Extremal dependencies and rank correlations in power law networks

NARCIS (Netherlands)

Volkovich, Y.; Litvak, Nelli; Zwart, B.; Jie, Z.

2009-01-01

We analyze dependencies in complex networks characterized by power laws (Web sample, Wikipedia sample and a preferential attachment graph) using statistical techniques from the extreme value theory and the theory of multivariate regular variation. To the best of our knowledge, this is the first

High power pulsed sources based on fiber amplifiers

Science.gov (United States)

Canat, Guillaume; Jaouën, Yves; Mollier, Jean-Claude; Bouzinac, Jean-Pierre; Cariou, Jean-Pierre

2017-11-01

Cladding-pumped rare-earth-doped fiber laser technologies are currently among the best sources for high power applications. Theses extremely compact and robust sources appoint them as good candidate for aeronautical and space applications. The double-clad (DC) fiber converts the poor beamquality of high-power large-area pump diodes from the 1st cladding to laser light at another wavelength guided in an active single-mode core. High-power coherent MOPA (Master Oscillator Power Amplifier) sources (several 10W CW or several 100W in pulsed regime) will soon be achieved. Unfortunately it also brings nonlinear effects which quickly impairs output signal distortions. Stimulated Brillouin scattering (SBS) and optical parametric amplification (OPA) have been shown to be strong limitations. Based on amplifier modeling and experiments we discuss the performances of these sources.

Long-pulse applications of pulse-forming lines for high-power linac application

International Nuclear Information System (INIS)

Hoeberling, R.F.; Tallerico, P.J.

1981-01-01

The ever present demands for high efficiency in the RF power stations for particle accelerators have caused increased interest in longer RF pulses (ten's of microseconds) for linacs such as the Pion Generator for Medical Irradiation (PIGMI) and Free Electron Laser (FEL). For either RF power station, a fundamental decision is whether to use a modulating anode/hard-tube driver or pulsed cathode/line-type pulser configuration. The choices in the extremes of low power for very long pulses or for very-high-power, short pulses are, respectively, a modulated anode/hard tube modulator and pulsed cathode/pulse forming line. However, the demarcation between these two extremes is not clearcut. The criteria (cost, flexibility performance, reliability, efficiency) that resulted in the RF station definition of these two specific systems will be described

Probabilistic forecasting of wind power generation using extreme learning machine

DEFF Research Database (Denmark)

Wan, Can; Xu, Zhao; Pinson, Pierre

2014-01-01

an extreme learning machine (ELM)-based probabilistic forecasting method for wind power generation. To account for the uncertainties in the forecasting results, several bootstrapmethods have been compared for modeling the regression uncertainty, based on which the pairs bootstrap method is identified......Accurate and reliable forecast of wind power is essential to power system operation and control. However, due to the nonstationarity of wind power series, traditional point forecasting can hardly be accurate, leading to increased uncertainties and risks for system operation. This paper proposes...... with the best performance. Consequently, a new method for prediction intervals formulation based on theELMand the pairs bootstrap is developed.Wind power forecasting has been conducted in different seasons using the proposed approach with the historical wind power time series as the inputs alone. The results...

Supporting Control Room Operators in Highly Automated Future Power Networks

DEFF Research Database (Denmark)

Chen, Minjiang; Catterson, Victoria; Syed, Mazheruddin

2017-01-01

Operating power systems is an extremely challenging task, not least because power systems have become highly interconnected, as well as the range of network issues that can occur. It is therefore a necessity to develop decision support systems and visualisation that can effectively support the hu...... the human operators for decisionmaking in the complex and dynamic environment of future highly automated power system. This paper aims to investigate the decision support functions associated with frequency deviation events for the proposed Web of Cells concept....

Bright high-repetition-rate source of narrowband extreme-ultraviolet harmonics beyond 22 eV

Energy Technology Data Exchange (ETDEWEB)

Wang, He [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Xu, Yiming [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Ulonska, Stefan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Robinson, Joseph S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Ranitovic, Predrag [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Kaindl, Robert A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division

2015-06-11

Novel table-top sources of extreme-ultraviolet light based on high-harmonic generation yield unique insight into the fundamental properties of molecules, nanomaterials or correlated solids, and enable advanced applications in imaging or metrology. Extending high-harmonic generation to high repetition rates portends great experimental benefits, yet efficient extreme-ultraviolet conversion of correspondingly weak driving pulses is challenging. In this article, we demonstrate a highly-efficient source of femtosecond extreme-ultraviolet pulses at 50-kHz repetition rate, utilizing the ultraviolet second-harmonic focused tightly into Kr gas. In this cascaded scheme, a photon flux beyond ≈3 × 10¹³ s^-1 is generated at 22.3 eV, with 5 × 10^-5 conversion efficiency that surpasses similar harmonics directly driven by the fundamental by two orders-of-magnitude. The enhancement arises from both wavelength scaling of the atomic dipole and improved spatio-temporal phase matching, confirmed by simulations. Finally, spectral isolation of a single 72-meV-wide harmonic renders this bright, 50-kHz extreme-ultraviolet source a powerful tool for ultrafast photoemission, nanoscale imaging and other applications.

Impact of extreme load requirements and quality assurance on nuclear power plant costs

International Nuclear Information System (INIS)

Stevenson, J.D.

1993-01-01

Definitive costs, applicable to nuclear power plant concrete structures, as a function of National Regulatory Requirements, standardization, the effect of extreme load design associated with both design basis accidents and extreme external events and quality assurance are difficult to develop since such effects are interrelated and not only differ widely from country to country, project to project but also vary in time. Table 1 shows an estimate of the of the overall plant cost effects of external event extreme load design on nuclear power plant design for the U.S -and selected foreign countries for which experience with LWRs exist- Germany is the most expensive primarily due to a military aircraft crash resistance. However, the German requirement for 4 safeguards trains rather than 2 and the containment design requirement to consider one Steam Generator blowdown concurrent with a RCS blowdown. This presentation will concentrate on the direct current impact extreme load design and quality assurance have on concrete structures, systems and components for nuclear plants. This presentation is considered timely due to the increased interest in the c potential backfit of Eastern European nuclear power stations of the WWER 440 and WWER 1000 types which typically did not consider the extreme loads identified in Table 1 and accident loads in Table 3 and quality assurance in Table 5 in their original design. Concrete structures in particular are highlighted because they typically form the last barrier to radioactive release from the containment and other Safety Related Structures

Application of extreme value distribution function in the determination of standard meteorological parameters for nuclear power plants

International Nuclear Information System (INIS)

Jiang Haimei; Liu Xinjian; Qiu Lin; Li Fengju

2014-01-01

Based on the meteorological data from weather stations around several domestic nuclear power plants, the statistical results of extreme minimum temperatures, minimum. central pressures of tropical cyclones and some other parameters are calculated using extreme value I distribution function (EV- I), generalized extreme value distribution function (GEV) and generalized Pareto distribution function (GP), respectively. The influence of different distribution functions and parameter solution methods on the statistical results of extreme values is investigated. Results indicate that generalized extreme value function has better applicability than the other two distribution functions in the determination of standard meteorological parameters for nuclear power plants. (authors)

High power density reactors based on direct cooled particle beds

Science.gov (United States)

Powell, J. R.; Horn, F. L.

Reactors based on direct cooled High Temperature Gas Cooled Reactor (HTGR) type particle fuel are described. The small diameter particle fuel is packed between concentric porous cylinders to make annular fuel elements, with the inlet coolant gas flowing inwards. Hot exit gas flows out along the central channel of each element. Because of the very large heat transfer area in the packed beds, power densities in particle bed reactors (PBRs) are extremely high resulting in compact, lightweight systems. Coolant exit temperatures are high, because of the ceramic fuel temperature capabilities, and the reactors can be ramped to full power and temperature very rapidly. PBR systems can generate very high burst power levels using open cycle hydrogen coolant, or high continuous powers using closed cycle helium coolant. PBR technology is described and development requirements assessed.

High-Efficiency Isolated Boost DCDC Converter for High-Power Low-Voltage Fuel-Cell Applications

DEFF Research Database (Denmark)

Nymand, Morten; Andersen, Michael A. E.

2010-01-01

high winding losses. The analysis of transformer leakage inductance reveals that extremely low leakage inductance can be achieved, allowing stored energy to be dissipated. Power MOSFETs fully rated for repetitive avalanches allow primary-side voltage clamp circuits to be eliminated. The oversizing...

Adequacy of current systems for monitoring extremity exposures at nuclear power plants

International Nuclear Information System (INIS)

Reece, W.D.; Harty, R.

1985-01-01

In general, only a small portion of workers at commercial nuclear power plants are limited by extremity exposures, and these workers can be readily identified. There seems to be no need for increased badging among the radiation workers. However, those workers who are extremity limited may not be receiving adequate dosimetry. For workers handling compact sources, unless contrary information is available, the tip of the thumb of the dominant hand can be assumed to be the limiting site, and dose to the thumb tip averaged over one square centimeter at the basal layer of the skin should be measured or estimated. As discussed briefly in this paper, the assessment of dose in high gradient fields can be a difficult task. The particular dosimeter studied is a band-aid type composed of a thermoluminescent material embedded in a carbon matrix under 4 mils of plastic. Advantages and disadvantages of the technique are discussed

Operation of Power Grids with High Penetration of Wind Power

Science.gov (United States)

Al-Awami, Ali Taleb

The integration of wind power into the power grid poses many challenges due to its highly uncertain nature. This dissertation involves two main components related to the operation of power grids with high penetration of wind energy: wind-thermal stochastic dispatch and wind-thermal coordinated bidding in short-term electricity markets. In the first part, a stochastic dispatch (SD) algorithm is proposed that takes into account the stochastic nature of the wind power output. The uncertainty associated with wind power output given the forecast is characterized using conditional probability density functions (CPDF). Several functions are examined to characterize wind uncertainty including Beta, Weibull, Extreme Value, Generalized Extreme Value, and Mixed Gaussian distributions. The unique characteristics of the Mixed Gaussian distribution are then utilized to facilitate the speed of convergence of the SD algorithm. A case study is carried out to evaluate the effectiveness of the proposed algorithm. Then, the SD algorithm is extended to simultaneously optimize the system operating costs and emissions. A modified multi-objective particle swarm optimization algorithm is suggested to identify the Pareto-optimal solutions defined by the two conflicting objectives. A sensitivity analysis is carried out to study the effect of changing load level and imbalance cost factors on the Pareto front. In the second part of this dissertation, coordinated trading of wind and thermal energy is proposed to mitigate risks due to those uncertainties. The problem of wind-thermal coordinated trading is formulated as a mixed-integer stochastic linear program. The objective is to obtain the optimal tradeoff bidding strategy that maximizes the total expected profits while controlling trading risks. For risk control, a weighted term of the conditional value at risk (CVaR) is included in the objective function. The CVaR aims to maximize the expected profits of the least profitable scenarios, thus

Frontiers in pulse-power-based high energy density plasma physics and its applications

International Nuclear Information System (INIS)

Horioka, Kazuhiko

2008-03-01

The papers in this volume of report were presented at the Symposium on Frontiers in Pulse-power-based High Energy Density Physics' held by National Institute for Fusion Science. The topics include the present status of high energy density plasma researches, extreme ultraviolet sources, intense radiation sources, high power ion beams, and R and D of related pulse power technologies. The 13 of the presented papers are indexed individually. (J.P.N.)

Changes in lower extremity movement and power absorption during forefoot striking and barefoot running.

Science.gov (United States)

Williams, D S Blaise; Green, Douglas H; Wurzinger, Brian

2012-10-01

Both forefoot strike shod (FFS) and barefoot (BF) running styles result in different mechanics when compared to rearfoot strike (RFS) shod running. Additionally, running mechanics of FFS and BF running are similar to one another. Comparing the mechanical changes occurring in each of these patterns is necessary to understand potential benefits and risks of these running styles. The authors hypothesized that FFS and BF conditions would result in increased sagittal plane joint angles at initial contact and that FFS and BF conditions would demonstrate a shift in sagittal plane joint power from the knee to the ankle when compared to the RFS condition. Finally, total lower extremity power absorption will be least in BF and greatest in the RFS shod condition. The study included 10 male and 10 female RFS runners who completed 3-dimensional running analysis in 3 conditions: shod with RFS, shod with FFS, and BF. Variables were the angles of plantarflexion, knee flexion, and hip flexion at initial contact and peak sagittal plane joint power at the hip, knee, and ankle during stance phase. Running with a FFS pattern and BF resulted in significantly greater plantarflexion and significantly less negative knee power (absorption) when compared to shod RFS condition. FFS condition runners landed in the most plantarflexion and demonstrated the most peak ankle power absorption and lowest knee power absorption between the 3 conditions. BF and FFS conditions demonstrated decreased total lower extremity power absorption compared to the shod RFS condition but did not differ from one another. BF and FFS running result in reduced total lower extremity power, hip power and knee power and a shift of power absorption from the knee to the ankle. Alterations associated with BF running patterns are present in a FFS pattern when wearing shoes. Additionally, both patterns result in increased demand at the foot and ankle as compared to the knee.

High power density reactors based on direct cooled particle beds

International Nuclear Information System (INIS)

Powell, J.R.; Horn, F.L.

1985-01-01

Reactors based on direct cooled HTGR type particle fuel are described. The small diameter particle fuel is packed between concentric porous cylinders to make annular fuel elements, with the inlet coolant gas flowing inwards. Hot exit gas flows out long the central channel of each element. Because of the very large heat transfer area in the packed beds, power densities in particle bed reactors (PBR's) are extremely high resulting in compact, lightweight systems. Coolant exit temperatures are high, because of the ceramic fuel temperature capabilities, and the reactors can be ramped to full power and temperature very rapidly. PBR systems can generate very high burst power levels using open cycle hydrogen coolant, or high continuous powers using closed cycle helium coolant. PBR technology is described and development requirements assessed. 12 figs

Solar PV Power Forecasting Using Extreme Learning Machine and Information Fusion

OpenAIRE

Le Cadre , Hélène; Aravena , Ignacio; Papavasiliou , Anthony

2015-01-01

International audience; We provide a learning algorithm combining distributed Extreme Learning Machine and an information fusion rule based on the ag-gregation of experts advice, to build day ahead probabilistic solar PV power production forecasts. These forecasts use, apart from the current day solar PV power production, local meteorological inputs, the most valuable of which is shown to be precipitation. Experiments are then run in one French region, Provence-Alpes-Côte d'Azur, to evaluate ...

A plasma microlens for ultrashort high power lasers

Science.gov (United States)

Katzir, Yiftach; Eisenmann, Shmuel; Ferber, Yair; Zigler, Arie; Hubbard, Richard F.

2009-07-01

We present a technique for generation of miniature plasma lens system that can be used for focusing and collimating a high intensity femtosecond laser pulse. The plasma lens was created by a nanosecond laser, which ablated a capillary entrance. The spatial configuration of the ablated plasma focused a high intensity femtosecond laser pulse. This configuration offers versatility in the plasma lens small f-number for extremely tight focusing of high power lasers with no damage threshold restrictions of regular optical components.

A plasma microlens for ultrashort high power lasers

International Nuclear Information System (INIS)

Katzir, Yiftach; Eisenmann, Shmuel; Ferber, Yair; Zigler, Arie; Hubbard, Richard F.

2009-01-01

We present a technique for generation of miniature plasma lens system that can be used for focusing and collimating a high intensity femtosecond laser pulse. The plasma lens was created by a nanosecond laser, which ablated a capillary entrance. The spatial configuration of the ablated plasma focused a high intensity femtosecond laser pulse. This configuration offers versatility in the plasma lens small f-number for extremely tight focusing of high power lasers with no damage threshold restrictions of regular optical components.

A genome-wide analysis of putative functional and exonic variation associated with extremely high intelligence.

Science.gov (United States)

Spain, S L; Pedroso, I; Kadeva, N; Miller, M B; Iacono, W G; McGue, M; Stergiakouli, E; Davey Smith, G; Putallaz, M; Lubinski, D; Meaburn, E L; Plomin, R; Simpson, M A

2016-08-01

Although individual differences in intelligence (general cognitive ability) are highly heritable, molecular genetic analyses to date have had limited success in identifying specific loci responsible for its heritability. This study is the first to investigate exome variation in individuals of extremely high intelligence. Under the quantitative genetic model, sampling from the high extreme of the distribution should provide increased power to detect associations. We therefore performed a case-control association analysis with 1409 individuals drawn from the top 0.0003 (IQ >170) of the population distribution of intelligence and 3253 unselected population-based controls. Our analysis focused on putative functional exonic variants assayed on the Illumina HumanExome BeadChip. We did not observe any individual protein-altering variants that are reproducibly associated with extremely high intelligence and within the entire distribution of intelligence. Moreover, no significant associations were found for multiple rare alleles within individual genes. However, analyses using genome-wide similarity between unrelated individuals (genome-wide complex trait analysis) indicate that the genotyped functional protein-altering variation yields a heritability estimate of 17.4% (s.e. 1.7%) based on a liability model. In addition, investigation of nominally significant associations revealed fewer rare alleles associated with extremely high intelligence than would be expected under the null hypothesis. This observation is consistent with the hypothesis that rare functional alleles are more frequently detrimental than beneficial to intelligence.

EPS-LASSO: Test for High-Dimensional Regression Under Extreme Phenotype Sampling of Continuous Traits.

Science.gov (United States)

Xu, Chao; Fang, Jian; Shen, Hui; Wang, Yu-Ping; Deng, Hong-Wen

2018-01-25

Extreme phenotype sampling (EPS) is a broadly-used design to identify candidate genetic factors contributing to the variation of quantitative traits. By enriching the signals in extreme phenotypic samples, EPS can boost the association power compared to random sampling. Most existing statistical methods for EPS examine the genetic factors individually, despite many quantitative traits have multiple genetic factors underlying their variation. It is desirable to model the joint effects of genetic factors, which may increase the power and identify novel quantitative trait loci under EPS. The joint analysis of genetic data in high-dimensional situations requires specialized techniques, e.g., the least absolute shrinkage and selection operator (LASSO). Although there are extensive research and application related to LASSO, the statistical inference and testing for the sparse model under EPS remain unknown. We propose a novel sparse model (EPS-LASSO) with hypothesis test for high-dimensional regression under EPS based on a decorrelated score function. The comprehensive simulation shows EPS-LASSO outperforms existing methods with stable type I error and FDR control. EPS-LASSO can provide a consistent power for both low- and high-dimensional situations compared with the other methods dealing with high-dimensional situations. The power of EPS-LASSO is close to other low-dimensional methods when the causal effect sizes are small and is superior when the effects are large. Applying EPS-LASSO to a transcriptome-wide gene expression study for obesity reveals 10 significant body mass index associated genes. Our results indicate that EPS-LASSO is an effective method for EPS data analysis, which can account for correlated predictors. The source code is available at https://github.com/xu1912/EPSLASSO. hdeng2@tulane.edu. Supplementary data are available at Bioinformatics online. © The Author (2018). Published by Oxford University Press. All rights reserved. For Permissions, please

Foundations of high-energy-density physics physical processes of matter at extreme conditions

CERN Document Server

Larsen, Jon

2017-01-01

High-energy-density physics explores the dynamics of matter at extreme conditions. This encompasses temperatures and densities far greater than we experience on Earth. It applies to normal stars, exploding stars, active galaxies, and planetary interiors. High-energy-density matter is found on Earth in the explosion of nuclear weapons and in laboratories with high-powered lasers or pulsed-power machines. The physics explored in this book is the basis for large-scale simulation codes needed to interpret experimental results whether from astrophysical observations or laboratory-scale experiments. The key elements of high-energy-density physics covered are gas dynamics, ionization, thermal energy transport, and radiation transfer, intense electromagnetic waves, and their dynamical coupling. Implicit in this is a fundamental understanding of hydrodynamics, plasma physics, atomic physics, quantum mechanics, and electromagnetic theory. Beginning with a summary of the topics and exploring the major ones in depth, thi...

Using PROGUMBEL to predict extreme external hazards during nuclear power plant construction

International Nuclear Information System (INIS)

Diburg, S.; Hoelscher, N.; Niemann, H.J.; Meiswinkel, R.

2010-01-01

Safety considerations concerning the construction of power plants, supporting structure planning, safety concept and structural design require reliable data on external events, their incidence probability and characteristic parameters. The basis for supporting structure calculations based on probabilistic reliability considerations is the knowledge on the statistical distribution or the incidence frequency of specific phenomena and their characteristic basic variables. The extreme value statistics software PRO GUMBEL is the extended version of the original GUMBEL software used for seismic assessments. The authors describe the features of the software, that covers seismic events, flooding and extreme storms.

Solid state pump lasers with high power and high repetition rate

International Nuclear Information System (INIS)

Oba, Masaki; Kato, Masaaki; Arisawa, Takashi

1995-01-01

We built a laser diode pumped solid state green laser (LDPSSGL) rated at high repetition rate. Two laser heads are placed in one cavity with a rotator in between to design to avoid thermal lensing and thermal birefringence effect. Although average green laser power higher than 10 W was obtained at 1 kHz repetition rate with pulse width of 20-30 nsec, the beam quality was so much deteriorated that energy efficiency was as low as 2 %. Learning from this experience that high power oscillator causes a lot of thermal distortion not only in the laser rod but also in the Q-switch device, we proceeded to built a oscillator/amplifier system. A low power oscillator has a slab type crystal in the cavity. As a result spatial distribution of laser power was extremely improved. As we expect that the high repetition rate solid state laser should be CW operated Q-switch type laser from the view point of lifetime of diode lasers, a conventional arc lamp pumped CW Q-switch green YAG laser of which the repetition rate is changeable from 1 kHz to 5 kHz and the pulse width is 250-570 nsec was also tested to obtain pumping characteristics of a dye laser as a function of power, pulse width etc., and dye laser pulse width of 100-130 nsec were obtained. (author)

Solar PV power forecasting using extreme machine learning and experts advice fusion

OpenAIRE

Le Cadre, Hélène; Aravena Solís, Ignacio Andrés; Papavasiliou, Anthony; European Symposium on Artificial Neural Networks, Computational Intelligence and Machine Learning

2015-01-01

We provide a learning algorithm combining distributed Extreme Learning Machine and an information fusion rule based on the aggregation of experts advice, to build day ahead probabilistic solar PV power production forecasts. These forecasts use, apart from the current day solar PV power production, local meteorological inputs, the most valuable of which is shown to be precipitation. Experiments are then run in one French region, Provence-Alpes-Côte d’Azur, to evaluate the algorithm performance...

Normal and Extreme Wind Conditions for Power at Coastal Locations in China.

Science.gov (United States)

Gao, Meng; Ning, Jicai; Wu, Xiaoqing

2015-01-01

In this paper, the normal and extreme wind conditions for power at 12 coastal locations along China's coastline were investigated. For this purpose, the daily meteorological data measured at the standard 10-m height above ground for periods of 40-62 years are statistically analyzed. The East Asian Monsoon that affects almost China's entire coastal region is considered as the leading factor determining wind energy resources. For most stations, the mean wind speed is higher in winter and lower in summer. Meanwhile, the wind direction analysis indicates that the prevalent winds in summer are southerly, while those in winter are northerly. The air densities at different coastal locations differ significantly, resulting in the difference in wind power density. The Weibull and lognormal distributions are applied to fit the yearly wind speeds. The lognormal distribution performs better than the Weibull distribution at 8 coastal stations according to two judgement criteria, the Kolmogorov-Smirnov test and absolute error (AE). Regarding the annual maximum extreme wind speed, the generalized extreme value (GEV) distribution performs better than the commonly-used Gumbel distribution. At these southeastern coastal locations, strong winds usually occur in typhoon season. These 4 coastal provinces, that is, Guangdong, Fujian, Hainan, and Zhejiang, which have abundant wind resources, are also prone to typhoon disasters.

Extreme states of matter high energy density physics

CERN Document Server

Fortov, Vladimir E

2016-01-01

With its many beautiful colour pictures, this book gives fascinating insights into the unusual forms and behaviour of matter under extremely high pressures and temperatures. These extreme states are generated, among other things, by strong shock, detonation and electric explosion waves, dense laser beams,electron and ion beams, hypersonic entry of spacecraft into dense atmospheres of planets, and in many other situations characterized by extremely high pressures and temperatures.Written by one of the world's foremost experts on the topic, this book will inform and fascinate all scientists dealing with materials properties and physics, and also serve as an excellent introduction to plasma-, shock-wave and high-energy-density physics for students and newcomers seeking an overview. This second edition is thoroughly revised and expanded, in particular with new material on high energy-density physics, nuclear explosions and other nuclear transformation processes.

Extremely high efficiency phosphorescent organic light-emitting diodes with horizontal emitting dipoles

Science.gov (United States)

Kim, Kwon-Hyeon; Moon, Chang-Ki; Lee, Jeong-Hwan; Kim, Jang-Joo

2014-10-01

We present the factors influencing the orientation of the phosphorescent dyes in phosphorescent OLEDs. And, we report that an OLED containing a phosphorescent emitter with horizontally oriented dipoles in an exciplex-forming co-host that exhibits an extremely high EQE of 32.3% and power efficiency of 142 lm/W, the highest values ever reported in literature. Furthermore, we experimentally and theoretically correlated the EQE of OLEDs to the PL quantum yield and the horizontal dipole ratio of phosphorescent dyes using three different dyes.

Analysis of extreme hydrometric values in the nuclear power plants siting

International Nuclear Information System (INIS)

Gomez, H.R.; Maggio, G.E.; Tripoli, C.R.

1983-01-01

The atucha nuclear power plants are located on the right shore of the Parana de las Palmas river in the entire transition between a fluvial regime and other of tides. Since the disponibility of cooling water is one of the factors to take into account when choosing the nuclear power plant site, it is essential to perform a probabilistic study of extreme hydrometric values. Deterministic and historical analysis should be done to complete the studies already mentioned, in order to establish the values of probable maximum floods. From the application of these methods, it is concluded that the site of the Atucha nuclear power plants constitutes a hydrometric singularity, so that, an optimization has been obtained from that point of view. (Author) [es

LEVELS OF EXTREMELY LOW-FREQUENCY ELECTRIC AND MAGNETIC FIELDS FROM OVERHEAD POWER LINES IN THE OUTDOOR ENVIRONMENT OF RAMALLAH CITY-PALESTINE.

Science.gov (United States)

Abuasbi, Falastine; Lahham, Adnan; Abdel-Raziq, Issam Rashid

2018-05-01

In this study, levels of extremely low-frequency electric and magnetic fields originated from overhead power lines were investigated in the outdoor environment in Ramallah city, Palestine. Spot measurements were applied to record fields intensities over 6-min period. The Spectrum Analyzer NF-5035 was used to perform measurements at 1 m above ground level and directly underneath 40 randomly selected power lines distributed fairly within the city. Levels of electric fields varied depending on the line's category (power line, transformer or distributor), a minimum mean electric field of 3.9 V/m was found under a distributor line, and a maximum of 769.4 V/m under a high-voltage power line (66 kV). However, results of electric fields showed a log-normal distribution with the geometric mean and the geometric standard deviation of 35.9 and 2.8 V/m, respectively. Magnetic fields measured at power lines, on contrast, were not log-normally distributed; the minimum and maximum mean magnetic fields under power lines were 0.89 and 3.5 μT, respectively. As a result, none of the measured fields exceeded the ICNIRP's guidelines recommended for general public exposures to extremely low-frequency fields.

Vertical GaN Devices for Power Electronics in Extreme Environments

Science.gov (United States)

2016-03-31

Vertical GaN Devices for Power Electronics in Extreme Environments Isik C. Kizilyalli (1), Robert J. Kaplar (2), O. Aktas (1), A. M. Armstrong (2...electronics applications. In this paper vertical p-n diodes and transistors fabricated on pseudo bulk low defect density (104 to 106 cm-2) GaN substrates are...discussed. Homoepitaxial MOCVD growth of GaN on its native substrate and being able to control doping has allowed the realization of vertical

High Power Narrow Linewidth 1.26 Micron Ho-Doped Fiber Amplifier, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — This proposal is for the development of an innovative, high power, and extremely reliable 1.26-micron Ho-doped fluoride fiber amplifier. The proposed fiber amplifier...

High Power Narrow Linewidth 1.26 Micron Ho-Doped Fiber Amplifier, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This proposal is for the development of an innovative, high power, and extremely reliable 1.26-micron Ho-doped fluoride fiber amplifier. The proposed fiber amplifier...

High-Power Krypton Hall Thruster Technology Being Developed for Nuclear-Powered Applications

Science.gov (United States)

Jacobson, David T.; Manzella, David H.

2004-01-01

The NASA Glenn Research Center has been performing research and development of moderate specific impulse, xenon-fueled, high-power Hall thrusters for potential solar electric propulsion applications. These applications include Mars missions, reusable tugs for low-Earth-orbit to geosynchronous-Earth-orbit transportation, and missions that require transportation to libration points. This research and development effort resulted in the design and fabrication of the NASA-457M Hall thruster that has been tested at input powers up to 95 kW. During project year 2003, NASA established Project Prometheus to develop technology in the areas of nuclear power and propulsion, which are enabling for deep-space science missions. One of the Project-Prometheus-sponsored Nuclear Propulsion Research tasks is to investigate alternate propellants for high-power Hall thruster electric propulsion. The motivation for alternate propellants includes the disadvantageous cost and availability of xenon propellant for extremely large scale, xenon-fueled propulsion systems and the potential system performance benefits of using alternate propellants. The alternate propellant krypton was investigated because of its low cost relative to xenon. Krypton propellant also has potential performance benefits for deep-space missions because the theoretical specific impulse for a given voltage is 20 percent higher than for xenon because of krypton's lower molecular weight. During project year 2003, the performance of the high-power NASA-457M Hall thruster was measured using krypton as the propellant at power levels ranging from 6.4 to 72.5 kW. The thrust produced ranged from 0.3 to 2.5 N at a discharge specific impulse up to 4500 sec.

Experimental astrophysics with high power lasers and Z pinches

Energy Technology Data Exchange (ETDEWEB)

Remington, B A; Drake, R P; Ryutov, D D

2004-12-10

With the advent of high energy density (HED) experimental facilities, such as high-energy lasers and fast Z-pinch, pulsed-power facilities, mm-scale quantities of matter can be placed in extreme states of density, temperature, and/or velocity. This has enabled the emergence of a new class of experimental science, HED laboratory astrophysics, wherein the properties of matter and the processes that occur under extreme astrophysical conditions can be examined in the laboratory. Areas particularly suitable to this class of experimental astrophysics include the study of opacities relevant to stellar interiors; equations of state relevant to planetary interiors; strong shock driven nonlinear hydrodynamics and radiative dynamics, relevant to supernova explosions and subsequent evolution; protostellar jets and high Mach-number flows; radiatively driven molecular clouds and nonlinear photoevaporation front dynamics; and photoionized plasmas relevant to accretion disks around compact objects, such as black holes and neutron stars.

Extreme meteorological events in nuclear power plant siting, excluding tropical cyclones

International Nuclear Information System (INIS)

1981-01-01

This Safety Guide deals with the extremes of meteorological variables and the extreme meteorological phenomena in accordance with the general criteria of the Code. The Guide outlines a procedure based on the following steps: (1) The meteorological phenomena and variables are described and classified, according to their effects on safety. (2) Data sources are identified, and data are collected. (3) Meteorological variables such as air temperature are analysed to determine their design bases; and the design basis event in case of phenomena such as the design basis tornado is identified. (4) As appropriate, the design basis value for the variable, or the design basis for the phenomena (such as pressure drop and maximum wind speed of the design basis tornado), is defined. In the following sections, the general procedure for evaluating the design bases of extreme meteorological variables and phenomena is outlined. The procedure is then presented in detail for each variable or phenomenon considered. The variables characterizing the meteorological environment dealt with in this Guide are wind speed, atmospheric precipitation, and temperature. The extreme meteorological phenomena discussed here are the tornado and, briefly, the tropical cyclone, which is discussed more extensively in the Safety Guide on Design Basis Tropical Cyclone for Nuclear Power Plants (IAEA Safety Series No. 50-SG-S11B)

Power-law scaling of extreme dynamics near higher-order exceptional points

Science.gov (United States)

Zhong, Q.; Christodoulides, D. N.; Khajavikhan, M.; Makris, K. G.; El-Ganainy, R.

2018-02-01

We investigate the extreme dynamics of non-Hermitian systems near higher-order exceptional points in photonic networks constructed using the bosonic algebra method. We show that strong power oscillations for certain initial conditions can occur as a result of the peculiar eigenspace geometry and its dimensionality collapse near these singularities. By using complementary numerical and analytical approaches, we show that, in the parity-time (PT ) phase near exceptional points, the logarithm of the maximum optical power amplification scales linearly with the order of the exceptional point. We focus in our discussion on photonic systems, but we note that our results apply to other physical systems as well.

Consideration of Task Performance for Robots Engaged in Extremely Dangerous Environment in Nuclear Power Plants

Energy Technology Data Exchange (ETDEWEB)

Hong, Seung Mo; Han, Kee Soo; Yi, Sung Deok; Kim, Seoung Rae [Nuclear Engineering Service and Solution Co. Ltd., Daejeon (Korea, Republic of); Choi, Young [KAERI, Daejeon (Korea, Republic of)

2015-05-15

After Fukushima Daiichi Nuclear Accident, it is started to pay more attention to operation and accident of nuclear power plants (NPPs). For domestic nuclear industry, it was recommended to establish corresponding strategies against accidents due to extremely dangerous natural disasters. Each nuclear power plant is also preparing to establish strategies to secure nuclear safety functions by estimating the counterplans for extreme accidents. Robots are particularly being used to access the areas where those are dangerous for human beings to access or to restore the accident. Robot technologies in NPPs are emerging cutting-edge technologies that are just a start except the developed countries like USA, Japan, etc. But they are carefully considered because they have the advantages of performing tasks in extremely dangerous environment in NPPs instead of human beings. In this study, the applicability of robots will be considered in extremely dangerous environment in NPPs. Accurate judgment of the inside situation of the plant and quick actions in the extreme condition like earthquake accompanied by loss of all AC powers should be considered as major function in terms of prevention of accident spread. According to the reported stress test results of domestic NPPs, the difficult things for operators to carry out in extreme conditions can be predictable, therefore the active use of robots as accident mitigation strategies will be helpful to reduce the unnecessary spending for facility improvement. Current trend of domestic and foreign robot technology development focuses on the information search of the inside of the plant and development of preventive maintenance of NPPs. As seen actually in Fukushima Daiichi, main roles of robots place emphasis on measuring the inside radiation level accessing to the area where operator cannot access and delivering information which can support operator's decision-making and actions. Therefore, it is considered that development of

Automatic residue removal for high-NA extreme illumination

Science.gov (United States)

Moon, James; Nam, Byong-Sub; Jeong, Joo-Hong; Kong, Dong-Ho; Nam, Byung-Ho; Yim, Dong Gyu

2007-10-01

An epidemic for smaller node has been that, as the device architecture shrinks, lithography process requires high Numerical Aperture (NA), and extreme illumination system. This, in turn, creates many lithography problems such as low lithography process margin (Depth of Focus, Exposure Latitude), unstable Critical Dimension (CD) uniformity and restricted guideline for device design rule and so on. Especially for high NA, extreme illumination such as immersion illumination systems, above all the related problems, restricted design rule due to forbidden pitch is critical and crucial issue. This forbidden pitch is composed of numerous optical effects but majority of these forbidden pitch compose of photo resist residue and these residue must be removed to relieve some room for already tight design rule. In this study, we propose automated algorithm to remove photo resist residue due to high NA and extreme illumination condition. This algorithm automatically self assembles assist patterns based on the original design layout, therefore insuring the safety and simplicity of the generated assist pattern to the original design and removes any resist residue created by extreme illumination condition. Also we tested our automated algorithm on full chip FLASH memory device and showed the residue removal effect by using commercial verification tools as well as on actual test wafer.

Characterization and Aging Test Methodology for Power Electronic Devices at High Temperature

International Nuclear Information System (INIS)

Ibrahim, A.; Khatir, Z.; Dupont, L.

2011-01-01

Power electronic modules are key elements in the chain of power conversion. The application areas include aerospace, aviation, railway, electrical distribution, automotive, home automation, oil industry ... But the use of power electronics in high temperature environments is a major strategic issue in the coming years especially in transport. However, the active components based on silicon are limited in their applications and not suitable for those require both high voltages and high ambient temperatures. The materials with wide energy gap like SiC, GaN and diamond, have the advantage of being able to exceed these limits [1,2]. These materials seem adequate to extremely harsh temperature environments and allow the reduction of cooling systems, but also the increasing of switching frequency. (author)

Mechanical characterization of alloys in extreme conditions of high strain rates and high temperature

Science.gov (United States)

Cadoni, Ezio

2018-03-01

The aim of this paper is the description of the mechanical characterization of alloys under extreme conditions of temperature and loading. In fact, in the frame of the Cost Action CA15102 “Solutions for Critical Raw Materials Under Extreme Conditions (CRM-EXTREME)” this aspect is crucial and many industrial applications have to consider the dynamic response of materials. Indeed, for a reduction and substitution of CRMs in alloys is necessary to design the materials and understand if the new materials behave better or if the substitution or reduction badly affect their performance. For this reason, a deep knowledge of the mechanical behaviour at high strain-rates of considered materials is required. In general, machinery manufacturing industry or transport industry as well as energy industry have important dynamic phenomena that are simultaneously affected by extended strain, high strain-rate, damage and pressure, as well as conspicuous temperature gradients. The experimental results in extreme conditions of high strain rate and high temperature of an austenitic stainless steel as well as a high-chromium tempered martensitic reduced activation steel Eurofer97 are presented.

Performance of High Temperature Operational Amplifier, Type LM2904WH, under Extreme Temperatures

Science.gov (United States)

Patterson, Richard; Hammoud, Ahmad; Elbuluk, Malik

2008-01-01

Operation of electronic parts and circuits under extreme temperatures is anticipated in NASA space exploration missions as well as terrestrial applications. Exposure of electronics to extreme temperatures and wide-range thermal swings greatly affects their performance via induced changes in the semiconductor material properties, packaging and interconnects, or due to incompatibility issues between interfaces that result from thermal expansion/contraction mismatch. Electronics that are designed to withstand operation and perform efficiently in extreme temperatures would mitigate risks for failure due to thermal stresses and, therefore, improve system reliability. In addition, they contribute to reducing system size and weight, simplifying its design, and reducing development cost through the elimination of otherwise required thermal control elements for proper ambient operation. A large DC voltage gain (100 dB) operational amplifier with a maximum junction temperature of 150 C was recently introduced by STMicroelectronics [1]. This LM2904WH chip comes in a plastic package and is designed specifically for automotive and industrial control systems. It operates from a single power supply over a wide range of voltages, and it consists of two independent, high gain, internally frequency compensated operational amplifiers. Table I shows some of the device manufacturer s specifications.

CAS Accelerator Physics (High-Power Hadron Machines) in Spain

CERN Multimedia

CAS

2011-01-01

The CERN Accelerator School (CAS) and ESS-Bilbao jointly organised a specialised course on High-Power Hadron Machines, held at the Hotel Barceló Nervión in Bilbao, Spain, from 24 May to 2 June, 2011.   CERN Accelerator School students. After recapitulation lectures on the essentials of accelerator physics and review lectures on the different types of accelerators, the programme focussed on the challenges of designing and operating high-power facilities. The particular problems for RF systems, beam instrumentation, vacuum, cryogenics, collimators and beam dumps were examined. Activation of equipment, radioprotection and remote handling issues were also addressed. The school was very successful, with 69 participants of 22 nationalities. Feedback from the participants was extremely positive, praising the expertise and enthusiasm of the lecturers, as well as the high standard and excellent quality of their lectures. In addition to the academic programme, the participants w...

Assessment of Extremely Low Frequency (ELF Electric and Magnetic Fields in Hamedan High Electrical Power Stations and their Effects on Workers

Directory of Open Access Journals (Sweden)

Farshid Ghorbani Shahna

2011-09-01

Full Text Available Introduction: Public and occupational exposure to extremely low frequency (ELF electric and magnetic fields induced by electrical equipment is a significant issue in the environment and at the workplace due to their potential health effects on public health. The purpose of this study was assessment of the electric and magnetic fields intensities and determination of mental and psychological effects of occupational exposure in the high voltage electric power stations in the city of Hamadan, Iran. Material and Methods: The intensities of the magnetic and electric fields were measured at eight high voltage electric power stations at three different intervals of sources using an HI-3604 instrument. A two-part questionnaire was used to assess mental and psychological effects of the exposure to these fields. Two groups of control and case workers including 30 samples were selected to determine the exposure effects. Results: The results of field measurements showed the highest average electric field intensity was related to the CVT unit with 3110 V/m at a 2 m distance from the source and the lowest average was related to the control room with 1.35 V/m next to the source. Also, the highest and lowest magnetic field intensities were close to the transformator 2 and the battery room (50.42 and 1.31 mG, respectively. Discussion and Conclusion: The intensities of electric and magnetic fields in the selected stations are lower than the ACGIH and ICNIRP standard levels for occupational exposures. The results obtained indicate that the distribution of these fields was nonlinear around the sources and the effects observed on exposed workers were non-thermal.

Extreme value analysis of meteorological parameters observed during the period 1994-2001 at Kakrapar Atomic Power Station

International Nuclear Information System (INIS)

Ramkumar, S.; Dole, M.L.; Nankar, D.P.; Rajan, M.P.; Gurg, R.P.

2003-01-01

In the design of engineering structures, an understanding of extreme weather conditions that may occur at the site of interest is very essential, so that the structures can be designed to withstand such situations. In this report an analysis of extreme values of meteorological parameters observed at Kakrapar Atomic Power Station site for the period 1994 -2001 is described. The parameters considered are maximum and minimum air temperature, maximum wind speed and gust, and maximum rainfall in a month, in a day, in an hour and annual rainfall. The extreme value analysis reveals that annual rainfall, maximum monthly rainfall, minimum air temperature and maximum wind speed at 10 m obey Fisher-Tippet Type -1 distribution whereas maximum daily rainfall, maximum hourly rainfall, maxinlum air temperature and maximum wind speed at 30 m obey Fisher-Tippet Type -2 distribution function. There is no difference in correlation coefficients and fit both extreme value distribution function. Co-efficients of the distribution functions for each variable are established. Extreme values of parameters corresponding to return periods of 50 and 100 years are derived. These derived extreme values are particularly useful for arriving at suitable design basis values to ensure the safety of any civil structure in and around Kakrapar Atomic Power Station site with respect to stresses due to weather conditions. (author)

Optimized Extreme Learning Machine for Power System Transient Stability Prediction Using Synchrophasors

Directory of Open Access Journals (Sweden)

Yanjun Zhang

2015-01-01

Full Text Available A new optimized extreme learning machine- (ELM- based method for power system transient stability prediction (TSP using synchrophasors is presented in this paper. First, the input features symbolizing the transient stability of power systems are extracted from synchronized measurements. Then, an ELM classifier is employed to build the TSP model. And finally, the optimal parameters of the model are optimized by using the improved particle swarm optimization (IPSO algorithm. The novelty of the proposal is in the fact that it improves the prediction performance of the ELM-based TSP model by using IPSO to optimize the parameters of the model with synchrophasors. And finally, based on the test results on both IEEE 39-bus system and a large-scale real power system, the correctness and validity of the presented approach are verified.

High Efficiency Power Converter for Low Voltage High Power Applications

DEFF Research Database (Denmark)

Nymand, Morten

The topic of this thesis is the design of high efficiency power electronic dc-to-dc converters for high-power, low-input-voltage to high-output-voltage applications. These converters are increasingly required for emerging sustainable energy systems such as fuel cell, battery or photo voltaic based......, and remote power generation for light towers, camper vans, boats, beacons, and buoys etc. A review of current state-of-the-art is presented. The best performing converters achieve moderately high peak efficiencies at high input voltage and medium power level. However, system dimensioning and cost are often...

Reliability of offshore wind power production under extreme wind conditions. Deliverable D 9.5. Work Package 9: Electrical grid

DEFF Research Database (Denmark)

Cutululis, Nicolaos Antonio; Zeni, Lorenzo

years, with each year simulated with five random seeds, leading to a total of 25 annual wind power time series for six large offshore wind farms, summing up to a little over 330 wind turbines. Two storm control strategies were used. The analysis involved several aspects inspired from reliability studies....... The aspects investigated are storm events occurrences and durations, storm control strategy impact on the capacity factor (lost production), the loss of production (power produced from wind drops below a certain threshold due to high wind speeds and storm controller) and finally, the wind power production......Reliability of offshore wind production under extreme wind conditions was investigated in this report. The wind power variability from existing and future large offshore wind farms in Western Denmark were simulated using the Correlated Wind model developed at Risø. The analysis was done for five...

Polygenic determinants in extremes of high-density lipoprotein cholesterol.

Science.gov (United States)

Dron, Jacqueline S; Wang, Jian; Low-Kam, Cécile; Khetarpal, Sumeet A; Robinson, John F; McIntyre, Adam D; Ban, Matthew R; Cao, Henian; Rhainds, David; Dubé, Marie-Pierre; Rader, Daniel J; Lettre, Guillaume; Tardif, Jean-Claude; Hegele, Robert A

2017-11-01

HDL cholesterol (HDL-C) remains a superior biochemical predictor of CVD risk, but its genetic basis is incompletely defined. In patients with extreme HDL-C concentrations, we concurrently evaluated the contributions of multiple large- and small-effect genetic variants. In a discovery cohort of 255 unrelated lipid clinic patients with extreme HDL-C levels, we used a targeted next-generation sequencing panel to evaluate rare variants in known HDL metabolism genes, simultaneously with common variants bundled into a polygenic trait score. Two additional cohorts were used for validation and included 1,746 individuals from the Montréal Heart Institute Biobank and 1,048 individuals from the University of Pennsylvania. Findings were consistent between cohorts: we found rare heterozygous large-effect variants in 18.7% and 10.9% of low- and high-HDL-C patients, respectively. We also found common variant accumulation, indicated by extreme polygenic trait scores, in an additional 12.8% and 19.3% of overall cases of low- and high-HDL-C extremes, respectively. Thus, the genetic basis of extreme HDL-C concentrations encountered clinically is frequently polygenic, with contributions from both rare large-effect and common small-effect variants. Multiple types of genetic variants should be considered as contributing factors in patients with extreme dyslipidemia. Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.

Development of high power pumping system for capillary discharge EUV laser

International Nuclear Information System (INIS)

Sakai, Yusuke; Komatsu, Takanori; Watanabe, Masato; Okino, Akitoshi; Hotta, Eiki

2008-01-01

Development of high power pumping system for capillary discharge soft X-ray laser is reported. The pulsed power system consists of a 2.2 μF LC generator, a 2:54 step-up transformer and a 3 nF water capacitor. Taking advantage of high efficiency configuration, step-up ratio of water capacitor voltage to LC generator initial voltage is about 40 times. Consequently, obtained water capacitor voltage reaches about 450 kV when LC generator was charged to 12.5 kV. As a consequent, possibility of charging a water capacitor to 1 MV is demonstrated. With this extremely compact system, discharge current could be increased to nearly 100 kA through moderately long capillary, which leads to generation of high-density and high-temperature plasma column in order to realize EUV laser. (author)

QED studies using high-power lasers

International Nuclear Information System (INIS)

Mattias Marklund

2010-01-01

Complete text of publication follows. The event of extreme lasers, which intensities above 10 22 W/cm 2 will be reached on a routine basis, will give us opportunities to probe new aspects of quantum electrodynamics. In particular, the non-trivial properties of the quantum vacuum can be investigated as we reach previously unattainable laser intensities. Effects such as vacuum birefringence and pair production in strong fields could thus be probed. The prospects of obtaining new insights regarding the non-perturbative structure of quantum field theories shows that the next generation laser facilities can be important tool for fundamental physical studies. Here we aim at giving a brief overview of such aspects of high-power laser physics.

High-power ultrasonic treatment of contaminated soils and sediments

International Nuclear Information System (INIS)

Collings, A.F.; Gwan, P.B.; Sosa Pintos, A.P.

2004-01-01

Full text: The propagation of high-power ultrasound through a liquid can initiate the phenomenon of cavitation. This occurs with the collapse of gas bubbles formed during the rarefaction phase of the ultrasonic wave either from the dissolution of air or vaporisation of the liquid. Bubble collapse can generate localised temperatures up to 5,000 K and pressures up to 1,000 atmospheres. Solid particles in slurry have been shown to act as foci for the nucleation and collapse of bubbles. Theory and experiment have confirmed that the rupture of a bubble on a solid surface generates a high speed jet directed towards the surface. In this case, the extreme conditions generated by the non-linear shock wave produced by bubble collapse are localised on the solid surface. Since Persistent Organic Pollutants (POPs) are hydrophobic and are also readily absorbed on the surface of soil particles, the energy released by cavitation in a soil or sediment slurry is selectively directed towards them. The temperatures are sufficient to decompose these molecules. However, the extreme conditions are highly localised and the bulk solution temperature is essentially unaffected. Any decomposition products are immediately quenched and recombination reactions are avoided. Recent advances in ultrasound technology have produced commercial equipment capable of high power which has enabled us to remediate soils and sediments containing Organochlorine Pesticides (OCPs), Polyaromatic Hydrocarbons (PAHs) and Polychlorinated Biphenyls (PCBs). With reductions greater than 80% within minutes, this technique shows great promise with advantages of on-site treatment and reduced operating and capital costs compared with conventional methods

Extremely high concentration of folates in premature newborns.

Science.gov (United States)

Zikavska, T; Brucknerova, I

2014-01-01

Extremely high concentration of folates in premature newborns: case reports. Folates are a group of water soluble compounds, which are important for metabolic processes in human body. These are important during periods of rapid cell growth. The most accurate indicator of long-term folate level status in the body is the determination of red blood cell (RBC) folate concentrations. The optimal level of RBC folate is not known in neonatal period. Authors discuss the reasons for extremely high level of RBC folate concentrations. In our work we present the cases of two premature newborns with extremely high level of RBC folate concentrations, which were analyzed immunochemically on the first day of life and after six weeks of life. In both cases we measured RBC folate concentrations on the 1st day of life. After 6 weeks we found extremely high RBC folate concentration level (5516.67 ng/ml) in the first case after RBC transfusions. In second case after two months of life the RBC folate concentration level was doubled (2335.1 ng/ml) until 24 hours after RBC transfusion compared to levels after birth. The normal range of RBC folate values vary in newborns. The upper limit of daily dose of folic acid in pregnancy and neonatal period is not known. On the other hand it is an easily excreted water-soluble vitamin but in premature newborn it can lead to the disruption of metabolic balance and slow its degradation. Some factors can have an impact on RBC folate concentration. Blood transfusion can be one of the main influences on RBC folate concentration. To clarify these mechanisms further studies are required (Ref. 29).

Survey of extreme load design regulatory agency licensing requirements for nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Stevenson, J D

1976-04-01

Since 1965, when extreme load requirements began to be considered explicitly in nuclear power plant design, there has been a gradual divergence in requirements imposed by national regulatory agencies. However, nuclear plant safety is an international problem because of the potential international effects of any postulated plant failure. For this reason this paper has been prepared in an attempt to highlight the differences in national criteria currently used in the extreme load design of nuclear plant facilities. No attempt has been made to evaluate the relative merit of the criteria established by the various national regulatory agencies. This paper presents the results of a recent survey made of national atomic energy regulatory agencies and major nuclear steam supply design agencies, which requested a summary of current licensing criteria associated with earthquake, extreme wind (tornado), flood, airplane crash and accident (pipe break) loads applicable within the various national jurisdictions. Also presented are a number of comparisons which are meant to illustrate the differences in national regulatory criteria.

Survey of extreme load design regulatory agency licensing requirements for nuclear power plants

International Nuclear Information System (INIS)

Stevenson, J.D.

1976-01-01

Since 1965, when extreme load requirements began to be considered explicitly in nuclear power plant design, there has been a gradual divergence in requirements imposed by national regulatory agencies. However, nuclear plant safety is an international problem because of the potential international effects of any postulated plant failure. For this reason this paper has been prepared in an attempt to highlight the differences in national criteria currently used in the extreme load design of nuclear plant facilities. No attempt has been made to evaluate the relative merit of the criteria established by the various national regulatory agencies. This paper presents the results of a recent survey made of national atomic energy regulatory agencies and major nuclear steam supply design agencies, which requested a summary of current licensing criteria associated with earthquake, extreme wind (tornado), flood, airplane crash and accident (pipe break) loads applicable within the various national jurisdictions. Also presented are a number of comparisons which are meant to illustrate the differences in national regulatory criteria. (Auth.)

Power/energy use cases for high performance computing

Energy Technology Data Exchange (ETDEWEB)

Laros, James H. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kelly, Suzanne M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hammond, Steven [National Renewable Energy Lab. (NREL), Golden, CO (United States); Elmore, Ryan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Munch, Kristin [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2013-12-01

Power and Energy have been identified as a first order challenge for future extreme scale high performance computing (HPC) systems. In practice the breakthroughs will need to be provided by the hardware vendors. But to make the best use of the solutions in an HPC environment, it will likely require periodic tuning by facility operators and software components. This document describes the actions and interactions needed to maximize power resources. It strives to cover the entire operational space in which an HPC system occupies. The descriptions are presented as formal use cases, as documented in the Unified Modeling Language Specification [1]. The document is intended to provide a common understanding to the HPC community of the necessary management and control capabilities. Assuming a common understanding can be achieved, the next step will be to develop a set of Application Programing Interfaces (APIs) to which hardware vendors and software developers could utilize to steer power consumption.

Suction is kid's play: extremely fast suction in newborn seahorses

Science.gov (United States)

Van Wassenbergh, Sam; Roos, Gert; Genbrugge, Annelies; Leysen, Heleen; Aerts, Peter; Adriaens, Dominique; Herrel, Anthony

2009-01-01

Ongoing anatomical development typically results in a gradual maturation of the feeding movements from larval to adult fishes. Adult seahorses are known to capture prey by rotating their long-snouted head extremely quickly towards prey, followed by powerful suction. This type of suction is powered by elastic recoil and requires very precise coordination of the movements of the associated feeding structures, making it an all-or-none phenomenon. Here, we show that newborn Hippocampus reidi are able to successfully feed using an extremely rapid and powerful snout rotation combined with a high-volume suction, surpassing that observed in adult seahorses. An inverse dynamic analysis shows that an elastic recoil mechanism is also used to power head rotation in newborn H. reidi. This illustrates how extreme levels of performance in highly complex musculoskeletal systems can be present at birth given a delayed birth and rapid development of functionally important structures. The fact that the head skeleton of newborn seahorses is still largely cartilaginous may not be problematic because the hydrodynamic stress on the rotating snout appeared considerably lower than in adult syngnathids. PMID:19324657

Inelastic X-ray scattering experiments at extreme conditions: high temperatures and high pressures

Directory of Open Access Journals (Sweden)

S.Hosokawa

2008-03-01

Full Text Available In this article, we review the present status of experimental techniques under extreme conditions of high temperature and high pressure used for inelastic X-ray scattering (IXS experiments of liquid metals, semiconductors, molten salts, molecular liquids, and supercritical water and methanol. For high temperature experiments, some types of single-crystal sapphire cells were designed depending on the temperature of interest and the sample thickness for the X-ray transmission. Single-crystal diamond X-ray windows attached to the externally heated high-pressure vessel were used for the IXS experiment of supercritical water and methanol. Some typical experimental results are also given, and the perspective of IXS technique under extreme conditions is discussed.

Polygenic determinants in extremes of high-density lipoprotein cholesterol[S

Science.gov (United States)

Dron, Jacqueline S.; Wang, Jian; Low-Kam, Cécile; Khetarpal, Sumeet A.; Robinson, John F.; McIntyre, Adam D.; Ban, Matthew R.; Cao, Henian; Rhainds, David; Dubé, Marie-Pierre; Rader, Daniel J.; Lettre, Guillaume; Tardif, Jean-Claude

2017-01-01

HDL cholesterol (HDL-C) remains a superior biochemical predictor of CVD risk, but its genetic basis is incompletely defined. In patients with extreme HDL-C concentrations, we concurrently evaluated the contributions of multiple large- and small-effect genetic variants. In a discovery cohort of 255 unrelated lipid clinic patients with extreme HDL-C levels, we used a targeted next-generation sequencing panel to evaluate rare variants in known HDL metabolism genes, simultaneously with common variants bundled into a polygenic trait score. Two additional cohorts were used for validation and included 1,746 individuals from the Montréal Heart Institute Biobank and 1,048 individuals from the University of Pennsylvania. Findings were consistent between cohorts: we found rare heterozygous large-effect variants in 18.7% and 10.9% of low- and high-HDL-C patients, respectively. We also found common variant accumulation, indicated by extreme polygenic trait scores, in an additional 12.8% and 19.3% of overall cases of low- and high-HDL-C extremes, respectively. Thus, the genetic basis of extreme HDL-C concentrations encountered clinically is frequently polygenic, with contributions from both rare large-effect and common small-effect variants. Multiple types of genetic variants should be considered as contributing factors in patients with extreme dyslipidemia. PMID:28870971

High resolution spectroscopy of six new extreme helium stars

Science.gov (United States)

Heber, U.; Jones, G.; Drilling, J. S.

1986-01-01

High resolution spectra of six newly discovered extreme helium stars are presented. LSS 5121 is shown to be a spectroscopical twin of the hot extreme helium star HD 160641. A preliminary LTE analysis of LSS 3184 yielded an effective temperature of 22,000 K and a surface gravity of log g = 3.2. Four stars form a new subgroup, classified by sharp-lined He I spectra and pronounced O II spectra, and it is conjectured that these lie close to the Eddington limit. The whole group of extreme helium stars apparently is inhomogeneous with respect to luminosity to mass ratio and chemical composition.

On generation of high power x-rays in the range 7-20 keV

International Nuclear Information System (INIS)

Ratakhin, N.A.

1997-01-01

An attempt is made on the base of general relations to evaluate possibility of two approaches to the problem of receiving powerful x-radiation id spectral range of (7-20) keV. Extremely cut possibilities of electron beams of vacuum diodes and Z-pinch plasma thermal radiation are shown. Some perspectives of increasing such radiation power in connection with possibility of generation of high-energy electrons in Z-pinch plasma are noted

Invited Article: Visualisation of extreme value events in optical communications

Science.gov (United States)

Derevyanko, Stanislav; Redyuk, Alexey; Vergeles, Sergey; Turitsyn, Sergei

2018-06-01

Fluctuations of a temporal signal propagating along long-haul transoceanic scale fiber links can be visualised in the spatio-temporal domain drawing visual analogy with ocean waves. Substantial overlapping of information symbols or use of multi-frequency signals leads to strong statistical deviations of local peak power from an average signal power level. We consider long-haul optical communication systems from this unusual angle, treating them as physical systems with a huge number of random statistical events, including extreme value fluctuations that potentially might affect the quality of data transmission. We apply the well-established concepts of adaptive wavefront shaping used in imaging through turbid medium to detect the detrimental phase modulated sequences in optical communications that can cause extreme power outages (rare optical waves of ultra-high amplitude) during propagation down the ultra-long fiber line. We illustrate the concept by a theoretical analysis of rare events of high-intensity fluctuations—optical freak waves, taking as an example an increasingly popular optical frequency division multiplexing data format where the problem of high peak to average power ratio is the most acute. We also show how such short living extreme value spikes in the optical data streams are affected by nonlinearity and demonstrate the negative impact of such events on the system performance.

Workshop on extremely high energy density plasmas and their diagnostics

Energy Technology Data Exchange (ETDEWEB)

Ishii, Shozo (ed.)

2001-09-01

Compiled are the papers presented at the workshop on 'Extremely High Energy Density Plasmas and Their Diagnostics' held at National Institute for Fusion Science. The papers cover physics and applications of extremely high-energy density plasmas such as dense z-pinch, plasma focus, and intense pulsed charged beams. Separate abstracts were presented for 7 of the papers in this report. The remaining 25 were considered outside the subject scope of INIS. (author)

Workshop on extremely high energy density plasmas and their diagnostics

International Nuclear Information System (INIS)

Ishii, Shozo

2001-09-01

Compiled are the papers presented at the workshop on 'Extremely High Energy Density Plasmas and Their Diagnostics' held at National Institute for Fusion Science. The papers cover physics and applications of extremely high-energy density plasmas such as dense z-pinch, plasma focus, and intense pulsed charged beams. Separate abstracts were presented for 7 of the papers in this report. The remaining 25 were considered outside the subject scope of INIS. (author)

Extremely-high vacuum pressure measurement by laser ionization

International Nuclear Information System (INIS)

Kokubun, Kiyohide

1991-01-01

Laser ionization method has the very high sensitivity for detecting atoms and molecules. Hurst et al. successfully detected a single Cs atom by means of resonance ionization spectroscopy developed by them. Noting this high sensitivity, the authors have attempted to apply the laser ionization method to measure gas pressure, particularly in the range down to extremely high vacuum. At present, hot cathode ionization gauges are used for measuring gas pressure down to ultrahigh vacuum, however, those have a number of disadvantages. The pressure measurement using lasers does not have such disadvantages. The pressure measurement utilizing the laser ionization method is based on the principle that when laser beam is focused through a lens, the amount of atom or molecule ions generated in the focused space region is proportional to gas pressure. In this paper, the experimental results are presented on the nonresonant multiphoton ionization characteristics of various kinds of gases, the ion detection system with high sensitivity and an extremely high vacuum system prepared for the laser ionization experiment. (K.I.)

Extremely high frequency RF effects on electronics.

Energy Technology Data Exchange (ETDEWEB)

Loubriel, Guillermo Manuel; Vigliano, David; Coleman, Phillip Dale; Williams, Jeffery Thomas; Wouters, Gregg A.; Bacon, Larry Donald; Mar, Alan

2012-01-01

The objective of this work was to understand the fundamental physics of extremely high frequency RF effects on electronics. To accomplish this objective, we produced models, conducted simulations, and performed measurements to identify the mechanisms of effects as frequency increases into the millimeter-wave regime. Our purpose was to answer the questions, 'What are the tradeoffs between coupling, transmission losses, and device responses as frequency increases?', and, 'How high in frequency do effects on electronic systems continue to occur?' Using full wave electromagnetics codes and a transmission-line/circuit code, we investigated how extremely high-frequency RF propagates on wires and printed circuit board traces. We investigated both field-to-wire coupling and direct illumination of printed circuit boards to determine the significant mechanisms for inducing currents at device terminals. We measured coupling to wires and attenuation along wires for comparison to the simulations, looking at plane-wave coupling as it launches modes onto single and multiconductor structures. We simulated the response of discrete and integrated circuit semiconductor devices to those high-frequency currents and voltages, using SGFramework, the open-source General-purpose Semiconductor Simulator (gss), and Sandia's Charon semiconductor device physics codes. This report documents our findings.

High Efficiency Power Converter for Low Voltage High Power Applications

DEFF Research Database (Denmark)

Nymand, Morten

The topic of this thesis is the design of high efficiency power electronic dc-to-dc converters for high-power, low-input-voltage to high-output-voltage applications. These converters are increasingly required for emerging sustainable energy systems such as fuel cell, battery or photo voltaic based...

β-Cobalt sulfide nanoparticles decorated graphene composite electrodes for high capacity and power supercapacitors

Science.gov (United States)

Qu, Baihua; Chen, Yuejiao; Zhang, Ming; Hu, Lingling; Lei, Danni; Lu, Bingan; Li, Qiuhong; Wang, Yanguo; Chen, Libao; Wang, Taihong

2012-11-01

Electrochemical supercapacitors have drawn much attention because of their high power and reasonably high energy densities. However, their performances still do not reach the demand of energy storage. In this paper β-cobalt sulfide nanoparticles were homogeneously distributed on a highly conductive graphene (CS-G) nanocomposite, which was confirmed by transmission electron microscopy analysis, and exhibit excellent electrochemical performances including extremely high values of specific capacitance (~1535 F g-1) at a current density of 2 A g-1, high-power density (11.98 kW kg-1) at a discharge current density of 40 A g-1 and excellent cyclic stability. The excellent electrochemical performances could be attributed to the graphene nanosheets (GNSs) which could maintain the mechanical integrity. Also the CS-G nanocomposite electrodes have high electrical conductivity. These results indicate that high electronic conductivity of graphene nanocomposite materials is crucial to achieving high power and energy density for supercapacitors.

β-Cobalt sulfide nanoparticles decorated graphene composite electrodes for high capacity and power supercapacitors.

Science.gov (United States)

Qu, Baihua; Chen, Yuejiao; Zhang, Ming; Hu, Lingling; Lei, Danni; Lu, Bingan; Li, Qiuhong; Wang, Yanguo; Chen, Libao; Wang, Taihong

2012-12-21

Electrochemical supercapacitors have drawn much attention because of their high power and reasonably high energy densities. However, their performances still do not reach the demand of energy storage. In this paper β-cobalt sulfide nanoparticles were homogeneously distributed on a highly conductive graphene (CS-G) nanocomposite, which was confirmed by transmission electron microscopy analysis, and exhibit excellent electrochemical performances including extremely high values of specific capacitance (~1535 F g(-1)) at a current density of 2 A g(-1), high-power density (11.98 kW kg(-1)) at a discharge current density of 40 A g(-1) and excellent cyclic stability. The excellent electrochemical performances could be attributed to the graphene nanosheets (GNSs) which could maintain the mechanical integrity. Also the CS-G nanocomposite electrodes have high electrical conductivity. These results indicate that high electronic conductivity of graphene nanocomposite materials is crucial to achieving high power and energy density for supercapacitors.

Coupled-Multiplier Accelerator Produces High-Power Electron Beams for Industrial Applications

International Nuclear Information System (INIS)

Hatridge, M.; McIntyre, P.; Roberson, S.; Sattarov, A.; Thomas, E.; Meitzler, Charles

2003-01-01

The coupled multiplier is a new approach to efficient generation of MeV d.c. power for accelerator applications. High voltage is produced by a series of modules, each of which consists of a high-power alternator, step-up transformer, and 3-phase multiplier circuit. The alternators are connected mechanically along a rotating shaft, and connected by insulating flexible couplers. This approach differs from all previous d.c. technologies in that power is delivered to the various stages of the system mechanically, rather than through capacitive or inductive electrical coupling. For this reason the capital cost depends linearly on required voltage and power, rather than quadratically as with conventional technologies. The CM technology enables multiple electron beams to be driven within a common supply and insulating housing. MeV electron beam is extremely effective in decomposing organic contaminants in water. A 1 MeV, 100 kW industrial accelerator using the CM technology has been built and is being installed for treatment of wastewater at a petrochemical plant

Micro/Nano Fabricated Solid-State Thermoelectric Generator Devices for Integrated High Voltage Power Sources

Science.gov (United States)

Fleurial, J.-P.; Ryan, M. A.; Snyder, G. J.; Huang, C.-K.; Whitacre, J. F.; Patel, J.; Lim, J.; Borshchevsky, A.

2002-01-01

Deep space missions have a strong need for compact, high power density, reliable and long life electrical power generation and storage under extreme temperature conditions. Except for electrochemical batteries and solar cells, there are currently no available miniaturized power sources. Conventional power generators devices become inefficient in extreme environments (such as encountered in Mars, Venus or outer planet missions) and rechargeable energy storage devices can only be operated in a narrow temperature range thereby limiting mission duration. The planned development of much smaller spacecrafts incorporating a variety of micro/nanodevices and miniature vehicles will require novel, reliable power technologies. It is also expected that such micro power sources could have a wide range of terrestrial applications, in particular when the limited lifetime and environmental limitations of batteries are key factors. Advanced solid-state thermoelectric combined with radioisotope or waste heat sources and low profile energy storage devices are ideally suited for these applications. The Jet Propulsion Laboratory has been actively pursuing the development of thermoelectric micro/nanodevices that can be fabricated using a combination of electrochemical deposition and integrated circuit processing techniques. Some of the technical challenges associated with these micro/nanodevice concepts, their expected level of performance and experimental fabrication and testing results to date are presented and discussed.

Solidification at the High and Low Rate Extreme

Energy Technology Data Exchange (ETDEWEB)

Meco, Halim [Iowa State Univ., Ames, IA (United States)

2004-12-19

The microstructures formed upon solidification are strongly influenced by the imposed growth rates on an alloy system. Depending on the characteristics of the solidification process, a wide range of growth rates is accessible. The prevailing solidification mechanisms, and thus the final microstructure of the alloy, are governed by these imposed growth rates. At the high rate extreme, for instance, one can have access to novel microstructures that are unattainable at low growth rates. While the low growth rates can be utilized for the study of the intrinsic growth behavior of a certain phase growing from the melt. Although the length scales associated with certain processes, such as capillarity, and the diffusion of heat and solute, are different at low and high rate extremes, the phenomena that govern the selection of a certain microstructural length scale or a growth mode are the same. Consequently, one can analyze the solidification phenomena at both high and low rates by using the same governing principles. In this study, we examined the microstructural control at both low and high extremes. For the high rate extreme, the formation of crystalline products and factors that control the microstructure during rapid solidification by free-jet melt spinning are examined in Fe-Si-B system. Particular attention was given to the behavior of the melt pool at different quench-wheel speeds. Since the solidification process takes place within the melt-pool that forms on the rotating quench-wheel, we examined the influence of melt-pool dynamics on nucleation and growth of crystalline solidification products and glass formation. High-speed imaging of the melt-pool, analysis of ribbon microstructure, and measurement of ribbon geometry and surface character all indicate upper and lower limits for melt-spinning rates for which nucleation can be avoided, and fully amorphous ribbons can be achieved. Comparison of the relevant time scales reveals that surface-controlled melt

CO2-Philic polymer membrane with extremely high separation performance

KAUST Repository

Yave, Wilfredo

2010-01-12

Polymeric membranes are attractive for CO2 separation and concentration from different gas streams because of their versatility and energy efficiency; they can compete with, and they may even replace, traditional absorption processes. Here we describe a simple and powerful method for developing nanostructured and CO2-philic polymer membranes for CO2 separation. A poly(ethylene oxide)-poly(butylene terephthalate) multiblock copolymer is used as membrane material. Smart additives such as polyethylene glycol dibutyl ether are incorporated as spacers or fillers for producing nanostructured materials. The addition of these specific additives produces CO2-philic membranes and increases the CO2 permeability (750 barrer) up to five-fold without the loss of selectivity. The membranes present outstanding performance for CO2 separation, and the measured CO2 flux is extremely high ( > 2 m3 m -2 h-1 bar-1) with selectivity over H2 and N2 of 10 and 40, respectively, making them attractive for CO 2 capture. © 2009 American Chemical Society.

CO2-Philic polymer membrane with extremely high separation performance

KAUST Repository

Yave, Wilfredo; Car, Anja; Funari, S.; Nunes, Suzana Pereira; Peinemann, Klaus-Viktor

2010-01-01

Polymeric membranes are attractive for CO2 separation and concentration from different gas streams because of their versatility and energy efficiency; they can compete with, and they may even replace, traditional absorption processes. Here we describe a simple and powerful method for developing nanostructured and CO2-philic polymer membranes for CO2 separation. A poly(ethylene oxide)-poly(butylene terephthalate) multiblock copolymer is used as membrane material. Smart additives such as polyethylene glycol dibutyl ether are incorporated as spacers or fillers for producing nanostructured materials. The addition of these specific additives produces CO2-philic membranes and increases the CO2 permeability (750 barrer) up to five-fold without the loss of selectivity. The membranes present outstanding performance for CO2 separation, and the measured CO2 flux is extremely high ( > 2 m3 m -2 h-1 bar-1) with selectivity over H2 and N2 of 10 and 40, respectively, making them attractive for CO 2 capture. © 2009 American Chemical Society.

Extreme Transients in the High Energy Universe

Science.gov (United States)

Kouveliotou, Chryssa

2013-01-01

The High Energy Universe is rich in diverse populations of objects spanning the entire cosmological (time)scale, from our own present-day Milky Way to the re-ionization epoch. Several of these are associated with extreme conditions irreproducible in laboratories on Earth. Their study thus sheds light on the behavior of matter under extreme conditions, such as super-strong magnetic fields (in excess of 10^14 G), high gravitational potentials (e.g., Super Massive Black Holes), very energetic collimated explosions resulting in relativistic jet flows (e.g., Gamma Ray Bursts, exceeding 10^53 ergs). In the last thirty years, my work has been mostly focused on two apparently different but potentially linked populations of such transients: magnetars (highly magnetized neutron stars) and Gamma Ray Bursts (strongly beamed emission from relativistic jets), two populations that constitute unique astrophysical laboratories, while also giving us the tools to probe matter conditions in the Universe to redshifts beyond z=10, when the first stars and galaxies were assembled. I did not make this journey alone I have either led or participated in several international collaborations studying these phenomena in multi-wavelength observations; solitary perfection is not sufficient anymore in the world of High Energy Astrophysics. I will describe this journey, present crucial observational breakthroughs, discuss key results and muse on the future of this field.

Wave-mixing with high-order harmonics in extreme ultraviolet region

International Nuclear Information System (INIS)

Dao, Lap Van; Dinh, Khuong Ba; Le, Hoang Vu; Gaffney, Naylyn; Hannaford, Peter

2015-01-01

We report studies of the wave-mixing process in the extreme ultraviolet region with two near-infrared driving and controlling pulses with incommensurate frequencies (at 1400 nm and 800 nm). A non-collinear scheme for the two beams is used in order to spatially separate and to characterise the properties of the high-order wave-mixing field. We show that the extreme ultraviolet frequency mixing can be treated by perturbative, very high-order nonlinear optics; the modification of the wave-packet of the free electron needs to be considered in this process

High resolution modelling of extreme precipitation events in urban areas

Science.gov (United States)

Siemerink, Martijn; Volp, Nicolette; Schuurmans, Wytze; Deckers, Dave

2015-04-01

The present day society needs to adjust to the effects of climate change. More extreme weather conditions are expected, which can lead to longer periods of drought, but also to more extreme precipitation events. Urban water systems are not designed for such extreme events. Most sewer systems are not able to drain the excessive storm water, causing urban flooding. This leads to high economic damage. In order to take appropriate measures against extreme urban storms, detailed knowledge about the behaviour of the urban water system above and below the streets is required. To investigate the behaviour of urban water systems during extreme precipitation events new assessment tools are necessary. These tools should provide a detailed and integral description of the flow in the full domain of overland runoff, sewer flow, surface water flow and groundwater flow. We developed a new assessment tool, called 3Di, which provides detailed insight in the urban water system. This tool is based on a new numerical methodology that can accurately deal with the interaction between overland runoff, sewer flow and surface water flow. A one-dimensional model for the sewer system and open channel flow is fully coupled to a two-dimensional depth-averaged model that simulates the overland flow. The tool uses a subgrid-based approach in order to take high resolution information of the sewer system and of the terrain into account [1, 2]. The combination of using the high resolution information and the subgrid based approach results in an accurate and efficient modelling tool. It is now possible to simulate entire urban water systems using extreme high resolution (0.5m x 0.5m) terrain data in combination with a detailed sewer and surface water network representation. The new tool has been tested in several Dutch cities, such as Rotterdam, Amsterdam and The Hague. We will present the results of an extreme precipitation event in the city of Schiedam (The Netherlands). This city deals with

High power klystrons for efficient reliable high power amplifiers

Science.gov (United States)

Levin, M.

1980-11-01

This report covers the design of reliable high efficiency, high power klystrons which may be used in both existing and proposed troposcatter radio systems. High Power (10 kW) klystron designs were generated in C-band (4.4 GHz to 5.0 GHz), S-band (2.5 GHz to 2.7 GHz), and L-band or UHF frequencies (755 MHz to 985 MHz). The tubes were designed for power supply compatibility and use with a vapor/liquid phase heat exchanger. Four (4) S-band tubes were developed in the course of this program along with two (2) matching focusing solenoids and two (2) heat exchangers. These tubes use five (5) tuners with counters which are attached to the focusing solenoids. A reliability mathematical model of the tube and heat exchanger system was also generated.

Extreme meteorological conditions

International Nuclear Information System (INIS)

Altinger de Schwarzkopf, M.L.

1983-01-01

Different meteorological variables which may reach significant extreme values, such as the windspeed and, in particular, its occurrence through tornadoes and hurricanes that necesarily incide and wich must be taken into account at the time of nuclear power plants' installation, are analyzed. For this kind of study, it is necessary to determine the basic phenomenum of design. Two criteria are applied to define the basic values of design for extreme meteorological variables. The first one determines the expected extreme value: it is obtained from analyzing the recurence of the phenomenum in a convened period of time, wich may be generally of 50 years. The second one determines the extreme value of low probability, taking into account the nuclear power plant's operating life -f.ex. 25 years- and considering, during said lapse, the occurrence probabilities of extreme meteorological phenomena. The values may be determined either by the deterministic method, which is based on the acknowledgement of the fundamental physical characteristics of the phenomena or by the probabilistic method, that aims to the analysis of historical statistical data. Brief comments are made on the subject in relation to the Argentine Republic area. (R.J.S.) [es

Extremely high-power-density atmospheric-pressure thermal plasma jet generated by the nitrogen-boosted effect

Science.gov (United States)

Hanafusa, Hiroaki; Nakashima, Ryosuke; Nakano, Wataru; Higashi, Seiichiro

2018-06-01

In this study, the effect of N2 addition to an atmospheric-pressure Ar thermal plasma jet (TPJ) on ultrarapid heating was investigated. With increasing N2 flow rate, a boost of arc voltage to ∼36 V was observed, which significantly improved heating characteristics. As a result, a drastic power density increase from 10 to 125 kW/cm2 was achieved with the addition of 2.0 L/min N2 to 3.0 L/min Ar. The results of optical emission analysis and heating characteristics evaluation implied that dissociation and recombination of N2 molecules and the high thermal transport property of nitrogen gas play important roles in the increase in TPJ power density. Furthermore, we obtained TPJ extension with N2 addition that reached 300 mm, and it showed spatial enhancement of heat transport characteristics.

Fiscal 2000 achievement report. Development of prompt-effect technology for innovative energy environment (Research and development of extremely low power consuming LSI for information terminal); 2000 nendo sokkoteki kakushinteki energy kankyo gijutsu kaihatsu seika hokokusho. Gokuteidenryoku joho tanmatsuyo LSI no kenkyu kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

With the advancement of information technologies, multimedia information terminals such as handyphone systems and mobile computers are increasing in number and improving in quality, sharply increasing power consumption in this domain. So as to suppress the power consumption, efforts are exerted to develop technologies for information terminal LSI (large-scale integration) substrates consuming extremely low power and still capable of high-speed operation. Studied are a device technology of SOI (silicon on insulator) to realize a remarkable reduction in power consumption and enable high-speed operation and a circuit technology of the multi-threshold CMOS (complementary metal-oxide semiconductor) advantageous to the achievement of low-voltage high-speed operation. In concrete terms, the efforts center about an extremely thin film SOI device of the full depletion type higher in transistor driving capability, lower in load capacity, and smaller in surface area than those currently in use, and aim to put such an SOI device on an optimized multi-threshold CMOS circuit for the establishment of techniques toward the embodiment of an LSI substrate consuming extremely low electric power. (NEDO)

An analysis of the radiation field characteristics for extremity dose assessment during maintenance periods at nuclear power plants in Korea

International Nuclear Information System (INIS)

Kim, H. G.; Kong, T. Y.

2012-01-01

Workers who maintain the water chambers of steam generators during maintenance periods in nuclear power plants (NPPs) have a higher likelihood of high radiation exposure, even if they are exposed for a short period of time. In particular, it is expected that the hands of workers would receive the highest radiation exposure as a consequence of hand contact with radioactive materials. In this study, a characteristic analysis of inhomogeneous radiation fields for contact operations was conducted using thermoluminescent dosemeters for the whole body and extremities during maintenance periods at Korean NPPs. It was observed that inhomogeneous radiation fields for contact operations at NPPs were dominated by high-energy photons. (authors)

Probabilistic residual life assessment of high temperature pipings in nuclear power plants against creep fatigue damage: final report

International Nuclear Information System (INIS)

Gupta, Sanjay

2014-02-01

Residual life assessment of components of nuclear power plants is essential for their operational safety, reliability and financial viability. The high risks involved in the event of failures in nuclear power plants have led to the development of design philosophies that incorporate extreme conservatism in design. The implications of such conservatism in design leads to more frequent maintenance operations than necessary

Early warnings of extreme winds using the ECMWF Extreme Forecast Index

OpenAIRE

Petroliagis, Thomas I.; Pinson, Pierre

2014-01-01

The European FP7 SafeWind Project aims at developing research towards a European vision of wind power forecasting, which requires advanced meteorological support concerning extreme wind events. This study is focused mainly on early warnings of extreme winds in the early medium-range. Three synoptic stations (airports) of North Germany (Bremen, Hamburg and Hannover) were considered for the construction of time series of daily maximum wind speeds. All daily wind extremes were found to be linked...

Is Extremely High Life Satisfaction during Adolescence Advantageous?

Science.gov (United States)

Suldo, Shannon M.; Huebner, E. Scott

2006-01-01

This study examined whether extremely high life satisfaction was associated with adaptive functioning or maladaptive functioning. Six hundred ninety-eight secondary level students completed the Students' Life Satisfaction Scale [Huebner, 1991a, School Psychology International, 12, pp. 231-240], Youth Self-Report of the Child Behavior Checklist…

Relativistic electron-atom scattering in an extremely powerful laser field: Relevance of spin effects

International Nuclear Information System (INIS)

Panek, P.; Kaminski, J.Z.; Ehlotzky, F.

2002-01-01

We reconsider the relativistic scattering of electrons by an atom, being approximated by a static potential, in an extremely powerful electromagnetic plane wave of frequency ω and linear polarization ε. Since to a first order of approximation spin effects can be neglected, we first describe the scattered electron by the Gordon solution of the Klein-Gordon equation. Then we investigate the same scattering process by including the spin effects, using for the electron the Volkov solution of the Dirac equation. For sufficiently energetic electrons, the first-order Born approximation can be employed to represent the corresponding scattering matrix element. We compare the results of the differential cross sections of induced and inverse bremsstrahlung, evaluated from both approximations, for various parameter values and angular configurations and we find that in most cases the spin effects are marginal, even at very high laser power. On the other hand, we recover the various asymmetries in the angular distributions of the scattered electrons and their respective energies due to the laser-induced drift motion of the electrons in the direction of propagation of the radiation field, thus confirming the findings of our previous work [Phys. Rev. A 59, 2105 (1999); Laser Physics 10, 163 (2000)

Development of highly reliable power and communication system for essential instruments under severe accidents in NPP

Energy Technology Data Exchange (ETDEWEB)

Choi, Bo Hwan; Jang, Gi Chan; Shin, Sung Min; Kang, Hyun Gook; Rim, Chun Taek [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Lee, Soo Ill [I and C Group, Korea Hydro and Nuclear Power Co., Ltd, Central Research Institute, Daejeon (Korea, Republic of)

2016-10-15

This article proposes a highly reliable power and communication system that guarantees the protection of essential instruments in a nuclear power plant under a severe accident. Both power and communication lines are established with not only conventional wired channels, but also the proposed wireless channels for emergency reserve. An inductive power transfer system is selected due to its robust power transfer characteristics under high temperature, high pressure, and highly humid environments with a large amount of scattered debris after a severe accident. A thermal insulation box and a glass-fiber reinforced plastic box are proposed to protect the essential instruments, including vulnerable electronic circuits, from extremely high temperatures of up to 627 .deg. C and pressure of up to 5 bar. The proposed wireless power and communication system is experimentally verified by an inductive power transfer system prototype having a dipole coil structure and prototype Zigbee modules over a 7-m distance, where both the thermal insulation box and the glass-fiber reinforced plastic box are fabricated and tested using a high-temperature chamber. Moreover, an experiment on the effects of a high radiation environment on various electronic devices is conducted based on the radiation test having a maximum accumulated dose of 27 Mrad.

Development of Highly Reliable Power and Communication System for Essential Instruments Under Severe Accidents in NPP

Directory of Open Access Journals (Sweden)

Bo Hwan Choi

2016-10-01

Full Text Available This article proposes a highly reliable power and communication system that guarantees the protection of essential instruments in a nuclear power plant under a severe accident. Both power and communication lines are established with not only conventional wired channels, but also the proposed wireless channels for emergency reserve. An inductive power transfer system is selected due to its robust power transfer characteristics under high temperature, high pressure, and highly humid environments with a large amount of scattered debris after a severe accident. A thermal insulation box and a glass-fiber reinforced plastic box are proposed to protect the essential instruments, including vulnerable electronic circuits, from extremely high temperatures of up to 627°C and pressure of up to 5 bar. The proposed wireless power and communication system is experimentally verified by an inductive power transfer system prototype having a dipole coil structure and prototype Zigbee modules over a 7-m distance, where both the thermal insulation box and the glass-fiber reinforced plastic box are fabricated and tested using a high-temperature chamber. Moreover, an experiment on the effects of a high radiation environment on various electronic devices is conducted based on the radiation test having a maximum accumulated dose of 27 Mrad.

Development of highly reliable power and communication system for essential instruments under severe accidents in NPP

International Nuclear Information System (INIS)

Choi, Bo Hwan; Jang, Gi Chan; Shin, Sung Min; Kang, Hyun Gook; Rim, Chun Taek; Lee, Soo Ill

2016-01-01

This article proposes a highly reliable power and communication system that guarantees the protection of essential instruments in a nuclear power plant under a severe accident. Both power and communication lines are established with not only conventional wired channels, but also the proposed wireless channels for emergency reserve. An inductive power transfer system is selected due to its robust power transfer characteristics under high temperature, high pressure, and highly humid environments with a large amount of scattered debris after a severe accident. A thermal insulation box and a glass-fiber reinforced plastic box are proposed to protect the essential instruments, including vulnerable electronic circuits, from extremely high temperatures of up to 627 .deg. C and pressure of up to 5 bar. The proposed wireless power and communication system is experimentally verified by an inductive power transfer system prototype having a dipole coil structure and prototype Zigbee modules over a 7-m distance, where both the thermal insulation box and the glass-fiber reinforced plastic box are fabricated and tested using a high-temperature chamber. Moreover, an experiment on the effects of a high radiation environment on various electronic devices is conducted based on the radiation test having a maximum accumulated dose of 27 Mrad

High-power klystrons

Science.gov (United States)

Siambis, John G.; True, Richard B.; Symons, R. S.

1994-05-01

Novel emerging applications in advanced linear collider accelerators, ionospheric and atmospheric sensing and modification and a wide spectrum of industrial processing applications, have resulted in microwave tube requirements that call for further development of high power klystrons in the range from S-band to X-band. In the present paper we review recent progress in high power klystron development and discuss some of the issues and scaling laws for successful design. We also discuss recent progress in electron guns with potential grading electrodes for high voltage with short and long pulse operation via computer simulations obtained from the code DEMEOS, as well as preliminary experimental results. We present designs for high power beam collectors.

Switching power converters medium and high power

CERN Document Server

Neacsu, Dorin O

2013-01-01

An examination of all of the multidisciplinary aspects of medium- and high-power converter systems, including basic power electronics, digital control and hardware, sensors, analog preprocessing of signals, protection devices and fault management, and pulse-width-modulation (PWM) algorithms, Switching Power Converters: Medium and High Power, Second Edition discusses the actual use of industrial technology and its related subassemblies and components, covering facets of implementation otherwise overlooked by theoretical textbooks. The updated Second Edition contains many new figures, as well as

Nonlinear wave-mixing processes in the extreme ultraviolet

International Nuclear Information System (INIS)

Misoguti, L.; Christov, I. P.; Backus, S.; Murnane, M. M.; Kapteyn, H. C.

2005-01-01

We present data from two-color high-order harmonic generation in a hollow waveguide, that suggest the presence of a nonlinear-optical frequency conversion process driven by extreme ultraviolet light. By combining the fundamental and second harmonic of an 800 nm laser in a hollow-core fiber, with varying relative polarizations, and by observing the pressure and power scaling of the various harmonic orders, we show that the data are consistent with a picture where we drive the process of high-harmonic generation, which in turn drives four-wave frequency mixing processes in the extreme EUV. This work promises a method for extending nonlinear optics into the extreme ultraviolet region of the spectrum using an approach that has not previously been considered, and has compelling implications for generating tunable light at short wavelengths

Solar Weather Ice Monitoring Station (SWIMS). A low cost, extreme/harsh environment, solar powered, autonomous sensor data gathering and transmission system

Science.gov (United States)

Chetty, S.; Field, L. A.

2013-12-01

The Arctic ocean's continuing decrease of summer-time ice is related to rapidly diminishing multi-year ice due to the effects of climate change. Ice911 Research aims to develop environmentally respectful materials that when deployed will increase the albedo, enhancing the formation and/preservation of multi-year ice. Small scale deployments using various materials have been done in Canada, California's Sierra Nevada Mountains and a pond in Minnesota to test the albedo performance and environmental characteristics of these materials. SWIMS is a sophisticated autonomous sensor system being developed to measure the albedo, weather, water temperature and other environmental parameters. The system (SWIMS) employs low cost, high accuracy/precision sensors, high resolution cameras, and an extreme environment command and data handling computer system using satellite and terrestrial wireless communication. The entire system is solar powered with redundant battery backup on a floating buoy platform engineered for low temperature (-40C) and high wind conditions. The system also incorporates tilt sensors, sonar based ice thickness sensors and a weather station. To keep the costs low, each SWIMS unit measures incoming and reflected radiation from the four quadrants around the buoy. This allows data from four sets of sensors, cameras, weather station, water temperature probe to be collected and transmitted by a single on-board solar powered computer. This presentation covers the technical, logistical and cost challenges in designing, developing and deploying these stations in remote, extreme environments. Image captured by camera #3 of setting sun on the SWIMS station One of the images captured by SWIMS Camera #4

Entropy method combined with extreme learning machine method for the short-term photovoltaic power generation forecasting

International Nuclear Information System (INIS)

Tang, Pingzhou; Chen, Di; Hou, Yushuo

2016-01-01

As the world’s energy problem becomes more severe day by day, photovoltaic power generation has opened a new door for us with no doubt. It will provide an effective solution for this severe energy problem and meet human’s needs for energy if we can apply photovoltaic power generation in real life, Similar to wind power generation, photovoltaic power generation is uncertain. Therefore, the forecast of photovoltaic power generation is very crucial. In this paper, entropy method and extreme learning machine (ELM) method were combined to forecast a short-term photovoltaic power generation. First, entropy method is used to process initial data, train the network through the data after unification, and then forecast electricity generation. Finally, the data results obtained through the entropy method with ELM were compared with that generated through generalized regression neural network (GRNN) and radial basis function neural network (RBF) method. We found that entropy method combining with ELM method possesses higher accuracy and the calculation is faster.

EMA beamline at SIRIUS: extreme condition X-ray methods of analysis

International Nuclear Information System (INIS)

Souza Neto, Narcizo

2016-01-01

Full text: The EMA beamline (Extreme condition X-ray Methods of Analysis) is one of the hard x-ray undulator beamlines within the first phase of the new synchrotron source in Brazil (Sirius project). This beamline is thought to make a difference where a high brilliance (high flux of up to 2 x 10 14 photons/sec with beam size down to 0.5 x 0.5 μm 2 ) is essential, which is the case for extreme pressures that require small focus and time-resolved that require high photon flux. With that in mind we propose the beamline to have two experimental hutches to cover most of the extreme condition techniques today employed at synchrotron laboratories worldwide. These two stations are thought to provide the general infrastructure for magnets and lasers experiments, which may evolve as new scientific problems appear. In addition to the hutches, support laboratories will be strongly linked and supportive to the experiments at the beamline, covering high pressure instrumentations using diamond anvil cells and pump-and-probe requirements for ultrafast and high power lasers. Along these lines, we will describe the following techniques covered at this beamline: magnetic spectroscopy (XMCD) and scattering (XRMS) under high pressure and very low temperature in order to fully probe both ferromagnetic and antiferromagnetic materials and the dependence with pressure; extreme pressure and temperature XRD and XAS experiments using very small diamond culet anvils and high power lasers. (author)

EMA beamline at SIRIUS: extreme condition X-ray methods of analysis

Energy Technology Data Exchange (ETDEWEB)

Souza Neto, Narcizo, E-mail: narcizo.souza@lnls.br [Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, SP (Brazil)

2016-07-01

Full text: The EMA beamline (Extreme condition X-ray Methods of Analysis) is one of the hard x-ray undulator beamlines within the first phase of the new synchrotron source in Brazil (Sirius project). This beamline is thought to make a difference where a high brilliance (high flux of up to 2 x 10{sup 14} photons/sec with beam size down to 0.5 x 0.5 μm{sup 2}) is essential, which is the case for extreme pressures that require small focus and time-resolved that require high photon flux. With that in mind we propose the beamline to have two experimental hutches to cover most of the extreme condition techniques today employed at synchrotron laboratories worldwide. These two stations are thought to provide the general infrastructure for magnets and lasers experiments, which may evolve as new scientific problems appear. In addition to the hutches, support laboratories will be strongly linked and supportive to the experiments at the beamline, covering high pressure instrumentations using diamond anvil cells and pump-and-probe requirements for ultrafast and high power lasers. Along these lines, we will describe the following techniques covered at this beamline: magnetic spectroscopy (XMCD) and scattering (XRMS) under high pressure and very low temperature in order to fully probe both ferromagnetic and antiferromagnetic materials and the dependence with pressure; extreme pressure and temperature XRD and XAS experiments using very small diamond culet anvils and high power lasers. (author)

High temperature heat exchanger application in power engineering and energy-technological processes

International Nuclear Information System (INIS)

Shpilrain, E.E.

1986-01-01

The possibilities for intensification of various processes in metallurgy and chemical technology, the prospects for enhancing power plant efficiency are often linked with temperature increase of reagents, heat carriers and working fluids. In some cases elevated temperatures give the opportunity to use new and principally different technologies, enhance capacities of power production units and technological apparatuses, improve their economical performance. The variety of problems where high temperature heat exchangers are or can be used are extremely wide. It is therefore impossible to overview all of them in one lecture. Therefore the author tries to consider only some examples which are typical and gives an impression of what kind of problems arise in these cases

Low Power Design with High-Level Power Estimation and Power-Aware Synthesis

CERN Document Server

Ahuja, Sumit; Shukla, Sandeep Kumar

2012-01-01

Low-power ASIC/FPGA based designs are important due to the need for extended battery life, reduced form factor, and lower packaging and cooling costs for electronic devices. These products require fast turnaround time because of the increasing demand for handheld electronic devices such as cell-phones, PDAs and high performance machines for data centers. To achieve short time to market, design flows must facilitate a much shortened time-to-product requirement. High-level modeling, architectural exploration and direct synthesis of design from high level description enable this design process. This book presents novel research techniques, algorithms,methodologies and experimental results for high level power estimation and power aware high-level synthesis. Readers will learn to apply such techniques to enable design flows resulting in shorter time to market and successful low power ASIC/FPGA design. Integrates power estimation and reduction for high level synthesis, with low-power, high-level design; Shows spec...

High-resolution Sonographic Measurements of Lower Extremity Bursae in Chinese Healthy Young Men

Directory of Open Access Journals (Sweden)

Yong-Yan Gao

2016-01-01

Conclusions: Using HR-US imaging, we were able to analyze lower extremity bursae with high detection rates in healthy young men. The normal ranges of lower extremity bursa dimensions in healthy young men measured by HR-US in this study could be used as reference values for evaluation of bursa abnormalities in the lower extremity.

A low power high speed radiation hard serializer for High Energy Physics experiments

CERN Document Server

AUTHOR|(CDS)2080243; Marchioro, Alessandro; Ottavi, Marco

This Ph.D. thesis focuses on the development and the characterization of novel solutions for electronic systems for high-speed data transmission in extremely high radio-active environment (e.g. high energy physics application). The text proposes two alternative full-custom solutions for a fundamental enabling block for a lowpower serial data transmission system, the serializer. This block will find place in a future transceiver conceived for the future upgraded phase of the Large Hadron Collider, or LHC, at CERN. The first solution proposed, called “triple module redundancy”, is based on hardware redundancy, a well-known solution, to obtain protection against the temporary malfunctioning induced by radiation. In the second case a new architecture, called “code protected”, is proposed. This architecture takes advantage of the error correction code present in the data word to obtain radiation robustness on data and some parts of the control logic and to further reduce the power consumption. A test chip ...

Extreme earthquake response of nuclear power plants isolated using sliding bearings

Energy Technology Data Exchange (ETDEWEB)

Kumar, Manish, E-mail: mkumar@iitgn.ac.in [Department of Civil Engineering, Indian Institute of Technology Gandhinagar, Gandhinagar 382355 (India); Whittaker, Andrew S.; Constantinou, Michael C. [Department of Civil, Structural and Environmental Engineering, University at Buffalo, Buffalo, NY 14260 (United States)

2017-05-15

Highlights: • Response-history analysis of a nuclear power plant (NPP) isolated using sliding bearings. • Two models of the NPP, five friction models and four seismic hazard levels considered. • Isolation system displacement can be obtained using a macro NPP model subjected to only horizontal ground motions. • Temperature dependence of friction should be considered in isolation-system displacement calculations. • The effect of friction model on floor spectral ordinates is rather small, especially near the basemat. - Abstract: Horizontal seismic isolation is a viable approach to mitigate risk to structures, systems and components (SSCs) in nuclear power plants (NPPs) under extreme ground shaking. This paper presents a study on an NPP seismically isolated using single concave Friction Pendulum™ (FP) bearings subjected to ground motions representing seismic hazard at two US sites: Diablo Canyon and Vogtle. Two models of the NPP, five models to describe friction at the sliding surface of the FP bearings, and four levels of ground shaking are considered for response-history analysis, which provide insight into the influence of 1) the required level of detail of an NPP model, 2) the vertical component of ground motion on response of isolated NPPs, and 3) the pressure-, temperature- and/or velocity-dependencies of the coefficient of friction, on the response of an isolated NPP. The isolation-system displacement of an NPP can be estimated using a macro model subjected to only the two orthogonal horizontal components of ground motion. The variation of the coefficient of friction with temperature at the sliding surface during earthquake shaking should be accounted for in the calculation of isolation-system displacements, particularly when the shaking intensity is high; pressure and velocity dependencies are not important. In-structure floor spectra should be computed using a detailed three-dimensional model of an isolated NPP subjected to all three components of

Extremely high thermal conductivity anisotropy of double-walled carbon nanotubes

Directory of Open Access Journals (Sweden)

Zhaoji Ma

2017-06-01

Full Text Available Based on molecular dynamics simulations, we reveal that double-walled carbon nanotubes can possess an extremely high anisotropy ratio of radial to axial thermal conductivities. The mechanism is basically the same as that for the high thermal conductivity anisotropy of graphene layers - the in-plane strong sp2 bonds lead to a very high intralayer thermal conductivity while the weak van der Waals interactions to a very low interlayer thermal conductivity. However, different from flat graphene layers, the tubular structures of carbon nanotubes result in a diameter dependent thermal conductivity. The smaller the diameter, the larger the axial thermal conductivity but the smaller the radial thermal conductivity. As a result, a DWCNT with a small diameter may have an anisotropy ratio of thermal conductivity significantly higher than that for graphene layers. The extremely high thermal conductivity anisotropy allows DWCNTs to be a promising candidate for thermal management materials.

A new VME based high voltage power supply for large experiments

Energy Technology Data Exchange (ETDEWEB)

Ahn, S.C.; Angstadt, R.D.; Droege, T.F.; Johnson, M.E.; MacKinnon, B.A.; McNulty, S.E.; Shea, M.F.; Thompson, R.N.; Watson, M.M. (Fermi National Accelerator Lab., Batavia, IL (United States)); Franzini, P. (Columbia Univ., New York, NY (United States)); Jones, A.A. (Superconducting Super Collider Lab., Dallas, TX (United States)); Lopez, M.L. (La Plata Univ. Nacional (Argentina)); Wimpenny, S.J.; Yang, M.J

1991-11-01

A new VME based high voltage power supply has been developed for the D{O} experiment at Fermilab. There are three types of supplies delivering up to {plus minus}5.6 kV at 1.0 mA or +2.0 kV at 3.0 mA with a set accuracy of 1.5 V and extremely low voltage ripples. Complete computer control has allowed many special features to be developed for the supply, including user-defined control land monitor groups, variable ramp rates, and advanced histogram and graphic functions. 3 refs.

A new VME based high voltage power supply for large experiments

International Nuclear Information System (INIS)

Ahn, S.C.; Angstadt, R.D.; Droege, T.F.; Johnson, M.E.; MacKinnon, B.A.; McNulty, S.E.; Shea, M.F.; Thompson, R.N.; Watson, M.M.; Franzini, P.; Jones, A.A.; Lopez, M.L.; Wimpenny, S.J.; Yang, M.J.

1991-11-01

A new VME based high voltage power supply has been developed for the D OE experiment at Fermilab. There are three types of supplies delivering up to ±5.6 kV at 1.0 mA or +2.0 kV at 3.0 mA with a set accuracy of 1.5 V and extremely low voltage ripples. Complete computer control has allowed many special features to be developed for the supply, including user-defined control land monitor groups, variable ramp rates, and advanced histogram and graphic functions. 3 refs

High power communication satellites power systems study

International Nuclear Information System (INIS)

Josloff, A.T.; Peterson, J.R.

1994-01-01

This paper discusses a DOE-funded study to evaluate the commercial attractiveness of high power communication satellites and assesses the attributes of both conventional photovoltaic and reactor power systems. This study brings together a preeminent US Industry/Russian team to cooperate on the role of high power communication satellites in the rapidly expanding communications revolution. These high power satellites play a vital role in assuring availability of universally accessible, wide bandwidth communications, for high definition TV, super computer networks and other services. Satellites are ideally suited to provide the wide bandwidths and data rates required and are unique in the ability to provide services directly to the users. As new or relocated markets arise, satellites offer a flexibility that conventional distribution services cannot match, and it is no longer necessary to be near population centers to take advantage of the telecommunication revolution. The geopolitical implications of these substantially enhanced communications capabilities will be significant

Extreme Consumption Drinking Gaming and Prepartying among High School Students

Science.gov (United States)

Tomaso, Cara C.; Zamboanga, Byron L.; Haas, Amie L.; Kenney, Shannon R.; Ham, Lindsay S.; Borsari, Brian

2016-01-01

Drinking games and prepartying (i.e., drinking before going to a social gathering/event) have emerged as high-risk drinking behaviors in high school students. The present study examines the current prepartying behaviors of high school students who report current participation in extreme-consumption games (e.g., chugging) with those who do not.…

CSTI High Capacity Power

International Nuclear Information System (INIS)

Winter, J.M.

1989-01-01

The SP-100 program was established in 1983 by DOD, DOE, and NASA as a joint program to develop the technology necessary for space nuclear power systems for military and civil application. During FY-86 and 87, the NASA SP-100 Advanced Technology Program was devised to maintain the momentum of promising technology advancement efforts started during Phase 1 of SP-100 and to strengthen, in key areas, the chances for successful development and growth capability of space nuclear reactor power systems for future space applications. In FY-88, the Advanced Technology Program was incorporated into NASA's new Civil Space Technology Initiative (CSTI). The CSTI Program was established to provide the foundation for technology development in automation and robotics, information, propulsion, and power. The CSTI High Capacity Power Program builds on the technology efforts of the SP-100 program, incorporates the previous NASA SP-100 Advanced Technology project, and provides a bridge to NASA Project Pathfinder. The elements of CSTI High Capacity Power development include Conversion Systems, Thermal Management, Power Management, System Diagnostics, and Environmental Interactions. Technology advancement in all areas, including materials, is required to assure the high reliability and 7 to 10 year lifetime demanded for future space nuclear power systems. The overall program will develop and demonstrate the technology base required to provide a wide range of modular power systems as well as allowing mission independence from solar and orbital attitude requirements. Several recent advancements in CSTI High Capacity power development will be discussed

Design of an L-band normally conducting RF gun cavity for high peak and average RF power

Energy Technology Data Exchange (ETDEWEB)

Paramonov, V., E-mail: paramono@inr.ru [Institute for Nuclear Research of Russian Academy of Sciences, 60-th October Anniversary prospect 7a, 117312 Moscow (Russian Federation); Philipp, S. [Deutsches Elektronen-Synchrotron DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Rybakov, I.; Skassyrskaya, A. [Institute for Nuclear Research of Russian Academy of Sciences, 60-th October Anniversary prospect 7a, 117312 Moscow (Russian Federation); Stephan, F. [Deutsches Elektronen-Synchrotron DESY, Platanenallee 6, D-15738 Zeuthen (Germany)

2017-05-11

To provide high quality electron bunches for linear accelerators used in free electron lasers and particle colliders, RF gun cavities operate with extreme electric fields, resulting in a high pulsed RF power. The main L-band superconducting linacs of such facilities also require a long RF pulse length, resulting in a high average dissipated RF power in the gun cavity. The newly developed cavity based on the proven advantages of the existing DESY RF gun cavities, underwent significant changes. The shape of the cells is optimized to reduce the maximal surface electric field and RF loss power. Furthermore, the cavity is equipped with an RF probe to measure the field amplitude and phase. The elaborated cooling circuit design results in a lower temperature rise on the cavity RF surface and permits higher dissipated RF power. The paper presents the main solutions and results of the cavity design.

Extreme external events in the design and assessment of nuclear power plants

International Nuclear Information System (INIS)

2003-03-01

The analysis of feedback experience from the operation of nuclear power plants (NPPs) in the past 20 years shows few cases of degradation of the plant safety initiated by external events. However, when these have occurred, the consequences have been serious, involving challenges to the defence in depth of the plant. Part of the problem involves the definition of the design basis parameters for some scenarios and differences among regulators on the methods for the protection of operational NPPs in relation to external events. This results in different engineering practices in Member States for the siting and design of NPPs. In the framework of the present revision of the IAEA safety standards on siting and design of NPPs, many initiatives have been implemented by the IAEA in recent years aimed at a systematic analysis of engineering practices in Member States. The most recent event in this connection was a Technical Committee Meeting (TCM) on Structural Safety of NPPs in Relation to Extreme External Loads, organized with the specific objective of evaluating the state of the art of NPP design in relation to external events. Such an analysis provided a technical background for the development of a common technical basis for an integrated approach in site evaluation, design and operation in relation to extreme external events. The scope included new and existing plants, as they are required to meet the same general safety principles, in spite of their peculiarities. The objective of this publication is to provide a technical background to drive regulators, plant owners and designers in the definition of a consistent strategy in selected safety issues on site evaluation, design and operation in relation to extreme external events. This publication is also of support to the IAEA in the development of safety standards since many Safety Guides dealing with related topics are under periodic review. Four major tasks were identified to comply with these general objectives

Associations Between Measures of Balance and Lower-Extremity Muscle Strength/Power in Healthy Individuals Across the Lifespan: A Systematic Review and Meta-Analysis.

Science.gov (United States)

Muehlbauer, Thomas; Gollhofer, Albert; Granacher, Urs

2015-12-01

It has frequently been reported that balance and lower-extremity muscle strength/power are associated with sports-related and everyday activities. Knowledge about the relationship between balance, strength, and power are important for the identification of at-risk individuals because deficits in these neuromuscular components are associated with an increased risk of sustaining injuries and falls. In addition, this knowledge is of high relevance for the development of specifically tailored health and skill-related exercise programs. The objectives of this systematic literature review and meta-analysis were to characterize and, if possible, quantify associations between variables of balance and lower-extremity muscle strength/power in healthy individuals across the lifespan. A computerized systematic literature search was performed in the electronic databases PubMed, Web of Science, and SPORTDiscus up to March 2015 to capture all relevant articles. A systematic approach was used to evaluate the 996 articles identified for initial review. Studies were included only if they investigated healthy individuals aged ≥6 years and tested at least one measure of static steady-state balance (e.g., center of pressure [CoP] displacement during one-legged stance), dynamic steady-state balance (e.g., gait speed), proactive balance (e.g., distance in the functional-reach-test), or reactive balance (e.g., CoP displacement during perturbed one-legged stance), and one measure of maximal strength (e.g., maximum voluntary contraction), explosive force (e.g., rate of force development), or muscle power (e.g., jump height). In total, 37 studies met the inclusionary criteria for review. The included studies were coded for the following criteria: age (i.e., children: 6-12 years, adolescents: 13-18 years, young adults: 19-44 years, middle-aged adults: 45-64 years, old adults: ≥65 years), sex (i.e., female, male), and test modality/outcome (i.e., test for the assessment of balance

High to ultra-high power electrical energy storage.

Science.gov (United States)

Sherrill, Stefanie A; Banerjee, Parag; Rubloff, Gary W; Lee, Sang Bok

2011-12-14

High power electrical energy storage systems are becoming critical devices for advanced energy storage technology. This is true in part due to their high rate capabilities and moderate energy densities which allow them to capture power efficiently from evanescent, renewable energy sources. High power systems include both electrochemical capacitors and electrostatic capacitors. These devices have fast charging and discharging rates, supplying energy within seconds or less. Recent research has focused on increasing power and energy density of the devices using advanced materials and novel architectural design. An increase in understanding of structure-property relationships in nanomaterials and interfaces and the ability to control nanostructures precisely has led to an immense improvement in the performance characteristics of these devices. In this review, we discuss the recent advances for both electrochemical and electrostatic capacitors as high power electrical energy storage systems, and propose directions and challenges for the future. We asses the opportunities in nanostructure-based high power electrical energy storage devices and include electrochemical and electrostatic capacitors for their potential to open the door to a new regime of power energy.

Extreme-Environment Silicon-Carbide (SiC) Wireless Sensor Suite

Science.gov (United States)

Yang, Jie

2015-01-01

Phase II objectives: Develop an integrated silicon-carbide wireless sensor suite capable of in situ measurements of critical characteristics of NTP engine; Compose silicon-carbide wireless sensor suite of: Extreme-environment sensors center, Dedicated high-temperature (450 deg C) silicon-carbide electronics that provide power and signal conditioning capabilities as well as radio frequency modulation and wireless data transmission capabilities center, An onboard energy harvesting system as a power source.

Core-shell N-doped active carbon fiber@graphene composites for aqueous symmetric supercapacitors with high-energy and high-power density

Science.gov (United States)

Xie, Qinxing; Bao, Rongrong; Xie, Chao; Zheng, Anran; Wu, Shihua; Zhang, Yufeng; Zhang, Renwei; Zhao, Peng

2016-06-01

Graphene wrapped nitrogen-doped active carbon fibers (ACF@GR) of a core-shell structure were successfully prepared by a simple dip-coating method using natural silk as template. Compared to pure silk active carbon, the as-prepared ACF@GR composites exhibit high specific surface area in a range of 1628-2035 m2 g-1, as well as superior energy storage capability, an extremely high single-electrode capacitance of 552.8 F g-1 was achieved at a current density of 0.1 A g-1 in 6 M KOH aqueous electrolyte. The assembled aqueous symmetric supercapacitors are capable of deliver both high energy density and high power density, for instance, 17.1 Wh kg-1 at a power density of 50.0 W kg-1, and 12.2 Wh kg-1 at 4.7 kW kg-1 with a retention rate of 71.3% for ACF@GR1-based supercapacitor.

Antenna diagnostics for power flow in extreme near-field of a standard gain horn

DEFF Research Database (Denmark)

Popa, Paula Irina; Breinbjerg, Olav

2016-01-01

The plane wave spectrum of an aperture antenna can be calculated from a complex measurement of the radiated near- or far-field and it facilitates antenna diagnostics for the extreme near-field of the antenna. While antenna diagnostics often concerns the magnitude of the co-polar field, the plane...... wave spectrum actually allows for determination of both magnitude and phase of all three components of the electric as well as the magnetic field - and thus also the Poynting vector. In this work we focus on the Poynting vector and thus the power flow in the extreme near-field; as an example we employ...... that these oscillations are not merely a “Gibbs-like” phenomenon due to the availability of only the visible region of the plane wave spectrum and they are not caused by multiple reflections between the horn and the near-field probe - but resulted from the interference between the direct field and the edge...

High average power solid state laser power conditioning system

International Nuclear Information System (INIS)

Steinkraus, R.F.

1987-01-01

The power conditioning system for the High Average Power Laser program at Lawrence Livermore National Laboratory (LLNL) is described. The system has been operational for two years. It is high voltage, high power, fault protected, and solid state. The power conditioning system drives flashlamps that pump solid state lasers. Flashlamps are driven by silicon control rectifier (SCR) switched, resonant charged, (LC) discharge pulse forming networks (PFNs). The system uses fiber optics for control and diagnostics. Energy and thermal diagnostics are monitored by computers

A hybrid fuzzy logic and extreme learning machine for improving efficiency of circulating water systems in power generation plant

Science.gov (United States)

Aziz, Nur Liyana Afiqah Abdul; Siah Yap, Keem; Afif Bunyamin, Muhammad

2013-06-01

This paper presents a new approach of the fault detection for improving efficiency of circulating water system (CWS) in a power generation plant using a hybrid Fuzzy Logic System (FLS) and Extreme Learning Machine (ELM) neural network. The FLS is a mathematical tool for calculating the uncertainties where precision and significance are applied in the real world. It is based on natural language which has the ability of "computing the word". The ELM is an extremely fast learning algorithm for neural network that can completed the training cycle in a very short time. By combining the FLS and ELM, new hybrid model, i.e., FLS-ELM is developed. The applicability of this proposed hybrid model is validated in fault detection in CWS which may help to improve overall efficiency of power generation plant, hence, consuming less natural recourses and producing less pollutions.

A hybrid fuzzy logic and extreme learning machine for improving efficiency of circulating water systems in power generation plant

International Nuclear Information System (INIS)

Aziz, Nur Liyana Afiqah Abdul; Yap, Keem Siah; Bunyamin, Muhammad Afif

2013-01-01

This paper presents a new approach of the fault detection for improving efficiency of circulating water system (CWS) in a power generation plant using a hybrid Fuzzy Logic System (FLS) and Extreme Learning Machine (ELM) neural network. The FLS is a mathematical tool for calculating the uncertainties where precision and significance are applied in the real world. It is based on natural language which has the ability of c omputing the word . The ELM is an extremely fast learning algorithm for neural network that can completed the training cycle in a very short time. By combining the FLS and ELM, new hybrid model, i.e., FLS-ELM is developed. The applicability of this proposed hybrid model is validated in fault detection in CWS which may help to improve overall efficiency of power generation plant, hence, consuming less natural recourses and producing less pollutions.

High-resolution stochastic generation of extreme rainfall intensity for urban drainage modelling applications

Science.gov (United States)

Peleg, Nadav; Blumensaat, Frank; Molnar, Peter; Fatichi, Simone; Burlando, Paolo

2016-04-01

Urban drainage response is highly dependent on the spatial and temporal structure of rainfall. Therefore, measuring and simulating rainfall at a high spatial and temporal resolution is a fundamental step to fully assess urban drainage system reliability and related uncertainties. This is even more relevant when considering extreme rainfall events. However, the current space-time rainfall models have limitations in capturing extreme rainfall intensity statistics for short durations. Here, we use the STREAP (Space-Time Realizations of Areal Precipitation) model, which is a novel stochastic rainfall generator for simulating high-resolution rainfall fields that preserve the spatio-temporal structure of rainfall and its statistical characteristics. The model enables a generation of rain fields at 102 m and minute scales in a fast and computer-efficient way matching the requirements for hydrological analysis of urban drainage systems. The STREAP model was applied successfully in the past to generate high-resolution extreme rainfall intensities over a small domain. A sub-catchment in the city of Luzern (Switzerland) was chosen as a case study to: (i) evaluate the ability of STREAP to disaggregate extreme rainfall intensities for urban drainage applications; (ii) assessing the role of stochastic climate variability of rainfall in flow response and (iii) evaluate the degree of non-linearity between extreme rainfall intensity and system response (i.e. flow) for a small urban catchment. The channel flow at the catchment outlet is simulated by means of a calibrated hydrodynamic sewer model.

Extreme-scale Algorithms and Solver Resilience

Energy Technology Data Exchange (ETDEWEB)

Dongarra, Jack [Univ. of Tennessee, Knoxville, TN (United States)

2016-12-10

A widening gap exists between the peak performance of high-performance computers and the performance achieved by complex applications running on these platforms. Over the next decade, extreme-scale systems will present major new challenges to algorithm development that could amplify this mismatch in such a way that it prevents the productive use of future DOE Leadership computers due to the following; Extreme levels of parallelism due to multicore processors; An increase in system fault rates requiring algorithms to be resilient beyond just checkpoint/restart; Complex memory hierarchies and costly data movement in both energy and performance; Heterogeneous system architectures (mixing CPUs, GPUs, etc.); and Conflicting goals of performance, resilience, and power requirements.

Asthma in Patients Climbing to High and Extreme Altitudes in the Tibetan Everest Region

NARCIS (Netherlands)

Huismans, Henrike K.; Douma, W. Rob; Kerstjens, Huib A. M.; Renkema, Tineke E. J.

Objectives: The aim of this study was to investigate the behavior of asthma in patients traveling to high and extreme altitudes. Methods: Twenty-four Dutch patients with mild asthma did a trekking at high and extreme altitudes (up to 6410 m = 21030 ft) in the Tibetan Everest region. Asthma symptoms,

High-intensity power-resolved radiation imaging of an operational nuclear reactor.

Science.gov (United States)

Beaumont, Jonathan S; Mellor, Matthew P; Villa, Mario; Joyce, Malcolm J

2015-10-09

Knowledge of the neutron distribution in a nuclear reactor is necessary to ensure the safe and efficient burnup of reactor fuel. Currently these measurements are performed by in-core systems in what are extremely hostile environments and in most reactor accident scenarios it is likely that these systems would be damaged. Here we present a compact and portable radiation imaging system with the ability to image high-intensity fast-neutron and gamma-ray fields simultaneously. This system has been deployed to image radiation fields emitted during the operation of a TRIGA test reactor allowing a spatial visualization of the internal reactor conditions to be obtained. The imaged flux in each case is found to scale linearly with reactor power indicating that this method may be used for power-resolved reactor monitoring and for the assay of ongoing nuclear criticalities in damaged nuclear reactors.

Microbial Fuel Cells under Extreme Salinity

Science.gov (United States)

Monzon del Olmo, Oihane

I developed a Microbial Fuel Cell (MFC) that unprecedentedly works (i.e., produces electricity) under extreme salinity (≈ 100 g/L NaCl). Many industries, such as oil and gas extraction, generate hypersaline wastewaters with high organic strength, accounting for about 5% of worldwide generated effluents, which represent a major challenge for pollution control and resource recovery. This study assesses the potential for microbial fuel cells (MFCs) to treat such wastewaters and generate electricity under extreme saline conditions. Specifically, the focus is on the feasibility to treat hypersaline wastewater generated by the emerging unconventional oil and gas industry (hydraulic fracturing) and so, with mean salinity of 100 g/L NaCl (3-fold higher than sea water). The success of this novel technology strongly depends on finding a competent and resilient microbial community that can degrade the waste under extreme saline conditions and be able to use the anode as their terminal electron acceptor (exoelectrogenic capability). I demonstrated that MFCs can produce electricity at extremely high salinity (up to 250 g/l NaCl) with a power production of 71mW/m2. Pyrosequencing analysis of the anode population showed the predominance of Halanaerobium spp. (85%), which has been found in shale formations and oil reservoirs. Promoting Quorum sensing (QS, cell to cell communication between bacteria to control gene expression) was used as strategy to increase the attachment of bacteria to the anode and thus improve the MFC performance. Results show that the power output can be bolstered by adding 100nM of quinolone signal with an increase in power density of 30%, for the first time showing QS in Halanaerobium extremophiles. To make this technology closer to market applications, experiments with real wastewaters were also carried out. A sample of produced wastewater from Barnet Shale, Texas (86 g/L NaCl) produced electricity when fed in an MFC, leading to my discovery of another

Solar Probe Plus MAG Sensor Thermal Design for Low Heater Power and Extreme Thermal Environment

Science.gov (United States)

Choi, Michael K.

2015-01-01

The heater power available for the Solar Probe Plus FIELDS MAG sensor is less than half of the heritage value for other missions. Nominally the MAG sensors are in the spacecraft's umbra. In the worst hot case, approximately 200 spacecraft communication downlinks, up to 10 hours each, are required at 0.7 AU. These downlinks require the spacecraft to slew 45 deg. about the Y-axis, exposing the MAG sensors and boom to sunlight. This paper presents the thermal design to meet the MAG sensor thermal requirements in the extreme thermal environment and with low heater power. A thermal balance test on the MAG sensor engineering model has verified the thermal design and correlated the thermal model for flight temperature predictions.

Impacts of Extreme Events on Human Health. Chapter 4

Science.gov (United States)

Bell, Jesse E.; Herring, Stephanie C.; Jantarasami, Lesley; Adrianopoli, Carl; Benedict, Kaitlin; Conlon, Kathryn; Escobar, Vanessa; Hess, Jeremy; Luvall, Jeffrey; Garcia-Pando, Carlos Perez;

High power communication satellites power systems study

Science.gov (United States)

Josloff, Allan T.; Peterson, Jerry R.

1995-01-01

This paper discusses a planned study to evaluate the commercial attractiveness of high power communication satellites and assesses the attributes of both conventional photovoltaic and reactor power systems. These high power satellites can play a vital role in assuring availability of universally accessible, wide bandwidth communications, for high definition TV, super computer networks and other services. Satellites are ideally suited to provide the wide bandwidths and data rates required and are unique in the ability to provide services directly to the users. As new or relocated markets arise, satellites offer a flexibility that conventional distribution services cannot match, and it is no longer necessary to be near population centers to take advantage of the telecommunication revolution. The geopolitical implications of these substantially enhanced communications capabilities can be significant.

Production processes at extremely high energies

CERN Document Server

Gastmans, R; Wu, Tai Tsun

2013-01-01

The production processes are identified that contribute to the rise of the total cross section in proton-proton scattering at extremely high energies, s->~. At such energies, the scattering can be described by a black disk (completely absorptive) with a radius expanding logarithmically with energy surrounded by a gray fringe (partially absorptive). For the leading term of (lns)^2 in the increasing total cross section, the gray fringe is neglected, and geometrical optics is generalized to production processes. It is known that half of the rise in the total cross section is due to elastic scattering. The other half is found to originate from the production of jets with relatively small momenta in the center-of-mass system.

High power microwaves

CERN Document Server

Benford, James; Schamiloglu, Edl

2016-01-01

Following in the footsteps of its popular predecessors, High Power Microwaves, Third Edition continues to provide a wide-angle, integrated view of the field of high power microwaves (HPMs). This third edition includes significant updates in every chapter as well as a new chapter on beamless systems that covers nonlinear transmission lines. Written by an experimentalist, a theorist, and an applied theorist, respectively, the book offers complementary perspectives on different source types. The authors address: * How HPM relates historically and technically to the conventional microwave field * The possible applications for HPM and the key criteria that HPM devices have to meet in order to be applied * How high power sources work, including their performance capabilities and limitations * The broad fundamental issues to be addressed in the future for a wide variety of source types The book is accessible to several audiences. Researchers currently in the field can widen their understanding of HPM. Present or pot...

Choice of optimal working fluid for binary power plants at extremely low temperature brine

Science.gov (United States)

Tomarov, G. V.; Shipkov, A. A.; Sorokina, E. V.

2016-12-01

The geothermal energy development problems based on using binary power plants utilizing lowpotential geothermal resources are considered. It is shown that one of the possible ways of increasing the efficiency of heat utilization of geothermal brine in a wide temperature range is the use of multistage power systems with series-connected binary power plants based on incremental primary energy conversion. Some practically significant results of design-analytical investigations of physicochemical properties of various organic substances and their influence on the main parameters of the flowsheet and the technical and operational characteristics of heat-mechanical and heat-exchange equipment for binary power plant operating on extremely-low temperature geothermal brine (70°C) are presented. The calculation results of geothermal brine specific flow rate, capacity (net), and other operation characteristics of binary power plants with the capacity of 2.5 MW at using various organic substances are a practical interest. It is shown that the working fluid selection significantly influences on the parameters of the flowsheet and the operational characteristics of the binary power plant, and the problem of selection of working fluid is in the search for compromise based on the priorities in the field of efficiency, safety, and ecology criteria of a binary power plant. It is proposed in the investigations on the working fluid selection of the binary plant to use the plotting method of multiaxis complex diagrams of relative parameters and characteristic of binary power plants. Some examples of plotting and analyzing these diagrams intended to choose the working fluid provided that the efficiency of geothermal brine is taken as main priority.

High gain requirements and high field Tokamak experiments

International Nuclear Information System (INIS)

Cohn, D.R.

1994-01-01

Operation at sufficiently high gain (ratio of fusion power to external heating power) is a fundamental requirement for tokamak power reactors. For typical reactor concepts, the gain is greater than 25. Self-heating from alpha particles in deuterium-tritium plasmas can greatly reduce ητ/temperature requirements for high gain. A range of high gain operating conditions is possible with different values of alpha-particle efficiency (fraction of alpha-particle power that actually heats the plasma) and with different ratios of self heating to external heating. At one extreme, there is ignited operation, where all of the required plasma heating is provided by alpha particles and the alpha-particle efficiency is 100%. At the other extreme, there is the case of no heating contribution from alpha particles. ητ/temperature requirements for high gain are determined as a function of alpha-particle heating efficiency. Possibilities for high gain experiments in deuterium-tritium, deuterium, and hydrogen plasmas are discussed

Comparative outcome of bomb explosion injuries versus high-powered gunshot injuries of the upper extremity in a civilian setting.

Science.gov (United States)

Luria, Shai; Rivkin, Gurion; Avitzour, Malka; Liebergall, Meir; Mintz, Yoav; Mosheiff, Ram

2013-03-01

Explosion injuries to the upper extremity have specific clinical characteristics that differ from injuries due to other mechanisms. To evaluate the upper extremity injury pattern of attacks on civilian targets, comparing bomb explosion injuries to gunshot injuries and their functional recovery using standard outcome measures. Of 157 patients admitted to the hospital between 2000 and 2004, 72 (46%) sustained explosion injuries and 85 (54%) gunshot injuries. The trauma registry files were reviewed and the patients completed the DASH Questionnaire (Disabilities of Arm, Shoulder and Hand) and SF-12 (Short Form-12) after a minimum period of 1 year. Of the 157 patients, 72 (46%) had blast injuries and 85 (54%) had shooting injuries. The blast casualties had higher Injury Severity Scores (47% vs. 22% with a score of > 16, P = 0.02) and higher percent of patients treated in intensive care units (47% vs. 28%, P = 0.02). Although the Abbreviated Injury Scale score of the upper extremity injury was similar in the two groups, the blast casualties were found to have more bilateral and complex soft tissue injuries and were treated surgically more often. No difference was found in the SF-12 or DASH scores between the groups at follow up. The casualties with upper extremity blast injuries were more severely injured and sustained more bilateral and complex soft tissue injuries to the upper extremity. However, the rating of the local injury to the isolated limb is similar, as was the subjective functional recovery.

Stable, Extreme Temperature, High Radiation, Compact. Low Power Clock Oscillator for Space, Geothermal, Down-Hole & other High Reliability Applications, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Efficient and stable clock signal generation requirements at extreme temperatures (-180C to +450C)and radiation (>250 Krad TID) are not met with the current...

Extremely Randomized Machine Learning Methods for Compound Activity Prediction

Directory of Open Access Journals (Sweden)

Wojciech M. Czarnecki

2015-11-01

Full Text Available Speed, a relatively low requirement for computational resources and high effectiveness of the evaluation of the bioactivity of compounds have caused a rapid growth of interest in the application of machine learning methods to virtual screening tasks. However, due to the growth of the amount of data also in cheminformatics and related fields, the aim of research has shifted not only towards the development of algorithms of high predictive power but also towards the simplification of previously existing methods to obtain results more quickly. In the study, we tested two approaches belonging to the group of so-called ‘extremely randomized methods’—Extreme Entropy Machine and Extremely Randomized Trees—for their ability to properly identify compounds that have activity towards particular protein targets. These methods were compared with their ‘non-extreme’ competitors, i.e., Support Vector Machine and Random Forest. The extreme approaches were not only found out to improve the efficiency of the classification of bioactive compounds, but they were also proved to be less computationally complex, requiring fewer steps to perform an optimization procedure.

Extreme waves at Filyos, southern Black Sea

Directory of Open Access Journals (Sweden)

E. Bilyay

2011-03-01

Full Text Available A wave measurement project was carried out for a new port planned in Filyos, in the Western Black Sea region of Turkey. The measurement at a depth of 12.5 m lasted for a period of two years and 7949 records were obtained. During the analysis, it was noticed that there were 209 records in which H/H_s ratio was higher than 2.0. These higher waves in a record are called extreme waves in this study. Although the purpose of wave measurement is not to investigate extreme waves, it is believed that studying these unexpected waves could be interesting. Therefore, detailed statistical and spectral analyses on the extreme waves were done for the records. The analyses results show that the distribution of surface profiles of the records containing extreme waves deviates from Gaussian distribution with the negative skewness changing between –0.01 and –0.4 and with the high kurtosis in the range of 3.1–4.2. Although the probability of occurrence of the extreme waves is over-predicted by the Rayleigh distribution, a higher ratio of H_s/η_rms indicates that the wave height distribution can be represented by Rayleigh. The average value of the slope of the frequency spectrum at the high frequency range is proportional to f^–9 which is much steeper than the typical wind-wave frequency power law, f^{–4, –5}. The directional spreading is measured with the parameter S_max and it is in the range of 5–70 for the extreme wave records. The wave and current interaction was also investigated and it was found that in most cases, extreme waves occur when the wave and the current are almost aligned. Furthermore, it is observed that extreme waves appear within a group of high waves.

Design, fabrication, and characterization of high-efficiency extreme ultraviolet diffusers

Energy Technology Data Exchange (ETDEWEB)

Naulleau, Patrick P.; Liddle, J. Alexander; Salmassi, Farhad; Anderson, Erik H.; Gullikson, Eric M.

2004-02-19

As the development of extreme ultraviolet (EUV) lithography progresses, interest grows in the extension of traditional optical components to the EUV regime. The strong absorption of EUV by most materials and its extremely short wavelength, however, makes it very difficult to implement many components that are commonplace in the longer wavelength regimes. One such example is the diffuser often implemented with ordinary ground glass in the visible light regime. Here we demonstrate the fabrication of reflective EUV diffusers with high efficiency within a controllable bandwidth. Using these techniques we have fabricated diffusers with efficiencies exceeding 10% within a moderate angular single-sided bandwidth of approximately 0.06 radians.

High Power High Efficiency Diode Laser Stack for Processing

Science.gov (United States)

Gu, Yuanyuan; Lu, Hui; Fu, Yueming; Cui, Yan

2018-03-01

High-power diode lasers based on GaAs semiconductor bars are well established as reliable and highly efficient laser sources. As diode laser is simple in structure, small size, longer life expectancy with the advantages of low prices, it is widely used in the industry processing, such as heat treating, welding, hardening, cladding and so on. Respectively, diode laser could make it possible to establish the practical application because of rectangular beam patterns which are suitable to make fine bead with less power. At this power level, it can have many important applications, such as surgery, welding of polymers, soldering, coatings and surface treatment of metals. But there are some applications, which require much higher power and brightness, e.g. hardening, key hole welding, cutting and metal welding. In addition, High power diode lasers in the military field also have important applications. So all developed countries have attached great importance to high-power diode laser system and its applications. This is mainly due their low performance. In this paper we will introduce the structure and the principle of the high power diode stack.

INLA goes extreme: Bayesian tail regression for the estimation of high spatio-temporal quantiles

KAUST Repository

Opitz, Thomas

2018-05-25

This work is motivated by the challenge organized for the 10th International Conference on Extreme-Value Analysis (EVA2017) to predict daily precipitation quantiles at the 99.8% level for each month at observed and unobserved locations. Our approach is based on a Bayesian generalized additive modeling framework that is designed to estimate complex trends in marginal extremes over space and time. First, we estimate a high non-stationary threshold using a gamma distribution for precipitation intensities that incorporates spatial and temporal random effects. Then, we use the Bernoulli and generalized Pareto (GP) distributions to model the rate and size of threshold exceedances, respectively, which we also assume to vary in space and time. The latent random effects are modeled additively using Gaussian process priors, which provide high flexibility and interpretability. We develop a penalized complexity (PC) prior specification for the tail index that shrinks the GP model towards the exponential distribution, thus preventing unrealistically heavy tails. Fast and accurate estimation of the posterior distributions is performed thanks to the integrated nested Laplace approximation (INLA). We illustrate this methodology by modeling the daily precipitation data provided by the EVA2017 challenge, which consist of observations from 40 stations in the Netherlands recorded during the period 1972–2016. Capitalizing on INLA’s fast computational capacity and powerful distributed computing resources, we conduct an extensive cross-validation study to select the model parameters that govern the smoothness of trends. Our results clearly outperform simple benchmarks and are comparable to the best-scoring approaches of the other teams.

Early warnings of extreme winds using the ECMWF Extreme Forecast Index

DEFF Research Database (Denmark)

Petroliagis, Thomas I.; Pinson, Pierre

2014-01-01

The European FP7 SafeWind Project aims at developing research towards a European vision of wind power forecasting, which requires advanced meteorological support concerning extreme wind events. This study is focused mainly on early warnings of extreme winds in the early medium-range. Three synoptic...... regimes. Overall, it becomes clear that the first indications of an extreme wind event might come from the ECMWF deterministic and/or probabilistic components capturing very intense weather systems (possible windstorms) in the medium term. For early warnings, all available EPS Extreme Forecast Index (EFI......) formulations were used, by linking daily maximum wind speeds to EFI values for different forecast horizons. From all possible EFI schemes deployed for issuing early warnings, the highest skill was found for the Gust Factor formulation (EFI-10FGI). Using EFI-10FGI, the corresponding 99% threshold could provide...

An effective secondary decomposition approach for wind power forecasting using extreme learning machine trained by crisscross optimization

International Nuclear Information System (INIS)

Yin, Hao; Dong, Zhen; Chen, Yunlong; Ge, Jiafei; Lai, Loi Lei; Vaccaro, Alfredo; Meng, Anbo

2017-01-01

Highlights: • A secondary decomposition approach is applied in the data pre-processing. • The empirical mode decomposition is used to decompose the original time series. • IMF1 continues to be decomposed by applying wavelet packet decomposition. • Crisscross optimization algorithm is applied to train extreme learning machine. • The proposed SHD-CSO-ELM outperforms other pervious methods in the literature. - Abstract: Large-scale integration of wind energy into electric grid is restricted by its inherent intermittence and volatility. So the increased utilization of wind power necessitates its accurate prediction. The contribution of this study is to develop a new hybrid forecasting model for the short-term wind power prediction by using a secondary hybrid decomposition approach. In the data pre-processing phase, the empirical mode decomposition is used to decompose the original time series into several intrinsic mode functions (IMFs). A unique feature is that the generated IMF1 continues to be decomposed into appropriate and detailed components by applying wavelet packet decomposition. In the training phase, all the transformed sub-series are forecasted with extreme learning machine trained by our recently developed crisscross optimization algorithm (CSO). The final predicted values are obtained from aggregation. The results show that: (a) The performance of empirical mode decomposition can be significantly improved with its IMF1 decomposed by wavelet packet decomposition. (b) The CSO algorithm has satisfactory performance in addressing the premature convergence problem when applied to optimize extreme learning machine. (c) The proposed approach has great advantage over other previous hybrid models in terms of prediction accuracy.

The Formation of a Power Multi-Pulse Extreme Ultraviolet Radiation in the Pulse Plasma Diode of Low Pressure

Directory of Open Access Journals (Sweden)

Ievgeniia V. Borgun

2013-01-01

Full Text Available In this paper results are presented on experimental studies of the temporal characteristics of spike extreme ultraviolet (EUV radiation in the spectral range of 12.2 ÷ 15.8 nm from the anode region of high-current (I = 40 kA pulsed discharges in tin vapor. It is observed that the intense multi-spike radiation in this range arises at an inductive stage of the discharge. It has been shown that the radiation spikes correlate with the sharp increase of active resistance and of pumped power, due to plasma heating by an electron beam, formed in the double layer of charged particles. It has been observed that for large number of spikes the conversion efficiency of pumped energy into radiationat double layer formation is essentially higher in comparison with collisional heating.

High power CW linac in PNC

International Nuclear Information System (INIS)

Toyama, S.; Wang, Y.L.; Emoto, T.

1994-01-01

Power Reactor and Nuclear Fuel Development Corporation (PNC) is developing a high power electron linac for various applications. The electron beam is accelerated in CW operation to get maximum beam current of 100 mA and energy of 10 MeV. Crucial components such as a high power L-band klystron and a high power traveling wave resonant ring (TWRR) accelerator guides were designed and manufactured and their performance were examined. These design and results from the recent high power RF tests were described in this paper. (author)

970-nm ridge waveguide diode laser bars for high power DWBC systems

Science.gov (United States)

Wilkens, Martin; Erbert, Götz; Wenzel, Hans; Knigge, Andrea; Crump, Paul; Maaßdorf, Andre; Fricke, Jörg; Ressel, Peter; Strohmaier, Stephan; Schmidt, Berthold; Tränkle, Günther

2018-02-01

de lasers are key components in material processing laser systems. While mostly used as pump sources for solid state or fiber lasers, direct diode laser systems using dense wavelength multiplexing have come on the market in recent years. These systems are realized with broad area lasers typically, resulting in beam quality inferior to disk or fiber lasers. We will present recent results of highly efficient ridge waveguide (RW) lasers, developed for dense-wavelength-beamcombining (DWBC) laser systems expecting beam qualities comparable to solid state laser systems and higher power conversion efficiencies (PCE). The newly developed RW lasers are based on vertical structures with an extreme double asymmetric large optical cavity. Besides a low vertical divergence these structures are suitable for RW-lasers with (10 μm) broad ridges, emitting in a single mode with a good beam quality. The large stripe width enables a lateral divergence below 10° (95 % power content) and a high PCE by a comparably low series resistance. We present results of single emitters and small test arrays under different external feedback conditions. Single emitters can be tuned from 950 nm to 975 nm and reach 1 W optical power with more than 55 % PCE and a beam quality of M2 < 2 over the full wavelength range. The spectral width is below 30 pm FWHM. 5 emitter arrays were stabilized using the same setup. Up to now we reached 3 W optical power, limited by power supply, with 5 narrow spectral lines.

Powering the High-Luminosity Triplets

Science.gov (United States)

Ballarino, A.; Burnet, J. P.

The powering of the magnets in the LHC High-Luminosity Triplets requires production and transfer of more than 150 kA of DC current. High precision power converters will be adopted, and novel High Temperature Superconducting (HTS) current leads and MgB2 based transfer lines will provide the electrical link between the power converters and the magnets. This chapter gives an overview of the systems conceived in the framework of the LHC High-Luminosity upgrade for feeding the superconducting magnet circuits. The focus is on requirements, challenges and novel developments.

Undersampling power-law size distributions: effect on the assessment of extreme natural hazards

Science.gov (United States)

Geist, Eric L.; Parsons, Thomas E.

2014-01-01

The effect of undersampling on estimating the size of extreme natural hazards from historical data is examined. Tests using synthetic catalogs indicate that the tail of an empirical size distribution sampled from a pure Pareto probability distribution can range from having one-to-several unusually large events to appearing depleted, relative to the parent distribution. Both of these effects are artifacts caused by limited catalog length. It is more difficult to diagnose the artificially depleted empirical distributions, since one expects that a pure Pareto distribution is physically limited in some way. Using maximum likelihood methods and the method of moments, we estimate the power-law exponent and the corner size parameter of tapered Pareto distributions for several natural hazard examples: tsunamis, floods, and earthquakes. Each of these examples has varying catalog lengths and measurement thresholds, relative to the largest event sizes. In many cases where there are only several orders of magnitude between the measurement threshold and the largest events, joint two-parameter estimation techniques are necessary to account for estimation dependence between the power-law scaling exponent and the corner size parameter. Results indicate that whereas the corner size parameter of a tapered Pareto distribution can be estimated, its upper confidence bound cannot be determined and the estimate itself is often unstable with time. Correspondingly, one cannot statistically reject a pure Pareto null hypothesis using natural hazard catalog data. Although physical limits to the hazard source size and by attenuation mechanisms from source to site constrain the maximum hazard size, historical data alone often cannot reliably determine the corner size parameter. Probabilistic assessments incorporating theoretical constraints on source size and propagation effects are preferred over deterministic assessments of extreme natural hazards based on historic data.

Aging characteristics of blue InGaN micro-light emitting diodes at an extremely high current density of 3.5 kA cm−2

International Nuclear Information System (INIS)

Tian, Pengfei; Liu, Ran; Althumali, Ahmad; Gu, Erdan; Watson, Ian M; Dawson, Martin D

2016-01-01

The aging characteristics of blue InGaN micro-light emitting diodes (micro-LEDs) with different sizes have been studied at an extremely high current density 3.5 kA cm −2 for emerging micro-LED applications including visible light communication (VLC), micro-LED pumped organic lasers and optogenetics. The light output power of micro-LEDs first increases and then decreases due to the competition of Mg activation in p-GaN layer and defect generation in the active region. The smaller micro-LEDs show less light output power degradation compared with larger micro-LEDs, which is attributed to the lower junction temperature of smaller micro-LEDs. It is found that the high current density without additional junction temperature cannot induce significant micro-LED degradation at room temperature but the combination of the high current density and high junction temperature leads to strong degradation. Furthermore, the cluster LEDs, composed of a micro-LED array, have been developed with both high light output power and less light output degradation for micro-LED applications in solid state lighting and VLC. (paper)

Extreme field limits in the interaction of laser light with ultrarelativistic electrons

Energy Technology Data Exchange (ETDEWEB)

Bulanov, S. V.; Esirkepov, T. Zh.; Hayashi, Y.; Kando, M.; Kiriyama, H.; Koga, J.; Kondo, K.; Kotaki, H.; Pirozhkov, A.; Bulanov, S. S.; Zhidkov, A.; Chen, P.; Neely, D.; Kato, Y.; Narozhny, N. B.; Korn, G. [Kansai Photon Science Institute, JAEA, Kizugawa, Kyoto 619-0215 (Japan); University of California, Berkeley, CA 94720 (United States); Osaka University, Osaka 565-0871 (Japan); National Taiwan University, Taipei 10617, Taiwan (China); Central Laser Facility, STFC, Rutherford Appleton Laboratory, Didcot OX11 0QX (United Kingdom); Graduate School for the Creation of New Photonics Industries, Hamamatsu, Shizuoka 431-1202 (Japan); Moscow Engineering Physics Institute (State University), Moscow 115409 (Russian Federation); Max-Planck-Institut fuer Quantenoptik, Garching 85748 (Germany) and ELI Beamline Facility, Institute of Physics, CAS, Prague 18221 (Czech Republic)

2012-07-11

The critical electric field of quantum electrodynamics is so strong that it produces electron-positron pairs from vacuum, converting the energy of light into matter. This field has become feasible through the construction of extremely high power lasers or/and with the sophisticated use of nonlinear processes in relativistic plasmas. A feasibility of the experiments on the collision of laser light and high intensity electromagnetic pulses, generated by relativistic flying mirrors, with relativistic electrons for the studying of extreme field limits in the nonlinear interaction of electromagnetic waves is discussed.

Review of Power System Stability with High Wind Power Penetration

DEFF Research Database (Denmark)

Hu, Rui; Hu, Weihao; Chen, Zhe

2015-01-01

analyzing methods and stability improvement approaches. With increasing wind power penetration, system balancing and the reduced inertia may cause a big threaten for stable operation of power systems. To mitigate or eliminate the wind impacts for high wind penetration systems, although the practical......This paper presents an overview of researches on power system stability with high wind power penetration including analyzing methods and improvement approaches. Power system stability issues can be classified diversely according to different considerations. Each classified issue has special...... and reliable choices currently are the strong outside connections or sufficient reserve capacity constructions, many novel theories and approaches are invented to investigate the stability issues, looking forward to an extra-high penetration or totally renewable resource based power systems. These analyzing...

Extremal edges: a powerful cue to depth perception and figure-ground organization.

Science.gov (United States)

Palmer, Stephen E; Ghose, Tandra

2008-01-01

Extremal edges (EEs) are projections of viewpoint-specific horizons of self-occlusion on smooth convex surfaces. An ecological analysis of viewpoint constraints suggests that an EE surface is likely to be closer to the observer than the non-EE surface on the other side of the edge. In two experiments, one using shading gradients and the other using texture gradients, we demonstrated that EEs operate as strong cues to relative depth perception and figure-ground organization. Image regions with an EE along the shared border were overwhelmingly perceived as closer than either flat or equally convex surfaces without an EE along that border. A further demonstration suggests that EEs are more powerful than classical figure-ground cues, including even the joint effects of small size, convexity, and surroundedness.

Autonomously managed high power systems

International Nuclear Information System (INIS)

Weeks, D.J.; Bechtel, R.T.

1985-01-01

The need for autonomous power management capabilities will increase as the power levels of spacecraft increase into the multi-100 kW range. The quantity of labor intensive ground and crew support consumed by the 9 kW Skylab cannot be afforded in support of a 75-300 kW Space Station or high power earth orbital and interplanetary spacecraft. Marshall Space Flight Center is managing a program to develop necessary technologies for high power system autonomous management. To date a reference electrical power system and automation approaches have been defined. A test facility for evaluation and verification of management algorithms and hardware has been designed with the first of the three power channel capability nearing completion

ICAN: High power neutral beam generation

International Nuclear Information System (INIS)

Moustaizis, S.D.; Lalousis, P.; Perrakis, K.; Auvray, P.; Larour, J.; Ducret, J.E.; Balcou, P.

2015-01-01

During the last few years there is an increasing interest on the development of alternative high power new negative ion source for Tokamak applications. The proposed new neutral beam device presents a number of advantages with respect to: the density current, the acceleration voltage, the relative compact dimension of the negative ion source, and the coupling of a high power laser beam for photo-neutralization of the negative ion beam. Here we numerically investigate, using a multi- fluid 1-D code, the acceleration and the extraction of high power ion beam from a Magnetically Insulated Diode (MID). The diode configuration will be coupled to a high power device capable of extracting a current up to a few kA with an accelerating voltage up to MeV. An efficiency of up to 92% of the coupling of the laser beam, is required in order to obtain a high power, up to GW, neutral beam. The new high energy, high average power, high efficiency (up to 30%) ICAN fiber laser is proposed for both the plasma generation and the photo-neutralizer configuration. (authors)

Reflectance Tuning at Extreme Ultraviolet (EUV) Wavelengths with Active Multilayer Mirrors

NARCIS (Netherlands)

Bayraktar, Muharrem; Lee, Christopher James; van Goor, F.A.; Koster, Gertjan; Rijnders, Augustinus J.H.M.; Bijkerk, Frederik

2011-01-01

At extreme ultraviolet (EUV) wavelengths the refractive power of transmission type optical components is limited, therefore reflective components are used. Reflective optics (multilayer mirrors) usually consist of many bilayers and each bilayer is composed of a high and a low refractive index

Condensed Matter NMR under Extreme Conditions: Challenges and Opportunities

Science.gov (United States)

Reyes, Arneil

2006-11-01

Advances in resistive magnet and power supply technology have made available extremely high magnetic fields suitable for condensed matter broadline NMR experiments. This capability expands the available phase space for investigating a wide variety of materials using magnetic resonance; utilizing the strength of the field to expose or induce new physical phenomena resulting in better understanding of the physics. Continuous fields up to 45T in NHMFL Hybrid magnet have brought new challenges in designing NMR instrumentation. Field strengths and sample space limitations put constraints on RF pulse power, tuning range, bandwidth, and temperature control. The inclusion of other capabilities, including high pressure, optics, and sample rotation requires intricate probe design and construction, while extremely low milliKelvin temperatures are desired in order to explore energy scales where thermal fluctuations are suppressed. Optimization of these devices has been of paramount consideration in NHMFL Condensed Matter NMR user program. Science achieved at high fields, the new initiatives to develop resistively-detected NMR in 2D electron gas and similar systems, and the current new generation Series-Connected Hybrid magnets for NMR work will be discussed. The NHMFL is supported by the National Science Foundation and the State of Florida.

High average power supercontinuum sources

Indian Academy of Sciences (India)

The physical mechanisms and basic experimental techniques for the creation of high average spectral power supercontinuum sources is briefly reviewed. We focus on the use of high-power ytterbium-doped fibre lasers as pump sources, and the use of highly nonlinear photonic crystal fibres as the nonlinear medium.

Racial Extremism in the Army

Science.gov (United States)

1998-04-01

of Deference ...................................................................................................... 46 1. The Separation of Powers Doctrine...to the military. This deference has a two-fold basis. First, the separation of powers in the U.S. Constitution gives authority to the executive (and...Why should there be judicial deference to the Army’s policy on extremism? There are two principal reasons. First, the Constitution’s separation of powers doctrine

The influence of wheelchair propulsion technique on upper extremity muscle demand: a simulation study.

Science.gov (United States)

Rankin, Jeffery W; Kwarciak, Andrew M; Richter, W Mark; Neptune, Richard R

2012-11-01

The majority of manual wheelchair users will experience upper extremity injuries or pain, in part due to the high force requirements, repetitive motion and extreme joint postures associated with wheelchair propulsion. Recent studies have identified cadence, contact angle and peak force as important factors for reducing upper extremity demand during propulsion. However, studies often make comparisons between populations (e.g., able-bodied vs. paraplegic) or do not investigate specific measures of upper extremity demand. The purpose of this study was to use a musculoskeletal model and forward dynamics simulations of wheelchair propulsion to investigate how altering cadence, peak force and contact angle influence individual muscle demand. Forward dynamics simulations of wheelchair propulsion were generated to emulate group-averaged experimental data during four conditions: 1) self-selected propulsion technique, and while 2) minimizing cadence, 3) maximizing contact angle, and 4) minimizing peak force using biofeedback. Simulations were used to determine individual muscle mechanical power and stress as measures of muscle demand. Minimizing peak force and cadence had the lowest muscle power requirements. However, minimizing peak force increased cadence and recovery power, while minimizing cadence increased average muscle stress. Maximizing contact angle increased muscle stress and had the highest muscle power requirements. Minimizing cadence appears to have the most potential for reducing muscle demand and fatigue, which could decrease upper extremity injuries and pain. However, altering any of these variables to extreme values appears to be less effective; instead small to moderate changes may better reduce overall muscle demand. Copyright © 2012 Elsevier Ltd. All rights reserved.

High Temperature, High Power Piezoelectric Composite Transducers

Science.gov (United States)

Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, StewarT.

2014-01-01

Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

A 380 V High Efficiency and High Power Density Switched-Capacitor Power Converter using Wide Band Gap Semiconductors

DEFF Research Database (Denmark)

Fan, Lin; Knott, Arnold; Jørgensen, Ivan Harald Holger

2018-01-01

. This paper presents such a high voltage low power switched-capacitor DC-DC converter with an input voltage upto 380 V (compatible with rectified European mains) and an output power experimentally validated up to 21.3 W. The wideband gap semiconductor devices of GaN switches and SiC diodes are combined...... to compose the proposed power stage. Their switching and loss characteristics are analyzed with transient waveforms and thermal images. Different isolated driving circuits are compared and a compact isolated halfbridge driving circuit is proposed. The full-load efficiencies of 98.3% and 97.6% are achieved......State-of-the-art switched-capacitor DC-DC power converters mainly focus on low voltage and/or high power applications. However, at high voltage and low power levels, new designs are anticipated to emerge and a power converter that has both high efficiency and high power density is highly desirable...

Fault analysis and strategy of high pulsed power supply for high power laser

International Nuclear Information System (INIS)

Liu Kefu; Qin Shihong; Li Jin; Pan Yuan; Yao Zonggan; Zheng Wanguo; Guo Liangfu; Zhou Peizhang; Li Yizheng; Chen Dehuai

2001-01-01

according to the requirements of driving flash-lamp, a high pulsed power supply (PPS) based on capacitors as energy storage elements is designed. The author analyzes in detail the faults of high pulsed power supply for high power laser. Such as capacitor internal short-circuit, main bus breakdown to ground, flashlamp sudden short or break. The fault current and voltage waveforms were given by circuit simulations. Based on the analysis and computation, the protection strategy with the fast fuse and ZnO was put forward, which can reduce the damage of PPS to the lower extent and provide the personnel safe and collateral property from the all threats. The preliminary experiments demonstrated that the design of the PPS can satisfy the project requirements

Lower-extremity resistance training on unstable surfaces improves proxies of muscle strength, power and balance in healthy older adults: a randomised control trial.

Science.gov (United States)

Eckardt, Nils

2016-11-24

It is well documented that both balance and resistance training have the potential to mitigate intrinsic fall risk factors in older adults. However, knowledge about the effects of simultaneously executed balance and resistance training (i.e., resistance training conducted on unstable surfaces [URT]) on lower-extremity muscle strength, power and balance in older adults is insufficient. The objective of the present study was to compare the effects of machine-based stable resistance training (M-SRT) and two types of URT, i.e., machine-based (M-URT) and free-weight URT (F-URT), on measures of lower-extremity muscle strength, power and balance in older adults. Seventy-five healthy community-dwelling older adults aged 65-80 years, were assigned to three intervention groups: M-SRT, M-URT and F-URT. Over a period of ten weeks, all participants exercised two times per week with each session lasting ~60 min. Tests included assessment of leg muscle strength (e.g., maximal isometric leg extension strength), power (e.g., chair rise test) and balance (e.g., functional reach test), carried out before and after the training period. Furthermore, maximal training load of the squat-movement was assessed during the last training week. Maximal training load of the squat-movement was significantly lower in F-URT in comparison to M-SRT and M-URT. However, lower-extremity resistance training conducted on even and uneven surfaces meaningfully improved proxies of strength, power and balance in all groups. M-URT produced the greatest improvements in leg extension strength and F-URT in the chair rise test and functional reach test. Aside from two interaction effects, overall improvements in measures of lower-extremity muscle strength, power and balance were similar across training groups. Importantly, F-URT produced similar results with considerably lower training load as compared to M-SRT and M-URT. Concluding, F-URT seems an effective and safe alternative training program to mitigate

High Power Density Power Electronic Converters for Large Wind Turbines

DEFF Research Database (Denmark)

Senturk, Osman Selcuk

. For these VSCs, high power density is required due to limited turbine nacelle space. Also, high reliability is required since maintenance cost of these remotely located wind turbines is quite high and these turbines operate under harsh operating conditions. In order to select a high power density and reliability......In large wind turbines (in MW and multi-MW ranges), which are extensively utilized in wind power plants, full-scale medium voltage (MV) multi-level (ML) voltage source converters (VSCs) are being more preferably employed nowadays for interfacing these wind turbines with electricity grids...... VSC solution for wind turbines, first, the VSC topology and the switch technology to be employed should be specified such that the highest possible power density and reliability are to be attained. Then, this qualitative approach should be complemented with the power density and reliability...

Characteristics of extreme ultraviolet emission from high-Z plasmas

International Nuclear Information System (INIS)

Ohashi, H.; Higashiguchi, T.; Suzuki, Y.; Kawasaki, M.; Suzuki, C.; Tomita, K.; Nishikino, M.; Fujioka, S.; Endo, A.; Li, B.; Otsuka, T.; Dunne, P.; O'Sullivan, G.

2016-01-01

We demonstrate the extreme ultraviolet (EUV) and soft x-ray sources in the 2 to 7 nm spectral region related to the beyond EUV (BEUV) question at 6.x nm and the water window source based on laser-produced high-Z plasmas. Resonance emission from multiply charged ions merges to produce intense unresolved transition arrays (UTAs), extending below the carbon K edge (4.37 nm). An outline of a microscope design for single-shot live cell imaging is proposed based on high-Z plasma UTA source, coupled to multilayer mirror optics. (paper)

Characteristics of extreme ultraviolet emission from high-Z plasmas

Science.gov (United States)

Ohashi, H.; Higashiguchi, T.; Suzuki, Y.; Kawasaki, M.; Suzuki, C.; Tomita, K.; Nishikino, M.; Fujioka, S.; Endo, A.; Li, B.; Otsuka, T.; Dunne, P.; O'Sullivan, G.

2016-03-01

We demonstrate the extreme ultraviolet (EUV) and soft x-ray sources in the 2 to 7 nm spectral region related to the beyond EUV (BEUV) question at 6.x nm and the water window source based on laser-produced high-Z plasmas. Resonance emission from multiply charged ions merges to produce intense unresolved transition arrays (UTAs), extending below the carbon K edge (4.37 nm). An outline of a microscope design for single-shot live cell imaging is proposed based on high-Z plasma UTA source, coupled to multilayer mirror optics.

Probability modeling of high flow extremes in Yingluoxia watershed, the upper reaches of Heihe River basin

Science.gov (United States)

Li, Zhanling; Li, Zhanjie; Li, Chengcheng

2014-05-01

Probability modeling of hydrological extremes is one of the major research areas in hydrological science. Most basins in humid and semi-humid south and east of China are concerned for probability modeling analysis of high flow extremes. While, for the inland river basin which occupies about 35% of the country area, there is a limited presence of such studies partly due to the limited data availability and a relatively low mean annual flow. The objective of this study is to carry out probability modeling of high flow extremes in the upper reach of Heihe River basin, the second largest inland river basin in China, by using the peak over threshold (POT) method and Generalized Pareto Distribution (GPD), in which the selection of threshold and inherent assumptions for POT series are elaborated in details. For comparison, other widely used probability distributions including generalized extreme value (GEV), Lognormal, Log-logistic and Gamma are employed as well. Maximum likelihood estimate is used for parameter estimations. Daily flow data at Yingluoxia station from 1978 to 2008 are used. Results show that, synthesizing the approaches of mean excess plot, stability features of model parameters, return level plot and the inherent independence assumption of POT series, an optimum threshold of 340m3/s is finally determined for high flow extremes in Yingluoxia watershed. The resulting POT series is proved to be stationary and independent based on Mann-Kendall test, Pettitt test and autocorrelation test. In terms of Kolmogorov-Smirnov test, Anderson-Darling test and several graphical diagnostics such as quantile and cumulative density function plots, GPD provides the best fit to high flow extremes in the study area. The estimated high flows for long return periods demonstrate that, as the return period increasing, the return level estimates are probably more uncertain. The frequency of high flow extremes exhibits a very slight but not significant decreasing trend from 1978 to

Mitigating the Long term Operating Extreme Load through Active Control

DEFF Research Database (Denmark)

Koukoura, Christina; Natarajan, Anand

2014-01-01

blade azimuth location are shown to affect the extreme blade load magnitude during operation in normal turbulence wind input. The simultaneously controlled operation of generator torque variation and pitch variation at low blade pitch angles is detected to be responsible for very high loads acting...... on the blades. Through gain scheduling of the controller (modifications of the proportional Kp and the integral Ki gains) the extreme loads are mitigated, ensuring minimum instantaneous variations in the power production for operation above rated wind speed. The response of the blade load is examined...

A high-power versatile wireless power transfer for biomedical implants.

Science.gov (United States)

Jiang, Hao; Zhang, Jun Min; Liou, Shy Shenq; Fechter, Richard; Hirose, Shinjiro; Harrison, Michael; Roy, Shuvo

2010-01-01

Implantable biomedical actuators are highly desired in modern medicine. However, how to power up these biomedical implants remains a challenge since most of them need more than several hundreds mW of power. The air-core based radio-frequency transformer (two face-to-face inductive coils) has been the only non-toxic and non-invasive power source for implants for the last three decades [1]. For various technical constraints, the maximum delivered power is limited by this approach. The highest delivered power reported is 275 mW over 1 cm distance [2]. Also, the delivered power is highly vulnerable to the coils' geometrical arrangement and the electrical property of the medium around them. In this paper, a novel rotating-magnets based wireless power transfer that can deliver ∼10 W over 1 cm is demonstrated. The delivered power is significantly higher than the existing start-of-art. Further, the new method is versatile since there is no need to have the impedance matching networks that are highly susceptible to the operating frequency, the coil arrangement and the environment.

Energetic Extremes in Aquatic Locomotion by Coral Reef Fishes

Science.gov (United States)

Fulton, Christopher J.; Johansen, Jacob L.; Steffensen, John F.

2013-01-01

Underwater locomotion is challenging due to the high friction and resistance imposed on a body moving through water and energy lost in the wake during undulatory propulsion. While aquatic organisms have evolved streamlined shapes to overcome such resistance, underwater locomotion has long been considered a costly exercise. Recent evidence for a range of swimming vertebrates, however, has suggested that flapping paired appendages around a rigid body may be an extremely efficient means of aquatic locomotion. Using intermittent flow-through respirometry, we found exceptional energetic performance in the Bluelined wrasse Stethojulis bandanensis, which maintains tuna-like optimum cruising speeds (up to 1 metre s−1) while using 40% less energy than expected for their body size. Displaying an exceptional aerobic scope (22-fold above resting), streamlined rigid-body posture, and wing-like fins that generate lift-based thrust, S. bandanensis literally flies underwater to efficiently maintain high optimum swimming speeds. Extreme energetic performance may be key to the colonization of highly variable environments, such as the wave-swept habitats where S. bandanensis and other wing-finned species tend to occur. Challenging preconceived notions of how best to power aquatic locomotion, biomimicry of such lift-based fin movements could yield dramatic reductions in the power needed to propel underwater vehicles at high speed. PMID:23326566

Energetic extremes in aquatic locomotion by coral reef fishes.

Directory of Open Access Journals (Sweden)

Christopher J Fulton

Full Text Available Underwater locomotion is challenging due to the high friction and resistance imposed on a body moving through water and energy lost in the wake during undulatory propulsion. While aquatic organisms have evolved streamlined shapes to overcome such resistance, underwater locomotion has long been considered a costly exercise. Recent evidence for a range of swimming vertebrates, however, has suggested that flapping paired appendages around a rigid body may be an extremely efficient means of aquatic locomotion. Using intermittent flow-through respirometry, we found exceptional energetic performance in the Bluelined wrasse Stethojulis bandanensis, which maintains tuna-like optimum cruising speeds (up to 1 metre s(-1 while using 40% less energy than expected for their body size. Displaying an exceptional aerobic scope (22-fold above resting, streamlined rigid-body posture, and wing-like fins that generate lift-based thrust, S. bandanensis literally flies underwater to efficiently maintain high optimum swimming speeds. Extreme energetic performance may be key to the colonization of highly variable environments, such as the wave-swept habitats where S. bandanensis and other wing-finned species tend to occur. Challenging preconceived notions of how best to power aquatic locomotion, biomimicry of such lift-based fin movements could yield dramatic reductions in the power needed to propel underwater vehicles at high speed.

Pulsed high-power beams

International Nuclear Information System (INIS)

Reginato, L.L.; Birx, D.L.

1988-01-01

The marriage of induction linac technology with nonlinear magnetic modulators has produced some unique capabilities. It is now possible to produce short-pulse electron beams with average currents measured in amperes, at gradients approaching 1-MeV/m, and with power efficiencies exceeding 50%. This paper reports on a 70-MeV, 3-kA induction accelerator (ETA II) constructed at the Lawrence Livermore National Laboratory that incorporates the pulse technology concepts that have evolved over the past several years. The ETA II is a linear induction accelerator and provides a test facility for demonstration of the high-average-power components and high-brightness sources used in such accelerators. The pulse drive of the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak-power capability, repetition rates exceeding 1 kHz, and excellent reliability

Simulation of the 23 July 2012 Extreme Space Weather Event: What if This Extremely Rare CME Was Earth Directed?

Science.gov (United States)

Ngwira, Chigomezyo M.; Pulkkinen, Antti; Mays, M. Leila; Kuznetsova, Maria M.; Galvin, A. B.; Simunac, Kristin; Baker, Daniel N.; Li, Xinlin; Zheng, Yihua; Glocer, Alex

2013-01-01

Extreme space weather events are known to cause adverse impacts on critical modern day technological infrastructure such as high-voltage electric power transmission grids. On 23 July 2012, NASA's Solar Terrestrial Relations Observatory-Ahead (STEREO-A) spacecraft observed in situ an extremely fast coronal mass ejection (CME) that traveled 0.96 astronomical units (approx. 1 AU) in about 19 h. Here we use the SpaceWeather Modeling Framework (SWMF) to perform a simulation of this rare CME.We consider STEREO-A in situ observations to represent the upstream L1 solar wind boundary conditions. The goal of this study is to examine what would have happened if this Rare-type CME was Earth-bound. Global SWMF-generated ground geomagnetic field perturbations are used to compute the simulated induced geoelectric field at specific ground-based active INTERMAGNET magnetometer sites. Simulation results show that while modeled global SYM-H index, a high-resolution equivalent of the Dst index, was comparable to previously observed severe geomagnetic storms such as the Halloween 2003 storm, the 23 July CME would have produced some of the largest geomagnetically induced electric fields, making it very geoeffective. These results have important practical applications for risk management of electrical power grids.

Peak power ratio generator

Science.gov (United States)

Moyer, R.D.

A peak power ratio generator is described for measuring, in combination with a conventional power meter, the peak power level of extremely narrow pulses in the gigahertz radio frequency bands. The present invention in a preferred embodiment utilizes a tunnel diode and a back diode combination in a detector circuit as the only high speed elements. The high speed tunnel diode provides a bistable signal and serves as a memory device of the input pulses for the remaining, slower components. A hybrid digital and analog loop maintains the peak power level of a reference channel at a known amount. Thus, by measuring the average power levels of the reference signal and the source signal, the peak power level of the source signal can be determined.

A battery-powered high-current power supply for superconductors

CERN Document Server

Wake, M; Suda, K

2002-01-01

Since superconductors do not require voltages, a high-current power supply could run with low power if the voltage is sufficiently reduced. Even a battery-powered power supply could give as much as 2,000A for a superconductor. To demonstrate this hypothesis, a battery-powered 2,000A power supply was constructed. It uses an IGBT chopper and Schottky diode together with a specially arranged transformer to produce a high current with low voltage. Testing of 2,000A operation was performed for about 1.5 hr using 10 car batteries. Charging time for this operation was 8 hr. Ramping control was smooth and caused no trouble. Although the IGBT frequency ripple of 16.6 kHz was easily removed using a passive filter, spike noise remained in the output voltage. This ripple did not cause any trouble in operating a pancake-type inductive superconducting load. (author)

High-field, high-density tokamak power reactor

International Nuclear Information System (INIS)

Cohn, D.R.; Cook, D.L.; Hay, R.D.; Kaplan, D.; Kreischer, K.; Lidskii, L.M.; Stephany, W.; Williams, J.E.C.; Jassby, D.L.; Okabayashi, M.

1977-11-01

A conceptual design of a compact (R 0 = 6.0 m) high power density (average P/sub f/ = 7.7 MW/m 3 ) tokamak demonstration power reactor has been developed. High magnetic field (B/sub t/ = 7.4 T) and moderate elongation (b/a = 1.6) permit operation at the high density (n(0) approximately 5 x 10 14 cm -3 ) needed for ignition in a relatively small plasma, with a spatially-averaged toroidal beta of only 4%. A unique design for the Nb 3 Sn toroidal-field magnet system reduces the stress in the high-field trunk region, and allows modularization for simpler disassembly. The modest value of toroidal beta permits a simple, modularized plasma-shaping coil system, located inside the TF coil trunk. Heating of the dense central plasma is attained by the use of ripple-assisted injection of 120-keV D 0 beams. The ripple-coil system also affords dynamic control of the plasma temperature during the burn period. A FLIBE-lithium blanket is designed especially for high-power-density operation in a high-field environment, and gives an overall tritium breeding ratio of 1.05 in the slowly pumped lithium

High Energy Ion Acceleration by Extreme Laser Radiation Pressure

Science.gov (United States)

2017-03-14

published in the internationally leading journal Physical Review Letters. We continued to progress this pionee 15.  SUBJECT TERMS ion therapy, heavy ion ...Thomson parabola spectrometer: To separate and provide a measurement of the charge -to-mass ratio and energy spectrum of the different ion species...AFRL-AFOSR-UK-TR-2017-0015 High energy ion acceleration by extreme laser radiation pressure Paul McKenna UNIVERSITY OF STRATHCLYDE VIZ ROYAL COLLEGE

Applications of high power microwaves

International Nuclear Information System (INIS)

Benford, J.; Swegle, J.

1993-01-01

The authors address a number of applications for HPM technology. There is a strong symbiotic relationship between a developing technology and its emerging applications. New technologies can generate new applications. Conversely, applications can demand development of new technological capability. High-power microwave generating systems come with size and weight penalties and problems associated with the x-radiation and collection of the electron beam. Acceptance of these difficulties requires the identification of a set of applications for which high-power operation is either demanded or results in significant improvements in peRFormance. The authors identify the following applications, and discuss their requirements and operational issues: (1) High-energy RF acceleration; (2) Atmospheric modification (both to produce artificial ionospheric mirrors for radio waves and to save the ozone layer); (3) Radar; (4) Electronic warfare; and (5) Laser pumping. In addition, they discuss several applications requiring high average power than border on HPM, power beaming and plasma heating

Cutting and drilling studies using high power visible lasers

International Nuclear Information System (INIS)

Kautz, D.D.; Dragon, E.P.; Werve, M.E.; Hargrove, R.S.; Warner, B.E.

1993-01-01

High power and radiance laser technologies developed at Lawrence Livermore National Laboratory such as copper-vapor and dye lasers show great promise for material processing tasks. Evaluation of models suggests significant increases in welding, cutting, and drilling capabilities, as well as applications in emerging technologies such as micromachining, surface treatment, and stereolithography. Copper lasers currently operate at 1.8 kW output at approximately three times the diffraction limit and achieve mean time between failures of more than 1,000 hours. Dye lasers have near diffraction limited beam quality at greater than 1.0 kW. Results from cutting and drilling studies in titanium and stainless steel alloys show that cuts and holes with extremely fine features can be made with dye and copper-vapor lasers. High radiance beams produce low distortion and small heat-affected zones. The authors have accomplished very high aspect ratios (> 60:1) and features with micron scale (5-50 μm) sizes. The paper gives a description of the equipment; discusses cutting theory; and gives experimental results of cutting and drilling studies on Ti-6Al-4V and 304 stainless steel

Optics assembly for high power laser tools

Science.gov (United States)

Fraze, Jason D.; Faircloth, Brian O.; Zediker, Mark S.

2016-06-07

There is provided a high power laser rotational optical assembly for use with, or in high power laser tools for performing high power laser operations. In particular, the optical assembly finds applications in performing high power laser operations on, and in, remote and difficult to access locations. The optical assembly has rotational seals and bearing configurations to avoid contamination of the laser beam path and optics.

A web-based study of bipolarity and impulsivity in athletes engaging in extreme and high-risk sports.

Science.gov (United States)

Dudek, Dominika; Siwek, Marcin; Jaeschke, Rafał; Drozdowicz, Katarzyna; Styczeń, Krzysztof; Arciszewska, Aleksandra; Chrobak, Adrian A; Rybakowski, Janusz K

2016-06-01

We hypothesised that men and women who engage in extreme or high-risk sports would score higher on standardised measures of bipolarity and impulsivity compared to age and gender matched controls. Four-hundred and eighty extreme or high-risk athletes (255 males and 225 females) and 235 age-matched control persons (107 males and 128 females) were enrolled into the web-based case-control study. The Mood Disorder Questionnaire (MDQ) and Barratt Impulsiveness Scale (BIS-11) were administered to screen for bipolarity and impulsive behaviours, respectively. Results indicated that extreme or high-risk athletes had significantly higher scores of bipolarity and impulsivity, and lower scores on cognitive complexity of the BIS-11, compared to controls. Further, there were positive correlations between the MDQ and BIS-11 scores. These results showed greater rates of bipolarity and impulsivity, in the extreme or high-risk athletes, suggesting these measures are sensitive to high-risk behaviours.

HIGH AVERAGE POWER OPTICAL FEL AMPLIFIERS

International Nuclear Information System (INIS)

2005-01-01

Historically, the first demonstration of the optical FEL was in an amplifier configuration at Stanford University [l]. There were other notable instances of amplifying a seed laser, such as the LLNL PALADIN amplifier [2] and the BNL ATF High-Gain Harmonic Generation FEL [3]. However, for the most part FELs are operated as oscillators or self amplified spontaneous emission devices. Yet, in wavelength regimes where a conventional laser seed can be used, the FEL can be used as an amplifier. One promising application is for very high average power generation, for instance FEL's with average power of 100 kW or more. The high electron beam power, high brightness and high efficiency that can be achieved with photoinjectors and superconducting Energy Recovery Linacs (ERL) combine well with the high-gain FEL amplifier to produce unprecedented average power FELs. This combination has a number of advantages. In particular, we show that for a given FEL power, an FEL amplifier can introduce lower energy spread in the beam as compared to a traditional oscillator. This properly gives the ERL based FEL amplifier a great wall-plug to optical power efficiency advantage. The optics for an amplifier is simple and compact. In addition to the general features of the high average power FEL amplifier, we will look at a 100 kW class FEL amplifier is being designed to operate on the 0.5 ampere Energy Recovery Linac which is under construction at Brookhaven National Laboratory's Collider-Accelerator Department

Application of high power microwave vacuum electron devices

International Nuclear Information System (INIS)

Ding Yaogen; Liu Pukun; Zhang Zhaochuan; Wang Yong; Shen Bin

2011-01-01

High power microwave vacuum electron devices can work at high frequency, high peak and average power. They have been widely used in military and civil microwave electron systems, such as radar, communication,countermeasure, TV broadcast, particle accelerators, plasma heating devices of fusion, microwave sensing and microwave heating. In scientific research, high power microwave vacuum electron devices are used mainly on high energy particle accelerator and fusion research. The devices include high peak power klystron, CW and long pulse high power klystron, multi-beam klystron,and high power gyrotron. In national economy, high power microwave vacuum electron devices are used mainly on weather and navigation radar, medical and radiation accelerator, TV broadcast and communication system. The devices include high power pulse and CW klystron, extended interaction klystron, traveling wave tube (TWT), magnetron and induced output tube (IOT). The state of art, common technology problems and trends of high power microwave vacuum electron devices are introduced in this paper. (authors)

14 CFR 101.25 - Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets.

Science.gov (United States)

2010-01-01

... Power Rockets and Class 3-Advanced High Power Rockets. 101.25 Section 101.25 Aeronautics and Space... OPERATING RULES MOORED BALLOONS, KITES, AMATEUR ROCKETS AND UNMANNED FREE BALLOONS Amateur Rockets § 101.25 Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets. When operating...

Lower-extremity resistance training on unstable surfaces improves proxies of muscle strength, power and balance in healthy older adults: a randomised control trial

Directory of Open Access Journals (Sweden)

Nils Eckardt

2016-11-01

Full Text Available Abstract Background It is well documented that both balance and resistance training have the potential to mitigate intrinsic fall risk factors in older adults. However, knowledge about the effects of simultaneously executed balance and resistance training (i.e., resistance training conducted on unstable surfaces [URT] on lower-extremity muscle strength, power and balance in older adults is insufficient. The objective of the present study was to compare the effects of machine-based stable resistance training (M-SRT and two types of URT, i.e., machine-based (M-URT and free-weight URT (F-URT, on measures of lower-extremity muscle strength, power and balance in older adults. Methods Seventy-five healthy community-dwelling older adults aged 65–80 years, were assigned to three intervention groups: M-SRT, M-URT and F-URT. Over a period of ten weeks, all participants exercised two times per week with each session lasting ~60 min. Tests included assessment of leg muscle strength (e.g., maximal isometric leg extension strength, power (e.g., chair rise test and balance (e.g., functional reach test, carried out before and after the training period. Furthermore, maximal training load of the squat-movement was assessed during the last training week. Results Maximal training load of the squat-movement was significantly lower in F-URT in comparison to M-SRT and M-URT. However, lower-extremity resistance training conducted on even and uneven surfaces meaningfully improved proxies of strength, power and balance in all groups. M-URT produced the greatest improvements in leg extension strength and F-URT in the chair rise test and functional reach test. Conclusion Aside from two interaction effects, overall improvements in measures of lower-extremity muscle strength, power and balance were similar across training groups. Importantly, F-URT produced similar results with considerably lower training load as compared to M-SRT and M-URT. Concluding, F-URT seems an

High-frequency high-voltage high-power DC-to-DC converters

Science.gov (United States)

Wilson, T. G.; Owen, H. A.; Wilson, P. M.

1982-09-01

A simple analysis of the current and voltage waveshapes associated with the power transistor and the power diode in an example current-or-voltage step-up (buck-boost) converter is presented. The purpose of the analysis is to provide an overview of the problems and design trade-offs which must be addressed as high-power high-voltage converters are operated at switching frequencies in the range of 100 kHz and beyond. Although the analysis focuses on the current-or-voltage step-up converter as the vehicle for discussion, the basic principles presented are applicable to other converter topologies as well.

Analysis of extreme events

CSIR Research Space (South Africa)

Khuluse, S

2009-04-01

Full Text Available ) determination of the distribution of the damage and (iii) preparation of products that enable prediction of future risk events. The methodology provided by extreme value theory can also be a powerful tool in risk analysis...

High-power, high-efficiency FELs

International Nuclear Information System (INIS)

Sessler, A.M.

1989-04-01

High power, high efficiency FELs require tapering, as the particles loose energy, so as to maintain resonance between the electromagnetic wave and the particles. They also require focusing of the particles (usually done with curved pole faces) and focusing of the electromagnetic wave (i.e. optical guiding). In addition, one must avoid transverse beam instabilities (primarily resistive wall) and longitudinal instabilities (i.e sidebands). 18 refs., 7 figs., 3 tabs

The generation of high-power charge particle micro beams and its interaction with condensed matter

International Nuclear Information System (INIS)

Vogel, N.; Skvortsov, V.A.

1996-01-01

As has been observed experimentally, the action of a picosecond laser beam on an Al-target in air gives rise to the generation and acceleration of high-power micro electron and ion beams. An original theoretical model for describing the generation and particle acceleration of such micro beams as a result of the micro channeling effect is presented. It was found that extreme states of matter, with compression in the Gbar pressure range, can be produced by such micro beams. (author). 3 figs., 12 refs

Water Vapour Propulsion Powered by a High-Power Laser-Diode

Science.gov (United States)

Minami, Y.; Uchida, S.

Most of the laser propulsion schemes now being proposed and developed assume neither power supplies nor on-board laser devices and therefore are bound to remote laser stations like a kite via a laser beam “string”. This is a fatal disadvantage for a space vehicle that flies freely though it is often said that no need of installing an energy source is an advantage of a laser propulsion scheme. The possibility of an independent laser propulsion space vehicle that carries a laser source and a power supply on board is discussed. This is mainly due to the latest development of high power laser diode (LD) technology. Both high specific impulse-low thrust mode and high thrust-low specific impulse mode can be selected by controlling the laser output by using vapour or water as a propellant. This mode change can be performed by switching between a high power continuous wave (cw), LD engine for high thrust with a low specific impulse mode and high power LD pumping Q-switched Nd:YAG laser engine for low thrust with the high specific impulse mode. This paper describes an Orbital Transfer Vehicle equipped with the above-mentioned laser engine system and fuel cell that flies to the Moon from a space platform or space hotel in Earth orbit, with cargo shipment from lunar orbit to the surface of the Moon, including the possibility of a sightseeing trip.

The evolution of extreme precipitations in high resolution scenarios over France

Science.gov (United States)

Colin, J.; Déqué, M.; Somot, S.

2009-09-01

Over the past years, improving the modelling of extreme events and their variability at climatic time scales has become one of the challenging issue raised in the regional climate research field. This study shows the results of a high resolution (12 km) scenario run over France with the limited area model (LAM) ALADIN-Climat, regarding the representation of extreme precipitations. The runs were conducted in the framework of the ANR-SCAMPEI national project on high resolution scenarios over French mountains. As a first step, we attempt to quantify one of the uncertainties implied by the use of LAM : the size of the area on which the model is run. In particular, we address the issue of whether a relatively small domain allows the model to create its small scale process. Indeed, high resolution scenarios cannot be run on large domains because of the computation time. Therefore one needs to answer this preliminary question before producing and analyzing such scenarios. To do so, we worked in the framework of a « big brother » experiment. We performed a 23-year long global simulation in present-day climate (1979-2001) with the ARPEGE-Climat GCM, at a resolution of approximately 50 km over Europe (stretched grid). This first simulation, named ARP50, constitutes the « big brother » reference of our experiment. It has been validated in comparison with the CRU climatology. Then we filtered the short waves (up to 200 km) from ARP50 in order to obtain the equivalent of coarse resolution lateral boundary conditions (LBC). We have carried out three ALADIN-Climat simulations at a 50 km resolution with these LBC, using different configurations of the model : * FRA50, run over a small domain (2000 x 2000 km, centered over France), * EUR50, run over a larger domain (5000 x 5000 km, centered over France as well), * EUR50-SN, run over the large domain (using spectral nudging). Considering the facts that ARPEGE-Climat and ALADIN-Climat models share the same physics and dynamics

Fabrication of surfaces with extremely high contact angle hysteresis from polyelectrolyte multilayer.

Science.gov (United States)

Wang, Liming; Wei, Jingjing; Su, Zhaohui

2011-12-20

High contact angle hysteresis on polyelectrolyte multilayers (PEMs) ion-paired with hydrophobic perfluorooctanoate anions is reported. Both the bilayer number of PEMs and the ionic strength of deposition solutions have significant influence on contact angle hysteresis: higher ionic strength and greater bilayer number cause increased contact angle hysteresis values. The hysteresis values of ~100° were observed on smooth PEMs and pinning of the receding contact line on hydrophilic defects is implicated as the cause of hysteresis. Surface roughness can be used to further tune the contact angle hysteresis on the PEMs. A surface with extremely high contact angle hysteresis of 156° was fabricated when a PEM was deposited on a rough substrate coated with submicrometer scale silica spheres. It was demonstrated that this extremely high value of contact angle hysteresis resulted from the penetration of water into the rough asperities on the substrate. The same substrate hydrophobized by chemical vapor deposition of 1H,1H,2H,2H-perfluorooctyltriethoxysilane exhibits high advancing contact angle and low hysteresis. © 2011 American Chemical Society

High speed micromachining with high power UV laser

Science.gov (United States)

Patel, Rajesh S.; Bovatsek, James M.

2013-03-01

Increasing demand for creating fine features with high accuracy in manufacturing of electronic mobile devices has fueled growth for lasers in manufacturing. High power, high repetition rate ultraviolet (UV) lasers provide an opportunity to implement a cost effective high quality, high throughput micromachining process in a 24/7 manufacturing environment. The energy available per pulse and the pulse repetition frequency (PRF) of diode pumped solid state (DPSS) nanosecond UV lasers have increased steadily over the years. Efficient use of the available energy from a laser is important to generate accurate fine features at a high speed with high quality. To achieve maximum material removal and minimal thermal damage for any laser micromachining application, use of the optimal process parameters including energy density or fluence (J/cm2), pulse width, and repetition rate is important. In this study we present a new high power, high PRF QuasarR 355-40 laser from Spectra-Physics with TimeShiftTM technology for unique software adjustable pulse width, pulse splitting, and pulse shaping capabilities. The benefits of these features for micromachining include improved throughput and quality. Specific example and results of silicon scribing are described to demonstrate the processing benefits of the Quasar's available power, PRF, and TimeShift technology.

Power affects performance when the pressure is on: evidence for low-power threat and high-power lift.

Science.gov (United States)

Kang, Sonia K; Galinsky, Adam D; Kray, Laura J; Shirako, Aiwa

2015-05-01

The current research examines how power affects performance in pressure-filled contexts. We present low-power-threat and high-power-lift effects, whereby performance in high-stakes situations suffers or is enhanced depending on one's power; that is, the power inherent to a situational role can produce effects similar to stereotype threat and lift. Three negotiations experiments demonstrate that role-based power affects outcomes but only when the negotiation is diagnostic of ability and, therefore, pressure-filled. We link these outcomes conceptually to threat and lift effects by showing that (a) role power affects performance more strongly when the negotiation is diagnostic of ability and (b) underperformance disappears when the low-power negotiator has an opportunity to self-affirm. These results suggest that stereotype threat and lift effects may represent a more general phenomenon: When the stakes are raised high, relative power can act as either a toxic brew (stereotype/low-power threat) or a beneficial elixir (stereotype/high-power lift) for performance. © 2015 by the Society for Personality and Social Psychology, Inc.

Thermal Implications for Extreme Fast Charge

Energy Technology Data Exchange (ETDEWEB)

Keyser, Matthew A [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-08-14

Present-day thermal management systems for battery electric vehicles are inadequate in limiting the maximum temperature rise of the battery during extreme fast charging. If the battery thermal management system is not designed correctly, the temperature of the cells could reach abuse temperatures and potentially send the cells into thermal runaway. Furthermore, the cell and battery interconnect design needs to be improved to meet the lifetime expectations of the consumer. Each of these aspects is explored and addressed as well as outlining where the heat is generated in a cell, the efficiencies of power and energy cells, and what type of battery thermal management solutions are available in today's market. Thermal management is not a limiting condition with regard to extreme fast charging, but many factors need to be addressed especially for future high specific energy density cells to meet U.S. Department of Energy cost and volume goals.

Probabilistic analysis of extreme wind events

Energy Technology Data Exchange (ETDEWEB)

Chaviaropoulos, P.K. [Center for Renewable Energy Sources (CRES), Pikermi Attikis (Greece)

1997-12-31

A vital task in wind engineering and meterology is to understand, measure, analyse and forecast extreme wind conditions, due to their significant effects on human activities and installations like buildings, bridges or wind turbines. The latest version of the IEC standard (1996) pays particular attention to the extreme wind events that have to be taken into account when designing or certifying a wind generator. Actually, the extreme wind events within a 50 year period are those which determine the ``static`` design of most of the wind turbine components. The extremes which are important for the safety of wind generators are those associated with the so-called ``survival wind speed``, the extreme operating gusts and the extreme wind direction changes. A probabilistic approach for the analysis of these events is proposed in this paper. Emphasis is put on establishing the relation between extreme values and physically meaningful ``site calibration`` parameters, like probability distribution of the annual wind speed, turbulence intensity and power spectra properties. (Author)

Advanced High Voltage Power Device Concepts

CERN Document Server

Baliga, B Jayant

2012-01-01

Advanced High Voltage Power Device Concepts describes devices utilized in power transmission and distribution equipment, and for very high power motor control in electric trains and steel-mills. Since these devices must be capable of supporting more than 5000-volts in the blocking mode, this books covers operation of devices rated at 5,000-V, 10,000-V and 20,000-V. Advanced concepts (the MCT, the BRT, and the EST) that enable MOS-gated control of power thyristor structures are described and analyzed in detail. In addition, detailed analyses of the silicon IGBT, as well as the silicon carbide MOSFET and IGBT, are provided for comparison purposes. Throughout the book, analytical models are generated to give a better understanding of the physics of operation for all the structures. This book provides readers with: The first comprehensive treatment of high voltage (over 5000-volts) power devices suitable for the power distribution, traction, and motor-control markets;  Analytical formulations for all the device ...

Laser waveform control of extreme ultraviolet high harmonics from solids.

Science.gov (United States)

You, Yong Sing; Wu, Mengxi; Yin, Yanchun; Chew, Andrew; Ren, Xiaoming; Gholam-Mirzaei, Shima; Browne, Dana A; Chini, Michael; Chang, Zenghu; Schafer, Kenneth J; Gaarde, Mette B; Ghimire, Shambhu

2017-05-01

Solid-state high-harmonic sources offer the possibility of compact, high-repetition-rate attosecond light emitters. However, the time structure of high harmonics must be characterized at the sub-cycle level. We use strong two-cycle laser pulses to directly control the time-dependent nonlinear current in single-crystal MgO, leading to the generation of extreme ultraviolet harmonics. We find that harmonics are delayed with respect to each other, yielding an atto-chirp, the value of which depends on the laser field strength. Our results provide the foundation for attosecond pulse metrology based on solid-state harmonics and a new approach to studying sub-cycle dynamics in solids.

Effect of Enhanced Air Temperature (extreme heat, and Load of Non-Linear Against the Use of Electric Power

Directory of Open Access Journals (Sweden)

I Ketut Wijaya

2015-12-01

Full Text Available Usage Electric power is very easy to do, because the infrastructure for connecting  already available and widely sold. Consumption electric power is not accompanied by the ability to recognize electric power. The average increase of electricity power in Bali in extreme weather reaches 10% in years 2014, so that Bali suffered power shortages and PLN as the manager of electric power to perform scheduling on of electric power usage. Scheduling is done because many people use electric power as the load  of fan and Air Conditioner exceeding the previous time. Load of fan, air conditioning, and computers including non-linear loads which can add heat on the conductor of electricity. Non-linear load and hot weather can lead to heat on conductor so  insulation damaged  and cause electrical short circuit. Data of electric power obtained through questionnaires, surveys, measurement and retrieve data from various parties. Fires that occurred in 2014, namely 109 events, 44 is  event caused by an electric short circuit (approximately 40%. Decrease power factors can cause losses of electricity and hot. Heat can cause and adds heat on the  conductor electric. The analysis showed  understanding electric power of the average  is 27,700 with value between 20 to 40. So an understanding of the electrical power away from the understand so that many errors because of the act own. Installation tool ELCB very necessary but very necessary provide counseling   of electricity to the community.

High-power density miniscale power generation and energy harvesting systems

International Nuclear Information System (INIS)

Lyshevski, Sergey Edward

2011-01-01

This paper reports design, analysis, evaluations and characterization of miniscale self-sustained power generation systems. Our ultimate objective is to guarantee highly-efficient mechanical-to-electrical energy conversion, ensure premier wind- or hydro-energy harvesting capabilities, enable electric machinery and power electronics solutions, stabilize output voltage, etc. By performing the advanced scalable power generation system design, we enable miniscale energy sources and energy harvesting technologies. The proposed systems integrate: (1) turbine which rotates a radial- or axial-topology permanent-magnet synchronous generator at variable angular velocity depending on flow rate, speed and load, and, (2) power electronic module with controllable rectifier, soft-switching converter and energy storage stages. These scalable energy systems can be utilized as miniscale auxiliary and self-sustained power units in various applications, such as, aerospace, automotive, biotechnology, biomedical, and marine. The proposed systems uniquely suit various submersible and harsh environment applications. Due to operation in dynamic rapidly-changing envelopes (variable speed, load changes, etc.), sound solutions are researched, proposed and verified. We focus on enabling system organizations utilizing advanced developments for various components, such as generators, converters, and energy storage. Basic, applied and experimental findings are reported. The prototypes of integrated power generation systems were tested, characterized and evaluated. It is documented that high-power density, high efficiency, robustness and other enabling capabilities are achieved. The results and solutions are scalable from micro (∼100 μW) to medium (∼100 kW) and heavy-duty (sub-megawatt) auxiliary and power systems.

Power MOSFET Linearizer of a High-Voltage Power Amplifier for High-Frequency Pulse-Echo Instrumentation.

Science.gov (United States)

Choi, Hojong; Woo, Park Chul; Yeom, Jung-Yeol; Yoon, Changhan

2017-04-04

A power MOSFET linearizer is proposed for a high-voltage power amplifier (HVPA) used in high-frequency pulse-echo instrumentation. The power MOSFET linearizer is composed of a DC bias-controlled series power MOSFET shunt with parallel inductors and capacitors. The proposed scheme is designed to improve the gain deviation characteristics of the HVPA at higher input powers. By controlling the MOSFET bias voltage in the linearizer, the gain reduction into the HVPA was compensated, thereby reducing the echo harmonic distortion components generated by the ultrasonic transducers. In order to verify the performance improvement of the HVPA implementing the power MOSFET linearizer, we measured and found that the gain deviation of the power MOSFET linearizer integrated with HVPA under 10 V DC bias voltage was reduced (-1.8 and -0.96 dB, respectively) compared to that of the HVPA without the power MOSFET linearizer (-2.95 and -3.0 dB, respectively) when 70 and 80 MHz, three-cycle, and 26 dB m input pulse waveforms are applied, respectively. The input 1-dB compression point (an index of linearity) of the HVPA with power MOSFET linearizer (24.17 and 26.19 dB m at 70 and 80 MHz, respectively) at 10 V DC bias voltage was increased compared to that of HVPA without the power MOSFET linearizer (22.03 and 22.13 dB m at 70 and 80 MHz, respectively). To further verify the reduction of the echo harmonic distortion components generated by the ultrasonic transducers, the pulse-echo responses in the pulse-echo instrumentation were compared when using HVPA with and without the power MOSFET linearizer. When three-cycle 26 dB m input power was applied, the second, third, fourth, and fifth harmonic distortion components of a 75 MHz transducer driven by the HVPA with power MOSFET linearizer (-48.34, -44.21, -48.34, and -46.56 dB, respectively) were lower than that of the HVPA without the power MOSFET linearizer (-45.61, -41.57, -45.01, and -45.51 dB, respectively). When five-cycle 20 dB m input

High Power Orbit Transfer Vehicle

National Research Council Canada - National Science Library

Gulczinski, Frank

2003-01-01

... from Virginia Tech University and Aerophysics, Inc. to examine propulsion requirements for a high-power orbit transfer vehicle using thin-film voltaic solar array technologies under development by the Space Vehicles Directorate (dubbed PowerSail...

High impact data visualization with Power View, Power Map, and Power BI

CERN Document Server

Aspin, Adam

2014-01-01

High Impact Data Visualization with Power View, Power Map, and Power BI helps you take business intelligence delivery to a new level that is interactive, engaging, even fun, all while driving commercial success through sound decision-making. Learn to harness the power of Microsoft's flagship, self-service business intelligence suite to deliver compelling and interactive insight with remarkable ease. Learn the essential techniques needed to enhance the look and feel of reports and dashboards so that you can seize your audience's attention and provide them with clear and accurate information. Al

Eighth CW and High Average Power RF Workshop

CERN Document Server

2014-01-01

We are pleased to announce the next Continuous Wave and High Average RF Power Workshop, CWRF2014, to take place at Hotel NH Trieste, Trieste, Italy from 13 to 16 May, 2014. This is the eighth in the CWRF workshop series and will be hosted by Elettra - Sincrotrone Trieste S.C.p.A. (www.elettra.eu). CWRF2014 will provide an opportunity for designers and users of CW and high average power RF systems to meet and interact in a convivial environment to share experiences and ideas on applications which utilize high-power klystrons, gridded tubes, combined solid-state architectures, high-voltage power supplies, high-voltage modulators, high-power combiners, circulators, cavities, power couplers and tuners. New ideas for high-power RF system upgrades and novel ways of RF power generation and distribution will also be discussed. CWRF2014 sessions will start on Tuesday morning and will conclude on Friday lunchtime. A visit to Elettra and FERMI will be organized during the workshop. ORGANIZING COMMITTEE (OC): Al...

Extreme seismicity and disaster risks: Hazard versus vulnerability (Invited)

Science.gov (United States)

Ismail-Zadeh, A.

2013-12-01

Although the extreme nature of earthquakes has been known for millennia due to the resultant devastation from many of them, the vulnerability of our civilization to extreme seismic events is still growing. It is partly because of the increase in the number of high-risk objects and clustering of populations and infrastructure in the areas prone to seismic hazards. Today an earthquake may affect several hundreds thousand lives and cause significant damage up to hundred billion dollars; it can trigger an ecological catastrophe if occurs in close vicinity to a nuclear power plant. Two types of extreme natural events can be distinguished: (i) large magnitude low probability events, and (ii) the events leading to disasters. Although the first-type events may affect earthquake-prone countries directly or indirectly (as tsunamis, landslides etc.), the second-type events occur mainly in economically less-developed countries where the vulnerability is high and the resilience is low. Although earthquake hazards cannot be reduced, vulnerability to extreme events can be diminished by monitoring human systems and by relevant laws preventing an increase in vulnerability. Significant new knowledge should be gained on extreme seismicity through observations, monitoring, analysis, modeling, comprehensive hazard assessment, prediction, and interpretations to assist in disaster risk analysis. The advanced disaster risk communication skill should be developed to link scientists, emergency management authorities, and the public. Natural, social, economic, and political reasons leading to disasters due to earthquakes will be discussed.

SOI N-Channel Field Effect Transistors, CHT-NMOS80, for Extreme Temperatures

Science.gov (United States)

Patterson, Richard L.; Hammoud, Almad

2009-01-01

Extreme temperatures, both hot and cold, are anticipated in many of NASA space exploration missions as well as in terrestrial applications. One can seldom find electronics that are capable of operation under both regimes. Even for operation under one (hot or cold) temperature extreme, some thermal controls need to be introduced to provide appropriate ambient temperatures so that spacecraft on-board or field on-site electronic systems work properly. The inclusion of these controls, which comprise of heating elements and radiators along with their associated structures, adds to the complexity in the design of the system, increases cost and weight, and affects overall reliability. Thus, it would be highly desirable and very beneficial to eliminate these thermal measures in order to simplify system's design, improve efficiency, reduce development and launch costs, and improve reliability. These requirements can only be met through the development of electronic parts that are designed for proper and efficient operation under extreme temperature conditions. Silicon-on-insulator (SOI) based devices are finding more use in harsh environments due to the benefits that their inherent design offers in terms of reduced leakage currents, less power consumption, faster switching speeds, good radiation tolerance, and extreme temperature operability. Little is known, however, about their performance at cryogenic temperatures and under wide thermal swings. The objective of this work was to evaluate the performance of a new commercial-off-the-shelf (COTS) SOI parts over an extended temperature range and to determine the effects of thermal cycling on their performance. The results will establish a baseline on the suitability of such devices for use in space exploration missions under extreme temperatures, and will aid mission planners and circuit designers in the proper selection of electronic parts and circuits. The electronic part investigated in this work comprised of a CHT-NMOS80

Series-Tuned High Efficiency RF-Power Amplifiers

DEFF Research Database (Denmark)

Vidkjær, Jens

2008-01-01

An approach to high efficiency RF-power amplifier design is presented. It addresses simultaneously efficiency optimization and peak voltage limitations when transistors are pushed towards their power limits.......An approach to high efficiency RF-power amplifier design is presented. It addresses simultaneously efficiency optimization and peak voltage limitations when transistors are pushed towards their power limits....

High-power density miniscale power generation and energy harvesting systems

Energy Technology Data Exchange (ETDEWEB)

Lyshevski, Sergey Edward [Department of Electrical and Microelectronics Engineering, Rochester Institute of Technology, Rochester, NY 14623-5603 (United States)

2011-01-15

This paper reports design, analysis, evaluations and characterization of miniscale self-sustained power generation systems. Our ultimate objective is to guarantee highly-efficient mechanical-to-electrical energy conversion, ensure premier wind- or hydro-energy harvesting capabilities, enable electric machinery and power electronics solutions, stabilize output voltage, etc. By performing the advanced scalable power generation system design, we enable miniscale energy sources and energy harvesting technologies. The proposed systems integrate: (1) turbine which rotates a radial- or axial-topology permanent-magnet synchronous generator at variable angular velocity depending on flow rate, speed and load, and, (2) power electronic module with controllable rectifier, soft-switching converter and energy storage stages. These scalable energy systems can be utilized as miniscale auxiliary and self-sustained power units in various applications, such as, aerospace, automotive, biotechnology, biomedical, and marine. The proposed systems uniquely suit various submersible and harsh environment applications. Due to operation in dynamic rapidly-changing envelopes (variable speed, load changes, etc.), sound solutions are researched, proposed and verified. We focus on enabling system organizations utilizing advanced developments for various components, such as generators, converters, and energy storage. Basic, applied and experimental findings are reported. The prototypes of integrated power generation systems were tested, characterized and evaluated. It is documented that high-power density, high efficiency, robustness and other enabling capabilities are achieved. The results and solutions are scalable from micro ({proportional_to}100 {mu}W) to medium ({proportional_to}100 kW) and heavy-duty (sub-megawatt) auxiliary and power systems. (author)

Image-based motion compensation for high-resolution extremities cone-beam CT

Science.gov (United States)

Sisniega, A.; Stayman, J. W.; Cao, Q.; Yorkston, J.; Siewerdsen, J. H.; Zbijewski, W.

2016-03-01

Purpose: Cone-beam CT (CBCT) of the extremities provides high spatial resolution, but its quantitative accuracy may be challenged by involuntary sub-mm patient motion that cannot be eliminated with simple means of external immobilization. We investigate a two-step iterative motion compensation based on a multi-component metric of image sharpness. Methods: Motion is considered with respect to locally rigid motion within a particular region of interest, and the method supports application to multiple locally rigid regions. Motion is estimated by maximizing a cost function with three components: a gradient metric encouraging image sharpness, an entropy term that favors high contrast and penalizes streaks, and a penalty term encouraging smooth motion. Motion compensation involved initial coarse estimation of gross motion followed by estimation of fine-scale displacements using high resolution reconstructions. The method was evaluated in simulations with synthetic motion (1-4 mm) applied to a wrist volume obtained on a CMOS-based CBCT testbench. Structural similarity index (SSIM) quantified the agreement between motion-compensated and static data. The algorithm was also tested on a motion contaminated patient scan from dedicated extremities CBCT. Results: Excellent correction was achieved for the investigated range of displacements, indicated by good visual agreement with the static data. 10-15% improvement in SSIM was attained for 2-4 mm motions. The compensation was robust against increasing motion (4% decrease in SSIM across the investigated range, compared to 14% with no compensation). Consistent performance was achieved across a range of noise levels. Significant mitigation of artifacts was shown in patient data. Conclusion: The results indicate feasibility of image-based motion correction in extremities CBCT without the need for a priori motion models, external trackers, or fiducials.

high power facto high power factor high power factor hybrid rectifier

African Journals Online (AJOL)

eobe

increase in the number of electrical loads that some kind of ... components in the AC power system. Thus, suppl ... al output power; assuring reliability in ... distribution systems. This can be ...... Thesis- Califonia Institute of Technology, Capitulo.

Atmospheric and Fog Effects on Ultra-Wide Band Radar Operating at Extremely High Frequencies.

Science.gov (United States)

Balal, Nezah; Pinhasi, Gad A; Pinhasi, Yosef

2016-05-23

The wide band at extremely high frequencies (EHF) above 30 GHz is applicable for high resolution directive radars, resolving the lack of free frequency bands within the lower part of the electromagnetic spectrum. Utilization of ultra-wideband signals in this EHF band is of interest, since it covers a relatively large spectrum, which is free of users, resulting in better resolution in both the longitudinal and transverse dimensions. Noting that frequencies in the millimeter band are subjected to high atmospheric attenuation and dispersion effects, a study of the degradation in the accuracy and resolution is presented. The fact that solid-state millimeter and sub-millimeter radiation sources are producing low power, the method of continuous-wave wideband frequency modulation becomes the natural technique for remote sensing and detection. Millimeter wave radars are used as complementary sensors for the detection of small radar cross-section objects under bad weather conditions, when small objects cannot be seen by optical cameras and infrared detectors. Theoretical analysis for the propagation of a wide "chirped" Frequency-Modulated Continuous-Wave (FMCW) radar signal in a dielectric medium is presented. It is shown that the frequency-dependent (complex) refractivity of the atmospheric medium causes distortions in the phase of the reflected signal, introducing noticeable errors in the longitudinal distance estimations, and at some frequencies may also degrade the resolution.

Electronic DC transformer with high power density

NARCIS (Netherlands)

Pavlovský, M.

2006-01-01

This thesis is concerned with the possibilities of increasing the power density of high-power dc-dc converters with galvanic isolation. Three cornerstones for reaching high power densities are identified as: size reduction of passive components, reduction of losses particularly in active components

Research on power market technical analysis index system employing high-low matching mechanism

Science.gov (United States)

Li, Tao; Wang, Shengyu

2018-06-01

The power market trading technical analysis refers to a method that takes the bidding behavior of members in the power market as the research object, sums up some typical market rules and price trends by applying mathematical and logical methods, and finally can effectively assist members in the power market to make more reasonable trading decisions. In this paper, the following four indicators have been proposed: bidding price difference scale, extreme bidding price rate, dispersion of bidding price and monthly transaction satisfaction of electricity trading, which are the core of the index system.

Sexual aggression when power is new: Effects of acute high power on chronically low-power individuals.

Science.gov (United States)

Williams, Melissa J; Gruenfeld, Deborah H; Guillory, Lucia E

2017-02-01

Previous theorists have characterized sexually aggressive behavior as an expression of power, yet evidence that power causes sexual aggression is mixed. We hypothesize that power can indeed create opportunities for sexual aggression-but that it is those who chronically experience low power who will choose to exploit such opportunities. Here, low-power men placed in a high-power role showed the most hostility in response to a denied opportunity with an attractive woman (Studies 1 and 2). Chronically low-power men and women given acute power were the most likely to say they would inappropriately pursue an unrequited workplace attraction (Studies 3 and 4). Finally, having power over an attractive woman increased harassment behavior among men with chronic low, but not high, power (Study 5). People who see themselves as chronically denied power appear to have a stronger desire to feel powerful and are more likely to use sexual aggression toward that end. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Powerful highly efficient KrF lamps excited by surface and barrier discharges

International Nuclear Information System (INIS)

Borisov, V M; Vodchits, V A; El'tsov, A V; Khristoforov, O B

1998-01-01

An investigation was made of the characteristics of KrF lamps with different types of excitation by surface and barrier discharges in which the dielectric material was sapphire. The conditions were determined for the attainment of an extremely high yield of the KrF* fluorescence with the internal efficiency η in ∼30 % and 22% for pulsed surface and barrier discharges, respectively. A homogeneous surface discharge was maintained without gas circulation when the pulse repetition rate was 5 x 10 4 Hz. Quasicontinuous excitation of a surface discharge at near-atmospheric pressure made it possible to reach a KrF* fluorescence power density of about 80 W cm -3 , which was close to the limit set by the kinetics of the gaseous medium. Under prolonged excitation conditions the intensity of the UV output radiation was limited by the permissible heating of the gas to a temperature above which the operating life of the gaseous mixture containing fluorine fell steeply. This was the reason for the advantage of surface over barrier discharges: the former were characterised by a high thermal conductivity of a thin (∼0.2 mm) plasma layer on the surface of the cooled dielectric, which made it possible to construct powerful highly efficient KrF and ArF lamps emitting UV radiation of up to 1 W cm -2 intensity. (laser system components)

Induction linacs and pulsed power

International Nuclear Information System (INIS)

Caporaso, G.J.

1995-01-01

Progress in electronic power conversion technology is making possible a new class of induction linacs that can operate at extremely high repetition rates. Advances in insulator technology, pulse forming line design and switching may also lead to a new type of high current accelerator with accelerating gradients at least an order of magnitude greater than those attainable today. The evolution of the induction accelerator pulsed power system will be discussed along with some details of these emerging technologies which are at the frontiers of accelerator technology

Switching transients in high-frequency high-power converters using power MOSFET's

Science.gov (United States)

Sloane, T. H.; Owen, H. A., Jr.; Wilson, T. G.

1979-01-01

The use of MOSFETs in a high-frequency high-power dc-to-dc converter is investigated. Consideration is given to the phenomena associated with the paralleling of MOSFETs and to the effect of stray circuit inductances on the converter circuit performance. Analytical relationships between various time constants during the turning-on and turning-off intervals are derived which provide estimates of plateau and peak levels during these intervals.

High Power Electron Accelerator Prototype

CERN Document Server

Tkachenko, Vadim; Cheskidov, Vladimir; Korobeynikov, G I; Kuznetsov, Gennady I; Lukin, A N; Makarov, Ivan; Ostreiko, Gennady; Panfilov, Alexander; Sidorov, Alexey; Tarnetsky, Vladimir V; Tiunov, Michael A

2005-01-01

In recent time the new powerful industrial electron accelerators appear on market. It caused the increased interest to radiation technologies using high energy X-rays due to their high penetration ability. However, because of low efficiency of X-ray conversion for electrons with energy below 5 MeV, the intensity of X-rays required for some industrial applications can be achieved only when the beam power exceeds 300 kW. The report describes a project of industrial electron accelerator ILU-12 for electron energy up to 5 MeV and beam power up to 300 kW specially designed for use in industrial applications. On the first stage of work we plan to use the existing generator designed for ILU-8 accelerator. It is realized on the GI-50A triode and provides the pulse power up to 1.5-2 MW and up to 20-30 kW of average power. In the report the basic concepts and a condition of the project for today are reflected.

High Energy Density Dielectrics for Pulsed Power Applications

National Research Council Canada - National Science Library

Wu, Richard L; Bray, Kevin R

2008-01-01

This report was developed under a SBIR contract. Aluminum oxynitride (AlON) capacitors exhibit several promising characteristics for high energy density capacitor applications in extreme environments...

Space charge dosimeters for extremely low power measurements of radiation in shipping containers

Science.gov (United States)

Britton, Jr; Charles, L [Alcoa, TN; Buckner, Mark A [Oak Ridge, TN; Hanson, Gregory R [Clinton, TN; Bryan, William L [Knoxville, TN

2011-04-26

Methods and apparatus are described for space charge dosimeters for extremely low power measurements of radiation in shipping containers. A method includes in situ polling a suite of passive integrating ionizing radiation sensors including reading-out dosimetric data from a first passive integrating ionizing radiation sensor and a second passive integrating ionizing radiation sensor, where the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor remain situated where the dosimetric data was integrated while reading-out. Another method includes arranging a plurality of ionizing radiation sensors in a spatially dispersed array; determining a relative position of each of the plurality of ionizing radiation sensors to define a volume of interest; collecting ionizing radiation data from at least a subset of the plurality of ionizing radiation sensors; and triggering an alarm condition when a dose level of an ionizing radiation source is calculated to exceed a threshold.

Resonant High Power Combiners

CERN Document Server

Langlois, Michel; Peillex-Delphe, Guy

2005-01-01

Particle accelerators need radio frequency sources. Above 300 MHz, the amplifiers mostly used high power klystrons developed for this sole purpose. As for military equipment, users are drawn to buy "off the shelf" components rather than dedicated devices. IOTs have replaced most klystrons in TV transmitters and find their way in particle accelerators. They are less bulky, easier to replace, more efficient at reduced power. They are also far less powerful. What is the benefit of very compact sources if huge 3 dB couplers are needed to combine the power? To alleviate this drawback, we investigated a resonant combiner, operating in TM010 mode, able to combine 3 to 5 IOTs. Our IOTs being able to deliver 80 kW C.W. apiece, combined power would reach 400 kW minus the minor insertion loss. Values for matching and insertion loss are given. The behavior of the system in case of IOT failure is analyzed.

High Average Power, High Energy Short Pulse Fiber Laser System

Energy Technology Data Exchange (ETDEWEB)

Messerly, M J

2007-11-13

Recently continuous wave fiber laser systems with output powers in excess of 500W with good beam quality have been demonstrated [1]. High energy, ultrafast, chirped pulsed fiber laser systems have achieved record output energies of 1mJ [2]. However, these high-energy systems have not been scaled beyond a few watts of average output power. Fiber laser systems are attractive for many applications because they offer the promise of high efficiency, compact, robust systems that are turn key. Applications such as cutting, drilling and materials processing, front end systems for high energy pulsed lasers (such as petawatts) and laser based sources of high spatial coherence, high flux x-rays all require high energy short pulses and two of the three of these applications also require high average power. The challenge in creating a high energy chirped pulse fiber laser system is to find a way to scale the output energy while avoiding nonlinear effects and maintaining good beam quality in the amplifier fiber. To this end, our 3-year LDRD program sought to demonstrate a high energy, high average power fiber laser system. This work included exploring designs of large mode area optical fiber amplifiers for high energy systems as well as understanding the issues associated chirped pulse amplification in optical fiber amplifier systems.

Power Constrained High-Level Synthesis of Battery Powered Digital Systems

DEFF Research Database (Denmark)

Nielsen, Sune Fallgaard; Madsen, Jan

2003-01-01

We present a high-level synthesis algorithm solving the combined scheduling, allocation and binding problem minimizing area under both latency and maximum power per clock-cycle constraints. Our approach eliminates the large power spikes, resulting in an increased battery lifetime, a property...... of utmost importance for battery powered embedded systems. Our approach extends the partial-clique partitioning algorithm by introducing power awareness through a heuristic algorithm which bounds the design space to those of power feasible schedules. We have applied our algorithm on a set of dataflow graphs...

High stability, high current DC-power supplies

International Nuclear Information System (INIS)

Hosono, K.; Hatanaka, K.; Itahashi, T.

1995-01-01

Improvements of the power supplies and the control system of the AVF cyclotron which is used as an injector to the ring cyclotron and of the transport system to the ring cyclotron were done in order to get more high quality and more stable beam. The power supply of the main coil of the AVF cyclotron was exchanged to new one. The old DCCTs (zero-flux current transformers) used for the power supplies of the trim coils of the AVF cyclotron were changed to new DCCTs to get more stability. The potentiometers used for the reference voltages in the other power supplies of the AVF cyclotron and the transport system were changed to the temperature controlled DAC method for numerical-value settings. This paper presents the results of the improvements. (author)

An Extreme Degree of Difficulty: The Educational Demographics of Urban Neighborhood High Schools

Science.gov (United States)

Neild, Ruth Curran; Balfanz, Robert

2006-01-01

Despite the growth of a variety of alternatives to the neighborhood high school, most students in big-city school systems still attend large comprehensive high schools that serve a particular residential area. The authors contend that the extreme concentration of educational need at these schools is often overlooked by policymakers, school reform…

Tests Of A Stirling-Engine Power Converter

Science.gov (United States)

Dochat, George

1995-01-01

Report describes acceptance tests of power converter consisting of pair of opposed free-piston Stirling engines driving linear alternators. Stirling engines offer potential for extremely long life, high reliability, high efficiency at low hot-to-cold temperature ratios, and relatively low heater-head temperatures.

Automated System Tests High-Power MOSFET's

Science.gov (United States)

Huston, Steven W.; Wendt, Isabel O.

1994-01-01

Computer-controlled system tests metal-oxide/semiconductor field-effect transistors (MOSFET's) at high voltages and currents. Measures seven parameters characterizing performance of MOSFET, with view toward obtaining early indication MOSFET defective. Use of test system prior to installation of power MOSFET in high-power circuit saves time and money.

The extreme condition analyzing for NEMPI shielding of electronic system in high-intensity pulsed radiation diagnosing

International Nuclear Information System (INIS)

Cheng Xiaolei; Liu Fang; Ouyang Xiaoping

2012-01-01

The difficulty for estimating the NEMPI (electromagnetic pulsed interference caused by the nuclear reaction) on the electronic system in high-intensity pulsed radiation diagnosing is analyzed in this article. To solve the difficulty, a method called 'Extreme Condition Analyzing' is presented for estimating the NEMPI conservatively and reliably. Through an extreme condition hypothesizing which could be described as 'Entire Coupling of Electric Field Energy', the E max (maximum electric field intensity which could be endured by the electronic system in the high-intensity pulsed radiation) could be figured out without any other information of the EMP caused by the nuclear reaction. Then a feasibility inspection is introduced, to confirm that the EMPI shielding request according to E max is not too extreme to be achieved. (authors)

Adjuvant radiotherapy in high-grade extremity sarcomas

International Nuclear Information System (INIS)

Franca, Carlos Antonio da Silva; Penna, Antonio Belmiro Rodrigues Campbell; Carvalho, Antonio Carlos Pires; Vieira, Sergio Lannes

2010-01-01

Objective: to evaluate the therapies utilized in the authors' institution for management of high-grade extremity sarcomas, analyzing the overall survival rates following multidisciplinary treatment. Materials and methods: retrospective study developed in the period from 1993 to 2007 with 36 patients diagnosed with stages IIb/III, submitted to postoperative external beam radiotherapy, with or without boost dose, utilizing high-dose brachytherapy. Results: thirty-six patients underwent surgery followed by adjuvant external beam radiation therapy. Four patients (11%) received boost dose with brachytherapy, and seven (19%) received chemotherapy. The average dose for radiotherapy was 50 Gy (CI 95%: 47-53 Gy), and the four patients with brachytherapy boost received doses ranging from 16.2 to 35 Gy. Chemotherapy was indicated for seven patients (19%) with positive margins. Fifteen patients (42%) presented local or distant recurrence, and all of them progressed to death. Twenty-one patients (58%) remain with no clinical/radiological evidence of local/distant recurrence. The mean follow-up time was 88 months (IC 95%: 74-102). The overall seven years survival rate was 80%. Conclusion: combined surgery and radiotherapy is an effective treatment with excellent outcomes in cases where brachytherapy is associated, with improved overall survival rates. (author)

A Fiducial Approach to Extremes and Multiple Comparisons

Science.gov (United States)

Wandler, Damian V.

2010-01-01

Generalized fiducial inference is a powerful tool for many difficult problems. Based on an extension of R. A. Fisher's work, we used generalized fiducial inference for two extreme value problems and a multiple comparison procedure. The first extreme value problem is dealing with the generalized Pareto distribution. The generalized Pareto…

Highly-stabilized power supply for synchrotron accelerators. High speed, low ripple power supply

Energy Technology Data Exchange (ETDEWEB)

Sato, Kenji [Osaka Univ., Ibaraki (Japan). Research Center for Nuclear Physics; Kumada, Masayuki; Fukami, Kenji; Koseki, Shoichiro; Kubo, Hiroshi; Kanazawa, Toru

1997-02-01

In synchrotron accelerators, in order to utilize high energy beam effectively, those are operated by repeating acceleration and taking-out at short period. In order to accelerate by maintaining beam track stable, the tracking performance with the error less than 10{sup -3} in the follow-up of current is required for the power supply. Further, in order to maintain the intensity and uniformity of beam when it is taken out, very low ripple is required for output current. The power supply having such characteristics has been developed, and applied to the HIMAC and the SPring-8. As the examples of the application of synchrotrons, the accelerators for medical treatment and the generation of synchrotron radiation are described. As to the power supply for the deflection magnets and quadrupole magnets of synchrotron accelerators, the specifications of the main power supply, the method of reducing ripple, the method of improving tracking, and active filter control are reported. As to the test results, the measurement of current ripple and tracking error is shown. The lowering of ripple was enabled by common mode filter and the symmetrical connection of electromagnets, and high speed response was realized by the compensation for delay with active filter. (K.I.)

Mitigating the Long term Operating Extreme Load through Active Control

International Nuclear Information System (INIS)

Koukoura, Christina; Natarajan, Anand

2014-01-01

The parameters influencing the long term extreme operating design loads are identified through the implementation of a Design of Experiment (DOE) method. A function between the identified critical factors and the ultimate out-of-plane loads on the blade is determined. Variations in the initial blade azimuth location are shown to affect the extreme blade load magnitude during operation in normal turbulence wind input. The simultaneously controlled operation of generator torque variation and pitch variation at low blade pitch angles is detected to be responsible for very high loads acting on the blades. Through gain scheduling of the controller (modifications of the proportional Kp and the integral K gains) the extreme loads are mitigated, ensuring minimum instantaneous variations in the power production for operation above rated wind speed. The response of the blade load is examined for different values of the integral gain as resulting in rotor speed error and the rate of change of rotor speed. Based on the results a new load case for the simulation of extreme loads during normal operation is also presented

Reactor G1: high power experiments

International Nuclear Information System (INIS)

Laage, F. de; Teste du Baillet, A.; Veyssiere, A.; Wanner, G.

1957-01-01

The experiments carried out in the starting-up programme of the reactor G1 comprised a series of tests at high power, which allowed the following points to be studied: 1- Effect of poisoning by Xenon (absolute value, evolution). 2- Temperature coefficients of the uranium and graphite for a temperature distribution corresponding to heating by fission. 3- Effect of the pressure (due to the coiling system) on the reactivity. 4- Calibration of the security rods as a function of their position in the pile (1). 5- Temperature distribution of the graphite, the sheathing, the uranium and the air leaving the canals, in a pile running normally at high power. 6- Neutron flux distribution in a pile running normally at high power. 7- Determination of the power by nuclear and thermodynamic methods. These experiments have been carried out under two very different pile conditions. From the 1. to the 15. of August 1956, a series of power increases, followed by periods of stabilisation, were induced in a pile containing uranium only, in 457 canals, amounting to about 34 tons of fuel. A knowledge of the efficiency of the control rods in such a pile has made it possible to measure with good accuracy the principal effects at high temperatures, that is, to deal with points 1, 2, 3, 5. Flux charts giving information on the variations of the material Laplacian and extrapolation lengths in the reflector have been drawn up. Finally the thermodynamic power has been measured under good conditions, in spite of some installation difficulties. On September 16, the pile had its final charge of 100 tons. All the canals were loaded, 1,234 with uranium and 53 (i.e. exactly 4 per cent of the total number) with thorium uniformly distributed in a square lattice of 100 cm side. Since technical difficulties prevented the calibration of the control rods, the measurements were limited to the determination of the thermodynamic power and the temperature distributions (points 5 and 7). This report will

Voltage generators of high voltage high power accelerators

International Nuclear Information System (INIS)

Svinin, M.P.

1981-01-01

High voltage electron accelerators are widely used in modern radiation installations for industrial purposes. In the near future further increasing of their power may be effected, which enables to raise the efficiency of the radiation processes known and to master new power-consuming production in industry. Improvement of HV generators by increasing their power and efficiency is one of many scientific and engineering aspects the successful solution of which provides further development of these accelerators and their technical parameters. The subject is discussed in detail. (author)

Optimal Operation of Plug-In Electric Vehicles in Power Systems with High Wind Power Penetrations

DEFF Research Database (Denmark)

Hu, Weihao; Su, Chi; Chen, Zhe

2013-01-01

in the power systems with high wind power penetrations. In this paper, the integration of plug-in electric vehicles in the power systems with high wind power penetrations is proposed and discussed. Optimal operation strategies of PEV in the spot market are proposed in order to decrease the energy cost for PEV......The Danish power system has a large penetration of wind power. The wind fluctuation causes a high variation in the power generation, which must be balanced by other sources. The battery storage based Plug-In Electric Vehicles (PEV) may be a possible solution to balance the wind power variations...... owners. Furthermore, the application of battery storage based aggregated PEV is analyzed as a regulation services provider in the power system with high wind power penetrations. The western Danish power system where the total share of annual wind power production is more than 27% of the electrical energy...

Research & Implementation of AC - DC Converter with High Power Factor & High Efficiency

Directory of Open Access Journals (Sweden)

Hsiou-Hsian Nien

2014-05-01

Full Text Available In this paper, we design and develop a high power factor, high efficiency two-stage AC - DC power converter. This paper proposes a two-stage AC - DC power converter. The first stage is boost active power factor correction circuit. The latter stage is near constant frequency LLC resonant converter. In addition to traditional LLC high efficiency advantages, light-load conversion efficiency of this power converter can be improved. And it possesses high power factor and near constant frequency operating characteristics, can significantly reduce the electromagnetic interference. This paper first discusses the main structure and control manner of power factor correction circuit. And then by the LLC resonant converter equivalent model proceed to circuit analysis to determine the important parameters of the converter circuit elements. Then design a variable frequency resonant tank. The resonant frequency can change automatically on the basis of the load to reach near constant frequency operation and a purpose of high efficiency. Finally, actually design and produce an AC – DC power converter with output of 190W to verify the characteristics and feasibility of this converter. The experimental results show that in a very light load (9.5 W the efficiency is as high as 81%, the highest efficiency of 88% (90 W. Full load efficiency is 87%. At 19 W ~ 190 W power changes, the operating frequency change is only 0.4 kHz (AC 110 V and 0.3 kHz (AC 220 V.

High-Bandwidth, High-Efficiency Envelope Tracking Power Supply for 40W RF Power Amplifier Using Paralleled Bandpass Current Sources

DEFF Research Database (Denmark)

Høyerby, Mikkel Christian Wendelboe; Andersen, Michael Andreas E.

2005-01-01

This paper presents a high-performance power conversion scheme for power supply applications that require very high output voltage slew rates (dV/dt). The concept is to parallel 2 switching bandpass current sources, each optimized for its passband frequency space and the expected load current....... The principle is demonstrated with a power supply, designed for supplying a 40 W linear RF power amplifier for efficient amplification of a 16-QAM modulated data stream...

Small high cooling power space cooler

Energy Technology Data Exchange (ETDEWEB)

Nguyen, T. V.; Raab, J.; Durand, D.; Tward, E. [Northrop Grumman Aerospace Systems Redondo Beach, Ca, 90278 (United States)

2014-01-29

The small High Efficiency pulse tube Cooler (HEC) cooler, that has been produced and flown on a number of space infrared instruments, was originally designed to provide cooling of 10 W @ 95 K. It achieved its goal with >50% margin when limited by the 180 W output ac power of its flight electronics. It has also been produced in 2 stage configurations, typically for simultaneously cooling of focal planes to temperatures as low as 35 K and optics at higher temperatures. The need for even higher cooling power in such a low mass cryocooler is motivated by the advent of large focal plane arrays. With the current availability at NGAS of much larger power cryocooler flight electronics, reliable long term operation in space with much larger cooling powers is now possible with the flight proven 4 kg HEC mechanical cooler. Even though the single stage cooler design can be re-qualified for those larger input powers without design change, we redesigned both the linear and coaxial version passive pulse tube cold heads to re-optimize them for high power cooling at temperatures above 130 K while rejecting heat to 300 K. Small changes to the regenerator packing, the re-optimization of the tuned inertance and no change to the compressor resulted in the increased performance at 150 K. The cooler operating at 290 W input power achieves 35 W@ 150 K corresponding to a specific cooling power at 150 K of 8.25 W/W and a very high specific power of 72.5 W/Kg. At these powers the cooler still maintains large stroke, thermal and current margins. In this paper we will present the measured data and the changes to this flight proven cooler that were made to achieve this increased performance.

Gate Drive For High Speed, High Power IGBTs

Energy Technology Data Exchange (ETDEWEB)

Nguyen, M.N.; Cassel, R.L.; de Lamare, J.E.; Pappas, G.C.; /SLAC

2007-06-18

A new gate drive for high-voltage, high-power IGBTs has been developed for the SLAC NLC (Next Linear Collider) Solid State Induction Modulator. This paper describes the design and implementation of a driver that allows an IGBT module rated at 800A/3300V to switch up to 3000A at 2200V in 3{micro}S with a rate of current rise of more than 10000A/{micro}S, while still being short circuit protected. Issues regarding fast turn on, high de-saturation voltage detection, and low short circuit peak current will be presented. A novel approach is also used to counter the effect of unequal current sharing between parallel chips inside most high-power IGBT modules. It effectively reduces the collector-emitter peak current, and thus protects the IGBT from being destroyed during soft short circuit conditions at high di/dt.

Gate Drive For High Speed, High Power IGBTs

International Nuclear Information System (INIS)

Nguyen, M.N.; Cassel, R.L.; de Lamare, J.E.; Pappas, G.C.; SLAC

2007-01-01

A new gate drive for high-voltage, high-power IGBTs has been developed for the SLAC NLC (Next Linear Collider) Solid State Induction Modulator. This paper describes the design and implementation of a driver that allows an IGBT module rated at 800A/3300V to switch up to 3000A at 2200V in 3(micro)S with a rate of current rise of more than 10000A/(micro)S, while still being short circuit protected. Issues regarding fast turn on, high de-saturation voltage detection, and low short circuit peak current will be presented. A novel approach is also used to counter the effect of unequal current sharing between parallel chips inside most high-power IGBT modules. It effectively reduces the collector-emitter peak current, and thus protects the IGBT from being destroyed during soft short circuit conditions at high di/dt

Preconditioned iterations to calculate extreme eigenvalues

Energy Technology Data Exchange (ETDEWEB)

Brand, C.W.; Petrova, S. [Institut fuer Angewandte Mathematik, Leoben (Austria)

1994-12-31

Common iterative algorithms to calculate a few extreme eigenvalues of a large, sparse matrix are Lanczos methods or power iterations. They converge at a rate proportional to the separation of the extreme eigenvalues from the rest of the spectrum. Appropriate preconditioning improves the separation of the eigenvalues. Davidson`s method and its generalizations exploit this fact. The authors examine a preconditioned iteration that resembles a truncated version of Davidson`s method with a different preconditioning strategy.

High dose rate brachytherapy for the treatment of soft tissue sarcoma of the extremity

International Nuclear Information System (INIS)

Speight, J.L.; Streeter, O.E.; Chawla, S.; Menendez, L.E.

1996-01-01

Purpose: we examined the role of preoperative neoadjuvant chemoradiation and adjuvant high-dose rate brachytherapy on the management of prognostically unfavorable soft tissue sarcomas of the extremities. Our goal was to examine the effect of high dose rate interstitial brachytherapy (HDR IBT) on reducing the risk of local recurrence following limb-sparing resection, as well as shortening treatment duration. Materials and methods: eleven patients, ranging in age from 31 to 73 years old, with soft tissue sarcoma of the extremity were treated at USC/Norris Comprehensive Cancer Center during 1994 and 1995. All patients had biopsy proven soft tissue sarcoma, and all were suitable candidates for limb-sparing surgery. All lesions were greater than 5cm in size and were primarily high grade. Tumor histologies included malignant fibrous histiocytoma (45%), liposarcoma (18%) and leiomyosarcoma, synovial cell sarcoma and spindle cell sarcoma (36%). Sites of tumor origin were the lower extremity (55%), upper extremity (18%) and buttock (9%), 1 patient (9%) had lesions in both the upper and lower extremity. Patients received HDR IBT following combined chemotherapy and external beam irradiation (EBRT) and en bloc resection of the sarcoma. Neoadjuvant chemotherapy consisted of three to four cycles of either Ifosfamide/Mesna with or without Adriamycin, or Mesna, Adriamycin, Ifosfamide and Dacarbazine. One patient received Cis-platin in addition to Ifos/Adr. A minimum of two cycles of chemotherapy were administered prior to EBRT. Additional cycles of chemotherapy were completed concurrently with EBRT but prior to HDR IBT. Preoperative EBRT doses ranging from 40 to 59.4 Gy were given in daily fractions of 180 to 200cGy. Following en bloc resection, HDR IBT was administered using the Omnitron tm 2000 remote afterloading system. Doses ranging from 13 to 30 Gy were delivered to the surgical tumor bed at depths of 0.5mm to 0.75mm from the radioactive source. Results: median follow-up was

Overview on the high power excimer laser technology

Science.gov (United States)

Liu, Jingru

2013-05-01

High power excimer laser has essential applications in the fields of high energy density physics, inertial fusion energy and industry owing to its advantages such as short wavelength, high gain, wide bandwidth, energy scalable and repetition operating ability. This overview is aimed at an introduction and evaluation of enormous endeavor of the international high power excimer laser community in the last 30 years. The main technologies of high power excimer laser are reviewed, which include the pumping source technology, angular multiplexing and pulse compressing, beam-smoothing and homogenous irradiation, high efficiency and repetitive operation et al. A high power XeCl laser system developed in NINT of China is described in detail.

Integrated nanomaterials for extreme thermal management: a perspective for aerospace applications.

Science.gov (United States)

Barako, Michael T; Gambin, Vincent; Tice, Jesse

2018-04-02

Nanomaterials will play a disruptive role in next-generation thermal management for high power electronics in aerospace platforms. These high power and high frequency devices have been experiencing a paradigm shift toward designs that favor extreme integration and compaction. The reduction in form factor amplifies the intensity of the thermal loads and imposes extreme requirements on the thermal management architecture for reliable operation. In this perspective, we introduce the opportunities and challenges enabled by rationally integrating nanomaterials along the entire thermal resistance chain, beginning at the high heat flux source up to the system-level heat rejection. Using gallium nitride radio frequency devices as a case study, we employ a combination of viewpoints comprised of original research, academic literature, and industry adoption of emerging nanotechnologies being used to construct advanced thermal management architectures. We consider the benefits and challenges for nanomaterials along the entire thermal pathway from synthetic diamond and on-chip microfluidics at the heat source to vertically-aligned copper nanowires and nanoporous media along the heat rejection pathway. We then propose a vision for a materials-by-design approach to the rational engineering of complex nanostructures to achieve tunable property combinations on demand. These strategies offer a snapshot of the opportunities enabled by the rational design of nanomaterials to mitigate thermal constraints and approach the limits of performance in complex aerospace electronics.

Integrated nanomaterials for extreme thermal management: a perspective for aerospace applications

Science.gov (United States)

Barako, Michael T.; Gambin, Vincent; Tice, Jesse

2018-04-01

Nanomaterials will play a disruptive role in next-generation thermal management for high power electronics in aerospace platforms. These high power and high frequency devices have been experiencing a paradigm shift toward designs that favor extreme integration and compaction. The reduction in form factor amplifies the intensity of the thermal loads and imposes extreme requirements on the thermal management architecture for reliable operation. In this perspective, we introduce the opportunities and challenges enabled by rationally integrating nanomaterials along the entire thermal resistance chain, beginning at the high heat flux source up to the system-level heat rejection. Using gallium nitride radio frequency devices as a case study, we employ a combination of viewpoints comprised of original research, academic literature, and industry adoption of emerging nanotechnologies being used to construct advanced thermal management architectures. We consider the benefits and challenges for nanomaterials along the entire thermal pathway from synthetic diamond and on-chip microfluidics at the heat source to vertically-aligned copper nanowires and nanoporous media along the heat rejection pathway. We then propose a vision for a materials-by-design approach to the rational engineering of complex nanostructures to achieve tunable property combinations on demand. These strategies offer a snapshot of the opportunities enabled by the rational design of nanomaterials to mitigate thermal constraints and approach the limits of performance in complex aerospace electronics.

Extreme-ultraviolet wavelength and lifetime measurements in highly ionized krypton

CERN Document Server

Kukla, K W; Vogt, C M V; Berry, H G; Dunford, R W; Curtis, L J; Cheng, S

2005-01-01

We have studied the spectrum of highly ionized krypton in the extreme-ultraviolet wavelength region (50-300 Aa), using beam-foil excitation of fast krypton ions at the Argonne ATLAS accelerator facility. We report measurements of transition wavelengths and excited-state lifetimes for n=2 states in the lithiumlike, berylliumlike, and boronlike ions, Kr/sup 31+,32+,33+/. Excited state lifetimes ranging from 10 ps to 3 ns were measured by acquiring time- of-flight-delayed spectra with a position-sensitive multichannel detector.

High Power Fiber Laser Test Bed

Data.gov (United States)

Federal Laboratory Consortium — This facility, unique within DoD, power-combines numerous cutting-edge fiber-coupled laser diode modules (FCLDM) to integrate pumping of high power rare earth-doped...

Study of a pressure measurement method using laser ionization for extremely-high vacuum

International Nuclear Information System (INIS)

Kokubun, Kiyohide

1991-01-01

A method of measuring pressures in the range of extremely-high vacuum (XHV) using the laser ionization has been studied. For this purpose, nonresonant multiphoton ionization of various kinds of gases has been studied, and highly-sensitive ion-detection systems and an extremely-high vacuum equipment were fabricated. These results are presented in detail. Two ion-detection systems were fabricated and tested: the one is based on the pulse-counting method, and the other utilizes the image-processing technique. The former is superior in detecting a few ions or less. The latter was processing technique. The former is superior in detecting a few ions or less. The latter was verified to able to count accurately the number of ions in the range of a few to several hundreds. To obtain the information on residual gases and test our pressure measurement system, an extremely-high vacuum system was fabricated in our own fashion, attained a pressure lower than 1 x 10 -10 Pa, measured with an extractor gauge. The outgassing rate of this vacuum vessel was measured to be 7.8 x 10 -11 Pa·m 3 /s·m 2 . The surface structures and the surface compositions of the raw material, the machined material, and the machined-and-outgased material were studied by SEM and AES. Besides, the pumping characteristics and the residual gases of the XHV system were investigated in detail at each pumping stage. On the course of these studies, the method of pressure measurement using the laser-ionization has been verified to be very effective for measuring pressures in XHV. (J.P.N.)

High average-power induction linacs

International Nuclear Information System (INIS)

Prono, D.S.; Barrett, D.; Bowles, E.

1989-01-01

Induction linear accelerators (LIAs) are inherently capable of accelerating several thousand amperes of /approximately/ 50-ns duration pulses to > 100 MeV. In this paper we report progress and status in the areas of duty factor and stray power management. These technologies are vital if LIAs are to attain high average power operation. 13 figs

Development of a high-resolution apparatus to monitor physiological state of a person undergoing extreme conditions

Directory of Open Access Journals (Sweden)

Kodermyatov Radik

2016-01-01

Full Text Available The present research has shown that ECG recordings and parameters of the body functional state are crucial for all kinds of the astronaut pre-flight preparations (centrifuge, thermal chamber, pressure chamber, pressure chamber with special equipment. It is, therefore, important to develop methods and tools for early detection of the preclinical forms of the functional state disorders in patients undergoing high-intensity loads of mixed character. The method based on the hardware-software compleх (HSC with nanosensors of high resolution has been proposed to measure the electrophysiological characteristics and bioelectrical impedance of the body tissues directly exposed to loading. The hardware-software compleх is subjected to clinical trials in Tomsk Research Institute for Cardiology. The obtained results show that the use of nanosensors of high resolution in the HSC without standard filters allows elimination of the power-line interference in ECG recordings. Monitoring of the tissue bioimpedance parameters under test loads enables the detection of preclinical (latent forms of various diseases. After clinical trials in Tomsk Institute for Cardiology the developed apparatus will be proposed for in-depth study of the cardiovascular system and the functional state of the body of astronauts and other persons exposed to extreme loads.

Spectroscopy of Molecules in Extreme Rotational States Using AN Optical Centrifuge

Science.gov (United States)

Mullin, Amy S.; Toro, Carlos; Echibiri, Geraldine; Liu, Qingnan

2012-06-01

Our lab has developed a high-power optical centrifuge that is capable of trapping and spinning large number densities of molecules into extreme rotational states. By coupling this device with high resolution transient IR absorption spectroscopy, we measure the time-resolved behavior and energy profiles of individual ro-vibrational states of molecules in very high rotational states. Recent results will be discussed on the spectroscopy of new rotational states, collisional dynamics in the optical centrifuge, spatially-dependent energy profiles and possibilities for new chemistry induced by centrifugal forces.

Design of The High Efficiency Power Factor Correction Circuit for Power Supply

Directory of Open Access Journals (Sweden)

Atiye Hülya OBDAN

2017-12-01

Full Text Available Designing power factor correction circuits for switched power supplies has become important in recent years in terms of efficient use of energy. Power factor correction techniques play a significant role in high power density and energy efficiency. For these purposes, bridgeless PFC topologies and control strategies have been developed alongside basic boost PFC circuits. The power density can be increased using bridgeless structures by means of reducing losses in the circuit. This article examines bridgeless PFC structures and compares their performances in terms of losses and power factor. A semi-bridgeless PFC, which is widely used at high power levels, was analyzed and simulated. The designed circuit simulation using the current mode control method was performed in the PSIM program. A prototype of a 900 W semi-bridgeless PFC circuit was implemented and the results obtained from the circuit are presented

Highly Reliable Power and Communication System for Essential Instruments under a Severe Accident of NPPs

Energy Technology Data Exchange (ETDEWEB)

Yoo, S. J.; Choi, B. H.; Jung, S. Y.; Rim, Chun T. [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

2013-10-15

In this paper, three survivable strategies to overcome the problems listed above are proposed for the essential instruments under the severe accident of NPPs. First, wire/wireless multi power systems are adopted to the essential instruments for continuous power supply. Second, wire/wireless communication systems are proposed for reliable transmission of measuring information among instruments and operators. Third, a physical protection system such as a harness and a heat isolation box is introduced to ensure operable conditions for the proposed systems. In this paper, a highly reliable strategy, which consists of wire/wireless multi power and communication systems and physical protection system is proposed to ensure the survival of the essential instruments under harsh external conditions. The wire/wireless multi power and communication systems are designed to transfer power and data in spite of the failure of conventional wired systems. The physical protection system provides operable environments to the instruments. Therefore, the proposed system can be considered as a candidate of practical and urgent remedy for NPPs under the severe accident. After the Fukushima nuclear accident, survivability of essential instruments has been emphasized for immediate and accurate response. The essential instruments can measure environment conditions such as temperature, pressure, radioactivity and corium behavior inside nuclear power plants (NPPs) under a severe accident. Access to the inside of NPPs is restricted to human beings because of hazardous environment such as high radioactivity, high temperature and high pressure. Thus, monitoring the inside of NPPs is necessary for avoiding damage from the severe accident. Even though there were a number of instruments in Fukushima Daiichi NPP, they failed to obtain exact monitoring information. According to the details of the Fukushima nuclear accident, following problems can be counted as strong candidates of this instruments

Highly Reliable Power and Communication System for Essential Instruments under a Severe Accident of NPPs

International Nuclear Information System (INIS)

Yoo, S. J.; Choi, B. H.; Jung, S. Y.; Rim, Chun T.

2013-01-01

In this paper, three survivable strategies to overcome the problems listed above are proposed for the essential instruments under the severe accident of NPPs. First, wire/wireless multi power systems are adopted to the essential instruments for continuous power supply. Second, wire/wireless communication systems are proposed for reliable transmission of measuring information among instruments and operators. Third, a physical protection system such as a harness and a heat isolation box is introduced to ensure operable conditions for the proposed systems. In this paper, a highly reliable strategy, which consists of wire/wireless multi power and communication systems and physical protection system is proposed to ensure the survival of the essential instruments under harsh external conditions. The wire/wireless multi power and communication systems are designed to transfer power and data in spite of the failure of conventional wired systems. The physical protection system provides operable environments to the instruments. Therefore, the proposed system can be considered as a candidate of practical and urgent remedy for NPPs under the severe accident. After the Fukushima nuclear accident, survivability of essential instruments has been emphasized for immediate and accurate response. The essential instruments can measure environment conditions such as temperature, pressure, radioactivity and corium behavior inside nuclear power plants (NPPs) under a severe accident. Access to the inside of NPPs is restricted to human beings because of hazardous environment such as high radioactivity, high temperature and high pressure. Thus, monitoring the inside of NPPs is necessary for avoiding damage from the severe accident. Even though there were a number of instruments in Fukushima Daiichi NPP, they failed to obtain exact monitoring information. According to the details of the Fukushima nuclear accident, following problems can be counted as strong candidates of this instruments

A high frequency, high power CARM proposal for the DEMO ECRH system

International Nuclear Information System (INIS)

Mirizzi, Francesco; Spassovsky, Ivan; Ceccuzzi, Silvio; Dattoli, Giuseppe; Di Palma, Emanuele; Doria, Andrea; Gallerano, Gianpiero; Lampasi, Alessandro; Maffia, Giuseppe; Ravera, GianLuca; Sabia, Elio; Tuccillo, Angelo Antonio; Zito, Pietro

2015-01-01

Highlights: • ECRH system for DEMO. • Cyclotron Auto-Resonance Maser (CARM) devices. • Relativistic electron beams. • Bragg reflectors. • High voltage pulse modulators. - Abstract: ECRH&CD systems are extensively used on tokamak plasmas due to their capability of highly tailored power deposition, allowing very localised heating and non-inductive current drive, useful for MHD and profiles control. The high electron temperatures expected in DEMO will require ECRH systems with operating frequency in the 200–300 GHz range, equipped with a reasonable number of high power (P ≥ 1 MW) CW RF sources, for allowing central RF power deposition. In this frame the ENEA Fusion Department (Frascati) is coordinating a task force aimed at the study and realisation of a suitable high power, high frequency reliable source.

A high frequency, high power CARM proposal for the DEMO ECRH system

Energy Technology Data Exchange (ETDEWEB)

Mirizzi, Francesco, E-mail: francesco.mirizzi@enea.it [Consorzio CREATE, Via Claudio 21, I-80125 Napoli (Italy); Spassovsky, Ivan [Unità Tecnica Applicazioni delle Radiazioni – ENEA, C.R. Frascati, via E. Fermi 45, I-00044 Frascati (Italy); Ceccuzzi, Silvio [Unità Tecnica Fusione – ENEA C. R. Frascati, via E. Fermi 45, 00044 Frascati, Roma (Italy); Dattoli, Giuseppe; Di Palma, Emanuele; Doria, Andrea; Gallerano, Gianpiero [Unità Tecnica Applicazioni delle Radiazioni – ENEA, C.R. Frascati, via E. Fermi 45, I-00044 Frascati (Italy); Lampasi, Alessandro; Maffia, Giuseppe; Ravera, GianLuca [Unità Tecnica Fusione – ENEA C. R. Frascati, via E. Fermi 45, 00044 Frascati, Roma (Italy); Sabia, Elio [Unità Tecnica Applicazioni delle Radiazioni – ENEA, C.R. Frascati, via E. Fermi 45, I-00044 Frascati (Italy); Tuccillo, Angelo Antonio; Zito, Pietro [Unità Tecnica Fusione – ENEA C. R. Frascati, via E. Fermi 45, 00044 Frascati, Roma (Italy)

2015-10-15

Highlights: • ECRH system for DEMO. • Cyclotron Auto-Resonance Maser (CARM) devices. • Relativistic electron beams. • Bragg reflectors. • High voltage pulse modulators. - Abstract: ECRH&CD systems are extensively used on tokamak plasmas due to their capability of highly tailored power deposition, allowing very localised heating and non-inductive current drive, useful for MHD and profiles control. The high electron temperatures expected in DEMO will require ECRH systems with operating frequency in the 200–300 GHz range, equipped with a reasonable number of high power (P ≥ 1 MW) CW RF sources, for allowing central RF power deposition. In this frame the ENEA Fusion Department (Frascati) is coordinating a task force aimed at the study and realisation of a suitable high power, high frequency reliable source.

High average-power induction linacs

International Nuclear Information System (INIS)

Prono, D.S.; Barrett, D.; Bowles, E.; Caporaso, G.J.; Chen, Yu-Jiuan; Clark, J.C.; Coffield, F.; Newton, M.A.; Nexsen, W.; Ravenscroft, D.; Turner, W.C.; Watson, J.A.

1989-01-01

Induction linear accelerators (LIAs) are inherently capable of accelerating several thousand amperes of ∼ 50-ns duration pulses to > 100 MeV. In this paper the authors report progress and status in the areas of duty factor and stray power management. These technologies are vital if LIAs are to attain high average power operation. 13 figs

Multi-megawatt wind-power installations call for new, high-performance solutions

International Nuclear Information System (INIS)

2004-01-01

This article discusses the development of increasingly powerful and profitable wind-energy installations for off-shore, on-shore and refurbishment sites. In particular, the rapid development of megawatt-class units is discussed. The latest products of various companies with rotor diameters of up to 120 metres and with power ratings of up to 5 MW are looked at and commented on. The innovations needed for the reduction of weight and the extreme demands placed on gearing systems are discussed. Also, the growing markets for wind energy installations in Europe and the United States are discussed and plans for new off-shore wind parks are looked at

Operational experience of extreme wind penetrations

Energy Technology Data Exchange (ETDEWEB)

Estanqueiro, Ana [INETI/LNEG - National Laboratory for Energy and Geology, Lisbon (Portugal); Mateus, Carlos B. [Instituto de Meteorologia, Lisboa (Portugal); Pestana, Rui [Redes Energeticas Nacionais (REN), Lisboa (Portugal)

2010-07-01

This paper reports the operational experience from the Portuguese Power System during the 2009/2010 winter months when record wind penerations were observed: the instantaneous wind power penetration peaked at 70% of consumption during no-load periods and the wind energy accounted for more than 50% of the energy consumed for a large period. The regulation measures taken by the TSO are presented in the paper, together with the additional reserves operated for added system security. Information on the overall power system behavior under such extreme long-term wind power penetrations will also be addressed. (org.)

High power gyrotrons: a close perspective

International Nuclear Information System (INIS)

Kartikeyan, M.V.

2012-01-01

Gyrotrons and their variants, popularly known as gyrodevices are millimetric wave sources provide very high powers ranging from long pulse to continuous wave (CW) for various technological, scientific and industrial applications. From their conception (monotron-version) in the late fifties until their successful development for various applications, these devices have come a long way technologically and made an irreversible impact on both users and developers. The possible applications of high power millimeter and sub-millimeter waves from gyrotrons and their variants (gyro-devices) span a wide range of technologies. The plasma physics community has already taken advantage of the recent advances of gyrotrons in the areas of RF plasma production, heating, non-inductive current drive, plasma stabilization and active plasma diagnostics for magnetic confinement thermonuclear fusion research, such as lower hybrid current drive (LHCD) (8 GHz), electron cyclotron resonance heating (ECRH) (28-170-220 GHz), electron cyclotron current drive (ECCD), collective Thomson scattering (CTS), heat-wave propagation experiments, and space-power grid (SPG) applications. Other important applications of gyrotrons are electron cyclotron resonance (ECR) discharges for the generation of multi- charged ions and soft X-rays, as well as industrial materials processing and plasma chemistry. Submillimeter wave gyrotrons are employed in high frequency, broadband electron paramagnetic resonance (EPR) spectroscopy. Additional future applications await the development of novel high power gyro-amplifiers and devices for high resolution radar ranging and imaging in atmospheric and planetary science as well as deep space and specialized satellite communications, RF drivers for next generation high gradient linear accelerators (supercolliders), high resolution Doppler radar, radar ranging and imaging in atmospheric and planetary science, drivers for next-generation high-gradient linear accelerators

High voltage generator circuit with low power and high efficiency applied in EEPROM

International Nuclear Information System (INIS)

Liu Yan; Zhang Shilin; Zhao Yiqiang

2012-01-01

This paper presents a low power and high efficiency high voltage generator circuit embedded in electrically erasable programmable read-only memory (EEPROM). The low power is minimized by a capacitance divider circuit and a regulator circuit using the controlling clock switch technique. The high efficiency is dependent on the zero threshold voltage (V th ) MOSFET and the charge transfer switch (CTS) charge pump. The proposed high voltage generator circuit has been implemented in a 0.35 μm EEPROM CMOS process. Measured results show that the proposed high voltage generator circuit has a low power consumption of about 150.48 μW and a higher pumping efficiency (83.3%) than previously reported circuits. This high voltage generator circuit can also be widely used in low-power flash devices due to its high efficiency and low power dissipation. (semiconductor integrated circuits)

Optical Fiber for High-Power Optical Communication

Directory of Open Access Journals (Sweden)

Kenji Kurokawa

2012-09-01

Full Text Available We examined optical fibers suitable for avoiding such problems as the fiber fuse phenomenon and failures at bends with a high power input. We found that the threshold power for fiber fuse propagation in photonic crystal fiber (PCF and hole-assisted fiber (HAF can exceed 18 W, which is more than 10 times that in conventional single-mode fiber (SMF. We considered this high threshold power in PCF and HAF to be caused by a jet of high temperature fluid penetrating the air holes. We showed examples of two kinds of failures at bends in conventional SMF when the input power was 9 W. We also observed the generation of a fiber fuse under a condition that caused a bend-loss induced failure. We showed that one solution for the failures at bends is to use optical fibers with a low bending loss such as PCF and HAF. Therefore, we consider PCF and HAF to be attractive solutions to the problems of the fiber fuse phenomenon and failures at bends with a high power input.

Global patterns of NDVI-indicated vegetation extremes and their sensitivity to climate extremes

International Nuclear Information System (INIS)

Liu Guo; Liu Hongyan; Yin Yi

2013-01-01

Extremes in climate have significant impacts on ecosystems and are expected to increase under future climate change. Extremes in vegetation could capture such impacts and indicate the vulnerability of ecosystems, but currently have not received a global long-term assessment. In this study, a robust method has been developed to detect significant extremes (low values) in biweekly time series of global normalized difference vegetation index (NDVI) from 1982 to 2006 and thus to acquire a global pattern of vegetation extreme frequency. This pattern coincides with vegetation vulnerability patterns suggested by earlier studies using different methods over different time spans, indicating a consistent mechanism of regulation. Vegetation extremes were found to aggregate in Amazonia and in the semi-arid and semi-humid regions in low and middle latitudes, while they seldom occurred in high latitudes. Among the environmental variables studied, extreme low precipitation has the highest slope against extreme vegetation. For the eight biomes analyzed, these slopes are highest in temperate broadleaf forest and temperate grassland, suggesting a higher sensitivity in these environments. The results presented here contradict the hypothesis that vegetation in water-limited semi-arid and semi-humid regions might be adapted to drought and suggest that vegetation in these regions (especially temperate broadleaf forest and temperate grassland) is highly prone to vegetation extreme events under more severe precipitation extremes. It is also suggested here that more attention be paid to precipitation-induced vegetation changes than to temperature-induced events. (letter)

The AC Impedance Characteristic of High Power Li4Ti5O12-based Battery Cells

DEFF Research Database (Denmark)

Stroe, Ana-Irina; Stroe, Daniel Loan; Swierczynski, Maciej Jozef

2015-01-01

This paper studies the impedance characteristics of a fresh 13 Ah high-power lithium titanate oxide (LTO) battery cell and analyses its dependence on the temperature and state-of-charge. The impedance of the battery cell was measured by means of the electrochemical impedance spectroscopy (EIS......) technique for the entire state-of-charge (SOC) interval and considering five temperatures between 5oC and 45oC. By analyzing the measured impedance spectra of the LTO-based battery cell, it was found out that the cell’s impedance is extremely dependent on the operating conditions. By further processing...

Thermal Cycling and High Temperature Reverse Bias Testing of Control and Irradiated Gallium Nitride Power Transistors

Science.gov (United States)

Patterson, Richard L.; Boomer, Kristen T.; Scheick, Leif; Lauenstein, Jean-Marie; Casey, Megan; Hammoud, Ahmad

2014-01-01

The power systems for use in NASA space missions must work reliably under harsh conditions including radiation, thermal cycling, and exposure to extreme temperatures. Gallium nitride semiconductors show great promise, but information pertaining to their performance is scarce. Gallium nitride N-channel enhancement-mode field effect transistors made by EPC Corporation in a 2nd generation of manufacturing were exposed to radiation followed by long-term thermal cycling and testing under high temperature reverse bias conditions in order to address their reliability for use in space missions. Result of the experimental work are presented and discussed.

Workshop on High Power ICH Antenna Designs for High Density Tokamaks

Science.gov (United States)

Aamodt, R. E.

1990-02-01

A workshop in high power ICH antenna designs for high density tokamaks was held to: (1) review the data base relevant to the high power heating of high density tokamaks; (2) identify the important issues which need to be addressed in order to ensure the success of the ICRF programs on CIT and Alcator C-MOD; and (3) recommend approaches for resolving the issues in a timely realistic manner. Some specific performance goals for the antenna system define a successful design effort. Simply stated these goals are: couple the specified power per antenna into the desired ion species; produce no more than an acceptable level of RF auxiliary power induced impurities; and have a mechanical structure which safely survives the thermal, mechanical and radiation stresses in the relevant environment. These goals are intimately coupled and difficult tradeoffs between scientific and engineering constraints have to be made.

The NASA CSTI High Capacity Power Project

International Nuclear Information System (INIS)

Winter, J.; Dudenhoefer, J.; Juhasz, A.; Schwarze, G.; Patterson, R.; Ferguson, D.; Schmitz, P.; Vandersande, J.

1992-01-01

This paper describes the elements of NASA's CSTI High Capacity Power Project which include Systems Analysis, Stirling Power Conversion, Thermoelectric Power Conversion, Thermal Management, Power Management, Systems Diagnostics, Environmental Interactions, and Material/Structural Development. Technology advancement in all elements is required to provide the growth capability, high reliability and 7 to 10 year lifetime demanded for future space nuclear power systems. The overall project will develop and demonstrate the technology base required to provide a wide range of modular power systems compatible with the SP-100 reactor which facilitates operation during lunar and planetary day/night cycles as well as allowing spacecraft operation at any attitude or distance from the sun. Significant accomplishments in all of the project elements will be presented, along with revised goals and project timeliness recently developed

Upgrade of the SLAC SLED II Pulse Compression System Based on Recent High Power Tests

International Nuclear Information System (INIS)

Vlieks, A.E.; Fowkes, W.R.; Loewen, R.J.; Tantawi, S.G.

2011-01-01

In the Next Linear Collider (NLC) it is expected that the high power rf components be able to handle peak power levels in excess of 400 MW. We present recent results of high power tests designed to investigate the RF breakdown limits of the X-band pulse compression system used at SLAC. (SLED-II). Results of these tests show that both the TE 01 -TE 10 mode converter and the 4-port hybrid have a maximum useful power limit of 220-250 MW. Based on these tests, modifications of these components have been undertaken to improve their peak field handling capability. Results of these modifications will be presented. As part of an international effort to develop a new 0.5-1.5 TeV electron-positron linear collider for the 21st century, SLAC has been working towards a design, referred to as 'The Next Linear Collider' (NLC), which will operate at 11.424 GHz and utilize 50-75 MW klystrons as rf power sources. One of the major challenges in this design, or any other design, is how to generate and efficiently transport extremely high rf power from a source to an accelerator structure. SLAC has been investigating various methods of 'pulse compressing' a relatively wide rf pulse ((ge) 1 μs) from a klystron into a narrower, but more intense, pulse. Currently a SLED-II pulse compression scheme is being used at SLAC in the NLC Test Accelerator (NLCTA) and in the Accelerator Structures Test Area (ASTA) to provide high rf power for accelerator and component testing. In ASTA, a 1.05 μs pulse from a 50 MW klystron was successfully pulse compressed to 205 MW with a pulse width of 150 ns. Since operation in NLC will require generating and transporting rf power in excess of 400 MW it was decided to test the breakdown limits of the SLED-II rf components in ASTA with rf power up to the maximum available of 400 MW. This required the combining of power from two 50 MW klystrons and feeding the summed power into the SLED-II pulse compressor. Results from this experiment demonstrated that two of

Foldable Compactly Stowable Extremely High Power Solar Array System, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Deployable Space Systems, Inc. (DSS) has developed a high performance solar array system that has game-changing performance metrics in terms of ultra-compact stowage...

Characteristics of Extreme Extratropical Cyclones in a High-Resolution Global Climate Model

Science.gov (United States)

Catalano, A. J.; Broccoli, A. J.; Kapnick, S. B.; Janoski, T. P.

2017-12-01

In the northeastern United States, many of the strongest impacts from extratropical cyclones (ETCs) are associated with storms that exhibit slow movement, unusual tracks, or exceptional intensity. Examples of extreme ETCs include the Appalachian storm of November 1950, the Perfect Storm of October 1991, and the Superstorm of March 1993. Owing to the rare nature of these events, it is difficult to quantify the associated risks (e.g. high winds, storm surge) given the limited duration of high-quality observational datasets. Furthermore, storms with even greater impacts than those observed may be possible, particularly in a warming climate. In the context of tropical cyclones, Lin and Emanuel (2016) have used the metaphor "grey swans" to refer to high-impact events that have not been observed but may be physically possible. One method for analyzing "grey swans" is to generate a larger sample of ETCs using a coupled climate model. Therefore, we use long simulations (over 1,000 years with atmospheric constituents fixed at 1990 levels) from a global climate model (GFDL FLOR) with 50km atmospheric resolution. FLOR has been shown to realistically simulate the spatial distribution and climatology of ETCs during the reanalysis era. We will discuss the climatological features of these extreme ETC events.

Characterization of sp3 bond content of carbon films deposited by high power gas injection magnetron sputtering method by UV and VIS Raman spectroscopy

Science.gov (United States)

Zdunek, Krzysztof; Chodun, Rafał; Wicher, Bartosz; Nowakowska-Langier, Katarzyna; Okrasa, Sebastian

2018-04-01

This paper presents the results of investigations of carbon films deposited by a modified version of the magnetron sputtering method - HiPGIMS (High Power Gas Injection Magnetron Sputtering). In this experiment, the magnetron system with inversely polarized electrodes (sputtered cathode at ground potential and positively biased, spatially separated anode) was used. This arrangement allowed us to conduct the experiment using voltages ranging from 1 to 2 kV and a power supply system equipped with 25/50 μF capacitor battery. Carbon films were investigated by VIS/UV Raman spectroscopy. Sp3/sp2 bonding ratio was evaluated basing the elementary components of registered spectra. Our investigation showed that sp3 bond content increases with discharge power but up to specific value only. In extreme conditions of generating plasma impulses, we detected a reversed relation of the sp3/sp2 ratio. In our opinion, a energy of plasma pulse favors nucleation of a sp3 phase because of a relatively higher ionization state but in extreme cases the influence of energy is reversed.

Characterization of sp3 bond content of carbon films deposited by high power gas injection magnetron sputtering method by UV and VIS Raman spectroscopy.

Science.gov (United States)

Zdunek, Krzysztof; Chodun, Rafał; Wicher, Bartosz; Nowakowska-Langier, Katarzyna; Okrasa, Sebastian

2018-04-05

This paper presents the results of investigations of carbon films deposited by a modified version of the magnetron sputtering method - HiPGIMS (High Power Gas Injection Magnetron Sputtering). In this experiment, the magnetron system with inversely polarized electrodes (sputtered cathode at ground potential and positively biased, spatially separated anode) was used. This arrangement allowed us to conduct the experiment using voltages ranging from 1 to 2kV and a power supply system equipped with 25/50μF capacitor battery. Carbon films were investigated by VIS/UV Raman spectroscopy. Sp 3 /sp 2 bonding ratio was evaluated basing the elementary components of registered spectra. Our investigation showed that sp 3 bond content increases with discharge power but up to specific value only. In extreme conditions of generating plasma impulses, we detected a reversed relation of the sp 3 /sp 2 ratio. In our opinion, a energy of plasma pulse favors nucleation of a sp 3 phase because of a relatively higher ionization state but in extreme cases the influence of energy is reversed. Copyright © 2018 Elsevier B.V. All rights reserved.

A novel power source for high-precision, highly efficient micro w-EDM

International Nuclear Information System (INIS)

Chen, Shun-Tong; Chen, Chi-Hung

2015-01-01

The study presents the development of a novel power source for high-precision, highly efficient machining of micropart microstructures using micro wire electrical discharge machining (w-EDM). A novel power source based on a pluri resistance–capacitance (pRC) circuit that can generate a high-frequency, high-peak current with a short pulse train is proposed and designed to enhance the performance of micro w-EDM processes. Switching between transistors is precisely controlled in the designed power source to create a high-frequency short-pulse train current. Various microslot cutting tests in both aluminum and copper alloys are conducted. Experimental results demonstrate that the pRC power source creates instant spark erosion resulting in markedly less material for removal, diminishing discharge crater size, and consequently an improved surface finish. A new evaluation approach for spark erosion ability (SEA) to assess the merits of micro EDM power sources is also proposed. In addition to increasing the speed of micro w-EDM by increasing wire feed rates by 1.6 times the original feed rate, the power source is more appropriate for machining micropart microstructures since there is less thermal breaking. Satisfactory cutting of an elaborate miniature hook-shaped structure and a high-aspect ratio microstructure with a squared-pillar array also reveal that the developed pRC power source is effective, and should be very useful in the manufacture of intricate microparts. (paper)

Temperature Stabilized Characterization of High Voltage Power Supplies

CERN Document Server

Krarup, Ole

2017-01-01

High precision measurements of the masses of nuclear ions in the ISOLTRAP experiment relies on an MR-ToF. A major source of noise and drift is the instability of the high voltage power supplies employed. Electrical noise and temperature changes can broaden peaks in time-of-flight spectra and shift the position of peaks between runs. In this report we investigate how the noise and drift of high-voltage power supplies can be characterized. Results indicate that analog power supplies generally have better relative stability than digitally controlled ones, and that the high temperature coefficients of all power supplies merit efforts to stabilize them.

High power diode lasers converted to the visible

DEFF Research Database (Denmark)

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

2017-01-01

High power diode lasers have in recent years become available in many wavelength regions. However, some spectral regions are not well covered. In particular, the visible spectral range is lacking high power diode lasers with good spatial quality. In this paper, we highlight some of our recent...... results in nonlinear frequency conversion of high power near infrared diode lasers to the visible spectral region....

Measurement of high-power microwave pulse under intense ...

Indian Academy of Sciences (India)

Abstract. KALI-1000 pulse power system has been used to generate single pulse nanosecond duration high-power microwaves (HPM) from a virtual cathode oscillator. (VIRCATOR) device. HPM power measurements were carried out using a transmitting– receiving system in the presence of intense high frequency (a few ...

Workshop on high power ICH antenna designs for high density tokamaks

International Nuclear Information System (INIS)

Aamodt, R.E.

1990-01-01

A workshop in high power ICH antenna designs for high density tokamaks was held in Boulder, Colorado on January 31 through February 2, 1990. The purposes of the workshop were to: (1) review the data base relevant to the high power heating of high density tokamaks; (2) identify the important issues which need to be addressed in order to ensure the success of the ICRF programs on CIT and Alcator C-MOD; and (3) recommend approaches for resolving the issues in a timely realistic manner. Some specific performance goals for the antenna system define a successful design effort. Simply stated these goals are: couple the specified power per antenna into the desired ion species; produce no more than an acceptable level of rf auxiliary power induced impurities; and have a mechanical structure which safely survives the thermal, mechanical and radiation stresses in the relevant environment. These goals are intimately coupled and difficult tradeoffs between scientific and engineering constraints have to be made

Neurodevelopmental problems and extremes in BMI

Directory of Open Access Journals (Sweden)

Nóra Kerekes

2015-07-01

Full Text Available Background. Over the last few decades, an increasing number of studies have suggested a connection between neurodevelopmental problems (NDPs and body mass index (BMI. Attention deficit/hyperactivity disorder (ADHD and autism spectrum disorders (ASD both seem to carry an increased risk for developing extreme BMI. However, the results are inconsistent, and there have been only a few studies of the general population of children.Aims. We had three aims with the present study: (1 to define the prevalence of extreme (low or high BMI in the group of children with ADHD and/or ASDs compared to the group of children without these NDPs; (2 to analyze whether extreme BMI is associated with the subdomains within the diagnostic categories of ADHD or ASD; and (3 to investigate the contribution of genetic and environmental factors to BMI in boys and girls at ages 9 and 12.Method. Parents of 9- or 12-year-old twins (n = 12,496 were interviewed using the Autism—Tics, ADHD and other Comorbidities (A-TAC inventory as part of the Child and Adolescent Twin Study in Sweden (CATSS. Univariate and multivariate generalized estimated equation models were used to analyze associations between extremes in BMI and NDPs.Results. ADHD screen-positive cases followed BMI distributions similar to those of children without ADHD or ASD. Significant association was found between ADHD and BMI only among 12-year-old girls, where the inattention subdomain of ADHD was significantly associated with the high extreme BMI. ASD scores were associated with both the low and the high extremes of BMI. Compared to children without ADHD or ASD, the prevalence of ASD screen-positive cases was three times greater in the high extreme BMI group and double as much in the low extreme BMI group. Stereotyped and repetitive behaviors were significantly associated with high extreme BMIs.Conclusion. Children with ASD, with or without coexisting ADHD, are more prone to have low or high extreme BMIs than

High-power sputtering employed for film deposition

International Nuclear Information System (INIS)

Shapovalov, V I

2017-01-01

The features of high-power magnetron sputtering employed for the films’ deposition are reviewed. The main physical phenomena accompanying high-power sputtering including ion-electron emission, gas rarefaction, ionization of sputtered atoms, self-sputtering, ion sound waves and the impact of the target heating are described. (paper)

Assessment of extreme hydrological conditions in the Bothnian Bay, Baltic Sea, and the impact of the nuclear power plant "Hanhikivi-1" on the local thermal regime

Science.gov (United States)

Dvornikov, Anton Y.; Martyanov, Stanislav D.; Ryabchenko, Vladimir A.; Eremina, Tatjana R.; Isaev, Alexey V.; Sein, Dmitry V.

2017-04-01

The results of the study aimed to assess the influence of future nuclear power plant Hanhikivi-1 upon the local thermal conditions in the Bothnian Bay in the Baltic Sea are presented. A number of experiments with different numerical models were also carried out in order to estimate the extreme hydro-meteorological conditions in the area of the construction. The numerical experiments were fulfilled both with analytically specified external forcing and with real external forcing for 2 years: a cold year (2010) and a warm year (2014). The study has shown that the extreme values of sea level and water temperature and the characteristics of wind waves and sea ice in the vicinity of the future nuclear power plant can be significant and sometimes catastrophic. Permanent release of heat into the marine environment from an operating nuclear power plant will lead to a strong increase in temperature and the disappearance of ice cover within a 2 km vicinity of the station. These effects should be taken into account when assessing local climate changes in the future.

Determination of optimal whole body vibration amplitude and frequency parameters with plyometric exercise and its influence on closed-chain lower extremity acute power output and EMG activity in resistance trained males

Science.gov (United States)

Hughes, Nikki J.

The optimal combination of Whole body vibration (WBV) amplitude and frequency has not been established. Purpose. To determine optimal combination of WBV amplitude and frequency that will enhance acute mean and peak power (MP and PP) output EMG activity in the lower extremity muscles. Methods. Resistance trained males (n = 13) completed the following testing sessions: On day 1, power spectrum testing of bilateral leg press (BLP) movement was performed on the OMNI. Days 2 and 3 consisted of WBV testing with either average (5.8 mm) or high (9.8 mm) amplitude combined with either 0 (sham control), 10, 20, 30, 40 and 50 Hz frequency. Bipolar surface electrodes were placed on the rectus femoris (RF), vastus lateralis (VL), bicep femoris (BF) and gastrocnemius (GA) muscles for EMG analysis. MP and PP output and EMG activity of the lower extremity were assessed pre-, post-WBV treatments and after sham-controls on the OMNI while participants performed one set of five repetitions of BLP at the optimal resistance determined on Day 1. Results. No significant differences were found between pre- and sham-control on MP and PP output and on EMG activity in RF, VL, BF and GA. Completely randomized one-way ANOVA with repeated measures demonstrated no significant interaction of WBV amplitude and frequency on MP and PP output and peak and mean EMGrms amplitude and EMG rms area under the curve. RF and VL EMGrms area under the curve significantly decreased (p plyometric exercise does not induce alterations in subsequent MP and PP output and EMGrms activity of the lower extremity. Future studies need to address the time of WBV exposure and magnitude of external loads that will maximize strength and/or power output.

E-beam high voltage switching power supply

Science.gov (United States)

Shimer, Daniel W.; Lange, Arnold C.

1997-01-01

A high power, solid state power supply is described for producing a controllable, constant high voltage output under varying and arcing loads suitable for powering an electron beam gun or other ion source. The present power supply is most useful for outputs in a range of about 100-400 kW or more. The power supply is comprised of a plurality of discrete switching type dc-dc converter modules, each comprising a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, and an output rectifier for producing a dc voltage at the output of each module. The inputs to the converter modules are fed from a common dc rectifier/filter and are linked together in parallel through decoupling networks to suppress high frequency input interactions. The outputs of the converter modules are linked together in series and connected to the input of the transmission line to the load through a decoupling and line matching network. The dc-dc converter modules are phase activated such that for n modules, each module is activated equally 360.degree./n out of phase with respect to a successive module. The phased activation of the converter modules, combined with the square current waveforms out of the step up transformers, allows the power supply to operate with greatly reduced output capacitance values which minimizes the stored energy available for discharge into an electron beam gun or the like during arcing. The present power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle using simulated voltage feedback signals and voltage feedback loops. Circuitry is also provided for sensing incipient arc currents reflected at the output of the power supply and for simultaneously decoupling the power supply circuitry from the arcing load.

E-beam high voltage switching power supply

International Nuclear Information System (INIS)

Shimer, D.W.; Lange, A.C.

1997-01-01

A high power, solid state power supply is described for producing a controllable, constant high voltage output under varying and arcing loads suitable for powering an electron beam gun or other ion source. The present power supply is most useful for outputs in a range of about 100-400 kW or more. The power supply is comprised of a plurality of discrete switching type dc-dc converter modules, each comprising a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, and an output rectifier for producing a dc voltage at the output of each module. The inputs to the converter modules are fed from a common dc rectifier/filter and are linked together in parallel through decoupling networks to suppress high frequency input interactions. The outputs of the converter modules are linked together in series and connected to the input of the transmission line to the load through a decoupling and line matching network. The dc-dc converter modules are phase activated such that for n modules, each module is activated equally 360 degree/n out of phase with respect to a successive module. The phased activation of the converter modules, combined with the square current waveforms out of the step up transformers, allows the power supply to operate with greatly reduced output capacitance values which minimizes the stored energy available for discharge into an electron beam gun or the like during arcing. The present power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle using simulated voltage feedback signals and voltage feedback loops. Circuitry is also provided for sensing incipient arc currents reflected at the output of the power supply and for simultaneously decoupling the power supply circuitry from the arcing load. 7 figs

Large-solid-angle illuminators for extreme ultraviolet lithography with laser plasmas

International Nuclear Information System (INIS)

Kubiak, G.D.; Tichenor, D.A.; Sweatt, W.C.; Chow, W.W.

1995-06-01

Laser Plasma Sources (LPSS) of extreme ultraviolet radiation are an attractive alternative to synchrotron radiation sources for extreme ultraviolet lithography (EUVL) due to their modularity, brightness, and modest size and cost. To fully exploit the extreme ultraviolet power emitted by such sources, it is necessary to capture the largest possible fraction of the source emission half-sphere while simultaneously optimizing the illumination stationarity and uniformity on the object mask. In this LDRD project, laser plasma source illumination systems for EUVL have been designed and then theoretically and experimentally characterized. Ellipsoidal condensers have been found to be simple yet extremely efficient condensers for small-field EUVL imaging systems. The effects of aberrations in such condensers on extreme ultraviolet (EUV) imaging have been studied with physical optics modeling. Lastly, the design of an efficient large-solid-angle condenser has been completed. It collects 50% of the available laser plasma source power at 14 nm and delivers it properly to the object mask in a wide-arc-field camera

High Power laser power conditioning system new discharge circuit research

CERN Document Server

Li Yi; Peng Han Sheng; Zhou Pei Zhang; Zheng Wan Guo; Guo Lang Fu; Chen Li Hua; Chen De Hui; Lai Gui You; Luan Yong Ping

2002-01-01

The new discharge circuit of power conditioning system for high power laser is studied. The theoretical model of the main discharge circuit is established. The pre-ionization circuit is studied in experiment. In addition, the explosion energy of the new large xenon lamp is successfully measured. The conclusion has been applied to 4 x 2 amplifier system

Recent and future warm extreme events and high-mountain slope stability.

Science.gov (United States)

Huggel, C; Salzmann, N; Allen, S; Caplan-Auerbach, J; Fischer, L; Haeberli, W; Larsen, C; Schneider, D; Wessels, R

2010-05-28

The number of large slope failures in some high-mountain regions such as the European Alps has increased during the past two to three decades. There is concern that recent climate change is driving this increase in slope failures, thus possibly further exacerbating the hazard in the future. Although the effects of a gradual temperature rise on glaciers and permafrost have been extensively studied, the impacts of short-term, unusually warm temperature increases on slope stability in high mountains remain largely unexplored. We describe several large slope failures in rock and ice in recent years in Alaska, New Zealand and the European Alps, and analyse weather patterns in the days and weeks before the failures. Although we did not find one general temperature pattern, all the failures were preceded by unusually warm periods; some happened immediately after temperatures suddenly dropped to freezing. We assessed the frequency of warm extremes in the future by analysing eight regional climate models from the recently completed European Union programme ENSEMBLES for the central Swiss Alps. The models show an increase in the higher frequency of high-temperature events for the period 2001-2050 compared with a 1951-2000 reference period. Warm events lasting 5, 10 and 30 days are projected to increase by about 1.5-4 times by 2050 and in some models by up to 10 times. Warm extremes can trigger large landslides in temperature-sensitive high mountains by enhancing the production of water by melt of snow and ice, and by rapid thaw. Although these processes reduce slope strength, they must be considered within the local geological, glaciological and topographic context of a slope.

Chaos in high-power high-frequency gyrotrons

International Nuclear Information System (INIS)

Airila, M.

2004-01-01

Gyrotron interaction is a complex nonlinear dynamical process, which may turn chaotic in certain circumstances. The emergence of chaos renders dynamical systems unpredictable and causes bandwidth broadening of signals. Such effects would jeopardize the prospect of advanced gyrotrons in fusion. Therefore, it is important to be aware of the possibility of chaos in gyrotrons. There are three different chaos scenarios closely related to the development of high-power gyrotrons: First, the onset of chaos in electron trajectories would lead to difficulties in the design and efficient operation of depressed potential collectors, which are used for efficiency enhancement. Second, the radio-frequency signal could turn chaotic, decreasing the output power and the spectral purity of the output signal. As a result, mode conversion, transmission, and absorption efficiencies would be reduced. Third, spatio-temporal chaos in the resonator field structure can set a limit for the use of large-diameter interaction cavities and high-order TE modes (large azimuthal index) allowing higher generated power. In this thesis, the issues above are addressed with numerical modeling. It is found that chaos in electron residual energies is practically absent in the parameter region corresponding to high efficiency. Accordingly, depressed collectors are a feasible solution also in advanced high-power gyrotrons. A new method is presented for straightforward numerical solution of the one-dimensional self-consistent time-dependent gyrotron equations, and the method is generalized to two dimensions. In 1D, a chart of gyrotron oscillations is calculated. It is shown that the regions of stationary oscillations, automodulation, and chaos have a complicated topology in the plane of generalized gyrotron variables. The threshold current for chaotic oscillations exceeds typical operating currents by a factor of ten. However, reflection of the output signal may significantly lower the threshold. 2D

Development of an Extreme Environment Materials Research Facility at Princeton

International Nuclear Information System (INIS)

Cohen, A.B.; Gentile, C.A.; Tully, C.G.; Austin, R.; Calaprice, F.; McDonald, K.; Ascione, G.; Baker, G.; Davidson, R.; Dudek, L.; Grisham, L.; Kugel, H.; Pagdon, K.; Stevenson, T.; Woolley, R.; Zwicker, A.

2010-01-01

The need for a fundamental understanding of material response to a neutron and/or high heat flux environment can yield development of improved materials and operations with existing materials. Such understanding has numerous applications in fields such as nuclear power (for the current fleet and future fission and fusion reactors), aerospace, and other research fields (e.g., high-intensity proton accelerator facilities for high energy physics research). A proposal has been advanced to develop a facility for testing various materials under extreme heat and neutron exposure conditions at Princeton. The Extreme Environment Materials Research Facility comprises an environmentally controlled chamber (48 m 3 ) capable of high vacuum conditions, with extreme flux beams and probe beams accessing a central, large volume target. The facility will have the capability to expose large surface areas (1 m 2 ) to 14 MeV neutrons at a fluence in excess of 10 13 n/s. Depending on the operating mode. Additionally beam line power on the order of 15-75 MW/m 2 for durations of 1-15 seconds are planned. The multi-second duration of exposure can be repeated every 2-10 minutes for periods of 10-12 hours. The facility will be housed in the test cell that held the Tokamak Fusion Test Reactor (TFTR), which has the desired radiation and safety controls as well as the necessary loading and assembly infrastructure. The facility will allow testing of various materials to their physical limit of thermal endurance and allow for exploring the interplay between radiation-induced embrittlement, swelling and deformation of materials, and the fatigue and fracturing that occur in response to thermal shocks. The combination of high neutron energies and intense fluences will enable accelerated time scale studies. The results will make contributions for refining predictive failure modes (modeling) in extreme environments, as well as providing a technical platform for the development of new alloys, new

INLA goes extreme: Bayesian tail regression for the estimation of high spatio-temporal quantiles

KAUST Repository

Opitz, Thomas; Huser, Raphaë l; Bakka, Haakon; Rue, Haavard

2018-01-01

approach is based on a Bayesian generalized additive modeling framework that is designed to estimate complex trends in marginal extremes over space and time. First, we estimate a high non-stationary threshold using a gamma distribution for precipitation

The effect of low extremity plyometric training on back muscle power of high school throwing event athletes.

Science.gov (United States)

Park, Gi Duck; Lee, Joong Chul; Lee, Juri

2014-01-01

[Purpose] The physical strength elements required for athletic throwing events include muscle strength, swiftness, agility, speed, flexibility, and physical balance. Although plyometric training and weight training are implemented as representative training methods for improving swiftness and agility, most studies of it have been conducted with players of other sports. [Subjects] The study subjects were 10 throwing event athletes attending K physical education high school. The subjects were randomly assigned to a control group of five subjects and an experimental group of five subjects. To analyze the body composition, an Inbody 3.0 instrument (Biospace, Korea) was used as experimental equipment to measure heights, weight, body fat percentages, and muscle masses and a Biodex system 4.0 (BIODEX, USA) was used to measure isokinetic muscle-joint and lumbar muscle strengths. The plyometric training consisted of 15 techniques out of the training methods introduced in the 'Power up plyometric training'. The plyometric program was implemented without any training load three times per week during daybreak exercises for the experimental group. The number of times and the number of sets were changed over time as follows: three sets of 10 times in the 1st -4th weeks, three sets of 15 times in the 5th-8th weeks, and five sets of 15 times in the 9th-12th weeks. [Results] According to the ANCOVA results of lumbar extensor muscle strength at 60°/sec, the overall reliability of the model was significant. According to the ANCOVA results of lumbar flexor muscle strength at 60°/sec, the overall reliability of the model was significant. [Conclusion] Plyometric training positively affected high school throwing event athletes. To summarize the study findings, the application of plyometric training with high intensity and loads improved the results of athletes who perform highly intensive exercises at normal times.

Atmospheric Propagation and Combining of High-Power Lasers

Science.gov (United States)

2015-09-08

Brightness-scaling potential of actively phase- locked solid state laser arrays,” IEEE J. Sel. Topics Quantum Electron., vol. 13, no. 3, pp. 460–472, May...attempting to phase- lock high-power lasers, which is not encountered when phase- locking low-power lasers, for example mW power levels. Regardless, we...technology does not currently exist. This presents a challenging problem when attempting to phase- lock high-power lasers, which is not encountered when

Hydrogen fuel cell power system

International Nuclear Information System (INIS)

Lam, A.W.

2004-01-01

'Full text:' Batteries are typically a necessary and prime component of any DC power system, providing a source of on-demand stored energy with proven reliability. The integration of batteries and basic fuel cells for mobile and stationary utility applications poses a new challenge. For high value applications, the specification and operating requirements for this hybrid module differ from conventional requirements as the module must withstand extreme weather conditions and provide extreme reliability. As an electric utility company, BCHydro has embarked in the development and application of a Hydrogen Fuel Cell Power Supply (HFCPS) for field trial. A Proton Exchange Membrane (PEM)- type fuel cell including power electronic modules are mounted in a standard 19-inch rack that provides 48V, 24V, 12V DC and 120V AC outputs. The hydrogen supply consists of hydrogen bottles and regulating devices to provide a continuous fuel source to the power modules. Many tests and evaluations have been done to ensure the HFCPS package is robust and suitable for electric utility grade operation. A field trial demonstrating this standalone system addressed reliability, durability, and installation concerns as well as developed the overall system operating procedures. (author)

Transient analysis of the output short-circuit fault of high power and high voltage DC power supply

International Nuclear Information System (INIS)

Yang Zhigang; Zhang Jian; Huang Yiyun; Hao Xu; Sun Haozhang; Guo Fei

2014-01-01

The transient conditions of output short-circuit fault of high voltage DC power supply was introduced, and the energy of power supply injecting into klystron during the protection process of three-electrode gas switch were analyzed and calculated in detail when klystron load happening electrode arc faults. The results of calculation and simulation are consistent with the results of the experiment. When the output short-circuit fault of high voltage power supply occurs, switch can be shut off in the microsecond, and the short circuit current can be controlled in 200 A. It has verified the rapidity and reliability of the three-electrode gas switch protection, and it has engineering application value. (authors)

Steep Hard-X-ray Spectra Indicate Extremely High Accretion Rates in Weak Emission-Line Quasars

Science.gov (United States)

Marlar, Andrea; Shemmer, Ohad; Anderson, Scott F.; Brandt, W. Niel; Diamond-Stanic, Aleksandar M.; Fan, Xiaohui; Luo, Bin; Plotkin, Richard; Richards, Gordon T.; Schneider, Donald P.; Wu, Jianfeng

2018-06-01

We present XMM-Newton imaging spectroscopy of ten weak emission-line quasars (WLQs) at 0.928 ≤ z ≤ 3.767, six of which are radio quiet and four which are radio intermediate. The new X-ray data enabled us to measure the hard-X-ray power-law photon index (Γ) in each source with relatively high accuracy. These measurements allowed us to confirm previous reports that WLQs have steeper X-ray spectra, therefore indicating higher accretion rates with respect to "typical" quasars. A comparison between the Γ values of our radio-quiet WLQs and those of a carefully-selected, uniform sample of 84 quasars shows that the first are significantly higher, at the ≥ 3σ level. Collectively, the four radio-intermediate WLQs have lower Γ values with respect to the six radio-quiet WLQs, as may be expected if the spectra of the first group are contaminated by X-ray emission from a jet. These results suggest that, in the absence of significant jet emission along our line of sight, WLQs constitute the extreme high end of the accretion rate distribution in quasars. We detect soft excess emission in our lowest-redshift radio-quiet WLQ, in agreement with previous findings suggesting that the prominence of this feature is associated with a high accretion rate. We have not detected signatures of Compton reflection, Fe Kα lines, or strong variability between two X-ray epochs in any of our WLQs.

Modular Ultra-High Power Solar Array Architecture, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Deployable Space Systems, Inc. (DSS) will focus the proposed SBIR program on the development of a new highly-modularized and extremely-scalable solar array that...

Design and development of power supplies for high power IOT based RF amplifier

International Nuclear Information System (INIS)

Kumar, Yashwant; Kumari, S.; Ghosh, M.K.; Bera, A.; Sadhukhan, A.; Pal, S.S.; Khare, V.K.; Tiwari, T.P.; Thakur, S.K.; Saha, S.

2013-01-01

Design, development, circuit topology, function of system components and key system specifications of different power supplies for biasing electrodes of Thales Inductive Output Tube (IOT) based high power RF amplifier are presented in this paper. A high voltage power supply (-30 kV, 3.2A dc) with fast (∼microsecond) crowbar protection circuit is designed, developed and commissioned at VECC for testing the complete setup. Other power supplies for biasing grid electrode (300V, 0.5A dc) and Ion Pump (3 kV, 0.1mA dc) of IOT are also designed, developed and tested with actual load. A HV Deck (60kV Isolation) is specially designed in house to place these power supplies which are floating at 30 kV. All these power supplies are powered by an Isolation Transformer (5 kVA, 60 kV isolation) designed and developed in VECC. (author)

Exploring new frontiers in the pulsed power laboratory: Recent progress

Directory of Open Access Journals (Sweden)

S. Adamenko

2015-01-01

Full Text Available One of the most fundamental processes in the Universe, nucleosynthesis of elements drives energy production in stars as well as the creation of all atoms heavier than hydrogen. To harness this process and open new ways for energy production, we must recreate some of the extreme conditions in which it occurs. We present results of experiments using a pulsed power facility to induce collective nuclear interactions producing stable nuclei of virtually every element in the periodic table. A high-power electron beam pulse striking a small metallic target is used to create the extreme dynamic environment. Material analysis studies detect an anomalously high presence of new chemical elements in the remnants of the exploded target supporting theoretical conjectures of the experiment. These results provide strong motivation to continue our research looking for additional proofs that heavy element nucleosynthesis is possible in pulsed power laboratory.

Driver Circuit For High-Power MOSFET's

Science.gov (United States)

Letzer, Kevin A.

1991-01-01

Driver circuit generates rapid-voltage-transition pulses needed to switch high-power metal oxide/semiconductor field-effect transistor (MOSFET) modules rapidly between full "on" and full "off". Rapid switching reduces time of overlap between appreciable current through and appreciable voltage across such modules, thereby increasing power efficiency.

Hazard analysis of typhoon-related external events using extreme value theory

Energy Technology Data Exchange (ETDEWEB)

Kim, Yo Chan; Jang, Seung Cheol [Integrated Safety Assessment Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lim, Tae Jin [Dept. of Industrial Information Systems Engineering, Soongsil University, Seoul (Korea, Republic of)

2015-02-15

After the Fukushima accident, the importance of hazard analysis for extreme external events was raised. To analyze typhoon-induced hazards, which are one of the significant disasters of East Asian countries, a statistical analysis using the extreme value theory, which is a method for estimating the annual exceedance frequency of a rare event, was conducted for an estimation of the occurrence intervals or hazard levels. For the four meteorological variables, maximum wind speed, instantaneous wind speed, hourly precipitation, and daily precipitation, the parameters of the predictive extreme value theory models were estimated. The 100-year return levels for each variable were predicted using the developed models and compared with previously reported values. It was also found that there exist significant long-term climate changes of wind speed and precipitation. A fragility analysis should be conducted to ensure the safety levels of a nuclear power plant for high levels of wind speed and precipitation, which exceed the results of a previous analysis.

An Overview of Science Challenges Pertaining to our Understanding of Extreme Geomagnetically Induced Currents. Chapter 8

Science.gov (United States)

Ngwira, Chigomezyo M.; Pulkkinen, Antti A.

2018-01-01

Vulnerability of man-made infrastructure to Earth-directed space weather events is a serious concern for today's technology-dependent society. Space weather-driven geomagnetically induced currents (GICs) can disrupt operation of extended electrically conducting technological systems. The threat of adverse impacts on critical technological infrastructure, like power grids, oil and gas pipelines, and communication networks, has sparked renewed interest in extreme space weather. Because extreme space weather events have low occurrence rate but potentially high impact, this presents a major challenge for our understanding of extreme GIC activity. In this chapter, we discuss some of the key science challenges pertaining to our understanding of extreme events. In addition, we present an overview of GICs including highlights of severe impacts over the last 80 years and recent U.S. Federal actions relevant to this community.

High power industrial picosecond laser from IR to UV

Science.gov (United States)

Saby, Julien; Sangla, Damien; Pierrot, Simonette; Deslandes, Pierre; Salin, François

2013-02-01

Many industrial applications such as glass cutting, ceramic micro-machining or photovoltaic processes require high average and high peak power Picosecond pulses. The main limitation for the expansion of the picosecond market is the cost of high power picosecond laser sources, which is due to the complexity of the architecture used for picosecond pulse amplification, and the difficulty to keep an excellent beam quality at high average power. Amplification with fibers is a good technology to achieve high power in picosecond regime but, because of its tight confinement over long distances, light undergoes dramatic non linearities while propagating in fibers. One way to avoid strong non linearities is to increase fiber's mode area. Nineteen missing holes fibers offering core diameter larger than 80μm have been used over the past few years [1-3] but it has been shown that mode instabilities occur at approximately 100W average output power in these fibers [4]. Recently a new fiber design has been introduced, in which HOMs are delocalized from the core to the clad, preventing from HOMs amplification [5]. In these so-called Large Pitch Fibers, threshold for mode instabilities is increased to 294W offering robust single-mode operation below this power level [6]. We have demonstrated a high power-high efficiency industrial picosecond source using single-mode Large Pitch rod-type fibers doped with Ytterbium. Large Pitch Rod type fibers can offer a unique combination of single-mode output with a very large mode area from 40 μm up to 100μm and very high gain. This enables to directly amplify a low power-low energy Mode Locked Fiber laser with a simple amplification architecture, achieving very high power together with singlemode output independent of power level or repetition rate.

High power neutral beam injection in LHD

International Nuclear Information System (INIS)

Tsumori, K.; Takeiri, Y.; Nagaoka, K.

2005-01-01

The results of high power injection with a neutral beam injection (NBI) system for the large helical device (LHD) are reported. The system consists of three beam-lines, and two hydrogen negative ion (H - ion) sources are installed in each beam-line. In order to improve the injection power, the new beam accelerator with multi-slot grounded grid (MSGG) has been developed and applied to one of the beam-lines. Using the accelerator, the maximum powers of 5.7 MW were achieved in 2003 and 2004, and the energy of 189 keV reached at maximum. The power and energy exceeded the design values of the individual beam-line for LHD. The other beam-lines also increased their injection power up to about 4 MW, and the total injection power of 13.1 MW was achieved with three beam-lines in 2003. Although the accelerator had an advantage in high power beam injection, it involved a demerit in the beam focal condition. The disadvantage was resolved by modifying the aperture shapes of the steering grid. (author)

High-power microwave diplexers for advanced ECRH systems

International Nuclear Information System (INIS)

Kasparek, W.; Petelin, M.; Erckmann, V.; Bruschi, A.; Noke, F.; Purps, F.; Hollmann, F.; Koshurinov, Y.; Lubyako, L.; Plaum, B.; Wubie, W.

2009-01-01

In electron cyclotron resonance heating systems, high-power multiplexers can be employed as power combiners, adjustable power dividers, fast switches to toggle the power between two launchers, as well as frequency sensitive directional couplers to combine heating and diagnostic applications on one launcher. In the paper, various diplexer designs for quasi-optical and corrugated waveguide transmission systems are discussed. Numerical calculations, low-power tests and especially high-power experiments performed at the ECRH system of W7-X are shown, which demonstrate the capability of these devices. Near term plans for applications on ASDEX Upgrade and FTU are presented. Based on the present results, options for implementation of power combiners and fast switches in the ECRH system of ITER is discussed.

Optimization with Extremal Dynamics

International Nuclear Information System (INIS)

Boettcher, Stefan; Percus, Allon G.

2001-01-01

We explore a new general-purpose heuristic for finding high-quality solutions to hard discrete optimization problems. The method, called extremal optimization, is inspired by self-organized criticality, a concept introduced to describe emergent complexity in physical systems. Extremal optimization successively updates extremely undesirable variables of a single suboptimal solution, assigning them new, random values. Large fluctuations ensue, efficiently exploring many local optima. We use extremal optimization to elucidate the phase transition in the 3-coloring problem, and we provide independent confirmation of previously reported extrapolations for the ground-state energy of ±J spin glasses in d=3 and 4

High-power fiber-coupled pump lasers for fiber lasers

Science.gov (United States)

Kasai, Yohei; Aizawa, Takuya; Tanaka, Daiichiro

2018-02-01

We present high-power fiber-coupled pump modules utilized effectively for ultra-high power single-mode (SM) fiber lasers. Maximum output power of 392 W was achieved at 23 A for 915 nm pump, and 394 W for 976 nm pump. Fiber core diameter is 118 μm and case temperature is 25deg. C. Polarization multiplexing technique was newly applied to our optical system. High-reliability of the laser diodes (LD) at high-power operation has been demonstrated by aging tests. Advanced package structure was developed that manages uncoupled light around input end of the fiber. 800 hours continuous drive with uncoupled light power of 100 W has been achieved.

A high pulsed power supply system designed for pulsed high magnetic field

International Nuclear Information System (INIS)

Liu Kefu; Wang Shaorong; Zhong Heqing; Xu Yan; Pan Yuan

2008-01-01

This paper introduces the design of high pulsed power supply system for producing pulsed high magnetic field up to 70 T. This system consists of 58 sets of 55 μF of capacitor bank which provides 1.0 MJ energy storage. A set of vacuum closing switch is chosen as main switch for energy discharge into magnetic coil. A crowbar circuit with high power diodes in series with resistor is used to absorb the redundant energy and adjust pulse width. The resistance of magnetic coil changing with current is deduced by energy balance equations. A capacitor-charging power supply using a series-resonant, constant on-time variable frequency control, and zero-current switching charges the capacitor bank in one minute time with high efficiency. The pulsed power supply provides adjustable current and pulse width with 30 kA peak and 30 ms maximum. The primary experiments demonstrate the system reliability. This work provides an engineering guidance for future development of pulsed high magnetic field. (authors)

High-power laser diodes with high polarization purity

Science.gov (United States)

Rosenkrantz, Etai; Yanson, Dan; Peleg, Ophir; Blonder, Moshe; Rappaport, Noam; Klumel, Genady

2017-02-01

Fiber-coupled laser diode modules employ power scaling of single emitters for fiber laser pumping. To this end, techniques such as geometrical, spectral and polarization beam combining (PBC) are used. For PBC, linear polarization with high degree of purity is important, as any non-perfectly polarized light leads to losses and heating. Furthermore, PBC is typically performed in a collimated portion of the beams, which also cancels the angular dependence of the PBC element, e.g., beam-splitter. However, we discovered that single emitters have variable degrees of polarization, which depends both on the operating current and far-field divergence. We present data to show angle-resolved polarization measurements that correlate with the ignition of high-order modes in the slow-axis emission of the emitter. We demonstrate that the ultimate laser brightness includes not only the standard parameters such as power, emitting area and beam divergence, but also the degree of polarization (DoP), which is a strong function of the latter. Improved slow-axis divergence, therefore, contributes not only to high brightness but also high beam combining efficiency through polarization.

Market Prices in a Power Market with more than 50% Wind Power

DEFF Research Database (Denmark)

Skytte, Klaus; Grohnheit, Poul Erik

2018-01-01

Denmark has the highest proportion of wind power in the world. Wind power provided a world record of 39.1% of the total annual Danish electricity consumption in 2014 with as much as 51.7% in Western Denmark. Many would argue that the present power markets are not designed for such high shares...... of wind power production and that it would be hard to get good and stable prices. However, analyses in this chapter show that the Nordic power market works, extreme events have been few, and the current infrastructure and market organization has been able to handle the amount of wind power installed so...... far. It is found that geographical bidding areas for the wholesale electricity market reflect external transmission constraints caused by wind power. The analyses in this chapter use hourly data from West Denmark—which has the highest share of wind energy in Denmark and which is a separate price area...

Market Prices in a Power Market with more than 50% Wind Power

DEFF Research Database (Denmark)

Skytte, Klaus; Grohnheit, Poul Erik

2017-01-01

Denmark has the highest proportion of wind power in the world. Wind power provided a world record of 39.1% of the total annual Danish electricity consumption in 2014 with as much as 51.7% in Western Denmark. Many would argue that the present power markets are not designed for such high shares...... of wind power production and that it would be hard to get good and stable prices. However, analyses in this chapter show that the Nordic power market works, extreme events have been few, and the current infrastructure and market organization has been able to handle the amount of wind power installed so...... far. It is found that geographical bidding areas for the wholesale electricity market reflect external transmission constraints caused by wind power. The analyses in this chapter use hourly data from West Denmark—which has the highest share of wind energy in Denmark and which is a separate price area...

The Effect of Sport Specialization on Lower Extremity Injury Rates in High School Athletes

OpenAIRE

McGuine, Timothy A.; Bell, David; Brooks, Margaret Alison; Hetzel, Scott; Pfaller, Adam; Post, Eric

2017-01-01

Objectives: Sport specialization has been shown to be associated with increased risk of musculoskeletal lower extremity injuries (LEI) in adolescent athletes presenting in clinical settings. However, the association of sport specialization and incidence of LEI has not been studied prospectively in a large population of adolescent athletes. The objective of this study was to compare the incidence of LEI in high school athletes identified as having low (LOW), moderate (MOD) or high (HIGH) level...

High-power VCSELs for smart munitions

Science.gov (United States)

Geske, Jon; MacDougal, Michael; Cole, Garrett; Snyder, Donald

2006-08-01

The next generation of low-cost smart munitions will be capable of autonomously detecting and identifying targets aided partly by the ability to image targets with compact and robust scanning rangefinder and LADAR capabilities. These imaging systems will utilize arrays of high performance, low-cost semiconductor diode lasers capable of achieving high peak powers in pulses ranging from 5 to 25 nanoseconds in duration. Aerius Photonics is developing high-power Vertical-Cavity Surface-Emitting Lasers (VCSELs) to meet the needs of these smart munitions applications. The authors will report the results of Aerius' development program in which peak pulsed powers exceeding 60 Watts were demonstrated from single VCSEL emitters. These compact packaged emitters achieved pulse energies in excess of 1.5 micro-joules with multi kilo-hertz pulse repetition frequencies. The progress of the ongoing effort toward extending this performance to arrays of VCSEL emitters and toward further improving laser slope efficiency will be reported.

Extreme ultraviolet narrow band emission from electron cyclotron resonance plasmas

International Nuclear Information System (INIS)

Zhao, H. Y.; Zhao, H. W.; Sun, L. T.; Zhang, X. Z.; Wang, H.; Ma, B. H.; Li, X. X.; Zhu, Y. H.; Sheng, L. S.; Zhang, G. B.; Tian, Y. C.

2008-01-01

Extreme ultraviolet lithography (EUVL) is considered as the most promising solution at and below dynamic random access memory 32 nm half pitch among the next generation lithography, and EUV light sources with high output power and sufficient lifetime are crucial for the realization of EUVL. However, there is no EUV light source completely meeting the requirements for the commercial application in lithography yet. Therefore, ECR plasma is proposed as a novel concept EUV light source. In order to investigate the feasibility of ECR plasma as a EUV light source, the narrow band EUV power around 13.5 nm emitted by two highly charged ECR ion sources--LECR2M and SECRAL--was measured with a calibrated EUV power measurement tool. Since the emission lines around 13.5 nm can be attributed to the 4d-5p transitions of Xe XI or the 4d-4f unresolved transition array of Sn VIII-XIII, xenon plasma was investigated. The dependence of the EUV throughput and the corresponding conversion efficiency on the parameters of the ion source, such as the rf power and the magnetic confinement configurations, were preliminarily studied

Flexible asymmetric supercapacitors with high energy and high power density in aqueous electrolytes

Science.gov (United States)

Cheng, Yingwen; Zhang, Hongbo; Lu, Songtao; Varanasi, Chakrapani V.; Liu, Jie

2013-01-01

Supercapacitors with both high energy and high power densities are critical for many practical applications. In this paper, we discuss the design and demonstrate the fabrication of flexible asymmetric supercapacitors based on nanocomposite electrodes of MnO2, activated carbon, carbon nanotubes and graphene. The combined unique properties of each of these components enable highly flexible and mechanically strong films that can serve as electrodes directly without using any current collectors or binders. Using these flexible electrodes and a roll-up approach, asymmetric supercapacitors with 2 V working voltage were successfully fabricated. The fabricated device showed excellent rate capability, with 78% of the original capacitance retained when the scan rate was increased from 2 mV s-1 to 500 mV s-1. Owing to the unique composite structure, these supercapacitors were able to deliver high energy density (24 W h kg-1) under high power density (7.8 kW kg-1) conditions. These features could enable supercapacitor based energy storage systems to be very attractive for a variety of critical applications, such as the power sources in hybrid electric vehicles and the back-up powers for wind and solar energy, where both high energy density and high power density are required.Supercapacitors with both high energy and high power densities are critical for many practical applications. In this paper, we discuss the design and demonstrate the fabrication of flexible asymmetric supercapacitors based on nanocomposite electrodes of MnO2, activated carbon, carbon nanotubes and graphene. The combined unique properties of each of these components enable highly flexible and mechanically strong films that can serve as electrodes directly without using any current collectors or binders. Using these flexible electrodes and a roll-up approach, asymmetric supercapacitors with 2 V working voltage were successfully fabricated. The fabricated device showed excellent rate capability, with 78% of

Design of 120 MW beam power electron gun for high power klystron

International Nuclear Information System (INIS)

Zhou Zusheng; Dong Dong

2005-01-01

An electron gun was designed and the beam optics for a China-made 50 MW klystron was simulated. The electron gun ceramic cylinder was designed and optimized. The China-made cathode was replaced with an imported one to lessen evaporation and arcing. The high voltage (320 kV) of the cathode was increased to meet the klystron output power demand and a low electric field strength (22.1 kV/mm) electron gun was designed to avoid the high power operation which damaged the ceramic cylinder. The klystron output power was increased and life span extended. (authors)

Los Alamos high-power proton linac designs

Energy Technology Data Exchange (ETDEWEB)

Lawrence, G.P. [Los Alamos National Laboratory, NM (United States)

1995-10-01

Medium-energy high-power proton linear accelerators have been studied at Los Alamos as drivers for spallation neutron applications requiring large amounts of beam power. Reference designs for such accelerators are discussed, important design factors are reviewed, and issues and concern specific to this unprecedented power regime are discussed.

High power laser exciter accelerators

International Nuclear Information System (INIS)

Martin, T.H.

1975-01-01

Recent developments in untriggered oil and water switching now permit the construction of compact, high energy density pulsed power sources for laser excitation. These accelerators, developed principally for electron beam fusion studies, appear adaptable to laser excitation and will provide electron beams of 10 13 to 10 14 W in the next several years. The accelerators proposed for e-beam fusion essentially concentrate the available power from the outside edge of a disk into the central region where the electron beam is formed. One of the main problem areas, that of power flow at the vacuum diode insulator, is greatly alleviated by the multiplicity of electron beams that are allowable for laser excitation. A proposal is made whereby the disk-shaped pulsed power sections are stacked vertically to form a series of radially flowing electron beams to excite the laser gas volume. (auth)

Design and development of high voltage high power operational ...

Indian Academy of Sciences (India)

address this challenge, a) Designing a discrete power opamp with high .... the use of high-impedance feedback networks, thus minimizing their output loading ... Spice simulation is done for the circuit and results are given in figures 4a–c.

SiC Power MOSFET with Improved Gate Dielectric

Energy Technology Data Exchange (ETDEWEB)

Sbrockey, Nick M. [Structured Materials Industries, Inc., Piscataway, NJ (United States); Tompa, Gary S. [Structured Materials Industries, Inc., Piscataway, NJ (United States); Spencer, Michael G. [Structured Materials Industries, Inc., Piscataway, NJ (United States); Chandrashekhar, Chandra M.V. S. [Structured Materials Industries, Inc., Piscataway, NJ (United States)

2010-08-23

In this STTR program, Structured Materials Industries (SMI), and Cornell University are developing novel gate oxide technology, as a critical enabler for silicon carbide (SiC) devices. SiC is a wide bandgap semiconductor material, with many unique properties. SiC devices are ideally suited for high-power, highvoltage, high-frequency, high-temperature and radiation resistant applications. The DOE has expressed interest in developing SiC devices for use in extreme environments, in high energy physics applications and in power generation. The development of transistors based on the Metal Oxide Semiconductor Field Effect Transistor (MOSFET) structure will be critical to these applications.

Assessing Climate Variability using Extreme Rainfall and ...

African Journals Online (AJOL)

user1

extreme frequency); the average intensity of rainfall from extreme events ... frequency and extreme intensity indices, suggesting that extreme events are more frequent and intense during years with high rainfall. The proportion of total rainfall from ...

The NASA CSTI High Capacity Power Program

International Nuclear Information System (INIS)

Winter, J.M.

1991-09-01

The SP-100 program was established in 1983 by DOD, DOE, and NASA as a joint program to develop the technology necessary for space nuclear power systems for military and civil applications. During 1986 and 1987, the NASA Advanced Technology Program was responsible for maintaining the momentum of promising technology advancement efforts started during Phase 1 of SP-100 and to strengthen, in key areas, the chances for successful development and growth capability of space nuclear reactor power systems for future space applications. In 1988, the NASA Advanced Technology Program was incorporated into NASA's new Civil Space Technology Initiative (CSTI). The CSTI program was established to provide the foundation for technology development in automation and robotics, information, propulsion, and power. The CSTI High Capacity Power Program builds on the technology efforts of the SP-100 program, incorporates the previous NASA advanced technology project, and provides a bridge to the NASA exploration technology programs. The elements of CSTI high capacity power development include conversion systems: Stirling and thermoelectric, thermal management, power management, system diagnostics, and environmental interactions. Technology advancement in all areas, including materials, is required to provide the growth capability, high reliability, and 7 to 10 year lifetime demanded for future space nuclear power systems. The overall program will develop and demonstrate the technology base required to provide a wide range of modular power systems while minimizing the impact of day/night operations as well as attitudes and distance from the Sun. Significant accomplishments in all of the program elements will be discussed, along with revised goals and project timelines recently developed

High-power semiconductor RSD-based switch

Energy Technology Data Exchange (ETDEWEB)

Bezuglov, V G; Galakhov, I V; Grusin, I A [All-Russian Scientific Research Inst. of Experimental Physics, Sarov (Russian Federation); and others

1997-12-31

The operating principle and test results of a high-power semiconductor RSD-based switch with the following operating parameters is described: operating voltage 25 kV, peak operating current 200 kA, maximum transferred charge 70 C. The switch is intended for use by high-power capacitor banks of state-of-the-art research facilities. The switch was evaluated for applicability in commercial pulsed systems. The possibility of increasing the peak operating current to 500 kA is demonstrated. (author). 4 figs., 2 refs.

Experiments on high power EB evaporation of niobium

International Nuclear Information System (INIS)

Kandaswamy, E.; Bhardwaj, R.L.; Ram Gopal; Ray, A.K.; Kulgod, S.V.

2002-01-01

Full text: The versatility of electron beam evaporation makes the deposition of many new and unusual materials possible. This technique offers freedom from contamination and precise control. High power electron guns are especially used for obtaining high evaporation rates for large area coatings. This paper deals with the coating experiments carried out on an indigenously developed high power strip electron gun with niobium as evaporant at 40 kW on S.S. substrate. The practical problems of conditioning the gun and venting the vacuum system after the high power operation are also discussed. The coating rate was calculated by weight difference method

Extremely deformable structures

CERN Document Server

2015-01-01

Recently, a new research stimulus has derived from the observation that soft structures, such as biological systems, but also rubber and gel, may work in a post critical regime, where elastic elements are subject to extreme deformations, though still exhibiting excellent mechanical performances. This is the realm of ‘extreme mechanics’, to which this book is addressed. The possibility of exploiting highly deformable structures opens new and unexpected technological possibilities. In particular, the challenge is the design of deformable and bi-stable mechanisms which can reach superior mechanical performances and can have a strong impact on several high-tech applications, including stretchable electronics, nanotube serpentines, deployable structures for aerospace engineering, cable deployment in the ocean, but also sensors and flexible actuators and vibration absorbers. Readers are introduced to a variety of interrelated topics involving the mechanics of extremely deformable structures, with emphasis on ...

Dry cooling with night cool storage to enhance solar power plants performance in extreme conditions areas

International Nuclear Information System (INIS)

Muñoz, J.; Martínez-Val, J.M.; Abbas, R.; Abánades, A.

2012-01-01

Highlights: ► Solar thermo-electric power plants with thermal storage for condenser cooling. ► Technology to mitigate the negative effect on Rankine cycles of the day-time high temperatures in deserts. ► Electricity production augmentation in demand-peak hours by the use of day-night temperature difference. -- Abstract: Solar thermal power plants are usually installed in locations with high yearly average solar radiation, often deserts. In such conditions, cooling water required for thermodynamic cycles is rarely available. Moreover, when solar radiation is high, ambient temperature is very high as well; this leads to excessive condensation temperature, especially when air-condensers are used, and decreases the plant efficiency. However, temperature variation in deserts is often very high, which drives to relatively low temperatures during the night. This fact can be exploited with the use of a closed cooling system, so that the coolant (water) is chilled during the night and store. Chilled water is then used during peak temperature hours to cool the condenser (dry cooling), thus enhancing power output and efficiency. The present work analyzes the performance improvement achieved by night thermal cool storage, compared to its equivalent air cooled power plant. Dry cooling is proved to be energy-effective for moderately high day–night temperature differences (20 °C), often found in desert locations. The storage volume requirement for different power plant efficiencies has also been studied, resulting on an asymptotic tendency.

High-power pre-chirp managed amplification of femtosecond pulses at high repetition rates

International Nuclear Information System (INIS)

Liu, Yang; Li, Wenxue; Zhao, Jian; Bai, Dongbi; Luo, Daping; Zeng, Heping

2015-01-01

Femtosecond pulses at 250 MHz repetition rate from a mode-locked fiber laser are amplified to high power in a pre-chirp managed amplifier. The experimental strategy offers a potential towards high-power ultrashort laser pulses at high repetition rates. By investigating the laser pulse evolution in the amplification processes, we show that self-similar evolution, finite gain bandwidth and mode instabilities determine pulse characteristics in different regimes. Further average power scaling is limited by the mode instabilities. Nevertheless, this laser system enables us to achieve sub-50 fs pulses with an average power of 93 W. (letter)

Effects of elevated mean and extremely high temperatures on the physio-ecological characteristics of geographically distinctive populations of Cunninghamia lanceolata

Science.gov (United States)

Zhou, Ting; Jia, Xiaorong; Liao, Huixuan; Peng, Shijia; Peng, Shaolin

2016-12-01

Conventional models for predicting species distribution under global warming scenarios often treat one species as a homogeneous whole. In the present study, we selected Cunninghamia lanceolata (C. lanceolata), a widely distributed species in China, to investigate the physio-ecological responses of five populations under different temperature regimes. The results demonstrate that increased mean temperatures induce increased growth performance among northern populations, which exhibited the greatest germination capacity and largest increase in the overlap between the growth curve and the monthly average temperature. However,tolerance of the southern population to extremely high temperatures was stronger than among the population from the northern region,shown by the best growth and the most stable photosynthetic system of the southern population under extremely high temperature. This result indicates that the growth advantage among northern populations due to increased mean temperatures may be weakened by lower tolerance to extremely high temperatures. This finding is antithetical to the predicted results. The theoretical coupling model constructed here illustrates that the difference in growth between populations at high and low latitudes and altitudes under global warming will decrease because of the frequent occurrence of extremely high temperatures.

ACIGA's high optical power test facility

International Nuclear Information System (INIS)

Ju, L; Aoun, M; Barriga, P

2004-01-01

Advanced laser interferometer detectors utilizing more than 100 W of laser power and with ∼10 6 W circulating laser power present many technological problems. The Australian Consortium for Interferometric Gravitational Astronomy (ACIGA) is developing a high power research facility in Gingin, north of Perth, Western Australia, which will test techniques for the next generation interferometers. In particular it will test thermal lensing compensation and control strategies for optical cavities in which optical spring effects and parametric instabilities may present major difficulties

Extremes temperatures and enthalpy in Finland and Sweden in a changing climate

International Nuclear Information System (INIS)

Venaelaeinen, A.; Saku, S.; Jylhae, K.; Nikulin, G.; Kjellstroem, E.; Baerring, L.

2009-06-01

Though risks caused by harsh weather conditions are taken into account in the planning of nuclear power plants, some exceptional weather events or combination of different events may prevent normal power operation and simultaneously endanger safe shutdown of the plant. Extreme weather events could influence, for example, the external power grid connection, emergency diesel generators (blockage of air intakes), ventilation and cooling of electric and electronics equipment rooms and the seawater intake. Due to the influence of an intensified greenhouse effect the climate is changing rapidly during the coming decades and this change is expected to have an influence also on the occurrence of extreme weather events. In this report we have examined extreme temperatures. Enthalpy is a parameter that combines air temperature and air humidity and it is used in the design of air conditioning systems. Therefore, we have included also return levels of enthalpy in our analysis. The influence of climate change on extreme temperatures is analysed based on regional climate model simulations. The reoccurrence times of high temperatures combined with high air humidity was analysed based on measurements made at five Finnish and three Swedish meteorological stations. Based on the observational records we find the 10 year return level of daily maximum temperature to be around 32 deg. C and the 100 year return level around 35 deg. C. If we look the return levels of warm and humid conditions then for example in Helsinki the 10 year return level of one week mean temperature in case mean air humidity is above 80% is 20.1 deg. C. The 10 year return level of daily maximum enthalpy is around 60 kJ/kg and the 100 year return level almost 70 kJ/kg. According to the climate model simulations the largest increase of 50-year return level of daily maximum temperature is found in southern Sweden and south-western Finland. By the end of this century the increase can be 3-5 deg. C. The largest change

Extremes temperatures and enthalpy in Finland and Sweden in a changing climate

Energy Technology Data Exchange (ETDEWEB)

Venaelaeinen, A.; Saku, S.; Jylhae, K. (Finnish Meteorological Institute (Finland)); Nikulin, G.; Kjellstroem, E.; Baerring, L. (Swedish Meteorological Institute (Sweden))

2009-06-15

Though risks caused by harsh weather conditions are taken into account in the planning of nuclear power plants, some exceptional weather events or combination of different events may prevent normal power operation and simultaneously endanger safe shutdown of the plant. Extreme weather events could influence, for example, the external power grid connection, emergency diesel generators (blockage of air intakes), ventilation and cooling of electric and electronics equipment rooms and the seawater intake. Due to the influence of an intensified greenhouse effect the climate is changing rapidly during the coming decades and this change is expected to have an influence also on the occurrence of extreme weather events. In this report we have examined extreme temperatures. Enthalpy is a parameter that combines air temperature and air humidity and it is used in the design of air conditioning systems. Therefore, we have included also return levels of enthalpy in our analysis. The influence of climate change on extreme temperatures is analysed based on regional climate model simulations. The reoccurrence times of high temperatures combined with high air humidity was analysed based on measurements made at five Finnish and three Swedish meteorological stations. Based on the observational records we find the 10 year return level of daily maximum temperature to be around 32 deg. C and the 100 year return level around 35 deg. C. If we look the return levels of warm and humid conditions then for example in Helsinki the 10 year return level of one week mean temperature in case mean air humidity is above 80% is 20.1 deg. C. The 10 year return level of daily maximum enthalpy is around 60 kJ/kg and the 100 year return level almost 70 kJ/kg. According to the climate model simulations the largest increase of 50-year return level of daily maximum temperature is found in southern Sweden and south-western Finland. By the end of this century the increase can be 3-5 deg. C. The largest change

High power all solid state VUV lasers

International Nuclear Information System (INIS)

Zhang, Shen-jin; Cui, Da-fu; Zhang, Feng-feng; Xu, Zhi; Wang, Zhi-min; Yang, Feng; Zong, Nan; Tu, Wei; Chen, Ying; Xu, Hong-yan; Xu, Feng-liang; Peng, Qin-jun; Wang, Xiao-yang; Chen, Chuang-tian; Xu, Zu-yan

2014-01-01

Highlights: • Polarization and pulse repetition rate adjustable ps 177.3 nm laser was developed. • Wavelength tunable ns, ps and fs VUV lasers were developed. • High power ns 177.3 nm laser with narrow linewidth was investigated. - Abstract: We report the investigation on the high power all solid state vacuum ultra-violet (VUV) lasers by means of nonlinear frequency conversion with KBe 2 BO 3 F 2 (KBBF) nonlinear crystal. Several all solid state VUV lasers have developed in our group, including polarization and pulse repetition rate adjustable picosecond 177.3 nm VUV laser, wavelength tunable nanosecond, picosecond and femtosecond VUV lasers, high power ns 177.3 nm laser with narrow linewidth. The VUV lasers have impact, accurate and precise advantage

Compact high-power terahertz radiation source

Directory of Open Access Journals (Sweden)

G. A. Krafft

2004-06-01

Full Text Available In this paper a new type of THz radiation source, based on recirculating an electron beam through a high gradient superconducting radio frequency cavity, and using this beam to drive a standard electromagnetic undulator on the return leg, is discussed. Because the beam is recirculated and not stored, short bunches may be produced that radiate coherently in the undulator, yielding exceptionally high average THz power for relatively low average beam power. Deceleration from the coherent emission, and the detuning it causes, limits the charge-per-bunch possible in such a device.

Predicting High-Power Performance in Professional Cyclists.

Science.gov (United States)

Sanders, Dajo; Heijboer, Mathieu; Akubat, Ibrahim; Meijer, Kenneth; Hesselink, Matthijs K

2017-03-01

To assess if short-duration (5 to ~300 s) high-power performance can accurately be predicted using the anaerobic power reserve (APR) model in professional cyclists. Data from 4 professional cyclists from a World Tour cycling team were used. Using the maximal aerobic power, sprint peak power output, and an exponential constant describing the decrement in power over time, a power-duration relationship was established for each participant. To test the predictive accuracy of the model, several all-out field trials of different durations were performed by each cyclist. The power output achieved during the all-out trials was compared with the predicted power output by the APR model. The power output predicted by the model showed very large to nearly perfect correlations to the actual power output obtained during the all-out trials for each cyclist (r = .88 ± .21, .92 ± .17, .95 ± .13, and .97 ± .09). Power output during the all-out trials remained within an average of 6.6% (53 W) of the predicted power output by the model. This preliminary pilot study presents 4 case studies on the applicability of the APR model in professional cyclists using a field-based approach. The decrement in all-out performance during high-intensity exercise seems to conform to a general relationship with a single exponential-decay model describing the decrement in power vs increasing duration. These results are in line with previous studies using the APR model to predict performance during brief all-out trials. Future research should evaluate the APR model with a larger sample size of elite cyclists.

Power Electronics

Indian Academy of Sciences (India)

They cover a wide spectrum of areas from power supplies to power system ... Ramanarayanan describe the modelling and design of a family of soft transition ... of power when the drive is operating in the braking mode and fast dynamic response. ... time models are extremely important, as they can be included in real time ...

Inverter design for high frequency power distribution

Science.gov (United States)

King, R. J.

1985-01-01

A class of simple resonantly commutated inverters are investigated for use in a high power (100 KW - 1000 KW) high frequency (10 KHz - 20 KHz) AC power distribution system. The Mapham inverter is found to provide a unique combination of large thyristor turn-off angle and good utilization factor, much better than an alternate 'current-fed' inverter. The effects of loading the Mapham inverter entirely with rectifier loads are investigated by simulation and with an experimental 3 KW 20 KHz inverter. This inverter is found to be well suited to a power system with heavy rectifier loading.

An Exit for the Human Product: A Comparative Study of Extreme Literature

Directory of Open Access Journals (Sweden)

Amelia Ying Qin

2014-04-01

Full Text Available This paper examines from a comparative perspective six novels telling stories of extreme life experiences set in both Western and oriental cultures. The paper argues that in these extreme cases, the characters, subjected to absolute power domination, lose their individual identities and are transformed into “human products.” Their struggles for power will always remain futile unless they find a way to reverse the power relationships they are trapped in. Such a reversal allows the hope of an exit for the “human products” to escape the hopeless situation of perpetuated social, sexual, and mental enslavement.

Reducing AC-Winding Losses in High-Current High-Power Inductors

DEFF Research Database (Denmark)

Nymand, Morten; Madawala, Udaya K.; Andersen, Michael Andreas E.

2009-01-01

Foil windings are preferable in high-current high-power inductors to realize compact designs and to reduce dc-current losses. At high frequency, however, proximity effect will cause very significant increase in ac resistance in multi-layer windings, and lead to high ac winding losses. This paper ...

Economic Justification of Concentrating Solar Power in High Renewable Energy Penetrated Power Systems

Energy Technology Data Exchange (ETDEWEB)

Hodge, Brian S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kroposki, Benjamin D [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Du, Ershun [Tsinghua University; Zhang, Ning [Tsinghua University; Kang, Chongqing [Tsinghua University; Xia, Qing [Tsinghua University

2018-04-24

Concentrating solar power (CSP) plants are able to provide both renewable energy and operational flexibility at the same time due to its thermal energy storage (TES). It is ideal generation to power systems lacking in flexibility to accommodate variable renewable energy (VRE) generation such as wind power and photovoltaics. However, its investment cost currently is too high to justify its benefit in terms of providing renewable energy only. In this paper we evaluate the economic benefit of CSP in high renewable energy penetrated power systems from two aspects: generating renewable energy and providing operational flexibility to help accommodating VRE. In order to keep the same renewable energy penetration level during evaluation, we compare the economic costs between the system with a high share of VRE and another in which some part of the VRE generation is replaced by CSP generation. The generation cost of a power system is analyzed through chronological operation simulation over a whole year. The benefit of CSP is quantified into two parts: (1) energy benefit - the saving investment of substituted VRE generation and (2) flexibility benefit - the reduction in operating cost due to substituting VRE with CSP. The break-even investment cost of CSP is further discussed. The methodology is tested on a modified IEEE RTS-79 system. The economic justifications of CSP are demonstrated in two practical provincial power systems with high penetration of renewable energy in northwestern China, Qinghai and Gansu, where the former province has massive inflexible thermal power plants but later one has high share of flexible hydro power. The results suggest that the CSP is more beneficial in Gansu system than in Qinghai. The levelized benefit of CSP, including both energy benefit and flexibility benefit, is about 0.177-0.191 $/kWh in Qinghai and about 0.238-0.300 $/kWh in Gansu, when replacing 5-20% VRE generation with CSP generation.

Extreme Environment High Temperature Communication Systems, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The purpose of this project is to develop and demonstrate a communications system capable of operation at extreme temperatures and pressures in hostile and corrosive...

Optimizing the design of very high power, high performance converters

International Nuclear Information System (INIS)

Edwards, R.J.; Tiagha, E.A.; Ganetis, G.; Nawrocky, R.J.

1980-01-01

This paper describes how various technologies are used to achieve the desired performance in a high current magnet power converter system. It is hoped that the discussions of the design approaches taken will be applicable to other power supply systems where stringent requirements in stability, accuracy and reliability must be met

Long-Term Reliability of a Hard-Switched Boost Power Processing Unit Utilizing SiC Power MOSFETs

Science.gov (United States)

Ikpe, Stanley A.; Lauenstein, Jean-Marie; Carr, Gregory A.; Hunter, Don; Ludwig, Lawrence L.; Wood, William; Iannello, Christopher J.; Del Castillo, Linda Y.; Fitzpatrick, Fred D.; Mojarradi, Mohammad M.;

High power density carbonate fuel cell

Energy Technology Data Exchange (ETDEWEB)

Yuh, C.; Johnsen, R.; Doyon, J.; Allen, J. [Energy Research Corp., Danbury, CT (United States)

1996-12-31

Carbonate fuel cell is a highly efficient and environmentally clean source of power generation. Many organizations worldwide are actively pursuing the development of the technology. Field demonstration of multi-MW size power plant has been initiated in 1996, a step toward commercialization before the turn of the century, Energy Research Corporation (ERC) is planning to introduce a 2.85MW commercial fuel cell power plant with an efficiency of 58%, which is quite attractive for distributed power generation. However, to further expand competitive edge over alternative systems and to achieve wider market penetration, ERC is exploring advanced carbonate fuel cells having significantly higher power densities. A more compact power plant would also stimulate interest in new markets such as ships and submarines where space limitations exist. The activities focused on reducing cell polarization and internal resistance as well as on advanced thin cell components.

Definitive intraoperative very high-dose radiotherapy for localized osteosarcoma in the extremities

International Nuclear Information System (INIS)

Oya, Natsuo; Kokubo, Masaki; Mizowaki, Takashi; Shibamoto, Yuta; Nagata, Yasushi; Sasai, Keisuke; Nishimura, Yasumasa; Tsuboyama, Tadao; Toguchida, Junya; Nakamura, Takashi; Hiraoka, Masahiro

2001-01-01

Purpose: To evaluate the outcome and adverse effects in patients with osteosarcoma treated with very high-dose definitive intraoperative radiotherapy (IORT), with the intention of saving the affected limb. Methods and Materials: Thirty-nine patients with osteosarcoma in their extremities were treated with definitive IORT. The irradiation field included the tumor plus an adequate wide margin and excluded the major vessels and nerves. Forty-five to 80 Gy of electrons or X-rays were delivered. The median follow-up of the surviving patients was 124 months. Results: The cause-specific and relapse-free 5-year survival rate was 50% and 43%, respectively. Distant metastasis developed in 23 patients; 19 died and 4 were alive for >10 years. Nine local recurrences were found 4-29 months after IORT in the affected limb. No radiation-induced skin reaction or nerve palsy was observed in the patients treated with X-rays. Experiments using phantoms also confirmed that the scatter dose was below the toxic level in the IORT setting with X-rays. Conclusions: Very high-dose definitive IORT combined with preventive nailing and chemotherapy appeared to be a promising quality-of-life-oriented alternative to treating patients with osteosarcomas in the extremities, although the problem of recurrences from the surrounding unirradiated soft tissue remains to be solved

Compact high voltage, high peak power, high frequency transformer for converter type modulator applications.

Science.gov (United States)

Reghu, T; Mandloi, V; Shrivastava, Purushottam

2016-04-01

The design and development of a compact high voltage, high peak power, high frequency transformer for a converter type modulator of klystron amplifiers is presented. The transformer has been designed to operate at a frequency of 20 kHz and at a flux swing of ±0.6 T. Iron (Fe) based nanocrystalline material has been selected as a core for the construction of the transformer. The transformer employs a specially designed solid Teflon bobbin having 120 kV insulation for winding the high voltage secondary windings. The flux swing of the core has been experimentally found by plotting the hysteresis loop at actual operating conditions. Based on the design, a prototype transformer has been built which is per se a unique combination of high voltage, high frequency, and peak power specifications. The transformer was able to provide 58 kV (pk-pk) at the secondary with a peak power handling capability of 700 kVA. The transformation ratio was 1:17. The performance of the transformer is also presented and discussed.

High Voltage Power Transmission for Wind Energy

Science.gov (United States)

Kim, Young il

The high wind speeds and wide available area at sea have recently increased the interests on offshore wind farms in the U.S.A. As offshore wind farms become larger and are placed further from the shore, the power transmission to the onshore grid becomes a key feature. Power transmission of the offshore wind farm, in which good wind conditions and a larger installation area than an onshore site are available, requires the use of submarine cable systems. Therefore, an underground power cable system requires unique design and installation challenges not found in the overhead power cable environment. This paper presents analysis about the benefit and drawbacks of three different transmission solutions: HVAC, LCC/VSC HVDC in the grid connecting offshore wind farms and also analyzed the electrical characteristics of underground cables. In particular, loss of HV (High Voltage) subsea power of the transmission cables was evaluated by the Brakelmann's theory, taking into account the distributions of current and temperature.

The influence of non thermal coherent EMR with low intensity and extremely high frequency on total activity and isoenzyme composition of peroxidase

International Nuclear Information System (INIS)

Nerkararyan, A.V.; Shahinyan, M.A.; Khachatryan, A.V.; Vardevanyan, P.O.

2011-01-01

In this work the influence of non-thermal coherent electromagnetic radiation (EMR) with low intensity and extremely high frequency on intensity of wheat developing germ metabolism has been investigated. Particularly, total activity and isoenzymatic composition of peroxidase of germ cells have been determined during their growth. The role of water in formation of organism response reaction to the external physical field effect has also been investigated. It has been shown, that water appears to be a primary element of extremely high frequency EMR effect on bio system. Extremely high frequency EMR irradiation of germinating seeds and the cultivation of dry seeds and their germs by irradiated water stimulate peroxidase synthesis in germ cells. The redistribution of quantitative composition of peroxidase molecular forms takes place in germ cells effected by EMR with extremely high frequency and low intensity

High-energy power capacitors, their applied technology and the trends

International Nuclear Information System (INIS)

2012-01-01

High-voltage and high-energy-density power capacitors called high-power ones such as film or electrolytic capacitors, have been used in large quantities for the pulse power technology such as an impulse current or voltage generator and a laser power supply, and for the power electronics one with progress of the power semiconductor device and the inverter technology. Recently, electric double layer capacitors (EDLC) with remarkable technical progress have been applied for the equipments of electric power and industrial field for the purpose of energy saving or electric power quality improvement, which have come to link to the electric power system. Thus, using a lot of high-power capacitors near our life would require to know the structure, the principle and the characteristic of capacitors, and also to consider suitable directions for use, maintenance and safety and so on, when carrying out a system and a facility design. In the technical report, while describing the dielectric and the feature of some high-power capacitors, and introducing the application examples to the laser-fusion power supply and some systems with EDLC, the trend of standardization of EDLC and the directivity of the examination about installation and maintenance of the applied equipments are described. (author)

Analysis of the Extremely Low Frequency Magnetic Field Emission from Laptop Computers

Directory of Open Access Journals (Sweden)

Brodić Darko

2016-03-01

Full Text Available This study addresses the problem of magnetic field emission produced by the laptop computers. Although, the magnetic field is spread over the entire frequency spectrum, the most dangerous part of it to the laptop users is the frequency range from 50 to 500 Hz, commonly called the extremely low frequency magnetic field. In this frequency region the magnetic field is characterized by high peak values. To examine the influence of laptop’s magnetic field emission in the office, a specific experiment is proposed. It includes the measurement of the magnetic field at six laptop’s positions, which are in close contact to its user. The results obtained from ten different laptop computers show the extremely high emission at some positions, which are dependent on the power dissipation or bad ergonomics. Eventually, the experiment extracts these dangerous positions of magnetic field emission and suggests possible solutions.

Improved cutting performance in high power laser cutting

DEFF Research Database (Denmark)

Olsen, Flemming Ove

2003-01-01

Recent results in high power laser cutting especially with focus on cutting of mild grade steel types for shipbuilding are described.......Recent results in high power laser cutting especially with focus on cutting of mild grade steel types for shipbuilding are described....

Total and Lower Extremity Lean Mass Percentage Positively Correlates With Jump Performance.

Science.gov (United States)

Stephenson, Mitchell L; Smith, Derek T; Heinbaugh, Erika M; Moynes, Rebecca C; Rockey, Shawn S; Thomas, Joi J; Dai, Boyi

2015-08-01

Strength and power have been identified as valuable components in both athletic performance and daily function. A major component of strength and power is the muscle mass, which can be assessed with dual-energy x-ray absorptiometry (DXA). The primary purpose of this study was to quantify the relationship between total body lean mass percentage (TBLM%) and lower extremity lean mass percentage (LELM%) and lower extremity force/power production during a countermovement jump (CMJ) in a general population. Researchers performed a DXA analysis on 40 younger participants aged 18-35 years, 28 middle-aged participants aged 36-55 years, and 34 older participants aged 56-75 years. Participants performed 3 CMJ on force platforms. Correlations revealed significant and strong relationships between TBLM% and LELM% compared with CMJ normalized peak vertical ground reaction force (p lean mass percentages. The findings have implications in including DXA-assessed lean mass percentage as a component for evaluating lower extremity strength and power. A paired DXA analysis and CMJ jump test may be useful for identifying neuromuscular deficits that limit performance.

Development of Highly Survivable Power and Communication System for NPP Instruments under Severe Accident

Energy Technology Data Exchange (ETDEWEB)

Yoo, Seung J.; Gu, Beom W.; Nguyen, Duy T.; Choi, Bo H.; Rim, Chun T. [KAIST, Daejeon (Korea, Republic of); Lee, So I. [KHNP CRI, Daejeon (Korea, Republic of)

2014-10-15

According to the detail report from the Fukushima nuclear accident, the failure of conventional instruments is mainly due to the following reasons. 1) Insufficient backup battery capacity after the station black out (SBO) 2) The malfunction or damage of instruments due to the extremely harsh ambient condition after the severe accident 3) The cut-off of power and communication cable due to the physical shocks of hydrogen explosion after the severe accident Since the current equipment qualification (EQ) for the NPP instruments is based on the design basis accident such as loss of coolant accident (LOCA), conventional instruments, which are examined under EQ condition, cannot guarantee their normal operation during the severe accident. A 7m-long-distance wireless power transfer and a radio frequency (RF) communication were introduced with conventional wired system to increase a redundancy. A heat isolation box and a harness are adopted to provide a protection from the expected physical shocks such as missiles and drastic increase of ambient temperature and pressure. A detail design principle of the highly survivable power and communication system, which has 4 sub-systems of a DCRS wireless power transfer, a Zigbee wireless communication, a GFRP harness, and a passive type router with a fly back regulator, has been presented in this paper. Each sub-system has been designed to have a robust operation characteristic regardless of the estimated physical shocks after the severe accident.

Development of Highly Survivable Power and Communication System for NPP Instruments under Severe Accident

International Nuclear Information System (INIS)

Yoo, Seung J.; Gu, Beom W.; Nguyen, Duy T.; Choi, Bo H.; Rim, Chun T.; Lee, So I.

2014-01-01

According to the detail report from the Fukushima nuclear accident, the failure of conventional instruments is mainly due to the following reasons. 1) Insufficient backup battery capacity after the station black out (SBO) 2) The malfunction or damage of instruments due to the extremely harsh ambient condition after the severe accident 3) The cut-off of power and communication cable due to the physical shocks of hydrogen explosion after the severe accident Since the current equipment qualification (EQ) for the NPP instruments is based on the design basis accident such as loss of coolant accident (LOCA), conventional instruments, which are examined under EQ condition, cannot guarantee their normal operation during the severe accident. A 7m-long-distance wireless power transfer and a radio frequency (RF) communication were introduced with conventional wired system to increase a redundancy. A heat isolation box and a harness are adopted to provide a protection from the expected physical shocks such as missiles and drastic increase of ambient temperature and pressure. A detail design principle of the highly survivable power and communication system, which has 4 sub-systems of a DCRS wireless power transfer, a Zigbee wireless communication, a GFRP harness, and a passive type router with a fly back regulator, has been presented in this paper. Each sub-system has been designed to have a robust operation characteristic regardless of the estimated physical shocks after the severe accident

The high-power iodine laser

Science.gov (United States)

Brederlow, G.; Fill, E.; Witte, K. J.

The book provides a description of the present state of the art concerning the iodine laser, giving particular attention to the design and operation of pulsed high-power iodine lasers. The basic features of the laser are examined, taking into account aspects of spontaneous emission lifetime, hyperfine structure, line broadening and line shifts, stimulated emission cross sections, the influence of magnetic fields, sublevel relaxation, the photodissociation of alkyl iodides, flashlamp technology, excitation in a direct discharge, chemical excitation, and questions regarding the chemical kinetics of the photodissociation iodine laser. The principles of high-power operation are considered along with aspects of beam quality and losses, the design and layout of an iodine laser system, the scalability and prospects of the iodine laser, and the design of the single-beam Asterix III laser.

Ultrasensitive, real-time trace gas detection using a high-power, multimode diode laser and cavity ringdown spectroscopy.

Science.gov (United States)

Karpf, Andreas; Qiao, Yuhao; Rao, Gottipaty N

2016-06-01

We present a simplified cavity ringdown (CRD) trace gas detection technique that is insensitive to vibration, and capable of extremely sensitive, real-time absorption measurements. A high-power, multimode Fabry-Perot (FP) diode laser with a broad wavelength range (Δλlaser∼0.6  nm) is used to excite a large number of cavity modes, thereby reducing the detector's susceptibility to vibration and making it well suited for field deployment. When detecting molecular species with broad absorption features (Δλabsorption≫Δλlaser), the laser's broad linewidth removes the need for precision wavelength stabilization. The laser's power and broad linewidth allow the use of on-axis cavity alignment, improving the signal-to-noise ratio while maintaining its vibration insensitivity. The use of an FP diode laser has the added advantages of being inexpensive, compact, and insensitive to vibration. The technique was demonstrated using a 1.1 W (λ=400  nm) diode laser to measure low concentrations of nitrogen dioxide (NO2) in zero air. A sensitivity of 38 parts in 1012 (ppt) was achieved using an integration time of 128 ms; for single-shot detection, 530 ppt sensitivity was demonstrated with a measurement time of 60 μs, which opens the door to sensitive measurements with extremely high temporal resolution; to the best of our knowledge, these are the highest speed measurements of NO2 concentration using CRD spectroscopy. The reduced susceptibility to vibration was demonstrated by introducing small vibrations into the apparatus and observing that there was no measurable effect on the sensitivity of detection.

Power supplyer for reactor coolant recycling pump

International Nuclear Information System (INIS)

Nara, Hiroshi; Okinaka, Yo.

1991-01-01

The present invention concerns a variable voltage/variable frequency static power source (static power source) used as a power source for a coolants recycling pump motor of a nuclear power plant. That is, during lower power operation such as start up or shutdown in which stoppage of the power source gives less effect to a reactor core, power is supplied from a power system, a main power generator connected thereto or a high voltage bus in the plant or a common high voltage bus to the static power source. However, during rated power operation, power is supplied from the output of an axially power generator connected with a main power generator having an extremely great inertia moment to the static power device. With such a constitution, the static power device is not stopped by the lowering of the voltage due to a thunderbolt falling accident or the like to a power-distribution line suddenly occurred in the power system. Accordingly, reactor core flowrate is free from rapid decrease caused by the reduction of rotation speed of the recycling pump. Accordingly, disadvantgages upon operation control in the reactor core is not caused. (I.S.)

Extremely low temperature properties of epoxy GFRP

International Nuclear Information System (INIS)

Kadotani, Kenzo; Nagai, Matao; Aki, Fumitake.

1983-01-01

The examination of fiber-reinforced plastics, that is, plastics such as epoxy, polyester and polyimide reinforced with high strength fibers such as glass, carbon, boron and steel, for extremely low temperature use began from the fuel tanks of rockets. Therafter, the trial manufacture of superconducting generators and extremely low temperature transformers and the manufacture of superconducting magnets for nuclear fusion experimental setups became active, and high performance FRPs have been adopted, of which the extremely low temperature properties have been sufficiently grasped. Recently, the cryostats made of FRPs have been developed, fully utilizing such features of FRPs as high strength, high rigidity, non-magnetic material, insulation, low heat conductivity, light weight and the freedom of molding. In this paper, the mechanical properties at extremely low temperature of the plastic composite materials used as insulators and structural materials for extremely low temperature superconducting equipment is outlined, and in particular, glass fiber-reinforced epoxy laminates are described somewhat in detail. The fracture strain of GFRP at extremely low temperature is about 1.3 times as large as that at room temperature, but at extremely low temperature, clear cracking occurred at 40% of the fracture strain. The linear thermal contraction of GFRP showed remarkable anisotropy. (Kako, I.)

Probing physics at extreme energies with cosmic ultra-high energy ...

Indian Academy of Sciences (India)

testing new particle physics. Keywords. Ultra-high ... conventional theories of CR origin based on acceleration of charged particles in powerful ... Before discussing specific scenarios for UHECR origin we give a short account of the numerical ...

GaN-based High Power High Frequency Wide Range LLC Resonant Converter, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — SET Group will design, build and demonstrate a Gallium Nitride (GaN) based High Power High Frequency Wide Range LLC Resonant Converter capable of handling high power...

In-volume heating using high-power laser diodes

NARCIS (Netherlands)

Denisenkov, V.S.; Kiyko, V.V.; Vdovin, G.V.

2015-01-01

High-power lasers are useful instruments suitable for applications in various fields; the most common industrial applications include cutting and welding. We propose a new application of high-power laser diodes as in-bulk heating source for food industry. Current heating processes use surface

Active Snubber Circuit for High Power Inverter Leg

DEFF Research Database (Denmark)

Rasmussen, Tonny Wederberg; Johansen, Morten Holst

2009-01-01

Abstract— High power converters in the conventional 6 pulse configuration with 6 switching elements IGBTs (Insulated Gate Bipolar Transistor) are pushed to the limit of power. Especially the switching loss is high. This reduces the switching frequency due to cooling problems. Passive snubber circ...

Extreme events in total ozone over Arosa – Part 1: Application of extreme value theory

Directory of Open Access Journals (Sweden)

H. E. Rieder

2010-10-01

Full Text Available In this study ideas from extreme value theory are for the first time applied in the field of stratospheric ozone research, because statistical analysis showed that previously used concepts assuming a Gaussian distribution (e.g. fixed deviations from mean values of total ozone data do not adequately address the structure of the extremes. We show that statistical extreme value methods are appropriate to identify ozone extremes and to describe the tails of the Arosa (Switzerland total ozone time series. In order to accommodate the seasonal cycle in total ozone, a daily moving threshold was determined and used, with tools from extreme value theory, to analyse the frequency of days with extreme low (termed ELOs and high (termed EHOs total ozone at Arosa. The analysis shows that the Generalized Pareto Distribution (GPD provides an appropriate model for the frequency distribution of total ozone above or below a mathematically well-defined threshold, thus providing a statistical description of ELOs and EHOs. The results show an increase in ELOs and a decrease in EHOs during the last decades. The fitted model represents the tails of the total ozone data set with high accuracy over the entire range (including absolute monthly minima and maxima, and enables a precise computation of the frequency distribution of ozone mini-holes (using constant thresholds. Analyzing the tails instead of a small fraction of days below constant thresholds provides deeper insight into the time series properties. Fingerprints of dynamical (e.g. ENSO, NAO and chemical features (e.g. strong polar vortex ozone loss, and major volcanic eruptions, can be identified in the observed frequency of extreme events throughout the time series. Overall the new approach to analysis of extremes provides more information on time series properties and variability than previous approaches that use only monthly averages and/or mini-holes and mini-highs.

Measurement of soft X-ray power from high-power Z-pinch plasma

International Nuclear Information System (INIS)

Wang Wensheng; Qiu Aici; Sun Fengrong; Luo Jianhui; Zhou Haisheng; He Duohui

2003-01-01

A Ni-film bolometer driven by the pulsed constant-voltage supply was developed for measuring soft X-ray energy under 1 keV generated from the Qiang-Guang-I, while the measuring system of the soft X-ray power was established with an X-ray diode detector. Results of the soft X-ray energy and power measurements were obtained at the experiment of Kr gas-puff high-power Z-pinch plasma

Modular High Voltage Power Supply

Energy Technology Data Exchange (ETDEWEB)

Newell, Matthew R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-05-18

The goal of this project is to develop a modular high voltage power supply that will meet the needs of safeguards applications and provide a modular plug and play supply for use with standard electronic racks.

Thulium heat source for high-endurance and high-energy density power systems

International Nuclear Information System (INIS)

Walter, C.E.; Kammeraad, J.E.; Van Konynenburg, R.; VanSant, J.H.

1991-05-01

We are studying the performance characteristics of radioisotope heat source designs for high-endurance and high-energy-density power systems that use thulium-170. Heat sources in the power range of 5--50 kW th coupled with a power conversion efficiency of ∼30%, can easily satisfy current missions for autonomous underwater vehicles. New naval missions will be possible because thulium isotope power systems have a factor of one-to-two hundred higher endurance and energy density than chemical and electrochemical systems. Thulium-170 also has several other attractive features, including the fact that it decays to stable ytterbium-170 with a half-life of four months. For terrestrial applications, refueling on that time scale should be acceptable in view of the advantage of its benign decay. The heat source designs we are studying account for the requirements of isotope production, shielding, and integration with power conversion components. These requirements are driven by environmental and safety considerations. Thulium is present in the form of thin refractory thulia disks that allow power conversion at high peak temperature. We give estimates of power system state points, performance, mass, and volume characteristics. Monte Carlo radiation analysis provides a detailed assessment of shield requirements and heat transfer under normal and distressed conditions is also considered. 11 refs., 7 figs., 4 tabs

High Power Density Motors

Science.gov (United States)

Kascak, Daniel J.

2004-01-01

With the growing concerns of global warming, the need for pollution-free vehicles is ever increasing. Pollution-free flight is one of NASA's goals for the 21" Century. , One method of approaching that goal is hydrogen-fueled aircraft that use fuel cells or turbo- generators to develop electric power that can drive electric motors that turn the aircraft's propulsive fans or propellers. Hydrogen fuel would likely be carried as a liquid, stored in tanks at its boiling point of 20.5 K (-422.5 F). Conventional electric motors, however, are far too heavy (for a given horsepower) to use on aircraft. Fortunately the liquid hydrogen fuel can provide essentially free refrigeration that can be used to cool the windings of motors before the hydrogen is used for fuel. Either High Temperature Superconductors (HTS) or high purity metals such as copper or aluminum may be used in the motor windings. Superconductors have essentially zero electrical resistance to steady current. The electrical resistance of high purity aluminum or copper near liquid hydrogen temperature can be l/lOO* or less of the room temperature resistance. These conductors could provide higher motor efficiency than normal room-temperature motors achieve. But much more importantly, these conductors can carry ten to a hundred times more current than copper conductors do in normal motors operating at room temperature. This is a consequence of the low electrical resistance and of good heat transfer coefficients in boiling LH2. Thus the conductors can produce higher magnetic field strengths and consequently higher motor torque and power. Designs, analysis and actual cryogenic motor tests show that such cryogenic motors could produce three or more times as much power per unit weight as turbine engines can, whereas conventional motors produce only 1/5 as much power per weight as turbine engines. This summer work has been done with Litz wire to maximize the current density. The current is limited by the amount of heat it

Welding with high power fiber lasers - A preliminary study

International Nuclear Information System (INIS)

Quintino, L.; Costa, A.; Miranda, R.; Yapp, D.; Kumar, V.; Kong, C.J.

2007-01-01

The new generation of high power fiber lasers presents several benefits for industrial purposes, namely high power with low beam divergence, flexible beam delivery, low maintenance costs, high efficiency and compact size. This paper presents a brief review of the development of high power lasers, and presents initial data on welding of API 5L: X100 pipeline steel with an 8 kW fiber laser. Weld bead geometry was evaluated and transition between conduction and deep penetration welding modes was investigated

Plasmonic nanocomposite thin film enabled fiber optic sensors for simultaneous gas and temperature sensing at extreme temperatures.

Science.gov (United States)

Ohodnicki, Paul R; Buric, Michael P; Brown, Thomas D; Matranga, Christopher; Wang, Congjun; Baltrus, John; Andio, Mark

2013-10-07

Embedded sensors capable of operation in extreme environments including high temperatures, high pressures, and highly reducing, oxidizing and/or corrosive environments can make a significant impact on enhanced efficiencies and reduced greenhouse gas emissions of current and future fossil-based power generation systems. Relevant technologies can also be leveraged in a wide range of other applications with similar needs including nuclear power generation, industrial process monitoring and control, and aviation/aerospace. Here we describe a novel approach to embedded sensing under extreme temperature conditions by integration of Au-nanoparticle based plasmonic nanocomposite thin films with optical fibers in an evanescent wave absorption spectroscopy configuration. Such sensors can potentially enable simultaneous temperature and gas sensing at temperatures approaching 900-1000 °C in a manner compatible with embedded and distributed sensing approaches. The approach is demonstrated using the Au/SiO2 system deposited on silica-based optical fibers. Stability of optical fibers under relevant high temperature conditions and interactions with changing ambient gas atmospheres is an area requiring additional investigation and development but the simplicity of the sensor design makes it potentially cost-effective and may offer a potential for widespread deployment.

Very High Frequency Switch-Mode Power Supplies

DEFF Research Database (Denmark)

Madsen, Mickey Pierre

The importance of technology and electronics in our daily life is constantly increasing. At the same time portability and energy efficiency are currently some of the hottest topics. This creates a huge need for power converters in a compact form factor and with high efficiency, which can supply...... these electronic devices. This calls for new technologies in order to miniaturize the power electronics of today. One way to do this is by increasing the switching frequency dramatically and develop very high frequency switch mode power supplies. If these converters can be designed to operate efficiently, a huge...... size, weight and cost reduction can be achieved due to the smaller energy storing elements needed at these frequencies. The research presented in this thesis focuses on exactly this. First various technologies for miniaturization of power supplies are studied, e.g. piezo electric transformers, wide...

Social power and recognition of emotional prosody: High power is associated with lower recognition accuracy than low power.

Science.gov (United States)

Uskul, Ayse K; Paulmann, Silke; Weick, Mario

2016-02-01

Listeners have to pay close attention to a speaker's tone of voice (prosody) during daily conversations. This is particularly important when trying to infer the emotional state of the speaker. Although a growing body of research has explored how emotions are processed from speech in general, little is known about how psychosocial factors such as social power can shape the perception of vocal emotional attributes. Thus, the present studies explored how social power affects emotional prosody recognition. In a correlational study (Study 1) and an experimental study (Study 2), we show that high power is associated with lower accuracy in emotional prosody recognition than low power. These results, for the first time, suggest that individuals experiencing high or low power perceive emotional tone of voice differently. (c) 2016 APA, all rights reserved).

Probabilistic Wind Power Forecasting with Hybrid Artificial Neural Networks

DEFF Research Database (Denmark)

Wan, Can; Song, Yonghua; Xu, Zhao

2016-01-01

probabilities of prediction errors provide an alternative yet effective solution. This article proposes a hybrid artificial neural network approach to generate prediction intervals of wind power. An extreme learning machine is applied to conduct point prediction of wind power and estimate model uncertainties...... via a bootstrap technique. Subsequently, the maximum likelihood estimation method is employed to construct a distinct neural network to estimate the noise variance of forecasting results. The proposed approach has been tested on multi-step forecasting of high-resolution (10-min) wind power using...... actual wind power data from Denmark. The numerical results demonstrate that the proposed hybrid artificial neural network approach is effective and efficient for probabilistic forecasting of wind power and has high potential in practical applications....

Study of novel plasma devices generated by high power lasers coupled with a micro-pulse power technology

International Nuclear Information System (INIS)

Nishida, A; Chen, Z L; Jin, Z; Kondo, K; Nakagawa, M; Kodama, R; Arima, H; Yoneda, H

2008-01-01

The authors have proposed introducing a micro pulse power technology in high power laser plasma experiments to boost up the return current, resulting in efficiently guiding of energetic electrons. High current pulse power generators with a pulse laser trigger system generate high-density plasma that is well conductor. To efficiently guiding by using a micro pulse power, we estimated parameter of a micro pulse power system that is voltage of rise time, current, charging voltage and capacitance

CLASH: EXTREME EMISSION-LINE GALAXIES AND THEIR IMPLICATION ON SELECTION OF HIGH-REDSHIFT GALAXIES

International Nuclear Information System (INIS)

Huang, Xingxing; Wang, Junxian; Shu, Xinwen; Zheng, Wei; Ford, Holland; Lemze, Doron; Moustakas, John; Van der Wel, Arjen; Zitrin, Adi; Frye, Brenda L.; Postman, Marc; Bradley, Larry; Coe, Dan; Bartelmann, Matthias; Benítez, Narciso; Broadhurst, Tom; Donahue, Megan; Infante, Leopoldo

2015-01-01

We utilize the Cluster Lensing And Supernova survey with Hubble observations of 25 clusters to search for extreme emission-line galaxies (EELGs). The selections are carried out in two central bands: F105W (Y 105 ) and F125W (J 125 ), as the flux of the central bands could be enhanced by the presence of [O III] λλ4959, 5007 at redshifts of ∼0.93-1.14 and 1.57-1.79, respectively. The multiband observations help to constrain the equivalent widths (EWs) of emission lines. Thanks to cluster lensing, we are able to identify 52 candidates down to an intrinsic limiting magnitude of 28.5 and to a rest-frame [O III] λλ4959, 5007 EW of ≅ 3700 Å. Our samples include a number of EELGs at lower luminosities that are missed in other surveys, and the extremely high EW can only be found in such faint galaxies. These EELGs can mimic a dropout feature similar to that of high-redshift galaxies and contaminate the color-color selection of high-redshift galaxies when the signal-to-noise ratio is limited or the band coverage is incomplete

CLASH: EXTREME EMISSION-LINE GALAXIES AND THEIR IMPLICATION ON SELECTION OF HIGH-REDSHIFT GALAXIES

Energy Technology Data Exchange (ETDEWEB)

Huang, Xingxing; Wang, Junxian; Shu, Xinwen [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zheng, Wei; Ford, Holland; Lemze, Doron [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Moustakas, John [Department of Physics and Astronomy, Siena College, 515 Loudon Road, Loudonville, NY 12211 (United States); Van der Wel, Arjen [Max-Planck Institute for Astronomy, Königstuhl 17, D-69117, Heidelberg (Germany); Zitrin, Adi [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States); Frye, Brenda L. [Steward Observatory/Department of Astronomy, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States); Postman, Marc; Bradley, Larry; Coe, Dan [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21208 (United States); Bartelmann, Matthias [Leiden Observatory, Leiden University, P. O. Box 9513, 2300 RA Leiden (Netherlands); Benítez, Narciso [Instituto de Astrofísica de Andalucía (CSIC), C/Camino Bajo de Huétor 24, Granada E-18008 (Spain); Broadhurst, Tom [Department of Theoretical Physics, University of Basque Country UPV/EHU E-Bilbao (Spain); Donahue, Megan [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Infante, Leopoldo, E-mail: hxx@mail.ustc.edu.cn [Departamento de Astronoía y Astrofísica, Pontificia Universidad Católica de Chile, V. Mackenna 4860 Santiago 22 (Chile); and others

2015-03-01

We utilize the Cluster Lensing And Supernova survey with Hubble observations of 25 clusters to search for extreme emission-line galaxies (EELGs). The selections are carried out in two central bands: F105W (Y {sub 105}) and F125W (J {sub 125}), as the flux of the central bands could be enhanced by the presence of [O III] λλ4959, 5007 at redshifts of ∼0.93-1.14 and 1.57-1.79, respectively. The multiband observations help to constrain the equivalent widths (EWs) of emission lines. Thanks to cluster lensing, we are able to identify 52 candidates down to an intrinsic limiting magnitude of 28.5 and to a rest-frame [O III] λλ4959, 5007 EW of ≅ 3700 Å. Our samples include a number of EELGs at lower luminosities that are missed in other surveys, and the extremely high EW can only be found in such faint galaxies. These EELGs can mimic a dropout feature similar to that of high-redshift galaxies and contaminate the color-color selection of high-redshift galaxies when the signal-to-noise ratio is limited or the band coverage is incomplete.

Protection and safety of nuclear power stations

International Nuclear Information System (INIS)

Anon.

1976-01-01

The extreme requirements for the safety of nuclear power stations set tasks to the civil engineer which, resulting from dynamic load assumptions, among other things also demand the development of novel special concrete steels with a high elastic limit (here: DYWIDAG thread tie rod) for singly reinforced members. (orig.) [de

An Extreme Meteorological Events Analysis For Nuclear Power Plant (NPP) Siting Project at Bangka Island, Indonesia

Science.gov (United States)

Septiadi, Deni; S, Yarianto Sugeng B.; Sriyana; Anzhar, Kurnia; Suntoko, Hadi

2018-03-01

The potential sources of meteorological phenomena in Nuclear Power Plant (NPP) area of interest are identified and the extreme values of the possible resulting hazards associated which such phenomena are evaluated to derive the appropriate design bases for the NPP. The appropriate design bases shall be determined according to the Nuclear Energy Regulatory Agency (Bapeten) applicable regulations, which presently do not indicate quantitative criteria for purposes of determining the design bases for meteorological hazards. These meteorological investigations are also carried out to evaluate the regional and site specific meteorological parameters which affect the transport and dispersion of radioactive effluents on the environment of the region around the NPP site. The meteorological hazards are to be monitored and assessed periodically over the lifetime of the plant to ensure that consistency with the design assumptions is maintained throughout the full lifetime of the facility.

Local likelihood estimation of complex tail dependence structures in high dimensions, applied to US precipitation extremes

KAUST Repository

Camilo, Daniela Castro

2017-10-02

In order to model the complex non-stationary dependence structure of precipitation extremes over the entire contiguous U.S., we propose a flexible local approach based on factor copula models. Our sub-asymptotic spatial modeling framework yields non-trivial tail dependence structures, with a weakening dependence strength as events become more extreme, a feature commonly observed with precipitation data but not accounted for in classical asymptotic extreme-value models. To estimate the local extremal behavior, we fit the proposed model in small regional neighborhoods to high threshold exceedances, under the assumption of local stationarity. This allows us to gain in flexibility, while making inference for such a large and complex dataset feasible. Adopting a local censored likelihood approach, inference is made on a fine spatial grid, and local estimation is performed taking advantage of distributed computing resources and of the embarrassingly parallel nature of this estimation procedure. The local model is efficiently fitted at all grid points, and uncertainty is measured using a block bootstrap procedure. An extensive simulation study shows that our approach is able to adequately capture complex, non-stationary dependencies, while our study of U.S. winter precipitation data reveals interesting differences in local tail structures over space, which has important implications on regional risk assessment of extreme precipitation events. A comparison between past and current data suggests that extremes in certain areas might be slightly wider in extent nowadays than during the first half of the twentieth century.

Local likelihood estimation of complex tail dependence structures in high dimensions, applied to US precipitation extremes

KAUST Repository

Camilo, Daniela Castro; Huser, Raphaë l

2017-01-01

In order to model the complex non-stationary dependence structure of precipitation extremes over the entire contiguous U.S., we propose a flexible local approach based on factor copula models. Our sub-asymptotic spatial modeling framework yields non-trivial tail dependence structures, with a weakening dependence strength as events become more extreme, a feature commonly observed with precipitation data but not accounted for in classical asymptotic extreme-value models. To estimate the local extremal behavior, we fit the proposed model in small regional neighborhoods to high threshold exceedances, under the assumption of local stationarity. This allows us to gain in flexibility, while making inference for such a large and complex dataset feasible. Adopting a local censored likelihood approach, inference is made on a fine spatial grid, and local estimation is performed taking advantage of distributed computing resources and of the embarrassingly parallel nature of this estimation procedure. The local model is efficiently fitted at all grid points, and uncertainty is measured using a block bootstrap procedure. An extensive simulation study shows that our approach is able to adequately capture complex, non-stationary dependencies, while our study of U.S. winter precipitation data reveals interesting differences in local tail structures over space, which has important implications on regional risk assessment of extreme precipitation events. A comparison between past and current data suggests that extremes in certain areas might be slightly wider in extent nowadays than during the first half of the twentieth century.

Nitrogen accumulation and partitioning in a High Arctic tundra ecosystem from extreme atmospheric N deposition events

International Nuclear Information System (INIS)

Choudhary, Sonal; Blaud, Aimeric; Osborn, A. Mark; Press, Malcolm C.; Phoenix, Gareth K.

2016-01-01

Arctic ecosystems are threatened by pollution from recently detected extreme atmospheric nitrogen (N) deposition events in which up to 90% of the annual N deposition can occur in just a few days. We undertook the first assessment of the fate of N from extreme deposition in High Arctic tundra and are presenting the results from the whole ecosystem "1"5N labelling experiment. In 2010, we simulated N depositions at rates of 0, 0.04, 0.4 and 1.2 g N m"−"2 yr"−"1, applied as "1"5NH_4"1"5NO_3 in Svalbard (79"°N), during the summer. Separate applications of "1"5NO_3"− and "1"5NH_4"+ were also made to determine the importance of N form in their retention. More than 95% of the total "1"5N applied was recovered after one growing season (~ 90% after two), demonstrating a considerable capacity of Arctic tundra to retain N from these deposition events. Important sinks for the deposited N, regardless of its application rate or form, were non-vascular plants > vascular plants > organic soil > litter > mineral soil, suggesting that non-vascular plants could be the primary component of this ecosystem to undergo measurable changes due to N enrichment from extreme deposition events. Substantial retention of N by soil microbial biomass (70% and 39% of "1"5N in organic and mineral horizon, respectively) during the initial partitioning demonstrated their capacity to act as effective buffers for N leaching. Between the two N forms, vascular plants (Salix polaris) in particular showed difference in their N recovery, incorporating four times greater "1"5NO_3"− than "1"5NH_4"+, suggesting deposition rich in nitrate will impact them more. Overall, these findings show that despite the deposition rates being extreme in statistical terms, biologically they do not exceed the capacity of tundra to sequester pollutant N during the growing season. Therefore, current and future extreme events may represent a major source of eutrophication. - Highlights: • High Arctic tundra demonstrated a

Extreme ultraviolet spectroscopy of highly charged argon ions at the Berlin EBIT

International Nuclear Information System (INIS)

Biedermann, C; Radtke, R; Fussmann, G; Allen, F I

2007-01-01

Extreme ultraviolet radiation from highly charged argon was investigated at the Berlin Electron Beam Ion Trap with a 2 m grazing incidence spectrometer. Lines in the wavelength range 150 to 660 A originating from C-like Ar 12+ to Li-like Ar 15+ ions have been identified and are compared with database information from solar line lists and predictions. Line ratios for the observed resonance, intercombination and forbidden lines offer important diagnostic capabilities for low density, hot plasmas

High-power electronics

CERN Document Server

Kapitsa, Petr Leonidovich

1966-01-01

High-Power Electronics, Volume 2 presents the electronic processes in devices of the magnetron type and electromagnetic oscillations in different systems. This book explores the problems of electronic energetics.Organized into 11 chapters, this volume begins with an overview of the motion of electrons in a flat model of the magnetron, taking into account the in-phase wave and the reverse wave. This text then examines the processes of transmission of electromagnetic waves of various polarization and the wave reflection from grids made of periodically distributed infinite metal conductors. Other

Design methods for high temperature power plant structures

International Nuclear Information System (INIS)

Townley, C.H.A.

1984-01-01

The subject is discussed under the headings: introduction (scope of paper - reviews of design methods and design criteria currently in use for both nuclear and fossil fuelled power plant; examples chosen are (a) BS 1113, representative of design codes employed for power station boiler plant; (b) ASME Code Case N47, which is being developed for high temperature nuclear reactors, especially the liquid metal fast breeder reactor); design codes for power station boilers; Code Case N47 (design in the absence of thermal shock and thermal fatigue; design against cyclic loading at high temperature; further research in support of high temperature design methods and criteria for LMFBRs); concluding remarks. (U.K.)

High performance protection circuit for power electronics applications

Energy Technology Data Exchange (ETDEWEB)

Tudoran, Cristian D., E-mail: cristian.tudoran@itim-cj.ro; Dădârlat, Dorin N.; Toşa, Nicoleta; Mişan, Ioan [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat, PO 5 Box 700, 400293 Cluj-Napoca (Romania)

2015-12-23

In this paper we present a high performance protection circuit designed for the power electronics applications where the load currents can increase rapidly and exceed the maximum allowed values, like in the case of high frequency induction heating inverters or high frequency plasma generators. The protection circuit is based on a microcontroller and can be adapted for use on single-phase or three-phase power systems. Its versatility comes from the fact that the circuit can communicate with the protected system, having the role of a “sensor” or it can interrupt the power supply for protection, in this case functioning as an external, independent protection circuit.

Preliminary design of high-power wave-guide/transmission system

Indian Academy of Sciences (India)

... CW klystron followed by wave-guide filter, dual directional coupler, high-power circulator, three 3 dB magic TEE power dividers to split the main channel into four equal channels of 250 kW each. Each individual channel has dual directional couplers, flexible wave-guide sections and high power ceramic vacuum window.

High technology supporting nuclear power industry in CRIEPI

International Nuclear Information System (INIS)

Ueda, Nobuyuki

2009-01-01

As a central research institute of electric power industry, Central Research Institute of Electric Power Industry (CRIEPI) has carried out R and D on broad range of topics such as power generation, power transmission, power distribution, power application and energy economics and society, aiming to develop prospective and advanced technologies, fundamental reinforce technologies and next-generation core technologies. To realize low-carbon society to cope with enhancement of global environmental issues, nuclear power is highly recommended as large-scale power with low-carbon emission. At the new start of serial explanation on advanced technologies, R and D on electric power industry was outlined. (T. Tanaka)

Development and advances in conventional high power RF systems

International Nuclear Information System (INIS)

Wilson, P.B.

1995-06-01

The development of rf systems capable of producing high peak power (hundreds of megawatts) at relatively short pulse lengths (0.1--5 microseconds) is currently being driven mainly by the requirements of future high energy linear colliders, although there may be applications to industrial, medical and research linacs as well. The production of high peak power rf typically involves four basic elements: a power supply to convert ac from the ''wall plug'' to dc; a modulator, or some sort of switching element, to produce pulsed dc power; an rf source to convert the pulsed dc to pulsed rf power; and possibly an rf pulse compression system to further enhance the peak rf power. Each element in this rf chain from wall plug to accelerating structure must perform with high efficiency in a linear collider application, such that the overall system efficiency is 30% or more. Basic design concepts are discussed for klystrons, modulators and rf pulse compression systems, and their present design status is summarized for applications to proposed linear colliders

Industrial applications of high-average power high-peak power nanosecond pulse duration Nd:YAG lasers

Science.gov (United States)

Harrison, Paul M.; Ellwi, Samir

2009-02-01

Within the vast range of laser materials processing applications, every type of successful commercial laser has been driven by a major industrial process. For high average power, high peak power, nanosecond pulse duration Nd:YAG DPSS lasers, the enabling process is high speed surface engineering. This includes applications such as thin film patterning and selective coating removal in markets such as the flat panel displays (FPD), solar and automotive industries. Applications such as these tend to require working spots that have uniform intensity distribution using specific shapes and dimensions, so a range of innovative beam delivery systems have been developed that convert the gaussian beam shape produced by the laser into a range of rectangular and/or shaped spots, as required by demands of each project. In this paper the authors will discuss the key parameters of this type of laser and examine why they are important for high speed surface engineering projects, and how they affect the underlying laser-material interaction and the removal mechanism. Several case studies will be considered in the FPD and solar markets, exploring the close link between the application, the key laser characteristics and the beam delivery system that link these together.

Cascade: a high-efficiency ICF power reactor

International Nuclear Information System (INIS)

Pitts, J.H.

1985-01-01

Cascade attains a net power-plant efficiency of 49% and its cost is competitive with high-temperature gas-cooled reactor, pressurized-water reactor, and coal-fired power plants. The Cascade reactor and blanket are made of ceramic materials and activation is 6 times less than that of the MARS Tandem Mirror Reactor operating at comparable power. Hands-on maintenance of the heat exchangers is possible one day after shutdown. Essentially all tritium is recovered in the vacuum system, with the remainder recovered from the helium power conversion loop. Tritium leakage external to the vacuum system and power conversion loop is only 0.03 Ci/d

Nuclear power plant Olkiluoto 3. Containment leakage test under extreme conditions

Energy Technology Data Exchange (ETDEWEB)

Fleckenstein, Tobias [TUEV SUED Industrie Service GmbH, Munich (Germany). Measaruement Technology Dept.

2015-01-15

Modern nuclear power plants place high demands on the design and execution of safety checks. TUEV SUED supported the containment leakage test for the largest- capacity third generation nuclear power plant in the world - Olkiluoto 3 in Finland. The experts successfully met the challenges presented by exceptional parameters of the project. The containment of Olkiluoto 3 is unique in that the vessel's volume is 80,000 m{sup 3} while measurements were carried out over a period of ten days. To execute the test, 75 temperature and 15 humidity sensors had to be installed and correctly interlinked by more than ten kilometres of cable. These instruments also needed to withstand an absolute pressure of 6 bar, ambient temperatures of 30 C and high levels of humidity. These conditions required comprehensive preparation and a high amount of qualification tests. Parts of the qualifications were carried out at the autoclave system of the Technical University in Munich, Germany, where the project test conditions could be simulated. The software required to determine the tests was developed by TUEV SUED and verified by German's national accreditation body DAkkS under ISO 17025. TUEV SUED enabled the test schedule to continue without delay by analysing all recorded data continuously on site, including pressure, temperature, humidity and leakage mass flow curves. With the comprehensive preparation, data acquisition system recording measurements continuously and the on-time result calculation, all components of the leak-tightness assessment were successfully completed in accordance with requirements.

High power rf component testing for the NLC

International Nuclear Information System (INIS)

Vlieks, A.E.; Fowkes, W.R.; Loewen, R.J.; Tantawi, S.G.

1998-09-01

In the Next Linear Collider (NLC), the high power rf components must be capable of handling peak rf power levels in excess of 600 MW. In the current view of the NLC, even the rectangular waveguide components must transmit at least 300 MW rf power. At this power level, peak rf fields can greatly exceed 100 MV/m. The authors present recent results of high power tests performed at the Accelerator Structure Test Area (ASTA) at SLAC. These tests are designed to investigate the rf breakdown limits of several new components potentially useful for the NLC. In particular, the authors tested a new TE 01 --TE 10 circular to rectangular wrap-around mode converter, a modified (internal fin) Magic Tee hybrid, and an upgraded flower petal mode converter

Mechanisms of joint and microstructure formation in high power ultrasonic spot welding 6111 aluminium automotive sheet

International Nuclear Information System (INIS)

Bakavos, D.; Prangnell, P.B.

2010-01-01

Resistance spot welding (RSW) is difficult to apply to aluminium automotive alloys. High power ultrasonic spot welding (HP-USW) is a new alternative method which is extremely efficient, using ∼2% of the energy of RSW. However, to date there have been few studies of the mechanisms of bond formation and the material interactions that take place with this process. Here, we report on a detailed investigation where we have used X-ray tomography, high resolution SEM, and EBSD, and dissimilar alloy welds, to track the interface position and characterise the stages of weld formation, and microstructure evolution, as a function of welding energy. Under optimum conditions high quality welds are produced, showing few defects. Welding proceeds by the development and spread of microwelds, until extensive plastic deformation occurs within the weld zone, where the temperature reaches ∼380 deg. C. The origin of the weld interface 'flow features' characteristic of HP-USW are discussed.

High power coaxial ubitron

Science.gov (United States)

Balkcum, Adam J.

In the ubitron, also known as the free electron laser, high power coherent radiation is generated from the interaction of an undulating electron beam with an electromagnetic signal and a static periodic magnetic wiggler field. These devices have experimentally produced high power spanning the microwave to x-ray regimes. Potential applications range from microwave radar to the study of solid state material properties. In this dissertation, the efficient production of high power microwaves (HPM) is investigated for a ubitron employing a coaxial circuit and wiggler. Designs for the particular applications of an advanced high gradient linear accelerator driver and a directed energy source are presented. The coaxial ubitron is inherently suited for the production of HPM. It utilizes an annular electron beam to drive the low loss, RF breakdown resistant TE01 mode of a large coaxial circuit. The device's large cross-sectional area greatly reduces RF wall heat loading and the current density loading at the cathode required to produce the moderate energy (500 keV) but high current (1-10 kA) annular electron beam. Focusing and wiggling of the beam is achieved using coaxial annular periodic permanent magnet (PPM) stacks without a solenoidal guide magnetic field. This wiggler configuration is compact, efficient and can propagate the multi-kiloampere electron beams required for many HPM applications. The coaxial PPM ubitron in a traveling wave amplifier, cavity oscillator and klystron configuration is investigated using linear theory and simulation codes. A condition for the dc electron beam stability in the coaxial wiggler is derived and verified using the 2-1/2 dimensional particle-in-cell code, MAGIC. New linear theories for the cavity start-oscillation current and gain in a klystron are derived. A self-consistent nonlinear theory for the ubitron-TWT and a new nonlinear theory for the ubitron oscillator are presented. These form the basis for simulation codes which, along

The opposite end of the attention deficit hyperactivity disorder continuum: genetic and environmental aetiologies of extremely low ADHD traits.

Science.gov (United States)

Greven, Corina U; Merwood, Andrew; van der Meer, Jolanda M J; Haworth, Claire M A; Rommelse, Nanda; Buitelaar, Jan K

2016-04-01