WorldWideScience

Sample records for autoreclosure arc failure

  1. Single-phase AutoReClosure ARC failure on 400 kV combinedcable/overhead line with permanently connected shunt reactor

    DEFF Research Database (Denmark)

    Bak, Claus Leth; Søgaard, Kim

    2008-01-01

    This paper demonstrates the results from a detailed study of the dynamic behavior of a shunt reactor compensated 400 kV combined cable/overhead line. This is accomplished by means of theoretical considerations, simulations and measurements. The work presented here is based on a real-life operatin...

  2. Massive edifice failure at Aleutian arc volcanoes

    Science.gov (United States)

    Coombs, M.L.; White, S.M.; Scholl, D. W.

    2007-01-01

    Along the 450-km-long stretch of the Aleutian volcanic arc from Great Sitkin to Kiska Islands, edifice failure and submarine debris-avalanche deposition have occurred at seven of ten Quaternary volcanic centers. Reconnaissance geologic studies have identified subaerial evidence for large-scale prehistoric collapse events at five of the centers (Great Sitkin, Kanaga, Tanaga, Gareloi, and Segula). Side-scan sonar data collected in the 1980s by GLORIA surveys reveal a hummocky seafloor fabric north of several islands, notably Great Sitkin, Kanaga, Bobrof, Gareloi, Segula, and Kiska, suggestive of landslide debris. Simrad EM300 multibeam sonar data, acquired in 2005, show that these areas consist of discrete large blocks strewn across the seafloor, supporting the landslide interpretation from the GLORIA data. A debris-avalanche deposit north of Kiska Island (177.6?? E, 52.1?? N) was fully mapped by EM300 multibeam revealing a hummocky surface that extends 40??km from the north flank of the volcano and covers an area of ??? 380??km2. A 24-channel seismic reflection profile across the longitudinal axis of the deposit reveals a several hundred-meter-thick chaotic unit that appears to have incised into well-bedded sediment, with only a few tens of meters of surface relief. Edifice failures include thin-skinned, narrow, Stromboli-style collapse as well as Bezymianny-style collapse accompanied by an explosive eruption, but many of the events appear to have been deep-seated, removing much of an edifice and depositing huge amounts of debris on the sea floor. Based on the absence of large pyroclastic sheets on the islands, this latter type of collapse was not accompanied by large eruptions, and may have been driven by gravity failure instead of magmatic injection. Young volcanoes in the central and western portions of the arc (177?? E to 175?? W) are located atop the northern edge of the ??? 4000-m-high Aleutian ridge. The position of the Quaternary stratocones relative to the

  3. The Research of Secondary Arc Spectrum Characteristics on UHV

    Directory of Open Access Journals (Sweden)

    Yunwei Zhao

    2012-10-01

    Full Text Available On UHV power transmission lines, when single-phase ground fault happen, it will appear secondary arc on lines, the existence of secondary arc impact on the stable operation of system. The effectiveness of single-pole autoreclosure (SPAR in maintaining power system stability is largely determined by the speed with which secondary arc extinction, and hence autoreclosure, can be achieved. The paper adopts total harmonic distortion (THD to judge the status of arc. First, the simulation model of secondary arc is established by ATP software. Then, faulted phase voltage and secondary arc are simulated in different close angle. Last, spectrum characteristics and harmonic content of faulted phase voltage and current are analyzed in different close angle, at the same time, THD of non-faulted phase is also analyzed by Fourier algorithm. Through the fault phase voltage and current simulation and Fourier analysis, which comes to the conclusion that at the peak in the power supply voltage secondary arc is the most difficult to extinguish and the harm to insulation is the greatest.

  4. Numerical Algorithm for Distance Protection and Arcing Fault Recognition

    Energy Technology Data Exchange (ETDEWEB)

    Zoran, Radojevic; Park, K. W.; Park, J. S. [LG Industrial Systems, Seoul (Korea)

    2002-07-01

    In this paper a new numerical algorithm for fault distance calculation and arcing fault recognition based on one terminal data and derived in time domain is presented. The algorithm is derived for the case of most frequent single-phase line to ground fault. The faulted phase voltage at the fault place is modeled as a serial connection of fault resistance and a rc voltage. The fault distance and ard voltage amplitude are estimated using Least Error squares Technique. The algorithm can be applied for distance protection, intelligent autoreclosure and for fault location. The results of algorithm tested through computer simulation are given. (author). 6 refs., 6 figs.

  5. Conformal Arc Radiotherapy for Prostate Cancer: Increased Biochemical Failure in Patients With Distended Rectum on the Planning Computed Tomogram Despite Image Guidance by Implanted Markers

    International Nuclear Information System (INIS)

    Purpose: To evaluate the effect of rectal distention on the planning computed tomogram on freedom from biochemical failure (FFBF) of prostate cancer patients treated with image-guided conformal arc radiotherapy. Methods and Materials: The outcomes of 238 patients with T1-T3N0M0 tumors were analyzed, with a median follow-up of 53 months (range, 24-93 months). In 213 patients, daily co-registration of X-rays and digitally reconstructed radiographs was used for positioning, whereas in 25 patients positioning was done using direct prostate visualization with implanted markers. The rectal average cross-sectional area was determined on the planning computed tomogram. Results: The 5-year freedom from Grade 3 to 4 late gastrointestinal and urinary side effect, according to the Radiation Therapy Oncology Group criteria, was 100% and 99.4% respectively. The 5-year FFBF was 88.4%. On multivariate analysis the following variables were significantly related to worse FFBF: risk group according to the National Comprehensive Cancer Network (high- to very high risk vs. intermediate- to low-risk), dose (70 vs. 78 Gy), average cross-sectional area (≥16 vs. 2) and, unexpectedly, the use of implanted markers as opposed to bony structures for patient positioning. In retrospect, the margins around the clinical target volume appeared to be inadequate in the cases in which markers were used. Conclusion: Overall, the outcome of patients treated with image-guided conformal arc radiotherapy is excellent. We were able to confirm the negative prognostic impact of a distended rectum on the planning computed tomogram described by others. The study illustrates the potential danger of image guidance techniques as to margin reduction around the clinical target volume.

  6. 11C choline PET guided salvage radiotherapy with volumetric modulation arc therapy and hypofractionation for recurrent prostate cancer after HIFU failure: preliminary results of tolerability and acute toxicity.

    Science.gov (United States)

    Alongi, Filippo; Liardo, Rocco L E; Iftode, Cristina; Lopci, Egesta; Villa, Elisa; Comito, Tiziana; Tozzi, Angelo; Navarria, Pierina; Ascolese, Anna M; Mancosu, Pietro; Tomatis, Stefano; Bellorofonte, Carlo; Arturo, Chiti; Scorsetti, Marta

    2014-10-01

    The purpose of this work was to evaluate tolerance, feasibility and acute toxicity in patients undergoing salvage radiotherapy after high-intensity focused ultrasound (HIFU) failure. From 2005 to 2011 a total of 15 patients were treated with HIFU as primary radical treatment. Between July 2011 and February 2013, all 15 patients presented biochemical relapse after HIFU and 11C choline PET documenting intrapostatic-only failure. Salvage EBRT was performed with moderate hypofractionation schedule in 28 fractions with volumetric modulation arc therapy (VMAT). Genito-urinary (GU) and rectal and bowel toxicity were scored by common terminology criteria for adverse events version 4 (CTCAE V.4) scale. Biochemical response was assessed by ASTRO Phoenix criteria. Median age of patients was 67 years (range: 53-85). The median Gleason score was 7 (range: 6-9). The median prostate specific antigen (PSA) at the time of biochemical relapse after HIFU was 5.2 ng/mL (range: 2-64.2). Seven of the 15 patients received androgen deprivation therapy (ADT) started after HIFU failure, interrupted before 11C choline PET and radiotherapy. Median prescribed dose was 71.4 Gy (range: 71.4-74.2 Gy) in 28 fractions. No radiation related major upper gastrointestinal (GI), rectal and GU toxicity were experienced. GU, acute grade 1 and grade 2 toxicities were recorded in 7/15 and 4/15 respectively; bowel acute grade 1 and grade 2 toxicities in 4/15 and 1/15; rectal acute grade 1 and grade 2 toxicities in 3/15 and 2/15 respectively. No grade 3 or greater acute or late toxicities occurred. Biochemical control was assessed in 12/15 (80%) patients. With a median follow up of 12 months, three out of 15 patients, with biochemical relapse, showed lymph-nodal recurrence. Our early clinical results and biochemical data confirm the feasibility and show a good tolerance of the 11C choline PET guided salvage radiation therapy after HIFU failure. The findings of low acute toxicity is encouraging, but longer

  7. 11C Choline PET Guided Salvage Radiotherapy with Volumetric Modulation Arc Therapy and Hypofractionation for Recurrent Prostate Cancer after HIFU Failure

    OpenAIRE

    Alongi, Filippo; Liardo, Rocco L. E.; Iftode, Cristina; Lopci, Egesta; Villa, Elisa; Comito, Tiziana; Tozzi, Angelo; Navarria, Pierina; Ascolese, Anna M.; Mancosu, Pietro; Tomatis, Stefano; Bellorofonte, Carlo; Arturo, Chiti; Scorsetti, Marta

    2014-01-01

    The purpose of this work was to evaluate tolerance, feasibility and acute toxicity in patients undergoing salvage radiotherapy after high-intensity focused ultrasound (HIFU) failure. From 2005 to 2011 a total of 15 patients were treated with HIFU as primary radical treatment. Between July 2011 and February 2013, all 15 patients presented biochemical relapse after HIFU and 11C choline PET documenting intrapostatic-only failure. Salvage EBRT was performed with moderate hypofractionation schedul...

  8. Arc Statistics

    CERN Document Server

    Meneghetti, M; Dahle, H; Limousin, M

    2013-01-01

    The existence of an arc statistics problem was at the center of a strong debate in the last fifteen years. With the aim to clarify if the optical depth for giant gravitational arcs by galaxy clusters in the so called concordance model is compatible with observations, several studies were carried out which helped to significantly improve our knowledge of strong lensing clusters, unveiling their extremely complex internal structure. In particular, the abundance and the frequency of strong lensing events like gravitational arcs turned out to be a potentially very powerful tool to trace the structure formation. However, given the limited size of observational and theoretical data-sets, the power of arc statistics as a cosmological tool has been only minimally exploited so far. On the other hand, the last years were characterized by significant advancements in the field, and several cluster surveys that are ongoing or planned for the near future seem to have the potential to make arc statistics a competitive cosmo...

  9. Modeling Arcs

    CERN Document Server

    Insepov, Zeke; Veitzer, Seth; Mahalingam, Sudhakar

    2011-01-01

    Although vacuum arcs were first identified over 110 years ago, they are not yet well understood. We have since developed a model of breakdown and gradient limits that tries to explain, in a self-consistent way: arc triggering, plasma initiation, plasma evolution, surface damage and gra- dient limits. We use simple PIC codes for modeling plasmas, molecular dynamics for modeling surface breakdown, and surface damage, and mesoscale surface thermodynamics and finite element electrostatic codes for to evaluate surface properties. Since any given experiment seems to have more variables than data points, we have tried to consider a wide variety of arcing (rf structures, e beam welding, laser ablation, etc.) to help constrain the problem, and concentrate on common mechanisms. While the mechanisms can be comparatively simple, modeling can be challenging.

  10. Arc saw development report

    International Nuclear Information System (INIS)

    The arc saw is one of the key components of the Contaminated Equipment Volume Reduction (CEVR) Program. This report describes the progress of the arc saw from its inception to its current developmental status. History of the arc saw and early contributors are discussed. Particular features of the arc saw and their advantages for CEVR are detailed. Development of the arc saw including theory of operation, pertinent experimental results, plans for the large arc saw and advanced control systems are covered. Associated topics such as potential applications for the arc saw and other arc saw installations in the world is also touched upon

  11. Rotating arc spark plug

    Science.gov (United States)

    Whealton, John H.; Tsai, Chin-Chi

    2003-05-27

    A spark plug device includes a structure for modification of an arc, the modification including arc rotation. The spark plug can be used in a combustion engine to reduce emissions and/or improve fuel economy. A method for operating a spark plug and a combustion engine having the spark plug device includes the step of modifying an arc, the modifying including rotating the arc.

  12. Peek Arc Consistency

    CERN Document Server

    Bodirsky, Manuel

    2008-01-01

    This paper studies peek arc consistency, a reasoning technique that extends the well-known arc consistency technique for constraint satisfaction. In contrast to other more costly extensions of arc consistency that have been studied in the literature, peek arc consistency requires only linear space and quadratic time and can be parallelized in a straightforward way such that it runs in linear time with a linear number of processors. We demonstrate that for various constraint languages, peek arc consistency gives a polynomial-time decision procedure for the constraint satisfaction problem. We also present an algebraic characterization of those constraint languages that can be solved by peek arc consistency, and study the robustness of the algorithm.

  13. Electric arc hydrogen heaters

    International Nuclear Information System (INIS)

    The experimental data on the electric arc burning in hydrogen are presented. Empirical and semiempirical dependences for calculating the arc characteristics are derived. An engineering method of calculating plasma torches for hydrogen heating is proposed. A model of interaction of a hydrogen arc with a gas flow is outlined. The characteristics of plasma torches for heating hydrogen and hydrogen-bearing gases are described. (author)

  14. Wire + Arc Additive Manufacturing

    OpenAIRE

    Williams, Stewart W.; Martina, Filomeno; Addison, Adrian C.; Ding, Jialuo; Pardal, Goncalo; Colegrove, Paul A.

    2016-01-01

    Depositing large components (>10 kg) in titanium, aluminium, steel and other metals is possible using Wire + Arc Additive Manufacturing. This technology adopts arc welding tools and wire as feedstock for additive manufacturing purposes. High deposition rates, low material and equipment costs, and good structural integrity make Wire+Arc Additive Manufacturing a suitable candidate for replacing the current method of manufacturing from solid billets or large forgings, especially with regards to ...

  15. Tokamak ARC damage

    International Nuclear Information System (INIS)

    Tokamak fusion reactors will have large plasma currents of approximately 10 MA with hundreds of megajoules stored in the magnetic fields. When a major plasma instability occurs, the disruption of the plasma current induces voltage in the adjacent conducting structures, giving rise to large transient currents. The induced voltages may be sufficiently high to cause arcing across sector gaps or from one protruding component to another. This report reviews a tokamak arcing scenario and provides guidelines for designing tokamaks to minimize the possibility of arc damage

  16. Vacuum arc anode phenomena

    International Nuclear Information System (INIS)

    A brief review of anode phenomena in vacuum arcs is presented. Discussed in succession are: the transition of the arc into the anode spot mode; the temperature of the anode before, during and after the anode spot forms; and anode ions. Characteristically the anode spot has a temperature of the order of the atmospheric boiling point of the anode material and is a copious source of vapor and energetic ions. The dominant mechanism controlling the transition of the vacuum arc into the anode spot mode appears to depend upon the electrode geometry, the electrode material, and the current waveform of the particular vacuum arc being considered. Either magnetic constriction in the gap plasma or gross anode melting can trigger the transition; indeed, a combination of the two is a common cause of anode spot formation

  17. Single-Arc IMRT?

    International Nuclear Information System (INIS)

    The idea of delivering intensity-modulated radiation therapy (IMRT) with a multileaf collimator in a continuous dynamic mode during a single rotation of the gantry has recently gained momentum both in research and industry. In this note we investigate the potential of this Single-Arc IMRT technique at a conceptual level. We consider the original theoretical example case from Brahme et al that got the field of IMRT started. Using analytical methods, we derive deliverable intensity 'landscapes' for Single-Arc as well as standard IMRT and Tomotherapy. We find that Tomotherapy provides the greatest flexibility in shaping intensity landscapes and that it allows one to deliver IMRT in a way that comes close to the ideal case in the transverse plane. Single-Arc and standard IMRT make compromises in different areas. Only in relatively simple cases that do not require substantial intensity modulation will Single-Arc be dosimetrically comparable to Tomotherapy. Compared with standard IMRT, Single-Arc could be dosimetrically superior in certain cases if one is willing to accept the spreading of low dose values over large volumes of normal tissue. In terms of treatment planning, Single-Arc poses a more challenging optimization problem than Tomotherapy or standard IMRT. We conclude that Single-Arc holds potential as an efficient IMRT technique especially for relatively simple cases. In very complex cases, Single-Arc may unduly compromise the quality of the dose distribution, if one tries to keep the treatment time below 2 min or so. As with all IMRT techniques, it is important to explore the tradeoff between plan quality and the efficiency of its delivery carefully for each individual case. (note)

  18. ALICE - ARC integration

    OpenAIRE

    Anderlik, Csaba; Gregersen, Anders Rhod; Kleist, Josva; Peters, Andreas; Siaz, Pablo

    2007-01-01

    AliEn or Alice Environment is the Gridware developed and used within the ALICE collaboration for storing and processing data in a distributed manner. ARC (Advanced Resource Connector) is the Grid middleware deployed across the Nordic countries and gluing together the resources within the Nordic Data Grid Facility (NDGF). In this paper we will present our approach to integrate AliEn and ARC, in the sense that ALICE data management and job processing can be carried out on the NDGF infrastructur...

  19. Modeling of Arc Force in Plasma Arc Welding

    Institute of Scientific and Technical Information of China (English)

    GAO Zhonglin; HU Shengsun; YIN Fengliang; WANG Rui

    2008-01-01

    A three. dimensional mathematical model for the transferred-type argon arc was developed to describe arc force on the anode surface. The software ANSYS was employed to solve the model. The model includes a part of torch and tungsten electrode to achieve m ore reasonable results. The arc temperature and flow fields were derived. And the influences of welding parameters on arc force were also studied. The simulated results show that arc pressure at the anode are dependent on the welding current, plasma gas flow rate and electrode neck-in, while not sensitive to arc length.

  20. ALICE-ARC integration

    International Nuclear Information System (INIS)

    AliEn or Alice Environment is the Grid middleware developed and used within the ALICE collaboration for storing and processing data in a distributed manner. ARC (Advanced Resource Connector) is the Grid middleware deployed across the Nordic countries and gluing together the resources within the Nordic Data Grid Facility (NDGF). In this paper we will present our approach to integrate AliEn and ARC, in the sense that ALICE data management and job processing can be carried out on the NDGF infrastructure, using the client tools available in AliEn. The inter-operation has two aspects, one is the data management part and the second the job management aspect. The first aspect was solved by using dCache across NDGF to handle data. Therefore, we will concentrate on the second part. Solving it, was somewhat cumbersome, mainly due to the different computing models employed by AliEn and ARC. AliEN uses an Agent based pull model while ARC handles jobs through the more 'traditional' push model. The solution comes as a module implementing the functionalities necessary to achieve AliEn job submission and management to ARC enabled sites

  1. Consolidating NASA's Arc Jets

    Science.gov (United States)

    Balboni, John A.; Gokcen, Tahir; Hui, Frank C. L.; Graube, Peter; Morrissey, Patricia; Lewis, Ronald

    2015-01-01

    The paper describes the consolidation of NASA's high powered arc-jet testing at a single location. The existing plasma arc-jet wind tunnels located at the Johnson Space Center were relocated to Ames Research Center while maintaining NASA's technical capability to ground-test thermal protection system materials under simulated atmospheric entry convective heating. The testing conditions at JSC were reproduced and successfully demonstrated at ARC through close collaboration between the two centers. New equipment was installed at Ames to provide test gases of pure nitrogen mixed with pure oxygen, and for future nitrogen-carbon dioxide mixtures. A new control system was custom designed, installed and tested. Tests demonstrated the capability of the 10 MW constricted-segmented arc heater at Ames meets the requirements of the major customer, NASA's Orion program. Solutions from an advanced computational fluid dynamics code were used to aid in characterizing the properties of the plasma stream and the surface environment on the calorimeters in the supersonic flow stream produced by the arc heater.

  2. Respiratory Failure

    Science.gov (United States)

    Respiratory failure happens when not enough oxygen passes from your lungs into your blood. Your body's organs, such ... brain, need oxygen-rich blood to work well. Respiratory failure also can happen if your lungs can't ...

  3. The arc sine law and the treasury bill futures market

    OpenAIRE

    Dale, Charles; Workman, Rosemarie

    1980-01-01

    According to the so-called "arc sine law," mechanical trading rules applied to price movements in financial assets will result in long periods of cumulative success, but equally long periods of cumulative failure. The long periods of success will tempt investors to apply trading rules to actual decisions. The long periods of failure make it very likely that such application will eventually blow them out of the market.

  4. Gas Tungsten Arc Welding of Copper and Mild Steel

    OpenAIRE

    Daniel T; Timotius P; Maziar R

    2016-01-01

    In this paper, copper and mild steel were welded using a gas tungsten arc welding (GTAW) process. To determine the weldablity factor, tests are needed to provide information on mechanical strength, potential defects in structure, and nature of failure. Mechanical testing included transverse tensile tests, micro hardness tests, and bend tests. The results for the transverse tensile test revealed failure occurred at the copper heat affected zone (HAZ) with an ultimate tensile strength of 220MPa...

  5. Arc Plasma Torch Modeling

    CERN Document Server

    Trelles, J P; Vardelle, A; Heberlein, J V R

    2013-01-01

    Arc plasma torches are the primary components of various industrial thermal plasma processes involving plasma spraying, metal cutting and welding, thermal plasma CVD, metal melting and remelting, waste treatment and gas production. They are relatively simple devices whose operation implies intricate thermal, chemical, electrical, and fluid dynamics phenomena. Modeling may be used as a means to better understand the physical processes involved in their operation. This paper presents an overview of the main aspects involved in the modeling of DC arc plasma torches: the mathematical models including thermodynamic and chemical non-equilibrium models, turbulent and radiative transport, thermodynamic and transport property calculation, boundary conditions and arc reattachment models. It focuses on the conventional plasma torches used for plasma spraying that include a hot-cathode and a nozzle anode.

  6. Thermal Arc Spray Overview

    Science.gov (United States)

    Hafiz Abd Malek, Muhamad; Hayati Saad, Nor; Kiyai Abas, Sunhaji; Mohd Shah, Noriyati

    2013-06-01

    Usage of protective coating for corrosion protection was on highly demand during the past decade; and thermal spray coating played a major part during that time. In recent years, the thermal arc spray coating becomes a popular coating. Many big players in oil and gas such as PETRONAS, EXXON MOBIL and SHELL in Malaysia tend to use the coating on steel structure as a corrosion protection. Further developments in coating processes, the devices, and raw materials have led to expansion of functional coatings and applications scope from conventional coating to specialized industries. It is widely used because of its ability to withstand high process temperature, offer advantages in efficiency, lower cost and acts as a corrosion protection. Previous research also indicated that the thermal arc spray offers better coating properties compared to other methods of spray. This paper reviews some critical area of thermal spray coating by discussing the process/parameter of thermal arc spray technology and quality control of coating. Coating performance against corrosion, wear and special characteristic of coating are also described. The field application of arc spray technology are demonstrated and reviewed.

  7. Thermal Arc Spray Overview

    International Nuclear Information System (INIS)

    Usage of protective coating for corrosion protection was on highly demand during the past decade; and thermal spray coating played a major part during that time. In recent years, the thermal arc spray coating becomes a popular coating. Many big players in oil and gas such as PETRONAS, EXXON MOBIL and SHELL in Malaysia tend to use the coating on steel structure as a corrosion protection. Further developments in coating processes, the devices, and raw materials have led to expansion of functional coatings and applications scope from conventional coating to specialized industries. It is widely used because of its ability to withstand high process temperature, offer advantages in efficiency, lower cost and acts as a corrosion protection. Previous research also indicated that the thermal arc spray offers better coating properties compared to other methods of spray. This paper reviews some critical area of thermal spray coating by discussing the process/parameter of thermal arc spray technology and quality control of coating. Coating performance against corrosion, wear and special characteristic of coating are also described. The field application of arc spray technology are demonstrated and reviewed.

  8. ALICE: ARC integration

    CERN Document Server

    Anderlik, C; Kleist, J; Peters, A; Saiz, P

    2008-01-01

    AliEn or Alice Environment is the Grid middleware developed and used within the ALICE collaboration for storing and processing data in a distributed manner. ARC (Advanced Resource Connector) is the Grid middleware deployed across the Nordic countries and gluing together the resources within the Nordic Data Grid Facility (NDGF). In this paper we will present our approach to integrate AliEn and ARC, in the sense that ALICE data management and job processing can be carried out on the NDGF infrastructure, using the client tools available in AliEn. The inter-operation has two aspects, one is the data management part and the second the job management aspect. The first aspect was solved by using dCache across NDGF to handle data. Therefore, we will concentrate on the second part. Solving it, was somewhat cumbersome, mainly due to the different computing models employed by AliEn and ARC. AliEN uses an Agent based pull model while ARC handles jobs through the more 'traditional' push model. The solution comes as a modu...

  9. Kidney Failure

    Science.gov (United States)

    ... Health Information > Health Communication Programs > National Kidney Disease Education Program > Learn About Kidney Disease > Living With Kidney Disease > Kidney Failure | Share External Link Disclaimer Living With Kidney Disease ...

  10. Semicircular Rashba arc spin polarizer

    International Nuclear Information System (INIS)

    In this work, we study the generation of spin polarized currents using curved arcs of finite widths, in which the Rashba spin orbit interaction (RSOI) is present. Compared to the 1-dimensional RSOI arcs with zero widths studied previously, the finite width presents charge carriers with another degree of freedom along the transverse width of the arc, in addition to the longitudinal degree of freedom along the circumference of the arc. The asymmetry in the transverse direction due to the difference in the inner and outer radii of the arc breaks the antisymmetry of the longitudinal spin z current in a straight RSOI segment. This property can be exploited to generate spin z polarized current output from the RSOI arc by a spin unpolarized current input. The sign of the spin current can be manipulated by varying the arc dimensions

  11. Semicircular Rashba arc spin polarizer

    Energy Technology Data Exchange (ETDEWEB)

    Bin Siu, Zhuo, E-mail: a0018876@nus.edu.sg [NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456 (Singapore); Advanced Concepts and Nanotechnology, Data Storage Institute, DSI Building, 5 Engineering Drive 1 (Off Kent Ridge Crescent, NUS), Singapore 117608 (Singapore); Jalil, Mansoor B. A. [NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456 (Singapore); Ghee Tan, Seng [Advanced Concepts and Nanotechnology, Data Storage Institute, DSI Building, 5 Engineering Drive 1 (Off Kent Ridge Crescent, NUS), Singapore 117608 (Singapore)

    2014-05-07

    In this work, we study the generation of spin polarized currents using curved arcs of finite widths, in which the Rashba spin orbit interaction (RSOI) is present. Compared to the 1-dimensional RSOI arcs with zero widths studied previously, the finite width presents charge carriers with another degree of freedom along the transverse width of the arc, in addition to the longitudinal degree of freedom along the circumference of the arc. The asymmetry in the transverse direction due to the difference in the inner and outer radii of the arc breaks the antisymmetry of the longitudinal spin z current in a straight RSOI segment. This property can be exploited to generate spin z polarized current output from the RSOI arc by a spin unpolarized current input. The sign of the spin current can be manipulated by varying the arc dimensions.

  12. Arc cathode spots

    International Nuclear Information System (INIS)

    Arc spots are usually highly unstable and jump statistically over the cathode surface. In a magnetic field parallel to the surface, preferably they move in the retrograde direction; i.e., opposite to the Lorentzian rule. If the field is inclined with respect to the surface, the spots drift away at a certain angle with respect to the proper retrograde direction (Robson drift motion). These well-known phenomena are explained by one stability theory

  13. Vacuum Arc Ion Sources

    OpenAIRE

    Brown, I.

    2014-01-01

    The vacuum arc ion source has evolved into a more or less standard laboratory tool for the production of high-current beams of metal ions, and is now used in a number of different embodiments at many laboratories around the world. Applications include primarily ion implantation for material surface modification research, and good performance has been obtained for the injection of high-current beams of heavy-metal ions, in particular uranium, into particle accelerators. As the use of the sourc...

  14. Circular arc structures

    KAUST Repository

    Bo, Pengbo

    2011-07-01

    The most important guiding principle in computational methods for freeform architecture is the balance between cost efficiency on the one hand, and adherence to the design intent on the other. Key issues are the simplicity of supporting and connecting elements as well as repetition of costly parts. This paper proposes so-called circular arc structures as a means to faithfully realize freeform designs without giving up smooth appearance. In contrast to non-smooth meshes with straight edges where geometric complexity is concentrated in the nodes, we stay with smooth surfaces and rather distribute complexity in a uniform way by allowing edges in the shape of circular arcs. We are able to achieve the simplest possible shape of nodes without interfering with known panel optimization algorithms. We study remarkable special cases of circular arc structures which possess simple supporting elements or repetitive edges, we present the first global approximation method for principal patches, and we show an extension to volumetric structures for truly threedimensional designs. © 2011 ACM.

  15. Arc-preserving subsequences of arc-annotated sequences

    CERN Document Server

    Popov, Vladimir Yu

    2011-01-01

    Arc-annotated sequences are useful in representing the structural information of RNA and protein sequences. The longest arc-preserving common subsequence problem has been introduced as a framework for studying the similarity of arc-annotated sequences. In this paper, we consider arc-annotated sequences with various arc structures. We consider the longest arc preserving common subsequence problem. In particular, we show that the decision version of the 1-{\\sc fragment LAPCS(crossing,chain)} and the decision version of the 0-{\\sc diagonal LAPCS(crossing,chain)} are {\\bf NP}-complete for some fixed alphabet $\\Sigma$ such that $|\\Sigma| = 2$. Also we show that if $|\\Sigma| = 1$, then the decision version of the 1-{\\sc fragment LAPCS(unlimited, plain)} and the decision version of the 0-{\\sc diagonal LAPCS(unlimited, plain)} are {\\bf NP}-complete.

  16. Hybrid laser-arc welding

    DEFF Research Database (Denmark)

    Hybrid laser-arc welding (HLAW) is a combination of laser welding with arc welding that overcomes many of the shortfalls of both processes. This important book gives a comprehensive account of hybrid laser-arc welding technology and applications. The first part of the book reviews...... the characteristics of the process, including the properties of joints produced by hybrid laser-arc welding and ways of assessing weld quality. Part II discusses applications of the process to such metals as magnesium alloys, aluminium and steel as well as the use of hybrid laser-arc welding in such sectors as ship...... building and the automotive industry. With its distinguished editor and international team of contributors, Hybrid laser-arc welding, will be a valuable source of reference for all those using this important welding technology. Professor Flemming Ove Olsen works in the Department of Manufacturing...

  17. Heart Failure

    Science.gov (United States)

    ... blood. In other cases, the heart can't pump blood to the rest of the body with enough ... failure affects the right side, the heart cannot pump enough blood to the lungs, where it picks up oxygen. ...

  18. Heart Failure

    Science.gov (United States)

    ... together. About Rise Above HF Rise Above Heart Failure seeks to increase the dialogue about HF and improve the lives of people affected by the condition through awareness, education and support. Through the initiative, AHA strives to ...

  19. Respiratory Failure

    OpenAIRE

    Özyılmaz, Ezgi

    2014-01-01

    The main function of the lungs is to maintain the exchange between the pulmonary capillary and the air in the alveoli. By this way, the arteriel oxygen and carbondioxide tension remains constant. Respiratory failure is a syndrome which is defined as the loss of the ability of respiratory system to exchange oxygen and carbondioxide elimination function. The main pathophysiological causes of respiratory failure include ventilation-perfusion mismatch, alveolar hypoventilation, impaired diffusion...

  20. Gas tungsten arc welder

    International Nuclear Information System (INIS)

    A welder for automated closure of fuel pins by a gas tungsten arc process in which a rotating length of cladding is positioned adjacent a welding electrode in a sealed enclosure. An independently movable grinder, co-axial with the electrode, is provided in the enclosure for refurbishing the used electrode between welds. The specification also discloses means for loading of the cladding with fuel pellets and for placement of reflectors, gas capsules and end caps. Gravity feed conveyor and inerting means are also described. (author)

  1. Electric arc welding gun

    Science.gov (United States)

    Luttrell, Edward; Turner, Paul W.

    1978-01-01

    This invention relates to improved apparatus for arc welding an interior joint formed by intersecting tubular members. As an example, the invention is well suited for applications where many similar small-diameter vertical lines are to be welded to a long horizontal header. The improved apparatus includes an arc welding gun having a specially designed welding head which is not only very compact but also produces welds that are essentially free from rolled-over solidified metal. The welding head consists of the upper end of the barrel and a reversely extending electrode holder, or tip, which defines an acute angle with the barrel. As used in the above-mentioned example, the gun is positioned to extend upwardly through the vertical member and the joint to be welded, with its welding head disposed within the horizontal header. Depending on the design of the welding head, the barrel then is either rotated or revolved about the axis of the vertical member to cause the electrode to track the joint.

  2. Of Eggs and Arcs

    Science.gov (United States)

    Burns, Joseph A.; Thomas, P. C.; Helfenstein, P.; Tiscareno, M. S.; Hedman, M. M.; Agarwal, M.

    2012-10-01

    New scenarios for the origins of Saturn’s rings/interior moons have directed scientific attention to the region just exterior to Saturn’s main rings. Four satellites (Aegaeon = Ae; Anthe = An; Methone = Me; Pallene = Pa) discovered by the Cassini mission on either side of Mimas’s orbit perhaps comprise a distinct class of ring-moon. They are tiny (R = 0.3-2.5 km); three (AeAnMe) are trapped in co-rotation resonances with Mimas and reside within ring-arcs; and at least two (MePa) have remarkably regular shapes. Images with pixel scales as fine as 27 m taken in May 2012 reveal Methone to be ovoid within 10 m (from sub-pixel limb detection) and devoid of any craters (>130 m) across its 9 km2 of surface; Pallene and even tiny Aegaeon have similar appearances in lesser-quality images. Numerical simulations demonstrate that particles comprising the surrounding ring-arcs populate the same resonances as their embedded moons; escape speeds from the moons are bodies. In this environment, the moons’ shapes are smooth equipotentials; electrostatic effects may also determine how grains settle to surfaces. Considering these shapes to represent equipotential surfaces for rotating, tidally distorted, homogeneous bodies, we infer mean satellite densities of 250+/-60 (Pa), 310+/-30 (Me), and 540+/-120 (Ae) kg m-3. About half of Methone’s leading hemisphere is covered by a sharply bounded, lemon-shaped, relatively dark region, having a form reminiscent of Mimas’s thermal anomaly (Howett et al. 2011). Its (601 nm) albedo is 13% lower than the bounding brighter material. An irregularly shaped, even-darker (by 4%) blotch straddles the apex of the moon’s motion. Impacts with circum-planetary meteoroids and plasma are likely responsible for these features.

  3. Heart failure

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    2009170 Curcumin attenuates left ventricular dysfunction and remodeling in rabbits with chronic heart failure. TANG Yanhong(唐艳红),et al.Dept Cardiol,Renmin Hosp,Wuhan Univ,Wuhan 430060.Chin J Cardiol,2009;37(3):262-267.

  4. Failure Modes

    DEFF Research Database (Denmark)

    Jakobsen, K. P.; Burcharth, H. F.; Ibsen, Lars Bo; Sørensen, John Dalsgaard

    1999-01-01

    The present appendix contains the derivation of ten different limit state equations divided on three different failure modes. Five of the limit state equations can be used independently of the characteristics of the subsoil, whereas the remaining five can be used for either drained or undrained s...

  5. Heart failure

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    970284 Effects of enalapril on heart rate variabilityin patients with congestive heart failure. ZHANGYouhua(章友华), et a1. Dept Cardiol, Cardiovasc Instit& Fuwai Hosp, CAMS & PUMC, Beijing, 100037. ChinCir J 1996; 11(2): 729-732.

  6. Respiratory Failure

    Directory of Open Access Journals (Sweden)

    Ezgi Ozyilmaz

    2014-06-01

    Full Text Available The main function of the lungs is to maintain the exchange between the pulmonary capillary and the air in the alveoli. By this way, the arteriel oxygen and carbondioxide tension remains constant. Respiratory failure is a syndrome which is defined as the loss of the ability of respiratory system to exchange oxygen and carbondioxide elimination function. The main pathophysiological causes of respiratory failure include ventilation-perfusion mismatch, alveolar hypoventilation, impaired diffusion capacity and increased shunt. A number of diseases may result in respiratory failure by different pathophysiological reasons. The most common causes are Type 1 (hypoxemic and Type 2 (hypercapnic respiratory failure. When suspected with clinical signs and symptoms, the diagnosis should be confirmed with arterial blood gases. At this step, other diagnostic interventions, which could be performed, may be used to enlighten the underlying pathophysiological cause. Although the main therapeutic approach is similar, specific treatment are also required based on the underlying cause. The basic pathophysiological points, diagnosis and basic treatment approach have been evaluated in this review article. [Cukurova Med J 2014; 39(3.000: 428-442

  7. Arc Interference Behavior during Twin Wire Gas Metal Arc Welding Process

    Directory of Open Access Journals (Sweden)

    Dingjian Ye

    2013-01-01

    Full Text Available In order to study arc interference behavior during twin wire gas metal arc welding process, the synchronous acquisition system has been established to acquire instantaneous information of arc profile including dynamic arc length variation as well as relative voltage and current signals. The results show that after trailing arc (T-arc is added to the middle arc (M-arc in a stable welding process, the current of M arc remains unchanged while the agitation increases; the voltage of M arc has an obvious increase; the shape of M arc changes, with increasing width, length, and area; the transfer frequency of M arc droplet increases and the droplet itself becomes smaller. The wire extension length of twin arc turns out to be shorter than that of single arc welding.

  8. High current electric arcs; Les arcs electriques a fort courant

    Energy Technology Data Exchange (ETDEWEB)

    Delalondre, C.; Simonin, O. [Electricite de France (EDF), 78 - Chatou (France). Lab. National d' Hydraulique; Mineau, L. [Electricite de France (EDF), 75 - Paris (France). Dept. Systemes Energetiques; Verite, J.C. [Electricite de France (EDF), 75 - Paris (France). Dept. Cables, Condensateurs, Materiel d' Automatisme et Materiaux

    1999-07-01

    The mechanisms called into play through the interaction between a high current electric arc and the surrounding environment have an essential role to play in the performance of arc furnaces and high voltage circuit breakers. Our knowledge of them remains poor, and because of the very high temperatures and speeds involved, experimental investigation is particularly difficult. What can numerical modelling teach us about these phenomena? (authors)

  9. Failure Analysis

    International Nuclear Information System (INIS)

    After ten years of operation at the Atucha I Nuclear Power Station a gear belonging to a pressurized heavy water reactor refuelling machine, failed. The gear box was used to operate the inlet-outlet heavy-water valve of the machine. Visual examination of the gear device showed an absence of lubricant and that several gear teeth were broken at the root. Motion was transmitted with a speed-reducing device with controlled adjustable times in order to produce a proper fitness of the valve closure. The aim of this paper is to discuss the results of the gear failure analysis in order to recommend the proper solution to prevent further failures. (Author)

  10. Renal failure

    Institute of Scientific and Technical Information of China (English)

    1993-01-01

    930150 Epidermal growth factor and its recep-tor in the renal tissue of patients with acute re-nal failure and normal persons.LIU Zhihong(刘志红),et al.Jinling Hosp,Nanjing,210002.Natl Med J China 1992;72(10):593-595.Epidermal growth factor(EGF)and its receptor(EGF-R)were identified by immunohis-tochemical method(4 layer PAP)in the renaltissue specimens obtained from 11 normal kid-neys and 17 cases of acute renal failure(ARF).The quantitative EGF and EGF-R in the tissuewere expressed as positive tubules per mm~2.The amount of EGF and EGF-R in renal tissue

  11. Renal failure

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    2008463 Protective effect of recombination rat augmenter of liver regeneration on kidney in acute renal failure rats. TANG Xiaopeng(唐晓鹏), et al. Dept Nephrol, 2nd Affili Hosp Chongqing Med Univ, Chongqing 400010.Chin J Nephrol 2008;24(6):417-421. Objective To investigate the protective effects of recombination rat augmenter of liver regeneration (rrALR) on tubular cell injury and renal dysfunction

  12. Heart failure

    Institute of Scientific and Technical Information of China (English)

    1992-01-01

    920647 Comparative effects of commonvasodilators on experimental cardiac fai-lure. LI Zhijian (李志坚), et al. Dept Cardiol,2nd Hosp, Tianjin Med Coll. Tianjin Med J1992; 20(8): 456-458. A 9×9 latin square design was employed forcomparing the effects of (1) placebo, (2) nitr-oprusside, (3) phentolamine, (4) isosorbide dini-trate. (5) captopril, (6) captopril-isosorbide

  13. STUDY ON THE PRESSURE IN PLASMA ARC

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The axial pressure in plasma arc is measured under different conditions. The effects of the parameters, such as welding current, plasma gas flow rate, electrode setback and arc length, on the pressure in plasma arc are investigated and quantitative analyzed to explain the relationship between the quality of weld and the matching of parameters in plasma arc welding process.

  14. Thomson scattering diagnostics of decay processes of Ar/SF6 gas-blast arcs confined by a nozzle

    International Nuclear Information System (INIS)

    Because of its instability, it is difficult to measure precisely the electron density (ne) of a long-gap decaying arc discharge in a circuit breaker. However, it is well known that it is an essential parameter for the determination of success or failure of the current interruption in a circuit breaker. In this paper, the spatiotemporal evolutions of the electron density were successfully measured in decaying SF6 gas-blast arc discharges formed with a long gap (50 mm) in a confined nozzle using laser Thomson scattering. Pure Ar gas and an 80%Ar/20%SF6 mixture gas were used as the arc quenching media at atmospheric pressure. After reducing the current to zero, both the measured ne and arc radius in the Ar/SF6 gas arc clearly decayed more rapidly than in the pure Ar gas arc. (fast track communication)

  15. Dosimetric and delivery characterizations of full-arc and half-arc volumetric-modulated arc therapy for maxillary cancer

    International Nuclear Information System (INIS)

    We compared the efficiency and accuracy of full-arc and half-arc volumetric-modulated arc therapy (VMAT) delivery for maxillary cancer. Plans for gantry rotation angles of 360deg and 180deg (full-arc and half-arc VMAT) were created for six maxillary cancer cases with the Monaco treatment planning system, and delivered using an Elekta Synergy linear accelerator. Full-arc and half-arc VMAT were compared with regard to homogeneity index (HI), conformity index (CI), mean dose to normal brain, total monitor units (MU), delivery times, root mean square (r.m.s.) gantry accelerations (deg/s2), and r.m.s. gantry angle errors (deg). The half-arc VMAT plans achieved comparable HI and CI to the full-arc plans. Mean doses to the normal brain and brainstem with the half-arc VMAT plans were on average 16% and 17% lower than those with the full-arc VMAT plans. For other organs at risk (OARs), no significant dose volume histogram (DVH) differences were observed between plans. Half-arc VMAT resulted in 11% less total MU and 20% shorter delivery time than the full-arc VMAT, while r.m.s. gantry acceleration and r.m.s. gantry angle error during half-arc VMAT delivery were 30% and 23% less than those during full-arc VMAT delivery, respectively. Furthermore, the half-arc VMAT plans were comparable with the full-arc plans regarding dose homogeneity and conformity in maxillary cancer, and provided a statistical decrease in mean dose to OAR, total MU, delivery time and gantry angle error. Half-arc VMAT plans may be a suitable treatment option in radiotherapy for maxillary cancer. (author)

  16. Arcing phenomena in fusion devices workshop

    International Nuclear Information System (INIS)

    The workshop on arcing phenomena in fusion devices was organized (1) to review the pesent status of our understanding of arcing as it relates to confinement devices, (2) to determine what informaion is needed to suppress arcing and (3) to define both laboratory and in-situ experiments which can ultimately lead to reduction of impurities in the plasma caused by arcing. The workshop was attended by experts in the area of vacuum arc electrode phenomena and ion source technology, materials scientists, and both theoreticians and experimentalists engaged in assessing the importance of unipolar arcing in today's tokamaks. Abstracts for papers presented at the workshop are included

  17. Arcing phenomena in fusion devices workshop

    Energy Technology Data Exchange (ETDEWEB)

    Clausing, R.E.

    1979-01-01

    The workshop on arcing phenomena in fusion devices was organized (1) to review the pesent status of our understanding of arcing as it relates to confinement devices, (2) to determine what informaion is needed to suppress arcing and (3) to define both laboratory and in-situ experiments which can ultimately lead to reduction of impurities in the plasma caused by arcing. The workshop was attended by experts in the area of vacuum arc electrode phenomena and ion source technology, materials scientists, and both theoreticians and experimentalists engaged in assessing the importance of unipolar arcing in today's tokamaks. Abstracts for papers presented at the workshop are included.

  18. High Voltage Solar Array Arc Testing for a Direct Drive Hall Effect Thruster System

    Science.gov (United States)

    Schneider, Todd; Carruth, M. R., Jr.; Vaughn, J. A.; Jongeward, G. A.; Mikellides, I. G.; Ferguson, D.; Kerslake, T. W.; Peterson, T.; Snyder, D.; Hoskins, A.

    2004-01-01

    The deleterious effects of spacecraft charging are well known, particularly when the charging leads to arc events. The damage that results from arcing can severely reduce system lifetime and even cause critical system failures. On a primary spacecraft system such as a solar array, there is very little tolerance for arcing. Motivated by these concerns, an experimental investigation was undertaken to determine arc thresholds for a high voltage (200-500 V) solar array in a plasma environment. The investigation was in support of a NASA program to develop a Direct Drive Hall-Effect Thruster (D2HET) system. By directly coupling the solar array to a Hall-effect thruster, the D2HET program seeks to reduce mass, cost and complexity commonly associated with the power processing in conventional power systems. In the investigation, multiple solar array technologies and configurations were tested. The cell samples were biased to a negative voltage, with an applied potential difference between them, to imitate possible scenarios in solar array strings that could lead to damaging arcs. The samples were tested in an environment that emulated a low-energy, HET-induced plasma. Short duration trigger arcs as well as long duration sustained arcs were generated. Typical current and voltage waveforms associated with the arc events are presented. Arc thresholds are also defined in terms of voltage, current and power. The data will be used to propose a new, high-voltage (greater than 300 V) solar array design for which the likelihood of damage from arcing is minimal.

  19. Minor arcs for Goldbach's problem

    OpenAIRE

    Helfgott, H. A.

    2012-01-01

    The ternary Goldbach conjecture states that every odd number n>=7 is the sum of three primes. The estimation of sums of the form \\sum_{p\\leq x} e(\\alpha p), \\alpha = a/q + O(1/q^2), has been a central part of the main approach to the conjecture since (Vinogradov, 1937). Previous work required q or x to be too large to make a proof of the conjecture for all n feasible. The present paper gives new bounds on minor arcs and the tails of major arcs. This is part of the author's proof of the ternar...

  20. Total Marrow Irradiation With RapidArc Volumetric Arc Therapy

    International Nuclear Information System (INIS)

    Purpose: To develop a volumetric arc therapy (VMAT)-total marrow irradiation (TMI) technique for patients with hematologic malignancies. Methods and Materials: VMAT planning was performed for 6 patients using RapidArc technology. The planning target volume consisted of all the bones in the body from the head to the mid-femur, excluding the extremities, except for the humerus, plus a 3.0-mm margin. The organs at risk included the lungs, heart, liver, kidneys, bowels, brain, eyes, and oral cavity. The VMAT-TMI technique consisted of three plans: the head and neck, the chest, and the pelvis, each with three 330o arcs. The plans were prescribed to ensure, at a minimum, 95% planning target volume dose coverage with the prescription dose (percentage of volume receiving dose of ≥12 Gy was 95%). The treatments were delivered and verified using MapCheck and ion chamber measurements. Results: The VMAT-TMI technique reported in the present study provided comparable dose distributions with respect to the fixed gantry linear accelerator intensity-modulated TMI. RapidArc planning was less subjective and easier, and, most importantly, the delivery was more efficient. RapidArc reduced the treatment delivery time to approximately 18 min from 45 min with the fixed gantry linear accelerator intensity-modulated TMI. When the prescription dose coverage was reduced to 85% from 95% and the mandible and maxillary structures were not included in the planning target volume as reported in a tomotherapy study, a considerable organ at risk dose reduction of 4.2-51% was observed. The average median dose for the lungs and lenses was reduced to 5.6 Gy from 7.2 Gy and 2.4 Gy from 4.5 Gy, respectively. Conclusion: The RapidArc VMAT technique improved the treatment planning, dose conformality, and, most importantly, treatment delivery efficiency. The results from our study suggest that the RapidArc VMAT technology can be expected to facilitate the clinical transition of TMI.

  1. Axisymmetric arc in a supersonic nozzle

    International Nuclear Information System (INIS)

    Axisymmetric arc burning in a supersonic nozzle has wide technical applications (eg in gas blast circuit breaker, arc heaters etc.). Mathematical modelling of such an arc is usually based on boundary-layer assumption which assumes a known pressure distribution imposed on the arc or based on the integral method of arc analysis. Thus, the flow outside of the arc's thermal influence is assumed to be one dimensional. In practice, this is not the case as the nozzle is not sufficiently gentle in the axial direction or the presence of the upstream electrode makes the assumption of one-dimensional flow invalid. The purpose of the present investigation is to model the arc based on Navier-Stokes equations which are modified to take into account of electrical power input and radiation transport. The arcing gas is SF6, the transport properties of which (electrical conductivity, viscosity, thermal conductivity etc.) are highly nonlinear functions of temperature but only weakly dependent on the pressure

  2. Craniospinal irradiation using Rapid Arc

    Energy Technology Data Exchange (ETDEWEB)

    Fandino, J. M.; Silva, M. C.; Marino, A.; Candal, A.; Diaz, I.; Fernandez, C.; Gesto, C.; Izquierdo, P.; Losada, C.; Poncet, M.; Soto, M.; Triana, G.

    2013-07-01

    Cranio-Spinal Irradiation is technically very challenging, historically field edge matching is needed because of the mechanical limitations of standard linear accelerators. The purpose of this study is to assess the Volumetric Arc Therapy as a competitive technique for Cranio-Spinal Irradiation compared to the conventional 3D Conformal Radiotherapy technique. (Author)

  3. A rotating arc plasma invertor

    International Nuclear Information System (INIS)

    A device is described for the inversion of direct current to alternating current. The main feature is the use of a rotating plasma arc in crossed electric and magnetic fields as a switch. This device may provide an economic alternative to other inversion methods in some circumstances

  4. The next-generation ARC middleware

    DEFF Research Database (Denmark)

    Appleton, O.; Cameron, D.; Cernak, J.;

    2010-01-01

    The Advanced Resource Connector (ARC) is a light-weight, non-intrusive, simple yet powerful Grid middleware capable of connecting highly heterogeneous computing and storage resources. ARC aims at providing general purpose, flexible, collaborative computing environments suitable for a range of uses...... the next-generation ARC middleware, implemented as Web Services with the aim of standard-compliant interoperability....

  5. Stability of alternating current gliding arcs

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Salewski, Mirko; Leipold, Frank;

    2014-01-01

    on Ohm’s law indicates that the critical length of alternating current (AC) gliding arc discharge columns can be larger than that of a corresponding direct current (DC) gliding arc. This finding is supported by previously published images of AC and DC gliding arcs. Furthermore, the analysis shows...

  6. Making Conductive Polymers By Arc Tracking

    Science.gov (United States)

    Daech, Alfred F.

    1992-01-01

    Experimental technique for fabrication of electrically conductive polymeric filaments based on arc tracking, in which electrical arc creates conductive carbon track in material that initially was insulator. Electrically conductive polymeric structures made by arc tracking aligned along wire on which formed. Alignment particularly suited to high conductivity and desirable in materials intended for testing as candidate superconductors.

  7. Relationship between arc voltage current and arc length in TIG welding

    International Nuclear Information System (INIS)

    The relationship between arc voltage, arc length and current in Tungsten Inert Gas welding has been investigated. It was not possible to determine a correlation between arc voltage, current and arc length because of the inherent variability in the experimental results. A typical value for the error in controlling the arc length using arc voltage was calculated and found to be ± 0.5mm. The variation in arc voltage at constant conditions has two components, long term and short term. Long term is the variation in voltage between welds, short term is voltage variation within a few seconds. Both are about 5% of the total arc voltage. Since only a fraction of the arc voltage depends on arc length, this leads to a much larger variation in arc length if Arc Voltage Control (AVC) is used to control arc length (about 15% in each case at 3mm arc length). A weld procedure based on AVC is likely to yield a different variability in weld bead geometry from one based on constant arc length. (author)

  8. Simulation of Magnetically Dispersed Arc Plasma

    Institute of Scientific and Technical Information of China (English)

    白冰; 查俊; 张晓宁; 王城; 夏维东

    2012-01-01

    Magnetically dispersed arc plasma exhibits typically dispersed uniform arc column as well as diffusive cathode root and diffusive anode root. In this paper magnetically dispersed arc plasma coupled with solid cathode is numerically simulated by the simplified cathode sheath model of LOWKE . The numerical simulation results in argon show that the maximum value of arc root current density on the cathode surface is 3.5×10^7 A/m^2), and the maximum value of energy flux on the cathode surface is 3× 10^7 J/m^2, both values are less than the average values of a contracted arc, respectively.

  9. A mechanism that triggers double arcing during plasma arc cutting

    Energy Technology Data Exchange (ETDEWEB)

    Nemchinsky, Valerian, E-mail: nemchinsky@bellsouth.ne [Keiser University, Fort Lauderdale, FL 33309 (United States)

    2009-10-21

    Double arcing (DA) is a phenomenon when a transferred arc, flowing inside an electrically insulated nozzle, breaks into two separate arcs: one that connects the cathode and the nozzle and another that connects the nozzle and a work-piece. It is a commonly accepted opinion that the reason for DA is high voltage drop in the plasma inside the nozzle. However, the specific mechanism that triggers the DA development is not clear. In this paper, we propose such a mechanism. Dielectric films deposited inside the nozzle's orifice play the key role in this mechanism. These films are charged by ion current from plasma. A strong electric field is created inside the film and at the boundary of the film and clean metal of the nozzle. This gives rise to a thermo-field electron emission from the clean metal that borders the film. Emitted electrons are accelerated at the voltage drop between the nozzle and plasma. These electrons produce extra ions, which in turn move back to the film and additionally charge it. This sequence of events leads to explosive instability if the voltage drop inside the nozzle is high enough. Experiments to check the proposed mechanism are suggested.

  10. Parametric Study on Arc Behavior of Magnetically Diffused Arc

    Science.gov (United States)

    Chen, Tang; Li, Hui; Bai, Bing; Liao, Mengran; Xia, Weidong

    2016-01-01

    A model coupling the plasma with a cathode body is applied in the simulation of the diffuse state of a magnetically rotating arc. Four parametric studies are performed: on the external axial magnetic field (AMF), on the cathode shape, on the total current and on the inlet gas velocity. The numerical results show that: the cathode attachment focuses in the center of the cathode tip with zero AMF and gradually shifts off the axis with the increase of AMF; a larger cathode conical angle corresponds to a cathode arc attachment farther away off axis; the maximum values of plasma temperature increase with the total current; the plasma column in front of the cathode tip expands more severely in the axial direction, with a higher inlet speed; the cathode arc attachment shrinks towards the tip as the inlet speed increases. The various results are supposed to be explained by the joint effect of coupled cathode surface heating and plasma rotating flow. supported by National Natural Science Foundation of China (Nos. 11475174, 11035005 and 50876101)

  11. Types of Heart Failure

    Science.gov (United States)

    ... failure. Drug treatments are different for the two types. Systolic failure: The left ventricle loses its ability to contract normally. The heart can't pump with enough force to push enough blood into circulation. Diastolic failure ( ...

  12. Pure Autonomic Failure

    Science.gov (United States)

    ... Drugs GARD Information Navigator FAQs About Rare Diseases Pure autonomic failure Title Other Names: Bradbury Eggleston syndrome; ... Categories: Nervous System Diseases ; RDCRN Summary Summary Listen Pure autonomic failure is characterized by generalized autonomic failure ...

  13. Kidney (Renal) Failure

    Science.gov (United States)

    ... How is kidney failure treated? What is kidney (renal) failure? The kidneys are designed to maintain proper fluid ... marrow and strengthen the bones. The term kidney (renal) failure describes a situation in which the kidneys have ...

  14. Heart failure - medicines

    Science.gov (United States)

    CHF - medicines; Congestive heart failure - medicines; Cardiomyopathy - medicines; HF - medicines ... You will need to take most of your heart failure medicines every day. Some medicines are taken ...

  15. Models of plasma arc welding

    International Nuclear Information System (INIS)

    A complex model of energy transfer from ionized gas through a weld-pool to a heat affected zone (HAZ) is considered here. The model consists of three sub-models: a model of the arc column with skin layers - sheaths coating electrodes, a model of liquid metal flow in a weld-pool, and a model of coupled thermo-mechanical-metallurgical processes in HAZ. These sub-models are descried in three reports. The first report is devoted to a short review of welding plasma models based mostly on the Magneto-Hydro-Dynamics (MHD) theory successfully applied to the simulation of welding process. This report is illustrated by arc models for TIG and PAW welding. The description of thermal energy transfer between three sub-regions of the complex welding domain refers to a large number of processes observed in gaseous electronics, thermodynamics of reacting gases, electro-dynamics of fluid, micro-metallurgy. (author)

  16. Zircon Recycling in Arc Intrusions

    Science.gov (United States)

    Miller, J.; Barth, A.; Matzel, J.; Wooden, J.; Burgess, S.

    2008-12-01

    Recycling of zircon has been well established in arc intrusions and arc volcanoes, but a better understanding of where and how zircons are recycled can help illuminate how arc magma systems are constructed. To that end, we are conducting age, trace element (including Ti-in-zircon temperatures; TzrnTi) and isotopic studies of zircons from the Late Cretaceous (95-85 Ma) Tuolumne Intrusive Suite (TIS) in the Sierra Nevada Batholith (CA). Within the TIS zircons inherited from ancient basement sources and/or distinctly older host rocks are uncommon, but recycled zircon antecrysts from earlier periods of TIS-related magmatism are common and conspicuous in the inner and two most voluminous units of the TIS, the Half Dome and Cathedral Peak Granodiorites. All TIS units have low bulk Zr ([Zr]825°C), [Zr] in the TIS is a factor of 2 to 3 lower than saturation values. Low [Zr] in TIS rocks might be attributed to a very limited supply of zircon in the source, by disequilibrium melting and rapid melt extraction [1], by melting reactions involving formation of other phases that can incorporate appreciable Zr [2], or by removal of zircon at an earlier stage of magma evolution. Based on a preliminary compilation of literature data, low [Zr] is common to Late Cretaceous N.A. Cordilleran granodioritic/tonalitic intrusions (typically Tzrnsat [3]. A corollary is that slightly older zircon antecrysts that are common in the inner units of the TIS could be considered inherited if they are derived from remelting of slightly older intrusions. Remelting at such low temperatures in the arc would require a source of external water. Refs: [1] Sawyer, J.Pet 32:701-738; [2] Fraser et al, Geology 25:607-610; [3] Harrison et al, Geology 35:635- 638

  17. Minor arcs for Goldbach's problem

    CERN Document Server

    Helfgott, H A

    2012-01-01

    The ternary Goldbach conjecture states that every odd number $n\\geq 7$ is the sum of three primes. The estimation of sums of the form $\\sum_{p\\leq x} e(\\alpha p)$, $\\alpha = a/q + O(1/q^2)$, has been a central part of the main approach to the conjecture since (Vinogradov, 1937). Previous work required $q$ or $x$ to be too large to make a proof of the conjecture for all $n$ feasible. The present paper gives new bounds on minor arcs and the tails of major arcs. For $q\\geq 4\\cdot 10^6$, these bounds are of the strength needed to solve the ternary Goldbach conjecture. Only the range $q\\in \\lbrack 10^5, 4\\cdot 10^6\\rbrack$ remains to be checked, possibly by brute force, before the conjecture is proven for all $n$. The new bounds are due to several qualitative improvements. In particular, this paper presents a general method for reducing the cost of Vaughan's identity, as well as a way to exploit the tails of minor arcs in the context of the large sieve.

  18. Electron arc irradiation of the postmastectomy chest wall: clinical results

    International Nuclear Information System (INIS)

    Purpose/Objective: Since 1980 electron arc irradiation of the postmastectomy chest wall has been the preferred technique for patients with advanced breast cancer at the our institution. Here we report the results of this technique in 150 consecutive patients from 1980 to 1994. Materials and Methods: Thoracic computerized tomography was used to determine internal mammary lymph node depth and chest wall thickness, and for computerized dosimetry calculations in all patients. Total doses of 45-50 Gy in 5 to 5 (1(2)) weeks were delivered to the chest wall and internal mammary lymph nodes via electron arc and, in most cases, supraclavicular and axillary nodes were treated with a matching photon field. Patients were assessed for acute and late radiation changes, local and distant control of disease, and survival. The 10 most recently treated patients were censored for disease progression, survival, and late effects calculations, thus giving a mean follow up of 49 months and a median of 33 months. All patients had advanced disease: T stages 1, 2, 3, and 4 represented 21%, 39%, 21% and 19% of the study population, with a mean number of positive axillary lymph nodes of 6.5 (0-29). Analysis was performed according to adjuvant status (no residual disease, n = 90), residual disease (positive margin, n = 15, and primary radiation, n = 2), or recurrent disease (n = 33). Results: Acute radiation reactions were generally mild and self limiting. 27% of patients developed moist desquamation, and 32% had brisk erythema. Actuarial 5 year local control, freedom from distant failure and overall survival was 91%, 64%, and 67% in the adjuvant group; 84%, 50%, and 53% in the residual disease group; and 63%, 34%, and 30% in the recurrent disease group, respectively. In univariate cox regressions, the number of positive lymph nodes was predictive for local failure in the adjuvant group (p<0.037). Chronic complications were minimal with 10% of patients having arm edema, 15% hyperpigmentation

  19. Electron arc irradiation of the postmastectomy chest wall: clinical results

    International Nuclear Information System (INIS)

    Background and purpose: Since 1980 electron arc irradiation of the postmastectomy chest wall has been the preferred technique for patients with advanced breast cancer at our institution. Here we report the results of this technique in 140 consecutive patients treated from 1980 to 1993. Materials and Methods: Thoracic computerized tomography was used to determine internal mammary lymph node depth and chest wall thickness, and for computerized dosimetry calculations. Total doses of 45-50 Gy in 5 to 5 (1(2)) weeks were delivered to the chest wall and internal mammary lymph nodes via electron arc and, in most cases, supraclavicular and axillary nodes were treated with a matching photon field. Patients were assessed for acute and late radiation changes, local and distant control of disease, and survival. Patients had a minimum follow-up of 1 year after completion of radiation treatment, and a mean follow up interval of 49 months and a median of 33 months. All patients had advanced disease: T stages 1, 2, 3, and 4 represented 21%, 39%, 21% and 19% of the study population, with a mean number of positive axillary lymph nodes of 6.5 (range, 0-29). Analysis was performed according to adjuvant status (no residual disease, n=90), residual disease (positive margin, n=15, and primary radiation, n=2), or recurrent disease (n=33). Results: Acute radiation reactions were generally mild and self limiting. A total of 26% of patients developed moist desquamation, and 32% had brisk erythema. Actuarial 5 year local-regional control, freedom from distant failure, and cause-specific survival was 91%, 64%, and 75% in the adjuvant group; 84%, 50%, and 53% in the residual disease group; and 63%, 34%, and 32% in the recurrent disease group, respectively. In univariate Cox regressions, the number of positive lymph nodes was predictive for local failure in the adjuvant group (P=0.037). Chronic complications were minimal with 11% of patients having arm edema, 17% hyperpigmentation, and 13

  20. Electrical and thermal finite element modeling of arc faults in photovoltaic bypass diodes.

    Energy Technology Data Exchange (ETDEWEB)

    Bower, Ward Isaac; Quintana, Michael A.; Johnson, Jay

    2012-01-01

    Arc faults in photovoltaic (PV) modules have caused multiple rooftop fires. The arc generates a high-temperature plasma that ignites surrounding materials and subsequently spreads the fire to the building structure. While there are many possible locations in PV systems and PV modules where arcs could initiate, bypass diodes have been suspected of triggering arc faults in some modules. In order to understand the electrical and thermal phenomena associated with these events, a finite element model of a busbar and diode was created. Thermoelectrical simulations found Joule and internal diode heating from normal operation would not normally cause bypass diode or solder failures. However, if corrosion increased the contact resistance in the solder connection between the busbar and the diode leads, enough voltage potentially would be established to arc across micron-scale electrode gaps. Lastly, an analytical arc radiation model based on observed data was employed to predicted polymer ignition times. The model predicted polymer materials in the adjacent area of the diode and junction box ignite in less than 0.1 seconds.

  1. Protection of Cardiomyocytes from Ischemic/Hypoxic Cell Death via Drbp1 and pMe2GlyDH in Cardio-specific ARC Transgenic Mice*

    Science.gov (United States)

    Pyo, Jong-Ok; Nah, Jihoon; Kim, Hyo-Jin; Chang, Jae-Woong; Song, Young-Wha; Yang, Dong-Kwon; Jo, Dong-Gyu; Kim, Hyung-Ryong; Chae, Han-Jung; Chae, Soo-Wan; Hwang, Seung-Yong; Kim, Seung-Jun; Kim, Hyo-Joon; Cho, Chunghee; Oh, Chang-Gyu; Park, Woo Jin; Jung, Yong-Keun

    2008-01-01

    The ischemic death of cardiomyocytes is associated in heart disease and heart failure. However, the molecular mechanism underlying ischemic cell death is not well defined. To examine the function of apoptosis repressor with a caspase recruitment domain (ARC) in the ischemic/hypoxic damage of cardiomyocytes, we generated cardio-specific ARC transgenic mice using a mouse α-myosin heavy chain promoter. Compared with the control, the hearts of ARC transgenic mice showed a 3-fold overexpression of ARC. Langendoff preparation showed that the hearts isolated from ARC transgenic mice exhibited improved recovery of contractile performance during reperfusion. The cardiomyocytes cultured from neonatal ARC transgenic mice were significantly resistant to hypoxic cell death. Furthermore, the ARC C-terminal calcium-binding domain was as potent to protect cardiomyocytes from hypoxic cell death as ARC. Genome-wide RNA expression profiling uncovered a list of genes whose expression was changed (>2-fold) in ARC transgenic mice. Among them, expressional regulation of developmentally regulated RNA-binding protein 1 (Drbp1) or the dimethylglycine dehydrogenase precursor (pMe2GlyDH) affected hypoxic death of cardiomyocytes. These results suggest that ARC may protect cardiomyocytes from hypoxic cell death by regulating its downstream, Drbp1 and pMe2GlyDH, shedding new insights into the protection of heart from hypoxic damages. PMID:18782777

  2. ARC length control for plasma welding

    Science.gov (United States)

    Iceland, William F. (Inventor)

    1988-01-01

    A control system to be used with a plasma arc welding apparatus is disclosed. The plasma arc welding apparatus includes a plasma arc power supply, a contactor, and an electrode assembly for moving the electrode relative to a work piece. The electrode assembly is raised or lowered by a drive motor. The present apparatus includes a plasma arc adapter connected across the power supply to measure the voltage across the plasma arc. The plasma arc adapter forms a dc output signal input to a differential amplifier. A second input is defined by an adjustable resistor connected to a dc voltage supply to permit operator control. The differential amplifier forms an output difference signal provided to an adder circuit. The adder circuit then connects with a power amplifier which forms the driving signal for the motor. In addition, the motor connects to a tachometor which forms a feedback signal delivered to the adder to provide damping, therby avoiding servo loop overshoot.

  3. On the formation of auroral arcs

    International Nuclear Information System (INIS)

    A new mechanism for auroral arc formation is presented. The characteristic linear shape of auroral arcs is determined by magnetically connected plasma clouds in the distant equatorial magnetosphere. These clouds originate as high speed plasma beams in the magnetotail and in the solar wind. It is found that the free energy for driving an auroral arc is provided by the difference of pressure between the cloud and the ambient plasma. (author)

  4. Programming ArcGIS with Python cookbook

    CERN Document Server

    Pimpler, Eric

    2015-01-01

    Programming ArcGIS with Python Cookbook, Second Edition, is written for GIS professionals who wish to revolutionize their ArcGIS workflow with Python. Whether you are new to ArcGIS or a seasoned professional, you almost certainly spend time each day performing various geoprocessing tasks. This book will teach you how to use the Python programming language to automate these geoprocessing tasks and make you a more efficient and effective GIS professional.

  5. FASTER MUSE CSP ARC CONSISTENCY ALGORITHMS

    OpenAIRE

    Harper, Mary P.; White, Christopher M.; Helzerman, Randall A.; Hockema, Stephen A.

    1997-01-01

    MUSE CSP (Multiply SEgmented Constraint Satisfaction Problem) [5, 61 is an extension to the constraint satisfaction problem (CSP) which is especially useful for problems that segment into riultiple instances of CSP that share variables. In Belzerman and Harper [6], the concepts of MUSE node, arc, and path consistency were defined and algorithms for MUSE arc consistency, MUSE AC-1, and MUSE path consistency were developed. MUSE AC-1 is similar to the CSP arc consistency algorithm AC-4 [ l j ] ...

  6. Effect of Gravity on Arc Shape in GTA Welding-for Low Electric Arc Current

    Institute of Scientific and Technical Information of China (English)

    Hidetoshi FUJII; Yosuke SUMI; Manabu TANAKA; Kiyoshi NOGI

    2003-01-01

    Gas tungsten arc (GTA) welding was performed both in a microgravity environment and in a terrestrial environment,and the arc shapes in both environments were compared. A microgravity condition was obtained using the free fallsystem at the Japan Microgravi

  7. Diffuse and spot mode of cathode arc attachments in an atmospheric magnetically rotating argon arc

    International Nuclear Information System (INIS)

    A model including the cathode, near-cathode region, and arc column was constructed. Specifically, a thermal perturbation layer at the arc fringe was calculated in order to couple sheath/presheath modelling with typical arc column modelling. Comparative investigation of two modes of attachment of a dc (100, 150, 200 A) atmospheric-pressure arc in argon to a thermionic cathode made of pure tungsten was conducted. Computational data revealed that there exists two modes of arc discharge: the spot mode, which has an obvious cathode surface temperature peak in the arc attachment centre; and the diffuse mode, which has a flat cathode surface temperature distribution and a larger arc attachment area. The modelling results of the arc attachment agree with previous experimental observations for the diffuse mode. A further 3D simulation is obviously needed to investigate the non-axisymmetrical features, especially for the spot mode. (paper)

  8. Major arcs for Goldbach's problem

    OpenAIRE

    Helfgott, H. A.

    2013-01-01

    The ternary Goldbach conjecture states that every odd number $n\\geq 7$ is the sum of three primes. The estimation of the Fourier series $\\sum_{p\\leq x} e(\\alpha p)$ and related sums has been central to the study of the problem since Hardy and Littlewood (1923). Here we show how to estimate such Fourier series for $\\alpha$ in the so-called major arcs, i.e., for $\\alpha$ close to a rational of small denominator. This is part of the author's proof of the ternary Goldbach conjecture. In contrast ...

  9. Metals purification by improved vacuum arc remelting

    Science.gov (United States)

    Zanner, Frank J.; Williamson, Rodney L.; Smith, Mark F.

    1994-12-13

    The invention relates to improved apparatuses and methods for remelting metal alloys in furnaces, particularly consumable electrode vacuum arc furnaces. Excited reactive gas is injected into a stationary furnace arc zone, thus accelerating the reduction reactions which purify the metal being melted. Additionally, a cooled condensation surface is disposed within the furnace to reduce the partial pressure of water in the furnace, which also fosters the reduction reactions which result in a purer produced ingot. Methods and means are provided for maintaining the stationary arc zone, thereby reducing the opportunity for contaminants evaporated from the arc zone to be reintroduced into the produced ingot.

  10. Electrode Evaporation Effects on Air Arc Behavior

    Institute of Scientific and Technical Information of China (English)

    LI Xingwen; CHEN Degui; LI Rui; WU Yi; NIU Chunping

    2008-01-01

    A numerical study of the effects of copper and silver vapours on the air arc behavior is performed. The commercial software FLUENT is adapted and modified to develop a two-dimensional magneto-hydrodynamic (MHD) models of arc with the thermodynamic properties and transport coefficients, net emission coefficient for the radiation model of 99% ai-1% Cu, 99% air-1% Ag, and pure air, respectively. The simulation result demonstrates that vaporization of the electrode material may cool the arc center region and reduce the arc velocity. The effects of Ag vapour are stronger compared to those of Cu vapour.

  11. The Abundance of Large Arcs From CLASH

    Science.gov (United States)

    Xu, Bingxiao; Postman, Marc; Meneghetti, Massimo; Coe, Dan A.; Clash Team

    2015-01-01

    We have developed an automated arc-finding algorithm to perform a rigorous comparison of the observed and simulated abundance of large lensed background galaxies (a.k.a arcs). We use images from the CLASH program to derive our observed arc abundance. Simulated CLASH images are created by performing ray tracing through mock clusters generated by the N-body simulation calibrated tool -- MOKA, and N-body/hydrodynamic simulations -- MUSIC, over the same mass and redshift range as the CLASH X-ray selected sample. We derive a lensing efficiency of 15 ± 3 arcs per cluster for the X-ray selected CLASH sample and 4 ± 2 arcs per cluster for the simulated sample. The marginally significant difference (3.0 σ) between the results for the observations and the simulations can be explained by the systematically smaller area with magnification larger than 3 (by a factor of ˜4) in both MOKA and MUSIC mass models relative to those derived from the CLASH data. Accounting for this difference brings the observed and simulated arc statistics into full agreement. We find that the source redshift distribution does not have big impact on the arc abundance but the arc abundance is very sensitive to the concentration of the dark matter halos. Our results suggest that the solution to the "arc statistics problem" lies primarily in matching the cluster dark matter distribution.

  12. Performance tracking under ARCS contracts. Directive

    International Nuclear Information System (INIS)

    The directive discusses the development of a non-resource intensive method for reporting performance based work allocation results under the ARCS (Alternative Remedial Contracting Strategy) contractors

  13. Generalized hyperfocused arcs in $PG(2,p)$

    OpenAIRE

    Blokhuis, A Aart; Marino, G.; Mazzocca, F.

    2013-01-01

    A {\\em generalized hyperfocused arc} $\\mathcal H $ in $PG(2,q)$ is an arc of size $k$ with the property that the $k(k-1)/2$ secants can be blocked by a set of $k-1$ points not belonging to the arc. We show that if $q$ is a prime and $\\mathcal H$ is a generalized hyperfocused arc of size $k$, then $k=1,2$ or 4. Interestingly, this problem is also related to the (strong) cylinder conjecture [Ball S.: The polynomial method in Galois geometries, in Current research topics in Galois geometry, Chap...

  14. Micro-arcing and arc erosion minimization using a DC hybrid switching device

    OpenAIRE

    Swingler, J.; McBride, J. W.

    2008-01-01

    Hybrid switching devices utilize the advantages of both conventional electrical contacts and solid state electronics to minimize arcing during opening and closing operations. This can result in higher reliability and reduces the need for high cost specialist contact materials. The hybrid switch does not eliminate arcing completely, due to the inductive nature of circuits; micro-arcing is known to occur. An experimental dc hybrid switching device is introduced which minimizes arcing for 42 ...

  15. On Possible Arc Inception on Low Voltage Solar Array

    Science.gov (United States)

    Vayner, Boris

    2015-01-01

    Recent analysis of spacecraft failures during the period of 1990-2013 demonstrated clearly that electrostatic discharges caused more than 8 percent of all registered failures and anomalies, and comprised the most costly losses (25 percent) for operating companies and agencies. The electrostatic discharges on spacecraft surfaces are the results of differential charging above some critical (threshold) voltages. The mechanisms of differential charging are well known, and various methods have been developed to prevent a generation of significant electric fields in areas of triple junctions. For example, low bus voltages in Low Earth Orbit plasma environment and slightly conducting layer over cover-glass (ITO) in Geosynchronous Orbit surroundings are believed to be quite reliable measures to prevent discharges on respective surfaces. In most cases, the vulnerable elements of spacecraft (solar arrays, diode boards, etc.) go through comprehensive ground tests in vacuum chambers. However, tests articles contain the miniscule fragments of spacecraft components such as 10-30 solar cells of many thousands deployed on spacecraft in orbit. This is one reason why manufacturing defects may not be revealed in ground tests but expose themselves in arcing on array surface in space. The other reason for ineffectiveness of discharge preventive measures is aging of all materials in harsh orbital environments. The expected life time of modern spacecraft varies within the range of five-fifteen years, and thermal cycling, radiation damages, and mechanical stresses can result in surface erosion on conductive layers and microscopic cracks in cover-glass sheets and adhesive films. These possible damages may cause significant increases in local electric field strengths and subsequent discharges. The primary discharges may or may not be detrimental to spacecraft operation, but they can produce the necessary conditions for sustained arcs initiation. Multiple measures were developed to prevent

  16. The structure and singularities of arc complexes

    DEFF Research Database (Denmark)

    Penner, Robert

    A classical combinatorial fact is that the simplicial complex consisting of disjointly embedded chords in a convex planar polygon is a sphere. For any surface F with non-empty boundary, there is an analogous complex Arc(F) consisting of suitable equivalence classes of arcs in F connecting its bou...

  17. Risk assessment of metal vapor arcing

    Science.gov (United States)

    Hill, Monika C. (Inventor); Leidecker, Henning W. (Inventor)

    2009-01-01

    A method for assessing metal vapor arcing risk for a component is provided. The method comprises acquiring a current variable value associated with an operation of the component; comparing the current variable value with a threshold value for the variable; evaluating compared variable data to determine the metal vapor arcing risk in the component; and generating a risk assessment status for the component.

  18. Implementing RapidArc into clinical routine

    DEFF Research Database (Denmark)

    Van Esch, Ann; Huyskens, Dominique P; Behrens, Claus F;

    2011-01-01

    With the increased commercial availability of intensity modulated arc therapy (IMAT) comes the need for comprehensive QA programs, covering the different aspects of this newly available technology. This manuscript proposes such a program for the RapidArc (RA) (Varian Medical Systems, Palo Alto) I...

  19. Characterization of Micro-arc Oxidized Titanium

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The observation of the sparkling discharges during the micro-arc oxidation process in KOH aqueous electrolyte was achieved. The change of surface morphology was progressively observed and a plausible pore formation mechanism is proposed. Cell proliferation and ALP activity of micro-arc oxidized titanium was evaluated by human body derived osteoblasts and slightly better than those of blasted surface.

  20. Real System Failures

    Data.gov (United States)

    National Aeronautics and Space Administration — This resource area contains descriptions of actual electronic systems failure scenarios with an emphasis on the diversity of failure modes and effects that can...

  1. What Causes Respiratory Failure?

    Science.gov (United States)

    ... page from the NHLBI on Twitter. What Causes Respiratory Failure? Diseases and conditions that impair breathing can cause ... injure your lungs. Normal Lungs and Conditions Causing Respiratory Failure Figure A shows the location of the lungs, ...

  2. Acute liver failure

    DEFF Research Database (Denmark)

    Larsen, Fin Stolze; Bjerring, Peter Nissen

    2011-01-01

    Acute liver failure (ALF) results in a multitude of serious complications that often lead to multi-organ failure. This brief review focuses on the pathophysiological processes in ALF and how to manage these.......Acute liver failure (ALF) results in a multitude of serious complications that often lead to multi-organ failure. This brief review focuses on the pathophysiological processes in ALF and how to manage these....

  3. Numerical Study on Arc Plasma Behavior During Arc Commutation Process in Direct Current Circuit Breaker

    International Nuclear Information System (INIS)

    This paper focuses on the numerical investigation of arc plasma behavior during arc commutation process in a medium-voltage direct current circuit breaker (DCCB) contact system. A three-dimensional magneto-hydrodynamic (MHD) model of air arc plasma in the contact system of a DCCB is developed, based on commercial software FLUENT. Coupled electromagnetic and gas dynamic interactions are considered as usual, and a thin layer of nonlinear electrical resistance elements is used to represent the voltage drop of plasma sheath and the formation of new arc root. The distributions of pressure, temperature, gas flow and current density of arc plasma in arc region are calculated. The simulation results indicate that the pressure distribution related to the contact system has a strong effect on the arc commutation process, arising from the change of electrical conductivity in the arc root region. In DCCB contact system, the pressure of arc root region will be concentrated and higher if the space above the moving contact is enclosed, which is not good for arc root commutation. However, when the region is opened, the pressure distribution would be lower and more evenly, which is favorable for the arc root commutation.

  4. Arc flash hazard analysis and mitigation

    CERN Document Server

    Das, J C

    2012-01-01

    "All the aspects of arc flash hazard calculations and their mitigation have been covered. Knowledge of electrical power systems up to undergraduate level is assumed. The calculations of short-circuits, protective relaying and varied electrical system configurations in industrial power systems are addressed. Protection systems address differential relays, arc flash sensing relays, protective relaying coordination, current transformer operation and saturation and applications to major electrical equipments from the arc flash considerations. Current technologies and strategies for arc flash mitigation have been covered. A new algorithm for the calculation of arc flash hazard accounting for the decaying nature of the short-circuit currents is included. There are many practical examples and study cases. Review questions and references follow each chapter"--

  5. Sensor Control of Robot Arc Welding

    Science.gov (United States)

    Sias, F. R., Jr.

    1983-01-01

    The potential for using computer vision as sensory feedback for robot gas-tungsten arc welding is investigated. The basic parameters that must be controlled while directing the movement of an arc welding torch are defined. The actions of a human welder are examined to aid in determining the sensory information that would permit a robot to make reproducible high strength welds. Special constraints imposed by both robot hardware and software are considered. Several sensory modalities that would potentially improve weld quality are examined. Special emphasis is directed to the use of computer vision for controlling gas-tungsten arc welding. Vendors of available automated seam tracking arc welding systems and of computer vision systems are surveyed. An assessment is made of the state of the art and the problems that must be solved in order to apply computer vision to robot controlled arc welding on the Space Shuttle Main Engine.

  6. In Support of Failure

    Science.gov (United States)

    Carr, Allison

    2013-01-01

    In this essay, I propose a concerted effort to begin devising a theory and pedagogy of failure. I review the discourse of failure in Western culture as well as in composition pedagogy, ultimately suggesting that failure is not simply a judgement or indication of rank but is a relational, affect-bearing concept with tremendous relevance to…

  7. Recurrent acute renal failure

    OpenAIRE

    Satish, S.; Rajesh, R.; Kurian, G.; Seethalekshmi, N. V.; Unni, M.; Unni, V. N.

    2010-01-01

    While acute renal failure secondary to intravascular hemolysis is well described in hemolytic anemias, recurrent acute renal failure as the presenting manifestation of a hemolytic anemia is rare. We report a patient with recurrent acute renal failure who was found to have paroxysmal nocturnal hemoglobinuria (PNH), on evaluation.

  8. Role of arc mode in laser-metal active gas arc hybrid welding of mild steel

    International Nuclear Information System (INIS)

    Highlights: • Pulsed arc is more effective to improve the stability of laser-arc hybrid welding. • LCHW has the highest fraction of acicular ferrite and high-angle grain boundaries. • Grain refinement depends on effective current of the arc. • LSHW has the most apparent vestige of texture components. • The microstructure and microtexture formation mechanisms were summarized. - Abstract: Arc mode plays an important role in joint characterizations of arc welding, but it has been seldom considered in laser-arc hybrid welding. This paper investigated the role of arc mode on laser-metal active gas (MAG) arc hybrid welding of mild steel. Three arc modes were employed, which were cold metal transfer (CMT), pulsed spray arc and standard short circuiting arc. Microtexture of the joints were observed and measured via electron back scattering diffraction (EBSD) system to reveal the effect of arc mode on microstructure. Mechanical properties of the joints were evaluated by tensile and Charpy V-notch impact tests. It was found that both the stability and mechanical properties of laser-CMT hybrid welding (LCHW) is the best, while those of laser-standard short circuiting arc welding (LSHW) is the worst. OM and EBSD results showed that the fraction of acicular ferrite and high-angle grain boundaries in fusion zone decreases gradually in the sequence of LCHW, laser-pulsed spray arc welding and LSHW, while the mean grain size increases gradually. Finally, the microstructure formation mechanisms and the relationship between microstructure and mechanical properties were summarized by the loss of alloying element and the stirring effect in molten pool

  9. INTERPOLATION WITH RESTRICTED ARC LENGTH

    Institute of Scientific and Technical Information of China (English)

    Petar Petrov

    2003-01-01

    For given data (ti,yi), I= 0,1,…,n,0 = t0 <t1 <…<tn = 1we study constrained interpolation problem of Favard type inf{‖f"‖∞|f∈W2∞[0,1],f(ti)=yi,i=0,…,n,l(f;[0,1])≤l0}, wherel(f";[0,1])=∫1 0 / 1+f'2(x)dx is the arc length off in [0,1]. We prove the existence of a solution f* of the above problem, that is a quadratic spline with a second derivative f"* , which coincides with one of the constants - ‖f"*‖∞,0,‖f"*‖∞ between every two consecutive knots. Thus, we extend a result ofKarlin concerning Favard problem, to the case of restricted length interpolation.

  10. Computer simulation to arc spraying

    Institute of Scientific and Technical Information of China (English)

    梁志芳; 李午申; 王迎娜

    2004-01-01

    The arc spraying process is divided into two stages: the first stage is atomization-spraying stream (ASS) and the second one is spraying deposition (SD). Then study status is described of both stages' physical model and corresponding controlling-equation. Based on the analysis of study status, the conclusion as follows is got. The heat and mass transfer models with two or three dimensions in ASS stage should be established to far deeply analyses the dynamical and thermal behavior of the overheat droplet. The statistics law of overheated droplets should be further studied by connecting simulation with experiments. More proper validation experiments should be designed for flattening simulation to modify the models in SD stage.

  11. On the use of accelerators dosimetric ally equivalent to the technique RapidArc VMAT

    International Nuclear Information System (INIS)

    Scheduled maintenance and unexpected failures can cause a stop in the operation of accelerators for hours or days. Prolonging treatments cause discomfort, anxiety and decreased chance for cure. Using a second accelerator backup set of the same design and dosimetry, would mitigate the effects of such interruptions. The aim of this study is to determine the safety of using either two accelerators in Rapid Arc VMAT treatments. (Author)

  12. Evaluation of the clinical usefulness of modulated Arc treatment

    OpenAIRE

    Lee, Young Kyu; Jang, Hong Seok; Kim, Yeon Sil; Choi, Byung Ock; Nam, Sang Hee; Park, Hyeong Wook; Kim, Shin Wook; Shin, Hun Joo; Lee, Jae Choon; Kim, Ji Na; PARK, SUNG KWANG; Kim, Jin Young; Kang, Young-Nam

    2015-01-01

    The purpose of this study is to evaluate the clinical usefulness of modulated arc (mARC) treatment techniques. The mARC treatment plans of the non-small cell lung cancer (NSCLC) patients were performed in order to verify the clinical usefulness of mARC. A pre study was conducted to find the most competent plan condition of mARC treatment and the usefulness of mARC treatment plan was evaluated by comparing it with the other Arc treatment plans such as Tomotherapy and RapidArc. In the case of m...

  13. Propagation of back-arc extension into the arc lithosphere in the southern New Hebrides volcanic arc

    Science.gov (United States)

    Patriat, M.; Collot, J.; Danyushevsky, L.; Fabre, M.; Meffre, S.; Falloon, T.; Rouillard, P.; Pelletier, B.; Roach, M.; Fournier, M.

    2015-09-01

    New geophysical data acquired during three expeditions of the R/V Southern Surveyor in the southern part of the North Fiji Basin allow us to characterize the deformation of the upper plate at the southern termination of the New Hebrides subduction zone, where it bends eastward along the Hunter Ridge. Unlike the northern end of the Tonga subduction zone, on the other side of the North Fiji Basin, the 90° bend does not correspond to the transition from a subduction zone to a transform fault, but it is due to the progressive retreat of the New Hebrides trench. The subduction trench retreat is accommodated in the upper plate by the migration toward the southwest of the New Hebrides arc and toward the south of the Hunter Ridge, so that the direction of convergence remains everywhere orthogonal to the trench. In the back-arc domain, the active deformation is characterized by propagation of the back-arc spreading ridge into the Hunter volcanic arc. The N-S spreading axis propagates southward and penetrates in the arc, where it connects to a sinistral strike-slip zone via an oblique rift. The collision of the Loyalty Ridge with the New Hebrides arc, less than two million years ago, likely initiated this deformation pattern and the fragmentation of the upper plate. In this particular geodynamic setting, with an oceanic lithosphere subducting beneath a highly sheared volcanic arc, a wide range of primitive subduction-related magmas has been produced including adakites, island arc tholeiites, back-arc basin basalts, and medium-K subduction-related lavas.

  14. Method of plasma-arc welding and properties of welded joints of the 12Kh18N10T steel tubes

    International Nuclear Information System (INIS)

    The aim of the work was to improve the plasma-arc welding of 12Kh18N10T steel pipes for service at temperatures up to 350 deg C under cyclic loading. The quality of welds was checked by metallographic means and by tests for tensile and impact strengths, small-cycle fatigue and hardness. A method was developed for plasma-arc welding of pivoting pipe joints with wall thicknesses of 6-10 mm in a single pass without bevelling of edges and without additive. Welds made by the above procedure possess a higher resistance to failure as compared to manual electric-arc welds

  15. Waste form development for a DC arc furnace

    International Nuclear Information System (INIS)

    A laboratory crucible study was conducted to develop waste forms to treat nonradioactive simulated 238Pu heterogeneous debris waste from Savannah River, metal waste from the Idaho National Engineering Laboratory (INEL), and nominal waste also from INEL using DC arc melting. The preliminary results showed that the different waste form compositions had vastly different responses for each processing effect. The reducing condition of DC arc melting had no significant effects on the durability of some waste forms while it decreased the waste form durability from 300 to 700% for other waste forms, which resulted in the failure of some TCLP tests. The right formulations of waste can benefit from devitrification and showed an increase in durability by 40%. Some formulations showed no devitrification effects while others decreased durability by 200%. Increased waste loading also affected waste form behavior, decreasing durability for one waste, increasing durability by 240% for another, and showing no effect for the third waste. All of these responses to the processing and composition variations were dictated by the fundamental glass chemistry and can be adjusted to achieve maximal waste loading, acceptable durability, and desired processing characteristics if each waste formulation is designed for the result according to the glass chemistry

  16. Plasma Arc Augmented CO2 laser welding

    DEFF Research Database (Denmark)

    Bagger, Claus; Andersen, Mikkel; Frederiksen, Niels;

    2001-01-01

    In order to reduce the hardness of laser beam welded 2.13 mm medium strength steel CMn 250, a plasma arc has been used simultaneously with a 2.6 kW CO2 laser source. In a number of systematic laboratory tests, the plasma arc current, plasma gas flow and distance to the laser source were varied with....... With the addition of a plasma arc, the hardness could overall be reduced to between 200 and 220 HV1, i.e. about 27 percent. In the seam middle, the reduction was 36 percent....

  17. Arc saw and its application to decommissioning

    International Nuclear Information System (INIS)

    The arc saw is a toothless, circular saw that cuts by arc erosion. A model was built to study the arc saw's usefulness in cutting up radioactively contaminated metal scrap. It was chosen because it cuts with very little contact to the work piece and because cutting is not affected by material hardness. After installation of several improvements it was found it could cut almost any combination of metals and that clamping or fixturing requirements were minimum. Cutting proceeds rapidly and efficiently. 10 figures

  18. Nonlinear Study of Industrial Arc Spring Dampers

    DEFF Research Database (Denmark)

    Lahriri, Said; Santos, Ilmar; Hartmann, Henning

    2011-01-01

    for varying the damping characteristics of the SFD as well as the dynamic forces acting on the SFD. Phase plane orbits together with Poincar´e maps are given for different arc spring damping and static and dynamic load cases. Besides, bifurcation diagrams as a function of the arc spring damping and...... forces acting on the SFD are presented. It is worth mentioning, that the maps and diagrams can be used as design guidance. Finally, a comparison between the numerical results and experimental result is facilitated in form of waterfall diagrams. For this, a full scale model of the arc-spring damper was...

  19. Modeling Multi-Arc Spraying Systems

    Science.gov (United States)

    Bobzin, K.; Öte, M.

    2016-06-01

    The use of plasma as energy source in thermal spraying enables among others the processing of feed stock materials with very high melting temperatures as coating materials. New generation multi-arc plasma spraying systems are widely spread and promise several advantages in comparison to the conventional single-arc systems. Numerical modeling of multi-arc plasma spraying offers the possibility to increase the understanding about this process. This study focuses on the numerical modeling of three-cathode spraying systems, introducing the recent activities in this field and discussing the numerical aspects which influence the prediction power of the models.

  20. Formation of the G-ring arc

    Science.gov (United States)

    Araujo, N. C. S.; Vieira Neto, E.; Foryta, D. W.

    2016-05-01

    Since 2004, the images obtained by Cassini spacecraft's on-board cameras have revealed the existence of several small satellites in the Saturn system. Some of these small satellites are embedded in arcs of particles. While these satellites and their arcs are known to be in corotation resonances with Mimas, their origin remains unknown. This work investigates one possible process for capturing bodies into a corotation resonance, which involves raising the eccentricity of a perturbing body. Therefore, through numerical simulations and analytical studies, we show a scenario that the excitation of Mimas' eccentricity could capture particles in a corotation resonance and given a possible explanation for the origin for the arcs.

  1. Arc pressure control in GTA welding

    International Nuclear Information System (INIS)

    Relationships are established between the peak current of a pulsed, rectangular current waveform and the pulse current duty cycle under conditions of constant arc power. By appropriate choice of these interrelated parameters, it is shown that the arc pressure may be varied over a wide range even though the arc power is held constant. The methodology is suggested as a means of countering the effect of gravity in 5-G welding, while maintaining constant heat input to the weld. Combined with appropriate penetration sensors, the methodology is additionally suggested as a means of controlling penetration

  2. Formation of the G-ring arc

    CERN Document Server

    Araujo, N C S; Foryta, D W

    2016-01-01

    Since 2004, the images obtained by Cassini spacecraft's on-board cameras have revealed the existence of several small satellites in the Saturn system. Some of these small satellites are embedded in arcs of particles. While these satellites and their arcs are known to be in corotation resonances with Mimas, their origin remains unknown. This work investigates one possible process for capturing bodies into a corotation resonance, which involves raising the eccentricity of a perturbing body. Therefore, through numerical simulations and analytical studies, we show a scenario that the excitation of Mimas' eccentricity could capture particles in a corotation resonance and given a possible explanation for the origin for the arcs.

  3. Microstructure and mechanical properties of aluminum 5083 weldments by gas tungsten arc and gas metal arc welding

    International Nuclear Information System (INIS)

    Highlights: ► Welding zones by GTAW and GMAW are softer than the parent material Al5083. ► GTAW for Al5083 are mechanically more reliable than that welded by GMAW. ► GTAW welds fail by shear, but GMAW welds show mixed shear and normal failure. - Abstract: The mechanical properties and microstructural features of aluminum 5083 (Al5083) weldments processed by gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW) are investigated. Weldments processed by both methods are mechanically softer than the parent material Al5083, and could be potential sites for plastic localization. It is revealed that Al5083 weldments processed by GTAW are mechanical more reliable than those by GMAW. The former bears higher strength, more ductility, and no apparent microstructure defects. Perceivable porosity in weldments by GMAW is found, which could account for the distinct mechanical properties between weldments processed by GTAW and GMAW. It is suggested that caution should be exercised when using GMAW for Al5083 in the high-speed-train industry where such light weight metal is broadly used.

  4. Numerical investigations of arc behaviour in gas metal arc welding using ANSYS CFX

    Science.gov (United States)

    Schnick, M.; Fuessel, U.; Hertel, M.; Spille-Kohoff, A.; Murphy, A. B.

    2011-06-01

    Current numerical models of gas metal arc welding (GMAW) are trying to combine magnetohydrodynamics (MHD) models of the arc and volume of fluid (VoF) models of metal transfer. They neglect vaporization and assume an argon atmosphere for the arc region, as it is common practice for models of gas tungsten arc welding. These models predict temperatures above 20 000 K and a temperature distribution similar to tungsten inert gas (TIG) arcs. However, current spectroscopic temperature measurements in GMAW arcs demonstrate much lower arc temperatures. In contrast to TIG arcs they found a central local minimum of the radial temperature distribution. The paper presents a GMAW arc model that considers metal vapour and which is in a very good agreement with experimentally observed temperatures. Furthermore, the model is able to predict the local central minimum in the radial temperature and the radial electric current density distributions for the first time. The axially symmetric model of the welding torch, the work piece, the wire and the arc (fluid domain) implements MHD as well as turbulent mixing and thermal demixing of metal vapour in argon. The mass fraction of iron vapour obtained from the simulation shows an accumulation in the arc core and another accumulation on the fringes of the arc at 2000 to 5000 K. The demixing effects lead to very low concentrations of iron between these two regions. Sensitive analyses demonstrate the influence of the transport and radiation properties of metal vapour, and the evaporation rate relative to the wire feed. Finally the model predictions are compared with the measuring results of Zielińska et al.

  5. Prostate treatments, 1MRT o RapidArc; Tratamiento de prostata, IMART o RapidArc?

    Energy Technology Data Exchange (ETDEWEB)

    Castro novais, J.; Ruiz Maqueda, S.; Pardo Perez, E.; Molina Lopez, M. Y.; Cerro Penalver, E.

    2015-07-01

    Techniques that modulate the dose (as IMRT or RapidArcTM) improve dose homogeneity within the target volume decreasing the dose in healthy organs. The aim of this work is to study the dosimetric differences in prostate radiotherapy treatments with IMRT and RapidArcTM. The results of the 109 patients studied show that plans to RapidArcTM have better coverage, compliance and dose gradient outside the target volume. (Author)

  6. Sitka, Alaska 1 arc-second DEM

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Sitka, Alaska Elevation Grid provides bathymetric data in ASCII raster format of 1 arc-second resolution in geographic coordinates. This grid is strictly for...

  7. Sitka, Alaska 3 arc-second DEM

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Sitka, Alaska Elevation Grid provides bathymetric data in ASCII raster format of 3 arc-second resolution in geographic coordinates. This grid is strictly for...

  8. Stretched arc discharge in produced water.

    Science.gov (United States)

    Cho, Y I; Wright, K C; Kim, H S; Cho, D J; Rabinovich, A; Fridman, A

    2015-01-01

    The objective of the present study was to investigate the feasibility of stretching an arc discharge in produced water to increase the volume of produced water treated by plasma. Produced water is the wastewater generated by hydraulic fracturing of shale during the production phase in shale-oil or shale-gas exploration. The electric conductivity of produced water is in the range of 50-200 mS/cm, which provides both a challenge and opportunity for the application of plasmas. Stretching of an arc discharge in produced water was accomplished using a ground electrode and two high-voltage electrodes: one positioned close to the ground electrode and the other positioned farther away from the ground. The benefit of stretching the arc is that the contact between the arc and water is significantly increased, resulting in more efficient plasma treatment in both performance and energy cost. PMID:25638080

  9. Magneto-plasma-dynamic arc thruster

    Science.gov (United States)

    Burkhart, J. A. (Inventor)

    1973-01-01

    The performance of a magnetoplasmadynamic arc thruster, in the 600 to 2,100 seconds specific impulse range, was improved by locating its cathode in the exhaust beam downstream of the anode and main propellant injection point.

  10. Observation of gliding arc surface treatment

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Zhu, Jiajian; Ehn, A.;

    2015-01-01

    . Water contact angle measurements indicate that the treatment uniformity improves significantly when the AC gliding arc is tilted to the polymer surface. Thickness reduction of the gas boundary layer, explaining the improvement of surface treatment, by the ultrasonic irradiation was directly observed for......An alternating current (AC) gliding arc can be conveniently operated at atmospheric pressure and efficiently elongated into the ambient air by an air flow and thus is useful for surface modification. A high speed camera was used to capture dynamics of the AC gliding arc in the presence of polymer...... surfaces. A gap was observed between the polymer surface and the luminous region of the plasma column, indicating the existence of a gas boundary layer. The thickness of the gas boundary layer is smaller at higher gas flow-rates or with ultrasonic irradiation to the AC gliding arc and the polymer surface...

  11. Archival Research Catalog (ARC) Archival Descriptions

    Data.gov (United States)

    National Archives and Records Administration — The Archival Research Catalog (ARC) data set provides archival descriptions of the permanent holdings of the federal government in the custody of the National...

  12. Seward, Alaska 1 arc-second DEM

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 1 arc-second Seward Alaska Elevation Grid provides bathymetric data in ASCII raster format of .89-second resolution in geographic coordinates. This grid is...

  13. Antithrombotics in heart failure.

    OpenAIRE

    Miličić, Davor; Samardžić, Jure; Petričević, Mate

    2014-01-01

    Heart failure is a common clinical condition associated with high morbidity and mortality rate despite significant improvements in pharmacotherapy and implementation of medical procedures. Patients with heart failure are at an increased risk of developing arterial and venous thrombosis, which contribute to the high rate of adverse events and fatal outcomes. Many heart failure patients routinely receive antithrombotic therapy due to the presence of a specific indication...

  14. Lungs in Heart Failure

    OpenAIRE

    Anna Apostolo; Giuliano Giusti; Paola Gargiulo; Maurizio Bussotti; Piergiuseppe Agostoni

    2012-01-01

    Lung function abnormalities both at rest and during exercise are frequently observed in patients with chronic heart failure, also in the absence of respiratory disease. Alterations of respiratory mechanics and of gas exchange capacity are strictly related to heart failure. Severe heart failure patients often show a restrictive respiratory pattern, secondary to heart enlargement and increased lung fluids, and impairment of alveolar-capillary gas diffusion, mainly due to an increased resistance...

  15. 49 CFR 195.226 - Welding: Arc burns.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Welding: Arc burns. 195.226 Section 195.226 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... PIPELINE Construction § 195.226 Welding: Arc burns. (a) Each arc burn must be repaired. (b) An arc burn...

  16. Effect of arc on radiation thermometry in welding process

    Institute of Scientific and Technical Information of China (English)

    李亮玉; 王燕; 武宝林

    2002-01-01

    The effect of arc on radiation thermometry is analyzed in a field close to the arc during the welding process, and the ratio of signal to noise and other factors are obtained for a small current arc .The method of the temperature measurement is feasible when the arc current is decreased to a smaller value in the welding process.

  17. Sensitivity of collapsed arc QA method for delivery errors in Volumetric Modulated Arc Therapy (VMAT)

    International Nuclear Information System (INIS)

    In this paper the sensitivity of an Electronic Portal Imaging Device (EPID) to detecting introduced Volumetric Arc Therapy (VMAT) treatment errors was studied using the Collapsed Arc method. Two clinical Head and Neck (H and N) and Prostate treatment plans had gantry dependent dose and MLC errors introduced to the plans. These plans were then delivered to an Elekta Synergy Linear Accelerator EPID and compared to the original treatment planning system Collapsed Arc dose matrix. With the Collapsed Arc technique the EPID was able to detect MLC errors down to 2mm and dose errors of down to 3% depending on the treatment plan complexity and gamma tolerance used

  18. Spectral characteristics of arc plasma during laser-arc double-sided welding for aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    Kezhao Zhang; Zhenglong Lei; Xianglong Wang; Yanbin Chen; Yaobang Zhao

    2015-01-01

    In laser-arc double-sided welding,the spectral characteristics of the arc plasma are calculated and analyzed by spectroscopic diagnosis.The results show that,compared with conventional tungsten inert gas (TIG) welding,the introduction of a laser changes the physical characteristics of the arc plasma regardless of whether laser plasma penetration takes place,and that the influence of the laser mainly affects the near-anode region of the arc.When the laser power is relatively low,the arc column tends to compress,and the arc spectral characteristics show no significant difference.When the arc root constricts,compared with pure TIG arc,the electron density increases by ~2.7 times and the electron temperature decreases by ~3000 K.When the arc column expands,the intensities of spectral lines of both the metal and Ar atoms are the strongest.But it is also observed that the electron density reduces,whereas there is no obvious decrease of electron temperature.

  19. Heat flow in the Lesser Antilles island arc and adjacent back arc Grenada basin

    OpenAIRE

    Manga, Michael; Hornbach, Matthew J.; Friant, Anne Le; Ishizuka, Osamu; Stroncik, Nicole; Adachi, Tatsuya; Aljahdali, Mohammed; Boudon, Georges; Breitkreuz, Christoph; Fraass, Andrew; Fujinawa, Akihiko; Hatfield, Robert; Jutzeler, Martin; Kataoka, Kyoko; Lafuerza, Sara

    2012-01-01

    Using temperature gradients measured in 10 holes at 6 sites, we generate the first high fidelity heat flow measurements from Integrated Ocean Drilling Program drill holes across the northern and central Lesser Antilles arc and back arc Grenada basin. The implied heat flow, after correcting for bathymetry and sedimentation effects, ranges from about 0.1 W/m2 on the crest of the arc, midway between the volcanic islands of Montserrat and Guadeloupe, to 15 km from the crest in the back arc direct...

  20. Hybrid Laser-Arc Welding Tanks Steels

    Science.gov (United States)

    Turichin, G.; Tsibulskiy, I.; Kuznetsov, M.; Akhmetov, A.; Klimova-Korsmik, O.

    2016-04-01

    The results investigate hybrid laser-arc welding of high strength steels using design responsible metallic construction and the highest strength body of vehicles. Welds from modern high strength steels grade Hardox 400, Hardox 450, Armox 600T and AB were created. High power fiber laser LS-15 with output 15 kW and arc rectifier VDU - 1500 DC were used in the experiment. Results of the metallographic research and mechanical tests are presented.

  1. Overtwisted open books from sobering arcs

    OpenAIRE

    Goodman, Noah

    2004-01-01

    We study open books on three manifolds which are compatible with an overtwisted contact structure. We show that the existence of certain arcs, called sobering arcs, is a sufficient condition for an open book to be overtwisted, and is necessary up to stabilization by positive Hopf-bands. Using these techniques we prove that some open books arising as the boundary of symplectic configurations are overtwisted, answering a question of Gay in Algebr. Geom. Topol. 3 (2003) 569--586.

  2. Metal Vapor Arcing Risk Assessment Tool

    Science.gov (United States)

    Hill, Monika C.; Leidecker, Henning W.

    2010-01-01

    The Tin Whisker Metal Vapor Arcing Risk Assessment Tool has been designed to evaluate the risk of metal vapor arcing and to help facilitate a decision toward a researched risk disposition. Users can evaluate a system without having to open up the hardware. This process allows for investigating components at risk rather than spending time and money analyzing every component. The tool points to a risk level and provides direction for appropriate action and documentation.

  3. Multi-color detection of gravitational arcs

    OpenAIRE

    Maturi, Matteo; Mizera, Sebastian; Seidel, Gregor

    2013-01-01

    Strong gravitational lensing provides fundamental insights into the understanding of the dark matter distribution in massive galaxies, galaxy clusters and the background cosmology. Despite their importance, the number of gravitational arcs discovered so far is small. The urge for more complete, large samples and unbiased methods of selecting candidates is rising. A number of methods for the automatic detection of arcs have been proposed in the literature, but large amounts of spurious detecti...

  4. Electric arc furnace models for flicker study

    Directory of Open Access Journals (Sweden)

    Catalina González Castaño

    2016-06-01

    Full Text Available Objective: The aim of this paper is to evaluate voltage fluctuations or flicker of two electric arc furnace models through comparison with real data.Method: The first proposed model is founded on the energy conservation principle, which generates a non-linear differential equation modelling the electric arc voltage – current characteristics. Voltage fluctuations are generated using a chaotic circuit that modulates the amplitude of arc voltage. The second model is based on the empirical relationship between the arc diameter or length as well as voltage and electrical current on the arc. Voltage fluctuations are considered adding a random signal in the arc length. Both models are implemented in PSCADTM.Results: The results of both models are compared with real data taken at the most critical stage of the operation of the furnace, and they show that the model based on energy conservation has a lower average mean square error in the voltages and currents 5.6 V and 1.7 kA against 27,2 V y 3.38 kA obtained with the second model.Conclusions: Both models consider the nonlinearity and random behavior present in this type of load, validating their inclusion in computer models of electric power systems.

  5. Recent ARC developments: Through modularity to interoperability

    Energy Technology Data Exchange (ETDEWEB)

    Smirnova, O; Cameron, D; Ellert, M; Groenager, M; Johansson, D; Kleist, J [NDGF, Kastruplundsgade 22, DK-2770 Kastrup (Denmark); Dobe, P; Joenemo, J; Konya, B [Lund University, Experimental High Energy Physics, Institute of Physics, Box 118, SE-22100 Lund (Sweden); Fraagaat, T; Konstantinov, A; Nilsen, J K; Saada, F Ould; Qiang, W; Read, A [University of Oslo, Department of Physics, P. O. Box 1048, Blindern, N-0316 Oslo (Norway); Kocan, M [Pavol Jozef Safarik University, Faculty of Science, Jesenna 5, SK-04000 Kosice (Slovakia); Marton, I; Nagy, Zs [NIIF/HUNGARNET, Victor Hugo 18-22, H-1132 Budapest (Hungary); Moeller, S [University of Luebeck, Inst. Of Neuro- and Bioinformatics, Ratzeburger Allee 160, D-23538 Luebeck (Germany); Mohn, B, E-mail: oxana.smirnova@hep.lu.s [Uppsala University, Department of Physics and Astronomy, Div. of Nuclear and Particle Physics, Box 535, SE-75121 Uppsala (Sweden)

    2010-04-01

    The Advanced Resource Connector (ARC) middleware introduced by NorduGrid is one of the basic Grid solutions used by scientists worldwide. While being well-proven in daily use by a wide variety of scientific applications at large-scale infrastructures like the Nordic DataGrid Facility (NDGF) and smaller scale projects, production ARC of today is still largely based on conventional Grid technologies and custom interfaces introduced a decade ago. In order to guarantee sustainability, true cross-system portability and standards-compliance based interoperability, the ARC community undertakes a massive effort of implementing modular Web Service (WS) approach into the middleware. With support from the EU KnowARC project, new components were introduced and the existing key ARC services got extended with WS technology based standard-compliant interfaces following a service-oriented architecture. Such components include the hosting environment framework, the resource-coupled execution service, the re-engineered client library, the self-healing storage solution and the peer-to-peer information system, to name a few. Gradual introduction of these new services and client tools into the production middleware releases is carried out together with NDGF and thus ensures a smooth transition to the next generation Grid middleware. Standard interfaces and modularity of the new component design are essential for ARC contributions to the planned Universal Middleware Distribution of the European Grid Initiative.

  6. Physics of arcs in circuit breakers

    International Nuclear Information System (INIS)

    Some typical examples of circuit breakers are shown. Common to all these devices is that an electric arc is formed when the breaker operates which is responsible for the current interruption. The physics of those arcs can be described by the simplest single-fluid model of plasma physics which differs from the set of gas dynamic equations only by the following three terms: radiative energy transfer magnetic force and Joulean heating. These terms describe typical circuit breaker arc phenomena. This is discussed by means of three examples. The first example treats the influence of the radiative energy transfer on the temperature distribution of high-voltage circuit-breaker arcs. The second example is a discussion of the magnetic stability of circuit breaker arcs and the third example is concerned with the problem of flow turbulence produced at the arc boundary. The last effect is closely related to the current interruption process in high-voltage circuit breakers. A semi-empirical description of the turbulent heat exchange leads to a prediction of the breaking capacity for this type of circuit breaker. (author)

  7. Recent ARC developments: Through modularity to interoperability

    International Nuclear Information System (INIS)

    The Advanced Resource Connector (ARC) middleware introduced by NorduGrid is one of the basic Grid solutions used by scientists worldwide. While being well-proven in daily use by a wide variety of scientific applications at large-scale infrastructures like the Nordic DataGrid Facility (NDGF) and smaller scale projects, production ARC of today is still largely based on conventional Grid technologies and custom interfaces introduced a decade ago. In order to guarantee sustainability, true cross-system portability and standards-compliance based interoperability, the ARC community undertakes a massive effort of implementing modular Web Service (WS) approach into the middleware. With support from the EU KnowARC project, new components were introduced and the existing key ARC services got extended with WS technology based standard-compliant interfaces following a service-oriented architecture. Such components include the hosting environment framework, the resource-coupled execution service, the re-engineered client library, the self-healing storage solution and the peer-to-peer information system, to name a few. Gradual introduction of these new services and client tools into the production middleware releases is carried out together with NDGF and thus ensures a smooth transition to the next generation Grid middleware. Standard interfaces and modularity of the new component design are essential for ARC contributions to the planned Universal Middleware Distribution of the European Grid Initiative.

  8. New method for capturing arc of moving on switching apparatus

    Institute of Scientific and Technical Information of China (English)

    LIU Jiao-min; WANG Jing-hong

    2007-01-01

    The switching arc that occurs in contact gap when contact of low voltage apparatus closes or breaks in electric circuit is harmful to the contacts, insulation, and reliability of electrical gear because of its very high temperature. As arcing time is very short in switching gear, it is very difficult to observe arc phenomena directly for researchers. Therefore, visualization of switching arc is important for understanding arc phenomena, to analyze the arc features, and to improve the design and reliability of switching gear. Based on analyzing the visualization methods proposed by researchers, a new switching arc capturing approach is introduced in this paper. Arc image acquisition, and image processing techniques were studied. A switching arc image acquisition and visual simulation software based on high speed CCD camera hard ware system was designed and implemented to yield enhanced arc image with good visual effect.

  9. Making and breaking an Island arc: a new perspective from the Oligocene Kyushu-Palau arc

    Science.gov (United States)

    Ishizuka, O.; Taylor, R. N.; Yuasa, M.; Ohara, Y.

    2010-12-01

    The Kyushu-Palau Ridge (KPR) is a 2000km long remnant island arc that is separated from the active Izu-Bonin-Mariana (IBM) arc system by a series of spreading and rift basins. In this study we present 40Ar/39Ar ages and geochemical data for new samples taken from the entire length of the Kyushu-Palau arc. As such, this data provides the first comprehensive evaluation of temporal and spatial changes that are present in an Eocene-Oligocene island arc. Kyushu-Palau arc geochemistry is evaluated alongside new data from the conjugate arc which is stranded within the IBM fore-arc. Boninitic magmatism gave way to transitional arc suites including high-Mg andesites at c. 45 Ma (Ishizuka et al., 2006). After the transitional 45-41 Ma period, a mature arc system developed through the Eocene-Oligocene time: This volcanism is now preserved as the KPR. Dating results from 33 sites indicate that the KPR was active between 25 and 43 Ma, but the majority of the exposed volcanism occurred in the final phase of this arc, between 25 and 27 Ma. Unlike the IBM, the KPR has only limited systematic along-arc trends and does not include any of the strongly HIMU lavas found to the south of Izu-Bonin. Two components found along the KPR are found to have geochemistry that suggests an origin in the supra-subduction mantle rather than from the descending ocean crust. Firstly, in the south of the arc, EM-2-like lavas are present where the West Philippine Basin was in the final stages of spreading. Secondly, EM-1-like lavas are present in a restricted section of the arc, suggesting a localised heterogeneity. Subduction flux beneath the KPR generally imparted a Pb isotope vector towards low Δ8/4 (19). This is a similar trend to the Eocene/Oligocene lavas found on the eastern side of the basins which split the arc at 25Ma. Another geochemical heterogeneity is found at the KPR-Daito Ridge intersection where arc magmatism occurred on pre-existing Daito Ridge crust: a Cretaceous remnant arc

  10. Vacuum arc under axial magnetic fields: experimental and simulation research

    International Nuclear Information System (INIS)

    Axial magnetic field (AMF) technology is a most important control method of vacuum arc, particularly for high-current vacuum arcs in vacuum interrupters. In this paper, a review of the state of current research on vacuum arcs under AMF is presented. The major aspects of vacuum arc in an AMF such as arc voltage, the motion of cathode spots, and anode activities are discussed, and the most recent progress both of experimental and simulation research is presented. (topical review)

  11. THE REDSHIFT DISTRIBUTION OF GIANT ARCS IN THE SLOAN GIANT ARCS SURVEY

    International Nuclear Information System (INIS)

    We measure the redshift distribution of a sample of 28 giant arcs discovered as a part of the Sloan Giant Arcs Survey. Gemini/GMOS-North spectroscopy provides precise redshifts for 24 arcs, and 'redshift desert' constrains for the remaining 4 arcs. This is a direct measurement of the redshift distribution of a uniformly selected sample of bright giant arcs, which is an observable that can be used to inform efforts to predict giant arc statistics. Our primary giant arc sample has a median redshift z = 1.821 and nearly two-thirds of the arcs, 64%, are sources at z ∼> 1.4, indicating that the population of background sources that are strongly lensed into bright giant arcs resides primarily at high redshift. We also analyze the distribution of redshifts for 19 secondary strongly lensed background sources that are not visually apparent in Sloan Digital Sky Survey imaging, but were identified in deeper follow-up imaging of the lensing cluster fields. Our redshift sample for the secondary sources is not spectroscopically complete, but combining it with our primary giant arc sample suggests that a large fraction of all background galaxies that are strongly lensed by foreground clusters reside at z ∼> 1.4. Kolmogorov-Smirnov tests indicate that our well-selected, spectroscopically complete primary giant arc redshift sample can be reproduced with a model distribution that is constructed from a combination of results from studies of strong-lensing clusters in numerical simulations and observational constraints on the galaxy luminosity function.

  12. Birth control failure.

    Science.gov (United States)

    Sophocles, A M

    1986-10-01

    Birth control failure usually results from the incorrect or inconsistent use of contraceptives. By providing anticipatory counseling, based on an understanding of the reasons for birth control failure, family physicians can help curtail the current epidemic of unwanted pregnancies. PMID:3766356

  13. Sulphasalazine induced renal failure.

    OpenAIRE

    Dwarakanath, A D; Michael, J.; Allan, R. N.

    1992-01-01

    Two men with longstanding ulcerative colitis who were treated with sulphasalazine for several years and who developed chronic renal failure are reported. Renal biopsy specimens showed histological changes consistent with drug induced chronic intestinal nephritis. Extensive investigation made other causes of chronic renal failure unlikely. One of these patients underwent renal transplantation, the other has impaired but stable renal function.

  14. Generalized energy failure criterion.

    Science.gov (United States)

    Qu, R T; Zhang, Z J; Zhang, P; Liu, Z Q; Zhang, Z F

    2016-01-01

    Discovering a generalized criterion that can predict the mechanical failure of various different structural materials is one of ultimate goals for scientists in both material and mechanics communities. Since the first study on the failure criterion of materials by Galileo, about three centuries have passed. Now we eventually find the "generalized energy criterion", as presented here, which appears to be one universal law for various different kinds of materials. The validity of the energy criterion for quantitatively predicting the failure is experimentally confirmed using a metallic glass. The generalized energy criterion reveals the competition and interaction between shear and cleavage, the two fundamental inherent failure mechanisms, and thus provides new physical insights into the failure prediction of materials and structural components. PMID:26996781

  15. Generalized energy failure criterion

    Science.gov (United States)

    Qu, R. T.; Zhang, Z. J.; Zhang, P.; Liu, Z. Q.; Zhang, Z. F.

    2016-01-01

    Discovering a generalized criterion that can predict the mechanical failure of various different structural materials is one of ultimate goals for scientists in both material and mechanics communities. Since the first study on the failure criterion of materials by Galileo, about three centuries have passed. Now we eventually find the “generalized energy criterion”, as presented here, which appears to be one universal law for various different kinds of materials. The validity of the energy criterion for quantitatively predicting the failure is experimentally confirmed using a metallic glass. The generalized energy criterion reveals the competition and interaction between shear and cleavage, the two fundamental inherent failure mechanisms, and thus provides new physical insights into the failure prediction of materials and structural components. PMID:26996781

  16. SOR-ring failure

    International Nuclear Information System (INIS)

    It was in the autumn of 1976 that the SOR-ring (synchrotron radiation storage ring) has commenced the regular operation. Since then, the period when the operation was interrupted due to the failures of SOR-ring itself is in total about 8 weeks. Failures and accidents have occurred most in the vacuum system. Those failure experiences are described on the vacuum, electromagnet, radio-frequency acceleration and beam transport systems with their interrupted periods. The eleven failures in the vacuum system have been reported, such as bellows breakage in a heating-evacuating period, leakage from the bellows of straight-through valves (made in U.S.A. and Japan), and leakage from the joint flange of the vacuum system. The longest interruption was 5 weeks due to the failure of a domestically manufactured straight-through valve. The failures of the electromagnet system involve the breakage in a cooling water system, short circuit of a winding in the Q magnet power transformer, blow of a fuse protecting the deflection magnet power source by the current less than the rating, and others. The failures of the RF acceleration system include the breakage of an output electronic tube the breakage of a cavity ceramic, RF voltage fluctuation due to the contact deterioration at a cavity electrode, and the failure of grid bias power source. It is necessary to select the highly reliable components for the vacuum system because the vacuum system failures require longer time for recovery, and very likely to induce secondary and tertiary failures. (Wakatsuki, Y.)

  17. Gas Tungsten Arc Welding of Copper and Mild Steel

    Directory of Open Access Journals (Sweden)

    Daniel T

    2016-06-01

    Full Text Available In this paper, copper and mild steel were welded using a gas tungsten arc welding (GTAW process. To determine the weldablity factor, tests are needed to provide information on mechanical strength, potential defects in structure, and nature of failure. Mechanical testing included transverse tensile tests, micro hardness tests, and bend tests. The results for the transverse tensile test revealed failure occurred at the copper heat affected zone (HAZ with an ultimate tensile strength of 220MPa. The weld metal produced the highest average hardness value of 173HV. The bend tests revealed small cracks on the surfaces of each bend and the nature of the bend, bent around the copper HAZ. Metallography revealed ferrite (α and copper (ε cellular and dendritic shaped microstructure in the weld metal. Post weld heat treatment (PWHT was attempted to observe if any improvements on strength could be achieved. Tensile and micro hardness tests revealed the copper base metal increased in ductility significantly and in the weld metal slightly increased in ductility

  18. Episodicity in back-arc tectonic regimes

    Science.gov (United States)

    Clark, Stuart R.; Stegman, Dave; Müller, R. Dietmar

    2008-12-01

    The evolution of back-arc basins is tied to the development of the dynamics of the subduction system they are a part of. We present a study of back-arc basins and model their development by implementing 3D time-dependant computer models of subduction including an overriding plate. We define three types of episodicity: pseudo-, quasi- and hyper-episodicity, and find evidence of these in nature. Observations of back-arc basin ages, histories of spreading, quiescence and compression in the overriding plate give us an understanding of the time-development of these subduction zones and back-arc basins. Across the globe today, a number of trenches are advancing—the Izu-Bonin Trench, the Mariana Trench, the Japan Trench, the Java-Sunda Trench and the central portion of the Peru-Chile Trench (the Andes subduction zone). The Izu-Bonin, Mariana and Japan all have established back-arc basins, while the others have documented episodes of spreading, quiescence, compression or a combination of these. The combination of advancing and retreating trench motion places these subduction zones in the category of hyper-episodicity. Quasi-episodicity, in which the back-arc shifts between phases of rifting, spreading and quiescence, is the dominant form of episodic back-arc development in the present. We find this type of episodicity in models for which the system is dynamically consistent—that we have allowed the subducting plate's velocity to be determined by the sinking slabs' buoyancy. Quasi- and hyper-episodicity are only found in subduction zones with relatively high subducting plate velocities, between 6 and 9 cm/year. Finally, those subduction zones for which the subducting plate is moving slowly, such as in the Mediterranean or the Scotia Sea, experience only pseudo-episodicity, where the spreading moves linearly towards the trench but often does so in discrete ridge-jump events.

  19. arcControlTower: the System for Atlas Production and Analysis on ARC

    International Nuclear Information System (INIS)

    PanDA, the Atlas management and distribution system for production and analysis jobs on EGEE and OSG clusters, is based on pilot jobs to increase the throughput and stability of the job execution on grid. The ARC middleware uses a specific approach which tightly connects the job requirements with cluster capabilities like resource usage, software availability and caching of input files. The pilot concept renders the ARC features useless. The arcControlTower is the job submission system which merges the pilot benefits and ARC advantages. It takes the pilot payload from the panda server and submits the jobs to the Nordugrid ARC clusters as regular jobs, with all the job resources known in advance. All the pilot communication with the PanDA server is done by the arcControlTower, so it plays the role of a pilot factory and the pilot itself. There are several advantages to this approach: no grid middleware is needed on the worker nodes, the fair-share between the production and user jobs is tuned with the arcControlTower load parameters, the jobs can be controlled by ARC client tools. The system could be extended to other submission systems using central distribution.

  20. Effect of arc distance on temperature field and weld shape during double-sided arc welding

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guangjun; ZHANG Huajun; GAO Hongming; WU Lin

    2009-01-01

    A new high efficiency welding method, double-sided double arc welding with double powers (DSAW-D), is developed for thick plate of low alloy high strength steel in this study. It is well known that the thermal cycles have an important influence on the microstructure, shape, stress, distortion and mechanical property. The DSA W-D method can control the tempernture field on a wide range by regulating the distance between two arcs, improve the rnicrostructure and prevent hot and cold cracking of high strength steel. But at present, the effect of arc distance on the temperature field and shape is not clear. Therefore, the paper researches the effect of arc distance on the temperature field and weld pool during DSA W-D using finite element method. The transient temperature field of different arc distance in DSAW-D is calculated.To verify the numerical results, the temperature is measured by the thermo-couple and the calculated results agree approximately with experimental data. Farther, the thermal property and mutual effect of double-sided arcs are investigated. The temperature distributions and weld pool profile at different arc distances are obtained. The results show that arc distance is a very important factor to affect the heat process.

  1. ANALYSIS OF ENERGY AND MASS FLOWS IN AN ARC HEATER WITH INTENSIVELY BLOWN ELECTRIC ARC

    Czech Academy of Sciences Publication Activity Database

    Gregor, Jan; Jakubová, I.; Šenk, J.

    Brno : Masaryk University, 2008. s. 173-174. ISBN N. [Central European Symposium on Plasma Chemistry/2nd./. 31.08.2008-04.09.2008, Brno] Institutional research plan: CEZ:AV0Z20430508 Keywords : Electric arc * mathematical model * energy flows * temperature distribution * velocity distribution * electric intensity * arc radius Subject RIV: BL - Plasma and Gas Discharge Physics

  2. Slab-derived fluids, fore-arc hydration, and sub-arc magmatism beneath Kyushu, Japan

    Science.gov (United States)

    Saita, Hiroto; Nakajima, Junichi; Shiina, Takahiro; Kimura, Jun-Ichi

    2015-03-01

    We estimate the three-dimensional (3-D) P wave attenuation structure beneath Kyushu, Japan, using a large number of high-quality waveform data. Our results show that the mantle wedge is characterized by high-attenuation regions in the fore-arc corner and in the back-arc beneath volcanoes, with the two regions separated by a low-attenuation area. The volcanic gap in central Kyushu is underlain by low attenuation below the Moho. High attenuation in the fore arc is probably associated with serpentinized peridotite, while that in the back arc is interpreted as an upwelling flow that is the source of arc magmas. The presence of low-attenuation mantle that separates the high-attenuation hydrated, fore-arc, and back-arc mantle regions suggests that fluids are supplied from two depth levels of the slab by different mechanisms. Low attenuation beneath the volcanic gap probably results from intricate 3-D mantle flow that is caused by tectonic processes such as back-arc extension and ridge collision.

  3. Effect of acoustic field parameters on arc acoustic binding during ultrasonic wave-assisted arc welding.

    Science.gov (United States)

    Xie, Weifeng; Fan, Chenglei; Yang, Chunli; Lin, Sanbao

    2016-03-01

    As a newly developed arc welding method, power ultrasound has been successfully introduced into arc and weld pool during ultrasonic wave-assisted arc welding process. The advanced process for molten metals can be realized by utilizing additional ultrasonic field. Under the action of the acoustic wave, the plasma arc as weld heat source is regulated and its characteristics make an obvious change. Compared with the conventional arc, the ultrasonic wave-assisted arc plasma is bound significantly and becomes brighter. To reveal the dependence of the acoustic binding force on acoustic field parameters, a two-dimensional acoustic field model for ultrasonic wave-assisted arc welding device is established. The influences of the radiator height, the central pore radius, the radiator radius, and curvature radius or depth of concave radiator surface are discussed using the boundary element method. Then the authors analyze the resonant mode by this relationship curve between acoustic radiation power and radiator height. Furthermore, the best acoustic binding ability is obtained by optimizing the geometric parameters of acoustic radiator. In addition, three concave radiator surfaces including spherical cap surface, paraboloid of revolution, and rotating single curved surface are investigated systematically. Finally, both the calculation and experiment suggest that, to obtain the best acoustic binding ability, the ultrasonic wave-assisted arc welding setup should be operated under the first resonant mode using a radiator with a spherical cap surface, a small central pore, a large section radius and an appropriate curvature radius. PMID:26558995

  4. Method to reduce arc blow during DC arc welding of pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Espina-Hernandez, J. H.; Rueda-Morales, G.L.; Caleyo, F.; Hallen, J. M. [Instituto Politecnico Nacional, Mexico, (Mexico); Lopez-Montenegro, A.; Perz-Baruch, E. [Pemex Exploracion y Produccion, Tabasco, (Mexico)

    2010-07-01

    Steel pipelines are huge ferromagnetic structures and can be easily subjected to arc blow during the DC arc welding process. The development of methods to avoid arc blow during pipeline DC arc welding is a major objective in the pipeline industry. This study developed a simple procedure to compensate the residual magnetic field in the groove during DC arc welding. A Gaussmeter was used to perform magnetic flux density measurements in pipelines in southern Mexico. These data were used to perform magnetic finite element simulations using FEMM. Different variables were studied such as the residual magnetic field in the groove or the position of the coil with respect to the groove. An empirical predictive equation was developed from these trials to compensate for the residual magnetic field. A new method of compensating for the residual magnetic field in the groove by selecting the number of coil turns and the position of the coil with respect to the groove was established.

  5. Research of Arc Chamber Optimization Techniques Based on Flow Field and Arc Joint Simulation

    Science.gov (United States)

    Zhong, Jianying; Guo, Yujing; Zhang, Hao

    2016-03-01

    The preliminary design of an arc chamber in the 550 kV SF6 circuit breaker was proposed in accordance with the technical requirements and design experience. The structural optimization was carried out according to the no-load flow field simulation results and verified by no-load pressure measurement. Based on load simulation results such as temperature field variation at the arc area and the tendency of post arc current under different recovery voltage, the second optimal design was completed and its correctness was certificated by a breaking test. Results demonstrate that the interrupting capacity of an arc chamber can be evaluated by the comparison of the gas medium recovery speed and post arc current growth rate.

  6. The geochemistry and petrogenesis of the Paleoproterozoic Green Mountain arc: A composite(?), bimodal, oceanic, fringing arc

    Science.gov (United States)

    Jones, D.S.; Barnes, C.G.; Premo, W.R.; Snoke, A.W.

    2011-01-01

    The inferred subduction affinity of the ~1780-Ma Green Mountain arc, a dominantly bimodal igneous terrane (together with immature marine and volcaniclastic sedimentary rocks) accreted to the southern margin of the Wyoming province, is integral to arc-accretion models of the Paleoproterozoic growth of southern Laurentia. Conversely, the dominantly bimodal nature of many putative arc-related igneous suites throughout southern Laurentia, including the Green Mountain arc, has also been used to support models of growth by extension of pre-existing crust. We report new geochemical and isotopic data from ~1780-Ma gabbroic and granodioritic to tonalitic rocks of the Big Creek Gneiss, interpreted as consanguineous with previously studied metavolcanic rocks of the Green Mountain Formation.The ~1780-Ma Big Creek Gneiss mafic rocks show clear geochemical signatures of a subduction origin and provide no supporting evidence for extensional tectonism. The ~1780-Ma Big Creek Gneiss felsic rocks are attributed to partial melting of mafic and/or mixed lower-crustal material. The bimodal nature of the suite results from the combination of arc basalts and felsic crustal melts. The lack of andesite is consistent with the observed tholeiitic differentiation trend of the mafic magmas. The lower e{open}Nd(1780Ma) values for the felsic rocks vs. the mafic rocks suggest that the unexposed lower crust of the arc may be older than the arc and that Trans-Hudson- or Penokean-aged rocks possibly form the substratum of the arc. Our results reinforce previous interpretations that arc-related magmatism played a key role in the Paleoproterozoic crustal growth of southern Laurentia, but also support the possibility of unexposed older crust as basement to the arcs. ?? 2011 Elsevier B.V.

  7. Auxiliary-Arc Electrodes for MHD Systems

    International Nuclear Information System (INIS)

    The important role of electrode phenomena in the operation of magneto aerodynamic machines is well known. In particular, the voltage drops which occur in the boundary layer in the immediate neighbourhood of the electrode may reduce the output of the apparatus. These voltage drops are caused partly by the increased resistance presented by the boundary layer in the neighbourhood of the electrode when the latter is appreciably colder than the gas, and partly by the fact that the electrode is not at a temperature sufficient to be emissive. Auxiliary-arc electrodes that have been constructed and tested seem to provide a solution both of the cold boundary layer problem and of the cathode emissivity problem. For this purpose an arc is established between a refractory metal cathode placed behind and clear of the generator wall and an anode forming part of the wall. The arc column can be activated by a rotational movement under the effect of a magnetic field, which may be that of the machine itself. The mechanical arrangement of the electrodes is such that, with a weak flow of gas (argon for example), it is possible to maintain a protective atmosphere around the arc cathode, while the arc anode is strongly cooled by the wall. The gas flow also has the effect of forcing the arc column towards the stream, thus increasing the conductivity of the boundary layer. Furthermore, the arc column behaves as a virtual cathode, from which a sizeable electron current can be extracted. Electrodes constructed on this principle have been tested on gas streams composed of fuel-oil combustion products. By using them as cathodes it has been possible to extract a current of 5 A without the voltage drop between the electrode and the gas exceeding 10 V. Comparative tests have been carried out with cooled metal electrodes, in which case the voltage drop is of the order of 120 V. The arc electrodes tested have operated for several hours without any apparent damage. In spite of the energy which has

  8. MERGERS - SUCCESS OR FAILURE?

    Directory of Open Access Journals (Sweden)

    Irina Sandu căs. Chiriac

    2011-03-01

    Full Text Available Mergers are transactions of great importance, not only for organizations involved, but for many stakeholders. Success or failure of such enterprises may have consequences enormous for the shareholders of an organization, creditors, employees, competitors and community. Empirical evidence indicates a high rate of failure of mergers in terms of create value for shareholders. This study examines the causes of merger failure and offers a possible solution to make the merger successful. The internal audit has evolved from its traditional role to an active advisory. Internal auditors can ensure successful merger process.

  9. Damage mechanics - failure modes

    Energy Technology Data Exchange (ETDEWEB)

    Krajcinovic, D.; Vujosevic, M. [Arizona State Univ., Tempe, AZ (United States)

    1996-12-31

    The present study summarizes the results of the DOE sponsored research program focused on the brittle failure of solids with disordered microstructure. The failure is related to the stochastic processes on the microstructural scale; namely, the nucleation and growth of microcracks. The intrinsic failure modes, such as the percolation, localization and creep rupture, are studied by emphasizing the effect of the micro-structural disorder. A rich spectrum of physical phenomena and new concepts that emerges from this research demonstrates the reasons behind the limitations of traditional, deterministic, and local continuum models.

  10. Nutrition in Heart Failure

    OpenAIRE

    Reci Meseri

    2013-01-01

    Heart failure is defined as decreased ability of heart due to various reasons. It%u2019s seen 2-3% but the prevalence increases sharply after the age of seventy. The objectives of nutrition therapy in heart failure are to prevent from water retention and edema, to avoid from hard digestion and to offer a balanced diet. In order to avoid fluid retention and edema, daily sodium and fluid intake must be monitored carefully. Main dilemma of the heart failure patients is the obesity-cachexia dilem...

  11. Study on Expansion Process of EDM Arc Plasma

    Science.gov (United States)

    Natsu, Wataru; Shimoyamada, Mayumi; Kunieda, Masanori

    In order to understand the phenomena of electrical discharge machining (EDM), the characteristics of transition arc plasma in EDM were investigated. The arc plasma was directly observed with a high speed video camera. In addition, to learn more about arc plasma expansion, plasma temperature was measured by spectroscopy. The arc plasma temperature was obtained by measuring the radiant fluxes of two different wavelengths from the arc plasma and applying the line pair method. Furthermore, a new expansion model for EDM arc plasma was proposed based on the observations, and validated by comparing experimental and computed results of the discharge crater.

  12. Photoelectric detection electric arc in energetic arrangements

    Science.gov (United States)

    Leks, Jan

    2001-08-01

    The evolution of photoelectric converter, fiber optics and integrated circuits, in particular optic detectors, increases area of applying of the industrial measuring and control systems that used IR detectors. One of the more important is optic detection of electric arc in industrial energetic arrangements. That kind of detection is sure, easy to apply in existing industrial apparatus a d it is cheaper than another way of detection. Additionally optic detection of electric arc is safety for attendance persons and may work on computer system. The article presents an example of circuit with semiconductor IR photoelectric detector to detection of electric arc and points at the most important questions which should be taken into consideration in designing instruments like described one.

  13. Circular arc snakes and kinematic surface generation

    KAUST Repository

    Barton, Michael

    2013-05-01

    We discuss the theory, discretization, and numerics of curves which are evolving such that part of their shape, or at least their curvature as a function of arc length, remains unchanged. The discretization of a curve as a smooth sequence of circular arcs is well suited for such purposes, and allows us to reduce evolution of curves to the evolution of a control point collection in a certain finite-dimensional shape space. We approach this evolution by a 2-step process: linearized evolution via optimized velocity fields, followed by optimization in order to exactly fulfill all geometric side conditions. We give applications to freeform architecture, including "rationalization" of a surface by congruent arcs, form finding and, most interestingly, non-static architecture. © 2013 The Author(s) Computer Graphics Forum © 2013 The Eurographics Association and Blackwell Publishing Ltd.

  14. Failure research report

    International Nuclear Information System (INIS)

    By the example of an unusual failure case on a superheater tube of a steam generator, the authors point out the disadvantageous results that carelessly performed assembly weldings can lead to. (orig./LH)

  15. Heart failure - medicines

    Science.gov (United States)

    ... are working and to measure your potassium levels. Beta Blockers Beta blockers slow your heart rate and decrease the strength ... muscle contracts in the short term. Long term beta blockers help keep your heart failure from becoming worse. ...

  16. Heart failure - palliative care

    Science.gov (United States)

    ... et al. 2013 ACCF/AHA guideline for the management of heart failure: a report of the American College ... MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, ...

  17. Premature Ovarian Failure

    Science.gov (United States)

    Premature ovarian failure (POF) is when a woman's ovaries stop working before she is 40. POF is different from ... There is no treatment that will restore normal ovarian function. However, many health care providers suggest taking ...

  18. Living with Respiratory Failure

    Science.gov (United States)

    ... tips below. Ongoing Care If you have respiratory failure, see your doctor for ongoing medical care. Your doctor may refer you to pulmonary rehabilitation (rehab). Rehab can involve exercise training, education, and counseling. Your rehab team might include doctors, ...

  19. On the Trail of Joan of Arc

    Directory of Open Access Journals (Sweden)

    Linda Joyce Forristal

    2013-12-01

    Full Text Available The year 2012 marked the 600th anniversary of the birthday of Joan of Arc (Fr., Jeanne d’Arc (1412–1431. Tributes to this national heroine can be found all over France. There are literally countless statues, streets and restaurants named after her and many sites dedicated to her life. However, despite widespread social and mechanical reproduction and cultural naming in relation to the Maid of Orléans, there is no official network or integrated signage in France to promote cultural heritage tourism to the numerous Joan of Arc sites and festivals, even though her life and death, by any measure, were seminal events in the country’s history. Unfortunately, the pilgrim who wants to follow or intersect with Joan of Arc’s trail through France, for cultural, historical or religious reasons, must do so without much help. Using Actor Network Theory and Site Sacralization Theory as framing devices, this paper explores human actors and tangible and intangible non-human factors that may have contributed to the lack of a unified tourism product despite the existence of an adequate Joan of Arc tourismscape. Insights gleaned from this research include Joan’s conflicted status as both/either saint and/or patriot, the existence of no cooperation or linkage between Joan of Arc sites, and cautious French tourism development policies. Several possible scenarios are suggested as suitable means to help implement or foster the creation of an on-the-ground or virtual Joan of Arc trail or tour.

  20. Evaporation Erosion During the Relay Contact Breaking Process Based on a Simplified Arc Model

    Science.gov (United States)

    Cui, Xinglei; Zhou, Xue; Zhai, Guofu; Peng, Xiyuan

    2016-05-01

    Evaporation erosion of the contacts is one of the fundamental failure mechanisms for relays. In this paper, the evaporation erosion characteristics are investigated for the copper contact pair breaking a resistive direct current (dc) 30 V/10 A circuit in the air. Molten pool simulation of the contacts is coupled with the gas dynamics to calculate the evaporation rate. A simplified arc model is constructed to obtain the contact voltage and current variations with time for the prediction of the current density and the heat flux distributions flowing from the arc into the contacts. The evaporation rate and mass variations with time during the breaking process are presented. Experiments are carried out to verify the simulation results. supported by National Natural Science Foundation of China (Nos. 51377038, 51307030)

  1. Evaporation Erosion During the Relay Contact Breaking Process Based on a Simplified Arc Model

    Institute of Scientific and Technical Information of China (English)

    CUI Xinglei; ZHOU Xue; ZHAI Guofu; PENG Xiyuan

    2016-01-01

    Evaporation erosion of the contacts is one of the fundamental failure mechanisms for relays.In this paper,the evaporation erosion characteristics are investigated for the copper contact pair breaking a resistive direct current (dc) 30 V/10 A circuit in the air.Molten pool simulation of thc contacts is coupled with the gas dynamics to cMculate the evaporation rate.A simplified arc model is constructed to obtain the contact voltage and current variations with time for the prediction of the current density and the heat flux distributions flowing from the arc into the contacts.The evaporation rate and mass variations with time during the breaking process are presented.Experiments are carried out to verify the simulation results.

  2. Renal failure (chronic)

    OpenAIRE

    Clase, Catherine

    2009-01-01

    Chronic renal failure is characterised by a gradual and sustained decline in renal clearance or glomerular filtration rate (GFR). Continued progression of renal failure will lead to renal function too low to sustain healthy life. In developed countries, such people will be offered renal replacement therapy in the form of dialysis or renal transplantation. Requirement for dialysis or transplantation is termed end-stage renal disease (ESRD).Diabetes, glomerulonephritis, hypertension, pyelone...

  3. ArcAid interactive archery assistant

    OpenAIRE

    Jeroen Vervaeke; Jente Ameye; Sievert van Esch; Jelle Saldien; Steven Verstockt

    2015-01-01

    This paper describes the design process of a bow aiming system, called ArcAid, which is an interactive archery assistant. The main goal of ArcAid is to introduce a way for beginner Robin Hoods to learn the art of archery to its fullest. In order to achieve this goal, our smartphone-based design focuses on a fun and interactive learning process that gives constant feedback to the user on how to hit a certain goal. A SPIKE high- end laser sensor is used for the distance measurement and the smar...

  4. Electric-arc steam plasma generator

    Science.gov (United States)

    Anshakov, A. S.; Urbakh, E. K.; Radko, S. I.; Urbakh, A. E.; Faleev, V. A.

    2015-01-01

    Investigation results on the arc plasmatorch for water-steam heating are presented. The construction arrangement of steam plasma generator with copper electrodes of the stepped geometry was firstly implemented. The energy characteristics of plasmatorch and erosion of electrodes reflect the features of their behavior at arc glow in the plasma-forming environment of steam. The results of numerical study of the thermal state of the composite copper-steel electrodes had a significant influence on optimization of anode water-cooling aimed at improvement of its operation life.

  5. Dynamic Arc-Flags in Road Networks

    OpenAIRE

    D 'angelo, Gianlorenzo; Frigioni, Daniele; Vitale, Camillo

    2011-01-01

    International audience In this work we introduce a new data structure, named Road-Signs, which allows us to efficiently update the Arc-Flags of a graph in a dynamic scenario. Road-Signs can be used to compute Arc-Flags, can be efficiently updated and do not require large space consumption for many real-world graphs like, e.g., graphs arising from road networks. In detail, we define an algorithm to preprocess Road-Signs and an algorithm to update them each time that a weight increase operat...

  6. Architectural Surfaces and Structures from Circular Arcs

    KAUST Repository

    Shi, Ling

    2013-12-01

    In recent decades, the popularity of freeform shapes in contemporary architecture poses new challenges to digital design. One of them is the process of rationalization, i.e. to make freeform skins or structures affordable to manufacture, which draws the most attention from geometry researchers. In this thesis, we aim to realize this process with simple geometric primitives, circular arcs. We investigate architectural surfaces and structures consisting of circular arcs. Our focus is lying on how to employ them nicely and repetitively in architectural design, in order to decrease the cost in manufacturing. Firstly, we study Darboux cyclides, which are algebraic surfaces of order ≤ 4. We provide a computational tool to identify all families of circles on a given cyclide based on the spherical model of M ̈obius geometry. Practical ways to design cyclide patches that pass through certain inputs are presented. In particular, certain triples of circle families on Darboux cyclides may be suitably arranged as 3-webs. We provide a complete classification of all possible 3-webs of circles on Darboux cyclides. We then investigate the circular arc snakes, which are smooth sequences of circu- lar arcs. We evolve the snakes such that their curvature, as a function of arc length, remains unchanged. The evolution of snakes is utilized to approximate given surfaces by circular arcs or to generated freeform shapes, and it is realized by a 2-step pro- cess. More interestingly, certain 6-arc snake with boundary constraints can produce a smooth self motion, which can be employed to build flexible structures. Another challenging topic is approximating smooth freeform skins with simple panels. We contribute to this problem area by approximating a negatively-curved 5 surface with a smooth union of rational bilinear patches. We provide a proof for vertex consistency of hyperbolic nets using the CAGD approach of the rational B ́ezier form. Moreover, we use Darboux transformations for the

  7. A numerical simulation of ablation controlled arcs

    Energy Technology Data Exchange (ETDEWEB)

    Godin, D.; Trepanier, J.Y. [Ecole Polytechnique, Dept. of Mechanical Engineering, Montreal, PQ (Canada); Eby, S.D. [Ecole Polytechnique, Centre de Recherche en Calcul Applique, Montreal, PQ (Canada); Robin-Jouan, P. [GEC-Alsthom T and D, Villeurbanne, (France)

    1998-09-01

    An approach to model the ablation phenomenon of ablation controlled arcs using computational fluid dynamics was presented. Ablation controlled arcs are found in high voltage electrical equipment such as fuses and circuit-breakers. A qualitative prediction of the ablation level is critical from an industrial point of view because deliberate use of ablation is made to increase the pressure in a circuit-breaker chamber to allow for an efficient extinction when the current returns to zero. The numerical model was validated by comparing results of published experimental data. 7 refs., 10 figs.

  8. Small Universal Petri Nets with Inhibitor Arcs

    OpenAIRE

    Ivanov, Sergiu; Pelz, Elisabeth; Verlan, Sergey

    2013-01-01

    We investigate the problem of construction of small-size universal Petri nets with inhibitor arcs. We consider four descriptional complexity parameters: the number of places, transitions, inhibitor arcs, and the maximal degree of a transition, each of which we try to minimize. We give six constructions having the following values of parameters (listed in the above order): $(30,34,13,3)$, $(14, 31, 51, 8)$, $(11, 31, 79, 11)$, $(21,25,13,5)$, $(67, 64, 8, 3)$, $(58, 55, 8, 5)$ that improve the...

  9. Plasma distribution of cathodic ARC deposition system

    Energy Technology Data Exchange (ETDEWEB)

    Anders, S.; Raoux, S.; Krishnan, K.; MacGill, R.A.; Brown, I.G. [Lawrence Berkeley National Lab., CA (United States)

    1996-08-01

    The plasma distribution using a cathodic arc plasma source with and without magnetic macroparticle filter has been determined by depositing on a transparent plastic substrate and measuring the film absorption. It was found that the width of the distribution depends on the arc current, and it also depends on the cathode material which leads to a spatial separation of the elements when an alloy cathode is used. By applying a magnetic multicusp field near the exit of the magnetic filter, it was possible to modify the plasma distribution and obtain a flat plasma profile with a constant and homogeneous elemental distribution.

  10. Lungs in Heart Failure

    Directory of Open Access Journals (Sweden)

    Anna Apostolo

    2012-01-01

    Full Text Available Lung function abnormalities both at rest and during exercise are frequently observed in patients with chronic heart failure, also in the absence of respiratory disease. Alterations of respiratory mechanics and of gas exchange capacity are strictly related to heart failure. Severe heart failure patients often show a restrictive respiratory pattern, secondary to heart enlargement and increased lung fluids, and impairment of alveolar-capillary gas diffusion, mainly due to an increased resistance to molecular diffusion across the alveolar capillary membrane. Reduced gas diffusion contributes to exercise intolerance and to a worse prognosis. Cardiopulmonary exercise test is considered the “gold standard” when studying the cardiovascular, pulmonary, and metabolic adaptations to exercise in cardiac patients. During exercise, hyperventilation and consequent reduction of ventilation efficiency are often observed in heart failure patients, resulting in an increased slope of ventilation/carbon dioxide (VE/VCO2 relationship. Ventilatory efficiency is as strong prognostic and an important stratification marker. This paper describes the pulmonary abnormalities at rest and during exercise in the patients with heart failure, highlighting the principal diagnostic tools for evaluation of lungs function, the possible pharmacological interventions, and the parameters that could be useful in prognostic assessment of heart failure patients.

  11. Arcing Model of a Disconnector and its Effect on VFTO

    International Nuclear Information System (INIS)

    In the computational process of very fast transient over-voltage (VFTO), it is essential to find an accurate model for a gas insulated substation. The arcing model of the disconnector is particularly important. The general arcing model is not able to give a good description of the arc development process. In this paper, based on the physical process of arcing and existing arc models (the exponential time-varying resistance model and the segmental arcing models), a dynamic arcing model is proposed, which is divided into two stages before and after the zero crossing. The dynamic arcing model combines hyperbola time-varying resistance and the Mayr model to describe the dynamic process of arcing. The present paper creates an arc model blockset upon the Matlab/Simulink software platform. Moreover for a specific 1100 kV station, VFTO is simulated in detail based on different arcing models. It is demonstrated that the dynamic arcing model can describe the physical arc process precisely and is useful for improving the accuracy of VFTO simulations

  12. PNW River Reach Files -- 1:100k Watercourses (arcs)

    Data.gov (United States)

    Pacific States Marine Fisheries Commission — This feature class includes the ARC features from the 2001 version of the PNW River Reach files Arc/INFO coverage. Separate, companion feature classes are also...

  13. Modeling Vacuum Arcs On Spacecraft Solar Panel Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Spacecraft charging and subsequent vacuum arcing poses a significant threat to satellites in LEO and GEO plasma conditions. Localized arc discharges can cause a...

  14. Stochastic properties of circuit breaking arcs

    Science.gov (United States)

    Rothhardt, L.

    1985-09-01

    Results are discussed for research work concerning the influence of cooling gas turbulence onto the breaker arc and the dielectric properties of the widely used cooling gases, air, and SF6, at elevated temperatures, both needed for numerical simulation of the breaking action.

  15. Rejuvenating Allen's Arc with the Geometric Mean.

    Science.gov (United States)

    Phillips, William A.

    1994-01-01

    Contends that, despite ongoing criticism, Allen's arc elasticity formula remains entrenched in the microeconomics principles curriculum. Reviews the evolution and continuing scrutiny of the formula. Argues that the use of the geometric mean offers pedagogical advantages over the traditional arithmetic mean approach. (CFR)

  16. ArcAid Interactive Archery Assistant

    Directory of Open Access Journals (Sweden)

    Jeroen Vervaeke

    2015-12-01

    Full Text Available This paper describes the design process of a bow aiming system, called ArcAid, which is an interactive archery assistant. The main goal of ArcAid is to introduce a way for beginner Robin Hoods to learn the art of archery to its fullest. In order to achieve this goal, our smartphone-based design focuses on a fun and interactive learning process that gives constant feedback to the user on how to hit a certain goal. A SPIKE high- end laser sensor is used for the distance measurement and the smartphone’s accelerometer is used to define the angle of inclination. To measure the force on the arrow and the displacement of the string, a flex sensor is attached upon one of the arcs of the bow. All sensor data is processed in an Arduino Nano microprocessor and feedback to the user is given by a dedicated smartphone app. In this paper, we mainly focus on the construction, mechanics and electronics of the ArcAid bow and on the design of the mobile app, which is the game controller. Furthermore, we briefly discuss some future development ideas.

  17. Secondary arc description on satellite solar generators

    OpenAIRE

    Crispel, Pierre; Degond, Pierre; Vignal, Marie-Helene; Roussel, Jean-Francois; Amorim, Emmanuel; Payan, Denis; Cho, Mengu

    2005-01-01

    In this paper, we propose a quasi-neutral model with non-vanishing current describing the expansion of a plasma in an inter-cellular gap on a satellite solar array. Moreover, an electric arc cathode spot model is proposed in order to give suitable boundary conditions for the expansion model.

  18. Thermal Plasma Generators with Water Stabilized Arc

    Czech Academy of Sciences Publication Activity Database

    Hrabovský, Milan

    2009-01-01

    Roč. 2, č. 1 (2009), s. 99-104. ISSN 1876-5343 R&D Projects: GA ČR GA202/08/1084 Institutional research plan: CEZ:AV0Z20430508 Keywords : Thermal plasma * plasma torch * Gerdien arc Subject RIV: BL - Plasma and Gas Discharge Physics http://www.bentham.org/open/toppj/openaccess2.htm

  19. Arc spraying solderable tabs to glass

    Science.gov (United States)

    Lindmayer, J.

    1981-01-01

    Tabs suitable for electrical or mechanical connections in solar cells and integrated circuits are made by spraying technique. Solder wets copper, copper bonds to aluminum, and aluminum adheres to glass. Arc spraying is automated and integrated with encapsulation, eliminating hand tabbing, improving reliability, and reducing cost.

  20. Portable machine welding head automatically controls arc

    Science.gov (United States)

    Oleksiak, C. E.; Robb, M. A.

    1967-01-01

    Portable weld tool makes weld repairs out-of-station and on the side opposite the original weld. It provides full automatic control of the arc voltage, current, wire feed, and electrode travel speed in all welding attitudes. The device is readily adaptable to commercially available straight polarity dc weld packs.

  1. Roadmap for the ARC Grid Middleware

    DEFF Research Database (Denmark)

    Kleist, Josva; Eerola, Paula; Ekelöf, Tord;

    2006-01-01

    The Advanced Resource Connector (ARC) or the NorduGrid middleware is an open source software solution enabling production quality computational and data Grids, with special emphasis on scalability, stability, reliability and performance. Since its first release in May 2002, the middleware is depl...

  2. Collection of arc welding process data

    Directory of Open Access Journals (Sweden)

    K. Luksa

    2006-04-01

    Full Text Available Purpose: The aim of the research was to examine the possibility of detecting welding imperfections by recording the instant values of welding parameters. The microprocessor controlled system for real-time collection and display of welding parameters was designed, implemented and tested.Design/methodology/approach: The system records up to 4 digital or analog signals collected from welding process and displays their run on the LCD display. To disturb the welding process artificial disturbances were introduced.Findings: The occurrence of some welding imperfections is followed by changes of the welding parameters. In this case they can be revealed by the analysis of the instant values of the welding parameters.Research limitations/implications: In the paper results of monitoring manual metal arc welding and gas metal arc welding are presented.Practical implications: Monitoring of gas metal arc welding is a good tool for evaluation of the quality of weld. All introduced, artificial disturbances of the welding process destabilize the welding arc and produce changes in the instant values of the welding parameters.Originality/value: The paper presents a modern microprocessor controlled system for real-time collection and display of welding parameters. Results of tests show that simple statistical approach to welding parameters can help in evaluation of weld quality.

  3. Clinical Applications of Volumetric Modulated Arc Therapy

    International Nuclear Information System (INIS)

    Purpose: To present treatment planning case studies for several treatment sites for which volumetric modulated arc therapy (VMAT) could have a positive impact; and to share an initial clinical experience with VMAT for stereotactic body radiotherapy (SBRT). Methods and Materials: Four case studies are presented to show the potential benefit of VMAT compared with conformal and intensity-modulated radiotherapy (IMRT) techniques in pediatric cancer, bone marrow-sparing whole-abdominopelvic irradiation (WAPI), and SBRT of the lung and spine. Details of clinical implementation of VMAT for SBRT are presented. The VMAT plans are compared with conventional techniques in terms of dosimetric quality and delivery efficiency. Results: Volumetric modulated arc therapy reduced the treatment time of spine SBRT by 37% and improved isodose conformality. Conformal and VMAT techniques for lung SBRT had similar dosimetric quality, but VMAT had improved target coverage and took 59% less time to deliver, although monitor units were increased by 5%. In a complex pediatric pelvic example, VMAT reduced treatment time by 78% and monitor units by 25% compared with IMRT. A double-isocenter VMAT technique for WAPI can spare bone marrow while maintaining good delivery efficiency. Conclusions: Volumetric modulated arc therapy is a new technology that may benefit different patient populations, including pediatric cancer patients and those undergoing concurrent chemotherapy and WAPI. Volumetric modulated arc therapy has been used and shown to be beneficial for significantly improving delivery efficiency of lung and spine SBRT.

  4. An approach for optimizing arc welding applications

    International Nuclear Information System (INIS)

    The dynamic and transport mechanisms involved in the arc plasma and the weld pool of arc welding operations are numerous and strongly coupled. They produce a medium the magnitudes of which exhibit rapid time variations and very marked gradients which make any experimental analysis complex in this disrupted environment. In this work, we study the TIG and MIG processes. An experimental platform was developed to allow synchronized measurement of various physical quantities associated with welding (process parameters, temperatures, clamping forces, metal transfer, etc.). Numerical libraries dedicated to applied studies in arc welding are developed. They enable the treatment of a large flow of data (signals, images) with a systematic and global method. The advantages of this approach for the enrichment of numerical simulation and arc process control are shown in different situations. Finally, this experimental approach is used in the context of the chosen application to obtain rich measurements to describe the dynamic behavior of the weld pool in P-GMAW. Dimensional analysis of these experimental measurements allows to identify the predominant mechanisms involved and to determine experimentally the characteristic times associated. This type of approach includes better description of the behavior of a macro-drop of molten metal or the phenomena occurring in the humping instabilities. (author)

  5. Evaluation of the clinical usefulness of modulated arc treatment

    Science.gov (United States)

    Lee, Young Kyu; Jang, Hong Seok; Kim, Yeon Sil; Choi, Byung Ock; Kang, Young-Nam; Nam, Sang Hee; Park, Hyeong Wook; Kim, Shin Wook; Shin, Hun Joo; Lee, Jae Choon; Kim, Ji Na; Park, Sung Kwang; Kim, Jin Young

    2015-07-01

    The purpose of this study is to evaluate the clinical usefulness of modulated arc (mARC) treatment techniques. The mARC treatment plans for non-small-cell lung cancer (NSCLC) patients were made in order to verify the clinical usefulness of mARC. A pre-study was conducted to find the best plan condition for mARC treatment, and the usefulness of the mARC treatment plan was evaluated by comparing it with other Arc treatment plans such as tomotherapy and RapidArc plans. In the case of mARC, the optimal condition for the mARC plan was determined by comparing the dosimetric performance of the mARC plans developed by using various parameters, which included the photon energy (6 MV, 10 MV), the optimization point angle (6°- 10°intervals), and the total number of segments (36 - 59 segments). The best dosimetric performance of mARC was observed at a 10 MV photon energy, a point angle 6 degrees, and 59 segments. The treatment plans for the three different techniques were compared by using the following parameters: the conformity index (CI), homogeneity index (HI), the target coverage, the dose to the OARs, the number of monitor units (MU), the beam on time, and the normal tissue complication probability (NTCP). As a result, the three different treatment techniques showed similar target coverages. The mARC plan had the lowest V20 (volume of lung receiving > 20 Gy) and MU per fraction compared with both the RapidArc and the tomotherapy plans. The mARC plan reduced the beam on time as well. Therefore, the results of this study provide satisfactory evidence that the mARC technique can be considered as a useful clinical technique for radiation treatment.

  6. PyroArc novel Waste-to-energy technology

    International Nuclear Information System (INIS)

    There is a growing interest in using solid waste as a raw material in the production of gas and materials. A new proprietary technology - called PyroArc - utilizes a wide range of waste fractions combined with a reduction of almost the entire volume. The process employs high temperature plasma technology developed by ScanArc. The Norwegian based enterprise, EnviroArc Technologies AS, has the exclusive rights to use PyroArc technology. (author)

  7. Nutrition in Heart Failure

    Directory of Open Access Journals (Sweden)

    Reci Meseri

    2013-10-01

    Full Text Available Heart failure is defined as decreased ability of heart due to various reasons. It%u2019s seen 2-3% but the prevalence increases sharply after the age of seventy. The objectives of nutrition therapy in heart failure are to prevent from water retention and edema, to avoid from hard digestion and to offer a balanced diet. In order to avoid fluid retention and edema, daily sodium and fluid intake must be monitored carefully. Main dilemma of the heart failure patients is the obesity-cachexia dilemma. Since one of the main reasons of heart failure is cardiovascular diseases, in first phase, the patient may be obese. In the later phases, cachexia may show up. It was shown that cachexia is associated with mortality. Within this period, patients should not be over-fed and the patient should pass from catabolic state to anabolic state slowly. If the gastrointestinal track is functional oral/enteral feeding must be preferred. Multi vitamin and mineral supportsmay be beneficial, which may replace the increased loss, increase anti-inflammatory response and be anti-oxidants. Large, controlled and well-designed studies must be conducted in order to evaluate the benefits of nutritional practices such as nutritional assessment, enteral feeding and nutrient supports in heart failure patients.

  8. Evaluation of the clinical usefulness of modulated Arc treatment

    CERN Document Server

    Lee, Young Kyu; Kim, Yeon Sil; Choi, Byung Ock; Nam, Sang Hee; Park, Hyeong Wook; Kim, Shin Wook; Shin, Hun Joo; Lee, Jae Choon; Kim, Ji Na; Park, Sung Kwang; Kim, Jin Young; Kang, Young-Nam

    2015-01-01

    The purpose of this study is to evaluate the clinical usefulness of modulated arc (mARC) treatment techniques. The mARC treatment plans of the non-small cell lung cancer (NSCLC) patients were performed in order to verify the clinical usefulness of mARC. A pre study was conducted to find the most competent plan condition of mARC treatment and the usefulness of mARC treatment plan was evaluated by comparing it with the other Arc treatment plans such as Tomotherapy and RapidArc. In the case of mARC, the optimal condition for the mARC plan was determined by comparing the dosimetric performance of the mARC plans with the use of various parameters. The various parameters includes the photon energies (6 MV, 10 MV), optimization point angle (6{\\deg}-10{\\deg} intervals), and total segment number (36-59 segment). The best dosimetric performance of mARC was observed at 10 MV photon energy and the point angle 6 degree, and 59 segments. The each treatment plans of three different techniques were compared with the followin...

  9. Investigation of diffuse current in arc boundary by electric probes

    Czech Academy of Sciences Publication Activity Database

    Chumak, Oleksiy; Hrabovský, Milan; Kavka, Tetyana; Kopecký, Vladimír

    Brno, 2005, s. 36-39. ISBN 80-214-2931-3. [Symposium on Physics of Switching Arc/16th./. Brno (CZ), 05.09.2005-09.09.2005] Institutional research plan: CEZ:AV0Z20430508 Keywords : arc boundary * anode attachment * arc root Subject RIV: BL - Plasma and Gas Discharge Physics

  10. Process characteristics of fibre-laser-assisted plasma arc welding

    Energy Technology Data Exchange (ETDEWEB)

    Mahrle, A; Schnick, M; Rose, S; Demuth, C; Beyer, E; Fuessel, U, E-mail: achim.mahrle@iws.fraunhofer.de [Dresden University of Technology, Institute of Surface and Manufacturing Technology, PO Box, D-01062 Dresden (Germany)

    2011-08-31

    Experimental and theoretical investigations on fibre-laser-assisted plasma arc welding (LAPW) were performed. Welding experiments were carried out on aluminium and steel sheets. In the case of a highly focused laser beam and a separate arrangement of plasma torch and laser beam, high-speed video recordings of the plasma arc and corresponding measurements of the time-dependent arc voltage revealed differences in the process behaviour for both materials. In the case of aluminium welding, a sharp decline in arc voltage and stabilization and guiding of the anodic arc root was observed whereas in steel welding the arc voltage was slightly increased after the laser beam was switched on. However, significant improvement of the melting efficiency with the combined action of plasma arc and laser beam was achieved for both types of material. Theoretical results of additional numerical simulations of the arc behaviour suggest that the properties of the arc plasma are mainly influenced not by a direct interaction with the laser radiation but by the laser-induced evaporation of metal. Arc stabilization with increased current densities is predicted for moderate rates of evaporated metal only whereas metal vapour rates above a certain threshold causes a destabilization of the arc and reduced current densities along the arc axis.

  11. Process characteristics of fibre-laser-assisted plasma arc welding

    Science.gov (United States)

    Mahrle, A.; Schnick, M.; Rose, S.; Demuth, C.; Beyer, E.; Füssel, U.

    2011-08-01

    Experimental and theoretical investigations on fibre-laser-assisted plasma arc welding (LAPW) were performed. Welding experiments were carried out on aluminium and steel sheets. In the case of a highly focused laser beam and a separate arrangement of plasma torch and laser beam, high-speed video recordings of the plasma arc and corresponding measurements of the time-dependent arc voltage revealed differences in the process behaviour for both materials. In the case of aluminium welding, a sharp decline in arc voltage and stabilization and guiding of the anodic arc root was observed whereas in steel welding the arc voltage was slightly increased after the laser beam was switched on. However, significant improvement of the melting efficiency with the combined action of plasma arc and laser beam was achieved for both types of material. Theoretical results of additional numerical simulations of the arc behaviour suggest that the properties of the arc plasma are mainly influenced not by a direct interaction with the laser radiation but by the laser-induced evaporation of metal. Arc stabilization with increased current densities is predicted for moderate rates of evaporated metal only whereas metal vapour rates above a certain threshold causes a destabilization of the arc and reduced current densities along the arc axis.

  12. Process characteristics of fibre-laser-assisted plasma arc welding

    International Nuclear Information System (INIS)

    Experimental and theoretical investigations on fibre-laser-assisted plasma arc welding (LAPW) were performed. Welding experiments were carried out on aluminium and steel sheets. In the case of a highly focused laser beam and a separate arrangement of plasma torch and laser beam, high-speed video recordings of the plasma arc and corresponding measurements of the time-dependent arc voltage revealed differences in the process behaviour for both materials. In the case of aluminium welding, a sharp decline in arc voltage and stabilization and guiding of the anodic arc root was observed whereas in steel welding the arc voltage was slightly increased after the laser beam was switched on. However, significant improvement of the melting efficiency with the combined action of plasma arc and laser beam was achieved for both types of material. Theoretical results of additional numerical simulations of the arc behaviour suggest that the properties of the arc plasma are mainly influenced not by a direct interaction with the laser radiation but by the laser-induced evaporation of metal. Arc stabilization with increased current densities is predicted for moderate rates of evaporated metal only whereas metal vapour rates above a certain threshold causes a destabilization of the arc and reduced current densities along the arc axis.

  13. Single Arc VMAT of H&N patients

    DEFF Research Database (Denmark)

    Bertelsen, Anders; Hansen, Christian Rønn; Johansen, Jørgen;

    2009-01-01

      Background: A few planning systems are currently able to plan volumetric modulated arc therapy (VMAT) which can be delivered on Elekta and Varian accelerators. Pinnacles version of a VMAT algorithm is called SmartArc. SmartArcs capability to modulate complicated treatment plans is to be tested...

  14. Single Arc VMAT of H&N patients

    DEFF Research Database (Denmark)

    Bertelsen, Anders; Hansen, Christian Rønn; Johansen, Jørgen;

      Background: A few planning systems are currently able to plan volumetric modulated arc therapy (VMAT) which can be delivered on Elekta and Varian accelerators. Pinnacles version of a VMAT algorithm is called SmartArc. SmartArcs capability to modulate complicated treatment plans is to be tested...

  15. The Plio Quaternary Ambon arc, Eastern Indonesia

    Science.gov (United States)

    Honthaas, Christian; Maury, René C.; Priadi, Bambang; Bellon, Hervé; Cotten, Joseph

    1999-01-01

    Plio-Quaternary lavas and granites have been collected from Ambon, Seram, Kelang, Haruku, Saparua, Ambelau and Banda Api islands, Eastern Indonesia. They include low-K calc-alkaline basalts, andesites, dacites and rhyolites and high-K calc-alkaline andesites, dacites, rhyolites and granites. All these rocks present the usual chemical characteristics of island-arc magmas. The high-K suite of Ambon is mostly represented by cordierite-bearing dacites (known as ambonites) and granites. Low-K and high-K magmas were emplaced in neighbouring islands or even in the same island (Ambon), often concomitantly, during two magmatic pulses at 5-3.2 Ma and 2.3-1 Ma, respectively. We propose that the low-K suite results from the evolution of basaltic magmas derived from mantle melting above the Western Irian Jaya plate which subducts along the Seram trough. Intermediate and acidic rocks of the high-K suite (e.g. ambonites) are thought to derive from low-K mafic magmas through massive assimilation of the Seram-Ambon continental crust, as originally proposed by Van Bemmelen in 1949. The timing of magmatic events and the geochemical features of the studied lavas are clearly different from those of the southern part of the Banda arc, in which the low-K suite is lacking. In agreement with earlier seismic evidence for two different slabs subducting beneath the Seram-Ambon continental block and beneath the southern Banda arc (from Wetar to Manuk), respectively, we propose to recognise a new Plio-Quaternary island arc, i.e. the Ambon arc, extending west-east from Ambelau to the Banda Archipelago active low-K volcanoes through Kelang, southwestern Seram, Ambon, Haruku and Saparua.

  16. Radiation of long and high power arcs

    Science.gov (United States)

    Cressault, Y.; Bauchire, J. M.; Hong, D.; Rabat, H.; Riquel, G.; Sanchez, F.; Gleizes, A.

    2015-10-01

    The operators working on electrical installations of low, medium and high voltages can be accidentally exposed to short-circuit arcs ranging from a few kA to several tens of kA. To protect them from radiation, according to the exposure limits, we need to characterize the radiation emitted by the powerful arc. Therefore, we have developed a general experimental and numerical study in order to estimate the spectral irradiance received at a given distance from the arc. The experimental part was based on a very long arc (up to 2 m) with high ac current (between 4 and 40 kA rms, duration 100 ms) using 3 kinds of metallic contacts (copper, steel and aluminium). We measured the irradiance received 10m from the axis of the arc, and integrated on 4 spectral intervals corresponding to the UV, visible, IRA  +  B and IRC. The theoretical part consisted of calculating the radiance of isothermal plasmas in mixtures of air and metal vapour, integrated over the same spectral intervals as defined in the experiments. The comparison between the theoretical and experimental results has allowed the defining of three isothermal radiation sources whose combination leads to a spectral irradiation equivalent to the experimental one. Then the calculation allowed the deduction of the spectral description of the irradiance over all the wavelength range, between 200 nm and 20 μm. The final results indicate that the influence of metal is important in the visible and UVA ranges whereas the IR radiation is due to the air plasma and surrounding hot gas and fumes.

  17. Geochemical studies on island arc volcanoes

    International Nuclear Information System (INIS)

    This paper summarizes advances in three topics of geochemical studies on island arc volcanoes, which I and my colleagues have been investigating. First one is strontium isotope studies of arc volcanic rocks mainly from Japanese island arcs. We have shown that the precise spatial distribution of the 87Sr/86Sr ratio reflects natures of the subduction structure and slab-mantle interaction. Based on the 87Sr/86Sr ratio of volcanic rocks in the northern Kanto district, where two plates subduct concurrently with different directions, the existence of an aseismic portion of the Philippine Sea plate ahead of the seismic one was suggested. Second one is geochemical monitoring of active arc volcanoes. 3He/4He ratio of volcanic volatiles was shown to be a good indicator to monitor the behavior of magma: ascent and drain-back of magma result in increase and decrease in the ratio, respectively. In the case of 1986 eruptions of Izu-Oshima volcano, the ratio began to increase two months after big eruptions, reaching the maximum and decreased. Such delayed response is explained in terms of travelling time of magmatic helium from the vent area to the observation site along the underground steam flow. Third one is remote observation of volcanic gas chemistry of arc volcanoes, using an infrared absorption spectroscopy. During Unzen eruptions starting in 1990, absorption features of SO2 and HCl of volcanic gas were detected from the observation station at 1.3 km distance. This was the first ground-based remote detection of HCl in volcanic gas. In the recent work at Aso volcano, we could identify 5 species (CO, COS, CO2, SO2 and HCl) simultaneously in the volcanic plume spectra. (author)

  18. Failure to thrive.

    Science.gov (United States)

    Nangia, Sushma; Tiwari, Soumya

    2013-07-01

    Failure to thrive is poor physical growth that results when the nutritional demands of young children are not fulfilled. This diagnosis is made when, on serial growth monitoring, the child's anthropometric parameters such as weight for age and/or height are found to be significantly below the expected values. A detailed evaluation by the treating physician, taking into account physical and psychosocial factors affecting the child's health is essential for understanding the factors contributing to failure to thrive. The treatment of this entity requires a multidisciplinary approach, correcting the macro and micronutrient deficiency in the child as well as education of parents regarding age-appropriate feeding recommendation for children. In addition, parents need to be apprised of the possible implications of malnutrition on growth and neurodevelopment of the child. Early childhood being a crucial period for growth and development, an early diagnosis and treatment will result in better outcomes in children with failure to thrive. PMID:23604606

  19. [Hypoxic lung failure].

    Science.gov (United States)

    David, S; Wiesner, O

    2016-04-01

    Hypoxic lung failure is among the major indications for patients' referral to intensive care units either for surveillance or if necessary therapy. There are a vast number of pathophysiological causes of lung failure and the optimal treatment highly depends on the underlying pathology; therefore, no standard algorithm exists. So-called acute respiratory distress syndrome (ARDS) represents a very severe manifestation of hypoxemic lung failure that is of particular relevance for intensivists and is therefore the focus of this review. In addition to fundamental pathophysiology of lung injury, the article also focuses on established and modern treatment strategies. Moreover, we will briefly highlight innovative concepts of ARDS treatment that might become relevant in the future. PMID:27084180

  20. Reported tailings dam failures

    Energy Technology Data Exchange (ETDEWEB)

    Rico, M. [CSIC - Instituto Pirenaico de Ecologia, Zaragoza (Spain)], E-mail: mayterico@ipe.csic.es; Benito, G. [CSIC - Centro de Ciencias Medioambientales, Madrid (Spain); Salgueiro, A.R. [CERENA - Centro de Recursos Naturais e Ambiente of IST, Lisboa (Portugal); Diez-Herrero, A. [Geological Hazards Unit, Spanish Geological Survey (IGME), Madrid (Spain); Pereira, H.G. [CERENA - Centro de Recursos Naturais e Ambiente of IST, Lisboa (Portugal)

    2008-04-01

    A detailed search and re-evaluation of the known historical cases of tailings dam failure was carried out. A corpus of 147 cases of worldwide tailings dam disasters, from which 26 located in Europe, was compiled in a database. This contains six sections, including dam location, its physical and constructive characteristics, actual and putative failure cause, sludge hydrodynamics, socio-economical consequences and environmental impacts. Europe ranks in second place in reported accidents (18%), more than one third of them in dams 10-20 m high. In Europe, the most common cause of failure is related to unusual rain, whereas there is a lack of occurrences associated with seismic liquefaction, which is the second cause of tailings dam breakage elsewhere in the world. Moreover, over 90% of incidents occurred in active mines, and only 10% refer to abandoned ponds. The results reached by this preliminary analysis show an urgent need for EU regulations regarding technical standards of tailings disposal.

  1. Reported tailings dam failures

    International Nuclear Information System (INIS)

    A detailed search and re-evaluation of the known historical cases of tailings dam failure was carried out. A corpus of 147 cases of worldwide tailings dam disasters, from which 26 located in Europe, was compiled in a database. This contains six sections, including dam location, its physical and constructive characteristics, actual and putative failure cause, sludge hydrodynamics, socio-economical consequences and environmental impacts. Europe ranks in second place in reported accidents (18%), more than one third of them in dams 10-20 m high. In Europe, the most common cause of failure is related to unusual rain, whereas there is a lack of occurrences associated with seismic liquefaction, which is the second cause of tailings dam breakage elsewhere in the world. Moreover, over 90% of incidents occurred in active mines, and only 10% refer to abandoned ponds. The results reached by this preliminary analysis show an urgent need for EU regulations regarding technical standards of tailings disposal

  2. Numerical investigation of the double-arcing phenomenon in a cutting arc torch

    Energy Technology Data Exchange (ETDEWEB)

    Mancinelli, B. R., E-mail: bmancinelli@frvt.utn.edu.ar [Grupo de Descargas Eléctricas, Departamento Ingeniería Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651 (2600) Venado Tuerto, Santa Fe (Argentina); Minotti, F. O.; Kelly, H. [Grupo de Descargas Eléctricas, Departamento Ingeniería Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651 (2600) Venado Tuerto, Santa Fe (Argentina); Instituto de Física del Plasma (CONICET), Departamento de Física, Facultad de Ciencias Exactas y Naturales (UBA) Ciudad Universitaria Pab. I, 1428 Buenos Aires (Argentina); Prevosto, L. [Instituto de Física del Plasma (CONICET), Departamento de Física, Facultad de Ciencias Exactas y Naturales (UBA) Ciudad Universitaria Pab. I, 1428 Buenos Aires (Argentina)

    2014-07-14

    A numerical investigation of the double-arcing phenomenon in a cutting arc torch is reported. The dynamics of the double-arcing were simulated by using a two-dimensional model of the gas breakdown development in the space-charge layer contiguous to the nozzle of a cutting arc torch operated with oxygen. The kinetic scheme includes ionization of heavy particles by electron impact, electron attachment, electron detachment, electron–ion recombination, and ion–ion recombination. Complementary measurements during double-arcing phenomena were also conducted. A marked rise of the nozzle voltage was found. The numerical results showed that the dynamics of a cathode spot at the exit of the nozzle inner surface play a key role in the raising of the nozzle voltage, which in turn allows more electrons to return to the wall at the nozzle inlet. The return flow of electrons thus closes the current loop of the double-arcing. The increase in the (floating) nozzle voltage is due to the fact that the increased electron emission at the spot is mainly compensated by the displacement current (the ions do not play a relevant role due to its low-mobility) until that the stationary state is achieved and the electron return flow fully-compensates the electron emission at the spot. A fairly good agreement was found between the model and the experiment for a spot emission current growth rate of the order of 7 × 10{sup 4} A/s.

  3. Numerical investigation of the double-arcing phenomenon in a cutting arc torch

    International Nuclear Information System (INIS)

    A numerical investigation of the double-arcing phenomenon in a cutting arc torch is reported. The dynamics of the double-arcing were simulated by using a two-dimensional model of the gas breakdown development in the space-charge layer contiguous to the nozzle of a cutting arc torch operated with oxygen. The kinetic scheme includes ionization of heavy particles by electron impact, electron attachment, electron detachment, electron–ion recombination, and ion–ion recombination. Complementary measurements during double-arcing phenomena were also conducted. A marked rise of the nozzle voltage was found. The numerical results showed that the dynamics of a cathode spot at the exit of the nozzle inner surface play a key role in the raising of the nozzle voltage, which in turn allows more electrons to return to the wall at the nozzle inlet. The return flow of electrons thus closes the current loop of the double-arcing. The increase in the (floating) nozzle voltage is due to the fact that the increased electron emission at the spot is mainly compensated by the displacement current (the ions do not play a relevant role due to its low-mobility) until that the stationary state is achieved and the electron return flow fully-compensates the electron emission at the spot. A fairly good agreement was found between the model and the experiment for a spot emission current growth rate of the order of 7 × 104 A/s.

  4. The investigation of carbon nitride films prepared at various arc currents by vacuum cathode arc method

    International Nuclear Information System (INIS)

    The carbon nitride films have been prepared in the arc currents range of 20-60 A at the Ar/N2 atmosphere of 50/400 sccm by the vacuum cathode arc deposition method. The properties of the films were characterized by x-ray photoelectron spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy and nanoindentation. The N concentration showed a maximum of 35 at% at 20 A and decreased gradually with the arc currents. The films below 40 A consisted of linear polymeric-like component and sp2 graphitic cluster. With the increasing of the arc current from 20 to 40 A, the ID/IG rose and the photoluminescence (PL) fell gradually, which resulted from the development of the sp2 graphitic phase and the decrease of the polymeric-like phase. As a result, the CC bonds increased and sp3CN and sp2CN decreased. Above 40 A, with the increasing of arc currents, ID/IG fell and the PL increased gradually, which reflected the decreasing of sp2 graphitic phase and the modification of C and N atoms in sp2 cluster. The CC bonds and sp3CN fell and the sp2CN rose. The nanohardness of films showed increasing tendency with the arc currents. The variation of the relative ratio and the average energy of N-containing species and C-containing species at the atmosphere would be responsible for the change in the properties of films. (author)

  5. Modeling Epidemic Network Failures

    DEFF Research Database (Denmark)

    Ruepp, Sarah Renée; Fagertun, Anna Manolova

    2013-01-01

    This paper presents the implementation of a failure propagation model for transport networks when multiple failures occur resulting in an epidemic. We model the Susceptible Infected Disabled (SID) epidemic model and validate it by comparing it to analytical solutions. Furthermore, we evaluate...... the SID model’s behavior and impact on the network performance, as well as the severity of the infection spreading. The simulations are carried out in OPNET Modeler. The model provides an important input to epidemic connection recovery mechanisms, and can due to its flexibility and versatility be used...... to evaluate multiple epidemic scenarios in various network types....

  6. New product failure

    DEFF Research Database (Denmark)

    Dijksterhuis, Garmt Bernard

    2016-01-01

    When new consumer products are developed and later launched, 50 to 75 percent of them are removed from the market far short of meeting their projected financial targets. In short: they fail. We conclude that this failure is due to institutionalized insufficiencies in the use of the sciences that...... research surroundings. This often is in great contrast with their high levels of technological science, paralleled by their respective research budgets. In this paper we present five problem areas that may contribute to this mismatch, contributing to needlessly high numbers of product failures. We have...

  7. Generalized Block Failure

    DEFF Research Database (Denmark)

    Jönsson, Jeppe

    2015-01-01

    shows that no readily available tests with a well-defined substantial eccentricity have been performed. This paper presents theoretical and experimental work leading towards generalized block failure capacity methods. Simple combination of normal force, shear force and moment stress distributions along......Block tearing is considered in several codes as a pure block tension or a pure block shear failure mechanism. However in many situations the load acts eccentrically and involves the transfer of a substantial moment in combination with the shear force and perhaps a normal force. A literature study...... yield lines around the block leads to simple interaction formulas similar to other interaction formulas in the codes....

  8. Failure detection and evaluation

    International Nuclear Information System (INIS)

    The objective of failure/damage analysis and documentation (which should be as condensed as possible and as comprehensive as needed) is to limit the extent of damage and failures and to allow experience gained from them to be incorporated in the design of new plants and systems or in the specifications of plants and systems already in operation. Data collection is no longer bottle-necked by today's EDP potential. The importance of damage surveys and analyses and their evaluation originated in the need to provide data material for implementing risk analyses for nuclear installations. Damage evaluation is discussed by means of an expample. (orig./GL)

  9. Narrative attributions of entrepreneurial failure

    OpenAIRE

    Mantere, Saku; Aula, Pekka; Schildt, Henri; Vaara, Eero

    2013-01-01

    We examine how organizational stakeholders use narratives in their psychological processing of venture failure. We identify a range of “narrative attributions”, alternative accounts of failure that actors draw on to process the failure and their role in it. Our analysis provides a view of entrepreneurial failure as a complex social construction, as entrepreneurs, hired executives, employees and the media construct failure in distinctively different ways. Narratives provide means for both ...

  10. Driven Motion and Instability of an Atmospheric Pressure Arc

    International Nuclear Information System (INIS)

    Atmospheric pressure arcs are used extensively in applications such as welding and metallurgy. However, comparatively little is known of the physics of such arcs in external magnetic fields and the mechanisms of the instabilities present. In order to address questions of equilibrium and stability of such arcs, an experimental arc furnace is constructed and operated in air with graphite cathode and steel anode at currents 100-250 A. The arc is diagnosed with a gated intensified camera and a collimated photodiode array, as well as fast voltage and current probes

  11. Driven Motion and Instability of an Atmospheric Pressure Arc

    Energy Technology Data Exchange (ETDEWEB)

    Max Karasik

    1999-12-01

    Atmospheric pressure arcs are used extensively in applications such as welding and metallurgy. However, comparatively little is known of the physics of such arcs in external magnetic fields and the mechanisms of the instabilities present. In order to address questions of equilibrium and stability of such arcs, an experimental arc furnace is constructed and operated in air with graphite cathode and steel anode at currents 100-250 A. The arc is diagnosed with a gated intensified camera and a collimated photodiode array, as well as fast voltage and current probes.

  12. Perioperative acute renal failure.

    LENUS (Irish Health Repository)

    Mahon, Padraig

    2012-02-03

    PURPOSE OF REVIEW: Recent biochemical evidence increasingly implicates inflammatory mechanisms as precipitants of acute renal failure. In this review, we detail some of these pathways together with potential new therapeutic targets. RECENT FINDINGS: Neutrophil gelatinase-associated lipocalin appears to be a sensitive, specific and reliable biomarker of renal injury, which may be predictive of renal outcome in the perioperative setting. For estimation of glomerular filtration rate, cystatin C is superior to creatinine. No drug is definitively effective at preventing postoperative renal failure. Clinical trials of fenoldopam and atrial natriuretic peptide are, at best, equivocal. As with pharmacological preconditioning of the heart, volatile anaesthetic agents appear to offer a protective effect to the subsequently ischaemic kidney. SUMMARY: Although a greatly improved understanding of the pathophysiology of acute renal failure has offered even more therapeutic targets, the maintenance of intravascular euvolaemia and perfusion pressure is most effective at preventing new postoperative acute renal failure. In the future, strategies targeting renal regeneration after injury will use bone marrow-derived stem cells and growth factors such as insulin-like growth factor-1.

  13. Failure in Education

    Science.gov (United States)

    Carpenter, Peter

    2009-01-01

    In this article, it is argued that Kurt Hahn felt that it was important for children to experience 'failure' at times and to learn how to cope with it. If this is no longer desirable in the classroom, it ought to be possible to encourage children to be adventurous and "take risks" in a wide range of Outward Bound activities.

  14. Poverty and Aspirations Failure

    NARCIS (Netherlands)

    Dalton, P.S.; Ghosal, S.; Mani, A.

    2011-01-01

    We develop a theoretical framework to study the psychology of poverty and 'aspirations failure'. In our framework, the rich and the poor share the same preferences - and also a behavioral bias in setting aspirations. Greater downside risks imposed by poverty exacerbates the effects of this behaviora

  15. Poverty and aspirations failure

    NARCIS (Netherlands)

    Dalton, P.S.; Ghosal, S.; Mani, A.

    2016-01-01

    We develop a theoretical framework to study the psychology of poverty and ‘aspirations failure’, defined as the failure to aspire to one’s own potential. In our framework, rich and the poor persons share the same preferences and same behavioral bias in setting aspirations. We show that poverty can e

  16. Dual Torch Plasma Arc Furnace for Medical Waste Treatment

    Institute of Scientific and Technical Information of China (English)

    LIU Bin; M.KIKUCHI; LI Heping; T.IWAO; T.INABA

    2007-01-01

    In this paper,characteristics of a dual torch plasma arc used for hazardous waste treatment and operated at atmospheric pressure are studied,and also compared with those of the multi-torch plasma arc and the single torch plasma arc.The dual torch plasma arc is generated between the cathode and anode with argon as the working gas.The temperature distributions of the plasma arc are measured using a spectroscope and line pair method with the assumption of local thermodynamic equilibrium (LTE) for the DC arc current I = 100 A and argon flow rate Q = 15 slpm.The measurements show that the temperatures of the dual torch arc plasma in the regions near the cathode,the anode and the center point are 10,000 K,11,000 K and 9,000 K,respectively.And the high temperature region of the multi torch plasma arc is of double or much wider size than that of a conventional dual torch plasma arc and single plasma torch.Based on the preceding studies,a dual torch plasma arc furnace is developed in this study.The measured gas temperature at the center region of the argon arc is about 11,000 K for the case of I = 200 A and Q = 30 slpm operated in atmosphere.

  17. NTWV-based sensing keyhole dimension in plasma arc welding

    Institute of Scientific and Technical Information of China (English)

    Jia Chuanbao; Wu Chuansong; Zhang Yuming

    2008-01-01

    During stable keyhole plasma arc welding, the pilot arc and the transferred arc exist at the meantime, and the arcs can be considered as a composition of two parts inside and outside the nozzle, respectively. Under the mechanical constriction and thermal contraction effects, the inside arc has certain arc length, electron density and arc profile etc. Inducing constant tungsten-to-nozzle voltage. However, the arc outside the nozzle diverges at about 5 degrees and has certain characteristics similar to the free arcs. The nozzle-to-workpiece voltage (NTWV) depends mainly on the length of the arc, which gets bigger as increasing of the weld penetration and keyhole size. The NTWV sensor is developed for monitoring NTWV in real time. The welding experiments are designed to get different penetrations and keyhole sizes. It is found that as the weld penetration and the keyhole size increase, NTWV also increases linearly. The NTWV signals can be used as the feedback variable in automatic control of keyhole plasma arc welding.

  18. Discharge Characteristics of DC Arc Water Plasma for Environmental Applications

    Institute of Scientific and Technical Information of China (English)

    LI Tianming; Sooseok CHOI; Takayuki WATANABE

    2012-01-01

    A water plasma was generated by DC arc discharge with a hafnium embedded rodtype cathode and a nozzle-type anode. The discharge characteristics were examined by changing the operation parameter of the arc current. The dynamic behavior of the arc discharge led to significant fluctuations in the arc voltage and its frequency. Analyses of the high speed image and the arc voltage waveform showed that the arc discharge was in the restrike mode and its frequency varied within several tens of kilohertz according to the operating conditions. The larger thermal plasma volume was generated by the higher flow from the forming steam with a higher restrike frequency in the higher arc current conditions. In addition, the characteristics of the water plasma jet were investigated by means of optical emission spectroscopy to identify the abundant radicals required in an efficient waste treatment process.

  19. The African Health Profession Regulatory Collaborative (ARC) at two years

    Science.gov (United States)

    McCarthy, Carey F; Zuber, Alexandra; Kelley, Maureen A; Verani, Andre R; Riley, Patricia L

    2016-01-01

    Background The African Health Profession Regulatory Collaborative (ARC) for nurses and midwives was created in response to the increasing reliance on shifting HIV tasks to nurses and midwives without the necessary regulation supporting this enhanced professional role. ARC Approach The ARC initiative comprises regional meetings, technical assistance, and regulatory improvement grants which enhance HIV service delivery by nurses and midwives, and systematic evaluation of project impact. Results Eight of 11 countries funded by ARC advanced a full stage in regulatory capacity during their 1-year project period. Countries in ARC also demonstrated increased capacity in project management and proposal writing. Discussion The progress of country teams thus far suggests ARC is a successful model for regulation strengthening and capacity building, as well as presenting a novel approach for sustainability and country ownership. The ARC platform has been a successful vehicle for regional harmonisation of updated regulations and promises to help facilitate the enhancement of HIV service delivery by nurses and midwives. PMID:27066113

  20. ARC/SPAR sealing system - Preliminary field evaluation

    International Nuclear Information System (INIS)

    The ARC/SPAR sealing system, based on an ultra-sonic signature and designed for sealing CANDU-type spent fuel, has been undergoing field evaluation at Gentilly-2 600 MW Reactor for the last ten months. The test was designed to evaluate the hardware and software of the system, the effort required for the application and verification of the containment and seals, the interference with operator, the procedures and the false- and missed alarm rates. Routine use conditions were emphasized throughout the test. In the course of the trial the entire content of the spent fuel in the pond was sealed. Preliminary results indicate that the system is acceptable. Hardware, software and procedures except for the transducer worked well. Transducer failure occurred too frequently at an unacceptable rate. The problem was identified and will hopefully be overcome. Level of intrusion with operations could be considered acceptable. Inspectors carrying out seal application and verification were adequately trained and performed satisfactorily. Auto- and crosscorrelations are reported. Recommendations are made for the improvement of equipment and procedures. The test will continue until the end of this year

  1. Media effects on nanobrass arc fabrications

    International Nuclear Information System (INIS)

    Brass rods (3 mm x 30 mm) are directly converted into brass nanoparticles through a modified arc method, at 100 A, and in five different media. The X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM) data show strong dependence of nanoparticle sizes and their compositions on the media employed. In distilled water, both nanobrass (30 nm) and nano-Cu/ZnO (18 nm) are produced in comparable quantities. In gaseous nitrogen merely nanobrass (49 nm) is observed, in a high yield. In contrast, a very low yield of nanoproduct(s) is encountered in liquid nitrogen. In the open air, nanobrass (75 nm) is formed along with traces of ZnO. In ethylene glycol, nanobrass (108 nm) is formed as the major product along with a nanoalloy of CuZn5 (25 nm). Among these, distilled water proved to be the medium of choice for the arc synthesis of nanobrass

  2. The singing arc: the oldest memristor?

    CERN Document Server

    Ginoux, Jean-Marc

    2014-01-01

    On April 30th 2008, the journal Nature announced that the missing circuit element, postulated thirty-seven years before by Professor Leon O. Chua has been found. Thus, after the capacitor, the resistor and the inductor, the existence of a fourth fundamental element of electronic circuits called "memristor" was established. In order to point out the importance of such a discovery, the aim of this article is first to propose an overview of the manner with which the three others have been invented during the past centuries. Then, a comparison between the main properties of the singing arc, i.e. a forerunner device of the triode used in Wireless Telegraphy, and that of the memristor will enable to state that the singing arc could be considered as the oldest memristor.

  3. Electrical Safety and Arc Flash Protections

    Energy Technology Data Exchange (ETDEWEB)

    R. Camp

    2008-03-04

    Over the past four years, the Electrical Safety Program at PPPL has evolved in addressing changing regulatory requirements and lessons learned from accident events, particularly in regards to arc flash hazards and implementing NFPA 70E requirements. This presentation will discuss PPPL's approaches to the areas of electrical hazards evaluation, both shock and arc flash; engineered solutions for hazards mitigation such as remote racking of medium voltage breakers, operational changes for hazards avoidance, targeted personnel training and hazard appropriate personal protective equipment. Practical solutions for nominal voltage identification and zero voltage checks for lockout/tagout will also be covered. Finally, we will review the value of a comprehensive electrical drawing program, employee attitudes expressed as a personal safety work ethic, integrated safety management, and sustained management support for continuous safety improvement.

  4. High velocity pulsed wire-arc spray

    Science.gov (United States)

    Witherspoon, F. Douglas (Inventor); Massey, Dennis W. (Inventor); Kincaid, Russell W. (Inventor)

    1999-01-01

    Wire arc spraying using repetitively pulsed, high temperature gas jets, usually referred to as plasma jets, and generated by capillary discharges, substantially increases the velocity of atomized and entrained molten droplets. The quality of coatings produced is improved by increasing the velocity with which coating particles impact the coated surface. The effectiveness of wire-arc spraying is improved by replacing the usual atomizing air stream with a rapidly pulsed high velocity plasma jet. Pulsed power provides higher coating particle velocities leading to improved coatings. 50 micron aluminum droplets with velocities of 1500 m/s are produced. Pulsed plasma jet spraying provides the means to coat the insides of pipes, tubes, and engine block cylinders with very high velocity droplet impact.

  5. Arc inhibitors for lower hybrid waveguide arrays

    International Nuclear Information System (INIS)

    The discontinuity at the mouth of a phased array between waveguide fields and plasma fields gives rise to strong, localized electric fields at the septa, especially if the array is excited asymetrically. Methods are suggested for modifying these fields to reduce the possibility of arcing. Probe measurements of the fields near the septa show that small but significant reductions of the local fields are possible and might raise the maximum power handling capability of an array

  6. Adaptive Gas Metal Arc (GMA) Welder

    Science.gov (United States)

    Nachev, G.; Petkov, B.; Blagoev, L.; Tsankarski, I.

    1984-02-01

    Unlike NC machine-tools, where the tool path is primary and the product shape results from it, in arc welding the product is primary, and the welder - human or robot - has to contend with poor fitups, bad preparations, inexact positionning etc. All this means one thing - adaptivity. The axtent to which this is reasonable is discussed, and then a research project, conducted at IICR with the aim to create an adaptive GMA robot, is presented.

  7. POWDER DENSIFICATION IN A TRANSFERRED ARC REACTOR

    OpenAIRE

    Denoirjean, A.; Vardelle, A.; Grimaud, A; Fauchais, P.

    1990-01-01

    To improve the plasma spraying of porous zirconia particles prepared by spray drying, a pre-treatment of powder has been carried out in a transferred arc plasma. The densification of the agglomeraed particles must raise the resistance of agglomerated particles against mechanical and thermal loads during plasma spraying. Before and after treatment, powders are characterized with regard to morphology, grain size distribution, density, phase composition and mechanical resistance. With the plasma...

  8. Exploiting robots in arc welded fabrication

    International Nuclear Information System (INIS)

    This book explores the use of robots for industrial arc welding applications. A number of important issues, such as safety and economics are addressed. A wide range of industrial installation applications are described including production line chassis welding with multiple robots. The use of vision based sensor systems is explained to provide data on joint location and joint volume. Other areas covered include flexible manufacturing systems, computer integrated manufacture and design problems. The book concludes with a review of future trends. (UK)

  9. Multi-colour detection of gravitational arcs

    Science.gov (United States)

    Maturi, Matteo; Mizera, Sebastian; Seidel, Gregor

    2014-07-01

    Strong gravitational lensing provides fundamental insights into the understanding of the dark matter distribution in massive galaxies, galaxy clusters, and the background cosmology. Despite their importance, few gravitational arcs have been discovered so far. The urge for more complete, large samples and unbiased methods of selecting candidates increases. Several methods for the automatic detection of arcs have been proposed in the literature, but large amounts of spurious detections retrieved by these methods force observers to visually inspect thousands of candidates per square degree to clean the samples. This approach is largely subjective and requires a huge amount of checking by eye, especially considering the actual and upcoming wide-field surveys, which will cover thousands of square degrees. In this paper we study the statistical properties of the colours of gravitational arcs detected in the 37 deg2 of the CFHTLS-Archive-Research Survey (CARS). Most of them lie in a relatively small region of the (g' - r', r' - i') colour-colour diagram. To explain this property, we provide a model that includes the lensing optical depth expected in a ΛCDM cosmology that, in combination with the sources' redshift distribution of a given survey, in our case CARS, peaks for sources at redshift z ~ 1. By furthermore modelling the colours derived from the spectral energy distribution of the galaxies that dominate the population at that redshift, the model reproduces the observed colours well. By taking advantage of the colour selection suggested by both data and model, we automatically detected 24 objects out of 90 detected by eye checking. Compared with the single-band arcfinder, this multi-band filtering returns a sample complete to 83% and a contamination reduced by a factor of ~6.5. New gravitational arc candidates are also proposed.

  10. HPF Implementation of ARC3D

    Science.gov (United States)

    Frumkin, Michael; Yan, Jerry

    1999-01-01

    We present an HPF (High Performance Fortran) implementation of ARC3D code along with the profiling and performance data on SGI Origin 2000. Advantages and limitations of HPF as a parallel programming language for CFD applications are discussed. For achieving good performance results we used the data distributions optimized for implementation of implicit and explicit operators of the solver and boundary conditions. We compare the results with MPI and directive based implementations.

  11. Maintaining Arc Consistency with Multiple Residues

    OpenAIRE

    Lecoutre, Christophe; Likitvivatanavong, Chavalit; Shannon, Scott; Yap, Roland; Zhang, Yuanlin

    2008-01-01

    International audience Exploiting residual supports (or residues) has proved to be one of the most cost-effective approaches for Maintaining Arc Consistency during search (MAC). While MAC based on optimal AC algorithm may have better theoretical time complexity in some cases, in practice the overhead for maintaining required data structure during search outweighs the benefit, not to mention themore complicated implementation. Implementing MAC with residues, on the other hand, is trivial. I...

  12. Optical diagnostics of a gliding arc

    DEFF Research Database (Denmark)

    Sun, Z.W.; Zhu, J.J.; Li, Z.S.;

    2013-01-01

    path triggered by Townsend breakdown between the two legs of the gliding arc. The emission from the plasma column is shown to pulsate at a frequency of 62.5 kHz, i.e., twice the frequency of the AC power supply. Optical emission spectra of the plasma radiation show the presence of excited N2, NO and OH......Dynamic processes in a gliding arc plasma generated between two diverging electrodes in ambient air driven by 31.25 kHz AC voltage were investigated using spatially and temporally resolved optical techniques. The life cycles of the gliding arc were tracked in fast movies using a high-speed camera...... with framing rates of tens to hundreds of kHz, showing details of ignition, motion, pulsation, short-cutting, and extinction of the plasma column. The ignition of a new discharge occurs before the extinction of the previous discharge. The developed, moving plasma column often short-cuts its current...

  13. Arc melter demonstration baseline test results

    Energy Technology Data Exchange (ETDEWEB)

    Soelberg, N.R.; Chambers, A.G.; Anderson, G.L.; Oden, L.L.; O`Connor, W.K.; Turner, P.C.

    1994-07-01

    This report describes the test results and evaluation for the Phase 1 (baseline) arc melter vitrification test series conducted for the Buried Waste Integrated Demonstration program (BWID). Phase 1 tests were conducted on surrogate mixtures of as-incinerated wastes and soil. Some buried wastes, soils, and stored wastes at the INEL and other DOE sites, are contaminated with transuranic (TRU) radionuclides and hazardous organics and metals. The high temperature environment in an electric arc furnace may be used to process these wastes to produce materials suitable for final disposal. An electric arc furnace system can treat heterogeneous wastes and contaminated soils by (a) dissolving and retaining TRU elements and selected toxic metals as oxides in the slag phase, (b) destroying organic materials by dissociation, pyrolyzation, and combustion, and (c) capturing separated volatilized metals in the offgas system for further treatment. Structural metals in the waste may be melted and tapped separately for recycle or disposal, or these metals may be oxidized and dissolved into the slag. The molten slag, after cooling, will provide a glass/ceramic final waste form that is homogeneous, highly nonleachable, and extremely durable. These features make this waste form suitable for immobilization of TRU radionuclides and toxic metals for geologic timeframes. Further, the volume of contaminated wastes and soils will be substantially reduced in the process.

  14. Arc melter demonstration baseline test results

    International Nuclear Information System (INIS)

    This report describes the test results and evaluation for the Phase 1 (baseline) arc melter vitrification test series conducted for the Buried Waste Integrated Demonstration program (BWID). Phase 1 tests were conducted on surrogate mixtures of as-incinerated wastes and soil. Some buried wastes, soils, and stored wastes at the INEL and other DOE sites, are contaminated with transuranic (TRU) radionuclides and hazardous organics and metals. The high temperature environment in an electric arc furnace may be used to process these wastes to produce materials suitable for final disposal. An electric arc furnace system can treat heterogeneous wastes and contaminated soils by (a) dissolving and retaining TRU elements and selected toxic metals as oxides in the slag phase, (b) destroying organic materials by dissociation, pyrolyzation, and combustion, and (c) capturing separated volatilized metals in the offgas system for further treatment. Structural metals in the waste may be melted and tapped separately for recycle or disposal, or these metals may be oxidized and dissolved into the slag. The molten slag, after cooling, will provide a glass/ceramic final waste form that is homogeneous, highly nonleachable, and extremely durable. These features make this waste form suitable for immobilization of TRU radionuclides and toxic metals for geologic timeframes. Further, the volume of contaminated wastes and soils will be substantially reduced in the process

  15. A unified model of transport phenomena in gas metal arc welding including electrode, arc plasma and molten pool

    International Nuclear Information System (INIS)

    This paper presents a theoretical model for describing globular transfer in gas metal arc welding. The heat and mass transfer in the electrode, arc plasma and molten pool are considered in one unified model. Using the volume of fluid method, the transport phenomena are dynamically studied in the following processes: droplet formation and detachment, droplet flight in arc plasma, impingement of droplets on the molten pool and solidification after the arc extinguishes. The simulation of heat and mass transfer in the arc plasma considers the developing surface profile of the electrode and molten pool and also the effect of the flying droplet inside the arc plasma. Furthermore, the heat inputs to the electrode and the molten pool result from the simulation of the arc plasma. In addition, a He-Ne laser in conjunction with the shadow-graphing technique is used to observe the metal-transfer process. The theoretical predictions and experimental results are shown to be in good agreement

  16. OBSTETRIC RENAL FAILURE

    Directory of Open Access Journals (Sweden)

    Rajeshwari

    2015-11-01

    Full Text Available Renal failure in obstetrics is rare but important complication, associated with significant mortality and long term morbidity.1,2 It includes acute renal failure due to obstetrical complications or due to deterioration of existing renal disease. AIMS AND OBJECTIVES: To evaluate the etiology and outcome of renal failure in obstetric patients. METHODS: We prospectively analyzed 30 pregnant and puerperal women with acute renal failure or pre-existing renal disease developing renal failure during pregnancy between November 2007 to sep-2009. Patients who presented/developed ARF during the hospital stay were included in this study. RESULTS: Among 30 patients, mean age was 23 years and 33 years age group. 12 cases (40% patients were primigravidae and 9(30% patients were multigravidae and 9 cases (30% presented in post-partum period. Eighteen cases (60% with ARF were seen in third trimester, followed by in postpartum period 9 cases (30%. Most common contributing factors to ARF were Pre-eclampsia, eclampsia and HELLP syndrome 60%, sepsis 56.6%, post abortal ARF 10%. DIC 40%. Haemorrhage as the aetiology for ARF was present 46%, APH in 20% and PPH in 26.6%. The type of ARF was renal in (63% and prerenal (36%; Oliguric seen in 10 patients (33% and high mortality (30%. Among the 20 pregnant patients with ARF, The average period of gestation was 33±2 weeks (30 -36 weeks, 5 cases (25% presented with intrauterine fetal demise and 18 cases (66% had preterm vaginal delivery and 2 cases (10% had induced abortion. And the average birth weight was 2±0.5 kg (1.5 kg. Eight cases (26% required dialysis. 80% of patients recovered completely of renal functions. 63% patients recovered without renal replacement therapy whereas 17% required dialysis. the maternal mortality was 20%, the main reason for mortality was septic shock and multi organ dysfunction (66%. CONCLUSION: ARF related pregnancy was seen commonly in the primigravidae and in the third trimester, the most

  17. Stud arc welding in a magnetic field - Investigation of the influences on the arc motion

    Science.gov (United States)

    Hartz-Behrend, K.; Marqués, J. L.; Forster, G.; Jenicek, A.; Müller, M.; Cramer, H.; Jilg, A.; Soyer, H.; Schein, J.

    2014-11-01

    Stud arc welding is widely used in the construction industry. For welding of studs with a diameter larger than 14 mm a ceramic ferrule is usually necessary in order to protect the weld pool. Disadvantages of using such a ferrule are that more metal is molten than necessary for a high quality welded joint and that the ferrule is a consumable generally thrown away after the welding operation. Investigations show that the ferrule can be omitted when the welding is carried out in a radially symmetric magnetic field within a shielding gas atmosphere. Due to the Lorentz force the arc is laterally shifted so that a very uniform and controlled melting of the stud contact surface as well as of the work piece can be achieved. In this paper a simplified physical model is presented describing how the parameters welding current, flux density of the magnetic field, radius of the arc and mass density of the shielding gas influence the velocity of the arc motion. The resulting equation is subsequently verified by comparing it to optical measurements of the arc motion. The proposed model can be used to optimize the required field distribution for the magnetic field stud welding process.

  18. Stud arc welding in a magnetic field – Investigation of the influences on the arc motion

    International Nuclear Information System (INIS)

    Stud arc welding is widely used in the construction industry. For welding of studs with a diameter larger than 14 mm a ceramic ferrule is usually necessary in order to protect the weld pool. Disadvantages of using such a ferrule are that more metal is molten than necessary for a high quality welded joint and that the ferrule is a consumable generally thrown away after the welding operation. Investigations show that the ferrule can be omitted when the welding is carried out in a radially symmetric magnetic field within a shielding gas atmosphere. Due to the Lorentz force the arc is laterally shifted so that a very uniform and controlled melting of the stud contact surface as well as of the work piece can be achieved. In this paper a simplified physical model is presented describing how the parameters welding current, flux density of the magnetic field, radius of the arc and mass density of the shielding gas influence the velocity of the arc motion. The resulting equation is subsequently verified by comparing it to optical measurements of the arc motion. The proposed model can be used to optimize the required field distribution for the magnetic field stud welding process

  19. Mathematical models of pre-arcing and arcing phenomena in vacuum circuit breakers

    International Nuclear Information System (INIS)

    The main aim of this paper is to show that properties of electrical contact materials are responsible for the metallic vapour pressure at contact closure. Dynamic phenomena accompanying electrical contacts closure in vacuum circuit breakers are considered as consecutive stages, including breakdown, touch, penetration, restitution, bridging and arcing at bouncing. The hybrid mathematical model is elaborated to describe dynamics of the arc and forces acting in contact gap. It includes experimental oscillograms of current, voltage and contact displacement and nonlinear equations for arc, anode and cathode temperature fields and contact motion. Experiments are carried out using a standard vacuum circuit breaker with laser sensors for measurement of contact gap. The special difference path method techniques was applied to take into account oscillations of a fixed contact. The axisymmetrical Stefan problem with two free boundaries corresponding to melting and evaporation interfaces is solved to find dynamics of contact evaporation. It is shown theoretically and confirmed experimentally that in the range of high current the force of metallic vapour pressure at arcing in vacuum is comparable with magnetic repulsion force and should be taken into consideration. Two mechanisms of vapour pressure formation and evolution are discussed, which occur due to explosion of micro-asperities at contact touch or due to arcing after bridge rupture at contact bouncing. (author)

  20. Time between failures model and failure analysis of CNC system

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hai-bo; JIA Ya-zhou; ZHOU Guang-wen

    2007-01-01

    To provide basis for the reliability improvement design of CNC system, the failure data of a type of CNC system in one year are collected under field conditions in workshops. The distribution model parameters of time between failures are estimated by least square method and hypothesis testing is done by d-test method. It is proved that the time between failures of the CNC system follows Weibull distribution and the system has entered into the wear-out failure period. The failure positions and failure causes are analyzed further to indicate the weak subsystems of the CNC system. It can be found that servo unit, electrical system, detecting unit and power supply are principal failure positions and the main failure cause is breakage of components. The corresponding improvement measures are put forward. The paper provides a reference to reliability design and analysis of CNC system for the manufacturer and has great guidance to using and maintaining CNC system for the user.

  1. Copeptin in heart failure

    Directory of Open Access Journals (Sweden)

    Lasota B

    2014-07-01

    Full Text Available Bartosz Lasota,1 Katarzyna Mizia-Stec212nd Department of Cardiology, Medical University of Silesia, Katowice, Poland; 21st Department of Cardiology, Medical University of Silesia, Katowice, PolandAbstract: Copeptin is a novel indicator of arginine–vasopressin activation in the body. Its value has primarily been documented in acute life-threatening conditions mediated by the stress response system. Recently, some studies have revealed copeptin's promising role as a marker in cardiovascular diseases. In our review, we summarize the current knowledge on copeptin in pathophysiology, as well as in risk assessment in different clinical settings involving the cardiovascular system with a special focus on heart failure.Keywords: copeptin, heart failure, arginine–vasopressin

  2. Large seismic faults in the Hellenic arc

    Directory of Open Access Journals (Sweden)

    B. S. Papazachos

    1996-06-01

    Full Text Available Using information concerning reliable fault plane solutions, spatial distribution of strong earthquakes (Ms³ 6.0 as well as sea bottom and coastal topography, properties of the seismic faults (orientation, dimension, type of faulting were determined in seven shallow (h < 40 km seismogenic regions along the convex part of thc Hellenic arc (Hellenic trench and in four seismogenic regions of intermediate depth earthquakes (h = 40-100 km along the concave part of this arc. Except for the northwesternmost part of the Hellenic trench, where the strike-slip Cephalonia transform fault dominates, all other faults along this trench are low angle thrust faults. III thc western part of the trench (Zante-west Crete faults strike NW-SE and dip NE, while in its eastern part (east Crete-Rhodos faults strike WNW-ESE and dip NNE. Such system of faulting can be attributed to an overthrust of the Aegean lithosphere on the eastern Mediterranean lithosphere. The longest of these faults (L = 300 km is that which produced the largest known shallow earthquake in the Mediterranean area (21 July 365, Ms = 8.3 which is located near the southwestern coast of Crete. The second longest such fault (L = l 70 km is that which produced a large earthquake (December 1303, Ms = 8.0 in the easternmost part of the trench (east of Rhodos island. Both earthquakes were associated with gigantic tsunamis which caused extensive damage in the coast of many Eastern Mediterranean countries. Seismic faults of the intermediate depth earthquakes in the shallow part of the Benioff zone (h = 40- 100 km are of strike-slip type, with a thrust component. The orientations of these faults vary along the concave part of the arc in accordance with a subduction of remnants of all old lithospheric slab from the convex side (Mediterranean to the concave side (Aegean of thc Hellenic arc. The longest of these faults (L = 220 km is that which produced the largest known intermediate depth earthquake in the

  3. LHC Magnet test failure

    CERN Multimedia

    2007-01-01

    "On Tueday, March 22, a Fermilab-built quadrupole magnet, one of an "inner triplet" of three focusing magnets, failed a high-pressure test at Point 5 in the tunnel of the LHC accelerator at CERN. Since Tuesday, teams at CERN and Fermilab have worked closely together to address the problem and have identified the cause of the failure. Now they are at work on a solution.:" (1 page)

  4. Renal failure in malaria

    OpenAIRE

    B.S. Das

    2008-01-01

    Acute renal failure (ARF) is seen mostly in Plasmodium falciparum infection, but P. vivax and P. malariae can occasionally contribute for renal impairment. Malarial ARF is commonly found in non-immune adults and older children with falciparum malaria. Occurance of ARF in severe falciparum malaria is quite common in southeast Asia and Indian subcontinent where intensity of malaria transmission is usually low with occasional microfoci of intense transmission. Since precise mechanism of malaria...

  5. Comparative Failure in Science

    OpenAIRE

    Barney G. Glaser, Ph.D., Hon. Ph.D.

    2008-01-01

    A perennial problem for some scientists is their feeling of comparative failure as scientists. This problem becomes clearer if we consider two major sources of this feeling that are inherent in the vary nature of scientific work. (i) In science, strong emphasis is placed on the achievement of recognition; (ii) the typical basic scientist works in a community filled with “great men” who have made important and decisive discoveries in their respective fields; they are the acknowledge guiding li...

  6. Failures in risk management

    OpenAIRE

    Ralph C. Kimball

    2000-01-01

    Risk management has received increasing attention in recent years, both from academics and from practitioners. The heightened interest is the result of a number of coincident secular trends, including increased investment in volatile emerging markets and the growing role of capital markets in both developed and emerging economies, as well as the introduction of volatile financial innovations. Risk management has also attracted attention as a result of the repeated and well-publicized failures...

  7. Mitophagy and heart failure

    OpenAIRE

    Shires, Sarah E.; Gustafsson, Åsa B.

    2015-01-01

    Cardiac mitochondria are responsible for generating energy in the form of ATP through oxidative phosphorylation and are crucial for cardiac function. Mitochondrial dysfunction is a major contributor to loss of myocytes and development of heart failure. Myocytes have quality control mechanisms in place to ensure a network of functional mitochondria. Damaged mitochondria are degraded by a process called mitochondrial autophagy, or mitophagy, where the organelle is engulfed by an autophagosome a...

  8. Failures in implementation

    OpenAIRE

    Karamanof, M.

    1996-01-01

    The purpose of this essay is to propose a comprehensive legal theory of implementation allowing for a deeper understanding of the failures of contemporary Public Administration. Such a theory requires its proper methodology, which is, In fact, the missing link between administrative law and the so-called new sciences. The thesis takes the view that the systemic approach satisfies the above requirements, for it makes possible the broader concepti6n of law, viewed within It...

  9. Characteristics of Atmospheric Pressure Rotating Gliding Arc Plasmas

    Science.gov (United States)

    Zhang, Hao; Zhu, Fengsen; Tu, Xin; Bo, Zheng; Cen, Kefa; Li, Xiaodong

    2016-05-01

    In this work, a novel direct current (DC) atmospheric pressure rotating gliding arc (RGA) plasma reactor has been developed for plasma-assisted chemical reactions. The influence of the gas composition and the gas flow rate on the arc dynamic behaviour and the formation of reactive species in the N2 and air gliding arc plasmas has been investigated by means of electrical signals, high speed photography, and optical emission spectroscopic diagnostics. Compared to conventional gliding arc reactors with knife-shaped electrodes which generally require a high flow rate (e.g., 10–20 L/min) to maintain a long arc length and reasonable plasma discharge zone, in this RGA system, a lower gas flow rate (e.g., 2 L/min) can also generate a larger effective plasma reaction zone with a longer arc length for chemical reactions. Two different motion patterns can be clearly observed in the N2 and air RGA plasmas. The time-resolved arc voltage signals show that three different arc dynamic modes, the arc restrike mode, takeover mode, and combined modes, can be clearly identified in the RGA plasmas. The occurrence of different motion and arc dynamic modes is strongly dependent on the composition of the working gas and gas flow rate. supported by National Natural Science Foundation of China (No. 51576174), the Specialized Research Fund for the Doctoral Program of Higher Education of China (No. 20120101110099) and the Fundamental Research Funds for the Central Universities (No. 2015FZA4011)

  10. Characteristics of Atmospheric Pressure Rotating Gliding Arc Plasmas

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hao; ZHU Fengsen; TU Xin; BO Zheng; CEN Kefa; LI Xiaodong

    2016-01-01

    In this work,a novel direct current (DC) atmospheric pressure rotating gliding arc (RGA) plasma reactor has been developed for plasma-assisted chemical reactions.The influence of the gas composition and the gas flow rate on the arc dynamic behaviour and the formation of reactive species in the N2 and air gliding arc plasmas has been investigated by means of electrical signals,high speed photography,and optical emission spectroscopic diagnostics.Compared to conventional gliding arc reactors with knife-shaped electrodes which generally require a high flow rate (e.g.,10-20 L/min) to maintain a long arc length and reasonable plasma discharge zone,in this RGA system,a lower gas flow rate (e.g.,2 L/min) can also generate a larger effective plasma reaction zone with a longer arc length for chemical reactions.Two different motion patterns can be clearly observed in the N2 and air RGA plasmas.The time-resolved arc voltage signals show that three different arc dynamic modes,the arc restrike mode,takeover mode,and combined modes,can be clearly identified in the RGA plasmas.The occurrence of different motion and arc dynamic modes is strongly dependent on the composition of the working gas and gas flow rate.

  11. Series Arc Fault Detection Algorithm Based on Autoregressive Bispectrum Analysis

    Directory of Open Access Journals (Sweden)

    Kai Yang

    2015-10-01

    Full Text Available Arc fault is one of the most critical reasons for electrical fires. Due to the diversity, randomness and concealment of arc faults in low-voltage circuits, it is difficult for general methods to protect all loads from series arc faults. From the analysis of many series arc faults, a large number of high frequency signals generated in circuits are found. These signals are easily affected by Gaussian noise which is difficult to be eliminated as a result of frequency aliasing. Thus, a novel detection algorithm is developed to accurately detect series arc faults in this paper. Initially, an autoregressive model of the mixed high frequency signals is modelled. Then, autoregressive bispectrum analysis is introduced to analyze common series arc fault features. The phase information of arc fault signal is preserved using this method. The influence of Gaussian noise is restrained effectively. Afterwards, several features including characteristic frequency, fluctuation of phase angles, diffused distribution and incremental numbers of bispectrum peaks are extracted for recognizing arc faults. Finally, least squares support vector machine is used to accurately identify series arc faults from the load states based on these frequency features of bispectrum. The validity of the algorithm is experimentally verified obtaining arc fault detection rate above 97%.

  12. Lithium Isotopic Composition of Aleutian Arc Magmas

    Science.gov (United States)

    Rudnick, R. L.; Park, Y.; Liu, X.; Kay, S. M.; Kay, R. W.

    2012-12-01

    The lithium isotopic compositions of inputs to subduction zones can be highly variable. For example, altered oceanic crust is isotopically heavy (δ7Li = 4 to 22, Chan et al., 1996; Bouman et al., 2004) due to uptake of seawater Li (32). Sea floor sediments can have highly variable compositions, ranging from isotopically heavy pelagic sediments (6 to 14) to isotopically light terrigneous clays (-1.5 to 5), derived from highly weathered continental crust (Chan et al., 2006). Despite this variability in inputs, arc outputs (magmatic rocks) typically have mantle-like δ7Li (e.g., 2 to 6; Tomascak et al., 2002; Walker et al., 2009). To explore the behavior of lithium and its isotopes in arcs, we have analyzed [Li] and δ7Li in 48 lavas and plutons from the Aleutian island arc, which span the temporal (0 to 38 Ma), geographical (165-184oW) and compositional variations (SiO2 = 46-70 wt.%) seen in this arc. Previous studies have indicated a systematic geographic change in lava chemistry related to changing sediment composition along the arc (terrigneous in the east, pelagic in the west, e.g., Kay and Kay, 1994; Yogodinski et al., 2010), as well as temporal changes that may also reflect changes in sedimentary input (Kay and Kay, 1994), and we wished to determine if Li isotopes also reflect such changes. Lithium concentration [Li] shows a generally positive correlation with SiO2, consistent with the expected incompatible behavior of Li during magmatic differentiation. Intrusive rocks (all from the Adak region) show more scatter than lavas on this plot, suggesting the influence of cumulate processes. The δ7Li of the rocks span an immense range from -1 to +29, well outside the values considered typical for the MORB-source mantle (e.g., 2-6). However, the majority of the samples (28 out of 48) have δ7Li falling within the range of typical mantle values. There is a general tendency for the lavas (all but one are adakite (~11 Ma, Kay, 1978) has a δ7Li of 3.7. There is no

  13. Arc generation from sputtering plasma-dielectric inclusion interactions

    International Nuclear Information System (INIS)

    Arcing during sputter deposition and etching is a significant cause of particle defect generation during device fabrication. In this article we report on the effect of aluminum oxide inclusion size, shape, and orientation on the propensity for arcing during sputtering of aluminum targets. The size, shape, and orientation of a dielectric inclusion plays a major role in determining the propensity for arcing and macroparticle emission. In previous studies we found that there is a critical inclusion size required for arcing to occur. In this article we used high-speed videos, electric arc detection, and measurements of particle defect density on wafers to study the effect of Al2O3 inclusion size, shape, and orientation on arc rate, intensity, and silicon wafer particle defect density. We found that the cross-sectional area of the inclusion exposed to the sputtering plasma is the critical parameter that determines the arc rate and rate of macroparticle emission. Analysis of the arc rate, particle defect density, and the intensity of the optical emission from the arcing plasma indicates that the critical aluminum oxide inclusion area for arcing is 0.22±0.1 mm2 when the sputtering plasma sheath dark-space λd, is 0.51 mm. Inclusions with areas greater than this critical value readily induce arcing and macroparticle ejection during sputtering. Inclusions below this critical size do not cause arcing or macroparticle ejection. When the inclusion major axis is longer than 2λd and lies perpendicular to the sputter erosion track tangent, the arcing activity increases significantly over the case where the inclusion major axis lies parallel to the erosion track tangent

  14. Single Arc Volumetric Modulated Arc Therapy of head and neck cancer

    DEFF Research Database (Denmark)

    Bertelsen, Anders; Hansen, Christian Rønn; Johansen, Jørgen;

    2010-01-01

    named SmartArc and its capability to generate treatment plans for head and neck cancer was tested. METHODS: Twenty-five patients with oropharyngeal or hypopharyngeal carcinoma, previously treated with IMRT by means of Pinnacle and Elekta accelerators, were replanned with single arc VMAT. The VMAT......BACKGROUND: The quality of Volumetric Modulated Arc Therapy (VMAT) plans is highly dependent on the performance of the optimization algorithm used. Recently new algorithms have become available which are capable of generating VMAT plans for Elekta accelerators. The VMAT algorithm in Pinnacle is...... planning objectives were to achieve clinical target coverage and sparing of the organs at risk (OAR). Comparison with the original clinically used IMRT was made by evaluating (1) dose-volume histograms (DVHs) for PTVs, (2) DVHs for OARs, (3) delivery time and monitor units (MU), and (4) treatment accuracy...

  15. Heart Failure Society of America

    Science.gov (United States)

    ... Site Terms and Conditions Copyright © 2016 Heart Failure Society of America. All Rights Reserved 2016 Board Review ... Membership Membership Information Membership in the Heart Failure Society is open to all health care professionals with ...

  16. Your Heart Failure Healthcare Team

    Science.gov (United States)

    ... Tools & Resources Stroke More Your Heart Failure Healthcare Team Updated:Mar 25,2016 Patients with heart failure ... good relationships with all the members of this team. Learn to talk to them openly and honestly ...

  17. Failure Analysis for Improved Reliability

    Science.gov (United States)

    Sood, Bhanu

    2016-01-01

    Outline: Section 1 - What is reliability and root cause? Section 2 - Overview of failure mechanisms. Section 3 - Failure analysis techniques (1. Non destructive analysis techniques, 2. Destructive Analysis, 3. Materials Characterization). Section 4 - Summary and Closure

  18. Influence of the vacuum-arc source configuration and arc discharge parameters on the evolution and location of arc spots on the cathode surface

    Directory of Open Access Journals (Sweden)

    J. Walkowicz

    2009-12-01

    Full Text Available Purpose: The paper presents investigations of the evolution, structure and location of arc spots on the cathode frontal surfaces of two types of industrial arc sources.Design/methodology/approach: The temporal behaviour of cathode spots was recorded with the use of a fast CCD camera. The experiments were performed at four values of arc current, nine compositions of the process atmosphere N2+C2H2 and three pressure ranges of the process atmosphere.Findings: The analysis of the recorded pictures revealed the fine structure of the arc discharge for the investigated range of process conditions. Both temporal and spatial behaviour of cathode spots were different for both investigated arc sources. The correspondence between radial distributions of the cathode spots on the cathode surface and radial distribution of plasma flow elements analysed in the volume of the vacuum chamber was revealed.Research limitations/implications: The paper show experimental methodology that can be used for the research of the specificity of cathode spots movement on the cathodes made from different materials.Originality/value: The originality of the research presented in the paper consists in assigning overall correlation between vacuum-arc source configuration and parameters of vacuum-arc discharge – on the one hand, and space-time behaviour of the arc spots during their movement on the circular cathode surface and radial distribution of excited and ionized atoms of the cathode material in the deposition chamber – on the other.

  19. Electrophysiological Remodeling in Heart Failure

    OpenAIRE

    Wang, Yanggan; Hill, Joseph A.

    2010-01-01

    Heart failure affects nearly 6 million Americans, with a half-million new cases emerging each year. Whereas up to 50% of heart failure patients die of arrhythmia, the diverse mechanisms underlying heart failure-associated arrhythmia are poorly understood. As a consequence, effectiveness of antiarrhythmic pharmacotherapy remains elusive. Here, we review recent advances in our understanding of heart failure-associated molecular events impacting the electrical function of the myocardium. We appr...

  20. The origins of acicular ferrite in gas metal arc and submerged arc welds

    OpenAIRE

    Brothers, Daniel G.

    1994-01-01

    The nature of weld metal inclusions in relation to the formation of acicular ferrite was investigated. Gas-metal arc welds (GMAW) on High Strength Low Alloy (HSLA) plate with varying amounts of oxygen and/or carbon dioxide added to the argon cover gas and submerged arc welds (SAW) on HY-100 plate with five different fluxes were analyzed. This analysis determined the effect of weld metal composition on non-metallic inclusion composition and the ultimate effects on the formation of acicular fer...

  1. Application of Python in ArcGIS%Python在ArcGIS中的应用

    Institute of Scientific and Technical Information of China (English)

    朱道强; 关海涛

    2013-01-01

    通过简要介绍利用Python语言编写脚本在ArcGIS中进行数据批处理的基础方法,提出了一种减轻现今数据生产中作业人员进行数据处理强度的方法.%Through a brief introduction on the use of Python language data batch processing based method for script in ArcGIS,thus put forward the method to reduce the data in the production operation personnel data processing strength.

  2. Fluid Flow Modeling of Arc Plasma and Bath Circulation in DC Electric Arc Furnace

    Institute of Scientific and Technical Information of China (English)

    WANG Feng-hua; JIN Zhi-jian; ZHU Zi-shu

    2006-01-01

    A mathematical model describing the flow field, heat transfer and the electromagnetic phenomenon in a DC electric arc furnace has been developed. First the governing equations in the arc plasma region are solved and the calculated results of heat transfer, current density and shear stresses on the anode surface are used as boundary conditions in a model of molten bath. Then a two-dimensional time-dependent model is used to describe the flow field and electromagnetic phenomenon in the molten bath. Moreover, the effect of bottom electrode diameter on the circulation of molten bath is studied.

  3. Reabsorption of Radiation in Water-Vortex Stabilized Electric arc and Influence on arc Performance

    Czech Academy of Sciences Publication Activity Database

    Jeništa, Jiří

    Vol. 2. Brno: Department of Power Electrical and Electronic Engineering, Brno University of Technology, 2003 - (Gross, B.; Vávra, Z.; Bartl, J.), s. 312-315. (2). ISBN 80-214-2307-2. [Symposium on Physics of Switching arc/15th./. Nové Město na Moravě (CZ), 22.09.2003-26.09.2003] R&D Projects: GA ČR GA202/02/1027 Institutional research plan: CEZ:AV0Z2043910 Keywords : electric arc, reabsorption, radiation model Subject RIV: BL - Plasma and Gas Discharge Physics

  4. Stochastic failure modelling of unidirectional composite ply failure

    International Nuclear Information System (INIS)

    Stochastic failure envelopes are generated through parallelised Monte Carlo Simulation of a physically based failure criteria for unidirectional carbon fibre/epoxy matrix composite plies. Two examples are presented to demonstrate the consequence on failure prediction of both statistical interaction of failure modes and uncertainty in global misalignment. Global variance-based Sobol sensitivity indices are computed to decompose the observed variance within the stochastic failure envelopes into contributions from physical input parameters. The paper highlights a selection of the potential advantages stochastic methodologies offer over the traditional deterministic approach.

  5. CRITERIA FOR ROCK ENGINEERING FAILURE

    Institute of Scientific and Technical Information of China (English)

    ZHUDeren; ZHANGYuzhuo

    1995-01-01

    A great number of underground rock projects are maintained in the rock mass which is subject to rock damage and failure development. In many cases, the rock. engineering is still under normal working conditions even though rock is already fails to some extent. This paper introduces two different concepts: rock failure and rock engineering failure. Rock failure is defined as a mechanical state under which an applicable characteristic is changed or lost.However, the rock engineering failure is an engineering state under which an applicable function is changed or lost. The failure of surrounding rocks is the major reason of rock engineering failure. The criterion of rock engineering failure depends on the limit of applicable functions. The rock engineering failure state possesses a corresponding point in rock failure state. In this paper, a description of rock engineering failure criterion is given by simply using a mechanical equation or expression. It is expected that the study of rock engineering failure criterion will be an optimal approach that combines research of rock mechanics with rock engineering problems.

  6. Helium release rates and ODH calculations from RHIC magnet cooling line failure

    International Nuclear Information System (INIS)

    A catastrophic failure of the magnet cooling lines, similar to the LHC superconducting bus failure incident, could discharge cold helium into the RHIC tunnel and cause an Oxygen Deficiency Hazard (ODH) problem. A SINDA/FLUINT(regsign) model, which simulated the 4.5K/4 atm helium flowing through the magnet cooling system distribution lines, then through a line break into the insulating vacuum volumes and discharging via the reliefs into the RHIC tunnel, had been developed. Arc flash energy deposition and heat load from the ambient temperature cryostat surfaces are included in the simulations. Three typical areas: the sextant arc, the Triplet/DX/D0 magnets, and the injection area, had been analyzed. Results, including helium discharge rates, helium inventory loss, and the resulting oxygen concentration in the RHIC tunnel area, are reported. Good agreement had been achieved when comparing the simulation results, a RHIC sector depressurization test measurement, and some simple analytical calculations.

  7. Helium release rates and ODH calculations from RHIC magnet cooling line failure

    Energy Technology Data Exchange (ETDEWEB)

    Liaw, C.J.; Than, Y.; Tuozzolo, J.

    2011-03-28

    A catastrophic failure of the magnet cooling lines, similar to the LHC superconducting bus failure incident, could discharge cold helium into the RHIC tunnel and cause an Oxygen Deficiency Hazard (ODH) problem. A SINDA/FLUINT{reg_sign} model, which simulated the 4.5K/4 atm helium flowing through the magnet cooling system distribution lines, then through a line break into the insulating vacuum volumes and discharging via the reliefs into the RHIC tunnel, had been developed. Arc flash energy deposition and heat load from the ambient temperature cryostat surfaces are included in the simulations. Three typical areas: the sextant arc, the Triplet/DX/D0 magnets, and the injection area, had been analyzed. Results, including helium discharge rates, helium inventory loss, and the resulting oxygen concentration in the RHIC tunnel area, are reported. Good agreement had been achieved when comparing the simulation results, a RHIC sector depressurization test measurement, and some simple analytical calculations.

  8. Optical arc sensor using energy harvesting power source

    Science.gov (United States)

    Choi, Kyoo Nam; Rho, Hee Hyuk

    2016-06-01

    Wireless sensors without external power supply gained considerable attention due to convenience both in installation and operation. Optical arc detecting sensor equipping with self sustaining power supply using energy harvesting method was investigated. Continuous energy harvesting method was attempted using thermoelectric generator to supply standby power in micro ampere scale and operating power in mA scale. Peltier module with heat-sink was used for high efficiency electricity generator. Optical arc detecting sensor with hybrid filter showed insensitivity to fluorescent and incandescent lamps under simulated distribution panel condition. Signal processing using integrating function showed selective arc discharge detection capability to different arc energy levels, with a resolution below 17J energy difference, unaffected by bursting arc waveform. The sensor showed possibility for application to arc discharge detecting sensor in power distribution panel. Also experiment with proposed continuous energy harvesting method using thermoelectric power showed possibility as a self sustainable power source of remote sensor.

  9. Dispersive effects of transverse displacements of SLC Arc magnets

    International Nuclear Information System (INIS)

    The SLC Arc magnets are subject to random displacements and field errors resulting in unpredictable transverse displacement of the central trajectory from that of the design. The chosen method of correcting this perturbed trajectory in the SLC Arcs utilizes mechanical movement of the combined function magnets which compose the Arc transport lines. Here we present the results of a recent investigation substantiating the earlier results which led to the adoption of this method

  10. The Detection and Statistics of Giant Arcs behind CLASH Clusters

    Science.gov (United States)

    Xu, Bingxiao; Postman, Marc; Meneghetti, Massimo; Seitz, Stella; Zitrin, Adi; Merten, Julian; Maoz, Dani; Frye, Brenda; Umetsu, Keiichi; Zheng, Wei; Bradley, Larry; Vega, Jesus; Koekemoer, Anton

    2016-02-01

    We developed an algorithm to find and characterize gravitationally lensed galaxies (arcs) to perform a comparison of the observed and simulated arc abundance. Observations are from the Cluster Lensing And Supernova survey with Hubble (CLASH). Simulated CLASH images are created using the MOKA package and also clusters selected from the high-resolution, hydrodynamical simulations, MUSIC, over the same mass and redshift range as the CLASH sample. The algorithm's arc elongation accuracy, completeness, and false positive rate are determined and used to compute an estimate of the true arc abundance. We derive a lensing efficiency of 4 ± 1 arcs (with length ≥6″ and length-to-width ratio ≥7) per cluster for the X-ray-selected CLASH sample, 4 ± 1 arcs per cluster for the MOKA-simulated sample, and 3 ± 1 arcs per cluster for the MUSIC-simulated sample. The observed and simulated arc statistics are in full agreement. We measure the photometric redshifts of all detected arcs and find a median redshift zs = 1.9 with 33% of the detected arcs having zs > 3. We find that the arc abundance does not depend strongly on the source redshift distribution but is sensitive to the mass distribution of the dark matter halos (e.g., the c-M relation). Our results show that consistency between the observed and simulated distributions of lensed arc sizes and axial ratios can be achieved by using cluster-lensing simulations that are carefully matched to the selection criteria used in the observations.

  11. Analisis dan Reduksi Bahaya ARC Flash pada Sistem Kelistrikan

    OpenAIRE

    Firman Aji Prasongko; Ontoseno Penangsang; Margo Pujiantara

    2012-01-01

    Upaya terakhir untuk menghitung bahaya yang berhubungan dengan potensi bahaya arc flash bergantung pada proteksi arus lebih untuk menghilangkan kondisi saat diberi gangguan. Efektivitas berbagai perangkat ditentukan oleh clearing time terkait dengan gangguan arus maksimum yang ada untuk setiap lokasi sistem. Industri komersial mulai melakukan prosedur pelabelan arc flash dan mulai mengenali pencegahan arc flash sebagai bagian dari program safety, perhitungan current method memungkinkan untuk ...

  12. Fluctuation Phenomenon Analysis of an Arc Plasma Spraying Jet

    Institute of Scientific and Technical Information of China (English)

    赵文华; 田阔; 刘笛; 张冠忠

    2001-01-01

    The effects of three factors, including the power supply, the arc behaviour in the arc channel and the fluid dynamic process of the jet, on a plasma spraying jet have been experimentally detected by means of spectroscopic diagnostic techniques. The fast Fourier transform method has been applied to the analysis of the arc voltage and spectral line intensity of the jet. The three factors have been studied and distinguished from each other.

  13. Measured resolutions of the Arc and Linac BPM systems

    International Nuclear Information System (INIS)

    The 6'' long final focus beam position monitors (short FF BPM's are longer, thus deliver more signal after a 15 nanosecond filter, than either the Linac or Arc monitors. The purpose of this note is to compare the resolution of the Arc vs Linac electronics when applied to a short FF 2'' diameter BPM. A method of calibrating the Arc modules is also tested and briefly discussed. The range of each DAC setting to minimize digitization error is also calculated

  14. A solution for potential flow over an arc fiber

    OpenAIRE

    Wang Wenxi; He Qing; Chen Nian; Zhou Yuan; Xie Mingliang

    2012-01-01

    In the paper, the flow field around an arc fiber is studied. Based on the Zhukovsky conversion, the potential and stream functions are derived. The results show that the flow fields depend on geometric properties of the arc fiber and the orientation angle of the incoming flow. The flow field developed in this paper can be used to predict the single-fiber efficiency for the arc fiber.

  15. A solution for potential flow over an arc fiber

    Directory of Open Access Journals (Sweden)

    Wang Wenxi

    2012-01-01

    Full Text Available In the paper, the flow field around an arc fiber is studied. Based on the Zhukovsky conversion, the potential and stream functions are derived. The results show that the flow fields depend on geometric properties of the arc fiber and the orientation angle of the incoming flow. The flow field developed in this paper can be used to predict the single-fiber efficiency for the arc fiber.

  16. THE EFFECT OF THE ARCS MOTIVATION MODEL UPON

    OpenAIRE

    DEDE, Yüksel

    2003-01-01

    In this research, the effect of the ARCS Motivation Model upon the students’ motivation towards mathematics was investigated. Therefore, ARCS Motivation Model was applied to 7th grade students at a middle school in Ankara at 2001-2002 terms. In research, experimental group studied ARCS Motivation Model, on the other hand the control group received traditionally designed mathematics instruction over 4 weeks. Motivation test was developed and used as a pre and post test. Independent-samp...

  17. Programming ArcGIS 10.1 with Python cookbook

    CERN Document Server

    Pimpler, Eric

    2013-01-01

    This book is written in a helpful, practical style with numerous hands-on recipes and chapters to help you save time and effort by using Python to power ArcGIS to create shortcuts, scripts, tools, and customizations.""Programming ArcGIS 10.1 with Python Cookbook"" is written for GIS professionals who wish to revolutionize their ArcGIS workflow with Python. Basic Python or programming knowledge is essential(?).

  18. Overview of arc design options: Deliverable D2.1

    CERN Document Server

    Chance, Antoine

    2016-01-01

    This document describes the collider layouts to be taken into account for further detailed studies. The optimization of the arc cell lattice and the choice made on the dispersion suppressor are explained. The arc lattice is detailed with the procedures to tune the collider ring and to correct the chromaticity. The correction schemes of the orbit, of the dynamic aperture and of the spurious dispersion are detailed. Finally, the properties of the arc design at the injection energy are shown.

  19. Unusual Cathode Erosion Patterns Observed for Steered Arc Sources

    OpenAIRE

    Kolbeck, Jonathan; Anders, André

    2014-01-01

    A cathodic arc source with a magnetron-type magnetic field was investigated for stability, erosion, and compatibility with a linear macroparticle filter. Here we report about unusual arc spot erosion patterns, which were narrow (~ 2 mm) with periodic pits when operating in argon, and broad (~ 10 mm) with periodic groves and ridges when operating in an argon and oxygen mixtures. These observations can be correlated with the ignition probability for type 2 and type 1 arc spots, respectively.

  20. Experimental investigation of energy balance in plasma arc cutting process

    Czech Academy of Sciences Publication Activity Database

    Kavka, Tetyana; Tossens, S.; Mašláni, Alan; Konrád, Miloš; Pauser, H.; Stehrer, T.

    Vol. 511. Bristol: IOP Publishing, 2014, 012067-012067. (IoP. 511). ISSN 1742-6588. [International Congress on Plasma Physics (ICPP) / 13th Latin American Workshop on Plasma Physics (LAWPP)/15./. Santiago, CHILE (CL), 08.08.2010-13.08.2010] Institutional support: RVO:61389021 Keywords : plasma arc cutting * arc cutting * plasma arc Subject RIV: BL - Plasma and Gas Discharge Physics http://iopscience.iop.org/1742-6596/511/1/012067/pdf/1742-6596_511_1_012067.pdf

  1. Plasma and solar array arcing caused by space debris impact

    OpenAIRE

    Fukushige, Shinya; Akahoshi, Yasuhiro; Watanabe, Keiko; Nagasaki, Toshikazu; Sugawara, Kensho; Kora, Takao; 福重 進也; 赤星 保浩; 渡辺 圭子; 長崎 俊和; 菅原 賢尚; 高良 隆男; Cho, Mengu

    2008-01-01

    There is high possibility that space debris impacts to a solar array paddle in spacecraft parts, because the solar array paddle has large area. Space debris impact to the solar array causes not only mechanical damage but also electrical damage such as arcing on the solar array through local high density plasma created by hypervelocity impact. In the worst case, Joule heating of this arcing carbonizes insulation layer and permanent short-circuit path is created. This is permanent sustained arc...

  2. Steam generator tube failures

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, P.E.; Shah, V.N.; Ward, L.W.; Ellison, P.G.

    1996-04-01

    A review and summary of the available information on steam generator tubing failures and the impact of these failures on plant safety is presented. The following topics are covered: pressurized water reactor (PWR), Canadian deuterium uranium (CANDU) reactor, and Russian water moderated, water cooled energy reactor (VVER) steam generator degradation, PWR steam generator tube ruptures, the thermal-hydraulic response of a PWR plant with a faulted steam generator, the risk significance of steam generator tube rupture accidents, tubing inspection requirements and fitness-for-service criteria in various countries, and defect detection reliability and sizing accuracy. A significant number of steam generator tubes are defective and are removed from service or repaired each year. This wide spread damage has been caused by many diverse degradation mechanisms, some of which are difficult to detect and predict. In addition, spontaneous tube ruptures have occurred at the rate of about one every 2 years over the last 20 years, and incipient tube ruptures (tube failures usually identified with leak detection monitors just before rupture) have been occurring at the rate of about one per year. These ruptures have caused complex plant transients which have not always been easy for the reactor operators to control. Our analysis shows that if more than 15 tubes rupture during a main steam line break, the system response could lead to core melting. Although spontaneous and induced steam generator tube ruptures are small contributors to the total core damage frequency calculated in probabilistic risk assessments, they are risk significant because the radionuclides are likely to bypass the reactor containment building. The frequency of steam generator tube ruptures can be significantly reduced through appropriate and timely inspections and repairs or removal from service.

  3. Steam generator tube failures

    International Nuclear Information System (INIS)

    A review and summary of the available information on steam generator tubing failures and the impact of these failures on plant safety is presented. The following topics are covered: pressurized water reactor (PWR), Canadian deuterium uranium (CANDU) reactor, and Russian water moderated, water cooled energy reactor (VVER) steam generator degradation, PWR steam generator tube ruptures, the thermal-hydraulic response of a PWR plant with a faulted steam generator, the risk significance of steam generator tube rupture accidents, tubing inspection requirements and fitness-for-service criteria in various countries, and defect detection reliability and sizing accuracy. A significant number of steam generator tubes are defective and are removed from service or repaired each year. This wide spread damage has been caused by many diverse degradation mechanisms, some of which are difficult to detect and predict. In addition, spontaneous tube ruptures have occurred at the rate of about one every 2 years over the last 20 years, and incipient tube ruptures (tube failures usually identified with leak detection monitors just before rupture) have been occurring at the rate of about one per year. These ruptures have caused complex plant transients which have not always been easy for the reactor operators to control. Our analysis shows that if more than 15 tubes rupture during a main steam line break, the system response could lead to core melting. Although spontaneous and induced steam generator tube ruptures are small contributors to the total core damage frequency calculated in probabilistic risk assessments, they are risk significant because the radionuclides are likely to bypass the reactor containment building. The frequency of steam generator tube ruptures can be significantly reduced through appropriate and timely inspections and repairs or removal from service

  4. Active Subduction Beneath The Gibraltar Arc

    Science.gov (United States)

    Gutscher, M.-A.; Malod, J.; Rehault, J.-P.; Contrucci, I.; Klingelhoefer, F.; Spakman, W.; Sismar Scientific Team

    The Gibraltar region features the arcuate Betic - Rif mountain belt with outward di- rected thrusting, surrounding a zone of strong Neogene subsidence and crustal thin- ning in the Western Alboran Sea. Until now its geodynamic interpretation has re- mained controversial. The Gibraltar Arc is located at the eastern end of the Azores- Gibraltar transform, a diffuse transpressional plate boundary between the Iberian and African Plates. Attention has recently been focussed on this plate boundary, while seeking the likely source of the destructive Lisbon great earthquake (M 8.5 - 9) and tsunami of 1755. The SISMAR marine seismic survey conducted in April 2001 ac- quired over 3000 km of 360-channel seismic data with a 4.5 km long streamer and 1000 km of wide-angle data recorded by ocean bottom seismometers (OBS), com- pletely spanning the actively deforming region between the margins of Portugal and northwest Morocco. Results from this seismic survey reveal a thick chaotic sedimen- tary mass west of Gibraltar to be an actively deforming accretionary wedge, with east dipping thrust faults disrupting the seafloor and soleing out to an east dipping decolle- ment. New travel-time tomographic results image a continuous east dipping body with high seismic velocities (i.e. a cold slab of oceanic lithosphere) descending from the Atlantic domain of the Gulf of Cadiz, passing through intermediate depth (60 - 120 km) seismicity beneath the Gibraltar Arc and Western Alboran Sea, and merging with a region of deep focus earthquakes 600 - 660 km below Granada Spain. Together these provide compelling evidence for an active east dipping subduction zone. Slab rollback towards the west provides a plausible mechanism for extension and subsidence in the Alboran Sea, while the associated westward advance of the Gibraltar Arc drives com- pressional deformation in the accretionary wedge where active mud volcanoes have recently been discovered.

  5. Animation of boom failure processes

    International Nuclear Information System (INIS)

    Computer animations of oil boom failure mechanisms were discussed. The animations are useful in demonstrating the transient processes of boom failure. They consist of a series of images obtained from the graphical output of a computational fluid dynamics program, FLUENT, while the modeling is based on boom failure experiments carried out in flowing water channels. The animations can be viewed on a PC running under Windows '95. Three types of failures are presented, i. e. drainage failure, droplet entrainment and critical accumulation. 11 refs., 3 figs

  6. Premature ovarian failure

    Directory of Open Access Journals (Sweden)

    Persani Luca

    2006-04-01

    Full Text Available Abstract Premature ovarian failure (POF is a primary ovarian defect characterized by absent menarche (primary amenorrhea or premature depletion of ovarian follicles before the age of 40 years (secondary amenorrhea. It is a heterogeneous disorder affecting approximately 1% of women e.g. Turner syndrome represent the major cause of primary amenorrhea associated with ovarian dysgenesis. Despite the description of several candidate genes, the cause of POF remains undetermined in the vast majority of the cases. Management includes substitution of the hormone defect by estrogen/progestin preparations. The only solution presently available for the fertility defect in women with absent follicular reserve is ovum donation.

  7. Renal Failure in Pregnancy.

    Science.gov (United States)

    Balofsky, Ari; Fedarau, Maksim

    2016-01-01

    Renal failure during pregnancy affects both mother and fetus, and may be related to preexisting disease or develop secondary to diseases of pregnancy. Causes include hypovolemia, sepsis, shock, preeclampsia, thrombotic microangiopathies, and renal obstruction. Treatment focuses on supportive measures, while pharmacologic treatment is viewed as second-line therapy, and is more useful in mitigating harmful effects than treating the underlying cause. When supportive measures and pharmacotherapy prove inadequate, dialysis may be required, with the goal being to prolong pregnancy until delivery is feasible. Outcomes and recommendations depend primarily on the underlying cause. PMID:26600445

  8. Acute liver failure

    DEFF Research Database (Denmark)

    Bernal, William; Lee, William M; Wendon, Julia;

    2015-01-01

    Over the last three decades acute liver failure (ALF) has been transformed from a rare and poorly understood condition with a near universally fatal outcome, to one with a well characterized phenotype and disease course. Complex critical care protocols are now applied and emergency liver...... transplantation (ELT) is an established treatment option. These improvements in care are such that the majority of patients may now be expected to survive (Fig. 1). Key features of the condition have changed dramatically over time, with a remarkable fall in the incidence of cerebral edema and intracranial...

  9. Pulmonary siderosis (pneumoconiosis) in an arc welder

    Energy Technology Data Exchange (ETDEWEB)

    Triebel, H.J.; Spielmann, R.P.; Jessel, A.

    1988-02-01

    An arc welder of 32 years of age is presented with a random finding of miliar reticulonodular shadows in the plain film of the thorax. Subjectively and objectively the patient appears healthy. The presence of a pneumoconiosis is confirmed by biopsy. Differential diagnosis had to consider sarcoidosis and pulmonary siderosis in view of the known professional anamnesis. This case report underlines the repeated demand to assess X-ray films of the thoracic organs only if the clinical findings and anamnesis are thoroughly known.

  10. A new approach to turbulent arcs problem

    International Nuclear Information System (INIS)

    A new hypothesis is advanced which assumes the mass being a charge that has not only the known static interaction but also the dynamic one. Moving mass charge produces a special field likewise the electric charge creates magnetic one. Dynamic Interaction of moving mass with the copartner field bends the particles trajectory and creates vortexes which are responsible for flow turbulization. The permeability constant and basic relations are derived for the ''vortex'' field. Some verifications of the hypothesis is done for ''cold'' flow and arc discharge. (author)

  11. The ATLAS ARC backend to HPC

    Science.gov (United States)

    Haug, S.; Hostettler, M.; Sciacca, F. G.; Weber, M.

    2015-12-01

    The current distributed computing resources used for simulating and processing collision data collected by ATLAS and the other LHC experiments are largely based on dedicated x86 Linux clusters. Access to resources, job control and software provisioning mechanisms are quite different from the common concept of self-contained HPC applications run by particular users on specific HPC systems. We report on the development and the usage in ATLAS of a SSH backend to the Advanced Resource Connector (ARC) middleware to enable HPC compliant access and on the corresponding software provisioning mechanisms.

  12. Pulmonary siderosis (pneumoconiosis) in an arc welder

    International Nuclear Information System (INIS)

    An arc welder of 32 years of age is presented with a random finding of miliar reticulonodular shadows in the plain film of the thorax. Subjectively and objectively the patient appears healthy. The presence of a pneumoconiosis is confirmed by biopsy. Differential diagnosis had to consider sarcoidosis and pulmonary siderosis in view of the known professional anamnesis. This case report underlines the repeated demand to assess X-ray films of the thoracic organs only if the clinical findings and anamnesis are thoroughly known. (orig.)

  13. The ATLAS ARC backend to HPC

    CERN Document Server

    Haug, Sigve; The ATLAS collaboration; Sciacca, Francesco Giovanni; Weber, Michele

    2015-01-01

    The current distributed computing resources used for simulating and processing collision data collected by the LHC experiments are largely based on dedicated x86 Linux clusters. Access to resources, job control and software provisioning mechanisms are quite different from the common concept of self-contained HPC applications run by particular users on specific HPC systems. We report on the development and the usage of a ssh back-end to the Advanced Resource Connector (ARC) middleware to enable HPC compliant access and on the corresponding software provisioning mechanisms.

  14. The ATLAS ARC backend to HPC

    CERN Document Server

    Haug, Sigve; The ATLAS collaboration; Sciacca, Francesco Giovanni; Weber, Michele

    2015-01-01

    The current distributed computing resources used for simulating and processing collision data collected by the LHC experiments are largely based on dedicated x86 Linux clusters. Access to resources, job control and software provisioning mechanisms are quite different from the common concept of self-contained HPC applications run by particular users on specific HPC systems. We report on the development and the usage of a SSH back-end to the Advanced Resource Connector (ARC) middleware to enable HPC compliant access and on the corresponding software provisioning mechanisms.

  15. Dynamic behaviour of an electric arc gas discharge

    International Nuclear Information System (INIS)

    The time-dependent energy and circuit equations are solved numerically to obtain temperature profiles, current-voltage characteristics and electric field strength vs axial temperature diagrams in the asymptotic region of a wall-stabilized electric arc operated in nitrogen. Dynamic current-voltage characteristics and transient phenomena of steady state formation during the spark ignition phase are studied. The arc time-constant for free decay is computed and compared with approximate analytical results. It is found that for fixed initial conditions, the arc response to the variable applied voltage is several times longer than the arc time-constant for free decay. (author) 4 figs., 11 refs

  16. The Detection and Statistics of Giant Arcs Behind CLASH Clusters

    CERN Document Server

    Xu, Bingxiao; Meneghetti, Massimo; Seitz, Stella; Zitrin, Adi; Merten, Julian; Maoz, Dani; Frye, Brenda; Umetsu, Keiichi; Zheng, Wei; Bradley, Larry; Vega, Jesus; Koekemoer, Anton

    2015-01-01

    We developed an algorithm to find and characterize gravitationally lensed galaxies (arcs) to perform a comparison of the observed and simulated arc abundance. Observations are from the Cluster Lensing And Supernova survey with Hubble (CLASH). Simulated CLASH images are created using the MOKA package and also clusters selected from the high resolution, hydrodynamical simulations, MUSIC, over the same mass and redshift range as the CLASH sample. The algorithm' s arc elongation accuracy, completeness and false positive rate are determined and used to compute an estimate of the true arc abundance. We derive a lensing efficiency of $4 \\pm 1$ arcs (with length $\\ge 6"$ and length-to-width ratio $\\ge 7$) per cluster for the X-ray selected CLASH sample, $4 \\pm 1$ arcs per cluster for the MOKA simulated sample and $3 \\pm 1$ arcs per cluster for the MUSIC simulated sample. The observed and simulated arc statistics are in full agreement. We measure the photometric redshifts of all detected arcs and find a median redshif...

  17. Fast Arc-Annotated Subsequence Matching in Linear Space

    CERN Document Server

    Bille, Philip

    2009-01-01

    An arc-annotated string is a string of characters, called bases, augmented with a set of pairs, called arcs, each connecting two bases. Given arc-annotated strings $P$ and $Q$ the arc-preserving subsequence problem is to determine if $P$ can be obtained from $Q$ by deleting bases from $Q$. Whenever a base is deleted any arc with an endpoint in that base is also deleted. Arc-annotated strings where the arcs are "nested" are a natural model of RNA molecules that captures both the primary and secondary structure of these. The arc-preserving subsequence problem for nested arc-annotated strings is basic primitive for investigating the function of RNA molecules. Gramm et al. [ACM Trans. Algorithms 2006] gave an algorithm for this problem using $O(nm)$ time and space, where $m$ and $n$ are the lengths of $P$ and $Q$, respectively. In this paper we present a new algorithm using $O(nm)$ time and $O(n + m)$ space, thereby matching the previous time bound while significantly reducing the space from a quadratic term to l...

  18. Analisis dan Reduksi Bahaya ARC Flash pada Sistem Kelistrikan

    Directory of Open Access Journals (Sweden)

    Firman Aji Prasongko

    2012-09-01

    Full Text Available Upaya terakhir untuk menghitung bahaya yang berhubungan dengan potensi bahaya arc flash bergantung pada proteksi arus lebih untuk menghilangkan kondisi saat diberi gangguan. Efektivitas berbagai perangkat ditentukan oleh clearing time terkait dengan gangguan arus maksimum yang ada untuk setiap lokasi sistem. Industri komersial mulai melakukan prosedur pelabelan arc flash dan mulai mengenali pencegahan arc flash sebagai bagian dari program safety, perhitungan current method memungkinkan untuk menghitung incident energy (cal/cm² terkait dengan gangguan maksimum tiga phasa. Kesalahan terbanyak adalah besaran arus kurang dari besaran arus tiga phasa maksimum. Dalam Tugas Akhir ini akan dibahas perhitungan energy dan durasi lama terjadinya arc flash pada system kelistrikan pada electrical room.

  19. Titanium or zirconium reduction process by arc heater

    International Nuclear Information System (INIS)

    A process is provided for the reduction of a refractory metal such as zirconium or titanium from its chloride salt. An electric arc is struck in the reaction chamber, and the arc is blown into an elongated arc stream by a pressurized gas. An alkali metal or alkaline earth metal, for instance sodium or magnesium, is fed into the arc stream, as well as a quantity of the metal chloride. The alkali metal or alkaline earth metal chloride thus formed is volatile and separates from the liquid elemental metal, which flows into an associated receptacle

  20. Measurement of total ion flux in vacuum Arc discharges

    OpenAIRE

    Anders, Andre; Oks, Efim M.; Yushkov, Georgy Yu.; Brown, Ian G.

    2004-01-01

    A vacuum arc ion source was modified allowing us to collect ions from arc plasma streaming through an anode mesh. The mesh had a geometric transmittance of 60 percent, which was taken into account as a correction factor. The ion current from twenty-two cathode materials was measured at an arc current of 100 A. The ion current normalized by the arc current was found to depend on the cathode material, with valuesin the range from 5 percent to 11 percent. The normalized ion current is gener...

  1. Community Structure Comparisons of Hydrothermal Vent Microbial Mats Along the Mariana Arc and Back-arc

    Science.gov (United States)

    Hager, K. W.; Fullerton, H.; Moyer, C. L.

    2015-12-01

    Hydrothermal vents along the Mariana Arc and back-arc represent a hotspot of microbial diversity that has not yet been fully recognized. The Mariana Arc and back-arc contain hydrothermal vents with varied vent effluent chemistry and temperature, which translates to diverse community composition. We have focused on iron-rich sites where the dominant primary producers are iron oxidizing bacteria. Because microbes from these environments have proven elusive in culturing efforts, we performed culture independent analysis among different microbial communities found at these hydrothermal vents. Terminal-restriction fragment length polymorphism (T-RFLP) and Illumina sequencing of small subunit ribosomal gene amplicons were used to characterize community members and identify samples for shotgun metagenomics. Used in combination, these methods will better elucidate the composition and characteristics of the bacterial communities at these hydrothermal vent systems. The overarching goal of this study is to evaluate and compare taxonomic and metabolic diversity among different communities of microbial mats. We compared communities collected on a fine scale to analyze the bacterial community based on gross mat morphology, geography, and nearby vent effluent chemistry. Taxa richness and evenness are compared with rarefaction curves to visualize diversity. As well as providing a survey of diversity this study also presents a juxtaposition of three methods in which ribosomal small subunit diversity is compared with T-RFLP, next generation amplicon sequencing, and metagenomic shotgun sequencing.

  2. Processes of energy exchange between blasted electric arc and surrounding gas in arc heater channel

    Czech Academy of Sciences Publication Activity Database

    Heinz, J.; Šenk, J.; Hrabovský, Milan

    2002-01-01

    Roč. 52, supplement D (2002), s. 583. ISSN 0011-4626. [Symposium on Plasma Physics and Technology/20th./. Prague, 10.06.2002-13.06.2002] Institutional research plan: CEZ:AV0Z2043910 Keywords : electric arc , energy exchance, heater Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.311, year: 2002

  3. Scaling of structural failure

    Energy Technology Data Exchange (ETDEWEB)

    Bazant, Z.P. [Northwestern Univ., Evanston, IL (United States); Chen, Er-Ping [Sandia National Lab., Albuquerque, NM (United States)

    1997-01-01

    This article attempts to review the progress achieved in the understanding of scaling and size effect in the failure of structures. Particular emphasis is placed on quasibrittle materials for which the size effect is complicated. Attention is focused on three main types of size effects, namely the statistical size effect due to randomness of strength, the energy release size effect, and the possible size effect due to fractality of fracture or microcracks. Definitive conclusions on the applicability of these theories are drawn. Subsequently, the article discusses the application of the known size effect law for the measurement of material fracture properties, and the modeling of the size effect by the cohesive crack model, nonlocal finite element models and discrete element models. Extensions to compression failure and to the rate-dependent material behavior are also outlined. The damage constitutive law needed for describing a microcracked material in the fracture process zone is discussed. Various applications to quasibrittle materials, including concrete, sea ice, fiber composites, rocks and ceramics are presented.

  4. Preparing for Failure

    International Nuclear Information System (INIS)

    Risk management is one of the most complex project management processes, requiring rigorous management and discipline. Unfortunately, for many organizations, the risk management process has become contaminated by poor management practices, an absence of meaningful risk assessments, meaningless risk event descriptions, incomplete and vague risk impact analyses, poor follow through on risk mitigation activities and a general lack of attention to accuracy, completeness and quality. At this point, the risk register, instead of being a key tool used by the organization to systematically identify and eliminate risk, while exploiting opportunities, has become a list of pre-prepared excuses based on the repeat of failures encountered on past projects. However, organizations are not condemned to repeat past failures. By returning to the basics of risk management, and through the application of some basic management guidelines, the risk register-instead of being an 'Excuse Register' - can become the cornerstone of a comprehensive risk management program to promote a systematic, pro-active approach within an organization that will result in accomplishing mitigation activities, reducing risk and gaining advantage through opportunities. (authors)

  5. Making and breaking an island arc: A new perspective from the Oligocene Kyushu-Palau arc, Philippine Sea

    Science.gov (United States)

    Ishizuka, Osamu; Taylor, Rex N.; Yuasa, Makoto; Ohara, Yasuhiko

    2011-05-01

    The Kyushu-Palau Ridge (KPR) is a 2600 km long remnant island arc that is separated from the active Izu-Bonin-Mariana (IBM) arc by a series of spreading and rift basins. We present 40Ar/39Ar ages and geochemical data for the entire length of the Kyushu-Palau arc as well as for the conjugate arc which is stranded within the IBM fore arc. New 40Ar/39Ar ages indicate that the KPR was active between 25 and 48 Ma, but the majority of the exposed volcanism occurred in the final phase, between 25 and 28 Ma. Rifting of the Kyushu-Palau arc to form the Shikoku and Parece Vela basins occurred simultaneously along the length of the arc (circa 25 Ma), and at a similar distance from the trench. Unlike the IBM, the KPR has only limited systematic along-arc geochemical trends. Two geochemical components within the KPR indicate an origin in the suprasubduction mantle. First, EM-1-like lavas are identified in a restricted section of the arc, suggesting a localized heterogeneity. Second, EM-2-like arc volcanoes formed on juvenile West Philippine Basin crust, potentially reflecting ingress of mantle from the then active EM-2 province which lies in the west. Another geochemical heterogeneity is found at the KPR-Daito Ridge intersection where the arc developed on preexisting Cretaceous Daito Ridge crust. The geochemical characteristics at this intersection likely result from the involvement of sub-Daito Ridge lithospheric mantle. Subduction flux beneath the KPR generally matches post-45 Ma Eocene/Oligocene lavas in the IBM fore arc, involving fluids and melts derived from altered igneous crust.

  6. Argon arc welding of 12Kh18N10T tubes with constricted arc controlled by magnetic fields

    International Nuclear Information System (INIS)

    Agon arc welding of 12Kh18N10T steel pipes by compressed magneto-monitored arc is reported. The arc and the movement of metal in the bath has been performed by simultaneous application of a stationary and a variable magnetic field. The method provides for 2-2.5 times quicker welding thanks to better impact of the plasma flow on the edges being welded

  7. Media effects on nanobrass arc fabrications

    Energy Technology Data Exchange (ETDEWEB)

    Kassaee, M.Z. [Department of Chemistry, Tarbiat Modares University, P.O. Box 14115-175, Tehran (Iran, Islamic Republic of)], E-mail: kassaeem@modares.ac.ir; Motamedi, E.; Majdi, M.; Cheshmehkani, A.; Soleimani-Amiri, S. [Department of Chemistry, Tarbiat Modares University, P.O. Box 14115-175, Tehran (Iran, Islamic Republic of); Buazar, F. [Department of Chemistry, Tarbiat Modares University, P.O. Box 14115-175, Tehran (Iran, Islamic Republic of); Department of Marine Chemistry, Khorramshahr University of Nautical Sciences and Technologies, Khorramshahr (Iran, Islamic Republic of)

    2008-04-03

    Brass rods (3 mm x 30 mm) are directly converted into brass nanoparticles through a modified arc method, at 100 A, and in five different media. The X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM) data show strong dependence of nanoparticle sizes and their compositions on the media employed. In distilled water, both nanobrass (30 nm) and nano-Cu/ZnO (18 nm) are produced in comparable quantities. In gaseous nitrogen merely nanobrass (49 nm) is observed, in a high yield. In contrast, a very low yield of nanoproduct(s) is encountered in liquid nitrogen. In the open air, nanobrass (75 nm) is formed along with traces of ZnO. In ethylene glycol, nanobrass (108 nm) is formed as the major product along with a nanoalloy of CuZn{sub 5} (25 nm). Among these, distilled water proved to be the medium of choice for the arc synthesis of nanobrass.

  8. PSYCHOSOMATIC "ARC" IN THE PSYCHOTHERAPEUTIC PRACTICE

    Directory of Open Access Journals (Sweden)

    Ivanka Boncheva

    2012-11-01

    Full Text Available The psychoneuroimmunology, the new brain science and the endocrinology today show a lot of results, with which symptoms are better to understand. The psychotherapeutic practice shows the ways to influence them by encoding the levels of bounding between the physical symptom and the psychological condition. The aim of the study was to show the encoding of the psychosomatic arc within a real psychotherapeutic contact. 59 psychotherapeutic cases are followed. 33 of them were with somatoform disorders and 26 with chronic psychosomatic diseases. Every patient has minimum 12 psychotherapeutic sessions. The treatment is provided on the base of the 5 levels model of the positive psychotherapy.We ascertain the following:1. The most significant moment in the arise of such symptomatic is the gained past experience - "vital concepts"; "coping strategies";2. Unlocking moment for the arise of the affection is the fixed emotion - fear, aggression or depression, specific for the particular morbid pictures;3. Showing the connection between symptom and fixed emotion by the technique "positive interpretation", which unlocks the process of changingThis shows that the psychotherapeutic help is possible only if the patient rethink the psychosomatic arc. Showing the connections between the content of the unconscious, the fixed emotion in behavioral models and the symptom gives the impetus to change.

  9. Development of circuit model for arcing on solar panels

    International Nuclear Information System (INIS)

    The increased requirements of payload capacity of the satellites have resulted in much higher power requirements of the satellites. In order to minimize the energy loss during power transmission due to cable loss, use of high voltage solar panels becomes necessary. When a satellite encounters space plasma it floats negatively with respect to the surrounding space plasma environment. At high voltage, charging and discharging on solar panels causes the power system breakdown. Once a solar panel surface is charged and potential difference between surface insulator and conductor exceeds certain value, electrostatic discharge (ESD) may occur. This ESD may trigger a secondary arc that can destroy the solar panel circuit. ESD is also called as primary or minor arc and secondary is called major arc. The energy of minor arc is supplied by the charge stored in the coverglass of solar array and is a pulse of typically several 100 ns to several 100 μs duration. The damage caused by minor arc is less compared to major arcs, but it is observed that the minor arc is cause of major arc. Therefore it is important to develop an understanding of minor arc and mitigation techniques. In this paper we present a linear circuit analysis for minor arcs on solar panels. To study arcing event, a ground experimental facility to simulate space plasma environment has been developed at Facilitation Centre for Industrial Plasma Technologies (Institute for Plasma Research) in collaboration with Indian Space Research Organization's ISRO Satellite Technology Centre (ISAC). A linear circuit model has been developed to explain the experimental results by representing the coverglass, solar cell interconnect and wiring by an LCR circuit and the primary arc by an equivalent LR circuit. The aim of the circuit analysis is to predict the arc current which flows through the arc plasma. It is established from the model that the current depends on various parameters like potential difference between insulator

  10. Modeling of thermal plasma arc technology FY 1994 report

    Energy Technology Data Exchange (ETDEWEB)

    Hawkes, G.L.; Nguyen, H.D.; Paik, S.; McKellar, M.G.

    1995-03-01

    The thermal plasma arc process is under consideration to thermally treat hazardous and radioactive waste. A computer model for the thermal plasma arc technology was designed as a tool to aid in the development and use of the plasma arc-Joule beating process. The value of this computer model is to: (a) aid in understanding the plasma arc-Joule beating process as applied to buried waste or exhumed buried waste, (b) help design melter geometry and electrode configuration, (c) calculate the process capability of vitrifying waste (i.e., tons/hour), (d) develop efficient plasma and melter operating conditions to optimize the process and/or reduce safety hazards, (e) calculate chemical reactions during treatment of waste to track chemical composition of off-gas products, and composition of final vitrified waste form and (f) help compare the designs of different plasma-arc facilities. A steady-state model of a two-dimensional axisymmetric transferred plasma arc has been developed and validated. A parametric analysis was performed that studied the effects of arc length, plasma gas composition, and input power on the temperatures and velocity profiles of the slag and plasma gas. A two-dimensional transient thermo-fluid model of the US Bureau of Mines plasma arc melter has been developed. This model includes the growth of a slag pool. The thermo-fluid model is used to predict the temperature and pressure fields within a plasma arc furnace. An analysis was performed to determine the effects of a molten metal pool on the temperature, velocity, and voltage fields within the slag. A robust and accurate model for the chemical equilibrium calculations has been selected to determine chemical composition of final waste form and off-gas based on the temperatures and pressures within the plasma-arc furnace. A chemical database has been selected. The database is based on the materials to be processed in the plasma arc furnaces.

  11. Modeling of thermal plasma arc technology FY 1994 report

    International Nuclear Information System (INIS)

    The thermal plasma arc process is under consideration to thermally treat hazardous and radioactive waste. A computer model for the thermal plasma arc technology was designed as a tool to aid in the development and use of the plasma arc-Joule beating process. The value of this computer model is to: (a) aid in understanding the plasma arc-Joule beating process as applied to buried waste or exhumed buried waste, (b) help design melter geometry and electrode configuration, (c) calculate the process capability of vitrifying waste (i.e., tons/hour), (d) develop efficient plasma and melter operating conditions to optimize the process and/or reduce safety hazards, (e) calculate chemical reactions during treatment of waste to track chemical composition of off-gas products, and composition of final vitrified waste form and (f) help compare the designs of different plasma-arc facilities. A steady-state model of a two-dimensional axisymmetric transferred plasma arc has been developed and validated. A parametric analysis was performed that studied the effects of arc length, plasma gas composition, and input power on the temperatures and velocity profiles of the slag and plasma gas. A two-dimensional transient thermo-fluid model of the US Bureau of Mines plasma arc melter has been developed. This model includes the growth of a slag pool. The thermo-fluid model is used to predict the temperature and pressure fields within a plasma arc furnace. An analysis was performed to determine the effects of a molten metal pool on the temperature, velocity, and voltage fields within the slag. A robust and accurate model for the chemical equilibrium calculations has been selected to determine chemical composition of final waste form and off-gas based on the temperatures and pressures within the plasma-arc furnace. A chemical database has been selected. The database is based on the materials to be processed in the plasma arc furnaces

  12. Influence of the vacuum-arc source configuration and arc discharge parameters on the evolution and location of arc spots on the cathode surface

    OpenAIRE

    J. Walkowicz; J. Smolik; Z. Słomka; B. Kułakowska-Pawlak; W. Żyrnicki

    2009-01-01

    Purpose: The paper presents investigations of the evolution, structure and location of arc spots on the cathode frontal surfaces of two types of industrial arc sources.Design/methodology/approach: The temporal behaviour of cathode spots was recorded with the use of a fast CCD camera. The experiments were performed at four values of arc current, nine compositions of the process atmosphere N2+C2H2 and three pressure ranges of the process atmosphere.Findings: The analysis of the recorded picture...

  13. Failure analysis of buried tanks

    International Nuclear Information System (INIS)

    Failure of a buried tank can be hazardous. Failure may be a leak through which product is lost from the tank; but also through which contamination can occur. Failures are epidemic -- because buried tanks are out of sight, but also because designers of buried tanks have adopted analyses developed for pressure tanks. So why do pressure tanks fail when they are buried? Most failures of buried tanks are really soil failures. Soil compresses, or slips, or liquefies. Soil is not only a load, it is a support without which the tank deforms. A high water table adds to the load on the tank. It also reduces the strength of the soil. Based on tests, structural analyses are proposed for empty tanks buried in soils of various quality, with the water table at various levels, and with internal vacuum. Failure may be collapse tank. Such collapse is a sudden, audible inversion of the cylinder when the sidefill soil slips. Failure may be flotation. Failure may be a leak. Most leaks are fractures in the welds in overlap seams at flat spots. Flat spots are caused by a hard bedding or a heavy surface wheel load. Because the tank wall is double thick at the overlap, shearing stress in the weld is increased. Other weld failures occur when an end plate shears down past a cylinder; or when the tank is supported only at its ends like a beam. These, and other, failures can be analyzed with justifiable accuracy using basic principles of mechanics of materials. 10 figs

  14. Insomnia Self-Management in Heart Failure

    Science.gov (United States)

    2016-05-11

    Cardiac Failure; Heart Failure; Congestive Heart Failure; Heart Failure, Congestive; Sleep Initiation and Maintenance Disorders; Chronic Insomnia; Disorders of Initiating and Maintaining Sleep; Fatigue; Pain; Depressive Symptoms; Sleep Disorders; Anxiety

  15. Fatigue assessment of a double submerged arc welded gas pipeline

    Energy Technology Data Exchange (ETDEWEB)

    Fazzini, Pablo; Otegui, Jose Luis [Universidad Nacional Mar del Plata, Mar del Plata (Argentina). Instituto de Ciencia y Tecnologia de Materiales (INTEMA); Teutonico, Mauricio; Manfredi, Carlos [GIE S.A., Mar del Plata (Argentina)

    2005-07-01

    An uncommon blowout in a 24'' diameter, 7 mm thick API 5L X52 gas pipeline was due to fracture at the longitudinal double submerged arc weld. Oddly enough for gas pipelines, it was found that fatigue cracks had propagated from a large embedded weld defect of lack of fusion resulting from severe geometrical mismatch between inner and outer weld passes. What makes this failure particularly interesting is that: previous in line inspections failed to detect any defect, no evidence of third party damage was found, and very few large pressure cycles had been recorded during the last 5 years of service, which were believed to be representative of the entire service life of the pipeline. Fatigue tests were carried out to characterize propagation of fatigue cracks in weld metal, it was found that a large Paris exponent made the few large amplitude cycles most contributing to crack propagation. Crack growth path and striation patterns were studied. Fatigue growth was modelled by integrating experimental results and by extrapolating striation spacing in the fracture surface of the failed pipe. Crack growth path and striation patterns were studied. It was found that microstructure discontinuities govern propagation at low {delta}K, but one striation per cycle was produced at large {delta}K, due to a mostly ductile propagation mode. Fatigue growth was modelled by integrating experimental results and by extrapolating striation spacing in the fracture surface of the failed pipe. It was found that in the early life of the line many more large pressure cycles than expected had occurred. Good correspondence between predicted and actual fatigue lives was in this way obtained (author)

  16. An analytical model for interactive failures

    International Nuclear Information System (INIS)

    In some systems, failures of certain components can interact with each other, and accelerate the failure rates of these components. These failures are defined as interactive failure. Interactive failure is a prevalent cause of failure associated with complex systems, particularly in mechanical systems. The failure risk of an asset will be underestimated if the interactive effect is ignored. When failure risk is assessed, interactive failures of an asset need to be considered. However, the literature is silent on previous research work in this field. This paper introduces the concepts of interactive failure, develops an analytical model to analyse this type of failure quantitatively, and verifies the model using case studies and experiments

  17. Copeptin in Heart Failure.

    Science.gov (United States)

    Balling, Louise; Gustafsson, Finn

    2016-01-01

    Heart failure (HF) is one of the most common causes of hospitalization and mortality in the modern Western world and an increasing proportion of the population will be affected by HF in the future. Although HF management has improved quality of life and prognosis, mortality remains very high despite therapeutic options. Medical management consists of a neurohormonal blockade of an overly activated neurohormonal axis. No single marker has been able to predict or monitor HF with respect to disease progression, hospitalization, or mortality. New methods for diagnosis, monitoring therapy, and prognosis are warranted. Copeptin, a precursor of pre-provasopressin, is a new biomarker in HF with promising potential. Copeptin has been found to be elevated in both acute and chronic HF and is associated with prognosis. Copeptin, in combination with other biomarkers, could be a useful marker in the monitoring of disease severity and as a predictor of prognosis and survival in HF. PMID:26975969

  18. Component failure data handbook

    Energy Technology Data Exchange (ETDEWEB)

    Gentillon, C.D.

    1991-04-01

    This report presents generic component failure rates that are used in reliability and risk studies of commercial nuclear power plants. The rates are computed using plant-specific data from published probabilistic risk assessments supplemented by selected other sources. Each data source is described. For rates with four or more separate estimates among the sources, plots show the data that are combined. The method for combining data from different sources is presented. The resulting aggregated rates are listed with upper bounds that reflect the variability observed in each rate across the nuclear power plant industry. Thus, the rates are generic. Both per hour and per demand rates are included. They may be used for screening in risk assessments or for forming distributions to be updated with plant-specific data.

  19. Artificial neural networks in predicting current in electric arc furnaces

    International Nuclear Information System (INIS)

    The paper presents a study of the possibility of using artificial neural networks for the prediction of the current and the voltage of Electric Arc Furnaces. Multi-layer perceptron and radial based functions Artificial Neural Networks implemented in Matlab were used. The study is based on measured data items from an Electric Arc Furnace in an industrial plant in Romania

  20. Arc generation from sputtering plasma-dielectric inclusion interactions

    CERN Document Server

    Wickersham, C E J; Fan, J S

    2002-01-01

    Arcing during sputter deposition and etching is a significant cause of particle defect generation during device fabrication. In this article we report on the effect of aluminum oxide inclusion size, shape, and orientation on the propensity for arcing during sputtering of aluminum targets. The size, shape, and orientation of a dielectric inclusion plays a major role in determining the propensity for arcing and macroparticle emission. In previous studies we found that there is a critical inclusion size required for arcing to occur. In this article we used high-speed videos, electric arc detection, and measurements of particle defect density on wafers to study the effect of Al sub 2 O sub 3 inclusion size, shape, and orientation on arc rate, intensity, and silicon wafer particle defect density. We found that the cross-sectional area of the inclusion exposed to the sputtering plasma is the critical parameter that determines the arc rate and rate of macroparticle emission. Analysis of the arc rate, particle defect...

  1. What makes an electric welding arc perform its required function

    Energy Technology Data Exchange (ETDEWEB)

    Correy, T.B.

    1982-09-01

    The physics of direct current and alternating current welding arcs, the heat transfer of direct current welding arcs, the characteristics of dc welding and ac welding power supplies and recommendations for the procurement and maintenance of precision power supplies are discussed. (LCL)

  2. Improving the Mach number capabilities of arc driven shock tubes

    Science.gov (United States)

    Johnson, J. A., III; Santiago, J.; I, L.

    1980-01-01

    New systematic trends in one of the performance parameters of pressure loaded arc driven shock tubes have been determined. For a given configuration, the Mach number increases with the cube root of capacitor energy; however, the initial driver gas pressure is relatively unimportant. A qualitative model based on the assumption of Joule-preheating by the arc discharge is discussed.

  3. The design and properties of arc heaters for gas heating

    Czech Academy of Sciences Publication Activity Database

    Šenk, J.; Jakubová, I.; Chumak, Oleksiy

    Bologna : Universitá di Bologna, 2012. PS2.16-PS2.16. ISBN N. [European Plasma Conference, HTTP -12. 24.06.2012-29.06.2012, Bologna] Institutional research plan: CEZ:AV0Z20430508 Keywords : Electric arc * thermal plasma * gas heater * arc plasma torch Subject RIV: BL - Plasma and Gas Discharge Physics

  4. A sustained-arc ignition system for internal combustion engines

    Science.gov (United States)

    Birchenough, A. G.

    1977-01-01

    A sustained-arc ignition system was developed for internal combustion engines. It produces a very-long-duration ignition pulse with an energy in the order of 100 millijoules. The ignition pulse waveform can be controlled to predetermined actual ignition requirements. The design of the sustained-arc ignition system is presented in the report.

  5. Theoretical-experiment investigation of intesively blasted electric arc

    Czech Academy of Sciences Publication Activity Database

    Hrabovský, Milan; Heinz, J.; Jakubová, I.; Šenk, J.

    Toulous, 2004 - (Bordage, M.; Gleizes, A.; Gonzales, J.), s. 129-132 [International Conference on Gas Discharges and their Applications - GD 2004 /15./. Toulouse (FR), 05.09.2004-10.09.2004] R&D Projects: GA AV ČR IAA1057202 Keywords : electric arc, plasma generator, arc heater, thermal plasma, modelling Subject RIV: BL - Plasma and Gas Discharge Physics

  6. Variable-Polarity Plasma Arc Welding Of Alloy 2219

    Science.gov (United States)

    Walsh, Daniel W.; Nunes, Arthur C., Jr.

    1989-01-01

    Report presents results of study of variable-polarity plasma arc (VPPA) welding of aluminum alloy 2219. Consists of two parts: Examination of effects of microsegregation and transient weld stress on macrosegregation in weld pool and, electrical characterization of straight- and reverse-polarity portions of arc cycle.

  7. A review of vacuum ARC ion source research at ANSTO

    International Nuclear Information System (INIS)

    The authors talk briefly describes the history and current status of vacuum arc ion source research at the Australian Nuclear Science and Technology Organization (ANSTO). In addition, the author makes some mention of the important role of previous Vacuum Arc Ion Source Workshops in fostering the development of this research field internationally. During the period 1986 -89, a type of plasma centrifuge known as a vacuum arc centrifuge was developed at ANSTO as part of a research project on stable isotope separation. In this device, a high current vacuum arc discharge was used to produce a metal plasma which was subsequently rotated in an axial magnetic field. The high rotational speeds (105 - 106 rad sec-1) achievable with this method produce centrifugal separation of ions with different mass:charge ratios such as isotopic species. The first portent of things to come occurred in 1985 when Dr. Ian Brown visited ANSTO's Lucas Heights Research Laboratories and presented a talk on the metal vapour vacuum arc (MEVVA) ion source which had only recently been invented by Brown and co-workers, J. Galvin and R. MacGill, at Lawrence Berkeley Laboratory. For those of us involved in vacuum arc centrifuge research, this was an exciting development primarily because the metal vapour vacuum arc plasma source was common to both devices. Thus, a type of arc, which had since the 1930's been extensively investigated as a means of switching high current loads, had found wider application as a useful plasma source

  8. New sizes of complete arcs in PG(2,q)

    CERN Document Server

    Davydov, Alexander A; Marcugini, Stefano; Pambianco, Fernanda

    2010-01-01

    New upper bounds on the smallest size of a complete arc in the projective plane PG(2,q) are obtained for 841<= q <= 2333. The bounds are obtained by computer search using a randomized greedy algorithm. Also new sizes of complete arcs are presented.

  9. Petrographic and Geochemical Investigation of Andesitic Arc Volcanism: Mount Kerinci, Sunda Arc, Indonesia

    Science.gov (United States)

    Tully, M.; Saunders, K.; Troll, V. R.; Jolis, E.; Muir, D. D.; Deegan, F. M.; Budd, D. A.; Astbury, R.; Bromiley, G. D.

    2014-12-01

    Present knowledge of the chain of dominantly andesitic volcanoes, which span the Sumatran portion of the Sunda Arc is extremely limited. Previous studies have focused on Toba and Krakatau, although over 13 further volcanic edifices are known. Several recent explosive eruptions in Sumatra such as that of Mt. Sinabung, 2014, have highlighted the potential hazard that these volcanoes pose to the local and regional communities. Mount Kerinci, is one of the most active of the volcanoes in this region, yet little is known about the petrogenesis of the magma by which it is fed. Kerinci is located approximately mid-way between Toba in the North and Krakatau in the south. Along arc variations are observed in the major, minor and trace elements of whole rock analyses. However, bulk rock approaches produce an average chemical composition for a sample, potentially masking important chemical signatures. In-situ micro-analytical analysis of individual components of samples such as melt inclusions, crystals and groundmass provides chemical signatures of individual components allowing the evolution of volcanic centres to be deciphered in considerably more detail. Examination of whole rock chemistry indicates its location may be key to unravelling the petrogenesis of the arc as significant chemical changes occur between Kerinci and Kaba, 250 km to the south. Kerinci samples are dominantly porphyritic with large crystals of plagioclase, pyroxene and Fe-Ti oxides, rare olivine crystals are observed. Plagioclase and pyroxene crystals are chemically zoned and host melt inclusions. Multiple plagioclase populations are observed. A combination of in-situ micro-analysis techniques will be used to characterise the chemical composition of melt inclusions and crystals. These data can be used along with extant geothermobarometric models to help determine the magma source, storage conditions and composition of the evolving melt. Integration of the findings from this study with existing data for

  10. A method to determine arc position in ICRF systems

    Energy Technology Data Exchange (ETDEWEB)

    D’Inca, R., E-mail: rodolphe.dinca@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Garching (Germany); Polozhiy, K.; Eckert, B.; Siegel, G. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Garching (Germany); Noterdaeme, J.-M. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Garching (Germany); EESA Department, Gent University (Belgium)

    2013-10-15

    Highlights: ► We show that the voltage noise characteristic of an arc in an ICRF system is due to the propagation and reflections of an electromagnetic pulse emitted by this arc. ► A simplified RF model of an arc in a testbed representative of an ICRF system is developed to see the effect of its location on the voltage noise it emits. ► The model is compared with the results on the testbed for arcs occurring at two locations: one can be determined precisely, the other with a decreased accuracy. -- Abstract: The study of arcs on ICRF systems has mainly focused on the development of fast detectors to detect a breakdown, independently from its position, before they can damage the components [1]. However, the ability to localize an arc is also an important factor: arcs can be the sign of a defect and if they occur at the same location, they give a good indication of the position of this defect without having to use intrusive diagnostics like optical fibers. We present here a method to find the position of arcs based on the analysis of their high-frequency noise. Arcs are indeed fast transient which excite frequencies in the MHz range. The SHAD system reacts on the integral value of this noise signal to detect the development of arcs. But a further investigation of this signal shows detailed features like splittings and chirpings of the frequency peaks which give more information on the source of the breakdown: at its birth, the arc emits a short electromagnetic pulse of several nanoseconds that propagates inside the ICRF system; this pulse is reflected by components like the antenna, the stub tuners or the generators back to the arc thereby changing its boundary conditions. This resonance between the arc and the ICRF system can be measured and the time of propagation of the pulse gives useful data on the position of the breakdown. We have carried out tests on the Manipulator eXPeriment (a testbed to artificially create arcs in a representative ICRF system) and

  11. Investigation of optimal control system for arc spraying

    Institute of Scientific and Technical Information of China (English)

    Li Heqi; Li Chunxu

    2005-01-01

    Arc-voltage feedback PID ( Proportional plus Integral plus Differential) controller and arc-current feedback PID controller are designed with an algorithm of discrete PID. In order to realize parameters optimization and adaptation of the arc-spraying process and to reduce blindness in selecting process parameters, a serial communication interface between PC and MCU (Micro Control Unit) is designed so that on-line modification of the PID control parameters is implemented. A genetic algorithm is adopted to optimize PID control parameters. Meanwhile, the error between the actual value and the setting value of spraying current is selected as the judgment criterion to determine the adaptability for the algorithm. The best optimal population of PID control parameters can be obtained, so that the optimal controlling in arc-spraying process is realized and an excellent coating of arc-spraying is obtained.

  12. Thin free arcs in alkali-seeded noble gases

    International Nuclear Information System (INIS)

    Thin arcs (as, for instance, those observed in noble gas magnetohydrodynamic generators) are analyzed. The spatial distributions of the important plasma quantities are calculated by solving the appropriate balance equations. Solutions are obtained for cesium-seeded argon as well as for pure argon. The solutions yield characteristic radial dimensions which are in agreement with known experimental values. The effects of variations of important arc parameters are discussed in the case of cesium-seeded argon. It appears that the effects of the parameter variations can be explained to a large extent by a simplified expression for the radial dimension of the arc. Deviation from local thermodynamic equilibrium is only significant in the outer region of the arc and has practically no influence on the arc properties

  13. High efficiency infrared antireflection coatings (ARCs) for space optics

    Science.gov (United States)

    Nagendra, C. L.; Thutupalli, G. K. M.; Mohan, S.

    1989-05-01

    The development of non-quarter-wave IR ARCs for the Ge optics of space electrooptic hardware is described. A novel design-optimization method is applied in which the geometrical thicknesses of the ARC layers are calculated analytically (as explained by Nagendra, 1987). Two ARCs are developed: a three-layer system (ThF4/Ge/ThF4) for use at 7-12 microns and a two-layer system (CdTe/CdSe) for 14-16 microns. The ARCs are deposited in a vacuum-evaporation facility and subjected to optical and durability testing. The results are presented in graphs, and it is demonstrated that the ARCs are durable and transparent over the desired wavelength range and have spectral transmittance characteristics in good agreement with the theoretically predicted values.

  14. Investigation on the stepping arc stud welding process

    Institute of Scientific and Technical Information of China (English)

    Chi Qiang; Zhang Jianxun; Fu Jifei; Zhang Youquan

    2005-01-01

    Through the investigation on traditional arc stud welding process, a new welding gun and its control system were developed in this paper. The stepping arc stud welding gun was mainly made by a stepping motor as actuating unit and a screw-driven device as moving unit. A control system with a MCS-51 single-chip microcomputer as main control component was used to realize the new stud welding procedure. This new welding process with stepping stud welding gun is named as stepping arc stud welding. In the new welding process, the stud action can be looked as constituted by some micro steps. The setting and adjusting of the stepping arc welding gun behavior parameters are accomplished independently. It is indicated from the results of process tests and bending test that the stepping arc stud welding process is practicable.

  15. Fluctuations of precipitated electron intensity in flickering auroral arcs

    International Nuclear Information System (INIS)

    This paper reports on electron spectra associated with two aurorae observed by ground-based television. One auroral arc was observed to flicker, large variations in the precipitated electron energy occurring on a time scale of 114 ms. The major variations occur at the higher energies of the 0.5--20 keV range covered by the detectors. Changes in the particle flux occur primarily in the pitch angle range 00 to 600. Analysis of the video data shows a larger variation in intensity along the lower border of the arc in keeping with the results of the electron spectra. The second arc was not observed to flicker, and the associated electron spectra and video data show no large variations in precipitated electron energy or video intensity modulation. While pitch angle distributions tend to be field-aligned in the first arc, the distributions in the second arc are nearly isotropic or peaked from 600 to 900 in the downward hemisphere

  16. Lessons Learned from EAST's Failures

    International Nuclear Information System (INIS)

    Full text: Significant progresses have been obtained on EAST tokamak partially based on lessons from its failures marked by more than 20 times leakages from PFC and 1.6 ton water inside of vacuum chamber. Lessons learned from major failures in EAST have been summarized in this paper. Major failures came from design, construction, commissioning and operation phases have been described which have been classified as imperfect design, QA control, failure of components and lack of understanding. Predictions for further risks and possible ways to mitigating these risks have been given in this paper. (author)

  17. Submersion and acute respiratory failure

    Directory of Open Access Journals (Sweden)

    Yu-Jang Su

    2014-01-01

    Conclusions: Submersion patients who are hypothermic on arrival of emergency department (ED are risky to respiratory failure and older, more hypothermic, longer hospital stay in suicidal submersion patients.

  18. New developments in electric arc furnace technologies

    Energy Technology Data Exchange (ETDEWEB)

    Samuelsson, P. [Danieli Centrome, France (France)

    1997-04-01

    Technologies are described for the flexible operation of electric arc furnaces combining various energy sources and for the improvement of the electrical behaviour of the furnace. The main part of the article deals with the post-combustion process, as a means of reducing the energy consumption and increasing the furnace productivity. The energy yield from post-combustion is evaluated and compared to operational results. Oxidizing reactions as energy source are discussed. The energy yield for post-combustion is evaluated with data from four furnaces in operation. The energy yield from post-combustion ranges from 4 to 2 kWh per Nm{sup 3} of oxygen representing a range of 4 to 18 Nm{sup 3} oxygen injected for post-combustion. (author) 2 refs.

  19. Recycling of electric arc furnace dust

    International Nuclear Information System (INIS)

    This research aims to study the process of incorporation of the metal iron in electric arc furnace dust (EAFD), from a steel mill producing long steel by liquid iron in addition to the changing temperature of 1400 degrees Celsius of EAFD 'as received', the percentage of EAFD to be added (5, 10 and 20% of initial weight of sample pig iron) and the time of withdrawal of the sample of pig iron and slag (30 minutes after the addition of EAFD). Previously, the EAFD will be characterized using the following techniques: chemical analysis, size analysis, specific surface area, Xray diffraction, scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) microanalysis. . After characterization, the EAFD will be added to the bath of liquid pig iron. It is expected that the results obtained at the end of the research allow the evaluation of the iron metal incorporation of EAFD in pig iron bath. (author)

  20. Arc modelling in SF6 circuit breakers

    International Nuclear Information System (INIS)

    The paper presents the work done by an operator, EDF and two manufacturers to improve the physical models and numerical methods used to simulate the behavior of the plasma and cold gas around it in a breaking chamber of the HV SF6 circuit breaker, during the high-current phase. This work concerns flow phenomena, in particular incorporating compressibility and the study of turbulence, the coupling between these flow phenomena and electromagnetic phenomena, and finally, radiation - which plays an essential role in energy transfer during the high-current phase. For this latter aspect, emission but also absorption were proven to play a major role, and the two were introduced into the models. The paper presents the models developed and the results obtained with them for simulation of two circuit breaker mock-ups (a double-pressure circuit breaker mock-up and a self-expanding and rotating arc circuit breaker mock-up). (author)

  1. Danarc technology for electric arc furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Samuelsson, P.; Gensini, G.; Mavridis [Danieli Centro Met, Buttrio (Italy)

    1995-06-01

    Danarc electric arc furnace technology combines high-impedance technology with bottom tuyeres for oxygen and carbon injection. Together with lance injection and wall burners for both conventional operation and post-combustion, the concept provides full flexibility in the choice of energy sources. The basic philosophy of the concept is to have efficient systems for the supply of both electrical and alternative energy. Operational results from a Danarc furnace at Ferriere Nord show that it is possible to inject high specific amounts of oxygen and carbon as a substitute for electrical energy. The electrical power supply with a fixed or saturable reactor is beneficial because of the high voltage and low current operation. High-impedance operation results in low electrode consumption, reduced electrical losses and a reduction of the supply network disturbance, ie, flicker.

  2. Is a single arc sufficient in volumetric-modulated arc therapy (VMAT) for complex-shaped target volumes?

    International Nuclear Information System (INIS)

    Purpose: To compare step-and-shoot intensity-modulated radiotherapy (ss-IMRT) with volumetric-modulated arc therapy (VMAT) for complex-shaped target volumes with a simultaneous integrated boost (SIB). Materials and methods: This retrospective planning study was based on 20 patients composed of prostate cancer (n = 5), postoperative (n = 5) or primary (n = 5) radiotherapy for pharyngeal cancer and for cancer of the paranasal sinuses (n = 5); a SIB with two or three dose levels was planned in all patients. For each patient, one ss-IMRT plan with direct-machine-parameter optimization (DMPO) and VMAT plans with one to three arcs (SmartArc technique) were generated in the Pinnacle planning system. Results: Single arc VMAT improved target coverage and dose homogeneity in radiotherapy for prostate cancer. Two and three VMAT arcs were required to achieve equivalent results compared to ss-IMRT in postoperative and primary radiotherapy for pharyngeal cancer, respectively. In radiotherapy for cancer of the paranasal sinuses, multiarc VMAT resulted in increased spread of low doses to the lenses and decreased target coverage in the region between the orbits. Conclusions: The complexity of the target volume determined whether single arc VMAT was equivalent to ss-IMRT. Multiple arc VMAT improved results compared to single arc VMAT at cost of increased delivery times, increased monitor unites and increased spread of low doses.

  3. The modelling of an SF6 arc in a supersonic nozzle: II. Current zero behaviour of the nozzle arc

    Science.gov (United States)

    Zhang, Q.; Liu, J.; Yan, J. D.; Fang, M. T. C.

    2016-08-01

    The present work (part II) forms the second part of an investigation into the behaviour of SF6 nozzle arc. It is concerned with the aerodynamic and electrical behaviour of a transient nozzle arc under a current ramp specified by a rate of current decay (di/dt) before current zero and a voltage ramp (dV/dt) after current zero. The five flow models used in part I [1] for cold gas flow and DC nozzle arcs have been applied to study the transient arc at three stagnation pressures (P 0) and two values of di/dt for the current ramp, representing a wide range of arcing conditions. An analysis of the physical mechanisms encompassed in each flow model is given with an emphasis on the adequacy of a particular model in describing the rapidly varying arc around current zero. The critical rate of rise of recovery voltage (RRRV) is found computationally and compared with test results of Benenson et al [2]. For transient nozzle arcs, the RRRV is proportional to the square of P 0, rather than to the square root of P 0 for DC nozzle arcs. The physical mechanisms responsible for the strong dependence of RRRV on P 0 have been investigated. The relative merits of the flow models employed are discussed.

  4. Lithospheric buckling and intra-arc stresses: A mechanism for arc segmentation

    Science.gov (United States)

    Nelson, Kerri L.

    1989-01-01

    Comparison of segment development of a number of arcs has shown that consistent relationships between segmentation, volcanism and variable stresses exists. Researchers successfully modeled these relationships using the conceptual model of lithospheric buckling of Yamaoka et al. (1986; 1987). Lithosphere buckling (deformation) provides the needed mechanism to explain segmentation phenomenon; offsets in volcanic fronts, distribution of calderas within segments, variable segment stresses and the chemical diversity seen between segment boundary and segment interior magmas.

  5. Simulation of the Effects of Several Factors on Arc Plasma Behavior in Low Voltage Circuit Breaker

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Taking into account the properties of the arc plasma and the electromagnetic, heat and radiative phenomena, commercial computational fluid dynamics software PHOENICS has been adapted and modified to develop the three-dimensional magneto-hydrodynamic (MHD)model of arc in a low voltage circuit breaker. The effects of the arc ignition location, venting size and gassing material on arc behavior have been investigated. The analysis of the results show that the arc velocity accelerates with the increase in the distance between arc ignition location and of the venting size, and the existence of the gassing material is beneficial to improving the arc voltage and reducing the arc temperature.

  6. Cycling of sulfur in subduction zones: The geochemistry of sulfur in the Mariana Island Arc and back-arc trough

    Science.gov (United States)

    Alt, J.C.; Shanks, Wayne C., III; Jackson, M.C.

    1993-01-01

    The sulfur contents and sulfur isotopic compositions of 24 glassy submarine volcanics from the Mariana Island Arc and back-arc Mariana Trough were determined in order to investigate the hypothesis that subducted seawater sulfur (??34S = 21???) is recycled through arc volcanism. Our results for sulfur are similar to those for subaerial arc volcanics: Mariana Arc glasses are enriched in 34S (??34S = up to 10.3???, mean = 3.8???) and depleted in S (20-290 ppm, mean = 100 ppm) relative to MORB (850 ppm S, ??34S = 0.1 ?? 0.5???). The back-arc trough basalts contain 200-930 ppm S and have ??34S values of 1.1 ?? 0.5???, which overlap those for the arc and MORB. The low sulfur contents of the arc and some of the trough glasses are attributed to (1) early loss of small amounts of sulfur through separation of immiscible sulfide and (2) later vapor-melt equilibrium control of sulfur contents and loss of sulfur in a vapor phase from sulfide-undersaturated melts near the minimum in sulfur solubility at f{hook}O2 ??? NNO (nickel-nickel oxide). Although these processes removed sulfur from the melts their effects on the sulfur isotopic compositions of the melts were minimal. Positive trends of ??34S with 87Sr 86Sr, LILE and LREE contents of the arc volcanics are consistent with a metasomatic seawater sulfur component in the depleted sub-arc mantle source. The lack of a 34S-rich slab signature in the trough lavas may be attributed to equilibration of metasomatic fluid with mantle material along the longer pathway from the slab to the source of the trough volcanics. Sulfur is likely to have been transported into the mantle wedge by metasomatic fluid derived from subducted sediments and pore fluids. Gases extracted from vesicles in arc and back-arc samples are predominantly H2O, with minor CO2 and traces of H2S and SO2. CO2 in the arc and back-arc rocks has ??13C values of -2.1 to -13.1???, similar to MORB. These data suggest that degassing of CO2 could explain the slightly lower

  7. Numerical and experimental study of heat transfers in an arc plasma. Application to TIG arc welding

    International Nuclear Information System (INIS)

    The arc welding is used for many industrial applications, especially GTA welding. Given the excellent quality of the produced welds, GTA welding is used for the majority of the interventions (repairs, joined sealing) on the French nuclear park. This work is part of a project carried out by EDF R and D which aims to simulate the whole process and builds a tool able to predict the welds quality. In this study, we focus on the development of a predictive model of the exchanged heat flux at the arc - work piece interface, responsible of the work piece fusion. The modeling of the arc plasma using the electric module of the hydrodynamics software Code Saturne R developed by EDF R and D is required. Two types of experimental tests are jointly carried out to validate this numerical model: i) on density and temperature measurements of plasma by atomic emission spectroscopy and ii) on the evaluation of the heat transfers on the work piece surface. This work also aims at demonstrate that the usual method of using an equivalent thermal source to model the welding process, can be replaced by our plasma model, without the numerous trials inherent to the usual method. (author)

  8. ArcGeomorphometry: A toolbox for geomorphometric characterisation of DEMs in the ArcGIS environment

    Science.gov (United States)

    Rigol-Sanchez, Juan P.; Stuart, Neil; Pulido-Bosch, Antonio

    2015-12-01

    A software tool is described for the extraction of geomorphometric land surface variables and features from Digital Elevation Models (DEMs). The ArcGeomorphometry Toolbox consists of a series of Python/Numpy processing functions, presented through an easy-to-use graphical menu for the widely used ArcGIS package. Although many GIS provide some operations for analysing DEMs, the methods are often only partially implemented and can be difficult to find and used effectively. Since the results of automated characterisation of landscapes from DEMs are influenced by the extent being considered, the resolution of the source DEM and the size of the kernel (analysis window) used for processing, we have developed a tool to allow GIS users to flexibly apply several multi-scale analysis methods to parameterise and classify a DEM into discrete land surface units. Users can control the threshold values for land surface classifications. The size of the processing kernel can be used to identify land surface features across a range of landscape scales. The pattern of land surface units from each attempt at classification is displayed immediately and can then be processed in the GIS alongside additional data that can assist with a visual assessment and comparison of a series of results. The functionality of the ArcGeomorphometry toolbox is described using an example DEM.

  9. Adult intestinal failure

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, J., E-mail: Jdavidson@doctors.org.u [Salford Royal Hospital, Salford (United Kingdom); Plumb, A.; Burnett, H. [Salford Royal Hospital, Salford (United Kingdom)

    2010-05-15

    Intestinal failure (IF) is the inability of the alimentary tract to digest and absorb sufficient nutrition to maintain normal fluid balance, growth, and health. It commonly arises from disease affecting the mesenteric root. Although severe IF is usually managed in specialized units, it lies at the end of a spectrum with degrees of nutritional compromise being widely encountered, but commonly under-recognized. Furthermore, in the majority of cases, the initial enteric insult occurs in non-specialist IF centres. The aim of this article is to review the common causes of IF, general principles of its management, some commoner complications, and the role of radiology in the approach to a patient with severe IF. The radiologist has a crucial role in helping provide access for feeding solutions (both enteral and parenteral) and controlling sepsis (via drainage of collections) in an initial restorative phase of treatment, whilst simultaneously mapping bowel anatomy and quality, and searching for disease complications to assist the clinicians in planning a later, restorative phase of therapy.

  10. Adult intestinal failure

    International Nuclear Information System (INIS)

    Intestinal failure (IF) is the inability of the alimentary tract to digest and absorb sufficient nutrition to maintain normal fluid balance, growth, and health. It commonly arises from disease affecting the mesenteric root. Although severe IF is usually managed in specialized units, it lies at the end of a spectrum with degrees of nutritional compromise being widely encountered, but commonly under-recognized. Furthermore, in the majority of cases, the initial enteric insult occurs in non-specialist IF centres. The aim of this article is to review the common causes of IF, general principles of its management, some commoner complications, and the role of radiology in the approach to a patient with severe IF. The radiologist has a crucial role in helping provide access for feeding solutions (both enteral and parenteral) and controlling sepsis (via drainage of collections) in an initial restorative phase of treatment, whilst simultaneously mapping bowel anatomy and quality, and searching for disease complications to assist the clinicians in planning a later, restorative phase of therapy.

  11. Getting Pumped About Heart Failure

    OpenAIRE

    Mann, Douglas L.

    2014-01-01

    Heart failure is a clinical syndrome caused by dysregulated calcium handling and abnormal cardiac pumping capacity. Whalquist et al. (2014) show that upregulation of micro-RNA25 impairs calcium handling leading to pump dysfunction, and that targeting micro-RNA25 using antisense oligonucleotides reverses pump dysfunction and improves survival in mice with heart failure.

  12. Failure Environment Analysis Tool (FEAT)

    Science.gov (United States)

    Lawler, D. G.

    1991-01-01

    Information is given in viewgraph form on the Failure Environment Analysis Tool (FEAT), a tool designed to demonstrate advanced modeling and analysis techniques to better understand and capture the flow of failures within and between elements of the Space Station Freedom (SSF) and other large complex systems. Topics covered include objectives, development background, the technical approach, SSF baseline integration, and FEAT growth and evolution.

  13. Corrosion Failures in Marine Environment

    Directory of Open Access Journals (Sweden)

    R. Krishnan

    1985-04-01

    Full Text Available This paper gives a brief description of typical marine environments and the most common form of corrosion of materials used in this environment. Some typical case histories of failures pertaining to pitting, bimetallic corrosion, dealloying, cavitation and stress corrosion cracking are illustrated as typical examples of corrosion failures.

  14. A Failure Criterion for Concrete

    DEFF Research Database (Denmark)

    Ottosen, N. S.

    1977-01-01

    A four-parameter failure criterion containing all the three stress invariants explicitly is proposed for short-time loading of concrete. It corresponds to a smooth convex failure surface with curved meridians, which open in the negative direction of the hydrostatic axis, and the trace in the devi...

  15. Intestinal failure in obstructive jaundice

    Institute of Scientific and Technical Information of China (English)

    Stelios F. Assimakopoulos; Constantine E. Vagianos; Aristides Charonis; Vassiliki N. Nikolopoulou; Chrisoula D. Scopa

    2005-01-01

    @@ TO THE EDITOR We read with great interest the article by Ding LA and LiJS, which aimed to review the current knowledge on the physiology of normal intestinal barrier function and highlight the role of intestinal failure after various injurious insults in the development of septic complications or multiple organ failure with subsequent rapid clinical deterioration or even death.

  16. Failure Rates in Introductory Programming

    DEFF Research Database (Denmark)

    Bennedsen, Jens; Caspersen, Michael Edelgaard

    2007-01-01

    It is a common conception that CS1 is a very difficult course and that failure rates are high. However, until now there has only been anecdotal evidence for this claim. This article reports on a survey among institutions around the world regarding failure rates in introductory programming courses...

  17. INFLUENCE OF VACUUM ARC PLASMA EVAPORATOR CATHODE GEOMETRY OF ON VALUE OF ADMISSIBLE ARC DISCHARGE CURRENT

    Directory of Open Access Journals (Sweden)

    I. A. Ivanou

    2015-01-01

    Full Text Available An analysis of main design parameters that determine a level of droplet formation intensity at the generating stage of plasma flow has been given in the paper. The paper considers the most widely used designs of water cooled consumable cathodes. Ti or Ti–Si and Fe–Cr alloys have been taken as a material for cathodes. The following calculated data: average ionic charge Zi for titanium plasma +1.6; for «titanium–silicon plasma» +1.2, an electronic discharge 1.6022 ⋅ 10–19 C, an ion velocity vi = 2 ⋅ 104 m/s, an effective volt energy equivalent of heat flow diverted in the cathode Uк = 12 V, temperature of erosion cathode surface Тп = 550 К; temperature of the cooled cathode surface То = 350 К have been accepted in order to determine dependence of a maximum admissible arc discharge current on cathode height. The calculations have been carried out for various values of the cathode heights hк (from 0.02 to 0.05 m. Diameter of a target cathode is equal to 0.08 m for a majority of technological plasma devices, therefore, the area of the erosion surface is S = 0.005 m2.A thickness selection for a consumable target cathode part in the vacuum arc plasma source has been justified in the paper. The thickness ensures formation of minimum drop phase in the plasma flow during arc cathode material evaporation. It has been shown that a maximum admissible current of an arc discharge is practically equal to the minimum current of stable arcing when thickness of the consumable cathode part is equal to 0.05 m. The admissible discharge current can be rather significant and ensure high productivity during coating process with formation of relatively low amount of droplet phase in the coating at small values of hк.

  18. Failure Criteria for Reinforced Materials

    DEFF Research Database (Denmark)

    Rathkjen, Arne

    Failure of materials is often characterized as ductile yielding, brittle fracture, creep rupture, etc., and different criteria given in terms of different parameters have been used to describe different types of failure. Only criteria expressing failure in terms of stress are considered in what...... place until the matrix, the continuous component of the composite, fails. When an isotropic matrix is reinforced as described above, the result is an anisotropic composite material. Even if the material is anisotropic, it usually exhibits a rather high degree of symmetry and such symmetries place...... certain restrictions on the form of the failure criteria for anisotropic materials. In section 2, some failure criteria for homogenous materials are reviewed. Both isotropic and anisotropic materials are described, and in particular the constraints imposed on the criteria from the symmetries orthotropy...

  19. Medical therapy for spermatogenic failure

    Institute of Scientific and Technical Information of China (English)

    Ranjith Ramasamy; Peter J Stahl; Peter N Schlegel

    2012-01-01

    Medical treatment of men with primary spermatogenic failure remains largely ineffective in contrast to those with secondary testicular failure.Treatment has been attempted with a multitude of agents ranging from hormones to nutritional supplements (antioxidants).While some studies have demonstrated benefit to some treatments,no treatments have consistently demonstrated efficacy nor has it been possible to reliably identify patients likely to benefit.Idiopathic spermatogenic failure likely results from multiple discrete defects in sperm production that are as yet unidentified.A better understanding of these defects will yield more effective treatment options and appropriate triage of patients to specific therapeutic regimens.This review focuses on the rationale and current evidence for hormonal and antioxidant therapy in medical treatment of male infertility,spermatogenic failure in particular.Although empiric medical therapy for spermatogenic failure has been largely replaced by assisted reproductive techniques,both treatment modalities could play a role,perhaps as combination therapy.

  20. Nuclear cardiology and heart failure

    Energy Technology Data Exchange (ETDEWEB)

    Giubbini, Raffaele; Bertagna, Francesco [University of Brescia, Department of Nuclear Medicine, Brescia (Italy); Milan, Elisa [Ospedale Di Castelfranco Veneto, Nuclear Medicine Unit, Castelfranco Veneto (Italy); Mut, Fernando; Dondi, Maurizio [International Atomic Energy Agency, Nuclear Medicine Section, Division of Human Health, Vienna (Austria); Metra, Marco [University of Brescia, Department of Cardiology, Brescia (Italy); Rodella, Carlo [Health Physics Department, Spedali Civili di Brescia, Brescia (Italy)

    2009-12-15

    The prevalence of heart failure in the adult population is increasing. It varies between 1% and 2%, although it mainly affects elderly people (6-10% of people over the age of 65 years will develop heart failure). The syndrome of heart failure arises as a consequence of an abnormality in cardiac structure, function, rhythm, or conduction. Coronary artery disease is the leading cause of heart failure and it accounts for this disorder in 60-70% of all patients affected. Nuclear techniques provide unique information on left ventricular function and perfusion by gated-single photon emission tomography (SPECT). Myocardial viability can be assessed by both SPECT and PET imaging. Finally, autonomic dysfunction has been shown to increase the risk of death in patients with heart disease and this may be applicable to all patients with cardiac disease regardless of aetiology. MIBG scanning has a very promising prognostic value in patients with heart failure. (orig.)

  1. Bisoprolol for congestive heart failure

    DEFF Research Database (Denmark)

    Rosenberg, J.; Gustafsson, F.

    2008-01-01

    Background: beta-Blockers are a cornerstone in the treatment of systolic heart failure treatment, but not all beta-blockers are effective or in this setting. Objective: To define the role of bisoprolol, a highly selective beta(1)-antagonist in congestive heart failure due to systolic dysfunction....... Methods: Using the keywords 'bisoprolol' and 'heart failure' PubMed and BIOSIS databases were searched for information regarding pharmacology and relevant randomised clinical trials. Supplementary publications were acquired by scrutinising reference lists of relevant papers. Additional information was...... obtained from the FDA website. Conclusion: Bisoprolol is an effective and well-tolerated first-line beta-blocker for patients with systolic heart failure. The knowledge is primarily based on study patients with moderate-to-severe heart failure from the three CIBIS trials Udgivelsesdato: 2008/2...

  2. Nuclear cardiology and heart failure

    International Nuclear Information System (INIS)

    The prevalence of heart failure in the adult population is increasing. It varies between 1% and 2%, although it mainly affects elderly people (6-10% of people over the age of 65 years will develop heart failure). The syndrome of heart failure arises as a consequence of an abnormality in cardiac structure, function, rhythm, or conduction. Coronary artery disease is the leading cause of heart failure and it accounts for this disorder in 60-70% of all patients affected. Nuclear techniques provide unique information on left ventricular function and perfusion by gated-single photon emission tomography (SPECT). Myocardial viability can be assessed by both SPECT and PET imaging. Finally, autonomic dysfunction has been shown to increase the risk of death in patients with heart disease and this may be applicable to all patients with cardiac disease regardless of aetiology. MIBG scanning has a very promising prognostic value in patients with heart failure. (orig.)

  3. Investigation of pellet acceleration by an arc heated gas gun

    International Nuclear Information System (INIS)

    This report describes work on pellet acceleration by means of an arc heated gas gun. The work is a continuation of the work described in RISO-M-2536. The aim of the work is to obtain velocities well above 2 km/s for 3.2 mm diameter deuterium pellets. By means of a cryogenic arc chamber in which the hydrogen propellant is pre-condensed, extruded deutetrium pellets are accelerated up to a maximum velocity of 1.93 km/s. When increasing the energy input to the arc in order to increase the pellet velocity further the heat input to the extrusion/punching pellet loading mechanism was found to be critical: preparation of pellets became difficult and cooling times between shots became inconveniently long. In order to circumvent this problems the concept of a room temperature hydrogen propellant pellet fed arc chamber was proposed. Preliminary results from acceleration of polyurethane pellets with this arc chamber are described as well as the work of developing of feed pellet guns for this chamber. Finally the report describes design consideration for a high pressure propellant pellet fed arc chamber together with preliminary results obtained with a proto-type arc chamber. (author)

  4. The occurrence and damage of unipolar arcing on fuzzy tungsten

    International Nuclear Information System (INIS)

    This research investigated whether unipolar arcing in the divertor of fusion reactors is a potential cause for enhanced wear of the divertor. It was found that 1 μm of nano-fuzz growth is sufficient to initiate arcing, mainly depending on the sheath potential drop and electron density. The average mass loss rate induced by the arc was determined from mass loss measurements and found to be consistent with the value estimated from the arc current. The average arc track erosion depth was estimated by using the measured mass loss and damaged surface area and was found to be one tenth of the fuzzy layer thickness. Due to melting of the fuzzy structures the actual depth is larger and some arc tracks occasionally appeared to even reach the bulk beyond the fuzzy layer. The conclusion of this study is therefore that arcing in the divertor of future tokamaks (e.g. ITER) potentially is an important cause for surface damage and plasma pollution

  5. The occurrence and damage of unipolar arcing on fuzzy tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Aussems, D.U.B., E-mail: d.aussems@differ.nl [FOM Institute DIFFER – Dutch Institute for Fundamental Energy Research, Nieuwegein, NL-3430 BE (Netherlands); Nishijima, D.; Brandt, C. [Center for Energy Research, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0417 (United States); Meiden, H.J. van der [FOM Institute DIFFER – Dutch Institute for Fundamental Energy Research, Nieuwegein, NL-3430 BE (Netherlands); Vilémová, M.; Matějíček, J. [Institute of Plasma Physics, Association EURATOM-IPP, 182 00 Prague 8 (Czech Republic); De Temmerman, G. [FOM Institute DIFFER – Dutch Institute for Fundamental Energy Research, Nieuwegein, NL-3430 BE (Netherlands); Doerner, R.P. [Center for Energy Research, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0417 (United States); Lopes Cardozo, N.J. [Science and Technology of Nuclear Fusion, Eindhoven University of Technology, Den Dolech 2, Eindhoven (Netherlands)

    2015-08-15

    This research investigated whether unipolar arcing in the divertor of fusion reactors is a potential cause for enhanced wear of the divertor. It was found that 1 μm of nano-fuzz growth is sufficient to initiate arcing, mainly depending on the sheath potential drop and electron density. The average mass loss rate induced by the arc was determined from mass loss measurements and found to be consistent with the value estimated from the arc current. The average arc track erosion depth was estimated by using the measured mass loss and damaged surface area and was found to be one tenth of the fuzzy layer thickness. Due to melting of the fuzzy structures the actual depth is larger and some arc tracks occasionally appeared to even reach the bulk beyond the fuzzy layer. The conclusion of this study is therefore that arcing in the divertor of future tokamaks (e.g. ITER) potentially is an important cause for surface damage and plasma pollution.

  6. Lidar arc scan uncertainty reduction through scanning geometry optimization

    Directory of Open Access Journals (Sweden)

    H. Wang

    2015-10-01

    Full Text Available Doppler lidars are frequently operated in a mode referred to as arc scans, wherein the lidar beam scans across a sector with a fixed elevation angle and the resulting measurements are used to derive an estimate of the n minute horizontal mean wind velocity (speed and direction. Previous studies have shown that the uncertainty in the measured wind speed originates from turbulent wind fluctuations and depends on the scan geometry (the arc span and the arc orientation. This paper is designed to provide guidance on optimal scan geometries for two key applications in the wind energy industry: wind turbine power performance analysis and annual energy production. We present a quantitative analysis of the retrieved wind speed uncertainty derived using a theoretical model with the assumption of isotropic and frozen turbulence, and observations from three sites that are onshore with flat terrain, onshore with complex terrain and offshore, respectively. The results from both the theoretical model and observations show that the uncertainty is scaled with the turbulence intensity such that the relative standard error on the 10 min mean wind speed is about 30 % of the turbulence intensity. The uncertainty in both retrieved wind speeds and derived wind energy production estimates can be reduced by aligning lidar beams with the dominant wind direction, increasing the arc span and lowering the number of beams per arc scan. Large arc spans should be used at sites with high turbulence intensity and/or large wind direction variation when arc scans are used for wind resource assessment.

  7. Interruption Phenomenon in Intermediate-Frequency Vacuum Arc

    Science.gov (United States)

    Jiang, Yuan; Wu, Jianwen

    2016-03-01

    In the condition of the 3 mm gap, experiments for 360 Hz intermediate-frequency vacuum arc are carried out in interrupters with the diameters being 41 mm and with the contact materials being CuCr50 and Cu-W-WC alloy respectively. The results indicate that the contacts material is closely related to the breaking capacity of the vacuum interrupters and characteristics of an intermediate-frequency vacuum arc. For contacts with the same diameter, the breaking capacity of CuCr50 is better than that of Cu-W-WC. When the current fails to be interrupted, the arcs overflow the gap and present irregular performances in the first half wave. Consequently a voltage spike appears. More macroscopic metal droplets can be seen in the arc column between CuCr50 contacts because of the lower melting point. It is observed that the droplet emission is much more severe during arc reignition than that in the first half wave. It is much more conspicuous that the high frequency arc voltage noises appear in Cu-W-WC contacts when the vacuum arcs reignite, for higher temperature and stronger electronic emission ability of Cu-W-WC contacts. supported by National Natural Science Foundation of China (No. 51377007), Specialized Research Fund for the Doctoral Program of Higher Education of China (No. 20131102130006), and Fundamental Research Funds for the Central Universities of China

  8. Petrology and tectonics of Phanerozoic continent formation: From island arcs to accretion and continental arc magmatism

    Science.gov (United States)

    Lee, C.-T.A.; Morton, D.M.; Kistler, R.W.; Baird, A.K.

    2007-01-01

    Mesozoic continental arcs in the North American Cordillera were examined here to establish a baseline model for Phanerozoic continent formation. We combine new trace-element data on lower crustal xenoliths from the Mesozoic Sierra Nevada Batholith with an extensive grid-based geochemical map of the Peninsular Ranges Batholith, the southern equivalent of the Sierras. Collectively, these observations give a three-dimensional view of the crust, which permits the petrogenesis and tectonics of Phanerozoic crust formation to be linked in space and time. Subduction of the Farallon plate beneath North America during the Triassic to early Cretaceous was characterized by trench retreat and slab rollback because old and cold oceanic lithosphere was being subducted. This generated an extensional subduction zone, which created fringing island arcs just off the Paleozoic continental margin. However, as the age of the Farallon plate at the time of subduction decreased, the extensional environment waned, allowing the fringing island arc to accrete onto the continental margin. With continued subduction, a continental arc was born and a progressively more compressional environment developed as the age of subducting slab continued to young. Refinement into a felsic crust occurred after accretion, that is, during the continental arc stage, wherein a thickened crustal and lithospheric column permitted a longer differentiation column. New basaltic arc magmas underplate and intrude the accreted terrane, suture, and former continental margin. Interaction of these basaltic magmas with pre-existing crust and lithospheric mantle created garnet pyroxenitic mafic cumulates by fractional crystallization at depth as well as gabbroic and garnet pyroxenitic restites at shallower levels by melting of pre-existing lower crust. The complementary felsic plutons formed by these deep-seated differentiation processes rose into the upper crust, stitching together the accreted terrane, suture and former

  9. Heart failure in North America.

    Science.gov (United States)

    Blair, John E A; Huffman, Mark; Shah, Sanjiv J

    2013-05-01

    Heart failure is a major health problem that affects patients and healthcare systems worldwide. Within the continent of North America, differences in economic development, genetic susceptibility, cultural practices, and trends in risk factors and treatment all contribute to both inter-continental and within-continent differences in heart failure. The United States and Canada represent industrialized countries with similar culture, geography, and advanced economies and infrastructure. During the epidemiologic transition from rural to industrial in countries such as the United States and Canada, nutritional deficiencies and infectious diseases made way for degenerative diseases such as cardiovascular diseases, cancer, overweight/obesity, and diabetes. This in turn has resulted in an increase in heart failure incidence in these countries, especially as overall life expectancy increases. Mexico, on the other hand, has a less developed economy and infrastructure, and has a wide distribution in the level of urbanization as it becomes more industrialized. Mexico is under a period of epidemiologic transition and the etiology and incidence of heart failure is rapidly changing. Ethnic differences within the populations of the United States and Canada highlight the changing demographics of each country as well as potential disparities in heart failure care. Heart failure with preserved ejection fraction makes up approximately half of all hospital admissions throughout North America; however, important differences in demographics and etiology exist between countries. Similarly, acute heart failure etiology, severity, and management differ between countries in North America. The overall economic burden of heart failure continues to be large and growing worldwide, with each country managing this burden differently. Understanding the inter-and within-continental differences may help improve understanding of the heart failure epidemic, and may aid healthcare systems in delivering

  10. Cladding nuclear steels - the application of plasma-arc hot wire surfacing

    International Nuclear Information System (INIS)

    The effect of one and two layer plasma-arc hot wire cladding on the HAZ microstructure of the fine grained structural steel 22 NiMoCr 3 7, which is similar to ASTM A 508, class 2, and steel 20 MnMoNi 5 5, similar to ASTM A 533, grade B, class 1 is determined. Attention is directed particularly to the behaviour of the susceptible region, and the consumables considered are cladding materials X 2 CrNiNb 19 9, similar to ER 347 Elc, and S-NiCr 20 Nb, similar to ER NiCr-3 (Inconel 82). Results of corrosion resistance tests show that this cladding technique can be recommended for manufacture of equipment for the chemical industry to avoid corrosion failure. Plasma-arc hot wire surfacing is also shown to be capable of depositing single or double clad layers to meet the highest safety requirements and could be applied to nuclear power plants for the special manufacture of wear resistant parts and for protection of equipment subject to a variety of corrosive environments. (U.K.)

  11. The influence of hydrogen on the fatigue behaviour of base and gas tungsten arc welded Eurofer

    International Nuclear Information System (INIS)

    Room temperature hydrogen embrittlement susceptibility of Eurofer base-metal and gas-tungsten-arc-welded joint has been investigated by fully-reversed load-control low cycle fatigue. The tests were run on specimens subjected to electrochemical charging before and during cyclic stressing. Compared to the uncharged condition, increasing amounts of hydrogen in base-steel caused fatigue life reduction by promoting premature cracking of either grain boundaries or cleavage planes. Examination of fracture morphologies indicated that the underlying embrittlement mechanisms likely correlated with plastic flow alteration and interatomic bond decohesion, both induced by hydrogen. Specimen-to-specimen response variability by test replication was accounted for in terms of Eurofer material heterogeneity, based on relevant experimental indexes. This interpretation was consistent with the well known sensitivity to microstructure of hydrogen embrittlement processes, and explained the large scatter of fatigue lives and failure modes subsequently observed in equivalently charged Eurofer weld samples

  12. The influence of hydrogen on the fatigue behaviour of base and gas tungsten arc welded Eurofer

    Science.gov (United States)

    Maday, Marie-Françoise; Pilloni, Luciano

    2007-08-01

    Room temperature hydrogen embrittlement susceptibility of Eurofer base-metal and gas-tungsten-arc-welded joint has been investigated by fully-reversed load-control low cycle fatigue. The tests were run on specimens subjected to electrochemical charging before and during cyclic stressing. Compared to the uncharged condition, increasing amounts of hydrogen in base-steel caused fatigue life reduction by promoting premature cracking of either grain boundaries or cleavage planes. Examination of fracture morphologies indicated that the underlying embrittlement mechanisms likely correlated with plastic flow alteration and interatomic bond decohesion, both induced by hydrogen. Specimen-to-specimen response variability by test replication was accounted for in terms of Eurofer material heterogeneity, based on relevant experimental indexes. This interpretation was consistent with the well known sensitivity to microstructure of hydrogen embrittlement processes, and explained the large scatter of fatigue lives and failure modes subsequently observed in equivalently charged Eurofer weld samples.

  13. Wear-resistance and anti-scuffing of multi-arc ion plating molybdenum films

    Institute of Scientific and Technical Information of China (English)

    WANG Hai-dou; XU Bin-shi; LIU Jia-jun; ZHUANG Da-ming

    2004-01-01

    The multi-arc ion plating technology was employed to prepare the molybdenum films with thickness of 3 μm on the AISI 1045 steel. The wear and scuffing tests were carried out on the ball-on-disc tester. AFM and SEM equipped with EDS were adopted to observe and analyze the morphologies and element compositions of surface,cross-section and worn scar of the Mo film. The phase structure was studied by XRD and the bonding strength between Mo film and substrate was measured by scratching tester. The tribological experiments show that the Mo film possesses a good wear-resistance and an excellent anti-scuffing property. The failure mechanism of Mo film under extreme condition is flaking off.

  14. Dependence of Arc Plasma Dispersion Capability on its Temperature

    Institute of Scientific and Technical Information of China (English)

    CHEN Yun-Yun; SONG Yang; HE An-Zhi; LI Zhen-Hua

    2008-01-01

    @@ The relationship between the dispersion capability and the temperature of argon arc plasma at Iatm is deduced in view of the plasma's refractive index equation.The results indicate that argon arc plasma has a normal dispersion and its dispersion capability is nonlinear to the plasma's temperature in a wide range of temperature and wavelength region.According to the results of numerical calculation, the preferred optical methods are believed to be suitable for the diagnosis of argon arc plasma in different temperature regions.

  15. Energy Balance in DC Arc Plasma Melting Furnace

    Institute of Scientific and Technical Information of China (English)

    ZHAO Peng; MENG Yuedong; YU Xinyao; CHEN Longwei; JIANG Yiman; NI Guohua; CHEN Mingzhou

    2009-01-01

    In order to treat hazardous municipal solid waste incinerator's (MSWI) fly ash, a new DC arc plasma furnace was developed. Taking an arc of 100 V/1000 A DC as an example,the heat transfer characteristics of the DC arc plasma, ablation of electrodes, heat properties of the fly ash during melting, heat transfer characteristics of the flue gas, and heat loss of the furnace were analyzed based on the energy conservation law, so as to achieve the total heat information and energy balance during plasma processing, and to provide a theoretical basis for an optimized design of the structure and to improve energy efficiency.

  16. Partial flocks of the quadratic cone yielding Mathon maximal arcs

    CERN Document Server

    De Clerck, Frank; Maes, Thomas

    2011-01-01

    N. Hamilton and J. A. Thas describe a link between maximal arcs of Mathon type and partial flocks of the quadratic cone. This link is of a rather algebraic nature. In this paper we establish a geometric connection between these two structures. We also define a composition on the flock planes and use this to work out an analogue of the synthetic version of Mathon's Theorem. Finally, we show how it is possible to construct a maximal arc of Mathon type of degree 2d, containing a Denniston arc of degree d provided that there is a solution to a certain given system of trace conditions.

  17. Location of silicic caldera formation in arc settings

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Gwyneth R; Mahood, Gail A [Department of Geological and Environmental Sciences, Stanford University, 450 Serra, Mall, Building 320, Stanford, CA 94305-2115 (United States)

    2008-10-01

    Silicic calderas are the surface expressions of silicic magma chambers, and thus their study may yield information about what tectonic and crustal features favor the generation of evolved magma. The goal of this study is to determine whether silicic calderas in arc settings are preferentially located behind the volcanic front. After a global analysis of young, arc-related calderas, we find that silicic calderas at continental margins do form over a wide area behind the front, as compared to other types of arc volcanoes.

  18. INITIATION OF ELECTRIC ARC IN ARGON FLOWING IN WATER CHANNEL

    Czech Academy of Sciences Publication Activity Database

    Chumak, Oleksiy; Hrabovský, Milan; Sforza, T.; Falier, J.

    Brno: Vysoké učení technické v Brně, 2009 - (Aubrecht, V.; Bartlová, M.), s. 138-141 ISBN 978-80-214-3793-7. [Symposium on Physics of Switching Arc/18th./. Nové Město na Moravě (CZ), 07.09.2009-11.09.2009] R&D Projects: GA AV ČR KJB100430701 Institutional research plan: CEZ:AV0Z20430508 Keywords : DC arc torch * breakdown * arc initiation Subject RIV: BL - Plasma and Gas Discharge Physics

  19. Dosimetric verification of RapidArc treatment delivery

    DEFF Research Database (Denmark)

    Korreman, Stine; Medin, Joakim; Kjaer-Kristoffersen, Flemming

    2009-01-01

    PURPOSE: Recently, Varian Medical Systems have announced the introduction of a new treatment technique, in which dose is delivered over a single gantry rotation with variable MLC positions, dose rate and gantry speed. In February 2008, a preclinical installation of the RapidArc beam delivery...... approach was carried out on a Varian Clinac at Rigshospitalet in Copenhagen. The purpose of the installation was to perform measurements to verify the correctness of doses delivered with the RapidArc technique. In May 2008, the clinical release of the RapidArc application was installed at Rigshospitalet...

  20. Synthesis of 2D materials in arc plasmas

    International Nuclear Information System (INIS)

    In this article we review recent efforts focused on synthesis of two-dimensional (2D) materials in an arc-plasma based process with particular focus on graphene. We present state-of-the-art experimental data on various attempts to employ the arc plasma technique for the graphene synthesis and consider growth mechanisms including precipitation, surface-catalyzed processes and a substrate-independent approach. The potential of arc synthesis for the growth of other types of 2D materials and future prospects are discussed. (review article)

  1. mARC: Memory by Association and Reinforcement of Contexts

    OpenAIRE

    Rimoux, Norbert; Descourt, Patrice

    2013-01-01

    This paper introduces the memory by Association and Reinforcement of Contexts (mARC). mARC is a novel data modeling technology rooted in the second quantization formulation of quantum mechanics. It is an all-purpose incremental and unsupervised data storage and retrieval system which can be applied to all types of signal or data, structured or unstructured, textual or not. mARC can be applied to a wide range of information clas-sification and retrieval problems like e-Discovery or contextual ...

  2. Automatic arc discharge technology for inscribing long period fiber gratings.

    Science.gov (United States)

    Yin, Guolu; Tang, Jian; Liao, Changrui; Wang, Yiping

    2016-05-10

    We experimentally demonstrate an automatic arc discharge technology for inscribing high-quality long period fiber gratings (LPFGs) with greatly improved inscription efficiency for single mode fiber (SMF) and photonic crystal fiber (PCF). The proposed technology was developed by implementing an embedded program in a commercial fusion splicer. In addition, the improved technology employs an ultraprecision motorized translation stage, and the tensioning mass required by conventional technology was eliminated. While hundreds of arc discharges are generally required by conventional technology, only 30 and 60 arc discharges were required to inscribe LPFGs with dip attenuations of 30 and 20 dB for SMF and PCF, respectively. PMID:27168306

  3. Heat transfers in a low-pressure arc-jet

    Energy Technology Data Exchange (ETDEWEB)

    Dudeck, M. [Centre National de la Recherche Scientifique (CNRS), 92 - Meudon-Bellevue (France); Kaminska, A. [Politechnika Poznanska, Poznan (Poland)

    1995-03-01

    In the framework of low-pressure arc-jet applications to thermodynamical condition simulation for reentry vehicles at hypersonic speed, an analytical study has been carried out concerning the thermodynamical conditions of a plasma in an arc-source for plasmatron usual operating conditions. After a review of gas physical properties, the gas flow in the plasmatron with a divergent nozzle is modelled; temperature profiles in the arc and in the divergent and the wall heat flux are then computed. Results are given. 8 refs., 6 figs.

  4. Phenomenology of surface arcs on spacecraft dielectric materials

    Science.gov (United States)

    Balmain, K. G.; Gossland, M.; Reeves, R. D.; Kuller, W. G.

    1982-01-01

    For electron beam incidence on large specimens of Kapton thermal blanket material, surface arc discharges are shown to cause damage consisting of punchthrough holes which act as focal points for other types of damage, including subsurface tunnels, blowout holes and surface breakup. Under electron bombardment, dielectric sheet specimens separated by a gap are shown to discharge simultaneously. Teflon specimens which have been brushed or rubbed are shown to exhibit directional guidance of discharge arcs, and this phenomenon has been used to generate straight arcs whose velocities have been measured optically.

  5. Energy Balance in DC Arc Plasma Melting Furnace

    Science.gov (United States)

    Zhao, Peng; Meng, Yuedong; Yu, Xinyao; Chen, Longwei; Jiang, Yiman; Ni, Guohua; Chen, Mingzhou

    2009-04-01

    In order to treat hazardous municipal solid waste incinerator's (MSWI) fly ash, a new DC arc plasma furnace was developed. Taking an arc of 100 V/1000 A DC as an example, the heat transfer characteristics of the DC arc plasma, ablation of electrodes, heat properties of the fly ash during melting, heat transfer characteristics of the flue gas, and heat loss of the furnace were analyzed based on the energy conservation law, so as to achieve the total heat information and energy balance during plasma processing, and to provide a theoretical basis for an optimized design of the structure and to improve energy efficiency.

  6. Feedback between neutral winds and auroral arc electrodynamics

    Science.gov (United States)

    Lyons, L. R.; Walterscheid, R. L.

    1986-01-01

    The feedback between neutral atmospheric winds and the electrodynamics of a stable, discrete auroral arc is analyzed. The ionospheric current continuity equation and the equation for neutral gas acceleration by ion drag are solved simultaneously, as a function of time. The results show that, in general, the electric field in the ionosphere adjusts to neutral wind acceleration so as to keep auroral field-aligned currents and electron acceleration approximately independent of time. It is thus concluded that the neutral winds that develop as a result of the electrodynamical forcing associated with an arc do not significantly affect the intensity of the arc.

  7. Mantle dynamics during arc rupture and back-arc opening: Evidence from Tonga, the Lau Basin and the Lau Islands

    International Nuclear Information System (INIS)

    The geodynamic interplay between a sub-arc mantle with Pacific and/or Indian MORB-like affinities was first described by Hergt and Hawkesworth in 1994. Following this, a number of workers have recognised similar occurrences of these two domains in other arc/back-arc systems of the western Pacific. Controversy exists concerning the origin of these two mantle components and the extent to which they are geographically distributed. In order to test the geodynamic model proposed by Hergt and Hawkesworth (1994) for Tonga and the Lau Basin, additional samples from this region have been studied. These samples, from the Lau Islands, represent a record of magmatism beginning prior to arc rupture (prior to ∼6 Ma) and extending through to 0.3 Ma ago. Lead isotope composition of basalts from the back-arc sites provided additional insights to the study of this region and suggested the involvement of two mantle source region - similar to those producing basalts at the Pacific and Indian mid-ocean ridges. A new model has been proposed describing the tectonic history involved in the opening of the Lau Basin and using this information to re-examine the lead isotope variations, a new pattern emerges; the initial stages of back-arc formation involved horst and graben style extension of the arc crust, and some magmatism occurred within graben structures

  8. New medications for heart failure.

    Science.gov (United States)

    Gordin, Jonathan S; Fonarow, Gregg C

    2016-08-01

    Heart failure is common and results in substantial morbidity and mortality. Current guideline-based therapies for heart failure with reduced ejection fraction, including beta blockers, angiotensin converting enzyme (ACE) inhibitors, and aldosterone antagonists aim to interrupt deleterious neurohormonal pathways and have shown significant success in reducing morbidity and mortality associated with heart failure. Continued efforts to further improve outcomes in patients with heart failure with reduced ejection fraction have led to the first new-in-class medications approved for heart failure since 2005, ivabradine and sacubitril/valsartan. Ivabradine targets the If channels in the sinoatrial node of the heart, decreasing heart rate. Sacubitril/valsartan combines a neprilysin inhibitor that increases levels of beneficial vasodilatory peptides with an angiotensin receptor antagonist. On a background of previously approved, guideline-directed medical therapies for heart failure, these medications have shown improved clinical outcomes ranging from decreased hospitalizations in a select group of patients to a reduction in all-cause mortality across all pre-specified subgroups. In this review, we will discuss the previously established guideline-directed medical therapies for heart failure with reduced ejection fraction, the translational research that led to the development of these new therapies, and the results from the major clinical trials of ivabradine and sacubitril/valsartan. PMID:27038558

  9. Periodontitis in Chronic Heart Failure.

    Science.gov (United States)

    Fröhlich, Hanna; Herrmann, Kristina; Franke, Jennifer; Karimi, Alamara; Täger, Tobias; Cebola, Rita; Katus, Hugo A; Zugck, Christian; Frankenstein, Lutz

    2016-08-01

    Periodontal disease has been associated with an increased risk of cardiovascular events. The purpose of our study was to investigate whether a correlation between periodontitis and chronic heart failure exists, as well as the nature of the underlying cause. We enrolled 71 patients (mean age, 54 ± 13 yr; 56 men) who had stable chronic heart failure; all underwent complete cardiologic and dental evaluations. The periodontal screening index was used to quantify the degree of periodontal disease. We compared the findings to those in the general population with use of data from the 4th German Dental Health Survey. Gingivitis, moderate periodontitis, and severe periodontitis were present in 17 (24%), 17 (24%), and 37 (52%) patients, respectively. Severe periodontitis was more prevalent among chronic heart failure patients than in the general population. In contrast, moderate periodontitis was more prevalent in the general population (P <0.00001). The severity of periodontal disease was not associated with the cause of chronic heart failure or the severity of heart failure symptoms. Six-minute walking distance was the only independent predictor of severe periodontitis. Periodontal disease is highly prevalent in chronic heart failure patients regardless of the cause of heart failure. Prospective trials are warranted to clarify the causal relationship between both diseases. PMID:27547136

  10. Periodontitis in Chronic Heart Failure

    Science.gov (United States)

    Fröhlich, Hanna; Herrmann, Kristina; Franke, Jennifer; Karimi, Alamara; Täger, Tobias; Cebola, Rita; Katus, Hugo A.; Zugck, Christian

    2016-01-01

    Periodontal disease has been associated with an increased risk of cardiovascular events. The purpose of our study was to investigate whether a correlation between periodontitis and chronic heart failure exists, as well as the nature of the underlying cause. We enrolled 71 patients (mean age, 54 ± 13 yr; 56 men) who had stable chronic heart failure; all underwent complete cardiologic and dental evaluations. The periodontal screening index was used to quantify the degree of periodontal disease. We compared the findings to those in the general population with use of data from the 4th German Dental Health Survey. Gingivitis, moderate periodontitis, and severe periodontitis were present in 17 (24%), 17 (24%), and 37 (52%) patients, respectively. Severe periodontitis was more prevalent among chronic heart failure patients than in the general population. In contrast, moderate periodontitis was more prevalent in the general population (P periodontal disease was not associated with the cause of chronic heart failure or the severity of heart failure symptoms. Six-minute walking distance was the only independent predictor of severe periodontitis. Periodontal disease is highly prevalent in chronic heart failure patients regardless of the cause of heart failure. Prospective trials are warranted to clarify the causal relationship between both diseases. PMID:27547136

  11. Understanding failures in petascale computers

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Bianca; Gibson, Garth A [Computer Science Department, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA 15213 (United States)

    2007-07-15

    With petascale computers only a year or two away there is a pressing need to anticipate and compensate for a probable increase in failure and application interruption rates. Researchers, designers and integrators have available to them far too little detailed information on the failures and interruptions that even smaller terascale computers experience. The information that is available suggests that application interruptions will become far more common in the coming decade, and the largest applications may surrender large fractions of the computer's resources to taking checkpoints and restarting from a checkpoint after an interruption. This paper reviews sources of failure information for compute clusters and storage systems, projects failure rates and the corresponding decrease in application effectiveness, and discusses coping strategies such as application-level checkpoint compression and system level process-pairs fault-tolerance for supercomputing. The need for a public repository for detailed failure and interruption records is particularly concerning, as projections from one architectural family of machines to another are widely disputed. To this end, this paper introduces the Computer Failure Data Repository and issues a call for failure history data to publish in it.

  12. Component failure data base of TRIGA reactors

    International Nuclear Information System (INIS)

    This compilation provides failure data such as first criticality, component type description (reactor component, population, cumulative calendar time, cumulative operating time, demands, failure mode, failures, failure rate, failure probability) and specific information on each type of component of TRIGA Mark-II reactors in Austria, Bangladesh, Germany, Finland, Indonesia, Italy, Indonesia, Slovenia and Romania. (nevyjel)

  13. Management of Postoperative Respiratory Failure.

    Science.gov (United States)

    Mulligan, Michael S; Berfield, Kathleen S; Abbaszadeh, Ryan V

    2015-11-01

    Despite best efforts, postoperative complications such as postoperative respiratory failure may occur and prompt recognition of the process and management is required. Postoperative respiratory failure, such as postoperative pneumonia, postpneumonectomy pulmonary edema, acute respiratory distress-like syndromes, and pulmonary embolism, are associated with high morbidity and mortality. The causes of these complications are multifactorial and depend on preoperative, intraoperative, and postoperative factors, some of which are modifiable. The article identifies some of the risk factors, causes, and treatment strategies for successful management of the patient with postoperative respiratory failure. PMID:26515943

  14. Cardiomyocytic apoptosis and heart failure

    Institute of Scientific and Technical Information of China (English)

    Quanzhou Feng

    2008-01-01

    Heart failure is a major disease seriously threatening human health.Once left ventricular dysfunction develops,cardiac function usually deteriorates and progresses to congestive heart failure in several months or years even if no factors which accelerate the deterioration repeatedly exist.Mechanism through which cardiac function continually deteriorates is still unclear.Cardiomyocytic apoptosis can occur in acute stage of ischemic heart diseases and the compensated stage of cardiac dysfunction.In this review,we summarize recent advances in understanding the role of cardiomyocytic apoptosis in heart failure.

  15. Submarine Arc Volcanism in the Southern Mariana Arc: Results of Recent ROV studies

    Science.gov (United States)

    Nichols, A. R.; Tamura, Y.; Stern, R. J.; Embley, R. W.; Hein, J. R.; Jordan, E.; Ribeiro, J. M.; Sica, N.; Kohut, E. J.; Whattam, S. A.; Hirahara, Y.; Senda, R.; Nunokawa, A.

    2009-12-01

    The submarine Diamante cross-arc volcanoes (~16°N) and the Sarigan-Zealandia Bank Multi-Volcano Complex (SZBMVC; ~16°45’N), north and south, respectively, of Anatahan Island in the southern Mariana Arc, were studied during several dives in June 2009 using the ROV Hyper-Dolphin, cruise NT09-08 (R/V Natsushima); neither has been studied in detail before. The data collected provide a new perspective on how the subduction factory operates to complement previous studies on other cross-arc volcanic chains in the Izu-Bonin-Mariana Arc. The Diamante complex consists of three major edifices, two cones (West and Central Diamante) and a more complex caldera-like edifice at the volcanic front (East Diamante). West and Central Diamante are basaltic volcanoes but East Diamante has a more complex history. Our studies indicate initial construction of a basaltic volcano. Magmatic evolution led to a violent caldera-forming and quieter dome-building events. Post-caldera quiescence allowed a carbonate platform to grow, now preserved on the eastern caldera wall. Felsic magma or hot rock provides a heat source for an active hydrothermal field associated with felsic domes in the caldera, which NOAA investigators discovered in 2004. A new type of hydrothermal deposit was discovered in the hydrothermal field, consisting of large sulfide-sulfate mounds topped by bulbous constructions of low-temperature Fe and Mn oxides. Vents on the mounds were observed to emit shimmering water. The SZBMVC consists of six closely spaced edifices whose loci are aligned along two parallel trends, one along the volcanic front (Zealandia Bank, Sarigan and South Sarigan), and one about 15 km west towards the rear-arc (Northwest Zealandia, West Zealandia and West Sarigan). Zealandia Bank dives revealed that, as with East Diamante, initial activity was basaltic and became more evolved with time. The western half of Zealandia Bank is dominated by felsic lavas centered on a small (~2 km diameter) caldera and

  16. 1000-kVA arc power supply

    International Nuclear Information System (INIS)

    Because of ever-increasing power demands for the development of the Oak Ridge duoPIGatron ion source, a continuous-duty arc power supply was constructed for the Medium Energy Test Facility (METF) to furnish power for the plasma generator of experimental ion sources. The power supply utilizes 12-pulse rectification with half-wave switching in a delta and wye full-wave bridge that may be connected in series or parallel. It will deliver 340 V dc, 2500 A to an ion source when series connected and 170 V dc, 5000 A when paralleled connected. Silicon-controlled rectifiers (SCR) in each rectifier bridge can be switched for pulses as short as 10 ms through continuous duty. The filter section that reduces the ripple in the output consists of an inductor-to-capacitor (L-C) filter to smooth the 720-Hz pulses. The power transformer serves as an isolation transformer allowing the secondary to be elevated to the accelerating potential of the ion source. The dc output level is controlled with a 1000-kVA auto transformer connected to the primary of the power transformer. All elevated voltages and currents are monitored at ground potential with an optical telemetry system. This paper describes the power supply in detail, including block diagrams, component specifications, and waveforms when supplying power to an ion source

  17. The ARC-EN-CIEL FEL Proposal

    CERN Document Server

    Couprie, M E

    2005-01-01

    ARC-EN-CIEL (Accelerator-Radiation for Enhanced Coherent Intense Extended Light), the French project of a fourth generation light source aims at providing the user community with coherent femtosecond light pulses covering from UV to soft X ray. It is based on a CW 1 GeV superconducting linear accelerator delivering high charge, subpicosecond, low emittance electron bunches with a high repetition rate. The FEL is based on in the injection of High Harmonics in Gases in a High Gain Harmonic Generation scheme, leading to a rather compact solution. The produced radiation extending down to 0.8 nm with the Non Linear Harmonic reproduces the good longitudinal and transverse coherence of the harmonics in gas. Optional beam loops are foreseen to increase the beam current or the energy. They will accommodate fs synchrotron radiation sources in the IR, VUV and X ray ranges and a FEL oscillator in the 10 nm range. An important synergy is expected between accelerator and laser communities. Indeed, electron plasma accelerat...

  18. Numerical modelling of steel arc welding

    International Nuclear Information System (INIS)

    Welding is a highly used assembly technique. Welding simulation software would give access to residual stresses and information about the weld's microstructure, in order to evaluate the mechanical resistance of a weld. It would also permit to evaluate the process feasibility when complex geometrical components are to be made, and to optimize the welding sequences in order to minimize defects. This work deals with the numerical modelling of arc welding process of steels. After describing the industrial context and the state of art, the models implemented in TransWeld (software developed at CEMEF) are presented. The set of macroscopic equations is followed by a discussion on their numerical implementation. Then, the theory of re-meshing and our adaptive anisotropic re-meshing strategy are explained. Two welding metal addition techniques are investigated and are compared in terms of the joint size and transient temperature and stresses. The accuracy of the finite element model is evaluated based on experimental results and the results of the analytical solution. Comparative analysis between experimental and numerical results allows the assessment of the ability of the numerical code to predict the thermomechanical and metallurgical response of the welded structure. The models limitations and the phenomena identified during this study are finally discussed and permit to define interesting orientations for future developments. (author)

  19. Plasma arc cutting: speed and cut quality

    International Nuclear Information System (INIS)

    When cutting metal with plasma arc cutting, the walls of the cut are narrower at the bottom than at the top. This lack of squareness increases as the cutting speed increases. A model of this phenomenon, affecting cut quality, is suggested. A thin liquid layer, which separates the plasma from the solid metal to be melted, plays a key role in the suggested model. This layer decreases heat transfer from the plasma to the solid metal; the decrease is more pronounced the higher the speed and the thicker the liquid metal layer. Since the layer is thicker at the bottom of the cut, the heat transfer effectiveness is lower at the bottom. The decrease in heat transfer effectiveness is compensated by the narrowness of the cut. The suggested model allows one to calculate the profile of the cut. The result of the calculations of the cutting speeds for plates of various thicknesses, at which the squareness of the cut is acceptable, agrees well with the speeds recommended by manufacturers. The second effect considered in the paper is the deflection of the plasma jet from the vertical at a high cutting speed. A qualitative explanation of this phenomenon is given. We believe the considerations of this paper are pertinent to other types of cutting with moving heat sources.

  20. Magmatic control along a strike-slip volcanic arc: The central Aeolian arc (Italy)

    KAUST Repository

    Ruch, Joel

    2016-01-23

    The regional stress field in volcanic areas may be overprinted by that produced by magmatic activity, promoting volcanism and faulting. In particular, in strike-slip settings, the definition of the relationships between the regional stress field and magmatic activity remains elusive. To better understand these relationships, we collected stratigraphic, volcanic and structural field data along the strike-slip Central Aeolian arc (Italy): here the islands of Lipari and Vulcano separate the extensional portion of the arc (to the east) from the contractional one (to the west). We collected >500 measurements of faults, extension fractures and dikes at 40 sites. Most structures are NNE-SSW to NNW-SSE oriented, eastward dipping, and show almost pure dip-slip motion; consistent with an E-W extension direction, with minor dextral and sinistral shear. Our data highlight six eruptive periods during the last 55 ka, which allow considering both islands as a single magmatic system, in which tectonic and magmatic activity steadily migrated eastward and currently focus on a 10 km long x 2 km wide active segment. Faulting appears to mostly occur in temporal and spatial relation with magmatic events, supporting that most of the observable deformation derives from transient magmatic activity (shorter-term, days to months), rather than from steady longer-term regional tectonics (102-104 years). More in general, the Central Aeolian case shows how magmatic activity may affect the structure and evolution of volcanic arcs, overprinting any strike-slip motion with magma-induced extension at the surface.

  1. Magmatic control along a strike-slip volcanic arc: The central Aeolian arc (Italy)

    Science.gov (United States)

    Ruch, J.; Vezzoli, L.; De Rosa, R.; Di Lorenzo, R.; Acocella, V.

    2016-02-01

    The regional stress field in volcanic areas may be overprinted by that produced by magmatic activity, promoting volcanism and faulting. In particular, in strike-slip settings, the definition of the relationships between the regional stress field and magmatic activity remains elusive. To better understand these relationships, we collected stratigraphic, volcanic, and structural field data along the strike-slip central Aeolian arc (Italy): here the islands of Lipari and Vulcano separate the extensional portion of the arc (to the east) from the contractional one (to the west). We collected >500 measurements of faults, extension fractures, and dikes at 40 sites. Most structures are NNE-SSW to NNW-SSE oriented, eastward dipping, and show almost pure dip-slip motion, consistent with an E-W extension direction, with minor dextral and sinistral shear. Our data highlight six eruptive periods during the last 55 ka, which allow considering both islands as a single magmatic system, in which tectonic and magmatic activities steadily migrated eastward and currently focus on a 10 km long × 2 km wide active segment. Faulting appears to mostly occur in temporal and spatial relation with magmatic events, supporting that most of the observable deformation derives from transient magmatic activity (shorter term, days to months), rather than from steady longer-term regional tectonics (102-104 years). More in general, the central Aeolian case shows how magmatic activity may affect the structure and evolution of volcanic arcs, overprinting any strike-slip motion with magma-induced extension at the surface.

  2. Analysing bifurcations encountered in numerical modelling of current transfer to cathodes of dc glow and arc discharges

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, P G C; Benilov, M S; Cunha, M D; Faria, M J [Departamento de Fisica, Universidade da Madeira, Largo do Municipio, 9000 Funchal (Portugal)

    2009-10-07

    Bifurcations and/or their consequences are frequently encountered in numerical modelling of current transfer to cathodes of gas discharges, also in apparently simple situations, and a failure to recognize and properly analyse a bifurcation may create difficulties in the modelling and hinder the understanding of numerical results and the underlying physics. This work is concerned with analysis of bifurcations that have been encountered in the modelling of steady-state current transfer to cathodes of glow and arc discharges. All basic types of steady-state bifurcations (fold, transcritical, pitchfork) have been identified and analysed. The analysis provides explanations to many results obtained in numerical modelling. In particular, it is shown that dramatic changes in patterns of current transfer to cathodes of both glow and arc discharges, described by numerical modelling, occur through perturbed transcritical bifurcations of first- and second-order contact. The analysis elucidates the reason why the mode of glow discharge associated with the falling section of the current-voltage characteristic in the solution of von Engel and Steenbeck seems not to appear in 2D numerical modelling and the subnormal and normal modes appear instead. A similar effect has been identified in numerical modelling of arc cathodes and explained.

  3. Development of Analysis Program for SF6 Arc Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong C; Ahn, Heui Sub; Choi, Jong Ung; Kim, Young Geun; Oh, Il Sung [Electrotechnology R and D Center, LG Industrial System (Korea)

    2002-07-01

    Because there is a strong interaction between the arc discharge and their surroundings, it is not easy to predict the characteristics of industrial arc plasma systems such as gas circuit breakers. The design procedure of these systems is still largely based on trial and error, although the situation is rapidly improving because of the available computational power at a cost in which is still coming down. The desire to predict the behavior of arc plasma systems, thus optimizing and reducing the development cost, has been the motivation of these arc researches. In this paper, we have simulated the switching operation of a gas circuit breaker during high current area using a computational fluid dynamics considered the electric field analysis, the radiation model and effects of turbulence. (author). 3 refs., 8 figs., 1 tab.

  4. A plasma-arc pyrolysis system for hazardous waste treatment

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ A laboratory system for the treatment of medical and hazardous wastes via AC plasma-arc pyrolysis was recently built up by a research team led by Prof. SHENG Hongzhi at the CAS Institute of Mechanics (IMECH) in Beijing.

  5. Arc Behaviours in Vacuum Interrupters with Axial Magnetic Field Electrodes

    Institute of Scientific and Technical Information of China (English)

    WANG Zhongyi; ZHENG Yuesheng; LIU Zhiyuan; CHENG Shaoyong

    2008-01-01

    To improve the limiting current interruption capability and minimizing vacuum interrupter with axial magnetic field (AMF) electrodes,it is significant to investigate the vacuum arc behaviours between the contacts.AMF distributions of the slot type electrodes were studied by both numerical analysis and experiments. Furthermore,the behaviours of vacuum arcs for different parameters of the slot type AMF electrodes were investigated by using high-speed CCD camera.The influences of gap distance,contact diameter and phase shift time between AMF and arc current on the vacuum arc were investigated.The results provide a reference for research and development of vacuum interrupters with slot type or other types of AMF electrode.

  6. Cyclic erosion of a cathode in high-pressure arcs

    Energy Technology Data Exchange (ETDEWEB)

    Nemchinsky, Valerian [ESAB Welding and Cutting Products and Francis Marion University, Florence, SC 29501 (United States)

    2003-07-07

    Erosion that occurred during arc shut down was investigated. The arc current was 200 A; the cathode was made of hafnium. Different gases were used: oxygen, nitrogen, and noble gases (argon, helium, and hydrogen-argon mixture). The gas pressure was 3 atm. It was shown that erosion in noble gases is higher compared to gases that create chemical compounds with hafnium (oxygen and nitrogen). The following model of arc-off erosion is suggested. An amount of plasma gas is diluted in the molten tip of the cathode. When the arc is terminated, the gas pressure in the cathode vicinity drops down. The diluted gas then leaves the molten puddle and carries some liquid material with it.

  7. Simple filtered repetitively pulsed vacuum arc plasma source

    International Nuclear Information System (INIS)

    A very simple design of cathodic filtered vacuum arc plasma source is proposed. The source without filter has only four components and none of them require precise machining. The source operates in a repetitively pulsed regime, and for laboratory experiments it can be used without water cooling. Despite the simple construction, the source provides high ion current at the filter outlet reaching 2.5% of 400 A arc current, revealing stable operation in a wide pressure range from high vacuum to oxygen pressure up to more than 10-2 mbar. There is no need in complicated power supply system for this plasma source, only one power supply can be used to ignite the arc, to provide the current for the arc itself, to generate the magnetic field in the filter, and provide its positive electric biasing without any additional high power resistance.

  8. Destruction of PCDD/Fs by gliding arc discharges

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    PCDD/Fs have been become a serious issue because of their lexicological effects and associated adverse health implications. In this study, the gliding arc plasma was tested for treatment of polychlorinated dibenzo-p-dioxins (PCDDs) and pol ychlorinated dibenzofurans (PCDFs), which was synthesized from pentachlorophenol in atmospheric condition at 350℃ with or without the catalysis of CuCh-From the experiment, we found that the destruction efficiency of PCDD/F homologues after gliding was discharge ranged from 25% to 79%. This result demonstrates that gliding arc plasma is an effective technology to decompose PCDDs/Fs in flue gas. A plausible degradation mechanism for PCDD/Fs by gliding arc was discussed. Finally, a multistage reactor structure of gliding arc was proposed to upgrade removal efficiency for PCDD/Fs.

  9. British Columbia 3 arc-second Bathymetric Digital Elevation Model

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 3 arc-second British Columbia DEM will be used to support NOAA's tsunami forecast system and for tsunami inundation modeling. This DEM covers the coastal area...

  10. The effect of arc velocity on cold electrode erosion

    International Nuclear Information System (INIS)

    Results of experimental investigations of copper cathode erosion in a magnetically driven arc versus arc rotation velocity v are presented. The erosion rate measurements were carried out with the arc burning in air, for magnetic induction values B in the range of 0.005-0.386 T, axial air gas velocity of 7.65 ms-1, and current of 292 A. It is shown that in the range of small values of v and B, the mass erosion rate diminishes with v and B. Then, the erosion remains constant for a certain range of v and B, and, subsequently, begins to grow. This information is very important for the correct use of magnetic fields to decrease erosion in arc heaters

  11. High Alumina Refractory Bricks for Electric Arc Furnace Roofs

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ 1 Scope This standard specifies the sort, technical requirement, test method, inspection rules, marking, packing, transportation, storage and quality certification of high alumina refractory bricks for electric arc furnace roofs.

  12. Arc-Discharge Ion Sources for Heavy Ion Fusion

    International Nuclear Information System (INIS)

    A miniature multiple beamlet approach to an injector system was recently proposed in order to reduce the size, cost, and power requirements of the injector. The beamlets of very high current density are needed to meet the brightness requirement. Besides vacuum arc ion sources, cold-cathode gas ion sources are candidates for this application. Vacuum-arc metal ion sources and vacuum-arc-like gas ion sources are discussed. Experiments are presented that focus on the short-pulse plasma composition and ion charge state distribution. Mg and Sr have been identified as the most promising metals leading to mono-species beams when 20 μs arc pulses are used. It is shown that the efficient production of gas ions requires the presence of a magnetic field

  13. Improvement of electrical arc furnace operation with an appropriate model

    International Nuclear Information System (INIS)

    Electrical arc furnaces are commonly employed in industry to produce molten steel by melting iron and scrap steel. Furnace control is a necessary operation for production optimization. The principal parameters to be controlled are: maximum productivity requirements, minimum power off time, good power quality and safety. The aim of this study is to achieve all these objectives. Hence, because of the stochastic and dynamic behaviour of the arc during the melting process, a proposed model is checked with measurements at an industrial electrical arc furnace. How electrodes position and transformer taps can affect X and R arc function are discussed in detail. This new operating strategy has been determined taking into account Flicker, melting stages and electrode positions. It is shown that optimum efficiency can be reached by the integration of the proposed model in regulation loop.

  14. Theory of the free full-circle arc

    International Nuclear Information System (INIS)

    A theoretical investigation of the full-cirle arc located between two planes is presented. The circular arc shape is due to an applied magnetic field. The basic equations for conservations of mass, momentum, energy, and charge, as well as Maxwell's equations and the equation of state lead to a coupled set of partial differential equations. By means of Green's formula, this set is transformed into a set of integral equations. Using the analytically known Green's function, the system may be solved by an iteration procedure. For a simplified arc model, the quantities of interest are computed: The temperature distribution, the mass flow field, and the external magnetic field necessary to maintain this arc configuration. (orig.)

  15. A study on consumable aided tungsten indirect arc welding

    Institute of Scientific and Technical Information of China (English)

    Wang Jun; Wang Yuxin; Feng Jicai

    2009-01-01

    A consumable aided tungsten indirect arc welding method has been studied. This method is different from the traditional TIG welding because it introduces an MIG welding torch into the traditional TIG welding system. An indirect arc is generated between the consumable electrode of the MIG welding torch and the tungsten electrode of the TIG welding torch, but not generated between the tungsten electrode of the welding torch and the base metal. Welding current flows from the consumable electrode to the tungsten electrode in the free-burning indirect arc. The consumable aided tungsten indirect arc welding not only rapidly melts the welding wire but also effectively restrains the excessive fusion of the base metal. The welding experiment and the theoretical analysis confirm that this method can obtain a high deposition rate and a low dilution ratio during the welding process.

  16. Method for defect free keyhole plasma arc welding

    Science.gov (United States)

    Harwig, Dennis D. (Inventor); Hunt, James F. (Inventor); Ryan, Patrick M. (Inventor); Fisher, Walter J. (Inventor)

    1993-01-01

    A plasma arc welding process for welding metal of increased thickness with one pass includes operating the plasma arc welding apparatus at a selected plasma gas flow rate, travel speed and arc current, to form a weld having a penetration ratio to weld height to weld width, and maintaining the penetration ratio at less than 0.74. Parameters for the plasma gas flow rate, travel speed and arc current are adjusted to a steady state condition during a start up period and maintained during the steady state condition to complete a weld. During a terminal stopping period, the travel speed is stopped and instantaneously replaced by filler wire which adds material to fill the keyhole that had been formed by the welding process. Parameters are subsequently adjusted during the stopping period to terminate the weld in a sound manner.

  17. ArcHydro global datasets for Hawaii StreamStats

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset consists of a personal geodatabase containing several vector datasets. These datasets may be used with the ArcHydro Tools, developed by ESRI in...

  18. Bermuda 1 arc-second Coastal Digital Elevation Model

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 1 arc-second Bermuda DEM will be used to support NOAA's tsunami forecast system and for tsunami inundation modeling. This DEM encompasses the islands of Bermuda...

  19. Bermuda 3 arc-second Coastal Digital Elevation Model

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 3 arc-second Bermuda DEM will be used to support NOAA's tsunami forecast system and for tsunami inundation modeling. This DEM encompasses the islands of Bermuda...

  20. TRAP230/ARC240 and TRAP240/ARC250 Mediator subunits are functionally conserved through evolution

    DEFF Research Database (Denmark)

    Samuelsen, Camilla O; Baraznenok, Vera; Khorosjutina, Olga;

    2003-01-01

    In Saccharomyces cerevisiae Mediator, a subgroup of proteins (Srb8, Srb9, Srb10, and Srb11) form a module, which is involved in negative regulation of transcription. Homologues of Srb10 and Srb11 are found in some mammalian Mediator preparations, whereas no clear homologues have been reported for...... Srb8 and Srb9. Here, we identify a TRAP240/ARC250 homologue in Schizosaccharomyces pombe and demonstrate that this protein, spTrap240, is stably associated with a larger form of Mediator, which also contains conserved homologues of Srb8, Srb10, and Srb11. We find that spTrap240 and Sch. pombe Srb8 (sp...

  1. Rapid Arc for heat and Neck cancer (200 patients experience)

    Energy Technology Data Exchange (ETDEWEB)

    Fandino, J. M.; Triana, G.; Gesto, C.; Diaz, I.; Candal, A.; Fernandez, C.; Izquierdo, P.; Poncet, M.; Silva, M. C.; Soto, M.; Losada, C.; Marino, A.

    2013-07-01

    Intensity Modulated Radiotherapy is increasingly standard for head and neck cancer. These advances have resulted in longer treatment times when compared to 3D Conformal Radiotherapy. Volumetric Modulated Arc Therapy potentially enables shorter treatment time, achieving similar dose results. We report feasibility and acute toxicity profile of patients treated with moderate hypo fractionation and simultaneous integrated boost by means of Image Guided- Volumetric Modulated Arc Therapy technique in the first two years from its clinical implementation at COG. (Author)

  2. Regulation of p53 tetramerization and nuclear export by ARC

    OpenAIRE

    Foo, Roger S.-Y.; Nam, Young-Jae; Ostreicher, Marc Jason; Metzl, Mark D.; Whelan, Russell S.; Peng, Chang-Fu; Ashton, Anthony W.; Fu, Weimin; Mani, Kartik; Chin, Suet-Feung; Provenzano, Elena; Ellis, Ian; Figg, Nichola; Pinder, Sarah; Bennett, Martin R.

    2007-01-01

    Inactivation of the transcription factor p53 is central to carcinogenesis. Yet only approximately one-half of cancers have p53 loss-of-function mutations. Here, we demonstrate a mechanism for p53 inactivation by apoptosis repressor with caspase recruitment domain (ARC), a protein induced in multiple cancer cells. The direct binding in the nucleus of ARC to the p53 tetramerization domain inhibits p53 tetramerization. This exposes a nuclear export signal in p53, triggering Crm1-dependent reloca...

  3. An observation of ionospheric convection and auroral arc motion

    International Nuclear Information System (INIS)

    An all-sky imager operated at Sondre Stromfjord, Greenland has been used to make auroral measurements in correlation with data from the incoherent scatter radar. Reviewing the images as movie sequences with an apparent time compression ratio of 60 allows the eye to discern features which are not apparent in the individual frames. The faint 630 nm airglow background lying poleward of the bright auroral oval arcs appears to be structured in the time lapse observations and drifting at a uniform rate. Analysis of the motion of the airglow structures shows excellent agreement with Doppler radar measurement of the ion drift velocities. Electron density profiles derived from the radar data corroborate the existence of high altitude F-region ionization enhancements. The electron temperature in the patches was about 1,000 K and no higher than outside of the patch signifying that the patches were not produced by local soft electron precipitation. According to the radar Doppler data there was a small component of the drift velocity parallel to the arc at either side of the auroral boundary. The sense of those small components was consistent with drifts driven by a convergent electric field which would also produce an up going field aligned current. The larger component of drift velocity perpendicular to the arc appeared to be continuous on either side of the arc. This drift component shows the existence of an electric field parallel to the arc, showing that the arc was not on an equipotential. During the observations the arc moved slowly in the opposite sense to the ion drift, signifying that the auroral arc motion is not driven by the electric field impressed on the atmosphere by the magnetosphere. Calculations of the expected intensity of the 630 nm emissions are in good agreement with the measured intensities of the moving patches

  4. On the nonlinear design of industrial arc spring dampers

    DEFF Research Database (Denmark)

    Lahriri, Said; Santos, Ilmar; Hartmann, Henning

    2011-01-01

    for varying the damping characteristics of the SFD as well as the dynamic forces acting on the SFD. Phase plane orbits together with Poincar´e maps are given for different arc spring damping and static and dynamic load cases. Besides, bifurcation diagrams as a function of the arc spring damping and...... forces acting on the SFD are presented. It is worth mentioning, that the maps and diagrams can be used as design guidance....

  5. Barrier island arcs along abandoned Mississippi River deltas

    Science.gov (United States)

    Penland, S.; Suter, J.R.; Boyd, Ron

    1985-01-01

    Generation of transgressive barrier island arcs along the Mississippi River delta plain and preservation of barrier shoreline facies in their retreat paths on the inner shelf is controlled by: (1) shoreface translation; (2) age of the transgression; and (3) the thickness of the barrier island arc sediment package. Barrier island arcs experience an average relative sea level rise of 0.50-1.00 cm yr-1 and shoreface retreat rates range from 5-15 m yr-1. Young barrier island arc sediment packages (Isles Dernieres) are thin and have experienced limited landward retreat of the shoreface. Older barrier island arcs (Chandeleur Islands) are thicker and have experienced significant landward movement of the shoreface because of the greater time available for retreat. If the transgressed barrier shoreline sediment package lies above the advancing ravinement surface, the entire sequence is truncated. A thin reworked sand sheet marks the shoreface retreat path. The base of the transgressive sediment package can lie below the ravinement surface in older barrier shorelines. In this setting, the superstructure of the barrier shoreline is truncated, leaving the basal portion of the transgressive sequence preserved on the inner shelf. A variety of transgressive stratigraphic sequences from sand sheets to truncated barrier islands to sand-filled tidal inlet scars have been identified by high resolution seismic profiling across the shoreface retreat paths of Mississippi delta barrier island arcs. One of these examples, the Isles Dernieres, represents a recently detached barrier island arc in the early stages of transgression. An older example, the Chandeleur Islands, represents a barrier island arc experiencing long-term shoreface retreat. This paper describes the stratigraphic character and preserved transgressive facies for the Isles Dernieres and Chandeleur Islands. ?? 1985.

  6. Anatomy and neuro-pathophysiology of the cough reflex arc

    OpenAIRE

    Polverino Mario; Polverino Francesca; Fasolino Marco; Andò Filippo; Alfieri Antonio; De Blasio Francesco

    2012-01-01

    Abstract Coughing is an important defensive reflex that occurs through the stimulation of a complex reflex arc. It accounts for a significant number of consultations both at the level of general practitioner and of respiratory specialists. In this review we first analyze the cough reflex under normal conditions; then we analyze the anatomy and the neuro-pathophysiology of the cough reflex arc. The aim of this review is to provide the anatomic and pathophysiologic elements of evaluation of the...

  7. First d. c. arc furnace for steelmaking in the world

    Energy Technology Data Exchange (ETDEWEB)

    1982-09-06

    On June 25, 1982, a prototype d.c. arc furnace with a capacity of 12 t started trial operation at the Kreuztal-Buschhuetten steel foundry of Messrs. SMS Schloemann-Siemag AG, after its operating capability had been tested with same test charges. It is the world's first d.c. arc furnace to be operated in a production plant. The furnaces constructed so far were experimental furnaces, operated periodically for research purposes.

  8. Evaporative behavior of carbon with MPD Arc Jet

    Energy Technology Data Exchange (ETDEWEB)

    Sukegawa, Toshio; Madarame, Haruki; Okamoto, Koji [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab.

    1996-10-01

    Using the Magneto-Plasma-Dynamic Arc Jet (MPD Arc Jet) device, the plasma-material interaction during simulated plasma disruption was experimentally investigated. To clarify the effects of the evaporation, the isotropic graphite was used as a target. The thermal conductivity of the isotropic graphite was much higher than that of the pyrolytic graphite, resulting in smaller evaporation. The light intensity distribution during the simulated disruption for the isotropic graphite was quite different from that for the pyrolytic graphite. (author)

  9. Clinical utility of RapidArcTM radiotherapy technology

    Directory of Open Access Journals (Sweden)

    Infusino E

    2015-11-01

    Full Text Available Erminia Infusino Department of Radiotherapy, Campus Bio-Medico University Hospital, Rome, Italy Abstract: RapidArcTM is a radiation technique that delivers highly conformal dose distributions through the complete rotation (360° and speed variation of the linear accelerator gantry. This technique, called volumetric modulated arc therapy (VMAT, compared with conventional radiotherapy techniques, can achieve high-target volume coverage and sparing damage to normal tissues. RapidArc delivers precise dose distribution and conformity similar to or greater than intensity-modulated radiation therapy in a short time, generally a few minutes, to which image-guided radiation therapy is added. RapidArc has become a currently used technology in many centers, which use RapidArc technology to treat a large number of patients. Large and small hospitals use it to treat the most challenging cases, but more and more frequently for the most common cancers. The clinical use of RapidArc and VMAT technology is constantly growing. At present, a limited number of clinical data are published, mostly concerning planning and feasibility studies. Clinical outcome data are increasing for a few tumor sites, even if only a little. The purpose of this work is to discuss the current status of VMAT techniques in clinical use through a review of the published data of planning systems and clinical outcomes in several tumor sites. The study consisted of a systematic review based on analysis of manuscripts retrieved from the PubMed, BioMed Central, and Scopus databases by searching for the keywords "RapidArc", "Volumetric modulated arc radiotherapy", and "Intensity-modulated radiotherapy". Keywords: IMRT, VMAT, SBRT, SRS, treatment planning software 

  10. Friedel oscillations due to Fermi arcs in Weyl semimetals

    OpenAIRE

    Hosur, Pavan

    2012-01-01

    Weyl semimetals harbor unusual surface states known as Fermi arcs, which are essentially disjoint segments of a two dimensional Fermi surface. We describe a prescription for obtaining Fermi arcs of arbitrary shape and connectivity by stacking alternate two dimensional electron and hole Fermi surfaces and adding suitable interlayer coupling. Using this prescription, we compute the local density of states -- a quantity directly relevant to scanning tunneling microscopy -- on a Weyl semimetal su...

  11. Theoretical-experimental investigation of intensively blasted electric arc

    Czech Academy of Sciences Publication Activity Database

    Hrabovský, Milan; Heinz, J.; Jakubová, I.; Šenk, J.

    Toulous, 2004 - (Bordage, M.; Gleizes, A.; Gonzales, J.), s. 129-132 [International Conference on Gas Discharges and their Applications - GD 2004 /15./. Toulouse (FR), 05.09.2004-10.09.2004] R&D Projects: GA AV ČR IAA1057202 Institutional research plan: CEZ:AV0Z2043910 Keywords : electric arc, plasma generator, arc heater, thermal plasma Subject RIV: BL - Plasma and Gas Discharge Physics

  12. Research on Resonance Mechanism of Arc-ultrasonic

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@As a transmission medium, welding arc can be modulated to emit ultrasonic energy by exerting high-frequency electric current. The frequency of exciting electric current has notable influence on the signals recorded by the sensors and the metallographic structures of the welds. The resonance phenomenon of arc-ultrasonic has been found in the experiment. Both the resonance mechanism and the distribution of resonance frequency are discussed by the built vibration equation.

  13. Role of substrate temperature at graphene synthesis in arc discharge

    CERN Document Server

    Fang, Xiuqi; Keidar, Michael

    2015-01-01

    Substrate temperature required for synthesis of graphene in arc discharge plasma was studied. It was shown that increase of the copper substrate temperature up to melting point leads to increase in the amount of graphene production and quality of graphene sheets. Favorable range of substrate temperatures for arc-based graphene synthesis was determined in relatively narrow range of about 1340-1360K which is near the melting point of copper.

  14. Gas Contamination In Plasma-Arc-Welded Aluminum

    Science.gov (United States)

    Mcclure, John C.; Torres, Martin R.; Gurevitch, Alan C.; Newman, Robert A.

    1992-01-01

    Document describes experimental investigation on visible and tactile effects of gaseous contaminants in variable-polarity plasma arc (VPPA) welding of 2219 T-87 aluminum alloy. Contaminant gases (nitrogen, methane, oxygen, and hydrogen) introduced in argon arc and in helium shield gas in various controlled concentrations. Report represents results of experiments in form of photographs of fronts, backs, polished cross sections, and etched cross sections of welds made with various contaminants at various concentrations. Provides detailed discussion of conditions under which welds made.

  15. A review of vacuum ARC ion source research at ANSTO

    Energy Technology Data Exchange (ETDEWEB)

    Evans, P.J.; Noorman, J.T.; Watt, G.C. [ANSTO, Menai (Australia)

    1996-08-01

    The authors talk briefly describes the history and current status of vacuum arc ion source research at the Australian Nuclear Science and Technology Organization (ANSTO). In addition, the author makes some mention of the important role of previous Vacuum Arc Ion Source Workshops in fostering the development of this research field internationally. During the period 1986 - 89, a type of plasma centrifuge known as a vacuum arc centrifuge was developed at ANSTO as part of a research project on stable isotope separation. In this device, a high current vacuum arc discharge was used to produce a metal plasma which was subsequently rotated in an axial magnetic field. The high rotational speeds (10{sup 5} - 10{sup 6} rad sec{sup {minus}1}) achievable with this method produce centrifugal separation of ions with different mass:charge ratios such as isotopic species. The first portent of things to come occurred in 1985 when Dr. Ian Brown visited ANSTO`s Lucas Heights Research Laboratories and presented a talk on the metal vapour vacuum arc (MEVVA) ion source which had only recently been invented by Brown and co-workers, J. Galvin and R. MacGill, at Lawrence Berkeley Laboratory. For those of us involved in vacuum arc centrifuge research, this was an exciting development primarily because the metal vapour vacuum arc plasma source was common to both devices. Thus, a type of arc, which had since the 1930`s been extensively investigated as a means of switching high current loads, had found wider application as a useful plasma source.

  16. Intestinal Failure (Short Bowel Syndrome)

    Science.gov (United States)

    ... the area where the intestine was reconnected N Kidney stones or gallstones due to poor absorption of calcium or bile How is intestinal failure treated? The diet needs to be adjusted according to the intestine’s ...

  17. Lifestyle Changes for Heart Failure

    Science.gov (United States)

    ... Pressure High Blood Pressure Tools & Resources Stroke More Lifestyle Changes for Heart Failure Updated:May 4,2016 ... so it becomes a regular part of your lifestyle. Managing stress Take 15 to 20 minutes a ...

  18. Ejection Fraction Heart Failure Measurement

    Science.gov (United States)

    ... Tools & Resources Stroke More Ejection Fraction Heart Failure Measurement Updated:May 31,2016 The ejection fraction (EF) is an important measurement in determining how well your heart is pumping ...

  19. Planning Ahead: Advanced Heart Failure

    Science.gov (United States)

    ... Pressure High Blood Pressure Tools & Resources Stroke More Planning Ahead: Advanced Heart Failure Updated:Jul 7,2016 ... making your preferences known is called advance care planning. It allows you to speak for yourself, even ...

  20. Managing Feelings about Heart Failure

    Science.gov (United States)

    ... time. Although people with heart failure commonly experience depression or anxiety, that does not mean you have to accept ... them to get better on their own. Recognizing Depression and Anxiety Everyone feels anxious or blue some of the ...

  1. Polyhydramnios and acute renal failure

    OpenAIRE

    Hamilton, D. V.; Kelly, Moira B.; Pryor, J. S.

    1980-01-01

    Acute renal failure secondary to ureteric obstruction is described in a primigravida with twin gestation and polyhydramnios. Relief of the obstruction occurred on drainage of the liquor and return to normal renal function following delivery.

  2. How Is Respiratory Failure Treated?

    Science.gov (United States)

    ... Once your doctor figures out what's causing your respiratory failure, he or she will plan how to treat that disease or condition. Treatments may include medicines, procedures, and other therapies. Rate This Content: NEXT >> Updated: December 19, 2011 Twitter ...

  3. Predicting Failures in Power Grids

    CERN Document Server

    Chertkov, Michael; Stepanov, Mikhail G

    2010-01-01

    Here we develop an approach to predict power grid weak points, and specifically to efficiently identify the most probable failure modes in load distribution for a given power network. This approach is applied to two examples: Guam's power system and also the IEEE RTS-96 system, both modeled within the static Direct Current power flow model. Our algorithm is a power network adaption of the worst configuration heuristics, originally developed to study low probability events in physics and failures in error-correction. One finding is that, if the normal operational mode of the grid is sufficiently healthy, the failure modes, also called instantons, are sufficiently sparse, i.e. the failures are caused by load fluctuations at only a few buses. The technique is useful for discovering weak links which are saturated at the instantons. It can also identify overutilized and underutilized generators, thus providing predictive capability for improving the reliability of any power network.

  4. Measurements of the total ion flux from vacuum arc cathodespots

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Andre; Oks, Efim M.; Yushkov, Georgy Yu; Savkin,Konstantin P.; Brown, Ian G.; Nikolaev, Alexey G.

    2005-05-25

    The ion flux from vacuum arc cathode spots was measured in two vacuum arc systems. The first was a vacuum arc ion source which was modified allowing us to collect ions from arc plasma streaming through an anode mesh. The second discharge system essentially consisted of a cathode placed near the center of a spherically shaped mesh anode. In both systems, the ion current streaming through the mesh was measured by a biased collector. The mesh anodes had geometric transmittances of 60 percent and 72 percent, respectively, which were taken into account as correction factors. The ion current from different cathode materials was measured for 50-500 A of arc current. The ion current normalized by the arc current was found to depend on the cathode material, with values in the range from 5 percent to 19 percent. The normalized ion current is generally greater for elements of low cohesive energy. The ion erosion rates were determined from values of ion current and ion charge states, which were previously measured in the same ion source. The absolute ion erosion rates range from 16-173 mu g/C.

  5. The global relevance of the Scotia Arc: An introduction

    Science.gov (United States)

    Maldonado, Andrés; Dalziel, Ian W. D.; Leat, Philip T.

    2015-02-01

    The Scotia Arc, situated between South America and Antarctica, is one of the Earth's most important ocean gateways and former land bridges. Understanding its structure and development is critical for the knowledge of tectonic, paleoenvironmental and biological processes in the southern oceans and Antarctica. It extends from the Drake Passage in the west, where the Shackleton Fracture Zone forms a prominent, but discontinuous, bathymetric ridge between the southern South American continent and the northern tip of the Antarctic Peninsula to the active intra-oceanic volcanic arc forming the South Sandwich Island in the east. The tectonic arc comprises the NSR to the north and to the south the South Scotia Ridge, both transcurrent plate margins that respectively include the South Georgia and South Orkney microcontinents. The Scotia and Sandwich tectonic plates form the major basin within these margins. As the basins opened, formation of first shallow sea ways and then deep ocean connections controlled the initiation and development of the Antarctic Circumpolar Current, which is widely thought to have been important in providing the climatic conditions for formation of the polar ice-sheets. The evolution of the Scotia Arc is therefore of global palaeoclimatic significance. The Scotia Arc has been the focus of increasing international research interest. Many recent studies have stressed the links and interactions between the solid Earth, oceanographic, paleoenvironmental and biological processes in the area. This special issue presents new works that summarize significant recent research results and synthesize the current state of knowledge for the Scotia Arc.

  6. Investigation of Optimal Control System for Arc Spraying

    Institute of Scientific and Technical Information of China (English)

    LIHe-qi; LIChun-xu; CHENKe-xuan; LUGuang

    2004-01-01

    An arc voltage feedback PID controller and arc current feedback PID controller are designed with a controlal gorithm of discrete PID separately to realize optimal control in computer controlling arc-spraying system. In order to realize optimization and adaptation of the arc-spraying process parameters as well as to reduce blindness in selecting process parameters, a serial communication interface between a PC for spraying data acquisition and a MCU of the control system is designed so that on-line modification of the PID control parameters is implemented. At the same time, a genetic algorithm is adopted to optimize the control parameters of PID controller, where the difference between the actually sampled value and the setting value of spraying current is made as the judgment criterion to determine the adaptability. The given range of control parameters varies from 0 to 15 and is to be encoded by a coding of four-bit binary string. The optimal population of control parameters of the PID controller can be obtained through reproduction, crossing and mutation, so that the optimal controlling in arc-spraying process is realized and an excellent coating of arc spraying is obtained.

  7. Optimal partial-arcs in VMAT treatment planning

    CERN Document Server

    Wala, Jeremiah; Chen, Wei; Craft, David

    2012-01-01

    Purpose: To improve the delivery efficiency of VMAT by extending the recently published VMAT treatment planning algorithm vmerge to automatically generate optimal partial-arc plans. Methods and materials: A high-quality initial plan is created by solving a convex multicriteria optimization problem using 180 equi-spaced beams. This initial plan is used to form a set of dose constraints, and a set of partial-arc plans is created by searching the space of all possible partial-arc plans that satisfy these constraints. For each partial-arc, an iterative fluence map merging and sequencing algorithm (vmerge) is used to improve the delivery efficiency. Merging continues as long as the dose quality is maintained above a user-defined threshold. The final plan is selected as the partial arc with the lowest treatment time. The complete algorithm is called pmerge. Results: Partial-arc plans are created using pmerge for a lung, liver and prostate case, with final treatment times of 127, 245 and 147 seconds. Treatment times...

  8. Finite symmetric graphs with two-arc transitive quotients III

    CERN Document Server

    Xu, Guangjun

    2012-01-01

    A graph $\\Ga$ is $G$-symmetric if $\\Ga$ admits $G$ as a group of automorphisms acting transitively on the set of vertices and the set of arcs of $\\Ga$, where an arc is an ordered pair of adjacent vertices. In the case when $G$ is imprimitive on $V(\\Ga)$, namely when $V(\\Ga)$ admits a nontrivial $G$-invariant partition $\\BB$, the quotient graph $\\Ga_{\\BB}$ of $\\Ga$ with respect to $\\BB$ is always $G$-symmetric and sometimes even $(G, 2)$-arc transitive. (A $G$-symmetric graph is $(G, 2)$-arc transitive if $G$ is transitive on the set of oriented paths of length two.) In this paper we obtain necessary conditions for $\\Ga_{\\BB}$ to be $(G, 2)$-arc transitive (regardless of whether $\\Ga$ is $(G, 2)$-arc transitive) in the case when $v-k$ is an odd prime $p$, where $v$ is the block size of $\\BB$ and $k$ is the number of vertices in a block having neighbours in a fixed adjacent block. These conditions are given in terms of $v, k$ and two other parameters with respect to $(\\Ga, \\BB)$ together with a certain 2-point ...

  9. Arc damage of interelectrode insulators in MHD generators

    International Nuclear Information System (INIS)

    The damage to interelectrode insulators on the anode wall of an MHD generator, resulting from magnetically driven arcs, has been studied experimentally and analytically. Recession rates of about 1-3 mm/s and damage widths of about 2-4 mm were measured for alumina, boron-nitride, and magnesia insulators at arc currents ranging from 7 to 83 A and at magnetic fields up to 1 T. The recession rate and damage width were affected by both the magnetic body force (IB) and the power dissipated in the arc. In general, boron-nitride performed best and alumina worst. A simple model of the steady arc and the heat transfer from the insulator predicted the damage parameters within a factor of 2. Damage from unsteady arcing can also occur and has not been addressed in detail. The relationship of the fault arc voltage-current characteristics to the width and spacing of electrode sections required for an MHD generator is presented

  10. Lidar arc scan uncertainty reduction through scanning geometry optimization

    Science.gov (United States)

    Wang, Hui; Barthelmie, Rebecca J.; Pryor, Sara C.; Brown, Gareth.

    2016-04-01

    Doppler lidars are frequently operated in a mode referred to as arc scans, wherein the lidar beam scans across a sector with a fixed elevation angle and the resulting measurements are used to derive an estimate of the n minute horizontal mean wind velocity (speed and direction). Previous studies have shown that the uncertainty in the measured wind speed originates from turbulent wind fluctuations and depends on the scan geometry (the arc span and the arc orientation). This paper is designed to provide guidance on optimal scan geometries for two key applications in the wind energy industry: wind turbine power performance analysis and annual energy production prediction. We present a quantitative analysis of the retrieved wind speed uncertainty derived using a theoretical model with the assumption of isotropic and frozen turbulence, and observations from three sites that are onshore with flat terrain, onshore with complex terrain and offshore, respectively. The results from both the theoretical model and observations show that the uncertainty is scaled with the turbulence intensity such that the relative standard error on the 10 min mean wind speed is about 30 % of the turbulence intensity. The uncertainty in both retrieved wind speeds and derived wind energy production estimates can be reduced by aligning lidar beams with the dominant wind direction, increasing the arc span and lowering the number of beams per arc scan. Large arc spans should be used at sites with high turbulence intensity and/or large wind direction variation.

  11. Financial Failures and Risk Management

    OpenAIRE

    Yener, Coskun

    2012-01-01

    Financial failures observed during global financial crisis have again underlined the importance of effective risk management. In this article, the author analyzes the best instrument, namely self discipline, official discipline and market discipline, for the effective risk management. In the light of literature review and lessons of firm/system wide financial failures, we also analyze degree of efficieny of disciplinary methods. We first conclude, however it may not provide optimal s...

  12. Heart Failure in North America

    OpenAIRE

    Blair, John E.A.; Huffman, Mark; Shah, Sanjiv J.

    2013-01-01

    Heart failure is a major health problem that affects patients and healthcare systems worldwide. Within the continent of North America, differences in economic development, genetic susceptibility, cultural practices, and trends in risk factors and treatment all contribute to both inter-continental and within-continent differences in heart failure. The United States and Canada represent industrialized countries with similar culture, geography, and advanced economies and infrastructure. During t...

  13. Respiratory failure in diabetic ketoacidosis

    OpenAIRE

    Konstantinov, Nikifor K; Rohrscheib, Mark; Agaba, Emmanuel I.; Dorin, Richard I.; Murata, Glen H.; Tzamaloukas, Antonios H.

    2015-01-01

    Respiratory failure complicating the course of diabetic ketoacidosis (DKA) is a source of increased morbidity and mortality. Detection of respiratory failure in DKA requires focused clinical monitoring, careful interpretation of arterial blood gases, and investigation for conditions that can affect adversely the respiration. Conditions that compromise respiratory function caused by DKA can be detected at presentation but are usually more prevalent during treatment. These conditions include de...

  14. Algorithms to identify failure pattern

    OpenAIRE

    Poudel, Bhuwan Krishna Som

    2013-01-01

    This project report was written for ?Algorithms to Identify Failure Pattern? at NTNU (Norwegian University of Science and Technology), IME (Faculty of Information Technology, Mathematics and Electrical Engineering) and IDI (Department of Computer Science).In software application, there are three types of failure pattern: point pattern, block pattern and stripe pattern. The purpose of the report is to prepare an algorithm that identifies the pattern in a software application. Only theoretical ...

  15. Tachycardia-Induced Heart Failure

    OpenAIRE

    Patel, Jitenbhai J; Whittaker, Charles T

    2007-01-01

    Heart failure associated with tachyarrhythmias can very often be reversed by dealing with the underlying tachyarrhythmia. Typically characterized by left ventricular dilation and subsequent systolic dysfunction, this disorder can be caused by both atrial and ventricular arrhythmias, most commonly chronic atrial fibrillation. Whereas for most cardiomyopathies there is little that can be done to reverse the progression of the disease, in tachycardia-induced heart failure the patient's often deb...

  16. Anemia, Growth Failure and Hypothyroidism

    OpenAIRE

    Chaytors, Richard Gordon; Higgins, Gerald

    1980-01-01

    A 12-year-old Caucasian female presented to her family physician with an old complaint of anemia and a new complaint of failure to grow. The anemia, first observed four years previously, had been diagnosed as iron deficiency, but had never satisfactorily responded to adequate iron therapy. Investigation of the failure to grow resulted in a diagnosis of hypothyroidism with related normochromic normocytic anemia.

  17. Edge effects and delamination failures

    Science.gov (United States)

    Herakovich, C. T.

    1989-01-01

    The fundamental relationship between the morphology of a composite laminate and the resulting free edge effects is explored and related to delamination failures. Cross-ply, angle-ply, and quasi-isotropic laminates are discussed in detail. It is shown that the local mismatch in elastic properties of adjacent layers and the global stacking sequence of a laminate both have a significant influence on the interlaminar stresses and delamination failures.

  18. Structure of propagating arc in a magneto-hydrodynamic rail plasma actuator

    Science.gov (United States)

    Gray, Miles D.; Choi, Young-Joon; Sirohi, Jayant; Raja, Laxminarayan L.

    2016-01-01

    The spatio-temporal evolution of a magnetically driven arc in a rail plasma flow actuator has been characterized with high-speed imaging, electrical measurements, and spectroscopy. The arc draws a peak current of ~1 kA. High-speed framing cameras were used to observe the complex arc propagation phenomenon. In particular, the anode and cathode roots were observed to have different modes of transit, which resulted in distinct types of electrode degradation on the anode and cathode surfaces. Observations of the arc electrical properties and induced magnetic fields are used to explain the transit mechanism of the arc. Emission spectroscopy revealed the arc temperature and species composition as a function of transit distance of the arc. The results obtained offer significant insights into the electromagnetic properties of the arc-rail system as well as arc-surface interaction phenomena in a propagating arc.

  19. [Metabolic therapy for heart failure].

    Science.gov (United States)

    Loiacono, Ferdinando; Alberti, Luca; Lauretta, Ludovica; Puccetti, Patrizia; Silipigni, Carmen; Margonato, Alberto; Fragasso, Gabriele

    2014-01-01

    Heart failure may promote metabolic changes such as insulin resistance, in part through neurohumoral activation, and determining an increased utilization of non-carbohydrate substrates for energy production. In fact, fasting blood ketone bodies as well as fat oxidation have been shown to be increased in patients with heart failure. The result is depletion of myocardial ATP, phosphocreatine and creatine kinase with decreased efficiency of mechanical work. A direct approach to manipulate cardiac energy metabolism consists in modifying substrate utilization by the failing heart. To date, the most effective metabolic treatments include several pharmacological agents that directly inhibit fatty acid oxidation. The results of current research are supporting the concept that shifting the energy substrate preference away from fatty acid metabolism and toward glucose metabolism could be an effective adjunctive treatment in patients with heart failure. Trimetazidine is the most studied drug in this context. Several small studies have evidenced the usefulness of such additional therapeutic tools for heart failure. More specifically, recent meta-analyses and a multicenter retrospective study have shown that additional use of trimetazidine in patients with heart failure, along with symptoms and cardiac function improvement, also provides a significant protective effect on all-cause mortality, cardiovascular events and hospitalization due to cardiac causes. Nevertheless, the exact role of metabolic therapy in heart failure is yet to be established, and a large multicenter randomized trial is necessary. PMID:25072544

  20. [Critical care for organ failure].

    Science.gov (United States)

    Shiga, H; Hirasawa, H

    1998-08-01

    We retrospectively studied the critical care regimen for multiple organ failure (MOF) in 141 surgical MOF patients treated in the intensive care unit of Chiba University Hospital between January 1988 and April 1998. Patients with gut failure received parenteral instead of enteral nutrition for various reasons such as concomitant ileus. Of the patients with respiratory failure. 138 were placed on a ventilator and 6 received percutaneous cardiopulmonary support. Continuous hemodiafiltration (CHDF) was performed in 98 patients with renal failure. Plasma exchange was carried out in 13 patients with liver failure. Of these patients, 62 (44%) survived. Colloid osmotic pressure was used as an indicator for fluid therapy. For prophylaxis against bacterial translocation, we performed selective digestive decontamination. Recently blood purification methods, particularly CHDF, have become common in the critical care setting. CHDF is efficacious not only as continuous renal replacement therapy but also as a humoral mediator modulator and is currently the first-choice method for blood purification in critical care. In conclusion, there have been many advances in the critical care of patients with organ failure. Multidisciplinary treatment, including artificial support for failing organs, is necessary for the survival of these patients. PMID:9789289

  1. [Competence Network Heart Failure (CNHF). Together against heart failure].

    Science.gov (United States)

    Ertl, Georg; Störk, Stefan; Börste, Rita

    2016-04-01

    Heart failure is one of the most urgent medical and socio-economic challenges of the 21(st) century. Up to three million people are affected in Germany; this means one in ten people over the age of 65  live with heart failure. The current demographic changes will accentuate the importance of this grave health problem. The care of patients with heart failure, as well as the associated research mandates a comprehensive, multidisciplinary approach. The Competence Network Heart Failure (CNHF) pursues this objective. CNHF is a research alliance with 11 sites in Germany and was funded by the Federal Ministry of Research (BMBF) from 2003 through 2014. Since January 2015, the network has been an associate cooperating partner of the German Centre for Cardiovascular Research (DZHK). During the 12-year funding period by the BMBF, scientists in the field of heart failure from 30 university hospitals, 5 research institutes, 7 heart centers, 17 cardiovascular clinics, over 200 general practitioners, 4 rehabilitation clinics, as well as numerous organizations and associations were involved in cooperative CNHF research. In the context of 22 projects, the CNHF covered basic, clinical, and health care research, and generated numerous groundbreaking insights into disease mechanisms, as well as diagnosis and treatment of heart failure, which are documented in more than 350 publications. With its central study database and bank of biomaterials, the network has set up a Europe-wide unique research resource, which can be used in the future for national and international cooperations with the DZHK and other partners. Furthermore, the CNHF strongly promotes nation- and Europe-wide public relations and heart failure awareness activities. PMID:26979718

  2. Simultaneous MV-kV imaging for intrafractional motion management during volumetric-modulated arc therapy delivery.

    Science.gov (United States)

    Hunt, Margie A; Sonnick, Mark; Pham, Hai; Regmi, Rajesh; Xiong, Jian-Ping; Morf, Daniel; Mageras, Gig S; Zelefsky, Michael; Zhang, Pengpeng

    2016-01-01

    The purpose of this study was to evaluate the accuracy and clinical feasibility of a motion monitoring method employing simultaneously acquired MV and kV images during volumetric-modulated arc therapy (VMAT). Short-arc digital tomosynthesis (SA-DTS) is used to improve the quality of the MV images that are then combined with orthogonally acquired kV images to assess 3D motion. An anthropomorphic phantom with implanted gold seeds was used to assess accuracy of the method under static, typical prostatic, and respiratory motion scenarios. Automatic registra-tion of kV images and single MV frames or MV SA-DTS reconstructed with arc lengths from 2° to 7° with the appropriate reference fiducial template images was performed using special purpose-built software. Clinical feasibility was evaluated by retrospectively analyzing images acquired over four or five sessions for each of three patients undergoing hypofractionated prostate radiotherapy. The standard deviation of the registration error in phantom using MV SA-DTS was similar to single MV images for the static and prostate motion scenarios (σ = 0.25 mm). Under respiratory motion conditions, the standard deviation of the registration error increased to 0.7mm and 1.7 mm for single MV and MV SA-DTS, respectively. Registration failures were observed with the respiratory scenario only and were due to motion-induced fiducial blurring. For the three patients studied, the mean and standard deviation of the difference between automatic registration using 4° MV SA-DTS and manual registration using single MV images results was 0.07±0.52mm. The MV SA-DTS results in patients were, on average, superior to single-frame MV by nearly 1 mm - significantly more than what was observed in phantom. The best MV SA-DTS results were observed with arc lengths of 3° to 4°. Registration failures in patients using MV SA-DTS were primarily due to blockage of the gold seeds by the MLC. The failure rate varied from 2% to 16%. Combined MV SA

  3. Simultaneous MV-kV imaging for intrafractional motion management during volumetric-modulated arc therapy delivery*

    Science.gov (United States)

    Hunt, Margie A.; Sonnick, Mark; Pham, Hai; Regmi, Rajesh; Xiong, Jian-ping; Morf, Daniel; Mageras, Gig S.; Zelefsky, Michael; Zhang, Pengpeng

    2016-01-01

    The purpose of this study was to evaluate the accuracy and clinical feasibility of a motion monitoring method employing simultaneously acquired MV and kV images during volumetric-modulated arc therapy (VMAT). Short-arc digital tomosynthesis (SA-DTS) is used to improve the quality of the MV images that are then combined with orthogonally acquired kV images to assess 3D motion. An anthropomorphic phantom with implanted gold seeds was used to assess accuracy of the method under static, typical prostatic, and respiratory motion scenarios. Automatic registration of kV images and single MV frames or MV SA-DTS reconstructed with arc lengths from 2° to 7° with the appropriate reference fiducial template images was performed using special purpose-built software. Clinical feasibility was evaluated by retrospectively analyzing images acquired over four or five sessions for each of three patients undergoing hypofractionated prostate radiotherapy. The standard deviation of the registration error in phantom using MV SA-DTS was similar to single MV images for the static and prostate motion scenarios (σ = 0.25 mm). Under respiratory motion conditions, the standard deviation of the registration error increased to 0.7mm and 1.7 mm for single MV and MV SA-DTS, respectively. Registration failures were observed with the respiratory scenario only and were due to motion-induced fiducial blurring. For the three patients studied, the mean and standard deviation of the difference between automatic registration using 4° MV SA-DTS and manual registration using single MV images results was 0.07±0.52mm. The MV SA-DTS results in patients were, on average, superior to single-frame MV by nearly 1 mm — significantly more than what was observed in phantom. The best MV SA-DTS results were observed with arc lengths of 3° to 4°. Registration failures in patients using MV SA-DTS were primarily due to blockage of the gold seeds by the MLC. The failure rate varied from 2% to 16%. Combined MV SA

  4. The occurence of Heavy Metals and Metalloids in Surficial Lake Sediments before and after a Tailings Dam Failure.

    OpenAIRE

    VRHOVNIK, PETRA; DOLENEC, TADEJ; Serafimovski, Todor; Dolenec, Matej; Rogan Šmuc, Nastja

    2013-01-01

    Tailings dam failures arc relatively rare but can cause extremely high and long-term impacts on the environment. The Sasa tailings dam collapsed in August 2003 and caused an intensive flow of tailings material through the Kamenica River all the way to Lake Kalimanci, where most of the tailings material discharged. This study deals with the characterization of surficial lake sediments from Lake Kalimanci in eastern Macedonia. Mineralogical, geochemical, and statistical analyses of surficial se...

  5. Reinvestigation of the charge density distribution in arc discharge fusion system

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Lin Horng; Yee, Lee Kim; Nan, Phua Yeong; Thung, Yong Yun; Khok, Yong Thian; Rahman, Faidz Abd [Centre of Photonics and Advance Material, Universiti Tunku Abdul Rahman Kuala Lumpur (Malaysia)

    2015-04-24

    A continual arc discharge system has been setup and the light intensity of arc discharge has been profiled. The mathematical model of local energy density distribution in arc discharge fusion has been simulated which is in good qualitative agreement with light intensity profile of arc discharge in the experiments. Eventually, the local energy density distribution of arc discharge system is able to be precisely manipulated to act as heat source in the fabrication of fused fiber devices.

  6. Architecture and Behavior Modeling of Cyber-Physical Systems with MontiArcAutomaton

    OpenAIRE

    Ringert, Jan Oliver; Rumpe, Bernhard; Wortmann, Andreas

    2015-01-01

    This book presents MontiArcAutomaton, a modeling language for architecture and be- havior modeling of Cyber-Physical Systems as interactive Component & Connector mod- els. MontiArcAutomaton extends the Architecture Description Language MontiArc with automata to describe component behavior. The modeling language MontiArcAutomaton provides syntactical elements for defin- ing automata with states, variables, and transitions inside MontiArc components. These syntactical elements and a basic set o...

  7. Posouzení vlivu funkce Stream Definition ArcGIS nadstavby Arc Hydro Tools na charakteristiky povodí

    OpenAIRE

    Tomáš, Tomáš

    2014-01-01

    In my bachelor's thesis working with Geographic information system (GIS) application for creation and calculations of hydrological characteristics of catchment area. Part of the thesis is also brief information on how to calculate hydrological characteristics of catchment area of Dírenský stream. Next part of the work presents a brief description of program ArcGIS and its extension Arc Hydro, followed by characterization of used functions and components in above mentioned programs. The ...

  8. Cardiac Exposure in the Dynamic Conformal Arc Therapy, Intensity-Modulated Radiotherapy and Volumetric Modulated Arc Therapy of Lung Cancer

    OpenAIRE

    Xin Ming; Yuanming Feng; Huan Liu; Ying Zhang; Li Zhou; Jun Deng

    2015-01-01

    Purpose To retrospectively evaluate the cardiac exposure in three cohorts of lung cancer patients treated with dynamic conformal arc therapy (DCAT), intensity-modulated radiotherapy (IMRT), or volumetric modulated arc therapy (VMAT) at our institution in the past seven years. Methods and Materials A total of 140 lung cancer patients were included in this institutional review board approved study: 25 treated with DCAT, 70 with IMRT and 45 with VMAT. All plans were generated in a same commercia...

  9. Calculation of pressure rise in electrical installations due to internal arcs considering SF 6-air mixtures and arc energy absorbers

    OpenAIRE

    Anantavanich, Kittipong

    2010-01-01

    Internal arcs cause sudden temperature and thus pressure increase in electrical installations, which may endanger personnel, installation rooms or buildings as well as the security of power supply. Overpressure can be controlled by e.g. relief openings. The proof of internal arc withstand is usually performed by tests in high power laboratories or by pressure calculations especially in cases, where tests are impractical. Nowadays, there exist reliable pressure calculation methods, which are a...

  10. Common Cause Failures and Ultra Reliability

    Science.gov (United States)

    Jones, Harry W.

    2012-01-01

    A common cause failure occurs when several failures have the same origin. Common cause failures are either common event failures, where the cause is a single external event, or common mode failures, where two systems fail in the same way for the same reason. Common mode failures can occur at different times because of a design defect or a repeated external event. Common event failures reduce the reliability of on-line redundant systems but not of systems using off-line spare parts. Common mode failures reduce the dependability of systems using off-line spare parts and on-line redundancy.

  11. Modulation indices for volumetric modulated arc therapy

    International Nuclear Information System (INIS)

    The aim of this study is to present a modulation index (MI) for volumetric modulated arc therapy (VMAT) based on the speed and acceleration analysis of modulating-parameters such as multi-leaf collimator (MLC) movements, gantry rotation and dose-rate, comprehensively. The performance of the presented MI (MIt) was evaluated with correlation analyses to the pre-treatment quality assurance (QA) results, differences in modulating-parameters between VMAT plans versus dynamic log files, and differences in dose-volumetric parameters between VMAT plans versus reconstructed plans using dynamic log files. For comparison, the same correlation analyses were performed for the previously suggested modulation complexity score (MCSv), leaf travel modulation complexity score (LTMCS) and MI by Li and Xing (MI Li and Xing). In the two-tailed unpaired parameter condition, p values were acquired. The Spearman’s rho (rs) values of MIt, MCSv, LTMCS and MI Li and Xing to the local gamma passing rate with 2%/2 mm criterion were −0.658 (p < 0.001), 0.186 (p = 0.251), 0.312 (p = 0.05) and −0.455 (p = 0.003), respectively. The values of rs to the modulating-parameter (MLC positions) differences were 0.917, −0.635, −0.857 and 0.795, respectively (p < 0.001). For dose-volumetric parameters, MIt showed higher statistically significant correlations than the conventional MIs. The MIt showed good performance for the evaluation of the modulation-degree of VMAT plans. (paper)

  12. Risk of radiogenic second cancers following volumetric modulated arc therapy and proton arc therapy for prostate cancer

    Science.gov (United States)

    Rechner, Laura A.; Howell, Rebecca M.; Zhang, Rui; Etzel, Carol; Lee, Andrew K.; Newhauser, Wayne D.

    2012-11-01

    Prostate cancer patients who undergo radiotherapy are at an increased risk to develop a radiogenic second cancer. Proton therapy has been shown to reduce the predicted risk of second cancer when compared to intensity modulated radiotherapy. However, it is unknown if this is also true for the rotational therapies proton arc therapy and volumetric modulated arc therapy (VMAT). The objective of this study was to compare the predicted risk of cancer following proton arc therapy and VMAT for prostate cancer. Proton arc therapy and VMAT plans were created for three patients. Various risk models were combined with the dosimetric data (therapeutic and stray dose) to predict the excess relative risk (ERR) of cancer in the bladder and rectum. Ratios of ERR values (RRR) from proton arc therapy and VMAT were calculated. RRR values ranged from 0.74 to 0.99, and all RRR values were shown to be statistically less than 1, except for the value calculated with the linear-non-threshold risk model. We conclude that the predicted risk of cancer in the bladder or rectum following proton arc therapy for prostate cancer is either less than or approximately equal to the risk following VMAT, depending on which risk model is applied.

  13. ArcGIS Framework for Scientific Data Analysis and Serving

    Science.gov (United States)

    Xu, H.; Ju, W.; Zhang, J.

    2015-12-01

    ArcGIS is a platform for managing, visualizing, analyzing, and serving geospatial data. Scientific data as part of the geospatial data features multiple dimensions (X, Y, time, and depth) and large volume. Multidimensional mosaic dataset (MDMD), a newly enhanced data model in ArcGIS, models the multidimensional gridded data (e.g. raster or image) as a hypercube and enables ArcGIS's capabilities to handle the large volume and near-real time scientific data. Built on top of geodatabase, the MDMD stores the dimension values and the variables (2D arrays) in a geodatabase table which allows accessing a slice or slices of the hypercube through a simple query and supports animating changes along time or vertical dimension using ArcGIS desktop or web clients. Through raster types, MDMD can manage not only netCDF, GRIB, and HDF formats but also many other formats or satellite data. It is scalable and can handle large data volume. The parallel geo-processing engine makes the data ingestion fast and easily. Raster function, definition of a raster processing algorithm, is a very important component in ArcGIS platform for on-demand raster processing and analysis. The scientific data analytics is achieved through the MDMD and raster function templates which perform on-demand scientific computation with variables ingested in the MDMD. For example, aggregating monthly average from daily data; computing total rainfall of a year; calculating heat index for forecasting data, and identifying fishing habitat zones etc. Addtionally, MDMD with the associated raster function templates can be served through ArcGIS server as image services which provide a framework for on-demand server side computation and analysis, and the published services can be accessed by multiple clients such as ArcMap, ArcGIS Online, JavaScript, REST, WCS, and WMS. This presentation will focus on the MDMD model and raster processing templates. In addtion, MODIS land cover, NDFD weather service, and HYCOM ocean model

  14. Stress corrosion cracking behaviour of gas tungsten arc welded super austenitic stainless steel joints

    Directory of Open Access Journals (Sweden)

    M. Vinoth Kumar

    2015-09-01

    Full Text Available Super 304H austenitic stainless steel with 3% of copper posses excellent creep strength and corrosion resistance, which is mainly used in heat exchanger tubing of the boiler. Heat exchangers are used in nuclear power plants and marine vehicles which are intended to operate in chloride rich offshore environment. Chloride stress corrosion cracking is the most likely life limiting failure with austenitic stainless steel tubing. Welding may worsen the stress corrosion cracking susceptibility of the material. Stress corrosion cracking susceptibility of Super 304H parent metal and gas tungsten arc (GTA welded joints were studied by constant load tests in 45% boiling MgCl2 solution. Stress corrosion cracking resistance of Super 304H stainless steel was deteriorated by GTA welding due to the formation of susceptible microstructure in the HAZ of the weld joint and the residual stresses. The mechanism of cracking was found to be anodic path cracking, with transgranular nature of crack propagation. Linear relationships were derived to predict the time to failure by extrapolating the rate of steady state elongation.

  15. Electrode voltage fall and total voltage of a transient arc

    Science.gov (United States)

    Valensi, F.; Ratovoson, L.; Razafinimanana, M.; Masquère, M.; Freton, P.; Gleizes, A.

    2016-06-01

    This paper deals with an experimental study of the components of a transient arc total voltage with duration of a few tens of ms and a current peak close to 1000 A. The cathode tip is made of graphite whereas the flat anode is made either of copper or of graphite; the electrodes gap is a few mm. The analysis of the electrical parameters is supported and validated by fast imaging and by two models: the first one is a 2D physical model of the arc allowing to calculate both the plasma temperature field and the arc voltage; the second model is able to estimate the transient heating of the graphite electrode. The main aim of the study was to detect the possible change of the cathode voltage fall (CVF) during the first instants of the arc. Indeed it is expected that during the first ms the graphite cathode is rather cool and the main mechanism of the electron emission should be the field effect emission, whereas after several tens of ms the cathode is strongly heated and thermionic emission should be predominant. We have observed some change in the apparent CVF but we have shown that this apparent change can be attributed to the variation of the solid cathode resistance. On the other hand, the possible change of CVF corresponding to the transition between a ‘cold’ and a ‘hot’ cathode should be weak and could not be characterized considering our measurement uncertainty of about 2 V. The arc column voltage (ACV) was estimated by subtracting the electrode voltage fall from the total arc voltage. The experimental transient evolution of the ACV is in very good agreement with the theoretical variation predicted by the model, showing the good ability of the model to study this kind of transient arc.

  16. Electrical and hydrodynamic characterization of a high current pulsed arc

    Science.gov (United States)

    Sousa Martins, R.; Chemartin, L.; Zaepffel, C.; Lalande, Ph; Soufiani, A.

    2016-05-01

    High current pulsed arcs are of significant industrial interest and, aiming to reduce time and cost, there is progressively more and more need for computation tools that describe and predict the behaviour of these arcs. These simulation codes need inputs and validations by experimental databases, but accurate data is missing for this category of electric discharges. The principal lack of understanding is with respect to the transient phase of the current, which can reach thousands of amperes in a few microseconds. In this paper, we present the work realized on an experimental setup that simulates in the laboratory an arc column subjected to five levels of high pulsed current, ranging from 10 kA to 100 kA, with the last one corresponding to the standard lightning current waveform used in aircraft certification processes. This device was instrumented by high speed video cameras to assess the characteristic sizes of the arc channel and to characterize the shock wave generated by the arc expansion. The arc channel radius was measured over time during the axisymmetric phase and reached 3.2 cm. The position and velocity of the shock wave was determined during the first 140 μs. The background-oriented schlieren method was used to study the shock wave and a model for the light deflection inside the shock wave was developed. The mass density profile of the shock wave was estimated and showed good agreement with Rankine–Hugoniot relations at the wave front. Electrical measurements were also used to estimate the time-dependent resistance and conductivity of the arc for times lasting up to 50 μs.

  17. Properties of surface arc discharge in a supersonic airflow

    International Nuclear Information System (INIS)

    An experimental study of a direct-current, surface arc discharge in a Mach 2 cold supersonic airflow is presented. The surface arc discharge is generated with cylindrical tungsten electrodes flush-mounted on a boron-nitride ceramic plate embedded in the lower wall of the supersonic test section. In the presence of airflow, gas breakdown voltage increases from 1.5 kV in stationary air to 2 kV due to particle number density augmentation in the flow. The surface arc discharge transforms from a continuous mode in stationary air to a pulsed-repetitive mode in the flow. The mean time interval between discharge pulses is about 4.3 ms. For a single pulse, arc discharge occupies only about 60 μs. The discharge photos taken by a high-speed CCD camera (framing rate 1125 Hz) validate this pulsed-repetitive process and indicate that the plasma channel of the surface arc discharge is blown downstream by the supersonic flow. As the length of the plasma channel increases, the discharge voltage also increases. When the channel length reaches a critical value (∼25 mm), the dc power supply (3 kV-4 kW) cannot sustain the discharge voltage (∼3 kV) and the Joule heating energy cannot balance the dissipation of constrained convection, and hence the discharge quenches immediately. Current and voltage measurements demonstrate that the discharge process in a single pulse can be separated into three distinct phases: strong-pulsed breakdown process, steady discharge process and discharge attenuation process. Finally, the underlying mechanism of the dynamic process of surface arc discharge in supersonic flow is discussed. This paper provides more insights into the mechanism of supersonic flow control (in particular, shock waves) by a surface arc discharge.

  18. The ingredients of supervisor failure.

    Science.gov (United States)

    Ladany, Nicholas

    2014-11-01

    Trainees all too often learn more about how not to conduct supervision than how to conduct supervision effectively. The purpose of this article is to present a conceptualization of the theoretical, empirical, and practical elements of supervisor failures. Specifically, the article attends to the following behaviors that may lead to supervisor failure: (a) denigrate the supervisory relationship; (b) demonstrate multicultural incompetence; (c) become an unethical supermodel; (d) use evaluation instruments that could not pass for an undergraduate thesis; (e) teach your trainee how to diagnose narcissism by example; (f) apply psychotherapy models in supervision as if there is a theoretical or empirical basis; (g) infantalize your trainee; (h) collude with your trainee; (i) make your trainee your surrogate psychotherapist; and (j) go on a date with your trainee. Recommendations for increasing supervisor success and limiting supervisor failure are provided. PMID:25220894

  19. Submersion and acute respiratory failure

    Institute of Scientific and Technical Information of China (English)

    Yu-Jang Su

    2014-01-01

    Objectives:To know the relationship between hypothermia, etiology, respiratory failure and prognosis of submersion in environmental emergency medicine.Methods:FromDecember1, 2002 toSeptember30,2007, there were52 hospitalized near- drowning cases in a medical center at northernTaiwan.Retrospective study of52 submersion patients who were hospitalized during the duration was analyzed.Results:The hypothermic groups are more commonly seen in acute respiratory failure after submersion,36%vs.21%,P<0.05.The hypothermic submersion patients who are older in age than normothermic submersion patients(44vs.27 years old,P<0.05).The suicidal submersion patients are older, hypothermic and longer length of stay than accidental submersion patients.Conclusions:Submersion patients who are hypothermic on arrival of emergency department(ED) are risky to respiratory failure and older, more hypothermic, longer hospital stay in suicidal submersion patients.

  20. Respiratory failure in diabetic ketoacidosis

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Respiratory failure complicating the course of diabeticketoacidosis (DKA) is a source of increased morbidityand mortality. Detection of respiratory failure in DKA requiresfocused clinical monitoring, careful interpretationof arterial blood gases, and investigation for conditionsthat can affect adversely the respiration. Conditions thatcompromise respiratory function caused by DKA can bedetected at presentation but are usually more prevalentduring treatment. These conditions include deficits ofpotassium, magnesium and phosphate and hydrostatic ornon-hydrostatic pulmonary edema. Conditions not causedby DKA that can worsen respiratory function under theadded stress of DKA include infections of the respiratorysystem, pre-existing respiratory or neuromuscular diseaseand miscellaneous other conditions. Prompt recognitionand management of the conditions that can lead torespiratory failure in DKA may prevent respiratory failureand improve mortality from DKA.