desalination and cogeneration, the VHTGR's higher temperatures are suitable for particular applications such as thermochemical hydrogen production. However, the high temperature operation can be detrimental to safety following a loss-of-coolant accident (LOCA) initiated by pipe breaks caused by seismic or other events. Following the loss of coolant through the break and coolant depressurization, air from the containment will enter the core by molecular diffusion and ultimately by natural convection, leading to oxidation of the in-core graphite structures and fuel. The oxidation will release heat and accelerate the heatup of the reactor core. Thus, without any effective countermeasures, a pipe break may lead to significant fuel damage and fission product release. The Idaho National Engineering and Environmental Laboratory (INEEL) has investigated this event for the past three years for the HTGR. However, the computer codes used, and in fact none of the world's computer codes, have been sufficiently developed and validated to reliably predict this event. New code development, improvement of the existing codes, and experimental validation are imperative to narrow the uncertaninty in the predictions of this type of accident. The objectives of this Korean/United States collaboration are to develop advanced computational methods for VHTGR safety analysis codes and to validate these computer codes.

  18. Symmetries, Symmetry Breaking, Gauge Symmetries

    CERN Document Server

    Strocchi, Franco

    2015-01-01

    The concepts of symmetry, symmetry breaking and gauge symmetries are discussed, their operational meaning being displayed by the observables {\\em and} the (physical) states. For infinitely extended systems the states fall into physically disjoint {\\em phases} characterized by their behavior at infinity or boundary conditions, encoded in the ground state, which provide the cause of symmetry breaking without contradicting Curie Principle. Global gauge symmetries, not seen by the observables, are nevertheless displayed by detectable properties of the states (superselected quantum numbers and parastatistics). Local gauge symmetries are not seen also by the physical states; they appear only in non-positive representations of field algebras. Their role at the Lagrangian level is merely to ensure the validity on the physical states of local Gauss laws, obeyed by the currents which generate the corresponding global gauge symmetries; they are responsible for most distinctive physical properties of gauge quantum field ...

  19. On Anomaly Mediated SUSY Breaking

    CERN Document Server

    de Alwis, S P

    2008-01-01

    A discrepancy between the Anomaly Mediated Supersymmetry Breaking (AMSB) gaugino mass calculated from the work of Kaplunovsky and Louis (hep-th/9402005) (KL) and other calculations in the literature is explained, and it is argued that the KL expression is the correct one relevant to the Wilsonian action. Furthermore it is argued that the AMSB contribution to the squark and slepton masses should be replaced by the contribution pointed out by Dine and Seiberg (DS) which has nothing to do with Weyl anomalies. This is not in general equivalent to the AMSB expression, and it is shown that there are models in which the usual AMSB expression would vanish but the DS one is non-zero. In fact the latter has aspects of both AMSB and gauge mediated SUSY breaking. In particular like the latter, it gives positive squared masses for sleptons.

  20. Renormalizable theories with symmetry breaking

    CERN Document Server

    Becchi, Carlo M

    2016-01-01

    The description of symmetry breaking proposed by K. Symanzik within the framework of renormalizable theories is generalized from the geometrical point of view. For an arbitrary compact Lie group, a soft breaking of arbitrary covariance, and an arbitrary field multiplet, the expected integrated Ward identities are shown to hold to all orders of renormalized perturbation theory provided the Lagrangian is suitably chosen. The corresponding local Ward identity which provides the Lagrangian version of current algebra through the coupling to an external, classical, Yang-Mills field, is then proved to hold up to the classical Adler-Bardeen anomaly whose general form is written down. The BPHZ renormalization scheme is used throughout in such a way that the algebraic structure analyzed in the present context may serve as an introduction to the study of fully quantized gauge theories.

  1. Breaking through the tranfer tunnel

    CERN Multimedia

    Laurent Guiraud

    2001-01-01

    This image shows the tunnel boring machine breaking through the transfer tunnel into the LHC tunnel. Proton beams will be transferred from the SPS pre-accelerator to the LHC at 450 GeV through two specially constructed transfer tunnels. From left to right: LHC Project Director, Lyn Evans; CERN Director-General (at the time), Luciano Maiani, and Director for Accelerators, Kurt Hubner.

  2. Explaining quantum spontaneous symmetry breaking

    Science.gov (United States)

    Liu, Chuang; Emch, Gérard G.

    Two accounts of quantum symmetry breaking (SSB) in the algebraic approach are compared: the representational and the decompositional account. The latter account is argued to be superior for understanding quantum SSB. Two exactly solvable models are given as applications of our account: the Weiss-Heisenberg model for ferromagnetism and the BCS model for superconductivity. Finally, the decompositional account is shown to be more conducive to the causal explanation of quantum SSB.

  3. Literary Careers: Breaks and Stalls

    OpenAIRE

    Crozier, W. Ray

    2001-01-01

    In his article, "Literary Careers: Breaks and Stalls," W. Ray Crozier argues that biographical evidence points to considerable individual variation in writers' output over the life span even when allowance is made for longevity and length of writing career. This issue has been neglected by psychological accounts of creativity. Crozier outlines a theoretical framework for understanding variation in terms of an "artistic career." This is conceptualised as a sequence of projects, the success of ...

  4. Applying process mapping and analysis as a quality improvement strategy to increase the adoption of fruit, vegetable, and water breaks in Australian primary schools.

    Science.gov (United States)

    Biggs, Janice S; Farrell, Louise; Lawrence, Glenda; Johnson, Julie K

    2014-03-01

    Over the past decade, public health policy in Australia has prioritized the prevention and control of obesity and invested in programs that promote healthy eating-related behaviors, which includes increasing fruit and vegetable consumption in children. This article reports on a study that used process mapping and analysis as a quality improvement strategy to improve the delivery of a nutrition primary prevention program delivered in primary schools in New South Wales, Australia. Crunch&Sip® has been delivered since 2008. To date, adoption is low with only 25% of schools implementing the program. We investigated the cause of low adoption and propose actions to increase school participation. We conducted semistructured interviews with key stakeholders and analyzed the process of delivering Crunch&Sip to schools. Interviews and process mapping and analysis identified a number of barriers to schools adopting the program. The analyses identified the need to simplify and streamline the process of delivering the program to schools and introduce monitoring and feedback loops to track ongoing participation. The combination of stakeholder interviews and process mapping and analysis provided important practical solutions to improving program delivery and also contributed to building an understanding of factors that help and hinder program adoption. The insight provided by this analysis helped identify usable routine measures of adoption, which were an improvement over those used in the existing program plan. This study contributed toward improving the quality and efficiency of delivering a health promoting program to work toward achieving healthy eating behaviors in children.

  5. Correlation analysis of symmetry breaking in the surface nanostructure ordering: case study of the ventral scale of the snake Morelia viridis

    Science.gov (United States)

    Kovalev, A.; Filippov, A.; Gorb, S. N.

    2016-03-01

    In contrast to the majority of inorganic or artificial materials, there is no ideal long-range ordering of structures on the surface in biological systems. Local symmetry of the ordering on biological surfaces is also often broken. In the present paper, the particular symmetry violation was analyzed for dimple-like nano-pattern on the belly scales of the skin of the pythonid snake Morelia viridis using correlation analysis and statistics of the distances between individual nanostructures. The results of the analysis performed on M. viridis were compared with a well-studied nano-nipple pattern on the eye of the sphingid moth Manduca sexta, used as a reference. The analysis revealed non-random, but very specific symmetry violation. In the case of the moth eye, the nano-nipple arrangement forms a set of domains, while in the case of the snake skin, the nano-dimples arrangement resembles an ordering of particles (molecules) in amorphous (glass) state. The function of the nano-dimples arrangement may be to provide both friction and strength isotropy of the skin. A simple model is suggested, which provides the results almost perfectly coinciding with the experimental ones. Possible mechanisms of the appearance of the above nano-formations are discussed.

  6. On the Translating Styles of Two Chinese Versions in Break, Break, Break%评Break,Break,Break两种译文的翻译风格

    Institute of Scientific and Technical Information of China (English)

    许颖红

    2011-01-01

    美国著名翻译家提莫志克指出,翻译就其本质而言只能是一部分翻译,忠实地再现原文所有的信息根本不可能,诗歌的准确翻译就更不容易了。对丁尼生的一首短诗的两种译文进行评析,希望通过分析能对此诗有更深刻的理解。%Tymocko, famous American translator, points out that translation is actually only the translation of part of the language because it is impossible to reproduce all the messages. It is even more difiqeuh to translate a poem. For profound understanding, this paper contrasts two Chinese versions of Break, Break, Break, a short poem of Tennyson.

  7. Cloning and expression of the cDNA encoding the FXPRL family of peptides and a functional analysis of their effect on breaking pupal diapause in Helicoverpa armigera.

    Science.gov (United States)

    Zhang, Tian-Yi; Sun, Jiu-Song; Zhang, Liu-Bin; Shen, Jin-Liang; Xu, Wei-Hua

    2004-01-01

    Diapause hormone (DH) and pheromone biosynthesis activating neuropeptide (PBAN) are encoded by a single mRNA in the suboesophegeal ganglion (SG) and are responsible for induction of embryonic diapause in Bombyx mori and sex pheromone biosynthesis in lepidopteran insects. PBAN cDNA analyses revealed that the DH-like peptide is present in several species that have a pupal diapause. However, the function of the DH-like peptide remains unknown. In the present study, we cloned the cDNA encoding DH-PBAN in Helicoverpa armigera utilizing the rapid amplification of the cDNA ends method. The nucleotide se quence analysis revealed that the longest open reading frame of this cDNA encodes a 194-amino acid precursor protein that con tains a 33-aa PBAN, a 24-aa DH-like peptide, and three other neuropeptides, all of which have a common C-terminal pentapeptide motif FXPR/KL ( X=G, T, S). A homology search showed that H. armigera DH-like and PBAN are highly homologous to those from other insects. Northern blot analysis demonstrated a single message RNA corresponding to the size of Har-DH-PBAN cDNA from pupal SG with significantly higher expression in the SG of nondiapause pupae than diapausing pupae. Western blot analysis showed DH-like peptide expression from SG of both males and females. When DH-like peptide was injected into nondiapause larvae and pupae, it did not induce diapause, but rather efficiently broke pupal diapause in H. armigera. The ED(50) of DH to terminate pupal diapause is 20 pmol/pupae. The other four FXPRLamide neuropeptides from the DH-PBAN polyprotein precursor have cross activity for diapause termination. These observations therefore suggest a potential role for these FXPRL family peptides in promoting continuous development in several noctuid species. The high expression of this gene in pharate adults and adults indicates that the FXPRL family peptides may have multiple physiological functions.

  8. Safety analysis of a loss-of-coolant accident in a breeding blanket for experimental fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Rocco, P.; Casini, G.; Djerassi, H.; Papa, L.; Pautasso, G.; Renda, V.; Rouyer, J.L.

    1985-07-01

    A LOCA in a blanket design proposed for NET (Next European Torus) is investigated. The structural analysis of a damaged breeder unit shows that this first containment barrier has a high probability of survival to this accident. The radioactive sources involved are evaluated and an assessment is made of all containment barriers and associated protection systems.

  9. Robot-assisted laparoscopic prostatectomy: a costs and break-even point analysis for decision-making in a university hospital and a regional healthcare system in Northern Italy

    Directory of Open Access Journals (Sweden)

    Elisa Fabbro

    2014-12-01

    Full Text Available BACKGROUND: Robotic Assisted Radical Prostatectomy (RALP is one of the most expensive urological innovations. Prices of the “Da Vinci System” range from € 761.105 to € 1.902.762 for each unit, without taking into account the cost of maintenance and the use of additional devices. We evaluated outcomes, and costs retrospectively, comparing RALP to open retro-pubic radical prostatectomy (RRP performed in our hospital between December 2009 and December 2010.METHODS: We compared 53 RALP, and 50 RRP in terms of costs, and clinical outcomes. We also implemented a Break Even Analysis in order to evaluate if the public reimbursement covered the total cost of RALP.RESULTS: According to our analysis, RALP showed lower hospitalization (p < 0,0001, higher early continence rate  (p < 0,0001, better potency rate in nerve sparing procedures  (p < 0,0142, and required no transfusions. Excluding the cost of purchasing and maintenance, single case costs were € 6.046,08 for RALP and € 4.834,11 for RRP, respectively. Considering the affordability of the technology, the point where the total revenue is sufficient to cover the total costs is an average of 60 cases performed per year, only in presence of additional reimbursement.CONCLUSIONS: Although our clinical analysis shows better results in favour of RALP, the economical analysis shows that RALP's costs are consistently higher than RRP. Considering also the purchasing costs, we demonstrate that the health gain of the technology does not necessarily offset the higher costs, even in a large, university hospital (1.000 beds. 

  10. Analysis study of the condensation heat transfer coefficient in the presence of noncondensable on PCCS vertical condenser tube using MARS-KS

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Dong jae; Jang, Yeong jun; Lee, Yeon-Gun [Jeju National University, Jeju (Korea, Republic of); Kim, Sin [Chung-Ang University, Seoul (Korea, Republic of)

    2015-10-15

    The Passive Containment Cooling System (PCCS) to be introduced in advanced LWRs removes released energy to an external heat sink by a naturally driven flow. Containment through the condensation heat transfer phenomenon in the event of the loss of coolant accident (LOCA) or main steam line break (MSLB). As the released steam pressurizes the containment, the PCCS will activate to transport the decay heat In this study, a numerical analysis of the condensation heat transfer coefficients on the PCCS condenser tube is conducted using the MARS-KS code. The condensation heat transfer coefficients are obtained from JNU condensation tests performed on a 1000 long and 40 mm O.D. tube. The analysis condition covers 2 and 4 bar for the air mass fraction ranging from 0.1 to 0.8. The JNU single vertical condensation experimental results, Uchida's and Dehbi's correlation compared with the MARS-KS code's results at 2 and 4 bar. Experimental results and MARS-KS predicted heat transfer coefficient is different from the thermal resistances and Wall subcooling. An average relative error is 18.8% and 15% at 2 and 4 bar, respectively. Uchida's correlation is considered the noncondensable gas mass fraction only. Therefore, that is lower than MARS-KS results at 4 bar. Dehbi's correlation affected by ratio of the height-to-diameter, so its results are higher condensation heat transfer coefficient than MARS-KS predicted results.

  11. Leaders break ground for INFINITY

    Science.gov (United States)

    2008-01-01

    Community leaders from Mississippi and Louisiana break ground for the new INFINITY at NASA Stennis Space Center facility during a Nov. 20 ceremony. Groundbreaking participants included (l to r): Gottfried Construction representative John Smith, Mississippi Highway Commissioner Wayne Brown, INFINITY board member and Apollo 13 astronaut Fred Haise, Stennis Director Gene Goldman, Studio South representative David Hardy, Leo Seal Jr. family representative Virginia Wagner, Hancock Bank President George Schloegel, Mississippi Rep. J.P. Compretta, Mississippi Band of Choctaw Indians representative Charlie Benn and Louisiana Sen. A.G. Crowe.

  12. History of electroweak symmetry breaking

    CERN Document Server

    Kibble, T W B

    2015-01-01

    In this talk, I recall the history of the development of the unified electroweak theory, incorporating the symmetry-breaking Higgs mechanism, as I saw it from my standpoint as a member of Abdus Salam's group at Imperial College. I start by describing the state of physics in the years after the Second World War, explain how the goal of a unified gauge theory of weak and electromagnetic interactions emerged, the obstacles encountered, in particular the Goldstone theorem, and how they were overcome, followed by a brief account of more recent history, culminating in the historic discovery of the Higgs boson in 2012.

  13. Unsuitability of lymphoblastoid cell lines as surrogate of cryopreserved isolated lymphocytes for the analysis of DNA double-strand break repair activity

    Energy Technology Data Exchange (ETDEWEB)

    Zijno, Andrea [Department of Environment and Primary Prevention, Istituto Superiore di Sanita, Rome (Italy); Porcedda, Paola [Department of Clinical and Biological Sciences, University of Turin (Italy); Saini, Francesca [Department of Environment and Primary Prevention, Istituto Superiore di Sanita, Rome (Italy); Allione, Alessandra [Institute for Scientific Interchange (ISI) Foundation, Villa Gualino, Turin (Italy); Garofalo, Bruno; Marcon, Francesca [Department of Environment and Primary Prevention, Istituto Superiore di Sanita, Rome (Italy); Guarrera, Simonetta [Institute for Scientific Interchange (ISI) Foundation, Villa Gualino, Turin (Italy); Turinetto, Valentina; Minieri, Valentina [Department of Clinical and Biological Sciences, University of Turin (Italy); Funaro, Ada [Department of Genetics, Biology and Biochemistry, University of Turin (Italy); Crebelli, Riccardo [Department of Environment and Primary Prevention, Istituto Superiore di Sanita, Rome (Italy); Giachino, Claudia [Department of Clinical and Biological Sciences, University of Turin (Italy); Matullo, Giuseppe, E-mail: giuseppe.matullo@unito.it [Institute for Scientific Interchange (ISI) Foundation, Villa Gualino, Turin (Italy); Department of Genetics, Biology and Biochemistry, University of Turin (Italy)

    2010-02-03

    As first task of a comprehensive investigation on DNA repair genotype-phenotype correlations, the suitability of Epstein-Barr virus (EBV)-transformed lymphoblastoid cell lines (LCLs) as surrogate of cryopreserved peripheral blood mononuclear cells (PBMCs) in DNA repair phenotypic assays was evaluated. To this aim the amount of DNA damage induced by {gamma}-rays and DNA repair capacity were evaluated in unstimulated (G{sub 0}) and mitogen-simulated (G{sub 2}) PBMC from 20 healthy subjects and in EBV-transformed LCL obtained from the same individuals. Phosphorylation of histone H2AX, micronuclei and chromosomal aberrations were the end-points investigated. The results obtained show higher basal frequencies of binucleated cells bearing micronuclei and nucleoplasmic bridge (NPB) in LCL with respect to PBMC, suggesting that EBV transformation may be associated with chromosomal instability. After irradiation, higher levels of micronuclei were induced in G{sub 0}-treated PBMC compared to cycling LCL; conversely, NPB were more frequent in LCL than in PBMC. Moreover, higher levels of chromosomal aberrations were observed in G{sub 2}-treated PBMC compared to LCL. Concerning {gamma}-H2AX measurements, phosphorylation levels 1 h after treatment and dephosphorylation kinetics were basically similar in LCL and in PBMC. However, while Spearman's test showed a strong correlation between the results obtained in replicated experiments with PBMC, high inter-experimental variability and poor reproducibility was observed in the experiments performed with LCL, possibly due to the intrinsic instability of LCL. In summary, both the analysis of {gamma}-H2AX and the evaluation of chromosome damage highlighted a larger inter-experimental variability in the results obtained with LCL compared to PBMC. Noteworthy, the two set of results proved to lack any significant correlation at the individual level. These results indicate that LCL may be unsuitable for investigating genotype

  14. Bone-breaking bite force of Basilosaurus isis (Mammalia, Cetacea from the late Eocene of Egypt estimated by finite element analysis.

    Directory of Open Access Journals (Sweden)

    Eric Snively

    Full Text Available Bite marks suggest that the late Eocence archaeocete whale Basilosaurus isis (Birket Qarun Formation, Egypt fed upon juveniles of the contemporary basilosaurid Dorudon atrox. Finite element analysis (FEA of a nearly complete adult cranium of B. isis enables estimates of its bite force and tests the animal's capabilities for crushing bone. Two loadcases reflect different biting scenarios: 1 an intitial closing phase, with all adductors active and a full condylar reaction force; and 2 a shearing phase, with the posterior temporalis active and minimized condylar force. The latter is considered probable when the jaws were nearly closed because the preserved jaws do not articulate as the molariform teeth come into occulusion. Reaction forces with all muscles active indicate that B. isis maintained relatively greater bite force anteriorly than seen in large crocodilians, and exerted a maximum bite force of at least 16,400 N at its upper P3. Under the shearing scenario with minimized condylar forces, tooth reaction forces could exceed 20,000 N despite lower magnitudes of muscle force. These bite forces at the teeth are consistent with bone indentations on Dorudon crania, reatract-and-shear hypotheses of Basilosaurus bite function, and seizure of prey by anterior teeth as proposed for other archaeocetes. The whale's bite forces match those estimated for pliosaurus when skull lengths are equalized, suggesting similar tradeoffs of bite function and hydrodynamics. Reaction forces in B. isis were lower than maxima estimated for large crocodylians and carnivorous dinosaurs. However, comparison of force estimates from FEA and regression data indicate that B. isis exerted the largest bite forces yet estimated for any mammal, and greater force than expected from its skull width. Cephalic feeding biomechanics of Basilosaurus isis are thus consistent with habitual predation.

  15. A Study of the Rock Breaking Mechanism during Swirling Water Jet Drilling

    Institute of Scientific and Technical Information of China (English)

    NiHongjian; WangRuihe

    2004-01-01

    Based on an analysis of the factors affecting rock breaking and the coupling between rock and fluid during water jet drilling, the rock damage model and the damage-coupling model suitable for the whole rock breaking process under the water jet is established with continuous damage mechanics and micro-damage mechanics. The evolvement of rock damage during swirling water jet drilling is simulated on a nonlinear FEM and dynamic rock damage model, and a decoupled method is used to analyze the rock damage. The numerical results agree with the test results to a high degree, which shows the rock breaking ability of the swirling water jet is strong. This is because the jet particle velocity of the swirling water jet is three-dimensional, and its rock-breaking manner mainly has a slopping impact. Thus, the interference from returning fluid is less. All these aspects make it easy to draw and shear the rock surface. The rock breaking process is to break out an annular on the rock surface first, and then the annular develops quickly in both the radial and axial directions, the last part of the rock broken hole bottom is a protruding awl. The advantage of the swirling water jet breaking rock is the heavy breaking efficiency, large breaking area and less energy used to break rock per unite volume, so the swirling water jet can drill in a hole of a large diameter.

  16. DNA Double-Strand Break Analysis by {gamma}-H2AX Foci: A Useful Method for Determining the Overreactors to Radiation-Induced Acute Reactions Among Head-and-Neck Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Goutham, Hassan Venkatesh; Mumbrekar, Kamalesh Dattaram [Division of Radiobiology and Toxicology, Manipal Life Sciences Centre, Manipal University, Manipal, Karnataka (India); Vadhiraja, Bejadi Manjunath [Manipal Hospital, Bangalore, Karnataka (India); Fernandes, Donald Jerard; Sharan, Krishna [Department of Radiotherapy and Oncology, Shiridi Sai Baba Cancer Hospital and Research Centre, Kasturba Hospital, Manipal, Karnataka (India); Kanive Parashiva, Guruprasad; Kapaettu, Satyamoorthy [Division of Biotechnology, Manipal Life Sciences Centre, Manipal University, Manipal, Karnataka (India); Bola Sadashiva, Satish Rao, E-mail: satishraomlsc@gmail.com [Division of Radiobiology and Toxicology, Manipal Life Sciences Centre, Manipal University, Manipal, Karnataka (India)

    2012-12-01

    Purpose: Interindividual variability in normal tissue toxicity during radiation therapy is a limiting factor for successful treatment. Predicting the risk of developing acute reactions before initiation of radiation therapy may have the benefit of opting for altered radiation therapy regimens to achieve minimal adverse effects with improved tumor cure. Methods and Materials: DNA double-strand break (DSB) induction and its repair kinetics in lymphocytes of head-and-neck cancer patients undergoing chemoradiation therapy was analyzed by counting {gamma}-H2AX foci, neutral comet assay, and a modified version of neutral filter elution assay. Acute normal tissue reactions were assessed by Radiation Therapy Oncology Group criteria. Results: The correlation between residual DSBs and the severity of acute reactions demonstrated that residual {gamma}-H2AX foci in head-and-neck cancer patients increased with the severity of oral mucositis and skin reaction. Conclusions: Our results suggest that {gamma}-H2AX analysis may have predictive implications for identifying the overreactors to mucositis and skin reactions among head-and-neck cancer patients prior to initiation of radiation therapy.

  17. BF型防坠器缓冲绳在制动过程中的作用分析%Function Analysis on Buffer Rope of BF-type Safety Catch in Breaking Process

    Institute of Scientific and Technical Information of China (English)

    李令德; 贺彩龙

    2015-01-01

    针对BF型防坠器在实际使用中需要进行合理调试等问题,重点介绍了防坠器在制动过程中各主要部件运动参数的关系,通过对制动过程的速度、时间、距离等参数的分析,分析了缓冲绳在制动过程中所起的作用,得出在缓冲器中缓冲绳被抽出距离应大于22.5 mm。%Aiming at some issues of BF type safety catch machine such as reasonable adjustment in application, relations a-mong the motion parameters of major parts in the safety catch during the breaking process are focused in this article.Based on analysis of some parameters such as speed, duration and length, function of the buffer rope is acknowledged, and a conclusion that the pulling length of the buffer rope in safety catch should be 22.5 mm is drawn.

  18. 某超高射速舰炮弹药筒膛内横断问题技术分析%Technical Analysis of Cartridge Breaking in Bore for Super-high Firing Rate Naval Gun

    Institute of Scientific and Technical Information of China (English)

    马献怀

    2015-01-01

    针对某超高射速舰炮及其弹道炮试验过程中出现的药筒膛内横断问题,通过现场勘测、理论分析和故障还原试验,确定了故障原因。根据故障机理,经技术攻关,提出了解决措施,经过后续多次射击试验验证,故障再未复现,证明了解决措施的可行有效。分析结果对解决速射火炮类似故障有重要的参考价值。%Aimed at the cartridge breaking problem occurred during the test of super-high firing rate naval gun and ballistic gun,the failure causes were determined by site investigation,theo-retical analysis and failure reproduction test.The solution was proposed based on the failure mechanism and technology research.The same failure hasn't occurred again during many firing test.The results show the solution is reasonable and feasible,which provides an important ref-erence value for solving similar failure of rapid-fire gun.

  19. Introduction to Electroweak Symmetry Breaking

    Energy Technology Data Exchange (ETDEWEB)

    Dawson,S.

    2008-10-02

    The Standard Model (SM) is the backbone of elementary particle physics-not only does it provide a consistent framework for studying the interactions of quark and leptons, but it also gives predictions which have been extensively tested experimentally. In these notes, I review the electroweak sector of the Standard Model, discuss the calculation of electroweak radiative corrections to observables, and summarize the status of SM Higgs boson searches. Despite the impressive experimental successes, however, the electroweak theory is not completely satisfactory and the mechanism of electroweak symmetry breaking is untested. I will discuss the logic behind the oft-repeated statement: 'There must be new physics at the TeV scale'. These lectures reflect my strongly held belief that upcoming results from the LHC will fundamentally change our understanding of electroweak symmetry breaking. In these lectures, I review the status of the electroweak sector of the Standard Model, with an emphasis on the importance of radiative corrections and searches for the Standard Model Higgs boson. A discussion of the special role of the TeV energy scale in electroweak physics is included.

  20. Chiral symmetry breaking and monopoles

    CERN Document Server

    Di Giacomo, Adriano; Pucci, Fabrizio

    2015-01-01

    To understand the relation between the chiral symmetry breaking and monopoles, the chiral condensate which is the order parameter of the chiral symmetry breaking is calculated in the $\\overline{\\mbox{MS}}$ scheme at 2 [GeV]. First, we add one pair of monopoles, varying the monopole charges $m_{c}$ from zero to four, to SU(3) quenched configurations by a monopole creation operator. The low-lying eigenvalues of the Overlap Dirac operator are computed from the gauge links of the normal configurations and the configurations with additional monopoles. Next, we compare the distributions of the nearest-neighbor spacing of the low-lying eigenvalues with the prediction of the random matrix theory. The low-lying eigenvalues not depending on the scale parameter $\\Sigma$ are compared to the prediction of the random matrix theory. The results show the consistency with the random matrix theory. Thus, the additional monopoles do not affect the low-lying eigenvalues. Moreover, we discover that the additional monopoles increa...

  1. How often precipitation records break?

    Science.gov (United States)

    Papalexiou, Simon Michael; Oikonomou, Maria; Floutsakou, Athina; Bessas, Nikolaos; Mamassis, Nikos

    2016-04-01

    How often precipitation records break? Are there any factors that determine the average time needed for the next maximum to occur? In order to investigate these simple questions we use several hundreds of daily precipitation records (more than 100 years long each) and we study the time intervals between each successive maximum precipitation value. We investigate if the record breaking time interval is related (a) to the autocorrelation structure, (b) to probability dry, and (c) to the tail of the marginal distribution. For the last, we first, evaluate which type of tail is better fitted by choosing among three general types of tails corresponding to the distributions Pareto, Lognormal and Weibull; and second, we assess the heaviness of the tail based on the estimated shape parameter. The performance of each tail is evaluated in terms of return period values, i.e., we compare the empirical return periods of precipitation values above a threshold with the predicted ones by each of the three types of fitted tails.

  2. Boundary breaking for interdisciplinary learning

    Directory of Open Access Journals (Sweden)

    Adi Kidron

    2015-10-01

    Full Text Available The purpose of this work is to contribute to the body of knowledge on processesby which students develop interdisciplinary understanding of contents, as well as to suggest technology-enhanced means for supporting them in these processes in the context of higher education. In doing so, we suggest a rethinking of three traditional practices that tend to characterise typical higher education instruction: (1 compartmentalisation of disciplines; (2 traditional pedagogy; and (3 traditional hierarchies based on levels of expertise. Our high-level conjecture was that meaningful dialogue with peers and experts supports both the deepening of ideas in one knowledge domain and the formation of connections between ideas from several domains, both of which are required for the development of interdisciplinary understanding. We developed the Boundary Breaking for Interdisciplinary Learning (BBIL model, which harnesses technology to break boundaries between disciplines, learners and organisational levels of hierarchy. Findings indicate that 36 undergraduate students who participated in an interdisciplinary online course that implemented the BBIL model have significantly improved their interdisciplinary understanding of the course contents. This study illustrates how innovative use of available, free and low-cost technology can produce a ‘positive disruption’ in higher education instruction.

  3. Improved single sector supersymmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Luty, Markus A.; Terning, John

    1998-12-09

    Building on recent work by N. Arkani-Hamed and the present authors, we construct realistic models that break supersymmetry dynamically and give rise to composite quarks and leptons, all in a single strongly-coupled sector. The most important improvement compared to earlier models is that the second-generation composite states correspond to dimension-2 ''meson'' operators in the ultraviolet. This leads to a higher scale for flavor physics, and gives a completely natural suppression of flavor-changing neutral currents. We also construct models in which the hierarchy of Yukawa couplings is explained by the dimensionality of composite states. These models provide an interesting and viable alternative to gravity- and gauge-mediated models. The generic signatures are unification of scalar masses with different quantum numbers at the compositeness scale, and lighter gaugino, Higgsino, and third-generation squark and slepton masses. We also analyze large classes of models that give rise to both compositeness and supersymmetry breaking, based on gauge theories with confining, fixed-point, or free-magnetic dynamics.

  4. Chiral symmetry breaking with the Curtis-Pennington vertex

    NARCIS (Netherlands)

    Atkinson, D.; Gusynin, V. P.; Maris, P.

    1992-01-01

    Published in: Phys. Lett. B 303 (1993) 157-162 citations recorded in [Science Citation Index] Abstract: We study chiral symmetry breaking in quenched QED$_4$, using a vertex Ansatz recently proposed by Curtis and Pennington. Bifurcation analysis is employed to establish the existence of a critical c

  5. Spontaneous symmetry breaking in spinor Bose-Einstein condensates

    DEFF Research Database (Denmark)

    Scherer, Manuel; Lücke, Bernd; Peise, Jan;

    2013-01-01

    We present an analytical model for the theoretical analysis of spin dynamics and spontaneous symmetry breaking in a spinor Bose-Einstein condensate (BEC). This allows for an excellent intuitive understanding of the processes and provides good quantitative agreement with the experimental results...

  6. What can break the Wandzura--Wilczek relation?

    Energy Technology Data Exchange (ETDEWEB)

    Alessandro Bacchetta, Alberto Accardi, Wolodymyr Melnitchouk, Marc Schlegel

    2009-11-01

    We analyze the breaking of the Wandzura--Wilczek relation for the g_2 structure function, emphasizing its connection with transverse momentum dependent parton distribution functions. We find that the relation is broken by two distinct twist-3 terms, and clarify how these can be separated in measurements of double-spin asymmetries in semi-inclusive deep inelastic scattering. Through a quantitative analysis of available g_2 data we also show that the breaking of the Wandzura--Wilczek relation can be as large as 15--30% of the size of g_2.

  7. Detecting structural breaks in time series via genetic algorithms

    DEFF Research Database (Denmark)

    Doerr, Benjamin; Fischer, Paul; Hilbert, Astrid

    2016-01-01

    Detecting structural breaks is an essential task for the statistical analysis of time series, for example, for fitting parametric models to it. In short, structural breaks are points in time at which the behaviour of the time series substantially changes. Typically, no solid background knowledge...... and mutation operations for this problem, we conduct extensive experiments to determine good choices for the parameters and operators of the genetic algorithm. One surprising observation is that use of uniform and one-point crossover together gave significantly better results than using either crossover...

  8. Design and safety analysis of the helium cooled solid breeder blanket for CFETR

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shuai; Zhou, Guangming; Lv, Zhongliang; Jin, Cheng; Chen, Hongli [University of Science and Technology of China, Anhui (China). School of Nuclear Science and Technology

    2016-05-15

    This paper reports the design and safety analysis results of the helium cooled solid breeder blanket of the Chinese Fusion Engineering Test Reactor (CFETR). Materials selection and basic structure of the blanket have been presented. Performance analysis including neutronics analysis and thermo-mechanical analysis has shown good results. And the safety analysis of the blanket under Loss Of Coolant Accident (LOCA) conditions has been described. Results showed the current design can deal well with the selected accident scenarios.

  9. Experimental Study of Wave Breaking on Gentle Slope

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    -An experimental study of regular wave and irregular wave breaking is performed on a gentle slope of 1:200. In the experiment, asymmetry of wave profile is analyzed to determine its effect on wave breaker indices and to explain the difference between Goda and Nelson about the breaker indices of regular waves on very mild slopes. The study shows that the breaker index of irregular waves is under less influence of bottom slope i, relative water depth d/ L0 and the asymmetry of wave profile than that of regular waves. The breaker index of regular waves from Goda may be used in the case of irregular waves, while the coefficient A should be 0.15. The ratio of irregular wavelength to the length calculated by linear wave theory is 0.74. Analysis is also made on the waveheight damping coefficient of regular waves after breaking and on the breaking probability of large irregular waves.

  10. NUMERICAL SIMULATION OF ROCK BREAKING MECHANISM WITH HIGH-PRESSURE WATER JET

    Institute of Scientific and Technical Information of China (English)

    NI Hong-jian

    2004-01-01

    Based on the analysis of experimental results, the rock damage model and the damage coupling model suitable for the whole rock breaking process with water jet were established with continuous damage mechanics and micro damage mechanics, and the numerical method was developed with continuum mechanics and the FEM theory. The rock breaking mechanism with water jet was studied systematically with numerical simulation for the first time in the field of water-jet rock breaking. The numerical results agree with the experimental ones which shows that the presented method is reasonable and can reflect the reality of water-jet rock breaking. The conclusion can be applied in practice.

  11. A report on the leak before break design and evaluation of LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Bum; Lee, H. Y.; Joo, Y. S.; Lee, J. H. [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2002-05-01

    In this study, the necessity of leak before break application for Liquid Metal Reactors (LMR) was investigated and the outline of leak before break evaluation procedure for KALIMER reactor structures and components was proposed. In the 1st phase of this project, the theoretical background for leak before break procedure was prepared based upon the state-of-the-art technology of the advanced countries. In the 2nd phase of project, evaluation method of creep crack growth was studied and the leak before break evaluation procedure of French RCC-MRA -16 was analyzed. Also, creep-fatigue crack growth was assessed according to the Japanese JNC method and this will help to establish the KALIMER leak before break procedure. It is necessary to specify proposed KALIMER leak before break evaluation technique including high temperature crack growth evaluation, stability analysis of crack growth, leak rate evaluation method, and leak detection technology. 24 refs., 12 figs., 4 tabs. (Author)

  12. The Analysis of the Patterns of Radiation-Induced DNA Damage Foci by a Stochastic Monte Carlo Model of DNA Double Strand Breaks Induction by Heavy Ions and Image Segmentation Software

    Science.gov (United States)

    Ponomarev, Artem; Cucinotta, F.

    2011-01-01

    To create a generalized mechanistic model of DNA damage in human cells that will generate analytical and image data corresponding to experimentally observed DNA damage foci and will help to improve the experimental foci yields by simulating spatial foci patterns and resolving problems with quantitative image analysis. Material and Methods: The analysis of patterns of RIFs (radiation-induced foci) produced by low- and high-LET (linear energy transfer) radiation was conducted by using a Monte Carlo model that combines the heavy ion track structure with characteristics of the human genome on the level of chromosomes. The foci patterns were also simulated in the maximum projection plane for flat nuclei. Some data analysis was done with the help of image segmentation software that identifies individual classes of RIFs and colocolized RIFs, which is of importance to some experimental assays that assign DNA damage a dual phosphorescent signal. Results: The model predicts the spatial and genomic distributions of DNA DSBs (double strand breaks) and associated RIFs in a human cell nucleus for a particular dose of either low- or high-LET radiation. We used the model to do analyses for different irradiation scenarios. In the beam-parallel-to-the-disk-of-a-flattened-nucleus scenario we found that the foci appeared to be merged due to their high density, while, in the perpendicular-beam scenario, the foci appeared as one bright spot per hit. The statistics and spatial distribution of regions of densely arranged foci, termed DNA foci chains, were predicted numerically using this model. Another analysis was done to evaluate the number of ion hits per nucleus, which were visible from streaks of closely located foci. In another analysis, our image segmentaiton software determined foci yields directly from images with single-class or colocolized foci. Conclusions: We showed that DSB clustering needs to be taken into account to determine the true DNA damage foci yield, which helps to

  13. Time-symmetry breaking in turbulence

    CERN Document Server

    Jucha, Jennifer; Pumir, Alain; Bodenschatz, Eberhard

    2014-01-01

    In three-dimensional turbulent flows, the flux of energy from large to small scales breaks time symmetry. We show here that this irreversibility can be quantified by following the relative motion of several Lagrangian tracers. We find by analytical calculation, numerical analysis and experimental observation that the existence of the energy flux implies that, at short times, two particles separate temporally slower forwards than backwards, and the difference between forward and backward dispersion grows as $t^3$. We also find the geometric deformation of material volumes, surrogated by four points spanning an initially regular tetrahedron, to show sensitivity to the time-reversal with an effect growing linearly in $t$. We associate this with the structure of the strain rate in the flow.

  14. 电容器组单相断线故障继电保护拒动行为分析%Behavior analysis for relay protection during single-phase wire-breaking fault of capacitor bank

    Institute of Scientific and Technical Information of China (English)

    曾锦松

    2012-01-01

    The unbalanced voltage protection is designed based on the voltage drift of neutral point during capacitor faults to effectively isolate the asymmetric faults of capacitor, but it may refuse to act when the single-phase wire-breaking fault happens in the ungrounded star-connecting capacitor bank,which is pointed out by the theoretical analysis in principle. As there is negative-sequence current in such case,the negative-sequence current protection is proposed to prevent the improper behaviour of unbalanced voltage protection, which is verified by theoretical analysis.%不平衡电压保护是隔离电容器不对称故障的有效手段,该保护的设计建立在电容器故障时中性点电压漂移的基础上.工程实践表明,在单星形不接地电容器组发生单相断线时,该原理会导致电容器保护拒动.为解决此问题,通过理论分析,指出传统的电容器不平衡电压保护存在不能反映单星形不接地电容器组断线故障的原理性缺陷;而后基于单星形不接地电容器组发生断线故障时存在负序电流的特点,提出负序电流的保护方案.理论分析表明,该方案可以防止电容器发生断线故障时保护出现拒动现象.

  15. Abundant Multisoliton Structure of (3+1)-Dimensional Breaking Soliton Equation

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hong; BAI Cheng-Lin

    2004-01-01

    Using the extended homogeneous balance method, we obtained abundant exact solution structures of the (3+ 1 )-dimensional breaking soliton equation. By means of the leading order term analysis, the nonlinear transformations of the (3t1)-dimensional breaking soliton equation are given first, and then some special types of single solitary wave solutions and the multisoliton solutions are constructed.

  16. Sediment transport under breaking waves

    DEFF Research Database (Denmark)

    Christensen, Erik Damgaard; Hjelmager Jensen, Jacob; Mayer, Stefan

    2000-01-01

    The sediment transport in the surf zone is modelled by combining a Navier-Stokes solver, a free surface model, a turbulence model, and a sediment transport model. The flow solver is based on the finite volume technique for non-orthogonal grids. The model is capable of simulating the turbulence...... generated at the surface where the wave breaks as well as the turbulence generated near the bed due to the wave-motion and the undertow. In general, the levels of turbulent kinetic energy are found to be higher than experiments show. This results in an over prediction of the sediment transport. Nevertheless......, some qualitative features have been modelled with success such as the onshore transport under plunging breakers and offshore transport under spilling breakers....

  17. Dynamical centrosymmetry breaking in graphene

    CERN Document Server

    Carvalho, David N; Biancalana, Fabio

    2016-01-01

    We discover an unusual phenomenon that occurs when a graphene monolayer is illuminated by a short and intense pulse at normal incidence. Due to the pulse-induced oscillations of the Dirac cones, a dynamical breaking of the layer's centrosymmetry takes place, leading to the generation of second harmonic waves. We prove that this result can only be found by using the full Dirac equation and show that the widely used semiconductor Bloch equations fail to reproduce this and some other important physics of graphene. Our results open new windows in the understanding of nonlinear light-matter interactions in a wide variety of new 2D materials with a gapped or ungapped Dirac-like dispersion.

  18. Electroweak symmetry breaking via QCD.

    Science.gov (United States)

    Kubo, Jisuke; Lim, Kher Sham; Lindner, Manfred

    2014-08-29

    We propose a new mechanism to generate the electroweak scale within the framework of QCD, which is extended to include conformally invariant scalar degrees of freedom belonging to a larger irreducible representation of SU(3)c. The electroweak symmetry breaking is triggered dynamically via the Higgs portal by the condensation of the colored scalar field around 1 TeV. The mass of the colored boson is restricted to be 350  GeV≲mS≲3  TeV, with the upper bound obtained from perturbative renormalization group evolution. This implies that the colored boson can be produced at the LHC. If the colored boson is electrically charged, the branching fraction of the Higgs boson decaying into two photons can slightly increase, and moreover, it can be produced at future linear colliders. Our idea of nonperturbative electroweak scale generation can serve as a new starting point for more realistic model building in solving the hierarchy problem.

  19. Simulación de operación de una central nuclear con el simulador gráfico interactivo: LOCA en rama fría en BOL, MOL y EOL

    OpenAIRE

    Penche Alonso, Marta

    2016-01-01

    La energía nuclear convencional se basa en reacciones de fisión producidas cuando los átomos de uranio absorben neutrones. Se tratan de reacciones autosostenidas en el combustible del reactor nuclear. Este trabajo se enmarca dentro del campo de la seguridad nuclear, estudiando, mediante simulaciones, el desarrollo del accidente base de diseño LOCA. En la seguridad de una central nuclear hay varios niveles: - Primer nivel: la prevención de accidentes. - Segundo nivel: el control de la...

  20. Modelling approach for gravity dam break analysis

    Directory of Open Access Journals (Sweden)

    Boussekine Mourad

    2016-09-01

    Full Text Available The construction of dams in rivers can provide considerable benefits such as the supply of drinking and irrigation water; however the consequences which would result in the event of their failure could be catastrophic. They vary dramatically depending on the extent of the inundation area, the size of the population at risk.

  1. Gravity with background fields and diffeomorphism breaking

    CERN Document Server

    Bluhm, Robert

    2016-01-01

    Effective gravitational field theories with background fields break local Lorentz symmetry and diffeomorphism invariance. Examples include Chern-Simons gravity, massive gravity, and the Standard-Model Extension (SME). The physical properties and behavior of these theories depend greatly on whether the spacetime symmetry breaking is explicit or spontaneous. With explicit breaking, the background fields are fixed and nondynamical, and the resulting theories are fundamentally different from Einstein's General Relativity (GR). However, when the symmetry breaking is spontaneous, the background fields are dynamical in origin, and many of the usual features of Einstein's GR still apply.

  2. APT Blanket System Loss-of-Coolant Accident (LOCA) Based on Initial Conceptual Design - Case 2: with Beam Shutdown Only

    Energy Technology Data Exchange (ETDEWEB)

    Hamm, L.L.

    1998-10-07

    This report is one of a series of reports that document normal operation and accident simulations for the Accelerator Production of Tritium (APT) blanket heat removal system. These simulations were performed for the Preliminary Safety Analysis Report. This report documents the results of simulations of a Loss-of-Flow Accident (LOFA) where power is lost to all of the pumps that circulate water in the blanket region, the accelerator beam is shut off and neither the residual heat removal nor cavity flood systems operate.

  3. Determination and Analysis of the Static Breaking Agent Expansion Pressure Variation%静态破碎剂膨胀压力变化规律测定与分析

    Institute of Scientific and Technical Information of China (English)

    赵杰成

    2015-01-01

    In order to fully know the expanding pressure size and variation of the static breaking agent, using resistance strain gauge measur-ing method in the laboratory, according to the test results, the static breaking agent expansion pressure are generated within 2 hours, maximum inflation pressure up to 55MPa. Static breaking agent expansion pressure generation time is short, when using the static breaking agent to break rocks, arranging the process and steps reasonably, all procedures to be finished in short time.%为全面掌握静态破碎剂产生的膨胀压力大小及变化规律, 实验室采用电阻应变片测量法测定静态破碎剂膨胀压力, 根据试验汇总结果得出静态破碎剂膨胀压力主要产生于从拌制好药剂开始反应的2h内,最大膨胀压力可达55MPa.静态破碎剂膨胀压力产生的时间较短且集中,现场利用静态破碎剂破碎岩石或松动岩层时,要合理安排现场施工工艺和步骤,拌药、装药和封孔要在较短时间内完成.

  4. On breaks of the Indian monsoon

    Indian Academy of Sciences (India)

    Sulochana Gadgil; P V Joseph

    2003-12-01

    For over a century, the term break has been used for spells in which the rainfall over the Indian monsoon zone is interrupted. The phenomenon of `break monsoon' is of great interest because long intense breaks are often associated with poor monsoon seasons. Such breaks have distinct circulation characteristics (heat trough type circulation) and have a large impact on rainfed agriculture.Although interruption of the monsoon rainfall is considered to be the most important feature of the break monsoon, traditionally breaks have been identified on the basis of the surface pressure and wind patterns over the Indian region. We have defined breaks (and active spells) on the basis of rainfall over the monsoon zone. The rainfall criteria are chosen so as to ensure a large overlap with the traditional breaks documented by Ramamurthy (1969) and De et al (1998). We have identified these rainbreaks for 1901-89. We have also identified active spells on the basis of rainfall over the Indian monsoon zone. We have shown that the all-India summer monsoon rainfall is significantly negatively correlated with the number of rainbreak days (correlation coefficient −0.56) and significantly positively correlated with the number of active days (correlation coefficient 0.47).Thus the interannual variation of the all-India summer monsoon rainfall is shown to be related to the number of days of rainbreaks and active spells identified here. There have been several studies of breaks (and also active spells in several cases) identified on the basis of different criteria over regions differing in spatial scales (e.g., Webster et al 1998; Krishnan et al 2000; Goswami and Mohan 2000; and Annamalai and Slingo 2001). We find that there is considerable overlap between the rainbreaks we have identified and breaks based on the traditional definition. There is some overlap with the breaks identified by Krishnan et al (2000) but little overlap with breaks identified by Webster et al (1998). Further

  5. Dynamical gauge symmetry breaking on the lattice

    Energy Technology Data Exchange (ETDEWEB)

    Farakos, K.; Koutsoumbas, G.; Zoupanos, G. (National Research Centre for the Physical Sciences Democritos, Athens (Greece))

    1990-10-11

    We study, using lattice techniques, the dynamical symmetry breaking of a three-dimensional theory that mimics the electroweak sector of the standard model. We show that in the strong coupling limit of a QCD-like theory the fermion condensates which are produced induce dynamical symmetry breaking of the sector corresponding to the electroweak gauge group. (orig.).

  6. Charge-symmetry-breaking nucleon form factors

    CERN Document Server

    Kubis, Bastian

    2009-01-01

    A quantitative understanding of charge-symmetry breaking is an increasingly important ingredient for the extraction of the nucleon's strange vector form factors. We review the theoretical understanding of the charge-symmetry-breaking form factors, both for single nucleons and for Helium-4.

  7. Development, validation and application of multi-point kinetics model in RELAP5 for analysis of asymmetric nuclear transients

    Energy Technology Data Exchange (ETDEWEB)

    Pradhan, Santosh K., E-mail: santosh@aerb.gov.in [Nuclear Safety Analysis Division, Atomic Energy Regulatory Board, Mumbai 400094 (India); Obaidurrahman, K. [Nuclear Safety Analysis Division, Atomic Energy Regulatory Board, Mumbai 400094 (India); Iyer, Kannan N. [Department of Mechanical Engineering, IIT Bombay, Mumbai 400076 (India); Gaikwad, Avinash J. [Nuclear Safety Analysis Division, Atomic Energy Regulatory Board, Mumbai 400094 (India)

    2016-04-15

    Highlights: • A multi-point kinetics model is developed for RELAP5 system thermal hydraulics code. • Model is validated against extensive 3D kinetics code. • RELAP5 multi-point kinetics formulation is used to investigate critical break for LOCA in PHWR. - Abstract: Point kinetics approach in system code RELAP5 limits its use for many of the reactivity induced transients, which involve asymmetric core behaviour. Development of fully coupled 3D core kinetics code with system thermal-hydraulics is the ultimate requirement in this regard; however coupling and validation of 3D kinetics module with system code is cumbersome and it also requires access to source code. An intermediate approach with multi-point kinetics is appropriate and relatively easy to implement for analysis of several asymmetric transients for large cores. Multi-point kinetics formulation is based on dividing the entire core into several regions and solving ODEs describing kinetics in each region. These regions are interconnected by spatial coupling coefficients which are estimated from diffusion theory approximation. This model offers an advantage that associated ordinary differential equations (ODEs) governing multi-point kinetics formulation can be solved using numerical methods to the desired level of accuracy and thus allows formulation based on user defined control variables, i.e., without disturbing the source code and hence also avoiding associated coupling issues. Euler's method has been used in the present formulation to solve several coupled ODEs internally at each time step. The results have been verified against inbuilt point-kinetics models of RELAP5 and validated against 3D kinetics code TRIKIN. The model was used to identify the critical break in RIH of a typical large PHWR core. The neutronic asymmetry produced in the core due to the system induced transient was effectively handled by the multi-point kinetics model overcoming the limitation of in-built point kinetics model

  8. Big break for charge symmetry

    CERN Document Server

    Miller, G A

    2003-01-01

    Two new experiments have detected charge-symmetry breaking, the mechanism responsible for protons and neutrons having different masses. Symmetry is a crucial concept in the theories that describe the subatomic world because it has an intimate connection with the laws of conservation. The theory of the strong interaction between quarks - quantum chromodynamics - is approximately invariant under what is called charge symmetry. In other words, if we swap an up quark for a down quark, then the strong interaction will look almost the same. This symmetry is related to the concept of sup i sospin sup , and is not the same as charge conjugation (in which a particle is replaced by its antiparticle). Charge symmetry is broken by the competition between two different effects. The first is the small difference in mass between up and down quarks, which is about 200 times less than the mass of the proton. The second is their different electric charges. The up quark has a charge of +2/3 in units of the proton charge, while ...

  9. Estimation of droplets/wall heat transfer under LOCA conditions in a PWR; Estimation du transfert de chaleur gouttes/paroi en situation d'APRP pour un REP

    Energy Technology Data Exchange (ETDEWEB)

    GrAdeck, M.; Maillet, D. [CNRS UMR 7563 2, 54 - Vandoeuvre les Nancy (France); Lelong, F.; Seiler, N.; Repetto, G. [IRSN Cadarache, 13 - Saint Paul lez Durance (France)

    2009-07-01

    During a LOCA (Loss Of Coolant Accident) in a PWR, the fuel assemblies could be locally severely ballooned. The transient is ended by the injection of water initiated the safety system. The cooling of theses partially blocked fuel assemblies depends on the coolant flow characteristics in the blockage region. Most models for heat transfers concentrate on cooling of the ballooned walls by vapor convection. Since a two-phase mist flow occurs when reflooding, the possibility of additional cooling by direct liquid droplet impingement on the blockage surfaces must be investigated. As the temperature of the fuel assemblies is higher than the Leidenfrost temperature, the impact regime should be only the bouncing one. Up to now, no model of heat transfer of droplet impacts has been developed for that regime. As the coolability from droplet impacts must be modeled, an experimental program was proposed with droplets and wall characteristics (velocity, diameter, temperature) close to the LOCA ones. As the interaction between the droplet and the wall is very short (a few of ms), the estimation of the heat flux during the resident time of the droplet at the wall must be accurately designed. The purpose of this work is to show how such heat flux can be experimentally estimated used an adapted inverse heat conduction model. The final goal of the present collaboration between LEMTA and IRSN is to introduce the cooling model within NEPTUNE-CFD code, a joint project of CEA, EDF, AREVA and IRSN. (authors)

  10. Research progress on dam-break floods

    KAUST Repository

    Wu, Jiansong

    2011-08-01

    Because of the catastrophic effects downstream of dam-break failure, more and more researchers around the world have been working on the study of dam-break flows to accurately forecast the downstream inundation mapping. With the rapid development of computer hardware and computing techniques, numerical study on dam-break flows has been a popular research subject. In the paper, the numerical methodologies used to solve the governing partial differential equations of dam-break flows are classified and summarized, and their characteristics and applications are discussed respectively. Furthermore, the fully-developed mathematical models developed in recent decades are reviewed, and also introduced the authors\\' on-going work. Finally, some possible future developments on modeling the dam-break flows and some solutions are presented and discussed. © 2011 IEEE.

  11. Numerical study of airflow over breaking waves

    Science.gov (United States)

    Yang, Zixuan; Shen, Lian

    2016-11-01

    We present direct numerical simulation (DNS) results on airflow over breaking waves. Air and water are simulated as a coherent system. The initial condition for the simulation is a fully-developed turbulent airflow over strongly-forced steep waves. The airflow is driven by a shear stress at the top. The effects of the initial wave steepness and wave age are studied systematically. Because wave breaking is an unsteady process, we use ensemble averaging of a large number of runs to obtain turbulent statistics. Simulation results show that the airflow above does not see the wave trough during wave breaking. Vortex structures at different stages of wave breaking are analyzed based on a linear stochastic estimation method. It is found that the wave breaking alters the pattern of vortex structures.

  12. A laboratory study of breaking waves

    Directory of Open Access Journals (Sweden)

    Jaros³aw Têgowski

    2004-09-01

    Full Text Available This paper deals with some aspects of the wave-breaking phenomenon. The objectives were to study wave-breaking criteria, and the probability of whitecap coverage under fully controlled wave conditions. An additional task was to in vestigate the characteristic spectral features of the noise produced by breaking waves and the acoustic energy generated during wave breaking events. A controlled experiment was carried out in the Ocean Basin Laboratory at MARINTEK, Trondheim (Norway. Waves were generated by a computer-controlled multi-flap wave maker, which reproduced a realistic pattern of the sea surface for the prescribed spectra. Using wave staff recordings and photographic techniques, correlations between the breaking parameters and the radiated acoustic emissions were established.

  13. Have a break: determinants of meiotic DNA double strand break (DSB) formation and processing in plants.

    Science.gov (United States)

    Edlinger, Bernd; Schlögelhofer, Peter

    2011-03-01

    Meiosis is an essential process for sexually reproducing organisms, leading to the formation of specialized generative cells. This review intends to highlight current knowledge of early events during meiosis derived from various model organisms, including plants. It will particularly focus on cis- and trans-requirements of meiotic DNA double strand break (DSB) formation, a hallmark event during meiosis and a prerequisite for recombination of genetic traits. Proteins involved in DSB formation in different organisms, emphasizing the known factors from plants, will be introduced and their functions outlined. Recent technical advances in DSB detection and meiotic recombination analysis will be reviewed, as these new tools now allow analysis of early meiotic recombination in plants with incredible accuracy. To anticipate future directions in plant meiosis research, unpublished results will be included wherever possible.

  14. Breaking soliton equations and negative-order breaking soliton equations of typical and higher orders

    Indian Academy of Sciences (India)

    ABDUL-MAJID WAZWAZ

    2016-11-01

    We develop breaking soliton equations and negative-order breaking soliton equations of typical and higher orders. The recursion operator of the KdV equation is used to derive these models.We establish the distinctdispersion relation for each equation. We use the simplified Hirota’s method to obtain multiple soliton solutions for each developed breaking soliton equation. We also develop generalized dispersion relations for the typical breaking soliton equations and the generalized negative-order breaking soliton equations. The results provide useful information on the dynamics of the relevant nonlinear negative-order equations.

  15. Impact Analysis of Aggraded Sediment on Dam-break Flood in Reservoir%某水库库区淤沙对溃坝洪水影响分析

    Institute of Scientific and Technical Information of China (English)

    郭维东; 康国亮; 胡志华; 谢方芳

    2011-01-01

    为分析某淤积型水库淤沙对溃坝洪水计算的影响,将MIKE21中的水动力模块与输沙模块耦合构建了二维溃坝水沙模型、分别模拟了不考虑淤沙与考虑淤沙运动水库的溃坝洪水演进过程.模拟结果表明,与不考虑淤沙运动水库溃坝相比,考虑淤沙的水库溃坝洪水下游各断面洪峰流量减小,洪水过后水位升高,水深变化不明显.%In order to analyze the influence of sediment in reservoir sedimentation on routing process of dam break flood, two-dimensional water-silt dam-break model is established by coupling hydrodynamic module (HD) and sand transport module (ST) in MIKE21 software. The dam-break flood routing process is simulated with or without considering the scouring and aggrading process of sediment in a reservoir. The results show that simulation considering the slit downstream sections have smaller peak flow discharge, lower water level after the dam break flood, water depth also changes in comparison with the simulation not considering the slit.

  16. An Experimental and Computational Study of Breaking Wave Impact Forces

    CERN Document Server

    Fu, Thomas C; Brewton, Susan; Brucker, Kyle A; Dommermuth, Douglas G

    2014-01-01

    The impact forces generated by the impact of a breaking wave are poorly understood. These impulsive hydrodynamic loads to a ship's hull are of short duration relative to ship motions and buoyant wave loads and often result in extremely high pressures. The physics of breaking waves is a poorly understood, complex, multiphase phenomenon involving violent jet sprays, strong free-surface turbulence, air entrainment and bubble generation, all of which interact with the flow field and the adjacent structure. This paper will describe a set of experiments that were performed, at the Naval Surface Warfare Center, Carderock Division (NSWCCD), in 2006, to measure the hydrodynamic loads of regular nonbreaking and focused breaking waves on a 0.305 m x 0.305 m (1.0 ft x 1.0 ft) square plate and discuss the results of this study. The paper will also discuss Computational Fluid Dynamics (CFD) code predictions of breaking waves and wave impact loads. The CFD code utilized in this study is Numerical Flow Analysis (NFA).

  17. Science Illiteracy: Breaking the Cycle

    Science.gov (United States)

    Lebofsky, L. A.; Lebofsky, N. R.

    2003-12-01

    At the University of Arizona, as at many state universities and colleges, the introductory science classes for non-science majors may be the only science classes that future K--8 teachers will take. The design of the UA's General Education program requires all future non-science certified teachers to take the General Education science classes. These classes are therefore an ideal venue for the training of the state's future teachers. Many students, often including future teachers, are ill-prepared for college, i.e., they lack basic science content knowledge, basic mathematics skills, and reading and writing skills. They also lack basic critical thinking skills and study skills. It is within this context that our future teachers are trained. How do we break the cycle of science illiteracy? There is no simple solution, and certainly not a one-size-fits-all panacea that complements every professor's style of instruction. However, there are several programs at the University of Arizona, and also principles that I apply in my own classes, that may be adaptable in other classrooms. Assessment of K--12 students' learning supports the use of inquiry-based science instruction. This approach can be incorporated in college classes. Modeling proven and productive teaching methods for the future teachers provides far more than ``just the facts,'' and all students gain from the inquiry approach. Providing authentic research opportunities employs an inquiry-based approach. Reading (outside the textbook) and writing provide feedback to students with poor writing and critical thinking skills. Using peer tutors and an instant messaging hot line gives experience to the tutors and offers "comfortable" assistance to students.

  18. Restructuring of an Event Tree for a Loss of Coolant Accident in a PSA model

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Ho-Gon; Han, Sang-Hoon; Park, Jin-Hee; Jang, Seong-Chul [KAERI, Daejeon (Korea, Republic of)

    2015-05-15

    Conventional risk model using PSA (probabilistic Safety Assessment) for a NPP considers two types of accident initiators for internal events, LOCA (Loss of Coolant Accident) and transient event such as Loss of electric power, Loss of cooling, and so on. Traditionally, a LOCA is divided into three initiating event (IE) categories depending on the break size, small, medium, and large LOCA. In each IE group, safety functions or systems modeled in the accident sequences are considered to be applicable regardless of the break size. However, since the safety system or functions are not designed based on a break size, there exist lots of mismatch between safety system/function and an IE, which may make the risk model conservative or in some case optimistic. Present paper proposes new methodology for accident sequence analysis for LOCA. We suggest an integrated single ET construction for LOCA by incorporating a safety system/function and its applicable break spectrum into the ET. Integrated accident sequence analysis in terms of ET for LOCA was proposed in the present paper. Safety function/system can be properly assigned if its applicable range is given by break set point. Also, using simple Boolean algebra with the subset of the break spectrum, final accident sequences are expressed properly in terms of the Boolean multiplication, the occurrence frequency and the success/failure of safety system. The accident sequence results show that the accident sequence is described more detailed compared with the conventional results. Unfortunately, the quantitative results in terms of MCS (minimal Cut-Set) was not given because system fault tree was not constructed for this analysis and the break set points for all 7 point were not given as a specified numerical quantity. Further study may be needed to fix the break set point and to develop system fault tree.

  19. Radiative Effects and Electroweak Symmetry Breaking in a Supersymmetric Preon Model

    Science.gov (United States)

    Kim, Jongbae

    We construct the low energy effective theory of composite quarks, leptons, and Higgs bosons for a supersymmetric preon model and study the effects of renormalization-group based radiative corrections. The study on the evolution of scalar masses for avoiding color and charge breakings leads us to conclude that Yukawa couplings are bounded from above. The implementation of electroweak symmetry breaking requires that only the purely dynamical symmetry breaking should be needed for the model, but the combined scheme of dynamical and radiative symmetry breaking as well as the purely radiative symmetry breaking scheme be disfavored. Our analysis of (mb)/(m_τ ) including radiative effects shows that, should a discrepancy be found between the observed and the theoretical value of (mb)/(m_τ ) after experimental determination of supersymmetric particle masses, it would imply that the complete quark-lepton universality in the supersymmetric preon model does not hold either for the Yukawa couplings, or for the condensates, or for both.

  20. Particle production from symmetry breaking after inflation

    CERN Document Server

    García-Bellido, J; Garcia-Bellido, Juan; Morales, Ester Ruiz

    2002-01-01

    Recent studies suggest that the process of symmetry breaking after inflation typically occurs very fast, within a single oscillation of the symmetry-breaking field, due to the spinodal growth of its long-wave modes, otherwise known as `tachyonic preheating'. In this letter we show how this sudden transition from the false to the true vacuum can induce a significant production of particles, bosons and fermions, coupled to the symmetry-breaking field. We find that this new mechanism of particle production in the early Universe may have interesting consequences for the origin of dark matter and the generation of the observed baryon asymmetry through leptogenesis.

  1. Break-Even Cost for Residential Photovoltaics in the United States: Key Drivers and Sensitivities

    Energy Technology Data Exchange (ETDEWEB)

    Denholm, P.; Margolis, R. M.; Ong, S.; Roberts, B.

    2009-12-01

    Grid parity--or break-even cost--for photovoltaic (PV) technology is defined as the point where the cost of PV-generated electricity equals the cost of electricity purchased from the grid. Break-even cost is expressed in $/W of an installed system. Achieving break-even cost is a function of many variables. Consequently, break-even costs vary by location and time for a country, such as the United States, with a diverse set of resources, electricity prices, and other variables. In this report, we analyze PV break-even costs for U.S. residential customers. We evaluate some key drivers of grid parity both regionally and over time. We also examine the impact of moving from flat to time-of-use (TOU) rates, and we evaluate individual components of the break-even cost, including effect of rate structure and various incentives. Finally, we examine how PV markets might evolve on a regional basis considering the sensitivity of the break-even cost to four major drivers: technical performance, financing parameters, electricity prices and rates, and policies. We find that local incentives rather than ?technical? parameters are in general the key drivers of the break-even cost of PV. Additionally, this analysis provides insight about the potential viability of PV markets.

  2. Interference in DNA replication can cause mitotic chromosomal breakage unassociated with double-strand breaks.

    Directory of Open Access Journals (Sweden)

    Mari Fujita

    Full Text Available Morphological analysis of mitotic chromosomes is used to detect mutagenic chemical compounds and to estimate the dose of ionizing radiation to be administered. It has long been believed that chromosomal breaks are always associated with double-strand breaks (DSBs. We here provide compelling evidence against this canonical theory. We employed a genetic approach using two cell lines, chicken DT40 and human Nalm-6. We measured the number of chromosomal breaks induced by three replication-blocking agents (aphidicolin, 5-fluorouracil, and hydroxyurea in DSB-repair-proficient wild-type cells and cells deficient in both homologous recombination and nonhomologous end-joining (the two major DSB-repair pathways. Exposure of cells to the three replication-blocking agents for at least two cell cycles resulted in comparable numbers of chromosomal breaks for RAD54(-/-/KU70(-/- DT40 clones and wild-type cells. Likewise, the numbers of chromosomal breaks induced in RAD54(-/-/LIG4(-/- Nalm-6 clones and wild-type cells were also comparable. These data indicate that the replication-blocking agents can cause chromosomal breaks unassociated with DSBs. In contrast with DSB-repair-deficient cells, chicken DT40 cells deficient in PIF1 or ATRIP, which molecules contribute to the completion of DNA replication, displayed higher numbers of mitotic chromosomal breaks induced by aphidicolin than did wild-type cells, suggesting that single-strand gaps left unreplicated may result in mitotic chromosomal breaks.

  3. Unconventional supersymmetry and its breaking

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, Pedro D., E-mail: alvarez@physics.ox.ac.uk [Centro de Estudios Científicos (CECS), Av. Arturo Prat 514, Valdivia (Chile); Universidad Andrés Bello, Av. República 440, Santiago (Chile); Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford (United Kingdom); Pais, Pablo, E-mail: pais@cecs.cl [Centro de Estudios Científicos (CECS), Av. Arturo Prat 514, Valdivia (Chile); Universidad Andrés Bello, Av. República 440, Santiago (Chile); Zanelli, Jorge, E-mail: z@cecs.cl [Centro de Estudios Científicos (CECS), Av. Arturo Prat 514, Valdivia (Chile); Universidad Andrés Bello, Av. República 440, Santiago (Chile)

    2014-07-30

    We present a gauge theory for a superalgebra that includes an internal gauge (G) and local Lorentz (so(1,D−1)) algebras. These two symmetries are connected by fermionic supercharges. The field content of the system includes a (non-)abelian gauge potential A, a spin-1/2 Dirac spinor ψ, the Lorentz connection ω{sup ab}, and the vielbein e{sub μ}{sup a}. The connection one-form A is in the adjoint representation of G, while ψ is in the fundamental. In contrast to standard supersymmetry and supergravity, the metric is not a fundamental field and is in the center of the superalgebra: it is not only invariant under the internal gauge group, G, and under Lorentz transformations, SO(1,D−1), but is also invariant under supersymmetry. The distinctive features of this theory that mark the difference with standard supersymmetries are: i) the number of fermionic and bosonic states is not necessarily the same; ii) there are no superpartners with equal mass; iii) although this supersymmetry originates in a local gauge theory and gravity is included, there is no gravitino; iv) fermions acquire mass from their coupling to the background or from higher order self-couplings, while bosons remain massless. In odd dimensions, the Chern–Simons (CS) form provides an action that is (quasi-)invariant under the entire superalgebra. In even dimensions, the Yang–Mills (YM) form is the only natural option and the symmetry breaks down to G⊗SO(1,D−1). In four dimensions, the construction follows the Townsend–Mac Dowell–Mansouri approach, starting with an osp(4|2)∼usp(2,2|1) connection. Due to the absence of osp(4|2)-invariant traces in four dimensions, the resulting Lagrangian is only invariant under u(1)⊕so(3,1), which includes a Nambu–Jona-Lasinio (NJL) term. In this case, the Lagrangian depends on a single dimensionful parameter that fixes Newton's constant, the cosmological constant and the NJL coupling.

  4. Symmetry Breaking for Answer Set Programming

    CERN Document Server

    Drescher, Christian

    2010-01-01

    In the context of answer set programming, this work investigates symmetry detection and symmetry breaking to eliminate symmetric parts of the search space and, thereby, simplify the solution process. We contribute a reduction of symmetry detection to a graph automorphism problem which allows to extract symmetries of a logic program from the symmetries of the constructed coloured graph. We also propose an encoding of symmetry-breaking constraints in terms of permutation cycles and use only generators in this process which implicitly represent symmetries and always with exponential compression. These ideas are formulated as preprocessing and implemented in a completely automated flow that first detects symmetries from a given answer set program, adds symmetry-breaking constraints, and can be applied to any existing answer set solver. We demonstrate computational impact on benchmarks versus direct application of the solver. Furthermore, we explore symmetry breaking for answer set programming in two domains: firs...

  5. Water Breaking: Understand This Sign of Labor

    Science.gov (United States)

    Healthy Lifestyle Labor and delivery, postpartum care Water breaking worries? Prepare yourself for childbirth by getting the facts about this important sign of labor. By Mayo Clinic Staff If you're ...

  6. Breaking antidunes: Cyclic behavior due to hysteresis

    DEFF Research Database (Denmark)

    Deigaard, Rolf

    2006-01-01

    The cyclic behavior of breaking antidunes (growth, breaking of surface wave, obliteration) is investigated by use of a numerical model. The model includes the transition between supercritical and transcritical flow. As the antidune grows the flow becomes transcritical and a hydraulic jump is form...... upstream of the antidune crest. The relation between growth of the antidune and supercritical flow and between decay and transcritical flow is shown, and the significance of hysteresis in the flow conditions is investigated....

  7. Symmetry Breaking and Second Order Phase Transitions

    Institute of Scientific and Technical Information of China (English)

    ZhangFengshou; R.M.Lynden-Bell

    2003-01-01

    In an earlier paper we showed that symmetry breaking could be induced in the triiodide ion by varying the solvent. Experiments and simulations suggest that protic solvents which can form hydrogen bonds with a negative ion cause symmetry breaking of the ion, so that the charge becomes concentrated at one end of the ion and the corresponding bond elongates. We suggested that one could draw an analogy between the mean field Ising model with free energy,

  8. Dynamical supersymmetry breaking and unification of couplings

    CERN Document Server

    Dubovsky, S L; Troitsky, S V

    1997-01-01

    We consider the possibility of unification of the Supersymmetric Standard Model gauge groups with those of the dynamical supersymmetry breaking (DSB) sector in theories with gauge mediated supersymmetry breaking. We find constraints on the DSB gauge group beta function that come from unification of the gauge coupling constants of the two sectors. These constraints are satisfied by a fairly wide class of models. We discuss possible unification scenarios in the context of a simple model.

  9. Dormancy Breaking in Ormosia arborea Seeds

    OpenAIRE

    Edilma Pereira Gonçalves; Franklim Sales de Jesus Soares; Sérgio dos Santos Silva; Débora de Souza Tavares; Jeandson Silva Viana; Brenda Colleen Clifton Cardoso

    2011-01-01

    Ormosia arborea is a tree species planted in urban areas and used to restore degraded areas. Its seeds are dormant and propagation is difficult. This study compares different dormancy breaking methods and physiological seed quality and seedling production. The seeds were germinated in sand in the laboratory of the Universidade Estadual de Santa Cruz, Ilhéus, Bahia, Brazil. The following dormancy breaking treatments were applied: control (intact seeds), 100°C water immersion; boiling water imm...

  10. Is soft breaking of BRST symmetry consistent?

    CERN Document Server

    Lavrov, Peter; Reshetnyak, Alexander

    2011-01-01

    A definition of soft breaking of BRST symmetry in the field-antifield formalism is proposed, valid for general gauge theories and arbitrary gauge fixing. The Ward identities for the generating functionals of Green's functions are derived, and their gauge dependence is investigated. We present a generalization of the Gribov-Zwanziger action to a one-parameter linear gauge. It is argued that gauge theories with a soft breaking of BRST symmetry are inconsistent.

  11. String breaking in two-dimensional QCD

    CERN Document Server

    Hornbostel, K J

    1999-01-01

    I present results of a numerical calculation of the effects of light quark-antiquark pairs on the linear heavy-quark potential in light-cone quantized two-dimensional QCD. I extract the potential from the Q-Qbar component of the ground-state wavefunction, and observe string breaking at the heavy-light meson pair threshold. I briefly comment on the states responsible for the breaking.

  12. Phil Anderson and Gauge Symmetry Breaking

    Science.gov (United States)

    Witten, Edward

    In this article, I describe the celebrated paper that Phil Anderson wrote in 1962 with early contributions to the idea of gauge symmetry breaking in particle physics. To set the stage, I describe the work of Julian Schwinger to which Anderson was responding, and also some of Anderson's own work on superconductivity that provided part of the context. After describing Anderson's work I describe the later work of others, leading to the modern understanding of gauge symmetry breaking in weak interactions...

  13. Kinematic criterion for breaking of shoaling waves

    Science.gov (United States)

    Liberzon, Dan; Itay, Uri

    2016-11-01

    Validity of a kinematic criterion for breaking of shoaling waves was examined experimentally. Results obtained by simultaneous measurements of water surface velocity by PTV and of the propagation velocity of a steep crest up to the point of breaking inception during shoaling will be reported. The experiments performed in a large wave tank examining breaking behavior of gentle spillers during shoaling on three different slopes suggest a validity of the recently proposed kinematic criterion. The breaking inception was found to occur when the horizontal velocity of the water surface on the steep (local steepness of 0.41-0.6) crest reaches a threshold value of 0.85-0.95 of that of the crest propagation. The exact moment and position of breaking inception detected using a Phase Time Method (PTM), characterizing a unique shape of the local frequency fluctuations at the inception. Future implementation of the PTM method for detection of breaking events in irregular wave fields will be discussed. Supported by German-Israeli Foundation for Scientific Research and Development (GIF) Grant #2019392.

  14. Warp Breaks Detection in Jacquard Weaving Using MEMS: Effect of Weave on Break Signals

    Directory of Open Access Journals (Sweden)

    Jin H Lee, Ph.D.

    2008-03-01

    Full Text Available This paper reports a study to detect warp breaks in terms of weave structure using MEMS accelerometer based detection system. The system is briefly described. The output signals of MEMS sensors, which were mounted on harness cords of a Jacquard machine, at the moment of warp yarn break and after the break for a broad range of basic weaves were acquired during weaving. The weaves investigated are commonly used in Jacquard weaving to form patterns. The strength of the MEMS output acceleration signals was analyzed in time domain. The results show that the system is capable of detecting warp yarn breaks for the broad range of weaves studied.

  15. Review of factorization breaking in diffractive photoproduction of dijets

    CERN Document Server

    Klasen, M

    2008-01-01

    After the final analyses of the H1 and ZEUS collaborations for the diffractive photoproduction of dijets have appeared, we have recalculated these cross sections in next-to-leading order (NLO) of perturbative QCD to see whether they can be interpreted consistently. The results of these calculations are compared to the data of both collaborations. We find that at NLO the cross sections disagree with the data, showing that factorization breaking occurs at this order. If direct and resolved contributions are both suppressed by the same amount, the global suppression factor depends on the transverse-energy cut and is 0.42 for the H1 and 0.71 for the ZEUS analysis. However, by suppressing only the resolved contribution by a factor of approximately three, also reasonably good agreement with all the data is found. The size of the factorization breaking effects for resolved photons agrees with absorptive-model predictions.

  16. Review of factorization breaking in diffractive photoproduction of dijets

    Energy Technology Data Exchange (ETDEWEB)

    Klasen, Michael [Grenoble Univ. (France). Lab. de Physique Subatomique et de Cosmologie; Kramer, Gustav [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2008-06-13

    After the final analyses of the H1 and ZEUS collaborations for the diffractive photoproduction of dijets have appeared, we have recalculated these cross sections in next-to-leading order (NLO) of perturbative QCD to see whether they can be interpreted consistently. The results of these calculations are compared to the data of both collaborations. We find that at NLO the cross sections disagree with the data, showing that factorization breaking occurs at this order. If direct and resolved contributions are both suppressed by the same amount, the global suppression factor depends on the transverse energy cut and is 0.42 for the H1 and 0.71 for the ZEUS analysis. However, by suppressing only the resolved contribution by a factor of approximately three, also reasonably good agreement with all the data is found. The size of the factorization breaking effects for resolved photons agrees with absorptive-model predictions. (orig.)

  17. Review of Factorization Breaking in Diffractive Photoproduction of Dijets

    Science.gov (United States)

    Klasen, Michael; Kramer, Gustav

    After the final analyses of the H1 and ZEUS collaborations for the diffractive photoproduction of dijets have appeared, we have recalculated these cross sections in next-to-leading order (NLO) of perturbative QCD to see whether they can be interpreted consistently. The results of these calculations are compared to the data of both collaborations. We find that at NLO the cross sections disagree with the data, showing that factorization breaking occurs at this order. If direct and resolved contributions are both suppressed by the same amount, the global suppression factor depends on the transverse-energy cut and is 0.42 for the H1 and 0.71 for the ZEUS analysis. However, by suppressing only the resolved contribution by a factor of approximately three, also reasonably good agreement with all the data is found. The size of the factorization breaking effects for resolved photons agrees with absorptive-model predictions.

  18. Note on moduli stabilization, supersymmetry breaking and axiverse

    Energy Technology Data Exchange (ETDEWEB)

    Higaki, Tetsutaro [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kobayashi, Tatsuo [Kyoto Univ. (Japan). Dept. of Physics

    2011-06-15

    We study properties of moduli stabilization in the four dimensional N=1 supergravity theory with heavy moduli and would-be saxion-axion multiplets including light string-theoretic axions. We give general formulation for the scenario that heavy moduli and saxions are stabilized while axions remain light, assuming that moduli are stabilized near the supersymmetric solution. One can find stable vacuum, i.e. nontachyonic saxions, in the non-supersymmetric Minkowski vacua. We also discuss the cases, where the moduli are coupled to the supersymmetry breaking sector and/or moduli have contributions to supersymmetry breaking. Furthermore we study the models with axions originating from matter-like fields. Our analysis on moduli stabilization is applicable even if there are not light axion multiplets. (orig.)

  19. Nonlinear wave breaking in self-gravitating viscoelastic quantum fluid

    Science.gov (United States)

    Mitra, Aniruddha; Roychoudhury, Rajkumar; Bhar, Radhaballav; Khan, Manoranjan

    2017-02-01

    The stability of a viscoelastic self-gravitating quantum fluid has been studied. Symmetry breaking instability of solitary wave has been observed through 'viscosity modified Ostrovsky equation' in weak gravity limit. In presence of strong gravitational field, the solitary wave breaks into shock waves. Response to a Gaussian perturbation, the system produces quasi-periodic short waves, which in terns predicts the existence of gravito-acoustic quasi-periodic short waves in lower solar corona region. Stability analysis of this dynamical system predicts gravity has the most prominent effect on the phase portraits, therefore, on the stability of the system. The non-existence of chaotic solution has also been observed at long wavelength perturbation through index value theorem.

  20. MM98.19 An automatic system for elaboration of chip breaking diagrams

    DEFF Research Database (Denmark)

    Andreasen, Jan Lasson; Chiffre, Leonardo De

    1998-01-01

    A laboratory system for fully automatic elaboration of chip breaking diagrams has been developed and tested. The system is based on automatic chip breaking detection by frequency analysis of cutting forces in connection with programming of a CNC-lathe to scan different feeds, speeds and cutting...... depths. An evaluation of the system based on a total of 1671 experiments has shown that unfavourable snarled chips can be detected with 98% certainty which indeed makes the system a valuable tool in chip breakability tests. Using the system, chip breaking diagrams can be elaborated with a previously...

  1. Jet simulations and gamma-ray burst afterglow jet breaks

    NARCIS (Netherlands)

    van Eerten, H. J.; Meliani, Z.; Wijers, R.A.M.J.; Keppens, R.

    2010-01-01

    The conventional derivation of the gamma-ray burst afterglow jet break time uses only the blast wave fluid Lorentz factor and therefore leads to an achromatic break. We show that in general gamma-ray burst afterglow jet breaks are chromatic across the self-absorption break. Depending on circumstance

  2. Jet simulations and gamma-ray burst afterglow jet breaks

    NARCIS (Netherlands)

    van Eerten, H. J.; Meliani, Z.; Wijers, Ramj; Keppens, R.

    2011-01-01

    The conventional derivation of the gamma-ray burst afterglow jet break time uses only the blast wave fluid Lorentz factor and therefore leads to an achromatic break. We show that in general gamma-ray burst afterglow jet breaks are chromatic across the self-absorption break. Depending on circumstance

  3. Jet simulations and gamma-ray burst afterglow jet breaks

    NARCIS (Netherlands)

    van Eerten, H.J.; Meliani, Z.; Wijers, R.A.M.J.; Keppens, R.

    2012-01-01

    The conventional derivation of the gamma-ray burst afterglow jet break time uses only the blast wave fluid Lorentz factor and therefore leads to an achromatic break. We show that in general gamma-ray burst afterglow jet breaks are chromatic across the self-absorption break. Depending on circumstance

  4. 失水事故工况下主泵全特性数值分析%Numerical Analysis on Complete Characteristics of LOCA Reactor Coolant Pump

    Institute of Scientific and Technical Information of China (English)

    付强; 龙云; 朱荣生; 袁寿其; 习毅

    2014-01-01

    为研究核反应堆主冷却剂泵在失水事故工况下的全特性,通过三维软件Pro/E对核主泵内部流道进行三维造型,利用雷诺时均N-S方程和RNGk-ε两方程及SIMPLEC算法,应用计算流体力学软件(CFX)对核主泵全特性进行数值模拟计算,分析核反应堆主冷却剂泵的全特性曲线,并解释小流量出现驼峰现象的原因.结果表明:叶轮所受的扭矩主要来自于叶片所受的扭矩,前后盖板所受的扭矩对叶轮的影响很小.叶片所受的扭矩和轴向力的变化趋势和流量-扬程曲线变化规律有一定的相似性,三者之间可能有密切关系.

  5. Distributions of Low- and High-LET Radiation-Induced Breaks in Chromosomes are Associated with Inter- and Intrachromosome Exchanges

    Science.gov (United States)

    Hada, Megumi; Zhang, Ye; Feiveson, Alan; Cucinotta, Francis A.; Wu, Honglu

    2010-01-01

    To study the breakpoint along the length of the chromosome induced by low- and high-LET radiations, we exposed human epithelial cells in vitro to Cs-137 rays at both low and high dose rates, secondary neutrons at a low dose rate, and 600 MeV/u Fe ions at a high dose rate. The location of the breaks was identified using the multicolor banding in situ hybridization (mBAND) that paints Chromosome 3 in 23 different colored bands. The breakpoint distributions were found to be similar between rays of low and high dose rates and between the two high-LET radiation types. Detailed analysis of the chromosome break ends involved in inter- and intrachromosome exchanges revealed that only the break ends participating in interchromosome exchanges contributed to the hot spots found for low-LET. For break ends participating in intrachromosome exchanges, the distributions for all four radiation scenarios were similar with clusters of breaks found in three regions. Analysis of the locations of the two break ends in Chromosome 3 that joined to form an intrachromosome exchange demonstrated that two breaks with a greater genomic separation may be more likely to rejoin than two closer breaks, indicating that chromatin folding can play an important role in the rejoining of chromosome breaks. Our study demonstrated that the gene-rich regions do not necessarily contain more breaks. The breakpoint distribution depends more on the likelihood that a break will join with another break in the same chromosome or in a different chromosome.

  6. Methodology of a PWR containment analysis during a thermal-hydraulic accident

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Dayane F.; Sabundjian, Gaiane; Lima, Ana Cecilia S., E-mail: dayane.silva@usp.br, E-mail: gdjian@ipen.br, E-mail: aclima@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    The aim of this work is to present the methodology of calculation to Angra 2 reactor containment during accidents of the type Loss of Coolant Accident (LOCA). This study will be possible to ensure the safety of the population of the surroundings upon the occurrence of accidents. One of the programs used to analyze containment of a nuclear plant is the CONTAIN. This computer code is an analysis tool used for predicting the physical conditions and distributions of radionuclides inside a containment building following the release of material from the primary system in a light-water reactor during an accident. The containment of the type PWR plant is a concrete building covered internally by metallic material and has limits of design pressure. The methodology of containment analysis must estimate the limits of pressure during a LOCA. The boundary conditions for the simulation are obtained from RELAP5 code. (author)

  7. Shock Geometry and Spectral Breaks in Large SEP Events

    Science.gov (United States)

    Li, G.; Zank, G. P.; Verkhoglyadova, Olga; Mewaldt, R. A.; Cohen, C. M. S.; Mason, G. M.; Desai, M. I.

    2009-09-01

    Solar energetic particle (SEP) events are traditionally classified as "impulsive" or "gradual." It is now widely accepted that in gradual SEP events, particles are accelerated at coronal mass ejection-driven (CME-driven) shocks. In many of these large SEP events, particle spectra exhibit double power law or exponential rollover features, with the break energy or rollover energy ordered as (Q/A)α, with Q being the ion charge in e and A the ion mass in units of proton mass mp . This Q/A dependence of the spectral breaks provides an opportunity to study the underlying acceleration mechanism. In this paper, we examine how the Q/A dependence may depend on shock geometry. Using the nonlinear guiding center theory, we show that α ~ 1/5 for a quasi-perpendicular shock. Such a weak Q/A dependence is in contrast to the quasi-parallel shock case where α can reach 2. This difference in α reflects the difference of the underlying parallel and perpendicular diffusion coefficients κ|| and κbottom. We also examine the Q/A dependence of the break energy for the most general oblique shock case. Our analysis offers a possible way to remotely examine the geometry of a CME-driven shock when it is close to the Sun, where the acceleration of particle to high energies occurs.

  8. Symmetry-breaking instability in a prototypical driven granular gas.

    Science.gov (United States)

    Khain, Evgeniy; Meerson, Baruch

    2002-08-01

    Symmetry-breaking instability of a laterally uniform granular cluster (strip state) in a prototypical driven granular gas is investigated. The system consists of smooth hard disks in a two-dimensional box, colliding inelastically with each other and driven, at zero gravity, by a "thermal" wall. The limit of nearly elastic particle collisions is considered, and granular hydrodynamics with the Jenkins-Richman constitutive relations is employed. The hydrodynamic problem is completely described by two scaled parameters and the aspect ratio of the box. Marginal stability analysis predicts a spontaneous symmetry-breaking instability of the strip state, similar to that predicted recently for a different set of constitutive relations. If the system is big enough, the marginal stability curve becomes independent of the details of the boundary condition at the driving wall. In this regime, the density perturbation is exponentially localized at the elastic wall opposite the thermal wall. The short- and long-wavelength asymptotics of the marginal stability curves are obtained analytically in the dilute limit. The physics of the symmetry-breaking instability is discussed.

  9. Workshop on electroweak symmetry breaking: proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Hinchliffe, I. (ed.)

    1984-10-01

    A theoretical workshop on electroweak symmetry breaking at the Superconducting Supercollider was held at Lawrence Berkeley Laboratory, June 4-22, 1984. The purpose of the workshop was to focus theoretical attention on the ways in which experimentation at the SSC could reveal manifestations of the phenomenon responsible for electroweak symmetry breaking. This issue represents, at present, the most compelling scientific argument for the need to explore the energy region to be made accessible by the SSC, and a major aim of the workshop was to involve a broad cross section of particle theorists in the ongoing process of sharpening the requirements for both accelerator and detector design that will ensure detection and identification of meaningful signals, whatever form the electroweak symmetry breaking phenomenon should actually take. Separate entries were prepared for the data base for the papers presented.

  10. Isospin Breaking Effects on the Lattice

    CERN Document Server

    Tantalo, Nazario

    2013-01-01

    Isospin symmetry is not exact and the corrections to the isosymmetric limit are, in general, at the percent level. For gold plated quantities, such as pseudoscalar meson masses or the kaon leptonic and semileptonic decay rates, these effects are of the same order of magnitude of the errors quoted in nowadays lattice calculations and cannot be neglected any longer. In this talk I discuss the methods that have been developed in the last few years to calculate isospin breaking corrections by starting from first principles lattice simulations. In particular, I discuss how to perform a combined QCD+QED lattice simulation and a renormalization prescription to be used in order to separate QCD from QED isospin breaking effects. A brief review of recent lattice results of isospin breaking effects on the hadron spectrum is also included.

  11. Large eddy simulation of breaking waves

    DEFF Research Database (Denmark)

    Christensen, Erik Damgaard; Deigaard, Rolf

    2001-01-01

    is described by large eddy simulation where the larger turbulent features are simulated by solving the flow equations, and the small scale turbulence that is not resolved by the flow model is represented by a sub-grid model. A simple Smagorinsky sub-grid model has been used for the present simulations......A numerical model is used to simulate wave breaking, the large scale water motions and turbulence induced by the breaking process. The model consists of a free surface model using the surface markers method combined with a three-dimensional model that solves the flow equations. The turbulence....... The incoming waves are specified by a flux boundary condition. The waves are approaching in the shore-normal direction and are breaking on a plane, constant slope beach. The first few wave periods are simulated by a two-dimensional model in the vertical plane normal to the beach line. The model describes...

  12. Breaking bad news in cancer patients

    Directory of Open Access Journals (Sweden)

    Apostolos Konstantis

    2015-01-01

    Full Text Available Objective: In a regional hospital, many patients are newly diagnosed with cancer. Breaking the bad news in these patients and their relatives is a tough task. Many doctors are not experienced in talking to patients about death or death-related diseases. In recent years, there have been great efforts to change the current situation. The aim of this study was to investigate the experience and education of medical personnel in breaking bad news in a secondary hospital. Materials and Methods: 59 doctors from General Hospital of Komotini, Greece were included in the study. All the doctors were in clinical specialties that treated cancer patients. A brief questionnaire was developed based on current guidelines such as Baile/SPIKES framework and the ABCDE mnemonic. Results: Residents are involved in delivering bad news less frequently than specialists. Only 21 doctors (35.59% had specific training on breaking bad news. 20 doctors (33.90% were aware of the available techniques and protocols on breaking bad news. 47 doctors (79.66% had a consistent plan for breaking bad news. 57 (96.61% delivered bad news in a quiet place, 53 (89.83% ensured no interruptions and enough time, 53 (89.83% used simple words and 54 (91.53% checked for understanding and did not rush through the news. 46 doctors (77.97% allowed relatives to determine patient′s knowledge about the disease. Conclusions: There were low rates of specific training in breaking bad news. However, the selected location, the physician′s speech and their plan were according to current guidelines.

  13. Breaking Bad News in Cancer Patients

    Science.gov (United States)

    Konstantis, Apostolos; Exiara, Triada

    2015-01-01

    Objective: In a regional hospital, many patients are newly diagnosed with cancer. Breaking the bad news in these patients and their relatives is a tough task. Many doctors are not experienced in talking to patients about death or death-related diseases. In recent years, there have been great efforts to change the current situation. The aim of this study was to investigate the experience and education of medical personnel in breaking bad news in a secondary hospital. Materials and Methods: 59 doctors from General Hospital of Komotini, Greece were included in the study. All the doctors were in clinical specialties that treated cancer patients. A brief questionnaire was developed based on current guidelines such as Baile/SPIKES framework and the ABCDE mnemonic. Results: Residents are involved in delivering bad news less frequently than specialists. Only 21 doctors (35.59%) had specific training on breaking bad news. 20 doctors (33.90%) were aware of the available techniques and protocols on breaking bad news. 47 doctors (79.66%) had a consistent plan for breaking bad news. 57 (96.61%) delivered bad news in a quiet place, 53 (89.83%) ensured no interruptions and enough time, 53 (89.83%) used simple words and 54 (91.53%) checked for understanding and did not rush through the news. 46 doctors (77.97%) allowed relatives to determine patient's knowledge about the disease. Conclusions: There were low rates of specific training in breaking bad news. However, the selected location, the physician's speech and their plan were according to current guidelines. PMID:25709183

  14. 船用交流中压断路器开断性能相关参数分析%Analysis of Parameters for Breaking Performance of Marine Medium Voltage AC Circuit Breakers

    Institute of Scientific and Technical Information of China (English)

    杨青

    2013-01-01

    According to the characteristics of marine medium voltage power system,the parameters closely related to the breaking performance of medium voltage AC circuit breaker were analyzed.It is shown that the key performance parameters in land standards,such as rated breaking current,making current,power frequency recovery voltage,transient recovery voltage,electrical life and so on,basically meet the marine requirements after conversion. But there are also some individual parameters need to be studied further to decide.%根据船舶中压电力系统的特点,对中压断路器开断性能密切相关的参数进行了分析。结果表明,陆用标准中额定短路开断电流和关合电流、工频恢复电压和瞬态恢复电压、电寿命等参数经过换算、折算,基本上符合船用要求,个别参数是否合适有待进一步研究。

  15. Gauge mediated supersymmetry breaking and neutrino anomalies

    CERN Document Server

    Joshipura, A S; Joshipura, Anjan S.; Vempati, Sudhir K.

    1999-01-01

    Supersymmetric standard model with softly broken lepton symmetry provides a suitable framework to accommodate the solar and atmospheric neutrino anomalies. This model contains a natural explanation for large mixing and hierarchal masses without fine tuning of the parameters. Neutrino spectrum is particularly constrained in the minimal messenger model (MMM) of gauge mediated SUSY breaking, since all SUSY breaking effects are controlled in MMM by a single parameter. We study the structure of neutrino masses and mixing both in MMM and in simple extensions of it in the context of solar and atmospheric neutrino anomalies.

  16. Breaking the cycle of family violence

    OpenAIRE

    Heikkinen, Eeva

    2009-01-01

    ABSTRACT Heikkinen Eeva. Breaking the cycle of family violence. Järvenpää, Autumn 2009, 51 pages, 2 appendices. Diaconia University of Applied Sciences, Diak South, Järvenpää. Degree Programme in Social Services. The research was done in a shelter for battered family members, a place where families can go, when they are unable to stay at home because of violence. The aim of the research was to find out the role of the shelter in breaking the cycle of family violence and to ...

  17. Dynamical Symmetry Breaking in Warped Compactifications

    CERN Document Server

    Rius, N

    2001-01-01

    We study dynamical electroweak symmetry breaking in the Randall-Sundrum scenario. We show that one extra dimension is enough to give the correct pattern of electroweak symmetry breaking in a simple model with gauge bosons and the right-handed top quark in the bulk. The top quark mass is also in agreement with experiment. Furthermore, we propose an extended scenario with all Standard Model gauge bosons and fermions propagating in the bulk, which naturally accommodates the fermion mass hierarchies. No new fields or interactions beyond the observed in the Standard Model are required.

  18. Factorization breaking in diffractive dijet photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Klasen, M. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik]|[Centre National de la Recherche Scientifique, 38 - Grenoble (France). Univ. Joseph Fourier, Lab. de Physique Subatomique et de Cosmologie; Kramer, G. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2004-08-01

    We have calculated the diffractive dijet cross section in low-Q{sup 2} ep scattering in the HERA regime. The results of the calculation in LO and NLO are compared to recent experimental data of the H1 collaboration. We find that in LO the calculated cross sections are in reasonable agreement with the experimental results. In NLO, however, some of the cross sections disagree, showing that factorization breaking occurs in that order. By suppressing the resolved contribution by a factor of approximately three, good agreement with all the data is found. The size of the factorization breaking effects in diffractive dijet photoproduction agrees well with absorptive model predictions. (orig.)

  19. Factorization breaking in diffractive dijet photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Klasen, M. [Universite Joseph Fourier, CNRS-IN2P3, Laboratoire de Physique Subatomique et de Cosmologie, Grenoble (France); Universitaet Hamburg, II. Institut fuer Theoretische Physik, Hamburg (Germany); Kramer, G. [Universitaet Hamburg, II. Institut fuer Theoretische Physik, Hamburg (Germany)

    2004-12-01

    We have calculated the diffractive dijet cross section in low-Q{sup 2} ep scattering in the HERA regime. The results of the calculation in LO and NLO are compared to recent experimental data of the H1 Collaboration. We find that in LO the calculated cross sections are in reasonable agreement with the experimental results. In NLO, however, some of the cross sections disagree, showing that factorization breaking occurs in that order. By suppressing the resolved contribution by a factor of approximately three, good agreement with all the data is found. The size of the factorization breaking effects in diffractive dijet photoproduction agrees well with absorptive model predictions. (orig.)

  20. Effective dissipation: breaking time-reversal symmetry

    CERN Document Server

    Brown, Aidan I

    2016-01-01

    At molecular scales, fluctuations play a significant role and prevent biomolecular processes from always proceeding in a preferred direction, raising the question of how limited amounts of free energy can be dissipated to obtain directed progress. We examine the system and process characteristics that efficiently break time-reversal symmetry at fixed energy loss; in particular for a simple model of a molecular machine, an intermediate energy barrier produces unusually high asymmetry for a given dissipation. Such insight into symmetry-breaking factors that produce particularly high time asymmetry suggests generalizations to a broader class of systems.

  1. Mediation of supersymmetry breaking in extra dimensions

    CERN Document Server

    Scrucca, C A

    2004-01-01

    I review the mechanisms of supersymmetry breaking mediation that occur in sequestered models, where the visible and the hidden sectors are separated by an extra dimension and communicate only via gravitational interactions. By locality, soft breaking terms are forbidden at the classical level and reliably computable within an effective field theory approach at the quantum level. I present a self-contained discussion of these radiative gravitational effects and the resulting pattern of soft masses, and give an overview of realistic model building based on this set-up. I consider both flat and warped extra dimensions, as well as the possibility that there be localized kinetic terms for the gravitational fields.

  2. Numerical Study on Breaking Criteria for Solitary Waves

    Institute of Scientific and Technical Information of China (English)

    Chung-ren CHOU; Ruey-syan SHIH; John Z. YIM

    2003-01-01

    Studies of the breaking criteria for solitary waves on a slope are presented in this paper. The boundary element method is used to model the processes of shoaling and breaking of solitary waves on various slopes. Empirical formulae that can be used to characterize the breaking of solitary waves are presented. These include the breaking index, the wave height, the water depth, and the maximum particle velocity at the point of breaking. Comparisons with the results of other researches are given.

  3. [Analysis on the sensitivity to beta-lactam antibiotics of respiratory-infectious isolates on the second survey on the sensitivity of isolates conducted by the Japanese Society of Chemotherapy in 2007--concerning the aspect of PK/PD break points].

    Science.gov (United States)

    Niki, Yoshihito; Kohno, Shigeru; Watanabe, Akira; Aoki, Nobuki

    2009-06-01

    Sensitivity to beta-lactam antibiotics of isolates clinically obtained from respiratory infection sites in adults on the second survey on sensitivity of isolates conducted by the Japanese Society of Chemotherapy in 2007 was investigated according to the classification of the "Guideline for treatment for adult nosocomial pneumonia in 2008". Among the primary antibacterial drugs for mild (A) and moderate (B) nosocomial pneumonia in adults, beta-lactam antibiotics; ceftriaxone (CTRX), sulbactam/ampicillin (SBT/ABPC), panipenem/betamipron (PAPM/BP), tazobactam/piperacillin (TAZ/PIPC), imipenem/cilastatin (IPM/CS), meropenem (MEPM), doripenem (DRPM), biapenem (BIPM) were studied to evaluate their clinical efficacy. The covering rate was analyzed using the minimal inhibitory concentration (MIC) and break point of pharmacokinetics/pharmacodynamics (PK/PD). Consequently, the results with methicillin-susceptible Staphylococcus aureus (MSSA), Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Klebsiella pneumoniae revealed the MIC90 of all antibacterial drugs to be at low levels, while almost 100% of isolates were within the range of PK/PD break points except BIPM and SBT/ABPC to H. influenzae, and SBT/ABPC to K. pneumoniae. However, the analysis of P. aeruginosa didn't reach 100% for the covering rates of isolates, indicating that these drugs did not have a complete inhibitory action to restrict bacterial proliferation. The analysis of all 5 carbapenem drugs showed superiority to TAZ/PIPC in MIC90 while covering rates of isolates at PK/PD break points showed inferiority to TAZ/PIPC. This tendency was found to be more significant in covering the rates of isolates on the regular dose with maximal bactericidal action and on the maximum dose. This is because the maximum dose approved in Japan is as low as half that in IPM/CS and 1/3 that in MEPM in Western countries.

  4. Determining Industrial Comparative Advantages in Areas of Proposed Water Navigation Projects: An Industrial Location Analysis.

    Science.gov (United States)

    1981-12-01

    used in analyzing industrial loca- tions. Since there are a number of adequate summaries of these techni- ques (see Isard [3]), no attempt will be...use of these techniques in conjunction with other techniques, the reader is referred to Isard [31. 4.3 Correlation and Regression Analysis In a major...1978 2. Greenhut, Melvin L., Plant Location in Theory and in Practice, The University of North Carolina Press, 1956 3. Isard , Walter, Methods of Regional

  5. Human Amebiasis: Breaking the Paradigm?

    Directory of Open Access Journals (Sweden)

    Oswaldo Partida

    2010-03-01

    Full Text Available For over 30 years it has been established that the Entamoeba histolytica protozoan included two biologically and genetically different species, one with a pathogenic phenotype called E. histolytica and the other with a non-pathogenic phenotype called Entamoeba dispar. Both of these amoebae species can infect humans. E. histolytica has been considered as a potential pathogen that can cause serious damage to the large intestine (colitis, dysentery and other extraintestinal organs, mainly the liver (amebic liver abscess, whereas E. dispar is a species that interacts with humans in a commensal relationship, causing no symptoms or any tissue damage. This paradigm, however, should be reconsidered or re-evaluated. In the present work, we report the detection and genotyping of E. dispar sequences of DNA obtained from patients with amebic liver abscesses, including the genotyping of an isolate obtained from a Brazilian patient with a clinical diagnosis of intestinal amebiasis that was previously characterized as an E. dispar species. The genetic diversity and phylogenetic analysis performed by our group has shown the existence of several different genotypes of E. dispar that can be associated to, or be potentiality responsible for intestinal or liver tissue damage, similar to that observed with E. histolytica.

  6. Supersymmetry and R-symmetry Breaking in Meta-stable Vacua at Finite Temperature and Density

    CERN Document Server

    Arai, Masato; Sasaki, Shin

    2014-01-01

    We study a meta-stable supersymmetry-breaking vacuum in a generalized O'Raifeartaigh model at finite temperature and chemical potentials. Fields in the generalized O'Raifeartaigh model possess different R-charges to realize R-symmetry breaking. Accordingly, at finite density and temperature, the chemical potentials have to be introduced in a non-uniform way. Based on the formulation elaborated in our previous work we study the one-loop thermal effective potential including the chemical potentials in the generalized O'Raifeartaigh model. We perform the numerical analysis and find that the R-symmetry breaking vacua, which exist at zero temperature and zero chemical potential, are destabilized for some parameter regions. In addition, we find that there are parameter regions where new R-symmetry breaking vacua are realized even at high temperature by the finite density effects.

  7. Path-breaking books in regional science

    NARCIS (Netherlands)

    Waldorf, BS

    2004-01-01

    This article presents a collection of regional science books that long-standing members of the Regional Science Association International (RSAI) identified as path-breaking books. The most frequently nominated books include the "classics" by Isard, the seminal books in urban economics by Alonso, Mut

  8. Variations on supersymmetry breaking and neutrino spectra

    Energy Technology Data Exchange (ETDEWEB)

    Borzumati, F.; Hamaguchi, K.; Nomura, Y.; Yanagida, T.

    2000-12-11

    The problem of generating light neutrinos within supersymmetric models is discussed. It is shown that the hierarchy of scales induced by supersymmetry breaking can give rise to suppression factors of the correct order of magnitude to produce experimentally allowed neutrino spectra.

  9. Geometrical hierarchy and spontaneous symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Farakos, K.; Koutsoumbas, G.; Surridge, M.; Zoupanos, G.

    1987-06-04

    A four-dimensional gauge theory, where Higgs fields and the corresponding potential appear naturally, is obtained by dimensionally reducing a pure gauge theory over a compact coset space S/R. We show, using an explicit example, that a hierarchy of the scales in the coset space can change the spontaneous symmetry breaking of the four-dimensional gauge theory.

  10. Dimensional reduction and dynamical symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Forgacs, P.; Zoupanos, G.

    1984-11-22

    We present a model in which the electroweak gauge group is broken according to a dynamical scenario based on the chiral symmetry breaking of high colour representations. The dynamical scenario requires also the existence of elementary Higgs fields, which in the present scheme come from the dimensional reduction of a pure gauge theory.

  11. Dimensional reduction and dynamical symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Forgacs, P.; Zoupanos, G. (European Organization for Nuclear Research, Geneva (Switzerland))

    1984-11-22

    We present a model in which the electroweak gauge group is broken according to a dynamical scenario based on the chiral symmetry breaking of high colour representations. The dynamical scenario also requires the existence of elementary Higgs fields, which in the present scheme come from the dimensional reduction of a pure gauge theory.

  12. Dynamical Symmetry Breaking in RN Quantum Gravity

    Directory of Open Access Journals (Sweden)

    A. T. Kotvytskiy

    2011-01-01

    Full Text Available We show that in the RN gravitation model, there is no dynamical symmetry breaking effect in the formalism of the Schwinger-Dyson equation (in flat background space-time. A general formula for the second variation of the gravitational action is obtained from the quantum corrections hμν (in arbitrary background metrics.

  13. Symmetry Breaking for Black-Scholes Equations

    Institute of Scientific and Technical Information of China (English)

    YANG Xuan-Liu; ZHANG Shun-Li; QU Chang-Zheng

    2007-01-01

    Black-Scholes equation is used to model stock option pricing. In this paper, optimal systems with one to four parameters of Lie point symmetries for Black-Scholes equation and its extension are obtained. Their symmetry breaking interaction associated with the optimal systems is also studied. As a result, symmetry reductions and corresponding solutions for the resulting equations are obtained.

  14. A gravity term from spontaneous symmetry breaking

    CERN Document Server

    Moise, Mihai

    2014-01-01

    In this model, the gravity term in the Lagrangean comes from spontaneous symmetry breaking of an additional scalar quadruplet field $\\Upsilon$. The resulting gravitational field is approximate to one of the models of coframe gravity with parameters $\\rho_1 + 4 \\rho_2 = 0$, $\\rho_3 = 0$. This article includes an exact solution of coframe gravity with model parameters $\\rho_1 \

  15. Symmetry and symmetry breaking in particle physics

    OpenAIRE

    Tsou, ST

    1998-01-01

    Symmetry, in particular gauge symmetry, is a fundamental principle in theoretical physics. It is intimately connected to the geometry of fibre bundles. A refinement to the gauge principle, known as ``spontaneous symmetry breaking'', leads to one of the most successful theories in modern particle physics. In this short talk, I shall try to give a taste of this beautiful and exciting concept.

  16. Density Functional Simulation of a Breaking Nanowire

    DEFF Research Database (Denmark)

    Nakamura, A.; Brandbyge, Mads; Hansen, Lars Bruno;

    1999-01-01

    We study the deformation and breaking of an atomic-sized sodium wire using density functional simulations. The wire deforms through sudden atomic rearrangements and smoother atomic displacements. The conductance of the wire exhibits plateaus at integer values in units of 2e(2)/h corresponding...

  17. Supersymmetry Breaking and the Cosmological Constant

    CERN Document Server

    Banks, T

    2014-01-01

    I review three attempts to explain the small value of the cosmological constant, and their connection to SUSY breaking. They are The String Landscape, Supersymmetric Large Extra Dimensions (SLED), and the Holographic Space-time Formalism invented by Fischler and myself.

  18. Transverse bending waves and the breaking broomstick demonstration

    Science.gov (United States)

    Vandegrift, Guy

    1997-06-01

    When a broomstick is supported at both ends by two wine glasses, a strong downward blow to the center will break the stick, leaving the wine glasses undisturbed, provided care is taken to cushion the wine glasses against an initial and brief downward motion of the ends of the broomstick. This downward motion is analyzed and estimated to be about 1 mm in magnitude. Qualitative experimental evidence of this motion is easily obtained using a force probe to monitor a light and nondestructive tap to a 2-m measuring stick. The method of analysis developed here leads to a simple derivation of the dispersion relation for transverse bending waves on a long rod.

  19. Around the cusp singularity and the breaking of waves

    CERN Document Server

    Tejerina-Risso, J

    2012-01-01

    We record the breaking of water waves focusing at the Huygens Cusp of a parabolic wave maker using a fast video camera at a rate of 2000 images per second. The movie shows the very early time of the water tongue plunging ahead of the wave crest. Soon after, some capillarity wavelets are clearly visible. The image analysis of these space time data permits the measurement of the expected 3/2 power of time law as dictated by the cusp singular geometry given by the Catastrophe Theory. To our knowledge this is the first time that this scaling law is measured from fluid dynamics videos.

  20. 双断点塑壳断路器触头固有分断时间等计算分析与优化设计%Analysis and Optimization of Inherent Breaking Time for Two-Breakers Molded Case Circuit Breakers Contacts

    Institute of Scientific and Technical Information of China (English)

    周光照

    2016-01-01

    通过对双断点塑壳断路器触头机构的动作过程的受力与运动的详尽分析,应用SolidWorks软件创建了符合实际情况的物理模型与动力学模型,然后应用MATLAB软件,以双断点断路器触头机构相关参数如杠杆弹簧刚度、下连杆长度、动触头质量等多种参数的变化为实例进行优化设计,计算出对应的触头分断速度、固有分断时间、超行程等断路器关键技术数据,同时得到相应情况下的触点P的运动曲线图,为双断点断路器触头机构的优化设计或逆向工程提供依据和参考。%Through a detailed analysis of the force and motion of action about contact mechanism of the two-breakers molded case circuit breaker, creating a kinetic model in line with the actual situation using SolidWorks software, and then using MATLAB software, two-breakers circuit breaker contacts with institutions spring stiffness related parameters such as leverage, changes in the length of the lower link, the movable contact quality and other parameters to optimize the design for instance, calculate the corresponding contact breaking speed, inherent breaking time, travel and other ultra-breaker key technical data, at the same time the corresponding case of contact P of motion graph provide references for optimizing the design or reverse engineering double-break circuit breaker contacts institutions.

  1. Dynamics of Symmetry Breaking and Tachyonic Preheating

    CERN Document Server

    Felder, G; Greene, P B; Kofman, L A; Linde, Andrei D; Tkachev, Igor I; Felder, Gary; Garcia-Bellido, Juan; Greene, Patrick B.; Kofman, Lev; Linde, Andrei; Tkachev, Igor

    2001-01-01

    We reconsider the old problem of the dynamics of spontaneous symmetry breaking using 3d lattice simulations, and develop a theory of tachyonic preheating, which occurs due to the spinodal instability of the scalar field. Tachyonic preheating is so efficient that symmetry breaking typically completes within a single oscillation of the field distribution as it rolls towards the minimum of its effective potential. As an application of this theory we consider preheating in the hybrid inflation scenario, including SUSY-motivated F-term and D-term inflationary models. We show that preheating in hybrid inflation is typically tachyonic and the stage of oscillations of a homogeneous component of the scalar fields driving inflation ends after a single oscillation. Our results may also be relevant for the theory of the formation of disoriented chiral condensates in heavy ion collisions.

  2. Cosmology of biased discrete symmetry breaking

    Science.gov (United States)

    Gelmini, Graciela B.; Gleiser, Marcelo; Kolb, Edward W.

    1988-01-01

    The cosmological consequences of spontaneous breaking of an approximate discrete symmetry are studied. The breaking leads to formation of proto-domains of false and true vacuum separated by domain walls of thickness determined by the mass scale of the model. The cosmological evolution of the walls is extremely sensitive to the magnitude of the biasing; several scenarios are possible, depending on the interplay between the surface tension on the walls and the volume pressure from the biasing. Walls may disappear almost immediately after they form, or may live long enough to dominate the energy density of the Universe and cause power-law inflation. Limits are obtained on the biasing that characterizes each possible scenario.

  3. Symmetry breaking in non conservative systems

    CERN Document Server

    Martínez-Pérez, N E

    2016-01-01

    We apply Noether's theorem to show how the invariances of conservative systems are broken for nonconservative systems, in the variational formulation of Galley. This formulation considers a conservative action, extended by the inclusion of a time reversed sector and a nonconservative generalized potential. We assume that this potential is invariant under the symmetries of the initial conservative system. The breaking occurs because the time reversed sector requires inverse symmetry transformations, under which the nonconservative potential is not invariant. The resulting violation of the conservation laws is consistent with the equations of motion. We generalize this formulation for fermionic and sypersymmetric systems. In the case of a supersymmetric oscillator, the effect of damping is that the bosonic and fermionic components become different frequencies. Considering that initially the nonconservative action is invariant under supersymmetry, and that the breaking is associated to an instability, this resul...

  4. Metastable spontaneous breaking of N=2 supersymmetry

    Energy Technology Data Exchange (ETDEWEB)

    Légeret, Benoît; Scrucca, Claudio A., E-mail: claudio.scrucca@epfl.ch; Smyth, Paul

    2013-05-24

    We show that contrary to the common lore it is possible to spontaneously break N=2 supersymmetry even in simple theories without constant Fayet–Iliopoulos terms. We consider the most general N=2 supersymmetric theory with one hypermultiplet and one vector multiplet without Fayet–Iliopoulos terms, and show that metastable supersymmetry breaking vacua can arise if both the hyper-Kähler and the special-Kähler geometries are suitably curved. We then also prove that while all the scalars can be massive, the lightest one is always lighter than the vector boson. Finally, we argue that these results also directly imply that metastable de Sitter vacua can exist in N=2 supergravity theories with Abelian gaugings and no Fayet–Iliopoulos terms, again contrary to common lore, at least if the cosmological constant is sufficiently large.

  5. Lyman Break Galaxies in the NGST Era

    CERN Document Server

    Ferguson, H C; Papovich, C; Ferguson, Henry C.; Dickinson, Mark; Papovich, Casey

    2002-01-01

    With SIRTF and NGST in the offing, it is interesting to examine what the stellar populations of z~3 galaxies models imply for the existence and nature of Lyman-break galaxies at higher redshift. To this end, we ``turn back the clock'' on the stellar population models that have been fit to optical and infrared data of Lyman-break galaxies at z~3. The generally young ages (typically 10^8 +- 0.5 yr) of these galaxies imply that their stars were not present much beyond z=4. For smooth star-formation histories SFR(t) and Salpeter IMFs, the ionizing radiation from early star-formation in these galaxies would be insufficient to reionize the intergalactic medium at z~6, and the luminosity density at z~4 would be significantly lower than observed. We examine possible ways to increase the global star-formation rate at higher redshift without violating the stellar-population constraints at z~3.

  6. The Radiative Z2 Breaking Twin Higgs

    CERN Document Server

    Yu, Jiang-Hao

    2016-01-01

    In twin Higgs model, the Higgs boson mass is protected by a $Z_2$ symmetry. The $Z_2$ symmetry needs to be broken either explicitly or spontaneously to obtain misalignment between electroweak and new physics vacua. We propose a novel $Z_2$ breaking mechanism, in which the $Z_2$ is spontaneously broken by radiative corrections to the Higgs potential. Two twin Higgses with different vacua are needed, and vacuum misalignment is realized by opposite but comparable contributions from gauge and Yukawa interactions to the potential. Due to fully radiative symmetry breaking, the Higgs sector is completely determined by twin Higgs vacuum, Yukawa and gauge couplings. There are eight pseudo-Goldstone bosons: the Higgs boson, inert doublet Higgs, and three twin scalars. We show the 125 GeV Higgs mass and constraints from Higgs coupling measurements could be satisfied.

  7. Symmetry Breaking in Neuroevolution: A Technical Report

    CERN Document Server

    Urfalioglu, Onay

    2011-01-01

    Artificial Neural Networks (ANN) comprise important symmetry properties, which can influence the performance of Monte Carlo methods in Neuroevolution. The problem of the symmetries is also known as the competing conventions problem or simply as the permutation problem. In the literature, symmetries are mainly addressed in Genetic Algoritm based approaches. However, investigations in this direction based on other Evolutionary Algorithms (EA) are rare or missing. Furthermore, there are different and contradictionary reports on the efficacy of symmetry breaking. By using a novel viewpoint, we offer a possible explanation for this issue. As a result, we show that a strategy which is invariant to the global optimum can only be successfull on certain problems, whereas it must fail to improve the global convergence on others. We introduce the \\emph{Minimum Global Optimum Proximity} principle as a generalized and adaptive strategy to symmetry breaking, which depends on the location of the global optimum. We apply the...

  8. Collective neutrino oscillations and spontaneous symmetry breaking

    Science.gov (United States)

    Duan, Huaiyu

    2015-08-01

    Neutrino oscillations in a hot and dense astrophysical environment such as a core-collapse supernova pose a challenging, seven-dimensional flavor transport problem. To make the problem even more difficult (and interesting), neutrinos can experience collective oscillations through nonlinear refraction in the dense neutrino medium in this environment. Significant progress has been made in the last decade towards the understanding of collective neutrino oscillations in various simplified neutrino gas models with imposed symmetries and reduced dimensions. However, a series of recent studies seem to have "reset" this progress by showing that these models may not be compatible with collective neutrino oscillations because the latter can break the symmetries spontaneously if they are not imposed. We review some of the key concepts of collective neutrino oscillations by using a few simple toy models. We also elucidate the breaking of spatial and directional symmetries in these models because of collective oscillations.

  9. Collective neutrino oscillations and spontaneous symmetry breaking

    CERN Document Server

    Duan, Huaiyu

    2015-01-01

    Neutrino oscillations in a hot and dense astrophysical environment such as a core-collapse supernova pose a challenging, seven-dimensional flavor transport problem. To make the problem even more difficult (and interesting), neutrinos can experience collective oscillations through nonlinear refraction in the dense neutrino medium in this environment. Significant progress has been made in the last decade towards the understanding of collective neutrino oscillations in various simplified neutrino gas models with imposed symmetries and reduced dimensions. However, a series of recent studies seem to have "reset" this progress by showing that these models may not be compatible with collective neutrino oscillations because the latter can break the symmetries spontaneously if they are not imposed. We review some of the key concepts of collective neutrino oscillations by using a few simple toy models. We also elucidate the breaking of spatial and directional symmetries in these models because of collective oscillation...

  10. Dynamical symmetry breaking in quantum field theories

    CERN Document Server

    Miransky, Vladimir A

    1993-01-01

    The phenomenon of dynamical symmetry breaking (DSB) in quantum field theory is discussed in a detailed and comprehensive way. The deep connection between this phenomenon in condensed matter physics and particle physics is emphasized. The realizations of DSB in such realistic theories as quantum chromodynamics and electroweak theory are considered. Issues intimately connected with DSB such as critical phenomenona and effective lagrangian approach are also discussed.

  11. Music and Video Gaming during Breaks

    OpenAIRE

    Liu, Shuyan; Schad, Daniel J; Kuschpel, Maxim S.; Rapp, Michael A.; Heinz, Andreas

    2016-01-01

    Different systems for habitual versus goal-directed control are thought to underlie human decision-making. Working memory is known to shape these decision-making systems and their interplay, and is known to support goal-directed decision making even under stress. Here, we investigated if and how decision systems are differentially influenced by breaks filled with diverse everyday life activities known to modulate working memory performance. We used a within-subject design where young adult...

  12. Supersymmetry breaking made easy, viable, and generic

    CERN Document Server

    Murayama, Hitoshi

    2007-01-01

    The kind of supersymmetry that can be discovered at the LHC must be very much flavor-blind, which used to require very special intelligently designed models of supersymmetry breaking. This led to the pessimism for some in the community that it is not likely for the LHC to discover supersymmetry. I point out that this is not so, because a garden-variety supersymmetric theories actually can do this job.

  13. Wave breaking in tapered holey fibers

    Institute of Scientific and Technical Information of China (English)

    Shuguang Li; Lei Zhang; Bo Fu; Yi Zheng; Ying Han; Xingtao Zhao

    2011-01-01

    We numerically study the propagation of 1-ps laser pulse in three tapered holey fibers (THFs). The curvature indices of the concave, linear, and convex tapers are 2.0, 1.0, and 0.5, respectively. The central wavelength, located in the normal dispersion regime, is 800 nm. The nonlinear coefficient of the THFs increases from the initial 0.095 m-1· W-1 to the final 0.349 m-l·W-1. Wave breaking accompanied by oscillatory structures occurs near pulse edges, and sidelobes appear in the pulse spectrum. With the increase in propagation distance z, the pulse shape becomes broader and the pulse spectrum flattens. A concave THF is advantageous to the generation of wave breaking and enables easier achievement of super fiat spectra at short lengths.%@@ We numerically study the propagation of 1-ps laser pulse in three tapered holey fibers (THFs).The curvature indices of the concave, linear, and convex tapers are 2.0, 1.0, and 0.5, respectively.The central wavelength, located in the normal dispersion regime, is 800 nm.The nonlinear coefficient of the THFs increases from the initial 0.095 m-1.W-1 to the final 0.349 m-1.W-1.Wave breaking accompanied by oscillatory structures occurs near pulse edges, and sidelobes appear in the pulse spectrum.With the increase in propagation distance z, the pulse shape becomes broader and the pulse spectrum flattens.A concave THF is advantageous to the generation of wave breaking and enables easier achievement of super flat spectra at short lengths.

  14. Adjoint string breaking in the pseudoparticle approach

    CERN Document Server

    Szasz, Christian

    2008-01-01

    We apply the pseudoparticle approach to SU(2) Yang-Mills theory and perform a detailed study of the potential between two static charges for various representations. Whereas for charges in the fundamental representation we find a linearly rising confining potential, we clearly observe string breaking, when considering charges in the adjoint representation. We also demonstrate Casimir scaling and compute gluelump masses for different spin and parity. Numerical results are in qualitative agreement with lattice results.

  15. Spontaneous chiral symmetry breaking in the Tayler instability

    CERN Document Server

    Del Sordo, Fabio; Brandenburg, Axel; Mitra, Dhrubaditya

    2011-01-01

    The chiral symmetry breaking properties of the Tayler instability are discussed. Effective amplitude equations are determined in one case. This model has three free parameters that are determined numerically. Comparison with chiral symmetry breaking in biochemistry is made.

  16. A break in the obesity epidemic?

    DEFF Research Database (Denmark)

    Visscher, T L S; Heitmann, B L; Rissanen, A

    2015-01-01

    Recent epidemiologic papers are presenting prevalence data suggesting breaks and decreases in obesity rates. However, before concluding that the obesity epidemic is not increasing anymore, the validity of the presented data should be discussed more thoroughly. We had a closer look into the litera......, focusing on trends in waist circumference rather than BMI leads to a less optimistic conclusion: the public health problem of obesity is still increasing.International Journal of Obesity advance online publication, 22 July 2014; doi:10.1038/ijo.2014.98.......Recent epidemiologic papers are presenting prevalence data suggesting breaks and decreases in obesity rates. However, before concluding that the obesity epidemic is not increasing anymore, the validity of the presented data should be discussed more thoroughly. We had a closer look...... into the literature presented in recent reviews to address the major potential biases and distortions, and to develop insights about how to interpret the presented suggestions for a potential break in the obesity epidemic. Decreasing participation rates, the use of reported rather than measured data and small sample...

  17. Enhanced breaking of heavy quark spin symmetry

    Directory of Open Access Journals (Sweden)

    Feng-Kun Guo

    2014-11-01

    Full Text Available Heavy quark spin symmetry is useful to make predictions on ratios of decay or production rates of systems involving heavy quarks. The breaking of spin symmetry is generally of the order of O(ΛQCD/mQ, with ΛQCD the scale of QCD and mQ the heavy quark mass. In this paper, we will show that a small S- and D-wave mixing in the wave function of the heavy quarkonium could induce a large breaking in the ratios of partial decay widths. As an example, we consider the decays of the ϒ(10860 into the χbJω (J=0,1,2, which were recently measured by the Belle Collaboration. These decays exhibit a huge breaking of the spin symmetry relation were the ϒ(10860 a pure 5S bottomonium state. We propose that this could be a consequence of a mixing of the S-wave and D-wave components in the ϒ(10860. Prediction on the ratio Γ(ϒ(10860→χb0ω/Γ(ϒ(10860→χb2ω is presented assuming that the decay of the D-wave component is dominated by the coupled-channel effects.

  18. Kinematic dynamo, supersymmetry breaking, and chaos

    Science.gov (United States)

    Ovchinnikov, Igor V.; Enßlin, Torsten A.

    2016-04-01

    The kinematic dynamo (KD) describes the growth of magnetic fields generated by the flow of a conducting medium in the limit of vanishing backaction of the fields onto the flow. The KD is therefore an important model system for understanding astrophysical magnetism. Here, the mathematical correspondence between the KD and a specific stochastic differential equation (SDE) viewed from the perspective of the supersymmetric theory of stochastics (STS) is discussed. The STS is a novel, approximation-free framework to investigate SDEs. The correspondence reported here permits insights from the STS to be applied to the theory of KD and vice versa. It was previously known that the fast KD in the idealistic limit of no magnetic diffusion requires chaotic flows. The KD-STS correspondence shows that this is also true for the diffusive KD. From the STS perspective, the KD possesses a topological supersymmetry, and the dynamo effect can be viewed as its spontaneous breakdown. This supersymmetry breaking can be regarded as the stochastic generalization of the concept of dynamical chaos. As this supersymmetry breaking happens in both the diffusive and the nondiffusive cases, the necessity of the underlying SDE being chaotic is given in either case. The observed exponentially growing and oscillating KD modes prove physically that dynamical spectra of the STS evolution operator that break the topological supersymmetry exist with both real and complex ground state eigenvalues. Finally, we comment on the nonexistence of dynamos for scalar quantities.

  19. Dormancy Breaking in Ormosia arborea Seeds

    Directory of Open Access Journals (Sweden)

    Edilma Pereira Gonçalves

    2011-01-01

    Full Text Available Ormosia arborea is a tree species planted in urban areas and used to restore degraded areas. Its seeds are dormant and propagation is difficult. This study compares different dormancy breaking methods and physiological seed quality and seedling production. The seeds were germinated in sand in the laboratory of the Universidade Estadual de Santa Cruz, Ilhéus, Bahia, Brazil. The following dormancy breaking treatments were applied: control (intact seeds, 100°C water immersion; boiling water immersion followed by 24 hours of soaking; scarification with number 100 and number 50 sandpaper opposite from root emergence; sulfuric acid immersion for 1 hour, 50, 45, and 30 minutes. Seed immersion in 100°C and boiling water did not break the dormancy. The study species showed a greater vigor of seedling when its seeds were submitted to treatments associated with tegument rupturing by sandpaper or sulfuric acid. On the other hand, seed scarification with sulfuric acid for 1 hour, 50, 45, and 30 minutes or sandpaper favored seed germination and vigor.

  20. Breaking bad news: a patient's perspective.

    Science.gov (United States)

    Dias, Lauren; Chabner, Bruce A; Lynch, Thomas J; Penson, Richard T

    2003-01-01

    Shortly before his death in 1995, Kenneth B. Schwartz, a cancer patient at Massachusetts General Hospital (MGH), founded The Kenneth B. Schwartz Center at MGH. The Schwartz Center is a nonprofit organization dedicated to supporting and advancing compassionate health care delivery that provides hope to the patient, support to caregivers, and encourages the healing process. The Center sponsors the Schwartz Center Rounds, a monthly multidisciplinary forum where caregivers reflect on important psychosocial issues faced by patients, their families, and their caregivers, and gain insight and support from fellow staff members. Clinicians in the field of oncology are unavoidably forced to break bad news. The Schwartz Center Rounds focuses on issues of communication between patients and their caregivers, one of the most difficult aspects of which is breaking bad news. The invited patient, a woman who had been living with a low-grade cancer for many years, spoke about her experiences both as a person living with cancer and as the daughter of a patient diagnosed with cancer. Her father's suicide, precipitated by being told his diagnosis, puts the horror of receiving bad news into stark relief. She provides a fascinating account of how she proactively adjusted to her diagnosis, and fought for optimal quality of life. This article discusses issues of support, abandonment, and how hope is conveyed, and reviews the literature that informs good clinical practice in breaking bad news.

  1. Finite Element Analysis of Anti-breaking Performance of Fe-Based SMA Lockut%铁基 SMA 防松螺母防断机理的有限元分析

    Institute of Scientific and Technical Information of China (English)

    李俊良; 沈英明; 杜彦良

    2015-01-01

    采用有限元分析软件 ANSYS 对铁基 SMA 防松螺母的防断机理进行了研究,建立了参数化的螺栓连接有限元计算模型,并与普通螺栓连接进行了对比分析。研究结果表明:这种新型螺母具有很好的变形协调性,并有效地降低螺纹联接受力较大的第一、二螺纹牙处的应力水平。%The anti-breaking mechanism of Fe-based SMA locknut is analyzed and studied by the finite ele-ment software-ANSYS,the parameterized finite element calculation model of the load distribution in the newly-de-signed bolt connection is established based on the comparison with the ordinary bolt connection.The results show that the new type of nut has the better deformation compatibility, and the stresses of the first and second screw thread in the bolt connection are effectively reduced.

  2. The Analysis and Countermeasures for Breaking the Bottleneck of Small and Medium-sized Enterprises’ Funds%破解中小企业资金瓶颈的分析及对策

    Institute of Scientific and Technical Information of China (English)

    杜轶龙

    2011-01-01

    This paper introduces the dilemma of the medium and small enterprises in China in the existing financing mode, and thinks that from China's economic transformation and upgrading of the long-term development, the realistic meaning and urgency of breaking small and medium-sized enterprise capital bottleneck must be considered, and expounds that the financial institutions play the role of investment intermediary and actively promote the innovation of financial market instruments.%文章介绍了我国中小企业在现有融资方式下面临的困境,并从中国经济长远发展和升级转型的角度思考破解中小企业资金瓶颈的现实意义和紧迫性,阐述了发挥金融机构投资中介的作用,积极推进金融市场工具的创新试点的建议措施.

  3. Downslope flow across the Ross Sea shelf break (Antarctica)

    Science.gov (United States)

    Bergamasco, A.; Budillon, G.; Carniel, S.; Defendi, V.; Meloni, R.; Paschini, E.; Sclavo, M.; Spezie, G.

    2003-12-01

    The analysis of some high-resolution hydrological data sets acquired during the 1997, 1998, 2001 and 2003 austral summers across the Ross Sea continental shelf break are here presented. The main focus of these cruises carried out in the framework of the Italian National Antarctic Program was the investigation of the downslope flow of the dense waters originated inside the Ross Sea. Such dense waters, flow near the bottom and, reaching the continental shelf break, ventilate the deep ocean. Two Antarctic continental shelf mechanisms can originate dense and deep waters. The former mechanism involves the formation, along the Victoria Land coasts, of a dense and saline water mass, the High Salinity Shelf Water (HSSW). The HSSW formation is linked to the rejection of salt into the water column as sea ice freezes, especially during winter, in the polynya areas, where the ice is continuously pushed offshore by the strong katabatic winds. The latter one is responsible of the formation of a supercold water mass, the Ice Shelf Water (ISW). The salt supplied by the HSSW recirculated below the Ross Ice Shelf, the latent heat of melting and the heat sink provided by the Ross Ice Shelf give rise to plumes of ISW, characterized by temperatures below the sea-surface freezing point. The dense shelf waters migrate to the continental shelf-break, spill over the shelf edge and descend the continental slope as a shelf-break gravity current, subject to friction and possibly enhanced by topographic channelling. Friction, in particular, breaks the constraint of potential vorticity conservation, counteracting the geostrophic tendency for along slope flow. The density-driven downslope motion or cascading entrains ambient water, namely the lower layer of the CDW, reaches a depth where density is the same and spreads off-slope. In fact, the cascading event is inhibited by friction without entrainment. The downslope processes are important for the ocean and climate system because they play a

  4. Healthy breaks: tasty tips for the under fives

    OpenAIRE

    Public Health Agency

    2014-01-01

    Today the Public Health Agency is launching a new resource pack designed to assist nursery schools and playgroups deliver a healthy breaks scheme.All nursery schools and playgroups in Northern Ireland will receive the pack - 'Healthy breaks for pre-school children' - which includes a poster and information leaflets for parents explaining why a healthy break is so important for pre-school children and some tips and ideas for healthy nutritious breaks.Judith Hanvey, Regional Food in Schools Co-...

  5. Development of trip coverage analysis methodology - CATHENA trip coverage analysis model

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jong Ho; Ohn, M. Y.; Cho, C. H.; Huh, J. Y.; Na, Y. H.; Lee, S. Y.; Kim, B. G.; Kim, H. H.; Kim, S. W.; Bae, C. J.; Kim, T. M.; Kim, S. R.; Han, B. S.; Moon, B. J.; Oh, M. T. [Korea Power Engineering Co., Yongin (Korea)

    2001-05-01

    This report describes the CATHENA model for trip coverage analysis. This model is prepared based on the Wolsong 2 design data and consist of primary heat transport system, shutdown system, steam and feedwater system, reactor regulating system, heat transport pressure and inventory control system, and steam generator level and pressure control system. The new features and modified parts from the Wolsong 2 CATHENA LOCA Model required for trip coverage analysis is described. this model is tested by simulation of steady state at 100 % FP and at several low powers. Also, the cases of power rundown and power runup are tested. 17 refs., 124 figs., 19 tabs. (Author)

  6. External stability for Spherically Symmetric Solutions in Lorentz Breaking Massive Gravity

    CERN Document Server

    Addazi, Andrea

    2014-01-01

    We discuss spherically symmetric solutions for Stars and Black Holes in a class of Lorentz-breaking massive gravity theories. This analysis is valid both for St\\"uckelberg's effective field theory formulation and for Lorentz Breaking Massive Bigravity. The approach consists in analyzing the stability of the geodesic equations out to the star radius, at the first order (deviation equation). The main result is a strong constrain in the the space of parameters of the theory. This strongly motivates an higher order geodetic analysis of perturbations, to understand if it exists a class of spherically symmetric Lorentz-breaking massive gravity solutions for stars, black holes, and, in general, self-gravitating systems stable and phenomenologically acceptable.

  7. Neural networks for the analysis of margins of safety through code BE+U; Redes neuronales para el analisis de margenes de seguridad mediante codigos be+u

    Energy Technology Data Exchange (ETDEWEB)

    Villamizar, M.; Martorell, S.; Villanueva, J. F.; Carlos, S.; Sanchez, A.; Serradell, V.; Mendizabal, R.; Pelayo, F.; Sol, I.

    2011-07-01

    This paper presents the use of tools {sup S}oft Computing{sup ,} in particular the use of artificial neural networks and the method of decomposition of variance as sensitivity analysis, which allows understanding and modeling the relations between variables uncertain input inputs (defined by functions of distribution of Thermo-hydraulic model parameters) and output outputs variable presentation takes place on LOCA accident in a PWR as application.

  8. Jump dynamics with structural breaks for crude oil prices

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yen-Hsien [Department of Finance, Chung Yuan Christian University (China); Hu, Hsu-Ning [Department of Money, Banking and Finance, TamKang University (China); Chiou, Jer-Shiou [Department of Finance and Banking, Shih Chien University, 70 Ta-Chih Street, Taipei 104 (China)

    2010-03-15

    This study investigates the joint phenomena of permanent and transitory components in conditional variance and jump intensity along with verification of structural breaks for crude oil prices. We adopt a Component-ARJI model with structural break analysis, utilizing daily data on West Texas Intermediate crude oil spot and futures contracts. The analytical results verify the existence of permanent and transitory components in conditional variance, with the permanent component of conditional variance increasing with the occurrence of a sudden major event (such as the Iraqi Invasion of Kuwait, Operation Desert Storm and the war between the US and Iraq), and a relatively greater increase in the transitory component over the same period. Notably, jump intensity fluctuates with an increase in the transitory component of conditional variance in response to abnormal events. It is the transitory component which serves as the primary influential factor for jumps in returns; therefore, speculators are willing to take large risks, particularly with respect to anticipating future price movements, or gambling, in the hopes of rapidly making substantial gains; thus, speculators prefer the temporary volatility component and engage in trade activities. However, investors prefer the permanent volatility component, because they may well be better off relocating their assets into more stable portfolios to outperform the market portfolio over the long run. (author)

  9. Low-ℓ CMB from string-scale SUSY breaking?

    Science.gov (United States)

    Sagnotti, A.

    2017-01-01

    Models of inflation are instructive playgrounds for supersymmetry (SUSY) breaking in Supergravity and String Theory. In particular, combinations of branes and orientifolds that are not mutually BPS can lead to brane SUSY breaking, a phenomenon where nonlinear realizations are accompanied, in tachyon-free vacua, by the emergence of steep exponential potentials. When combined with milder terms, these exponentials can lead to slow-roll after a fast ascent and a turning point. This leaves behind distinctive patterns of scalar perturbations, where pre-inflationary peaks can lie well apart from an almost scale invariant profile. I review recent attempts to connect these power spectra to the low-ℓ cosmic microwave background (CMB), and a corresponding one-parameter extension of Lambda cold dark matter (ΛCDM) with a low-frequency cut Δ. A detailed likelihood analysis led to Δ = (0.351 ± 0.114) × 10-3Mpc-1, at 99.4% confidence level, in an extended Galactic mask with fsky = 39%, to be compared with a nearby value at 88.5% in the standard Planck 2015 mask with fsky = 94%. In these scenarios, one would be confronted, in the CMB, with relics of an epoch of deceleration that preceded the onset of slow-roll.

  10. CP breaking in $S(3)$ flavoured Higgs model

    CERN Document Server

    Barradas-Guevara, E; Rodríguez-Jáuregui, E

    2015-01-01

    We analyze the Higgs sector of the minimal $S(3)$-invariant extension of the Standard Model including CP violation arising from the spontaneous breaking of the electroweak symmetry. This extended Higgs sector includes three $SU(2)$ doublets Higgs fields with complex vev's provide an interesting scenario to analyze the Higgs masses spectrum, trilinear self-couplings and CP violation. We present how the spontaneous electroweak symmetry breaking coming from three $S(3)$ Higgs fields gives an interesting scenario with nine physical Higgs and three Goldstone bosons when spontaneous CP violation arises from the Higgs field $S(3)$ singlet $H_S$. Furthermore, numerical analysis of the Higgs masses and trilinear self-couplings is presented, particularly we find a physical solution for the scenario in which spontaneous CPB is provided by the single field $H_S$. The scalar Higgs $H_4^0$ is identified whose mass is 125 GeV and $\\lambda_{H_{4}^0 H_{4}^0 H_{4}^0} \\sim \\lambda_{h^0 h^0 h^0}^{SM}$ in good agreement with the ...

  11. Investigation of a hydraulic impact: a technology in rock breaking

    CERN Document Server

    Genet, Martin; Tran-Cong, Thanh

    2009-01-01

    The finite element method and dimensional analysis have been applied in the present paper to study a hydraulic impact, which is utilized in a non-explosive rock breaking technology in mining industry. The impact process of a high speed piston on liquid water, previously introduced in a borehole drilled in rock, is numerically simulated. The research is focused on the influences of all the parameters involved in the technology on the largest principal stress in the rock, which is considered as one of the key factors to break the rock. Our detailed parametric investigation reveals that the variation of the isotropic rock material properties, especially its density, has no significant influence on the largest principal stress. The influences of the depth of the hole and the depth of the water column are also very small. On the other hand, increasing the initial kinetic energy of the piston can dramatically increase the largest principal stress and the best way to increase the initial kinetic energy of the piston...

  12. Breaking Tri-Bimaximal Mixing and Large θ13

    Science.gov (United States)

    Shimizu, Y.; Tanimoto, M.; Watanabe, A.

    2011-07-01

    The long baseline neutrino experiment, T2K, and the reactor experiment, Double Chooz will soon present new data. If we expect sinθ_{13} to be 0.1 - 0.2, which is close to the present experimental upper bound, we should not persist in the paradigm of the tri-bimaximal mixing. We discuss breaking the tri-bimaximal mixing by adding a simple mass matrix, which could be derived from some non-Abelian discrete symmetries. It is found that sinθ_{13} = 0.1 - 0.2 is expected in our model independent analysis of the generalized mass matrix for the normal or inverted hierarchical neutrino mass spectrum. On the other hand, sin^2θ_{23} and sin^2θ_{12} are expected to be not far from 1/2 and 1/3, respectively. As a typical example, we also discuss the A_4 flavor model with the 1 and 1' flavons, which break the tri-bimaximal mixing considerably. In this modified version of the Altarelli and Feruglio model, sinθ_{13} is predicted to be around 0.15 in the case of the normal hierarchical neutrino masses m_3 ≫ m_2, m_1, and 0.2 in the case of the inverted hierarchy m_3 ≪ m_2, m_1. The form of the neutrino mass matrix looks rather interesting -- it is suggestive of other discrete symmetries as well.

  13. Breaking Tri-bimaximal Mixing and Large $\\theta_{13}$

    CERN Document Server

    Shimizu, Yusuke; Watanabe, Atsushi

    2011-01-01

    The long baseline neutrino experiment, T2K, and the reactor experiment, Double Chooz will soon present new data. If we expect $\\sin\\theta_{13}$ to be 0.1-0.2, which is close to the present experimental upper bound, we should not persist in the paradigm of the tri-bimaximal mixing. We discuss the breaking the tri-bimaximal mixing by adding a simple mass matrix, which could be derived from some non-Abelian discrete symmetries. It is found that $\\sin\\theta_{13}=0.1-0.2$ is expected in our model independent analysis of the generalized mass matrix. On the other hand, $\\sin^2\\theta_{23}$ and $\\sin^2\\theta_{12}$ are expected to be not far from 1/2 and 1/3, respectively. As a typical example, we also discuss the $A_4$ flavor model with the 1 and 1' flavons, which break the tri-bimaximal mixing considerably. In this modified version of the Altarelli and Feruglio model, $\\sin\\theta_{13}$ is predicted to be around 0.15 in the case of the normal hierarchical neutrino masses $m_3\\gg m_2, m_1$, and 0.2 in the case of the i...

  14. Spontaneous symmetry breaking in a classical particle

    CERN Document Server

    Sánchez, L A; Sanchez, Luis Alberto; Mahecha, Jorge

    2003-01-01

    Due to the fact that only matter fields have phase, frequently is believed that the gauge principle can induce gauge fields only in quantum systems. But this is not necessary. This paper, of pedagogical scope, presents a classical system constituted by a particle in a classical potential, which is used as a model to illustrate the gauge principle and the spontaneous symmetry breaking. Those concepts appear in the study of second order phase transitions. Ferroelectricity, ferromagnetism, superconductivity, plasmons in a free electron gas, and the mass of vector bosons in the gauge field Yang-Mills theories, are some of the phenomena in which these transitions occur.

  15. Phenomenology of symmetry breaking from extra dimensions

    CERN Document Server

    Alfaro, J; Gavela-Legazpi, Maria Belen; Rigolin, S; Salvatori, M

    2007-01-01

    Motivated by the electroweak hierarchy problem, we study the symmetry breaking pattern induced by a background magnetic flux living on extra dimensions, with the four-dimensional scalar fields being gauge boson components in full space. For SU(N) and two compact, toroidal, extra dimensions, we determine analytically the possible field configurations of stable vacua and their symmetries. From the four-dimensional point of view, the system responds dynamically to the magnetic background by an infinite chain of vacuum expectation values so as to reach a stable vacuum. The equivalence between flux compactification and constant boundary conditions - either Scherk-Schwarz or twisted - is established.

  16. Electroweak symmetry breaking beyond the Standard Model

    Indian Academy of Sciences (India)

    Gautam Bhattacharyya

    2012-10-01

    In this paper, two key issues related to electroweak symmetry breaking are addressed. First, how fine-tuned different models are that trigger this phenomenon? Second, even if a light Higgs boson exists, does it have to be necessarily elementary? After a brief introduction, the fine-tuning aspects of the MSSM, NMSSM, generalized NMSSM and GMSB scenarios shall be reviewed, then the little Higgs, composite Higgs and the Higgsless models shall be compared. Finally, a broad overview will be given on where we stand at the end of 2011.

  17. Breaking Barriers in Polymer Additive Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Love, Lonnie J [ORNL; Duty, Chad E [ORNL; Post, Brian K [ORNL; Lind, Randall F [ORNL; Lloyd, Peter D [ORNL; Kunc, Vlastimil [ORNL; Peter, William H [ORNL; Blue, Craig A [ORNL

    2015-01-01

    Additive Manufacturing (AM) enables the creation of complex structures directly from a computer-aided design (CAD). There are limitations that prevent the technology from realizing its full potential. AM has been criticized for being slow and expensive with limited build size. Oak Ridge National Laboratory (ORNL) has developed a large scale AM system that improves upon each of these areas by more than an order of magnitude. The Big Area Additive Manufacturing (BAAM) system directly converts low cost pellets into a large, three-dimensional part at a rate exceeding 25 kg/h. By breaking these traditional barriers, it is possible for polymer AM to penetrate new manufacturing markets.

  18. String Breaking in Four Dimensional Lattice QCD

    CERN Document Server

    Duncan, A; Thacker, H

    2001-01-01

    Virtual quark pair screening leads to breaking of the string between fundamental representation quarks in QCD. For unquenched four dimensional lattice QCD, this (so far elusive) phenomenon is studied using the recently developed truncated determinant algorithm (TDA). The dynamical configurations were generated on an Athlon 650 MHz PC. Quark eigenmodes up to 420 MeV are included exactly in these TDA studies performed at low quark mass on large coarse (but O($a^2$) improved) lattices. A study of Wilson line correlators in Coulomb gauge extracted from an ensemble of 1000 two-flavor dynamical configurations reveals evidence for flattening of the string tension at distances R $\\geq$ approximately 1 fm.

  19. On inflation, cosmological constant, and SUSY breaking

    CERN Document Server

    Linde, Andrei

    2016-01-01

    We consider a broad class of inflationary models of two unconstrained chiral superfields, the stabilizer $S$ and the inflaton $\\Phi$, which can describe inflationary models with nearly arbitrary potentials. These models include, in particular, the recently introduced theories of cosmological attractors, which provide an excellent fit to the latest Planck data. We show that by adding to the superpotential of the fields $S$ and $\\Phi$ a small term depending on a nilpotent chiral superfield $P$ one can break SUSY and introduce a small cosmological constant without affecting main predictions of the original inflationary scenario.

  20. SU(3) flavour breaking and baryon structure

    Energy Technology Data Exchange (ETDEWEB)

    Cooke, A.N.; Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Nakamura, Y. [RIKEN Advanced Institute for Computational Science, Kobe, Hyogo (Japan); Pleiter, D. [Forschungszentrum Juelich GmbH (Germany). Juelich Supercomputing Centre (JSC); Regensburg Univ. (Germany). Institut fuer Theoretische Physik; Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Div.; Shanahan, P.; Zanotti, J.M. [Adelaide Univ., SA (Australia). CSSM, School of Chemistry and Physics; Schierholz, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Stueben, H. [Hamburg Univ. (Germany). Regionales Rechenzentrum; Collaboration: QCDSF/UKQCD Collaboration

    2013-11-15

    We present results from the QCDSF/UKQCD collaboration for hyperon electromagnetic form factors and axial charges obtained from simulations using N{sub f}=2+1 flavours of O(a)-improved Wilson fermions. We also consider matrix elements relevant for hyperon semileptonic decays. We find flavour-breaking effects in hyperon magnetic moments which are consistent with experiment, while our results for the connected quark spin content indicates that quarks contribute more to the spin of the {Xi} baryon than they do to the proton.

  1. De Sitter Uplift with Dynamical Susy Breaking

    CERN Document Server

    Retolaza, Ander

    2015-01-01

    We propose the use of D-brane realizations of Dynamical Supersymmetry Breaking (DSB) gauge sectors as sources of uplift in compactifications with moduli stabilization onto de Sitter vacua. This construction is fairly different from the introduction of anti D-branes, yet allows for tunably small contributions to the vacuum energy via their embedding into warped throats. The idea is explicitly exemplified by the embedding of the 1-family $SU(5)$ DSB model in a local warped throat with fluxes, which we discuss in detail in terms of orientifolds of dimer diagrams.

  2. De Sitter uplift with Dynamical Susy Breaking

    Science.gov (United States)

    Retolaza, Ander; Uranga, Angel

    2016-04-01

    We propose the use of D-brane realizations of Dynamical Supersymmetry Breaking (DSB) gauge sectors as sources of uplift in compactifications with moduli stabilization onto de Sitter vacua. This construction is fairly different from the introduction of anti D-branes, yet allows for tunably small contributions to the vacuum energy via their embedding into warped throats. The idea is explicitly exemplified by the embedding of the 1-family SU(5) DSB model in a local warped throat with fluxes, which we discuss in detail in terms of orientifolds of dimer diagrams.

  3. Breaking of Cooper pairs in 108Pd

    Science.gov (United States)

    Rahmatinejad, A.; Kakavand, T.; Razavi, R.

    2016-04-01

    In this paper, breaking of Cooper pairs in 108Pd is investigated within the canonical ensemble framework and the BCS model. Our results show an evidence of two phase transitions, which are related to neutron and proton systems. Also, with consideration of pairing interaction, the role of neutron and proton systems in entropy, spin cutoff parameter and as a result in the moment of inertia are investigated. The results show minor role for the proton system at low temperatures and approximately equal roles for both neutron and proton systems after the critical temperature. Good agreement was observed between obtained results and the experimental data.

  4. Dynamical Supersymmetry Breaking Why and How

    CERN Document Server

    Poppitz, E R

    1998-01-01

    This theoretical review is intended to give non-theorists a flavor of the ideas driving the current efforts to experimentally find supersymmetry. We discuss the main reasons behind the expectation that supersymmetry may be "just around the corner" and may be discovered in the near future. We use simple quantum-mechanical examples to illustrate the concept---and the power---of supersymmetry, the possible ways to break supersymmetry, and the dynamical generation of small scales. We then describe how this theoretical machinery helps shape our perception of what physics beyond the electroweak scale might be.

  5. Cascading Multicriticality in Nonrelativistic Spontaneous Symmetry Breaking

    CERN Document Server

    Griffin, Tom; Horava, Petr; Yan, Ziqi

    2015-01-01

    Without Lorentz invariance, spontaneous global symmetry breaking can lead to multicritical Nambu-Goldstone modes with a higher-order low-energy dispersion $\\omega\\sim k^n$ ($n=2,3,\\ldots$), whose naturalness is protected by polynomial shift symmetries. Here we investigate the role of infrared divergences and the nonrelativistic generalization of the Coleman-Hohenberg-Mermin-Wagner (CHMW) theorem. We find novel cascading phenomena with large hierarchies between the scales at which the value of $n$ changes, leading to an evasion of the "no-go" consequences of the relativistic CHMW theorem.

  6. Cosmological SUSY Breaking and the Pyramid Schemes

    CERN Document Server

    Banks, T

    2014-01-01

    I review the ideas of holographic space-time (HST), Cosmological SUSY breaking (CSB), and the Pyramid Schemes, which are the only known models of Tera-scale physics consistent with CSB, current particle data, and gauge coupling unification. There is considerable uncertainty in the estimate of the masses of supersymmetric partners of the standard model particles, but the model predicts that the gluino is probably out of reach of the LHC, squarks may be in reach, and the NLSP is a right handed slepton, which should be discovered soon.

  7. Tree Level Mediation of Supersymmetry Breaking

    Energy Technology Data Exchange (ETDEWEB)

    Nardecchia, Marco, E-mail: marco.nardecchia@sissa.it [SISSA/ISAS and INFN, I-34013 Trieste (Italy)

    2010-11-01

    We propose a new scheme in which supersymmetry breaking is communicated to the MSSM sfermions by GUT gauge interactions at the tree level. The (positive) contribution of MSSM fields to Str(M{sup 2}) is automatically compensated by a (negative) contribution from heavy fields. Sfermion masses are flavour universal, thus solving the supersymmetric flavour problem. In the simplest SO(10) embedding, the ratio of different sfermion masses is predicted and differs from mSugra and other schemes, thus making this framework testable at the LHC. Gaugino masses are generated at the loop level but enhanced by model dependent factors.

  8. Insight into Phenomena of Symmetry Breaking Bifurcation

    Institute of Scientific and Technical Information of China (English)

    FANG Tong; ZHANG Ying

    2008-01-01

    @@ We show that symmetry-breaking (SB) bifurcation is just a transition of different forms of symmetry, while still preserving system's symmetry. SB bifurcation always associates with a periodic saddle-node bifurcation, identifiable by a zero maximum of the top Lyapunov exponent of the system. In addition, we show a significant phase portrait of a newly born periodic saddle and its stable and unstable invariant manifolds, together with their neighbouring flow pattern of Poincaré mapping points just after the periodic saddle-node bifurcation, thus gaining an insight into the mechanism of SB bifurcation.

  9. Parity Breaking Medium and Squeeze Operators

    CERN Document Server

    Andrianov, A A; Soldati, R

    2016-01-01

    The transition between a Minkowski space region and a parity breaking medium domain is thoroughly discussed. The requirement of continuity of the field operator content across the separating boundary of the two domains leads to Bogolyubov transformations, squeezed pairs states and squeeze operators that turn out to generate a functional SU(2) algebra. According to this algebraic approach, the reflection and transmission probability amplitude across the separating boundary are computed. The suitable generalization of the well known Sauter-Schwinger-Nikishov formula to the emission or absorption of squeezed pairs out of the vacuum is obtained.

  10. 高校助学贷款违约问题分析及改进思路%Analysis and Improvement Ideas on University Students' Breaking Contracts on Loans to Students as Financial Aid

    Institute of Scientific and Technical Information of China (English)

    董斌彬

    2012-01-01

    至今已超过400万的高校贫困生在国家助学贷款政策支持下完成了学业,但在实际操作过程中出现的违约率居高不下的现象,引起了社会对高校助贷体系及大学生诚信问题的质疑。政府应完善相关法规制度,加强管理,督促银行建立还贷监测系统,大力开展生源地助学贷款。高校应加强政策宣传工作,辅以诚信和感恩教育,帮助家庭困难学生树立自信自强信念。通过政府、银行、高校、学生四个方面的相互协调,共同营造良好的助学环境。%By now there have been more than four million poor students finishing their study in universities, supported by the policy issued by our country, issuing loans for the students as financial aid. However, in practice, there have also been high rate of the students' breaking contracts on the loan, which has caused the society to question the loan system conducted in universities as well as the students' faith. The government should strengthen management by perfecting relative law and regulations. It should promote banks to establish supervising system so as to develop loans as financial aid coming from the students' hometown. Universities should strengthen propaganda on the policy, conducting education on faith and thankfulness, so as to help poor students build the idea of'self-confidence and self-aid. Government, banks, universities, and students should all make efforts to establish a good environment for loans to students as financial aid.

  11. Yabancı Doğrudan Yatırımların İstihdam Üzerindeki Etkisi: Türkiye, Çin ve Hindistan Örneğinde Çoklu Yapısal Kırılmalı Eşbütünleşme Analizi(Foreign Direct Investments’ Effect on the Employment: Cointegration Analysis with Multiple Structural Breaks in Turkey, China and India Sample

    Directory of Open Access Journals (Sweden)

    İsmet GÖÇER

    2014-06-01

    Full Text Available In this study effects of foreign direct investment on employment, analyzed with multiple structural breaks unit root test of Carrion-i-Silvestre et al. (2009, multiple structural breaks cointegration test of Maki (2012 and dynamic ordinary least squares method for Turkey, China and India by using 1980-2011 period data. According to the empirical findings; series are non-stationary in level and there is a cointegration relationship between series. As a result of the long run analysis; 10% increase of foreign direct investment leads to a decreases on the employment in Turkey by 0.3%while decreases in China and India respectively by 0.3% and 0.2%.

  12. Chiral Gauge Dynamics and Dynamical Supersymmetry Breaking

    Energy Technology Data Exchange (ETDEWEB)

    Poppitz, Erich; /Toronto U.; Unsal, Mithat; /SLAC /Stanford U.

    2009-05-07

    We study the dynamics of a chiral SU(2) gauge theory with a Weyl fermion in the I = 3/2 representation and of its supersymmetric generalization. In the former, we find a new and exotic mechanism of confinement, induced by topological excitations that we refer to as magnetic quintets. The supersymmetric version was examined earlier in the context of dynamical supersymmetry breaking by Intriligator, Seiberg, and Shenker, who showed that if this gauge theory confines at the origin of moduli space, one may break supersymmetry by adding a tree level superpotential. We examine the dynamics by deforming the theory on S{sup 1} x R{sup 3}, and show that the infrared behavior of this theory is an interacting CFT at small S{sup 1}. We argue that this continues to hold at large S{sup 1}, and if so, that supersymmetry must remain unbroken. Our methods also provide the microscopic origin of various superpotentials in SQCD on S{sup 1} x R{sup 3}--which were previously obtained by using symmetry and holomorphy--and resolve a long standing interpretational puzzle concerning a flux operator discovered by Affleck, Harvey, and Witten. It is generated by a topological excitation, a 'magnetic bion', whose stability is due to fermion pair exchange between its constituents. We also briefly comment on composite monopole operators as leading effects in two dimensional antiferromagnets.

  13. Large-field inflation and supersymmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Buchmueller, Wilfried; Wieck, Clemens [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Dudas, Emilian; Heurtier, Lucien [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Ecole Polytechnique, Palaiseau (France). CPht

    2014-07-15

    Large-field inflation is an interesting and predictive scenario. Its non-trivial embedding in supergravity was intensively studied in the recent literature, whereas its interplay with supersymmetry breaking has been less thoroughly investigated. We consider the minimal viable model of chaotic inflation in supergravity containing a stabilizer field, and add a Polonyi field. Furthermore, we study two possible extensions of the minimal setup. We show that there are various constraints: first of all, it is very hard to couple an O'Raifeartaigh sector with the inflaton sector, the simplest viable option being to couple them only through gravity. Second, even in the simplest model the gravitino mass is bounded from above parametrically by the inflaton mass. Therefore, high-scale supersymmetry breaking is hard to implement in a chaotic inflation setup. As a separate comment we analyze the simplest chaotic inflation construction without a stabilizer field, together with a supersymmetrically stabilized Kaehler modulus. Without a modulus, the potential of such a model is unbounded from below. We show that a heavy modulus cannot solve this problem.

  14. The Masses of Lyman Break Galaxies

    Science.gov (United States)

    Primack, Joel R.; Wechsler, Risa H.; Somerville, Rachel S.

    Data on galaxies at high redshift, identified by the Lyman-break photometric technique, can teach us about how galaxies form and evolve. The stellar masses and other properties of such Lyman break galaxies (LBGs) depend sensitively on the details of star formation. In this paper we consider three different star formation prescriptions, and use semi-analytic methods applied to the now-standard ΛCDM theory of hierarchical structure formation to show how these assumptions about star formation affect the predicted masses of the stars in these galaxies and the masses of the dark matter halos that host them. We find that, within the rather large uncertainties, recent estimates of the stellar masses of LBGs from multi-color photometry are consistent with the predictions of all three models. However, the estimated stellar masses are more consistent with the predictions of two of the models in which star formation is accelerated at high redshifts z ≳ 3, and of these models the one in which many of the LBGs are merger-driven starbursts is also more consistent with indications that many high redshift galaxies are gas rich. The clustering properties of LBGs have put some constraints on the masses of their host halos, but due to similarities in the halo occupation of the three models we consider and degeneracies between model parameters, current constraints are not yet sufficient to distinguish between realistic models.

  15. The Masses of Lyman Break Galaxies

    CERN Document Server

    Primack, Joel R; Somerville, R S; Primack, Joel R.; Wechsler, Risa H.; Somerville, Rachel S.

    2001-01-01

    Data on galaxies at high redshift, identified by the Lyman-break photometric technique, can teach us about how galaxies form and evolve. The stellar masses and other properties of such Lyman break galaxies (LBGs) depend sensitively on the details of star formation. In this paper we consider three different star formation prescriptions, and use semi-analytic methods applied to the now-standard $\\Lambda$CDM theory of hierarchical structure formation to show how these assumptions about star formation affect the predicted masses of the stars in these galaxies and the masses of the dark matter halos that host them. We find that, within the rather large uncertainties, recent estimates of the stellar masses of LBGs from multi-color photometry are consistent with the predictions of all three models. However, the estimated stellar masses are more consistent with the predictions of two of the models in which star formation is accelerated at high redshifts $z\\gsim3$, and of these models the one in which many of the LBGs...

  16. Chiral symmetry breaking, instantons, and monopoles

    CERN Document Server

    Di Giacomo, Adriano

    2015-01-01

    The purpose of this study is to show that monopoles induce the chiral symmetry breaking. In order to indicate the evidence, we add one pair of monopoles with magnetic charges to the quenched SU(3) configurations by a monopole creation operator, and investigate the propaties of the chiral symmetry breaking using the Overlap fermion. We show that instantons are created by the monopoles. The pseudoscalar meson mass and decay constant are computed from the correlation functions, and the renormalization constant $Z_{S}$ is determined by the non perturbative method. The renormalization group invariant chiral condensate in $\\overline{\\mbox{MS}}$-scheme at 2 [GeV] is evaluated by the Gell-Mann-Oakes-Renner formula, and the random matrix theory. Finally, we estimate the renormalization group invariant quark masses $\\bar{m} = (m_{u} + m_{d})/2$, and $m_{s}$ in $\\overline{\\mbox{MS}}$-scheme at 2 [GeV]. The preliminary results indicate that the chiral condensate decreases and the quark masses become slightly heavy by inc...

  17. Generalized Soft Breaking Leverage for the MSSM

    CERN Document Server

    Ün, Cem Salih; Kerman, Saime; Solmaz, Levent

    2014-01-01

    In this work we study implications of additional non-holomorphic soft breaking terms (mu', A'_t, A'_b and A'_tau$) on the MSSM phenomenology. By respecting the existing bounds on the mass measurements and restrictions coming from certain B-decays, we probe reactions of the MSSM to these additional soft breaking terms. We provide examples in which some slightly excluded solutions of the MSSM can be made to be consistent with the current experimental results. During this, even after applying additional fine-tuning constraints the non-holomorphic terms are allowed to be as large as hundreds of GeV. Such terms prove that they are capable of enriching the phenomenology and varying the mass spectra of the MSSM heavily, with a reasonable amount of fine-tuning. We observe that higgsinos, the lightest stop, the heavy Higgs boson states A, H, charged H, sbottom and stau exhibit the highest sensitivity to the new terms. We also show how the light stop can become nearly degenerate with top quark using these non-holomorph...

  18. Chip breaking system for automated machine tool

    Science.gov (United States)

    Arehart, Theodore A.; Carey, Donald O.

    1987-01-01

    The invention is a rotary selectively directional valve assembly for use in an automated turret lathe for directing a stream of high pressure liquid machining coolant to the interface of a machine tool and workpiece for breaking up ribbon-shaped chips during the formation thereof so as to inhibit scratching or other marring of the machined surfaces by these ribbon-shaped chips. The valve assembly is provided by a manifold arrangement having a plurality of circumferentially spaced apart ports each coupled to a machine tool. The manifold is rotatable with the turret when the turret is positioned for alignment of a machine tool in a machining relationship with the workpiece. The manifold is connected to a non-rotational header having a single passageway therethrough which conveys the high pressure coolant to only the port in the manifold which is in registry with the tool disposed in a working relationship with the workpiece. To position the machine tools the turret is rotated and one of the tools is placed in a material-removing relationship of the workpiece. The passageway in the header and one of the ports in the manifold arrangement are then automatically aligned to supply the machining coolant to the machine tool workpiece interface for breaking up of the chips as well as cooling the tool and workpiece during the machining operation.

  19. Repair of DNA Double-Strand Breaks

    Science.gov (United States)

    Falk, Martin; Lukasova, Emilie; Kozubek, Stanislav

    The genetic information of cells continuously undergoes damage induced by intracellular processes including energy metabolism, DNA replication and transcription, and by environmental factors such as mutagenic chemicals and UV and ionizing radiation. This causes numerous DNA lesions, including double strand breaks (DSBs). Since cells cannot escape this damage or normally function with a damaged genome, several DNA repair mechanisms have evolved. Although most "single-stranded" DNA lesions are rapidly removed from DNA without permanent damage, DSBs completely break the DNA molecule, presenting a real challenge for repair mechanisms, with the highest risk among DNA lesions of incorrect repair. Hence, DSBs can have serious consequences for human health. Therefore, in this chapter, we will refer only to this type of DNA damage. In addition to the biochemical aspects of DSB repair, which have been extensively studied over a long period of time, the spatio-temporal organization of DSB induction and repair, the importance of which was recognized only recently, will be considered in terms of current knowledge and remaining questions.

  20. Spontaneous spherical symmetry breaking in atomic confinement

    CERN Document Server

    Sveshnikov, K

    2016-01-01

    The effect of spontaneous breaking of initial SO(3) symmetry is shown to be possible for an H-like atom in the ground state, when it is confined in a spherical box under general boundary conditions of "not going out" through the box surface (i.e. third kind or Robin's ones), for a wide range of physically reasonable values of system parameters. The reason is that such boundary conditions could yield a large magnitude of electronic wavefunction in some sector of the box boundary, what in turn promotes atomic displacement from the box center towards this part of the boundary, and so the underlying SO(3) symmetry spontaneously breaks. The emerging Goldstone modes, coinciding with rotations around the box center, restore the symmetry by spreading the atom over a spherical shell localized at some distances from the box center. Atomic confinement inside the cavity proceeds dynamically -- due to the boundary condition the deformation of electronic wavefunction near the boundary works as a spring, that returns the at...

  1. Golden Probe of Electroweak Symmetry Breaking

    Science.gov (United States)

    Chen, Yi; Lykken, Joe; Spiropulu, Maria; Stolarski, Daniel; Vega-Morales, Roberto

    2016-12-01

    The ratio of the Higgs couplings to W W and Z Z pairs, λW Z, is a fundamental parameter in electroweak symmetry breaking as well as a measure of the (approximate) custodial symmetry possessed by the gauge boson mass matrix. We show that Higgs decays to four leptons are sensitive, via tree level or one-loop interference effects, to both the magnitude and, in particular, overall sign of λW Z. Determining this sign requires interference effects, as it is nearly impossible to measure with rate information. Furthermore, simply determining the sign effectively establishes the custodial representation of the Higgs boson. We find that h →4 ℓ (4 ℓ≡2 e 2 μ , 4 e , 4 μ ) decays have excellent prospects of directly establishing the overall sign at a high luminosity 13 TeV LHC. We also examine the ultimate LHC sensitivity in h →4 ℓ to the magnitude of λW Z. Our results are independent of other measurements of the Higgs boson couplings and, in particular, largely free of assumptions about the top quark Yukawa couplings which also enter at one loop. This makes h →4 ℓ a unique and independent probe of electroweak symmetry breaking and custodial symmetry.

  2. Retinal breaks due to intravitreal ocriplasmin

    Directory of Open Access Journals (Sweden)

    Silva RA

    2014-08-01

    Full Text Available Ruwan A Silva, Darius M Moshfeghi, Theodore Leng Byers Eye Institute at Stanford, Stanford University School of Medicine, Palo Alto, CA, USA Abstract: Ocriplasmin represents a new treatment option for numerous vitreoretinopathies involving an abnormal vitreomacular interface. While the drug may circumvent the traditional risks of surgical treatment, pharmacologic vitreolysis is not devoid of risk itself. This report presents two cases, one of vitreomacular traction syndrome and the other of a full-thickness macular hole, both of which were treated with an intravitreal injection of ocriplasmin. Notably, in both cases, vitreomacular traction of the macula appears to have been alleviated; however, failure to completely relieve vitreoretinal traction from the peripheral retina generated retinal breaks with one patient eventually developing a macula-involving retinal detachment. Thus, even in instances of ‘successful’ pharmacologic treatment of vitreomacular traction, continued follow-up evaluation is essential. Keywords: posterior vitreous detachment, retinal detachment, vitreomacular traction, ocriplasmin, retinal break, macular hole, laser retinopexy

  3. D-branes, Supersymmetry Breaking, and Neutrinos

    CERN Document Server

    Seo, Jihye

    2010-01-01

    This thesis studies meta- and exactly stable supersymmetry breaking mechanisms in heterotic and type IIB string theories and constructs an F-theory Grand Unified Theory model for neutrino physics in which neutrino mass is determined by the supersymmetry breaking mechanism. Focussing attention on heterotic string theory compactified on a 4-torus, stability of non-supersymmetric states is studied. A non-supersymmetric state with robust stability is constructed, and its exact stability is proven in a large region of moduli space of T^4 against all the possible decay mechanisms allowed by charge conservation. Using string-string duality, the results are interpreted in terms of Dirichlet-branes in type IIA string theory compactified on an orbifold limit of a K3 surface. In type IIB string theory, metastable and exactly stable non-supersymmetric systems are constructed using D-branes and Calabi-Yau geometry. Branes and anti-branes wrap rigid and separate 2-spheres inside a non-compact Calabi-Yau three-fold: supersy...

  4. A Cost-Benefit Study of a Breaking the Cycle Program for Juveniles

    Science.gov (United States)

    Cowell, Alexander J.; Lattimore, Pamela K.; Krebs, Christopher P.

    2010-01-01

    The authors present a cost-benefit analysis of a Juvenile Breaking the Cycle (JBTC) program in Oregon designed to provide juvenile justice system monitoring and coordinated treatment and services to youth who are assessed as at high risk for recidivism and substance use. Detailed cost analyses are presented for youth in the JBTC program and a…

  5. Asymptotic growth of cumulative and regenerative beam break-up instabilities in accelerators

    Science.gov (United States)

    Lau, Y. Y.

    1988-06-01

    It is found that the asymptotic growth of the cumulative beam break up instability is independent of the focusing magnetic field, according to the model of Panofsky and Bander. The analysis is extended to include the transition from the cumulative to the regenerative type, both in the presence and absence of a focusing magnetic field.

  6. Pair-breaking and superconducting state recovery dynamics in MgB2.

    Science.gov (United States)

    Demsar, J; Averitt, R D; Taylor, A J; Kabanov, V V; Kang, W N; Kim, H J; Choi, E M; Lee, S I

    2003-12-31

    We present studies of the photoexcited quasiparticle dynamics in MgB2 where, using femtosecond optical techniques, Cooper pair-breaking dynamics (PBD) have been temporally resolved for the first time. The PBD are strongly temperature and photoexcitation intensity dependent. Analysis of the PBD using the Rothwarf-Taylor equations suggests that the anomalous PBD arises from the fact that in MgB2 photoexcitation is initially followed by energy relaxation to high frequency phonons instead of, as commonly assumed, e-e thermalization. Furthermore, the bare quasiparticle recombination rate and the probability for pair breaking by phonons have been determined.

  7. The experience of breaks in psychotherapy with children who suffered massive early trauma

    DEFF Research Database (Denmark)

    Grünbaum, Liselotte

    with birth and foster parents. Principles were worked out for transparent, theoretically informed sampling of session material and other information. Disconfirming case analysis and a relational mapping chart worked out to allow for time-sequenced exploration. A subsequent study assessed the scope of results...... by a comparable investigation of summer vacation breaks in student-therapist`s supervised, concluded therapies. Findings highlighted 1) links between breaks and the eruption of hostile parental and sibling figures in mind; 2) links between the emotional quality of sibling and parental figures; 3) differences...

  8. The concepts of leak before break and absolute reliability of NPP equipment and piping

    Energy Technology Data Exchange (ETDEWEB)

    Getman, A.F.; Komarov, O.V.; Sokov, L.M. [and others

    1997-04-01

    This paper describes the absolute reliability (AR) concept for ensuring safe operation of nuclear plant equipment and piping. The AR of a pipeline or component is defined as the level of reliability when the probability of an instantaneous double-ended break is near zero. AR analysis has been applied to Russian RBMK and VVER type reactors. It is proposed that analyses required for application of the leak before break concept should be included in AR implementation. The basic principles, methods, and approaches that provide the basis for implementing the AR concept are described.

  9. The Effective Kahler Potential, Metastable Vacua and R-Symmetry Breaking in O'Raifeartaigh Models

    CERN Document Server

    Benjamin, Shermane; Kain, Ben

    2010-01-01

    Much has been learned about metastable vacua and R-symmetry breaking in O'Raifeartaigh models. Such work has largely been done from the perspective of the superpotential and by including Coleman-Weinberg corrections to the scalar potential. Instead, we consider these ideas from the perspective of the one loop effective Kahler potential. We translate known ideas to this framework and construct convenient formulas for computing individual terms in the expanded effective Kahler potential. We do so for arbitrary R-charge assignments and allow for small R-symmetry violating terms so that both spontaneous and explicit R-symmetry breaking is allowed in our analysis.

  10. Investigating influence of the magnetic arc blow in multi-break vacuum circuit breakers

    Science.gov (United States)

    Liao, Minfu; Ge, Guowei; Duan, Xiongying; Huang, Zhihui; Zou, Jiyan

    2016-12-01

    This paper investigates the influence of the interactive magnetic field in multi-break vacuum circuit breakers (VCBs) on the arc plasma and the post-arc characteristics. The magnetic field of multi-break VCBs is asymmetric and off-center because of the interactive magnetic field, which is also called bias magnetic field (BMF). The BMF distribution of double-break VCBs is gained by electromagnetic analysis. The test circuit of the magnetic arc blow in multi-break VCBs is established by simplifying as the interaction between the vacuum arc and the BMF. The influence of the magnetic arc blow on the arc plasma is studied by the high-speed CMOS camera and the post-arc current measure. While the vacuum arc is in the direction of the Ampere force with the BMF at 200 mT, it is in the retrograde direction when the BMF is below 100 mT, which results in the post-arc charge obviously varying from 9 μC to 50 μC. The relationship between the BMF and the post arc charge is gained. The mechanism of the magnetic arc blow in multi-break VCBs is discussed. Therefore, this paper can provide the base of construct and configuration to avoid the influence of the magnetic arc blow.

  11. Steady state and accident analysis of SCOR (simple compact reactor) with the CATHARE code

    Energy Technology Data Exchange (ETDEWEB)

    Marie-Sophie Chenaud; Guy-Marie Gautier [CEA Cadarache- 13108 St Paul Lez Durance (France)

    2005-07-01

    Full text of publication follows: Within the framework of innovative reactors studies, the CEA was led to propose the SCOR design (Simple Compact Reactor). This design is based on a compact 600 MWe PWR and combines most of the advantages of innovative reactors. All main components such as the pressurizer, the canned pumps, the control rod mechanics and the dedicated heat exchangers on the passive residual heat removal system are integrated in the vessel.The only steam generator is located above the vessel in place of the upper head. The reactor operates at much lower primary circuit pressure than standard PWRs (85 bar instead of the usual 155 bar) and the power density is low (70 MW/m{sup 3} instead of 100 MW/m{sup 3} for the present PWRs). The reactivity being controlled by control rods and burnable poisons, there is no soluble boron. The elimination of a serious LOCA (Loss Of Coolant Accident) and the integrated residual heat removal system lead to enhanced safety with simple safety systems. Main features of the SCOR design and functional parameters have been previously reported. This paper focuses on the safety analysis of SCOR. Thermo hydraulic calculations have been run with the CATHARE code. Some calculations were run with the point kinetics module of CATHARE. Several transient simulations have been assessed. They concern a normal reactor trip from full power operation till refueling shutdown and accidental scenarios such as: - Loss of power, - Breaks from 0.02 m to 0.1 m on circuits connected to the vessel, - Steam generator tubes rupture, - Reactivity insertion by cold shock. Results of transient simulations enable us to conclude upon: - the increase of grace periods in comparison with standard PWRs if no safety systems operate besides emergency shutdown, - the expected efficiency of designed safety systems and in particular of the residual heat removal system in passive configuration even when integrated exchanger are dewatered. It will be retained that

  12. PT-symmetry breaking with divergent potentials: lattice and continuum cases

    CERN Document Server

    Joglekar, Yogesh N; Saxena, Avadh

    2014-01-01

    We investigate the parity- and time-reversal ($\\mathcal{PT}$)-symmetry breaking in lattice models in the presence of long-ranged, non-hermitian, $\\mathcal{PT}$-symmetric potentials that remain finite or become divergent in the continuum limit. By scaling analysis of the fragile $\\mathcal{PT}$ threshold for an open finite lattice, we show that continuum loss-gain potentials $V_\\alpha(x)\\propto i |x|^\\alpha \\mathrm{sign}(x)$ have a positive $\\mathcal{PT}$-breaking threshold for $\\alpha>-2$, and a zero threshold for $\\alpha\\leq -2$. When $\\alpha<0$ localized states with complex (conjugate) energies in the continuum energy-band occur at higher loss-gain strengths. We investigate the signatures of $\\mathcal{PT}$-symmetry breaking in coupled waveguides, and show that the emergence of localized states dramatically shortens the relevant time-scale in the $\\mathcal{PT}$-symmetry broken region.

  13. Measurements of scattering observables for the pd break-up reaction

    Directory of Open Access Journals (Sweden)

    Stephan E.

    2010-04-01

    Full Text Available High-precision measurements of the scattering observables such as cross sections and analyzing powers for the proton-deuteron elastic and break-up reactions have been performed at KVI in the last two decades and elsewhere to investigate various aspects of the three-nucleon force (3NF effects simultaneously. In 2006 an experiment was performed to study these effects in p+d break-up reaction at 135 MeV with the detection system, Big Instrument for Nuclear polarization Analysis, BINA. BINA covers almost the entire kinematical phase space of the break-up reaction. The results are interpreted with the help of state-of-the-art Faddeev calculations and are partly presented in this contribution.

  14. Proton-Deuteron Break-Up Measurements with Bina at 135 MeV

    Science.gov (United States)

    Eslami-Kalantari, M.; Amir-Ahmadi, H. R.; Biegun, A.; Gašparić, I.; Joulaeizadeh, L.; Kalantar-Nayestanaki, N.; Kistryn, St.; Kozela, A.; Mardanpour, H.; Messchendorp, J. G.; Moeini, H.; Ramazani-Moghaddam-Arani, A.; Shende, S. V.; Stephan, E.; Sworst, R.

    High-precision measurements of the proton-deuteron elastic and break-up reaction have been performed in the past at KVI and elsewhere with the aim to study three-nucleon force (3NF) effects. In the present work, we explored 3NF effects in the break-up scattering process by performing a measurement of vector analyzing powers and differential cross sections using a 135 MeV polarized-proton beam impinging on a liquid-deuterium target. For this study, we used a new experimental setup, Big Instrument for Nuclear-polarization Analysis, BINA, which covers almost the entire kinematical phase space of the break-up reaction. The results are interpreted with the help of state-of-the-art Faddeev calculations.

  15. Measurements of scattering observables for the pd break-up reaction

    Science.gov (United States)

    Eslami-Kalantari, M.; Amir-Ahmadi, H. R.; Biegun, A.; Gašparic, I.; Joulaeizadeh, L.; Kalantar-Nayestanaki, N.; Kistryn, St.; Kozela, A.; Mardanpour, H.; Messchendorp, J. G.; Moeini, H.; Ramazani-Moghaddam-Arani, A.; Shende, S. V.; Stephan, E.; Sworst, R.

    2010-04-01

    High-precision measurements of the scattering observables such as cross sections and analyzing powers for the proton-deuteron elastic and break-up reactions have been performed at KVI in the last two decades and elsewhere to investigate various aspects of the three-nucleon force (3NF) effects simultaneously. In 2006 an experiment was performed to study these effects in p+d break-up reaction at 135 MeV with the detection system, Big Instrument for Nuclear polarization Analysis, BINA. BINA covers almost the entire kinematical phase space of the break-up reaction. The results are interpreted with the help of state-of-the-art Faddeev calculations and are partly presented in this contribution.

  16. Measurements of scattering observables for the $pd$ break-up reaction

    CERN Document Server

    Eslami-Kalantari, M; Biegun, A; Gašparic, I; Joulaeizadeh, L; Kalantar-Nayestanaki, N; Kistryn, St; Kozela, A; Mardanpour, H; Messchendorp, J G; Moeini, H; Ramazani-Moghaddam-Arani, A; Shende, S V; Stephan, E; Sworst, R

    2010-01-01

    High-precision measurements of the scattering observables such as cross sections and analyzing powers for the proton-deuteron elastic and break-up reactions have been performed at KVI in the last two decades and elsewhere to investigate various aspects of the three-nucleon force (3NF) effects simultaneously. In 2006 an experiment was performed to study these effects in $\\vec{p}+d$ break-up reaction at 135 MeV with the detection system, Big Instrument for Nuclear polarization Analysis, BINA. BINA covers almost the entire kinematical phase space of the break-up reaction. The results are interpreted with the help of state-of-the-art Faddeev calculations and are partly presented in this contribution.

  17. Detection of a high frequency break in the X-ray power spectrum of Ark 564

    CERN Document Server

    Papadakis, I E; Negoro, H; Gliozzi, M

    2001-01-01

    We present a power spectrum analysis of the long ASCA observation of Ark 564 in June/July 2001. The observed power spectrum covers a frequency range of ~ 3.5 decades. We detect a high frequency break at ~ 0.002 Hz. The power spectrum has an rms of ~30% and a slope of ~ -1 and ~ -2 below and above the break frequency. When combined with the results from a long RXTE observation (Pounds et al. 2001), the observed power spectra of Ark 564 and Cyg X-1 (in the low/hard state) are almost identical, showing a similar shape and rms amplitude. However, the ratio of the high frequency breaks is very small (~ 10e{3-4}), implying that these characteristic frequencies are not indicative of the black hole mass. This result supports the idea of a small black hole mass/high accretion rate in Ark 564.

  18. Quantitative assay of photoinduced DNA strand breaks by real-time PCR.

    Science.gov (United States)

    Wiczk, Justyna; Westphal, Kinga; Rak, Janusz

    2016-09-05

    Real-time PCR (qPCR) - a modern methodology primarily used for studying gene expression has been employed for the quantitative assay of an important class of DNA damage - single strand breaks. These DNA lesions which may lead to highly cytotoxic double strand breaks were quantified in a model system where double stranded DNA was sensitized to UV photons by labeling with 5-bromo-2'-deoxyuridine. The amount of breaks formed due to irradiation with several doses of 320nm photons was assayed by two independent methods: LC-MS and qPCR. A very good agreement between the relative damage measured by the two completely different analytical tools proves the applicability of qPCR for the quantitative analysis of SSBs. Our results suggest that the popularity of the hitherto underestimated though accurate and site-specific technique of real-time PCR may increase in future DNA damage studies.

  19. Dynamical Electroweak Symmetry Breaking in String Models with D-branes

    CERN Document Server

    Kitazawa, Noriaki

    2009-01-01

    The possibility of dynamical electroweak symmetry breaking by strong coupling gauge interaction in models with D-branes in String Theory is examined. Instead of elementary scalar Higgs doublet fields, the gauge symmetry with strong coupling (technicolor) is introduced. As the first step of this direction, a toy model, which is not fully realistic, is concretely analyzed in some detail. The model consists of D-branes and anti-D-branes at orbifold singularities in (T^2 x T^2 x T^2)/Z_3 which preserves supersymmetry. Supersymmetry is broken through the brane supersymmetry breaking. It is pointed out that the problem of large S parameter in dynamical electroweak symmetry breaking scenario may be solved by natural existence of kinetic term mixings between hypercharge U(1) gauge boson and massive anomalous U(1) gauge bosons. The problems to be solved toward constructing more realistic models are clarified in the analysis.

  20. Inertial blob-hole symmetry breaking in magnetised plasma filaments

    CERN Document Server

    Kendl, Alexander

    2015-01-01

    Symmetry breaking between the propagation velocities of magnetised plasma filaments with large positive (blob) and negative (hole) amplitudes, as implied by a dimensional analysis scaling, is studied with global ("full-n") non-Boussinesq gyrofluid computations, which include finite inertia effects through nonlinear polarisation. Interchange blobs on a flat density background have higher inertia and propagate more slowly than holes. In the presence of a large enough density gradient, the effect is reversed: blobs accelerate down the gradient and holes are slowed in their propagation up the gradient. Drift wave blobs spread their initial vorticity rapidly into a fully developed turbulent state, whereas primary holes can remain coherent for many eddy turnover times. The results bear implications for plasma edge zonal flow evolution and tokamak scrape-off-layer transport.