Seneca Compressed Air Energy Storage (CAES) Project
Energy Technology Data Exchange (ETDEWEB)
None, None
2012-11-30
Compressed Air Energy Storage (CAES) is a hybrid energy storage and generation concept that has many potential benefits especially in a location with increasing percentages of intermittent wind energy generation. The objectives of the NYSEG Seneca CAES Project included: for Phase 1, development of a Front End Engineering Design for a 130MW to 210 MW utility-owned facility including capital costs; project financials based on the engineering design and forecasts of energy market revenues; design of the salt cavern to be used for air storage; draft environmental permit filings; and draft NYISO interconnection filing; for Phase 2, objectives included plant construction with a target in-service date of mid-2016; and for Phase 3, objectives included commercial demonstration, testing, and two-years of performance reporting. This Final Report is presented now at the end of Phase 1 because NYSEG has concluded that the economics of the project are not favorable for development in the current economic environment in New York State. The proposed site is located in NYSEG’s service territory in the Town of Reading, New York, at the southern end of Seneca Lake, in New York State’s Finger Lakes region. The landowner of the proposed site is Inergy, a company that owns the salt solution mining facility at this property. Inergy would have developed a new air storage cavern facility to be designed for NYSEG specifically for the Seneca CAES project. A large volume, natural gas storage facility owned and operated by Inergy is also located near this site and would have provided a source of high pressure pipeline quality natural gas for use in the CAES plant. The site has an electrical take-away capability of 210 MW via two NYSEG 115 kV circuits located approximately one half mile from the plant site. Cooling tower make-up water would have been supplied from Seneca Lake. NYSEG’s engineering consultant WorleyParsons Group thoroughly evaluated three CAES designs and concluded that any
Future perspectives on automotive CAE
Bensler, Henry; Eller, Tom; Kabat vel Job, Alexander; Magoulas, Nikolaos; Yigit, Emrah; Van Tongeren, A.
2014-01-01
Computer Aided Engineering (CAE) is an integral part of today’s automotive design process. Very often OEM’s rely solely on software vendors to provide appropriate solutions. On the other hand, some companies still use in-house developed software for specific applications. It is, however, a
Acoustic performance of industrial mufflers with CAE modeling and simulation
Directory of Open Access Journals (Sweden)
Jeon Soohong
2014-12-01
Full Text Available This paper investigates the noise transmission performance of industrial mufflers widely used in ships based on the CAE modeling and simulation. Since the industrial mufflers have very complicated internal structures, the conventional Transfer Matrix Method (TMM is of limited use. The CAE modeling and simulation is therefore required to incorporate commercial softwares: CATIA for geometry modeling, MSC/PATRAN for FE meshing and LMS/ SYSNOISE for analysis. Main sources of difficulties in this study are led by complicated arrangement of reactive elements, perforated walls and absorption materials. The reactive elements and absorbent materials are modeled by applying boundary conditions given by impedance. The perforated walls are modeled by applying the transfer impedance on the duplicated node mesh. The CAE approach presented in this paper is verified by comparing with the theoretical solution of a concentric-tube resonator and is applied for industrial mufflers.
Acoustic performance of industrial mufflers with CAE modeling and simulation
Directory of Open Access Journals (Sweden)
Soohong Jeon
2014-12-01
Full Text Available This paper investigates the noise transmission performance of industrial mufflers widely used in ships based on the CAE modeling and simulation. Since the industrial mufflers have very complicated internal structures, the conventional Transfer Matrix Method (TMM is of limited use. The CAE modeling and simulation is therefore required to incorporate commercial softwares: CATIA for geometry modeling, MSC/PATRAN for FE meshing and LMS/SYSNOISE for analysis. Main sources of difficulties in this study are led by complicated arrangement of reactive ele- ments, perforated walls and absorption materials. The reactive elements and absorbent materials are modeled by applying boundary conditions given by impedance. The perforated walls are modeled by applying the transfer impedance on the duplicated node mesh. The CAE approach presented in this paper is verified by comparing with the theoretical solution of a concentric-tube resonator and is applied for industrial mufflers.
TOSHIBA CAE system for nuclear power plant
International Nuclear Information System (INIS)
Machiba, Hiroshi; Sasaki, Norio
1990-01-01
TOSHIBA aims to secure safety, increase reliability and improve efficiency through the engineering for nuclear power plant using Computer Aided Engineering (CAE). TOSHIBA CAE system for nuclear power plant consists of numbers of sub-systems which had been integrated centering around the Nuclear Power Plant Engineering Data Base (PDBMS) and covers all stage of engineering for nuclear power plant from project management, design, manufacturing, construction to operating plant service and preventive maintenance as it were 'Plant Life-Cycle CAE System'. In recent years, TOSHIBA has been devoting to extend the system for integrated intelligent CAE system with state-of-the-art computer technologies such as computer graphics and artificial intelligence. This paper shows the outline of CAE system for nuclear power plant in TOSHIBA. (author)
Sophistication and integration of plant engineering CAD-CAE systems
International Nuclear Information System (INIS)
Yoshinaga, Toshiaki; Hanyu, Masaharu; Ota, Yoshimi; Kobayashi, Yasuhiro.
1995-01-01
In respective departments in charge of basic planning, design, manufacture, inspection and construction of nuclear power plants, by the positive utilization of CAD/CAE system, efficient workings have been advanced. This time, the plant integrated CAE system wich heightens the function of these individual systems, and can make workings efficient and advanced by unifying and integrating them was developed. This system is composed of the newly developed application system and the data base system which enables the unified management of engineering data and high speed data conversion in addition to the CAD system for three-dimensional plant layout planning. On the basis of the rich experience and the proposal of improvement of designers by the application of the CAD system for three-dimensional plant layout planning to actual machines, the automation, speed increase and the visualization of input and output by graphical user interface (GUI) in the processing of respective applications were made feasible. As the advancement of plant CAE system, scenic engineering system, integrated layout CAE system, electric instrumentation design CAE system and construction planning CAE system are described. As for the integration of plant CAE systems, the integrated engineering data base, the combination of plant CAE systems, and the operation management in the dispersed environment of networks are reported. At present, Hitachi Ltd. exerts efforts for the construction of atomic energy product in formation integrated management system as the second stage of integration. (K.I.)
Energy Technology Data Exchange (ETDEWEB)
Kortny Rolston
2011-10-01
The Center for Advanced Energy Studies was created to lead research programs important to the nation, attract students and faculty to the Idaho universities and act as a catalyst for technology-based economic development. CAES is striving to meet those goals by continuing to develop its infrastructure and equipment capabilities, expand its research portfolio and bolster Idaho's energy workforce. This Annual Report details the progress CAES made in FY 2011 toward fulfilling its research, education and economic development missions.
Thermal System Analysis and Optimization of Large-Scale Compressed Air Energy Storage (CAES
Directory of Open Access Journals (Sweden)
Zhongguang Fu
2015-08-01
Full Text Available As an important solution to issues regarding peak load and renewable energy resources on grids, large-scale compressed air energy storage (CAES power generation technology has recently become a popular research topic in the area of large-scale industrial energy storage. At present, the combination of high-expansion ratio turbines with advanced gas turbine technology is an important breakthrough in energy storage technology. In this study, a new gas turbine power generation system is coupled with current CAES technology. Moreover, a thermodynamic cycle system is optimized by calculating for the parameters of a thermodynamic system. Results show that the thermal efficiency of the new system increases by at least 5% over that of the existing system.
Method for automated building of spindle thermal model with use of CAE system
Kamenev, S. V.
2018-03-01
The spindle is one of the most important units of the metal-cutting machine tool. Its performance is critical to minimize the machining error, especially the thermal error. Various methods are applied to improve the thermal behaviour of spindle units. One of the most important methods is mathematical modelling based on the finite element analysis. The most common approach for its realization is the use of CAE systems. This approach, however, is not capable to address the number of important effects that need to be taken into consideration for proper simulation. In the present article, the authors propose the solution to overcome these disadvantages using automated thermal model building for the spindle unit utilizing the CAE system ANSYS.
Integrated CAD/CAE for nuclear power plants
International Nuclear Information System (INIS)
Lecoq, P.; Lachat, J.C.
1987-01-01
The size of the French nuclear power program has led both EDF and Framatome to equip themselves progressively with management software, computer-assisted design (CAD) systems, and computer-assisted engineering (CAE) systems. The nature of the projects and of the respective activities of EDF and Framatome determined the essential specifications of these computerized systems. EDF and Framatome have pooled their CAD/CAE efforts in a joint venture (Groupement d'Interet Economique) called GIAO, set up in 1985 by EDF and Aquitaine Systeme (a subsidiary of Framatome and Elf Aquitaine). GIAO's ambition is to become a pole of French CAD/CAE efforts and to foster progress in integrated computer-assisted engineering, by enlarging the synergy of EDF and Framatome in this field to other enterprises that participate in design and construction of complex industrial plants
An integrated environment for developing object-oriented CAE tools
Energy Technology Data Exchange (ETDEWEB)
Hofmann, P.; Ryba, M.; Baitinger, U.G. [Integrated System Engeneering, Stuttgart (Germany)
1996-12-31
This paper presents how object oriented techniques can applied to improve the development of CAE tools. For the design of modular and reusable software systems we use predefined and well tested building blocks. These building blocks are reusable software components based on object-oriented technology which allows the assembling of software systems. Today CAE tools are typically very complex and computation extensive. Therefore we need a concept, that join the advantages of the object-oriented paradigm with the advantages of parallel and distributed programming. So we present a design environment for the development of concurrent-object oriented CAE tools called CoDO.
Energy Technology Data Exchange (ETDEWEB)
Kobayashi, H. (Polyplastic Co. Ltd., Tokyo (Japan))
1992-01-01
Plastic CAE has suddenly being widened their applicable fields recently. On the other hand, since integated program development has also been made worldwidely, currently it is posssible to execute even for shrinkings and warping and warping analysis based on holding pressure analysis and cooling analysis. Polyplastics Company Inc. has paid attention to the usefullness of CAE technologies for engineering plastics from the early times, and in order to utilized them effectively, they have progressed several examinations on CAE software development, improvement of CAE analysis technologies, confirmation and verification of CAE analysis precision, resin data preparations and measuring methods, etc. In this paper, their applications have been introduced mainly by their verification samples such as output sample of FACE-2, which is their originally developped metal mold temperature adjustment design supporting system, and as for verification samples of warping deformation analysis, experimental result of testing metal mold (box type), and reliabilities on the results of measured precision and quantitative analysis of resin data to be used for analysis. 6 refs., 6 figs., 1 tab.
Incremental cost analysis of advanced concept CAES systems
Energy Technology Data Exchange (ETDEWEB)
Knutsen, C.A.
1979-09-01
The costs of compressed air energy storage (CAES) systems using thermal energy storage (TES) are compared to the costs of CAES systems without TES and simple cycle gas turbine systems. Comparisons are made in terms of the system energy costs levelized over the operating life of the systems. These are in 1985 price levels which is the assumed first year of operation for the systems.
Energy Technology Data Exchange (ETDEWEB)
1982-01-01
The design and operational features of compressed air energy storage systems (CAES) in general and, specifically, of a proposed 220 MW plant being planned by the Soyland Power Cooperative, Inc. in Illinois are described. This technology assessment discusses the need for peaking capacity, CAES requirements for land, fuel, water, and storage caverns, and compares the costs, environmental impacts and licensing requirements of CAES with those of power plants using simple cycle or combined cycle combustion turbines. It is concluded that during the initial two years of CAES operation, the CAES would cost more than a combustion turbine or combined cycle facility, but thereafter the CAES would have a increasing economic advantage; the overall environmental impact of a CAES plant is minimal, and that there should be no great difficulties with CAES licensing. (LCL)
Energy Technology Data Exchange (ETDEWEB)
Caro, R. J.; Lopez Trillo, E.
2016-08-01
The enhancements developed in Spain in the area of Emergency Management, as consequence of the accident at the Fukushima Dai-Ichi NPP in 2011, included the definition of new emergency response centers; Alternative Center for Emergency Management (CAGE) on each NPP and the Emergency Support Center (CAE), shared by all NPPs. This article summarizes the main features and operation activities undertaken since the establishment of the new CAE, centralized, external to the NPPs shared by all Spanish plants and managed by Tecnatom. (Author)
Solid modeling and applications rapid prototyping, CAD and CAE theory
Um, Dugan
2016-01-01
The lessons in this fundamental text equip students with the theory of Computer Assisted Design (CAD), Computer Assisted Engineering (CAE), the essentials of Rapid Prototyping, as well as practical skills needed to apply this understanding in real world design and manufacturing settings. The book includes three main areas: CAD, CAE, and Rapid Prototyping, each enriched with numerous examples and exercises. In the CAD section, Professor Um outlines the basic concept of geometric modeling, Hermite and Bezier Spline curves theory, and 3-dimensional surface theories as well as rendering theory. The CAE section explores mesh generation theory, matrix notion for FEM, the stiffness method, and truss Equations. And in Rapid Prototyping, the author illustrates stereo lithographic theory and introduces popular modern RP technologies. Solid Modeling and Applications: Rapid Prototyping, CAD and CAE Theory is ideal for university students in various engineering disciplines as well as design engineers involved in product...
CAE for the development of two-wheeled vehicles. Nirinsha kaihatsu no tame no CAE
Energy Technology Data Exchange (ETDEWEB)
Hirose, T. (Suzuki Motor Co. Ltd., Shizuoka (Japan))
1992-11-01
Applications of CAE to the development of two-wheeled vehicles were outlined. The performance estimation program for 4-cycle engines featured by its easy execution was presented illustrating an estimation model and estimated results, and the FEM generator for strength/rigidity analysis CAE indicating analytical examples of a piston and frame which is featured by easy formation of models and easy execution of advanced analyses by beginners. The vibration analysis system to estimate exciting forces from engine specifications and to estimate vibration levels of bodies with FEM models was also presented together with the estimation system of rider's vibration sensitivity. Furthermore, the noise suppression/ exhaust pressure calculation program to support muffler designs by simultaneous calculation was presented together with the thermal flow analysis program featured by easy calculation with more suitable models illustrating the analytical example of thermal flow in a large luggage box. 7 refs., 15 figs.
A Shift in Emphasis: Comments on CAE's New Mission Statement
Anderson-Levitt, Kathryn M.
2007-01-01
In a presidential address prepared for the 2006 Council on Anthropology and Education (CAE) meeting, I argue that the new mission statement for CAE represents not a new direction for the organization, but simply a shift in emphasis, albeit an important and timely shift.
Stability of the CAE of a digital mammography machine; Estabilidad del CAE de un mamografo digital
Energy Technology Data Exchange (ETDEWEB)
Fernandez Lara, A. A.; Ruiz Morales, C.; Buades Forner, M. J.; Tobarra, B. M.
2013-07-01
We analyzed the long-term reproducibility automatic exposure control (CAE) of a digital mammography machine for possible drifts and the factors that have led to changes in its baseline are discussed. (Author)
Decay Mode Solutions for Kadomtsev-Petviashvili Equation
International Nuclear Information System (INIS)
Fan Guohao; Deng Shufang; Zhang Meng
2012-01-01
The decay mode solutions for the Kadomtsev-Petviashvili (KP) equation are derived by Hirota method (direct method). The decay mode solution is a new set of analytical solutions with Airy function. (general)
Design and operation of the emergency support center, CAE
International Nuclear Information System (INIS)
Caro, R. J.; Lopez Trillo, E.
2016-01-01
The enhancements developed in Spain in the area of Emergency Management, as consequence of the accident at the Fukushima Dai-Ichi NPP in 2011, included the definition of new emergency response centers; Alternative Center for Emergency Management (CAGE) on each NPP and the Emergency Support Center (CAE), shared by all NPPs. This article summarizes the main features and operation activities undertaken since the establishment of the new CAE, centralized, external to the NPPs shared by all Spanish plants and managed by Tecnatom. (Author)
Exergy and Exergoeconomic Model of a Ground-Based CAES Plant for Peak-Load Energy Production
Directory of Open Access Journals (Sweden)
Giampaolo Manfrida
2013-02-01
Full Text Available Compressed Air Energy Storage is recognized as a promising technology for applying energy storage to grids which are more and more challenged by the increasing contribution of renewable such as solar or wind energy. The paper proposes a medium-size ground-based CAES system, based on pressurized vessels and on a multiple-stage arrangement of compression and expansion machinery; the system includes recovery of heat from the intercoolers, and its storage as sensible heat in two separate (hot/cold water reservoirs, and regenerative reheat of the expansions. The CAES plant parameters were adapted to the requirements of existing equipment (compressors, expanders and heat exchangers. A complete exergy analysis of the plant was performed. Most component cost data were procured from the market, asking specific quotations to the industrial providers. It is thus possible to calculate the final cost of the electricity unit (kWh produced under peak-load mode, and to identify the relative contribution between the two relevant groups of capital and component inefficiencies costs.
Expert system for web based collaborative CAE
Hou, Liang; Lin, Zusheng
2006-11-01
An expert system for web based collaborative CAE was developed based on knowledge engineering, relational database and commercial FEA (Finite element analysis) software. The architecture of the system was illustrated. In this system, the experts' experiences, theories and typical examples and other related knowledge, which will be used in the stage of pre-process in FEA, were categorized into analysis process and object knowledge. Then, the integrated knowledge model based on object-oriented method and rule based method was described. The integrated reasoning process based on CBR (case based reasoning) and rule based reasoning was presented. Finally, the analysis process of this expert system in web based CAE application was illustrated, and an analysis example of a machine tool's column was illustrated to prove the validity of the system.
Seneca Compressed Air Energy Storage (CAES) Project
Energy Technology Data Exchange (ETDEWEB)
None
2012-11-30
This document provides specifications for the process air compressor for a compressed air storage project, requests a budgetary quote, and provides supporting information, including compressor data, site specific data, water analysis, and Seneca CAES value drivers.
High spatial sampling global mode structure measurements via multichannel reflectometry in NSTX
Energy Technology Data Exchange (ETDEWEB)
Crocker, N A; Peebles, W A; Kubota, S; Zhang, J [Department of Physics and Astronomy, University of California-Los Angeles, Los Angeles, CA 90095-7099 (United States); Bell, R E; Fredrickson, E D; Gorelenkov, N N; LeBlanc, B P; Menard, J E; Podesta, M [Princeton Plasma Physics Laboratory, PO Box 451, Princeton, NJ 08543-0451 (United States); Sabbagh, S A [Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10027 (United States); Tritz, K [Johns Hopkins University, Baltimore, MD 21218 (United States); Yuh, H [Nova Photonics, Princeton, NJ 08540 (United States)
2011-10-15
Global modes-including kinks and tearing modes (f <{approx} 50 kHz), toroidicity-induced Alfven eigenmodes (TAE; f {approx} 50-250 kHz) and global and compressional Alfven eigenmodes (GAE and CAE; f >{approx} 400 kHz)-play critical roles in many aspects of plasma performance. Their investigation on NSTX is aided by an array of fixed-frequency quadrature reflectometers used to determine their radial density perturbation structure. The array has been recently upgraded to 16 channels spanning 30-75 GHz (n{sub cutoff} = (1.1-6.9) x 10{sup 19} m{sup -3} in O-mode), improving spatial sampling and access to the core of H-mode plasmas. The upgrade has yielded significant new results that advance the understanding of global modes in NSTX. The GAE and CAE structures have been measured for the first time in the core of an NSTX high-power (6 MW) beam-heated H-mode plasma. The CAE structure is strongly core-localized, which has important implications for electron thermal transport. The TAE structure has been measured with greatly improved spatial sampling, and measurements of the TAE phase, the first in NSTX, show strong radial variation near the midplane, indicating radial propagation caused by non-ideal MHD effects. Finally, the tearing mode structure measurements provide unambiguous evidence of coupling to an external kink.
Radionuclide Emission Estimation for the Center for Advanced Energy Studies (CAES)
International Nuclear Information System (INIS)
Schrader, Bradley J.
2010-01-01
An Radiological Safety Analysis Computer Program (RSAC)-7 model dose assessment was performed to evaluate maximum Center for Advanced Energy Studies (CAES) boundary effective dose equivalent (EDE, in mrem/yr) for potential individual releases of radionuclides from the facility. The CAES is a public/private partnership between the State of Idaho and its academic research institutions, the federal government through the U.S. Department of Energy (DOE), and the Idaho National Laboratory (INL) managed by the Battelle Energy Alliance (BEA). CAES serves to advance energy security for our nation by expanding educational opportunities at Idaho universities in energy-related areas, creating new capabilities within its member institutions, and delivering technological innovations leading to technology-based economic development for the intermountain region. CAES has developed a strategic plan (INL/EXT-07-12950) based on the balanced scorecard approach. At the present time it is unknown exactly what processes will be used in the facility in support of this strategic plan. What is known is that the Idaho State University (ISU) Radioactive Materials License (Nuclear Regulatory Commission (NRC) license 11-27380-01) is the basis for handling radioactive material in the facility. The material in this license is shared between the ISU campus and the CAES facility. There currently are no agreements in place to limit the amount of radioactive material at the CAES facility or what is done to the material in the facility. The scope of this analysis is a summary look at the basis dose for each radionuclide included under the license at a distance of 100, 500, and 1,000 m. Inhalation, ingestion and ground surface dose was evaluated using the NRC design basis guidelines. The results can be used to determine a sum of the fractions approach to facility safety. This sum of the fractions allows a facility threshold value (TV) to be established and potential activities to be evaluated against
Seneca Compressed Air Energy Storage (CAES) Project
Energy Technology Data Exchange (ETDEWEB)
None, None
2012-11-30
This report provides a review and an analysis of potential environmental justice areas that could be affected by the New York State Electric & Gas (NYSEG) compress air energy storage (CAES) project and identifies existing environmental burden conditions on the area and evaluates additional burden of any significant adverse environmental impact. The review assesses the socioeconomic and demographic conditions of the area surrounding the proposed CAES facility in Schuyler County, New York. Schuyler County is one of 62 counties in New York. Schuyler County’s 2010 population of 18,343 makes it one of the least populated counties in the State (U.S. Census Bureau, 2010). This report was prepared for WorleyParsons by ERM and describes the study area investigated, methods and criteria used to evaluate this area, and the findings and conclusions from the evaluation.
Application of CAD/CAE/CAM in forging process: a review
International Nuclear Information System (INIS)
Ahmad Baharuddin Abdullah; Hamouda, A.M.S.
2005-01-01
Forging can be described as the process in which metal is plastically deformed with application of huge pressure. The process not only changes the shape but also improves the properties of the forged parts due to grain size refinement. Conventionally, the empirical trial and error method has been applied, but recently there are various tools are employed to improved product quality and economic of the process. For example, Computer Aided Design (CAD) is widely used in modeling of the process, while Computer Aided Engineering (CAE) tools have been utilized in analyzing the process. To physically demonstrate the process, Computer Aided Manufacturing (CAM) such as CNC machine has been exploited. In order to improve forging process efficiency, an integrated system that combines all advantages of CAD, CAM and CAE need to be developed. This paper presents an overview of computer aided simulation such as CAD, CAE and CAM application in forging process. (Author)
Productivity increase through implementation of CAD/CAE workstation
Bromley, L. K.
1985-01-01
The tracking and communication division computer aided design/computer aided engineering system is now operational. The system is utilized in an effort to automate certain tasks that were previously performed manually. These tasks include detailed test configuration diagrams of systems under certification test in the ESTL, floorplan layouts of future planned laboratory reconfigurations, and other graphical documentation of division activities. The significant time savings achieved with this CAD/CAE system are examined: (1) input of drawings and diagrams; (2) editing of initial drawings; (3) accessibility of the data; and (4) added versatility. It is shown that the Applicon CAD/CAE system, with its ease of input and editing, the accessibility of data, and its added versatility, has made more efficient many of the necessary but often time-consuming tasks associated with engineering design and testing.
The application of CAD, CAE & CAM in development of butterfly valve’s disc
Asiff Razif Shah Ranjit, Muhammad; Hanie Abdullah, Nazlin
2017-06-01
The improved design of a butterfly valve disc is based on the concept of sandwich theory. Butterfly valves are mostly used in various industries such as oil and gas plant. The primary failure modes for valves are indented disc, keyways and shaft failure and the cavitation damage. Emphasis on the application of CAD, a new model of the butterfly valve’s disc structure was designed. The structure analysis was analysed using the finite element analysis. Butterfly valve performance factors can be obtained is by using Computational Fluid Dynamics (CFD) software to simulate the physics of fluid flow in a piping system around a butterfly valve. A comparison analysis was done using the finite element to justify the performance of the structure. The second application of CAE is the computational fluid flow analysis. The upstream pressure and the downstream pressure was analysed to calculate the cavitation index and determine the performance throughout each opening position of the valve. The CAM process was done using 3D printer to produce a prototype and analysed the structure in form of prototype. The structure was downscale fabricated based on the model designed initially through the application of CAD. This study is utilized the application of CAD, CAE and CAM for a better improvement of the butterfly valve’s disc components.
Researches on the CAES (Compressed Air Energy Storage) system
Energy Technology Data Exchange (ETDEWEB)
Shin Hee Soon; Kang, Sang Soo; Kwon, Kwang Soo [Korea Institute of Geology Mining and Materials, Taejon (Korea)] [and others
1998-12-01
CAES which is called as a compressed air energy storage was firstly developed at Huntorf, German in 1978. The capacity of that system was 290 MW, and it can be treated as a first commercial power plant. CAES has a lot of merits, such as saving the unit price of power generation, averaging the peak demand, improvement of maintenance, enlarging the benefit of dynamic use. According to the literature survey, the unlined rock cavern should be proposed to be a reasonable storing style as a method of compressed air storage in Korea. In this study, the most important techniques were evaluated through the investigation of the foreign construction case studies, especially on the unlined rock caverns in hard rock mass. We decided the hill of the Korea Institute of Geology, Mining and materials as CAES site. If we construct the underground spaces in this site, the demand for electricity nearby Taejon should be considered. So we could determine the capacity of the power plant as a 350 MW. This capacity needs a underground space of 200,000 m{sup 3}, and we can conclude 4 parallel tunnels through the numerical studies. Design parameters were achieved from 300 m depth boring job and image processing job. Moreover the techniques for determination of joint characteristics from the images could be obtained. Blasting pattern was designed on the underground spaces, and automatic gas control system and thermomechanical characteristics on caverns were also studied. (author). 51 refs., 79 tabs., 114 figs.
Arnold, Steven M.; Bednarcyk, Brett A.; Hussain, Aquila; Katiyar, Vivek
2010-01-01
A unified framework is presented that enables coupled multiscale analysis of composite structures and associated graphical pre- and postprocessing within the Abaqus/CAE environment. The recently developed, free, Finite Element Analysis--Micromechanics Analysis Code (FEAMAC) software couples NASA's Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC) with Abaqus/Standard and Abaqus/Explicit to perform micromechanics based FEA such that the nonlinear composite material response at each integration point is modeled at each increment by MAC/GMC. The Graphical User Interfaces (FEAMAC-Pre and FEAMAC-Post), developed through collaboration between SIMULIA Erie and the NASA Glenn Research Center, enable users to employ a new FEAMAC module within Abaqus/CAE that provides access to the composite microscale. FEA IAC-Pre is used to define and store constituent material properties, set-up and store composite repeating unit cells, and assign composite materials as sections with all data being stored within the CAE database. Likewise FEAMAC-Post enables multiscale field quantity visualization (contour plots, X-Y plots), with point and click access to the microscale i.e., fiber and matrix fields).
Can a wind farm with CAES survive in the day-ahead market?
International Nuclear Information System (INIS)
Mauch, Brandon; Carvalho, Pedro M.S.; Apt, Jay
2012-01-01
We investigate the economic viability of coupling a wind farm with compressed air energy storage (CAES) to participate in the day-ahead electricity market at a time when renewable portfolio standards are not binding and wind competes freely in the marketplace. In our model, the CAES is used to reduce the risk of committing uncertain quantities of wind energy and to shift dispatch of wind generation to high price periods. Other sources of revenue (capacity markets, ancillary services, price arbitrage) are not included in the analysis. We present a model to calculate profit maximizing day-ahead dispatch schedules based on wind forecasts. Annual profits are determined with dispatch schedules and actual wind generation values. We find that annual income for the modeled wind–CAES system would not cover annualized capital costs using market prices from the years 2006 to 2009. We also estimate market prices with a carbon price of $20 and $50 per tonne CO 2 and find that revenue would still not cover the capital costs. The implied cost per tonne of avoided CO 2 to make a wind–CAES profitable from trading on the day-ahead market is roughly $100, with large variability due to electric power prices. - Highlights: ► We modeled a wind farm participating in the day-ahead electricity market. ► We calculated optimal day-ahead market offers based on wind forecasts. ► Revenue is then calculated using measured wind power. ► We find that revenue is insufficient to cover capital costs at current market prices.
Safaei Mohamadabadi, Hossein
Increasing electrification of the economy while decarbonizing the electricity supply is among the most effective strategies for cutting greenhouse gas (GHG) emissions in order to abate climate change. This thesis offers insights into the role of bulk energy storage (BES) systems to cut GHG emissions from the electricity sector. Wind and solar energies can supply large volumes of low-carbon electricity. Nevertheless, large penetration of these resources poses serious reliability concerns to the grid, mainly because of their intermittency. This thesis evaluates the performance of BES systems - especially compressed air energy storage (CAES) technology - for integration of wind energy from engineering and economic aspects. Analytical thermodynamic analysis of Distributed CAES (D-CAES) and Adiabatic CAES (A-CAES) suggest high roundtrip storage efficiencies ( 80% and 70%) compared to conventional CAES ( 50%). Using hydrogen to fuel CAES plants - instead of natural gas - yields a low overall efficiency ( 35%), despite its negligible GHG emissions. The techno-economic study of D-CAES shows that exporting compression heat to low-temperature loads (e.g. space heating) can enhance both the economic and emissions performance of compressed air storage plants. A case study for Alberta, Canada reveals that the abatement cost of replacing a conventional CAES with D-CAES plant practicing electricity arbitrage can be negative (-$40 per tCO2e, when the heat load is 50 km away from the air storage site). A green-field simulation finds that reducing the capital cost of BES - even drastically below current levels - does not substantially impact the cost of low-carbon electricity. At a 70% reduction in the GHG emissions intensity of the grid, gas turbines remain three times more cost-efficient in managing the wind variability compared to BES (in the best case and with a 15-minute resolution). Wind and solar thus, do not need to wait for availability of cheap BES systems to cost
International Nuclear Information System (INIS)
Wang Chuantao
2005-01-01
In the past decade, sheet metal forming and die development has been transformed to a science-based and technology-driven engineering and manufacturing enterprise from a tryout-based craft. Stamping CAE, especially the sheet metal forming simulation, as one of the core components in digital die making and digital stamping, has played a key role in this historical transition. The stamping simulation technology and its industrial applications have greatly impacted automotive sheet metal product design, die developments, die construction and tryout, and production stamping. The stamping CAE community has successfully resolved the traditional formability problems such as splits and wrinkles. The evolution of the stamping CAE technology and business demands opens even greater opportunities and challenges to stamping CAE community in the areas of (1) continuously improving simulation accuracy, drastically reducing simulation time-in-system, and improving operationalability (friendliness) (2) resolving those historically difficult-to-resolve problems such as dimensional quality problems (springback and twist) and surface quality problems (distortion and skid/impact lines) (3) resolving total manufacturability problems in line die operations including blanking, draw/redraw, trim/piercing, and flanging, and (4) overcoming new problems in forming new sheet materials with new forming techniques. In this article, the author first provides an overview of the stamping CAE technology adventures and achievements, and industrial applications in the past decade. Then the author presents a summary of increasing manufacturability needs from the formability to total quality and total manufacturability of sheet metal stampings. Finally, the paper outlines the new needs and trends for continuous improvements and innovations to meet increasing challenges in line die formability and quality requirements in automotive stamping
DEFF Research Database (Denmark)
Salgi, Georges Garabeth; Lund, Henrik
2006-01-01
countries. However, plans to expand wind power locally and in the neighbouring countries could restrain the export option and create transmission congestion challenges. This results in a need to increase the flexibility of the local electricity system. Compressed Air Energy Storage (CAES) has been proposed...... effect on reducing excess electricity production, the storage capacity of CAES has to be increased significantly compared to current technology. It is thus concluded that, seen from a local energy system balance perspective, CAES has little potential for reducing excess electricity production...
Energy Technology Data Exchange (ETDEWEB)
1982-01-01
A method used for siting a compressed air energy storage (CAES) system using geotechnical and environmental criteria is explained using the siting of a proposed 220 MW water-compensated CAES plant in Illinois as an example. Information is included on the identification and comparative ranking of 28 geotechnically and environmental sites in Illinois, the examination of fatal flaws, e.g., mitigation, intensive studies, costly studies, permit denials, at 7 sites; and the selection of 3 sites for further geological surveying. (LCL)
Wang, Chuantao (C. T.)
2005-08-01
In the past decade, sheet metal forming and die development has been transformed to a science-based and technology-driven engineering and manufacturing enterprise from a tryout-based craft. Stamping CAE, especially the sheet metal forming simulation, as one of the core components in digital die making and digital stamping, has played a key role in this historical transition. The stamping simulation technology and its industrial applications have greatly impacted automotive sheet metal product design, die developments, die construction and tryout, and production stamping. The stamping CAE community has successfully resolved the traditional formability problems such as splits and wrinkles. The evolution of the stamping CAE technology and business demands opens even greater opportunities and challenges to stamping CAE community in the areas of (1) continuously improving simulation accuracy, drastically reducing simulation time-in-system, and improving operationalability (friendliness), (2) resolving those historically difficult-to-resolve problems such as dimensional quality problems (springback and twist) and surface quality problems (distortion and skid/impact lines), (3) resolving total manufacturability problems in line die operations including blanking, draw/redraw, trim/piercing, and flanging, and (4) overcoming new problems in forming new sheet materials with new forming techniques. In this article, the author first provides an overview of the stamping CAE technology adventures and achievements, and industrial applications in the past decade. Then the author presents a summary of increasing manufacturability needs from the formability to total quality and total manufacturability of sheet metal stampings. Finally, the paper outlines the new needs and trends for continuous improvements and innovations to meet increasing challenges in line die formability and quality requirements in automotive stamping.
Energy Technology Data Exchange (ETDEWEB)
Hibino, S; Suzuki, K [Central Research Inst. of Electric Power Industry, Tokyo (Japan)
1991-12-01
Compressed air energy storage (CAES) has been studied as a promising storage system which has a good possibility of being put to practical use. Construction of the storage facility is required for CAES. For an economical construction of a storage facility, it is necessary to construct a storage facility by excavating, from the ground surface, a cavity in the ground. There is no case in Japan where rock storage is adopted with several tens of atmospheric pressure which is necessary for CAES. If highly pressurized air can be stored by the water sealing method, it is a very economical method in the case with hard rocks. As the first stem to verify the effectivity of the water sealing system, a water sealing experiment is performed in a boring hole. It is confirmed that water sealing can be possible up to about 40 atmospheres, and it is found that the resistivity, open joint distribution and coefficient of permeability of rocks have correlation as an investigating method for potential cracks in rocks and that resistivity tomography is effective for the investigation of cracks in rocks. 9 ref., 23 figs., 6 tabs.
DEFF Research Database (Denmark)
Lund, Henrik; Salgi, Georges; Elmegaard, Brian
2009-01-01
on electricity spot markets by storing energy when electricity prices are low and producing electricity when prices are high. In order to make a profit on such markets, CAES plant operators have to identify proper strategies to decide when to sell and when to buy electricity. This paper describes three...... plants will not be able to achieve such optimal operation, since the fluctuations of spot market prices in the coming hours and days are not known. Consequently, two simple practical strategies have been identified and compared to the results of the optimal strategy. This comparison shows that...... independent computer-based methodologies which may be used for identifying the optimal operation strategy for a given CAES plant, on a given spot market and in a given year. The optimal strategy is identified as the one which provides the best business-economic net earnings for the plant. In practice, CAES...
Use of phase change materials during compressed air expansion for isothermal CAES plants
Castellani, B.; Presciutti, A.; Morini, E.; Filipponi, M.; Nicolini, A.; Rossi, F.
2017-11-01
Compressed air energy storage (CAES) plants are designed to store compressed air into a vessel or in an underground cavern and to expand it in an expansion turbine when energy demand is high. An innovative CAES configuration recently proposed is the isothermal process. Several methods to implement isothermal CAES configuration are under investigation. In this framework, the present paper deals with the experimental testing of phase change materials (PCM) during compressed air expansion phase. The experimental investigation was carried out by means of an apparatus constituted by a compression section, a steel pressure vessel, to which an expansion valve is connected. The initial internal absolute pressure was equal to 5 bar to avoid moisture condensation and the experimental tests were carried out with two paraffin-based PCM amounts (0.05 kg and 0.1 kg). Results show that the temperature change during air expansion decreases with increasing the PCM amount inside the vessel. With the use of PCM during expansions an increase of the expansion work occurs. The increase is included in the range from 9.3% to 18.2%. In every test there is an approach to the isothermal values, which represent the maximum theoretical value of the obtainable expansion work.
HITACHI construction CAE system
International Nuclear Information System (INIS)
Yoshida, M.
1994-01-01
Construction and maintenance of nuclear power plants have important problems such as shortening the construction period and reducing the construction cost. Recently, the problem of insufficient construction labor has arisen, and as drastic strategic development has become a necessary counter-measure. The following four principles are included in the measures to be taken for efficient execution of the construction work within the short construction period: (1) reduction of on-site work and expansion of module block making, (2)improvement of the accuracy of the on-site work process, adjustment and expansion of the work in parallel with the construction process, (3)improvement of efficiency of the on-site work and mechanization and automation of the work, (4)improvement of the accuracy of the management of the construction. A three dimensional simulation system plant construction plan CAE, comprising five modules has been developed. A project management system was also developed to improve the accuracy and efficiency of management work in the field
International Nuclear Information System (INIS)
Ghalelou, Afshin Najafi; Fakhri, Alireza Pashaei; Nojavan, Sayyad; Majidi, Majid; Hatami, Hojat
2016-01-01
Highlights: • Optimal stochastic energy management of renewable energy sources (RESs) is proposed. • The compressed air energy storage (CAES) besides RESs is used in the presence of DRP. • Determination charge and discharge of CAES in order to reduce the expected operation cost. • Moreover, demand response program (DRP) is proposed to minimize the operation cost. • The uncertainty modeling of input data are considered in the proposed stochastic framework. - Abstract: In this paper, a stochastic self-scheduling of renewable energy sources (RESs) considering compressed air energy storage (CAES) in the presence of a demand response program (DRP) is proposed. RESs include wind turbine (WT) and photovoltaic (PV) system. Other energy sources are thermal units and CAES. The time-of-use (TOU) rate of DRP is considered in this paper. This DRP shifts the percentage of load from the expensive period to the cheap one in order to flatten the load curve and minimize the operation cost, consequently. The proposed objective function includes minimizing the operation costs of thermal unit and CAES, considering technical and physical constraints. The proposed model is formulated as mixed integer linear programming (MILP) and it is been solved using General Algebraic Modeling System (GAMS) optimization package. Furthermore, CAES and DRP are incorporated in the stochastic self-scheduling problem by a decision maker to reduce the expected operation cost. Meanwhile, the uncertainty models of market price, load, wind speed, temperature and irradiance are considered in the formulation. Finally, to assess the effects of DRP and CAES on self-scheduling problem, four case studies are utilized, and significant results were obtained, which indicate the validity of the proposed stochastic program.
DESIGN OF A SUPERBIKE PADDOCK STAND USING CAD AND CAE TOOLS
Directory of Open Access Journals (Sweden)
M.H. Mohd Noh
2012-06-01
Full Text Available Two people are required to operate current superbike paddock stands in order to elevate the superbike. Lifting the superbike alone using the current design of paddock stand may be impractical and inconvenient for users. To overcome this limitation, a new design of a superbike paddock stand was conceived that could be operated by a single user. CAD and CAE tools using CATIA V5R18 software were utilised in designing this new stand. A 3D CAD model was developed and analysed through finite element analysis (FEA and a prototype fabricated for verification testing of the design. The use of CAD and CAE tools saved much time in the design work and gave the researchers and designers freedom in producing their own design. However, the most important aspect of this design study was to design a superbike paddock stand that is more practical and convenient for operation by a single user.
A general solution strategy of modified power method for higher mode solutions
International Nuclear Information System (INIS)
Zhang, Peng; Lee, Hyunsuk; Lee, Deokjung
2016-01-01
A general solution strategy of the modified power iteration method for calculating higher eigenmodes has been developed and applied in continuous energy Monte Carlo simulation. The new approach adopts four features: 1) the eigen decomposition of transfer matrix, 2) weight cancellation for higher modes, 3) population control with higher mode weights, and 4) stabilization technique of statistical fluctuations using multi-cycle accumulations. The numerical tests of neutron transport eigenvalue problems successfully demonstrate that the new strategy can significantly accelerate the fission source convergence with stable convergence behavior while obtaining multiple higher eigenmodes at the same time. The advantages of the new strategy can be summarized as 1) the replacement of the cumbersome solution step of high order polynomial equations required by Booth's original method with the simple matrix eigen decomposition, 2) faster fission source convergence in inactive cycles, 3) more stable behaviors in both inactive and active cycles, and 4) smaller variances in active cycles. Advantages 3 and 4 can be attributed to the lower sensitivity of the new strategy to statistical fluctuations due to the multi-cycle accumulations. The application of the modified power method to continuous energy Monte Carlo simulation and the higher eigenmodes up to 4th order are reported for the first time in this paper. -- Graphical abstract: -- Highlights: •Modified power method is applied to continuous energy Monte Carlo simulation. •Transfer matrix is introduced to generalize the modified power method. •All mode based population control is applied to get the higher eigenmodes. •Statistic fluctuation can be greatly reduced using accumulated tally results. •Fission source convergence is accelerated with higher mode solutions.
Automated knowledge base development from CAD/CAE databases
Wright, R. Glenn; Blanchard, Mary
1988-01-01
Knowledge base development requires a substantial investment in time, money, and resources in order to capture the knowledge and information necessary for anything other than trivial applications. This paper addresses a means to integrate the design and knowledge base development process through automated knowledge base development from CAD/CAE databases and files. Benefits of this approach include the development of a more efficient means of knowledge engineering, resulting in the timely creation of large knowledge based systems that are inherently free of error.
The impact of software and CAE tools on SEU in field programmable gate arrays
International Nuclear Information System (INIS)
Katz, R.; Wang, J.; McCollum, J.; Cronquist, B.
1999-01-01
Field programmable gate array (FPGA) devices, heavily used in spacecraft electronics, have grown substantially in size over the past few years, causing designers to work at a higher conceptual level, with computer aided engineering (CAE) tools synthesizing and optimizing the logic from a description. It is shown that the use of commercial-off-the-shelf (COTS) CAE tools can produce unreliable circuit designs when the device is used in a radiation environment and a flip-flop is upset. At a lower level, software can be used to improve the SEU performance of a flip-flop, exploiting the configurable nature of FPGA technology and on-chip delay, parasitic resistive, and capacitive circuit elements
Use of CAE-Systems at Evaluation of Shock Absorbers for Metallurgical Equipment
Directory of Open Access Journals (Sweden)
Artiukh Viktor
2016-01-01
Full Text Available Work presents results of strength calculations of absorber elastic element that were done by CAE-system and standard method of calculating. It is shown, that use of FEM software allows studying thoroughly the distribution of appropriate stresses on surfaces of elastic element.
Compressed air energy storage (CAES) - possibilities in Denmark
DEFF Research Database (Denmark)
Elmegaard, Brian; Szameitat, Nicklas; Brix, Wiebke
2005-01-01
Through a systematic development of the Danish electrical supply system with wind power and CHP, problems with stability and electricity surplus have appeared. Therefore, the possibilities for profitably implementing a CAES plant for energy storage, peak shaving and electricity surplus reduction...... are investigated. Based on existing plants and the latest technology a simulation model of a 360 MW plant with an efficiency of 35 % has been developed and optimized to Danish conditions. An analysis of the economics in the plant, operating under market conditions, shows a growing potential, but the allocated...
CAE for Injection Molding — Past, Present and the Future
Wang, Kuo K.
2004-06-01
It is well known that injection molding is the most effective process for mass-producing discrete plastic parts of complex shape to the highest precision at the lowest cost. However, due to the complex property of polymeric materials undergoing a transient non-isothermal process, it is equally well recognized that the quality of final products is often difficult to be assured. This is particularly true when a new mold or material is encountered. As a result, injection molding has often been viewed as an art than a science. During the past few decades, numerical simulation of injection molding process based on analytic models has become feasible for practical use as computers became faster and cheaper continually. A research effort was initiated at the Cornell Injection Molding Program (CIMP) in 1974 under a grant from the National Science Foundation. Over a quarter of the century, CIMP has established some scientific bases ranging from materials characterization, flow analysis, to prediction of part quality. Use of such CAE tools has become common place today in industry. Present effort has been primarily aimed at refinements of many aspects of the process. Computational efficiency and user-interface have been main thrusts by commercial software developers. Extension to 3-dimensional flow analysis for certain parts has drawn some attention. Research activities are continuing on molding of fiber-filled materials and reactive polymers. Expanded molding processes such as gas-assisted, co-injection, micro-molding and many others are continually being investigated. In the future, improvements in simulation accuracy and efficiency will continue. This will include in-depth studies on materials characterization. Intelligent on-line process control may draw more attention in order to achieve higher degree of automation. As Internet technology continues to evolve, Web-based CAE tools for design, production, remote process monitoring and control can come to path. The CAE
On spurious resonant modes in the MOT solution of time domain EFIE
Shi, Yifei
2013-07-01
Theoretically, internal resonant modes should not be induced in the marching-on-in-time (MOT) solution of the time domain electric field integral equation since zero initial conditions are enforced at the beginning of time marching and the internal resonant modes do not satisfy these initial conditions. However, these spurious modes are always observed in the MOT solution. It has been conjectured in the past that numerical errors might establish the necessary initial conditions and allow the incident field to induce the internal resonant modes. Systematic numerical experiments carried out in this work prove this conjecture by demonstrating that the internal resonant modes\\' amplitudes are indeed dictated by the numerical errors and the spectrum of the incident field. © 2013 IEEE.
Three-dimensional integrated CAE system applying computer graphic technique
International Nuclear Information System (INIS)
Kato, Toshisada; Tanaka, Kazuo; Akitomo, Norio; Obata, Tokayasu.
1991-01-01
A three-dimensional CAE system for nuclear power plant design is presented. This system utilizes high-speed computer graphic techniques for the plant design review, and an integrated engineering database for handling the large amount of nuclear power plant engineering data in a unified data format. Applying this system makes it possible to construct a nuclear power plant using only computer data from the basic design phase to the manufacturing phase, and it increases the productivity and reliability of the nuclear power plants. (author)
CAE Analysis of Secondary Shaft Systems in Great Five-axis Turning-Milling Complex CNC Machine
Directory of Open Access Journals (Sweden)
Chih-Chiang Hong
2018-01-01
Full Text Available The commercial computer aided engineering (CAE software is used to analyze the linear-static construction, stress and deformation for the secondary shaft systems in great five-axis turning-milling complex computer numerical control (CNC machine. It is convenient and always only three dimensional (3D graphic parts needed firstly prepared and further more detail used for the commercial CAE. It is desirable to predict a deformed position for the cut tool under external pressure loads in the working process of CNC machine. The linear results for static analysis of stresses, displacements in corresponding to the screw shaft locates at top, medium and bottom positions of the secondary shaft systems are obtained by using the simulation module of SOLIDWORKS®.
Directory of Open Access Journals (Sweden)
Flavio Ricci Martinez
2017-12-01
Full Text Available This work aims to understand the contributions of CAD / CAE technology development projects Agricultural Machinery and Implements. The segment of Agricultural Machinery and Implements part of capital goods, which provides items that will be used to produce goods and services in other sectors and that is strategic in many economically and for innovation and technological diffusion in the country sector. To achieve the proposed objective a case study was conducted at a manufacturer of this type of product (combines, planters, tractors, etc. located in the region of Ribeirão Preto. Among the main contributions can excel found to reduce the time and costs of the project, the largest customer interaction, integration with the staff and the increased ability to test alternative solutions for solving problems.
Non-linear modulation of short wavelength compressional Alfven eigenmodes
Energy Technology Data Exchange (ETDEWEB)
Fredrickson, E. D.; Gorelenkov, N. N.; Podesta, M.; Gerhardt, S. P.; Bell, R. E.; Diallo, A.; LeBlanc, B. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Bortolon, A. [University of California, Irvine, California 92697 (United States); Crocker, N. A. [University of California, Los Angeles, California 90095 (United States); Levinton, F. M.; Yuh, H. [Nova Photonics, Princeton, New Jersey 08543 (United States)
2013-04-15
Most Alfvenic activity in the frequency range between toroidal Alfven eigenmodes and roughly one half of the ion cyclotron frequency on National Spherical Torus eXperiment [Ono et al., Nucl. Fusion 40, 557 (2000)], that is, approximately 0.3 MHz up to Almost-Equal-To 1.2 MHz, are modes propagating counter to the neutral beam ions. These have been modeled as Compressional and Global Alfven Eigenmodes (CAE and GAE) and are excited through a Doppler-shifted cyclotron resonance with the beam ions. There is also a class of co-propagating modes at higher frequency than the counter-propagating CAE and GAE. These modes have been identified as CAE, and are seen mostly in the company of a low frequency, n = 1 kink-like mode. In this paper, we present measurements of the spectrum of these high frequency CAE (hfCAE) and their mode structure. We compare those measurements to a simple model of CAE and present a predator-prey type model of the curious non-linear coupling of the hfCAE and the low frequency kink-like mode.
On the DC loop modes in the MOT solution of the time domain EFIE
Shi, Yifei; Bagci, Hakan; Lu, Mingyu
2014-01-01
When marching-on-in-time (MOT) method is applied to solve the time domain electric field integral equation (TD-EFIE), DC loop modes are always observed in the solution. In theory these modes should not be observed since they do not satisfy the relaxed initial conditions. Their appearance is attributed to numerical errors. It is shown here that when Rao-Wilton-Glisson basis and Lagrange interpolation functions are used to discretize the TD-EFIE, errors due to this space-time discretization have zero impact on the DC loop modes. Numerical experiments demonstrate that the numerical errors due to approximate solution of the MOT matrix system have more dominant impact on DC loop modes in the MOT solution.
On the DC loop modes in the MOT solution of the time domain EFIE
Shi, Yifei
2014-07-01
When marching-on-in-time (MOT) method is applied to solve the time domain electric field integral equation (TD-EFIE), DC loop modes are always observed in the solution. In theory these modes should not be observed since they do not satisfy the relaxed initial conditions. Their appearance is attributed to numerical errors. It is shown here that when Rao-Wilton-Glisson basis and Lagrange interpolation functions are used to discretize the TD-EFIE, errors due to this space-time discretization have zero impact on the DC loop modes. Numerical experiments demonstrate that the numerical errors due to approximate solution of the MOT matrix system have more dominant impact on DC loop modes in the MOT solution.
International Nuclear Information System (INIS)
Zhao, Pan; Dai, Yiping; Wang, Jiangfeng
2014-01-01
Electricity generated from renewable wind sources is highly erratic due to the intermittent nature of wind. This uncertainty of wind power can lead to challenges regarding power system operation and dispatch. Energy storage system in conjunction with wind energy system can offset these effects, making the wind power controllable. Moreover, the power spectrum of wind power exhibits that the fluctuations of wind power include various components with different frequencies and amplitudes. Thus, the hybrid energy storage system is more suitable for smoothing out the wind power fluctuations effectively rather than the independent energy storage system. A hybrid energy storage system consisting of adiabatic compressed air energy storage (A-CAES) system and flywheel energy storage system (FESS) is proposed for wind energy application. The design of the proposed system is laid out firstly. The A-CAES system operates in variable cavern pressure, constant turbine inlet pressure mode, whereas the FESS is controlled by constant power strategy. Then, the off-design analysis of the proposed system is carried out. Meanwhile, a parametric analysis is also performed to investigate the effects of several parameters on the system performance, including the ambient conditions, inlet temperature of compressor, storage cavern temperature, maximum and minimum pressures of storage cavern. - Highlights: • A wind-hybrid energy storage system composed of A-CAES and FESS is proposed. • The design of the proposed hybrid energy storage system is laid out. • The off-design analysis of the proposed system is carried out. • A parametric analysis is conducted to examine the system performance
An experimental study of the response of the Galesville sandstone to simulated CAES conditions
Energy Technology Data Exchange (ETDEWEB)
Erikson, R L; Stottlemyre, J A; Smith, R P
1980-07-01
The objective of this experimental study was to determine how the mineralogical and physical characteristics of host rock formations are affected by environmental conditions anticipated for compressed air energy storage (CAES) in porous, permeable rock. In this study, Galesville sandstone cores were reacted in autoclave pressure vessels supporting one of four environments: dry air; heated, air-water vapor; heated, nitrogen-water vapor mixtures; and heated, compressed, liquid water. The simulated CAES environments were maintained in autoclave pressure vessels by controlling the following independent variables: temperature, pressure, time, oxygen content, carbon dioxide content, nitrogen content, and liquid volume. The dependent variables studied were: apparent porosity, gas permeability, water permeability, and friability. These variables were measured at ambient temperature and pressure before and after each sandstone sample was reacted in one of the CAES environments. The experiments gave the following results: the Galesville sandstone exhibited excellent stability in dry air at all temperatures tested (50/sup 0/ to 300/sup 0/C); and significant physical alterations occurred in sandstone samples exposed to liquid water above 150/sup 0/C. Samples shielded from dripping water exhibited excellent stability to 300/sup 0/C; sandstone may be a suitable storage media for heated, humid air provided elevated temperature zones are relatively free of mobile liquid water; and observed changes in the physical properties of the rock may have been caused, in part, by the lack of confining stress on the sample. The inability to apply confining pressure is a severe limitation of autoclave experiments.
Directory of Open Access Journals (Sweden)
Cristina Raluca POPESCU
2015-07-01
Full Text Available In the paper “The Assessment Methodologies PTELR, ADRI and CAE – Three Methodologies for Coordinating the Efforts to Improve the Organizational Processes to Achieve Excellence” the authors present the basic features of the assessment methodologies PTELR, ADRI and CAE that are designed to coordinate the efforts to improve the organizational processes in order to achieve excellence. In the first part of the paper (the introduction of the paper, the authors present the general background concerning the performance of management business processes and the importance of achieving excellence and furthermore correctly assessing/evaluating it. Aspects such as quality, quality control, quality assurance, performance and excellence are brought into discussion in the context generated by globalization, new technologies and new business models. Moreover, aspects regarding the methods employed to ensure the quality, maintaining it and continuous improvements, as well as total quality management, are also main pillars of this current research. In the content of the paper (the assessment methodologies PTELR, ADRI and CAE – as methodologies for coordinating the efforts to improve the organizational processes to achieve excellence, the authors describe the characteristics of the assessment methodologies PTELR, ADRI and CAE from a theoretical point of view.
Matrix method for two-dimensional waveguide mode solution
Sun, Baoguang; Cai, Congzhong; Venkatesh, Balajee Seshasayee
2018-05-01
In this paper, we show that the transfer matrix theory of multilayer optics can be used to solve the modes of any two-dimensional (2D) waveguide for their effective indices and field distributions. A 2D waveguide, even composed of numerous layers, is essentially a multilayer stack and the transmission through the stack can be analysed using the transfer matrix theory. The result is a transfer matrix with four complex value elements, namely A, B, C and D. The effective index of a guided mode satisfies two conditions: (1) evanescent waves exist simultaneously in the first (cladding) layer and last (substrate) layer, and (2) the complex element D vanishes. For a given mode, the field distribution in the waveguide is the result of a 'folded' plane wave. In each layer, there is only propagation and absorption; at each boundary, only reflection and refraction occur, which can be calculated according to the Fresnel equations. As examples, we show that this method can be used to solve modes supported by the multilayer step-index dielectric waveguide, slot waveguide, gradient-index waveguide and various plasmonic waveguides. The results indicate the transfer matrix method is effective for 2D waveguide mode solution in general.
Almacenamiento de energía mediante aire comprimido: Plantas CAES.
Muñoz Diez de la Cortina, Alejandro
2015-01-01
El presente proyecto estudia el estado del arte en cuanto a tecnología CAES se refiere, en un intento de compilación de la información disponible en distintos medios de divulgación científica e ingenieril, y haciendo una presentación de las distintas mejoras y desarrollos posibles de la tecnología así como de un acercamiento a las dos plantas ya existentes que utilizan este medio de almacenamiento de energía. El núcleo del proyecto se encuentra en el estudio de los sistemas ...
Tests of US rock salt for long-term stability of CAES reservoirs
Energy Technology Data Exchange (ETDEWEB)
Gehle, R.M.; Thoms, R.L.
1986-01-01
This is a report on laboratory tests to assess the effects of compressed air energy storage (CAES) on rock salt within the US. The project included a conventional laboratory test phase, with triaxial test machines, and a bench-scale test phase performed in salt mines in southern Louisiana. Limited numerical modeling also was performed to serve as a guide in selecting test layouts and for interpreting test data.
Cristina Raluca POPESCU; Gheorghe N. POPESCU
2015-01-01
In the paper “The Assessment Methodologies PTELR, ADRI and CAE – Three Methodologies for Coordinating the Efforts to Improve the Organizational Processes to Achieve Excellence” the authors present the basic features of the assessment methodologies PTELR, ADRI and CAE that are designed to coordinate the efforts to improve the organizational processes in order to achieve excellence. In the first part of the paper (the introduction of the paper), the authors present the general background concer...
Theory and observation of compressional Alfven eigenmodes in low aspect ratio plasma
International Nuclear Information System (INIS)
Gorelenkov, N.N.
2002-01-01
A new theory of radially and poloidally localized Compressional Alfven Eigenmodes (CAE) in low aspect ratio plasma is reported. The theory is applied to identify recently observed instabilities in the MHz frequency range in National Spherical Torus experiments (NSTX). The frequency of observed CAEs is correlated with the characteristic Alfven velocity of the plasma. The observed high frequency modes are explained as CAEs driven by energetic beam ions. The CAE frequency is determined by the Alfven frequency at the mode location on the low field side of the plasma and is given approximately by ω CAE v A m=r, where m is the poloidal mode number, and r is the local minor radius. CAEs are destabilized by free energy in the energetic ion velocity space gradient via Doppler shifted cyclotron resonance with beam ions. Properties of the CAE instability driven by different NBI ion distributions are presented. (author)
Integrated CAE system for nuclear power plants. Development of piping design check system
International Nuclear Information System (INIS)
Narikawa, Noboru; Sato, Teruaki
1994-01-01
Toshiba Corporation has developed and operated the integrated CAE system for nuclear power plants, the core of which is the engineering data base to manage accurately and efficiently enormous amount of data on machinery, equipment and piping. As the first step of putting knowledge base system to practical use, piping design check system has been developed. By automatically checking up piping design, this system aims at the prevention of overlooking mistakes, efficient design works and the overall quality improvement of design. This system is based on the thought that it supports designers, and final decision is made by designers. This system is composed of the integrated data base, a two-dimensional CAD system and three-dimensional CAD system. The piping design check system is one of the application systems of the integrated CAE system. Object-oriented programming is the base of the piping design check system, and design knowledge and CAD data are necessary. As to the method of realizing the check system, the flow of piping design, the checkup functions, the checkup of interference and attribute base, and the integration of the system are explained. (K.I)
Cuestionario de afrontamiento del estrés (CAE) : validación en una muestra mexicana
González Ramírez, Mónica Teresa; Landero Hernández, René
2007-01-01
El artículo describe los resultados de la aplicación del Cuestionario de Afrontamiento del Estrés (San-dín, B. y Chorot, P. (2003). Cuestionario de Afrontamiento del Estrés (CAE): Desarrollo y validación preliminar. Revista de Psicopatología y Psic
CAE applications in a thermoforming mould design
International Nuclear Information System (INIS)
Marjuki, AR; Mohd Ghazali, FA; Ismail, N M; Sulaiman, S; Mohd Khairuddin, I; Majeed, Anwar P P A; Jaafar, AA; Basri, S; Mustapha, F
2016-01-01
Preparation of honeycomb layer is a critical step for successful fabrications of thermoformed based sandwiched structures. This paper deals with an initial investigation on the rapid manufacturing process of corrugated sheet with 120° dihedral angles. Time history of local displacements and thickness, assuming viscous dominated material model for a 1mm thick thermoformable material, was computed by using ANSYS ® Polyflow solver. The quality of formed surfaces was evaluated for selection of mould geometry and assessment of two common variants of thermoforming process. Inadequate mesh refinement of a membrane elements produces satisfactorily detailing and incomplete forming. A perfectly uniform material distribution was predicted using drape forming process. However, the geometrical properties of vacuum formed part are poorly distributed and difficult to control with increasing inflation volumes. Details of the discrepancies and the contributions of the CAE tool to complement traditional trial and error methodology in the process and design development are discussed. (paper)
Antipin, D. Ya; Shorokhov, S. G.; Bondarenko, O. I.
2018-03-01
A possibility of using current software products realizing CAD/CAE-technologies for the assessment of passenger safety in emergency cases on railway transport has been analyzed. On the basis of the developed solid computer model of an anthropometric dummy, the authors carried out an analysis of possible levels of passenger injury during accident collision of a train with an obstacle.
Noise analysis of fluid-valve system in a linear compressor using CAE
International Nuclear Information System (INIS)
Lee, Jun Ho; Jeong, Weui Bong; Kim, Dang Ju
2009-01-01
A linear compressor in a refrigerator uses piston motion to transfer refrigerant so its efficiency is higher than a previous reciprocal compressor. Because of interaction between refrigerant and valves system in the linear compressor, however, noise has been a main issue. In spite of doing many experimental researches, there is no way to rightly predict the noise. In order to solve this limitation, the CAE analysis is applied. For giving credit to these computational data, all of the data are experimentally validated.
Pielesz, Anna; Biniaś, Włodzimierz; Paluch, Jadwiga
2012-01-01
The formation of AGEs progressively increases with normal aging, even in the absence of disease (the pathogenesis of diabetes associated vascular disorders and neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease). However, they are formed at accelerated rates in age-related diseases. The polysaccharides might play a role in wound healing, both internally and externally, and also that they could play a role against inflammation and may lead to the production of better medicines to be used as supplements in cancer treatment. The acid hydrolysis was studied with H2SO4 at 80% concentration to determine the most effective procedure for total hydrolysis of beta-glucan. The standard of beta-glucans acid hydrolysate were compared for commercial oat and oatmeal, mushrooms: Pleurotus ostreatus, Fungus and yeast Saccharomyces cerevisiae. The following materials and reagents were used in the examination: reference beta-(1 --> 3)-(1 --> 6)-glucan, oat and oatmeal, mushrooms: Pleurotus ostreatus, Fungus and yeast Saccharomyces cerevisiae. The Raman spectra of the sample solutions (beta-glucan acid hydrolysates) were recorded on a MAGNA-IR 860 with FT-Raman accessory. Sample was irradiated with a 1064 nm line of the T10-8S Nd spectra-physics model: YAG laser and scattered radiation were collected at 180 degrees, using 4 cm(-1) resolution. The polysaccharide was hydrolyzed into component monosaccharides with 80% H2SO4 at 0 degrees C for 30 minutes and monosaccharide derivatives were subjected to electrophoresis, as in a ealier authors study, on a strip of cellulose acetate membrane (CA-SYS-MINI Cellulose Acetate Systems) in 0.2 M Ca(OAc)2 (pH 7.5) at 10 mA, max. 240 V for 1.5 h. The strips were stained with 0.5% toluidine blue in 3% HOAc solution and then rinsed in distilled water and air-dried. A part of the hexoses (for example glucose) are converted, to products such as 5-hydroxymethylfurfural. Various coloured substances, through the Maillard
Evaluation of hot forming effects mapping for CAE analyses
Knoerr, L.; Faath, T.; Dykeman, J.; Malcolm, S.
2016-08-01
Hot forming has grown significantly in the manufacturing of structural components within the vehicle Body-In-White construction. The superior strength of press hardened steels not only guarantee high resistance to deformation, it also brings a significant weight saving compared to conventional cold formed products. However, the benefit of achieving ultrahigh strength with hot stamping, comes with a reduction in ductility of the press hardened part. This will require advanced material modeling to capture the predicted performances accurately. A technique to optically measure and map the thinning distribution after hot stamping has shown to improve numerical analysis for fracture prediction. The proposed method to determine the forming effects and mapping to CAE models can be integrated into the Vehicle Development Process to shorten the time to production.
Intelligent CAE system of CYCLONE type cyclotron main magnet and its applications
International Nuclear Information System (INIS)
Zhang Tianjue; Chen Yong; Fan Mingwu
1993-01-01
The main magnet that features the cyclotron is the most important part in a cyclotron construction. Though there are many codes devoted to solving magnetic field computation problems, the results depend on the user's skill and experience very much. To help a cyclotron magnet designer get acceptable results, an intelligent CAE system for CYCLONE type cyclotron magnet design and machining has been developed. Reasonable good results could be got even the designer with the help from an expert knowledge library installed in the program
International Nuclear Information System (INIS)
Marczynski, Slawomir
2011-01-01
The integro-differential Berk-Breizman (BB) equation, describing the evolution of particle-driven wave mode is transformed into a simple delayed differential equation form ν∂a(τ)/∂τ=a(τ) -a 2 (τ- 1) a(τ- 2). This transformation is also applied to the two modes extension of the BB theory. The obtained solutions are presented together with the derived asymptotic analytical solutions and the numerical results.
Characteristics study of the gears by the CAD/CAE
Wang, P. Y.; Chang, S. L.; Lee, B. Y.; Nguyen, D. H.; Cao, C. W.
2017-09-01
Gears are the most important transmission component in machines. The rapid development of the machines in industry requires a shorter time of the analysis process. In traditional, the gears are analyzed by setting up the complete mathematical model firstly, considering the profile of cutter and coordinate systems relationship between the machine and the cutter. It is a really complex and time-consuming process. Recently, the CAD/CAE software is well developed and useful in the mechanical design. In this paper, the Autodesk Inventor® software is introduced to model the spherical gears firstly, and then the models can also be transferred into ANSYS Workbench for the finite element analysis. The proposed process in this paper is helpful to the engineers to speed up the analyzing process of gears in the design stage.
Shi, Yifei; Bagci, Hakan; Lu, Mingyu
2014-01-01
When marching-on-in-time (MOT) method is applied to solve the time-domain electric field integral equation, spurious internal resonant and static loop modes are always observed in the solution. The internal resonant modes have recently been studied by the authors; this letter investigates the static loop modes. Like internal resonant modes, static loop modes, in theory, should not be observed in the MOT solution since they do not satisfy the zero initial conditions; their appearance is attributed to numerical errors. It is discussed in this letter that the dependence of spurious static loop modes on numerical errors is substantially different from that of spurious internal resonant modes. More specifically, when Rao-Wilton-Glisson functions and Lagrange interpolation functions are used as spatial and temporal basis functions, respectively, errors due to space-time discretization have no discernible impact on spurious static loop modes. Numerical experiments indeed support this discussion and demonstrate that the numerical errors due to the approximate solution of the MOT matrix system have dominant impact on spurious static loop modes in the MOT solution. © 2014 IEEE.
Energy Efficiency Analysis of Discharge Modes of an Adiabatic Compressed Air Energy Storage System
Shane D. Inder; Mehrdad Khamooshi
2017-01-01
Efficient energy storage is a crucial factor in facilitating the uptake of renewable energy resources. Among the many options available for energy storage systems required to balance imbalanced supply and demand cycles, compressed air energy storage (CAES) is a proven technology in grid-scale applications. This paper reviews the current state of micro scale CAES technology and describes a micro-scale advanced adiabatic CAES (A-CAES) system, where heat generated during compression is stored fo...
International Nuclear Information System (INIS)
Watanabe, T.-H.; Sugama, H.; Sato, T.
1999-12-01
A non-dissipative drift kinetic simulation scheme, which rigorously satisfies the time-reversibility, is applied to the three-mode coupling problem of the ion temperature gradient (ITG) instability. It is found from the simulation that the three-mode ITG system repeats growth and decay with a period which shows a logarithmic divergence for infinitesimal initial perturbations. Accordingly, time average of the mode amplitude vanishes, as the initial amplitude approaches to zero. An exact solution is analytically given for a class of initial conditions. An excellent agreement is confirmed between the analytical solution and numerical results. The results obtained here provide a useful reference for basic benchmarking of theories and simulation of the ITG modes. (author)
Whispering Gallery Mode Based Optical Fiber Sensor for Measuring Concentration of Salt Solution
Directory of Open Access Journals (Sweden)
Chia-Chin Chiang
2013-01-01
Full Text Available An optical fiber solution-concentration sensor based on whispering gallery mode (WGM is proposed in this paper. The WGM solution-concentration sensors were used to measure salt solutions, in which the concentrations ranged from 1% to 25% and the wavelength drifted from the left to the right. The experimental results showed an average sensitivity of approximately 0.372 nm/% and an R2 linearity of 0.8835. The proposed WGM sensors are of low cost, feasible for mass production, and durable for solution-concentration sensing.
Intelligent CAE system of CYCLONE type cyclotron main magnet and its applications
International Nuclear Information System (INIS)
Zhang Tianjue; Chen Yong; Fan Mingwu
1992-07-01
The main magnet that represents the feature of the cyclotron is the most important part in a cyclotron construction. Though there are many codes devoted to solve magnetic field computation problems, the results from them depend on the user's skill and experience very much. To help cyclotron magnet designer to get acceptable results, an intelligent CAE (computer aided engineering) system for CYCLONE type cyclotron magnet design and machining has been developed. A reasonable good results in the design could be got even if the designer is a beginner, because of the help from an expert knowledge library installed in the program
On spurious resonant modes in the MOT solution of time domain EFIE
Shi, Yifei; Bagci, Hakan; Lu, Mingyu
2013-01-01
Theoretically, internal resonant modes should not be induced in the marching-on-in-time (MOT) solution of the time domain electric field integral equation since zero initial conditions are enforced at the beginning of time marching and the internal
Dual-mode ultraflow access networks: a hybrid solution for the access bottleneck
Kazovsky, Leonid G.; Shen, Thomas Shunrong; Dhaini, Ahmad R.; Yin, Shuang; De Leenheer, Marc; Detwiler, Benjamin A.
2013-12-01
Optical Flow Switching (OFS) is a promising solution for large Internet data transfers. In this paper, we introduce UltraFlow Access, a novel optical access network architecture that offers dual-mode service to its end-users: IP and OFS. With UltraFlow Access, we design and implement a new dual-mode control plane and a new dual-mode network stack to ensure efficient connection setup and reliable and optimal data transmission. We study the impact of the UltraFlow system's design on the network throughput. Our experimental results show that with an optimized system design, near optimal (around 10 Gb/s) OFS data throughput can be attained when the line rate is 10Gb/s.
Development and application of intelligent CAE system for cyclotron main magnet
International Nuclear Information System (INIS)
Zhang Tianjue; Chen Yong; Fan Mingwu
1993-01-01
The main magnet that represents the feature of the cyclotron is the most important part in a cyclotron construction. Though there are many codes devoted to solve magnetic field computation problems, the results from them are depended on user's skill and experience very much. To help cyclotron magnet designer get acceptable result an intelligent CAE system for cyclotron main magnet design and machining has been developed. A reasonable good results in design could be get even the designer is a beginner with the help from an expert knowledge library installed in the program. The codes include following functions: 1. Intelligent CAD; 2. 2D and 3D magnetic field computation; 3. Beam dynamics analysis; 4. CAM for main magnet
International Nuclear Information System (INIS)
Wang Shunbao; Guo Lei; Niu Wenzhe
1997-01-01
Ten clones were picked from cultured colonies of CaEs-17 cell line and developed to a subcell line. The values of SF 2 were measured for each subcell line. Two radioresistant subcell lines, clone 7 and clone 10 were established. According to survival curve assay, for wild type, the value of D 0 was 1.57 Gy, D Q was 1.07 Gy, N was 1.96, SF 2 was 0.41. For clone 7, the value of D 0 was 1.64 Gy, D Q was 1.85 Gy, N was 3.07, SF 2 was 0.53. For clone 10, the value of D 0 was 1.58 Gy, D Q was 2.04 Gy, N was 3.63, SF 2 was 0.61. Clone 7 and clone 10 have much higher values of D Q and N than those of wild type. There was amplification of H-ras gene in clone 10 after 2 Gy irradiation. The amplification of H-ras gene in clone 10 after 2 Gy irradiation might be involved in hetero geneity of CaEs-17 cell line
Chen, W. L.; Chao, F. L.
2018-04-01
Sustainable products become increasingly important for company in addressing eco-performance to satisfy global environmental regulations. Case study of flame guiding module reviewed design process and concerns related to the torch design. For enhancing flame height, the torch was embedded with an airflow guidance structure. The design process and design methodologies were investigated as an eco-design case study. Combine qualitative and CAE simulation were proposed to fulfil its main and auxiliary functions including reduction of impact during use. The design guidelines help prevent mistake arrangements, CAE helps understand combustion phenomenon. The flow field simulation enables fine tune of geometric design. Functional test and measurement are carried out to confirm the product features. On Eco-performance, we choose 5 items for evaluation the status of previous and redesign module, namely function need, low impact material, few manufacturing steps, low energy consumption, and safety. The radar diagram indicates that eco-performance of redesign module is better. Life cycle assessment calculated the carbon footprint of the manufacturing and processing stage with Eco-it. By using recycled steel in the flame module, it reduces raw material stage carbon footprint significantly.
Energy Technology Data Exchange (ETDEWEB)
Gimenez Gonzalez, S.; Sanchez Lombardia, A.; Martin Calvarro, J. M.; Calvin Cuartero, M.
2016-08-01
After Fukushima accident European NPP safety was checked by means of homogenous stress test promoted by European council. At Spain CSN issued Technical instructions to confirm safety NPP margins were appropriate . As a result of this assessment licensees promoted improving NPP safety by strengthen ERO; a new Support Emergency center (CAE) and construction of a new alternative management centre (CAGE) at each site. European countries have been improving and reinforced NPP safety in a similar way to Spain. (Author)
Sizing of Compression Coil Springs Gas Regulators Using Modern Methods CAD and CAE
Directory of Open Access Journals (Sweden)
Adelin Ionel Tuţă
2010-10-01
Full Text Available This paper presents a method for compression coil springs sizing by gas regulators composition, using CAD techniques (Computer Aided Design and CAE (Computer Aided Engineering. Sizing is to optimize the functioning of the regulators under dynamic industrial and house-hold. Gas regulator is a device that automatically and continuously adjusted to maintain pre-set limits on output gas pressure at varying flow and input pressure. The performances of the pressure regulators like automatic systems depend on their behaviour under dynamic opera-tion. Time constant optimization of pneumatic actuators, which drives gas regulators, leads to a better functioning under their dynamic.
International Nuclear Information System (INIS)
Zhou, Rui; Dong, Xueyan; Song, Lanlan; Jing, Hao
2014-01-01
Investigation of interaction mode of bovine serum albumin (BSA) and anthocyanin (ACN) in different solutions will help us understand the interaction mechanism and functional change of bioactive small molecule and biomacromolecule. This study investigated the binding mode, including binding constant, number of binding sites, binding force of BSA and ACN interaction in three buffer solutions of phosphate (PBS), sodium chloride (NaCl), and PBS-NaCl, using fluorescence spectroscopy and synchronous fluorescence spectroscopy. Formation and characteristics of BSA–ACN complex were also investigated using dynamic light scattering (DLS) and transmission electron microscopy (TEM). The results showed that ACN could interact with BSA at both tyrosine (Tyr) and tryptophan (Trp) residues through both hydrogen bonds and van der Waals force, and the same binding mode was seen in dH 2 O and three buffer solutions. The value of binding constant K was decreased as the temperature increased from 298 K to 308 K, and the decreasing degree was in the order of dH 2 O (9.0×10 4 )>NaCl (2.64×10 4 )/PBS (2.37×10 4 )>PBS-NaCl (0.88×10 4 ), which was inversely correlated with the ionic strength of the buffer solutions of PBS-NaCl>NaCl>PBS. It indicated that stability of BSA–ACN complex was affected most in dH 2 O than in three buffer solutions. The BSA and ACN interaction led to formation of BSA–ACN nanoparticles. The sizes of BSA–ACN nanoparticles in dH 2 O were smaller than that in three buffer solutions, which correlated with stronger binding force between BSA and ACN in dH 2 O than in three buffer solutions at room temperature (25 °C, 298 K). - Highlights: • We report the influences of four solutions on the BSA–ACN interaction. • We report the relationship between BSA–ACN interaction and particle size of complex. • The stability of BSA–ACN complex was affected most in dH 2 O than in buffer solutions
Two Novel Methods and Multi-Mode Periodic Solutions for the Fermi-Pasta-Ulam Model
Arioli, Gianni; Koch, Hans; Terracini, Susanna
2005-04-01
We introduce two novel methods for studying periodic solutions of the FPU β-model, both numerically and rigorously. One is a variational approach, based on the dual formulation of the problem, and the other involves computer-assisted proofs. These methods are used e.g. to construct a new type of solutions, whose energy is spread among several modes, associated with closely spaced resonances.
International Nuclear Information System (INIS)
Fredrickson, E.D.; Gorelenkov, E.D.; Cheng, C.Z.; Bell, R.; Darrow, D.; Johnson, D.; Kaye, S.; LeBlanc, B.; Menard, J.; Kubota, S.; Peebles, W.
2001-01-01
With the first injection of neutral beams on the National Spherical Torus Experiment (NSTX), a broad and complicated spectrum of coherent modes was seen between approximately 0.4 MHz and 2.5 MHz [where f(subscript ''ci'')] for deuterium is approximately 2.2 MHz. The modes have been observed with high bandwidth magnetic pick-up coils and with a reflectometer. The parametric scaling of the mode frequency with density and magnetic field is consistent with Alfvenic modes (linear in B, inversely with the square root of density). These modes have been identified as magnetosonic waves or compressional Alfven eigenmodes (CAE) excited by a cyclotron resonance with the neutral-beam ions. Modes have also been observed in the frequency range 50-150 kHz with toroidal mode numbers n = 1-5. These lower frequency modes are thought to be related to the TAE [Toroidal Alfven Eigenmode] seen commonly in tokamaks and driven by energetic fast ion populations resulting from ICRF [ion cyclotron range of frequency] and NBI [neutral-beam injection] heating. There is no clear indication of enhanced fast ion losses associated with the modes
Finite elements as an integrated part of Computer-Aided-Engineering (CAE)
International Nuclear Information System (INIS)
Groth, P.; Kammerer, R.
1986-01-01
The prerequisites for software will be demonstrated using a standard interface for embedding FEM in a CAE system. The realization of a powerful system concept with workstations and personal computers tied to host computers will be presented together with colour graphic terminals for result display. As a standard interface the usage of IGES for the transfer of geometrical data from the CAD system to the FEM preprocessor will be discussed along with the possibilities of usage for new designs and variations for 2D and 3D tasks. In the sectors of pre- and postprocessors a proposal for standardizing the interfaces Pre/FEM, FEM/Post as well as FEM/FEM will be presented (working title FEDIS). The entire problematics will be illustrated by practical examples from mechanical industry and plant design. (orig.)
Directory of Open Access Journals (Sweden)
Duško Lukač
2010-12-01
Full Text Available The paper presents examples of the application of the currently most used CAE software for electrical engineering and project planning EPLAN Electric P8 as well as novel international certification model, of the so called Eplan Certified Engineer (ECE and EPLAN Certified Student, based on cooperation between Rheinische Fachhochschule Köln gGmbH – University of Applied Sciences in cooperation with EPLANSoftware and Service company, a market leader in development and training in electro CAE. It argues that the successful interface management, communication plan and the costumer oriented technical-didactical model of the concept has been essential for the viability and success of the courses. It concludes that cooperation between the industry and university enhances the university’s and firm’s reputation with consumers and environmental competitors and has had positive financial effects for the both parties. It concludes that on the whole, these joint certification programs have a convenient side effect, like to be the successful way for the development of high-quality training opportunities for the students.
Structural failure modes in vertical tanks: reinforcement evaluation and solutions
International Nuclear Information System (INIS)
Alcantud Abellan, M.; Orden Martinez, A.
1995-01-01
Vertical storage tanks are essential components in the safety of nuclear plant systems. It has been shown that the traditional method of analysing seismic loads is not conservative, as it does not take account of the interaction between fluid and tank structure. This paper identifies different possible structural failure modes in tanks due to seismic load, and methods devised by various authors to evaluate tank structure capacity under different failure modes. These methods are based on experimental data relating to the structural behaviour of tanks during actual seismic events, tests, and theoretical analyses. The paper describes the problems of these structures under seismic loads in nuclear plants. It proposes solutions to the main structural problem, tank anchorage, for which the re-evaluation of the anchorage capacity is required, using methods (finite element) less conservative than those proposed by other authors. Also proposed is the local reinforcement of anchorages to increase their capacity. (Author) 4 refs
Goloshumova, V. N.; Kortenko, V. V.; Pokhoriler, V. L.; Kultyshev, A. Yu.; Ivanovskii, A. A.
2008-08-01
We describe the experience ZAO Ural Turbine Works specialists gained from mastering the series of CAD/CAE/CAM/PDM technologies, which are modern software tools of computer-aided engineering. We also present the results obtained from mathematical simulation of the process through which high-and intermediate-pressure rotors are heated for revealing the most thermally stressed zones, as well as the results from mathematical simulation of a new design of turbine cylinder shells for improving the maneuverability of these turbines.
ANSYS UIDL-Based CAE Development of Axial Support System for Optical Mirror
Yang, De-Hua; Shao, Liang
2008-09-01
The Whiffle-tree type axial support mechanism is widely adopted by most relatively large optical mirrors. Based on the secondary developing tools offered by the commonly used Finite Element Anylysis (FEA) software ANSYS, ANSYS Parametric Design Language (APDL) is used for creating the mirror FEA model driven by parameters, and ANSYS User Interface Design Language (UIDL) for generating custom menu of interactive manner, whereby, the relatively independent dedicated Computer Aided Engineering (CAE) module is embedded in ANSYS for calculation and optimization of axial Whiffle-tree support of optical mirrors. An example is also described to illustrate the intuitive and effective usage of the dedicated module by boosting work efficiency and releasing related engineering knowledge of user. The philosophy of secondary-developed special module with commonly used software also suggests itself for product development in other industries.
Directory of Open Access Journals (Sweden)
Yu-Shan Chen
2015-04-01
Full Text Available We reported that the photonic crystal fiber (PCF filled with TI:Bi2Te3 nanosheets solution could act as an effective saturable absorber (SA. Employing this TI-PCF SA device; we constructed an ytterbium-doped all-fiber laser oscillator and achieved the evanescent wave mode-locking operation. Due to the large cavity dispersion; the fundamental mode-locking pulse had the large full width at half maximum (FWHM of 2.33 ns with the repetition rate of ~1.11 MHz; and the radio frequency (RF spectrum with signal-to-noise ratio (SNR of 61 dB. In addition; the transition dynamics from a bunched state of pulses to harmonic mode-locking (HML was also observed; which was up to 26th order.
Directory of Open Access Journals (Sweden)
Matthias Saba
2015-01-01
Full Text Available We propose a new approach to calculate the complex photonic band structure, both purely dispersive and evanescent Bloch modes of a finite range, of arbitrary three-dimensional photonic crystals. Our method, based on a well-established plane wave expansion and the weak form solution of Maxwell’s equations, computes the Fourier components of periodic structures composed of distinct homogeneous material domains from a triangulated mesh representation of the inter-material interfaces; this allows substantially more accurate representations of the geometry of complex photonic crystals than the conventional representation by a cubic voxel grid. Our method works for general two-phase composite materials, consisting of bi-anisotropic materials with tensor-valued dielectric and magnetic permittivities ε and μ and coupling matrices ς. We demonstrate for the Bragg mirror and a simple cubic crystal closely related to the Kelvin foam that relatively small numbers of Fourier components are sufficient to yield good convergence of the eigenvalues, making this method viable, despite its computational complexity. As an application, we use the single gyroid crystal to demonstrate that the consideration of both conventional and evanescent Bloch modes is necessary to predict the key features of the reflectance spectrum by analysis of the band structure, in particular for light incident along the cubic [111] direction.
International Nuclear Information System (INIS)
Ohtsu, Iwao; Murata, Hideo; Kukita, Yutaka; Kumamaru, Hiroshige.
1996-07-01
JAERI, the University of Tokyo, the Central Research Institute of Electric Power Industry and Shimizu Corporation jointing performed and experimental study on two-phase flow in the hydraulically-compensated Compressed Air Energy Storage (CAES) system with a large-diameter vertical pipe two-phase flow test facility from 1993 to 1995. A hydraulically-compensated CAES system is a proposed, conceptual energy storage system where energy is stored in the form of compressed air in an underground cavern which is sealed by a deep (several hundred meters) water shaft. The shaft water head maintains a constant pressure in the cavern, of several mega Pascals, even during loading or unloading of the cavern with air. The dissolved air in the water, however, may create voids in the shaft when the water rises through the shaft during the loading, being forced by the air flow into the cavern. The voids may reduce the effective head of the shaft, and thus the seal may fail, if significant bubbling should occur in the shaft. This bubbling phenomenon (termed 'Champaign effect') and potential failure of the water seal ('blowout') are simulated in a scaled-height, scaled-diameter facility. Carbon dioxide is used to simulate high solubility of air in the full-height, full-pressure system. This report describes the expected and potential two-phase flow phenomena in a hydraulically-compensated CAES system, the test facility and the test procedure, a method to estimate quantities which are not directly measured by using measured quantities and hydrodynamic basic equations, and desirable additional instrumentation. (author)
Solution of the Lambda modes problem of a nuclear power reactor using an h–p finite element method
International Nuclear Information System (INIS)
Vidal-Ferrandiz, A.; Fayez, R.; Ginestar, D.; Verdú, G.
2014-01-01
Highlights: • An hp finite element method is proposed for the Lambda modes problem of a nuclear reactor. • Different strategies can be implemented for increasing the accuracy of the solutions. • 2D and 3D benchmarks have been studied obtaining accurate results. - Abstract: Lambda modes of a nuclear power reactor have interest in reactor physics since they have been used to develop modal methods and to study BWR reactor instabilities. An h–p-Adaptation finite element method has been implemented to compute the dominant modes the fundamental mode and the next subcritical modes of a nuclear reactor. The performance of this method has been studied in three benchmark problems, a homogeneous 2D reactor, the 2D BIBLIS reactor and the 3D IAEA reactor
The enhancement and suppression of immersion mode heterogeneous ice-nucleation by solutes.
Whale, Thomas F; Holden, Mark A; Wilson, Theodore W; O'Sullivan, Daniel; Murray, Benjamin J
2018-05-07
Heterogeneous nucleation of ice from aqueous solutions is an important yet poorly understood process in multiple fields, not least the atmospheric sciences where it impacts the formation and properties of clouds. In the atmosphere ice-nucleating particles are usually, if not always, mixed with soluble material. However, the impact of this soluble material on ice nucleation is poorly understood. In the atmospheric community the current paradigm for freezing under mixed phase cloud conditions is that dilute solutions will not influence heterogeneous freezing. By testing combinations of nucleators and solute molecules we have demonstrated that 0.015 M solutions (predicted melting point depression nucleate ice up to around 3 °C warmer than they do in pure water. In contrast, dilute solutions of certain alkali metal halides can dramatically depress freezing points for the same nucleators. At 0.015 M, solutes can enhance or deactivate the ice-nucleating ability of a microcline feldspar across a range of more than 10 °C, which corresponds to a change in active site density of more than a factor of 10 5 . This concentration was chosen for a survey across multiple solutes-nucleant combinations since it had a minimal colligative impact on freezing and is relevant for activating cloud droplets. Other nucleators, for instance a silica gel, are unaffected by these 'solute effects', to within experimental uncertainty. This split in response to the presence of solutes indicates that different mechanisms of ice nucleation occur on the different nucleators or that surface modification of relevance to ice nucleation proceeds in different ways for different nucleators. These solute effects on immersion mode ice nucleation may be of importance in the atmosphere as sea salt and ammonium sulphate are common cloud condensation nuclei (CCN) for cloud droplets and are internally mixed with ice-nucleating particles in mixed-phase clouds. In addition, we propose a pathway dependence where
Zhang, Yujie; Terai, Asuka; Nakagawa, Masanori
2013-01-01
Inductive reasoning under risk conditions is an important thinking process not only for sciences but also in our daily life. From this viewpoint, it is very useful for language learning to construct computational models of inductive reasoning which realize the CAE for foreign languages. This study proposes the comparison of inductive reasoning…
Sajjadi, Mohammadreza; Pishkenari, Hossein Nejat; Vossoughi, Gholamreza
2018-06-01
Trolling mode atomic force microscopy (TR-AFM) has resolved many imaging problems by a considerable reduction of the liquid-resonator interaction forces in liquid environments. The present study develops a nonlinear model of the meniscus force exerted to the nanoneedle of TR-AFM and presents an analytical solution to the distributed-parameter model of TR-AFM resonator utilizing multiple time scales (MTS) method. Based on the developed analytical solution, the frequency-response curves of the resonator operation in air and liquid (for different penetration length of the nanoneedle) are obtained. The closed-form analytical solution and the frequency-response curves are validated by the comparison with both the finite element solution of the main partial differential equations and the experimental observations. The effect of excitation angle of the resonator on horizontal oscillation of the probe tip and the effect of different parameters on the frequency-response of the system are investigated.
International Nuclear Information System (INIS)
Gofuku, Akio; Yoshikawa, Hidekazu
1993-01-01
In order to shorten the time span of design work and enhance both consistency and rationality of design products, the authors are now investigating an intelligent CAD/CAE system to support cooperative works by many specialists by adopting object-oriented approach. In this paper, the cognitive aspect of design activities of specialists in the conceptual design phase of nuclear reactors is discussed. The activities of the specialists in their design analysis process are highly knowledge-based and goal-oriented. The characteristics of the activities are 1) hierarchization of design goal into sub-goals, 2) prioritization of design sub-goals and step-by-step practise of design analysis, and 3) abstraction of real-world space structure into more simplified space structure to cope with theoretical treatment. Based on these consideration, a conceptual design model of specialists' activities composed of attribute modeling and design expertise knowledge base is proposed. The 'principle of functional independence' proposed by Sue is applied to bridge between the attribute modeling and design expertise knowledge base. The intelligent CAD/CAE system is now under development by focusing on the conceptual design of a space power reactor core utilizing thermo-ionic fuel elements as direct thermo-to-electric conversion. A program to calculate thermo-hydraulics of reactor core and thermo-ionic power generation has been developed. An interface has been also developed in order to communicate with the specialists at JAERI by E-mail concerning the interactive calculation between our calculation and the neutronics calculation of reactor core. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Gofuku, Akio (Inst. of Atomic Energy, Kyoto Univ. (Japan)); Yoshikawa, Hidekazu (Inst. of Atomic Energy, Kyoto Univ. (Japan))
1993-04-01
In order to shorten the time span of design work and enhance both consistency and rationality of design products, the authors are now investigating an intelligent CAD/CAE system to support cooperative works by many specialists by adopting object-oriented approach. In this paper, the cognitive aspect of design activities of specialists in the conceptual design phase of nuclear reactors is discussed. The activities of the specialists in their design analysis process are highly knowledge-based and goal-oriented. The characteristics of the activities are 1) hierarchization of design goal into sub-goals, 2) prioritization of design sub-goals and step-by-step practise of design analysis, and 3) abstraction of real-world space structure into more simplified space structure to cope with theoretical treatment. Based on these consideration, a conceptual design model of specialists' activities composed of attribute modeling and design expertise knowledge base is proposed. The 'principle of functional independence' proposed by Sue is applied to bridge between the attribute modeling and design expertise knowledge base. The intelligent CAD/CAE system is now under development by focusing on the conceptual design of a space power reactor core utilizing thermo-ionic fuel elements as direct thermo-to-electric conversion. A program to calculate thermo-hydraulics of reactor core and thermo-ionic power generation has been developed. An interface has been also developed in order to communicate with the specialists at JAERI by E-mail concerning the interactive calculation between our calculation and the neutronics calculation of reactor core. (orig.)
Shi, Yifei; Bagci, Hakan; Lu, Mingyu
2013-01-01
Internal resonant modes are always observed in the marching-on-in-time (MOT) solution of the time domain electric field integral equation (EFIE), although 'relaxed initial conditions,' which are enforced at the beginning of time marching, should in theory prevent these spurious modes from appearing. It has been conjectured that, numerical errors built up during time marching establish the necessary initial conditions and induce the internal resonant modes. However, this conjecture has never been proved by systematic numerical experiments. Our numerical results in this communication demonstrate that, the internal resonant modes' amplitudes are indeed dictated by the numerical errors. Additionally, it is shown that in a few cases, the internal resonant modes can be made 'invisible' by significantly suppressing the numerical errors. These tests prove the conjecture that the internal resonant modes are induced by numerical errors when the time domain EFIE is solved by the MOT method. © 2013 IEEE.
Shi, Yifei
2013-08-01
Internal resonant modes are always observed in the marching-on-in-time (MOT) solution of the time domain electric field integral equation (EFIE), although \\'relaxed initial conditions,\\' which are enforced at the beginning of time marching, should in theory prevent these spurious modes from appearing. It has been conjectured that, numerical errors built up during time marching establish the necessary initial conditions and induce the internal resonant modes. However, this conjecture has never been proved by systematic numerical experiments. Our numerical results in this communication demonstrate that, the internal resonant modes\\' amplitudes are indeed dictated by the numerical errors. Additionally, it is shown that in a few cases, the internal resonant modes can be made \\'invisible\\' by significantly suppressing the numerical errors. These tests prove the conjecture that the internal resonant modes are induced by numerical errors when the time domain EFIE is solved by the MOT method. © 2013 IEEE.
Energy Technology Data Exchange (ETDEWEB)
Emmanuel, Bresson; Olivier, Chevassut; David, Pointcheval
2005-10-01
The IEEE 802 standards ease the deployment of networkinginfrastructures and enable employers to accesscorporate networks whiletraveling. These standards provide two modes of communication calledinfrastructure and ad-hoc modes. A security solution for the IEEE802.11's infrastructure mode took several years to reach maturity andfirmware are still been upgraded, yet a solution for the ad-hoc modeneeds to be specified. The present paper is a first attempt in thisdirection. It leverages the latest developments in the area ofpassword-based authentication and (group) Diffie-Hellman key exchange todevelop a provably-secure key-exchange protocol for IEEE 802.11's ad-hocmode. The protocol allows users to securely join and leave the wirelessgroup at time, accommodates either a single-shared password orpairwise-shared passwords among the group members, or at least with acentral server; achieves security against dictionary attacks in theideal-hash model (i.e. random-oracles). This is, to the best of ourknowledge, the first such protocol to appear in the cryptographicliterature.
International Nuclear Information System (INIS)
Kim, Hyung-Mok; Rutqvist, Jonny; Ryu, Dong-Woo; Choi, Byung-Hee; Sunwoo, Choon; Song, Won-Kyong
2012-01-01
Highlights: ► We carried out coupled thermodynamic, multiphase fluid flow and heat transport analysis. ► Coupled behavior associated with underground lined caverns for CAES was investigated. ► Air leakage could be reduced by controlling the permeability of concrete lining. ► Heat loss during compression would be gained back at subsequent decompression phase. -- Abstract: This paper presents a numerical modeling study of coupled thermodynamic, multiphase fluid flow and heat transport associated with underground compressed air energy storage (CAES) in lined rock caverns. Specifically, we explored the concept of using concrete lined caverns at a relatively shallow depth for which constructing and operation costs may be reduced if air tightness and stability can be assured. Our analysis showed that the key parameter to assure long-term air tightness in such a system was the permeability of both the concrete lining and the surrounding rock. The analysis also indicated that a concrete lining with a permeability of less than 1 × 10 −18 m 2 would result in an acceptable air leakage rate of less than 1%, with the operation pressure range between 5 and 8 MPa at a depth of 100 m. It was further noted that capillary retention properties and the initial liquid saturation of the lining were very important. Indeed, air leakage could be effectively prevented when the air-entry pressure of the concrete lining is higher than the operation air pressure and when the lining is kept at relatively high moisture content. Our subsequent energy-balance analysis demonstrated that the energy loss for a daily compression and decompression cycle is governed by the air-pressure loss, as well as heat loss by conduction to the concrete liner and surrounding rock. For a sufficiently tight system, i.e., for a concrete permeability of less than 1 × 10 −18 m 2 , heat loss by heat conduction tends to become proportionally more important. However, the energy loss by heat conduction can be
Studies Regarding Design and Optimization of Mechanisms Using Modern Techniques of CAD and CAE
Directory of Open Access Journals (Sweden)
Marius Tufoi
2010-01-01
Full Text Available The paper presents applications of modern techniques of CAD (Computer Aided Design and CAE (Computer Aided Engineering to design and optimize the mechanisms used in mechanical engineering. The use exemplification of these techniques was achieved by designing and optimizing parts of a drawing installation for horizontal continuous casting of metals. By applying these design methods and using finite element method at simulations on designed mechanisms results a number of advantages over traditional methods of drawing and design: speed in drawing, design and optimization of parts and mechanisms, kinematic analysis option, kinetostatic and dynamic through simulation, without requiring physical realization of the part or mechanism, the determination by finite element method of tension, elongations, travel and safety factor and the possibility of optimization for these sizes to ensure the mechanical strength of each piece separately. Achieving these studies was possible using SolidWorks 2009 software suite.
Acoustic rotation modes in complex plasmas
International Nuclear Information System (INIS)
Bai Dongxue; Wang Zhengxiong; Wang Xiaogang
2004-01-01
Acoustic rotation modes in complex plasmas are investigated in a cylindrical system with an axial symmetry. The linear mode solution is derived. The mode in an infinite area is reduced to a classical dust acoustic wave in the region away from the centre. When the dusty plasma is confined in a finite region, the breathing and rotating-void behaviour are observed. Vivid structures of different mode number solutions are illustrated
Zhang, Linjuan; Qie, Meiying; Su, Jing; Zhang, Shuo; Zhou, Jing; Li, Jiong; Wang, Yu; Yang, Shitong; Wang, Shuao; Li, Jingye; Wu, Guozhong; Wang, Jian Qiang
2018-03-01
The present study sheds some light on the long-standing debate concerning the coordination properties between uranyl ions and the amidoxime ligand, which is a key ingredient for achieving efficient extraction of uranium. Using X-ray absorption fine structure combined with theoretical simulation methods, the binding mode and bonding nature of a uranyl-amidoxime complex in aqueous solution were determined for the first time. The results show that in a highly concentrated amidoxime solution the preferred binding mode between UO 2 2+ and the amidoxime ligand is η 2 coordination with tris-amidoximate species. In such a uranyl-amidoximate complex with η 2 binding motif, strong covalent interaction and orbital hybridization between U 5f/6d and (N, O) 2p should be responsible for the excellent binding ability of the amidoximate ligand to uranyl. The study was performed directly in aqueous solution to avoid the possible binding mode differences caused by crystallization of a single-crystal sample. This work also is an example of the simultaneous study of local structure and electronic structure in solution systems using combined diagnostic tools.
Directory of Open Access Journals (Sweden)
A. Figueredo
2005-03-01
Full Text Available RESUMO: Para verificar a soroprevalÃªncia da artrite-encefalite caprina (Cae foram analisadas 1605 amostras de hemo-soros de caprinos pertencentes a rebanhos localizados em nove microrregiÃµes geogrÃ¡ficas e distribuÃdos em 24 municÃpios do Estado da Bahia, os quais nos foram enviados para exame no LaboratÃ³rio de Viroses da Escola de Medicina VeterinÃ¡ria. A populaÃ§Ã£o estudada compreendeu animais de criatÃ³rios de leite e corte, de manejo intensivo, semi-intensivo e extensivo, das raÃ§as: alpina, anglo-nubiana, boer, mambrina, saanen, toggenburg e sem raÃ§a definida(SRD. Foram positivos ao teste de imunodifusÃ£o em Ã¡gar gel (IDAG 215 (13,4% hemo-soros de caprinos. Nas raÃ§as sanen, alpina e anglo-nubiana foram encontradas um maior nÃºmero de animais positivos, respectivamente 77 (18,92%, 80 (16,06% e 49 (15,76%. Entre as amostras positivas a maior frequÃªncia foi de fÃªmeas 194 (90,23% e adultos 193 (89,77%. Os resultados obtidos comprovam a existÃªncia da CAE na regiÃ£o e a necessidade de novas pesquisas que avaliem o Ãndice de infecÃ§Ã£o dos animais e as formas de prevenÃ§Ã£o e controle da doenÃ§a, PALAVRAS CHAVE: Artrite â encefalite caprina, teste da imunidade, fusÃ£o em agar gel, doenÃ§as em caprinos SUMMARY: To verify the soroprevalency of the caprine arthritis-encephalitis (CAE 1605 samples of goats hemo-serums belonging to flocks located in nine geographical microrregiÃµes were analyzed and distributed in 24 municipal districts of the State of Bahia. This samples were sent to Laboratory of Viruses of the Veterinary Medicine School to analysis. The studied population understood animals of herd of milk and court, of intensive, semi-intensive and extensive handling, of the races: alpine, anglo-nubiana, boer, mambrina, saanen, toggenburg and without race defined(SRD. They were positive to the agar gel imunodifusion test (IDAG 215 (13,4% goats hemo-serums. In the races
Thermal reservoir sizing for adiabatic compressed air energy storage
Energy Technology Data Exchange (ETDEWEB)
Kere, Amelie; Goetz, Vincent; Py, Xavier; Olives, Regis; Sadiki, Najim [Perpignan Univ. (France). PROMES CNRS UPR 8521; Mercier-Allart, Eric [EDF R et D, Chatou (France)
2012-07-01
Despite the operation of the two existing industrial facilities to McIntosh (Alabama), and for more than thirty years, Huntorf (Germany), electricity storage in the form of compressed air in underground cavern (CAES) has not seen the development that was expected in the 80s. The efficiency of this form of storage was with the first generation CAES, less than 50%. The evolving context technique can significantly alter this situation. The new generation so-called Adiabatic CAES (A-CAES) is to retrieve the heat produced by the compression via thermal storage, thus eliminating the necessity of gas to burn and would allow consideration efficiency overall energy of the order of 70%. To date, there is no existing installation of A-CAES. Many studies describe the principal and the general working mode of storage systems by adiabatic compression of air. So, efficiencies of different configurations of adiabatic compression process were analyzed. The aim of this paper is to simulate and analyze the performances of a thermal storage reservoir integrated in the system and adapted to the working conditions of a CAES.
Compressed air storage with humidification (CASH) coal gasification power plant investigation
International Nuclear Information System (INIS)
Nakhamkin, M.; Patel, M.
1991-08-01
A study was performed to investigate and develop a hybrid coal gasification concept which utilizes an air saturator (AS) with an integrated coal gasification/compressed air energy storage (CGS/CAES) plant. This potentially attractive concept is designated as AS/CGS/CAES. In this concept, the coal gasification system provides fuel for the combustors of the CAES reheat turbomachinery train. Motive air from underground storage is humidified by saturators and thereby provides increased power production without additional air consumption. The heat for generating the hot water utilized in the saturators is extracted from waste heat within the overall plant. Multiple alternatives were considered and parametrically analyzed in the study in order to select the most thermodynamically and economically attractive concepts. The major alternatives were differentiated by the type of gasifier, type of CAES turbomachinery, mode of operation, and utilization of waste heat. The results of the study indicate that the use of the air saturation in AS/CGS/CAES plants might reduce capital costs of coal gasification based power used in intermediate load generation by $300 to $400 per kilowatt. Furthermore, heat rates might also be reduced by almost 1.5 cents per kilowatt hour, a major reduction. The major cause of the reduction in electricity costs is a 50% reduction in the required gasification capacity per net kW. In addition to being a load management tool, AS/CGS/CAES concepts provide a method to operate the CGS and turbomachinery in a continuous mode, improving the operation and potentially the life expectancy of both components. 3 refs., 18 figs., 4 tabs
Nonlinear surface elastic modes in crystals
Gorentsveig, V. I.; Kivshar, Yu. S.; Kosevich, A. M.; Syrkin, E. S.
1990-03-01
The influence of nonlinearity on shear horizontal surface elastic waves in crystals is described on the basis of the effective nonlinear Schrödinger equation. It is shown that the corresponding solutions form a set of surface modes and the simplest mode coincides with the solution proposed by Mozhaev. The higher order modes have internal frequencies caused by the nonlinearity. All these modes decay in the crystal as uoexp(- z/ zo) atz≫ zo- u o-1 ( z is the distance from the crystal surface, uo the wave amplitude at the surface). The creation of the modes from a localized surface excitation has a threshold. The stability of the modes is discussed.
Mode I and mixed mode crack-tip fields in strain gradient plasticity
DEFF Research Database (Denmark)
Goutianos, Stergios
2011-01-01
Strain gradients develop near the crack-tip of Mode I or mixed mode cracks. A finite strain version of the phenomenological strain gradient plasticity theory of Fleck–Hutchinson (2001) is used here to quantify the effect of the material length scales on the crack-tip stress field for a sharp...... stationary crack under Mode I and mixed mode loading. It is found that for material length scales much smaller than the scale of the deformation gradients, the predictions converge to conventional elastic–plastic solutions. For length scales sufficiently large, the predictions converge to elastic solutions....... Thus, the range of length scales over which a strain gradient plasticity model is necessary is identified. The role of each of the three material length scales, incorporated in the multiple length scale theory, in altering the near-tip stress field is systematically studied in order to quantify...
Unstable Mode Solutions to the Klein-Gordon Equation in Kerr-anti-de Sitter Spacetimes
Dold, Dominic
2017-03-01
For any cosmological constant {Λ = -3/ℓ2 r+2 > |a|ℓ}. We obtain an analogous result for Neumann boundary conditions if {5/4 < α < 9/4}. Moreover, in the Dirichlet case, one can prove that, for any Kerr-AdS spacetime violating the Hawking-Reall bound, there exists an open family of masses {α} such that the corresponding Klein-Gordon equation permits exponentially growing mode solutions. Our result adopts methods of Shlapentokh-Rothman developed in (Commun. Math. Phys. 329:859-891, 2014) and provides the first rigorous construction of a superradiant instability for negative cosmological constant.
Small deformations of the Prasad-Sommerfield solution
International Nuclear Information System (INIS)
Adler, S.L.
1979-01-01
I study solutions of the static Euclidean anti-self-dual SU(2) Yang-Mills equations which differ by a small perturbation from the Prasad-Sommerfield solution. I find explicit expressions for two series of perturbation mode functions of angular momentum l and even and odd parity, and classify the modes according to several criteria. There are seven nondilatational modes which have singularities removable by gauge transformation: 3 translations (l = 1), 1 gauge mode (l = 0), and a family of 3 odd-parity gauge modes (l = 1). The translations and l = 0 gauge modes have nonvanishing, and normalizable, projections into the background gauge, while the odd-parity l = 1 modes have vanishing projection into the background gauge. Among the singular modes, there are an infinite number of modes, irregular at r = 0, which nonetheless satisfy the boundary conditions for finite-energy solutions on the sphere at infinity. I show, by discussing the analogous problem of the axially symmetric solutions of the stationary Einstein equations, that non-normalizable modes are relevant in determining whether a spherically symmetric solution of a nonlinear system has axially symmetric extensions. The analysis of perturbations around the Prasad-Sommerfield solution implies that if an axially symmetric extension exists, it cannot be reached by integration out along a tangent vector defined by a nonvanishing, nonsingular small-perturbation mode of the class explicitly constructed
Directory of Open Access Journals (Sweden)
A. Mubarak
2017-11-01
Full Text Available This paper reports on the preparation of titanium nitride (TiN thin films on carbon steel plates, using cathodic arc evaporation CAE PVD technique. We studied and discussed the effect of various nitrogen gas flow rates on microstructural and mechanical properties of TiN-coated carbon steel plates. The coating properties investigated in this work included the surface morphology, thickness of deposited coating, adhesion between the coating and substrate, coating composition, coating crystallography, hardness and surface characterization using a field emission scanning electron microscope (FE-SEM with energy dispersive X-ray (EDX, Xray diffraction (XRD with glazing incidence angle (GIA technique, scratch tester, hardness testing machine, surface roughness tester and atomic force microscope (AFM. SEM analyses showed that all the films had columnar and dense structures with clearly defined substrate-film interfacial layers. The hardness of TiN-coated carbon steel was noted six times more than the hardness of uncoated one. An increase in nitrogen gas flow rate showed; decrease in the formation of macro-droplets, average roughness (Ra and root-mean-square (RMS values in CAE PVD technique. During XRD-GIA studies, it was observed that by increasing the nitrogen gas flow rate, the main peak [1,1,1] shifted toward the lower angular position. Microhardness of TiN-coated carbon steel showed about six times increase in hardness than the uncoated one. Scratch tester results showed an average adhesion between the coating material and substrate. Thanks to the high resolution power could be observed that by increasing nitrogen gas flow rate there was percentage increase in the bearing ratio while percentage decrease in histogram.
Brissenden, Gina; Impey, C.; Prather, E. E.; Lee, K. M.; CATS
2010-01-01
The Center for Astronomy Education (CAE) has been devoted to improving teaching & learning in Astro 101 by creating research-validated curriculum & assessment instruments for use in Astro 101 & by providing Astro 101 instructors professional development opportunities to increase their pedagogical content knowledge & instructional skills at implementing these curricula & assessment materials. To create sustainability and further expand this work, CAE, in collaboration with other national leaders in astronomy education & research, developed the Collaboration of Astronomy Teaching Scholars (CATS) Program. The primary goals of CATS are to: 1) increase the number of Astro 101 instructors conducting fundamental research in astronomy education 2) increase the amount of research-validated curriculum & assessment instruments available for use in Astro 101 3) increase the number of people prepared to develop & conduct their own CAE Teaching Excellence Workshops In our second year we have concluded a national study assessing the contribution students’ personal characteristics make to student learning gains and the effectiveness of interactive learning strategies. We have results from our classroom research validation study on the use of the "ClassAction” electronic learning system. We have begun creation of an assessment instrument designed specifically for Astro 101 to evaluate the effectiveness of our instruction in improving students’ attitudes & beliefs about science, and which is being informed by several of our studies and community input. We have also begun field-testing of our Solar System Concept Inventory. Additionally research into students’ beliefs and reasoning difficulties on topics in Cosmology is underway. We acknowledge the NSF for funding under Award No. 0715517, a CCLI Phase III Grant for the Collaboration of Astronomy Teaching Scholars (CATS) Program.
Fluxon modes in superconducting multilayers
DEFF Research Database (Denmark)
Pedersen, Niels Falsig; Madsen, Søren Peder
2004-01-01
We show how to construct fluxon modes from plasma modes in the inductively coupled stacked Josephson junctions, and consider some special cases of these fluxon modes analytically. In some cases we can find exact analytical solutions when we choose the bias current in a special way. We also consid...
Energy Technology Data Exchange (ETDEWEB)
Kim, H.-M.; Rutqvist, J.; Ryu, D.-W.; Choi, B.-H.; Sunwoo, C.; Song, W.-K.
2011-07-15
This paper presents a numerical modeling study of coupled thermodynamic, multiphase fluid flow and heat transport associated with underground compressed air energy storage (CAES) in lined rock caverns. Specifically, we explored the concept of using concrete lined caverns at a relatively shallow depth for which constructing and operational costs may be reduced if air tightness and stability can be assured. Our analysis showed that the key parameter to assure long-term air tightness in such a system was the permeability of both the concrete lining and the surrounding rock. The analysis also indicated that a concrete lining with a permeability of less than 1×10{sup -18} m{sup 2} would result in an acceptable air leakage rate of less than 1%, with the operational pressure range between 5 and 8 MPa at a depth of 100 m. It was further noted that capillary retention properties and the initial liquid saturation of the lining were very important. Indeed, air leakage could be effectively prevented when the air-entry pressure of the concrete lining is higher than the operational air pressure and when the lining is kept moist at a relatively high liquid saturation. Our subsequent energy-balance analysis demonstrated that the energy loss for a daily compression and decompression cycle is governed by the air-pressure loss, as well as heat loss by conduction to the concrete liner and surrounding rock. For a sufficiently tight system, i.e., for a concrete permeability off less than 1×10{sup -18} m{sup 2}, heat loss by heat conduction tends to become proportionally more important. However, the energy loss by heat conduction can be minimized by keeping the air-injection temperature of compressed air closer to the ambient temperature of the underground storage cavern. In such a case, almost all the heat loss during compression is gained back during subsequent decompression. Finally, our numerical simulation study showed that CAES in shallow rock caverns is feasible from a leakage
Directory of Open Access Journals (Sweden)
Ruixiong Li
2016-12-01
Full Text Available The compressed air energy storage (CAES system, considered as one method for peaking shaving and load-levelling of the electricity system, has excellent characteristics of energy storage and utilization. However, due to the waste heat existing in compressed air during the charge stage and exhaust gas during the discharge stage, the efficient operation of the conventional CAES system has been greatly restricted. The Kalina cycle (KC and organic Rankine cycle (ORC have been proven to be two worthwhile technologies to fulfill the different residual heat recovery for energy systems. To capture and reuse the waste heat from the CAES system, two systems (the CAES system combined with KC and ORC, respectively are proposed in this paper. The sensitivity analysis shows the effect of the compression ratio and the temperature of the exhaust on the system performance: the KC-CAES system can achieve more efficient operation than the ORC-CAES system under the same temperature of exhaust gas; meanwhile, the larger compression ratio can lead to the higher efficiency for the KC-CAES system than that of ORC-CAES with the constant temperature of the exhaust gas. In addition, the evolutionary multi-objective algorithm is conducted between the thermodynamic and economic performances to find the optimal parameters of the two systems. The optimum results indicate that the solutions with an exergy efficiency of around 59.74% and 53.56% are promising for KC-CAES and ORC-CAES system practical designs, respectively.
Compressional Alfven Eigenmode Similarity Study
Heidbrink, W. W.; Fredrickson, E. D.; Gorelenkov, N. N.; Rhodes, T. L.
2004-11-01
NSTX and DIII-D are nearly ideal for Alfven eigenmode (AE) similarity experiments, having similar neutral beams, fast-ion to Alfven speed v_f/v_A, fast-ion pressure, and shape of the plasma, but with a factor of 2 difference in the major radius. Toroidicity-induced AE with ˜100 kHz frequencies were compared in an earlier study [1]; this paper focuses on higher frequency AE with f ˜ 1 MHz. Compressional AE (CAE) on NSTX have a polarization, dependence on the fast-ion distribution function, frequency scaling, and low-frequency limit that are qualitatively consistent with CAE theory [2]. Global AE (GAE) are also observed. On DIII-D, coherent modes in this frequency range are observed during low-field (0.6 T) similarity experiments. Experiments will compare the CAE stability limits on DIII-D with the NSTX stability limits, with the aim of determining if CAE will be excited by alphas in a reactor. Predicted differences in the frequency splitting Δ f between excited modes will also be used. \\vspace0.25em [1] W.W. Heidbrink, et al., Plasmas Phys. Control. Fusion 45, 983 (2003). [2] E.D. Fredrickson, et al., Princeton Plasma Physics Laboratory Report PPPL-3955 (2004).
Arshad, Muhammad; Seadawy, Aly R.; Lu, Dianchen
2018-01-01
In mono-mode optical fibers, the higher order non-linear Schrödinger equation (NLSE) describes the propagation of enormously short light pulses. We constructed optical solitons and, solitary wave solutions of higher order NLSE mono-mode optical fibers via employing modified extended mapping method which has important applications in Mathematics and physics. Furthermore, the formation conditions are also given on parameters in which optical bright and dark solitons can exist for this media. The moment of the obtained solutions are also given graphically, that helps to realize the physical phenomena's of this model. The modulation instability analysis is utilized to discuss the model stability, which verifies that all obtained solutions are exact and stable. Many other such types of models arising in applied sciences can also be solved by this reliable, powerful and effective method. The method can also be functional to other sorts of higher order nonlinear problems in contemporary areas of research.
Balkatzopoulou, P; Fasoula, S; Gika, H; Nikitas, P; Pappa-Louisi, A
2015-05-29
In the present work the retention of three highly polar and ionizable solutes - uric acid, nicotinic acid and ascorbic acid - was investigated on a mixed-mode reversed-phase and weak anion-exchange (RP/WAX) stationary phase in buffered aqueous acetonitrile (ACN) mobile phases. A U-shaped retention behavior was observed for all solutes with respect to the eluent organic modifier content studied in a range of 5-95% (v/v). This retention behavior clearly demonstrates the presence of a HILIC-type retention mechanism at ACN-rich hydro-organic eluents and an RP-like retention at aqueous-rich hydro-organic eluents. Hence, this column should be promising for application under both RP and HILIC gradient elution modes. For this reason, a series of programmed elution runs were carried out with increasing (RP) and decreasing (HILIC) organic solvent concentration in the mobile phase. This dual gradient process was successfully modeled by two retention models exhibiting a quadratic or a cubic dependence of the logarithm of the solute retention factor (lnk) upon the organic modifier volume fraction (φ). It was found that both models produced by gradient retention data allow the prediction of solute retention times for both types of programmed elution on the mixed-mode column. Four, in the case of the quadratic model, or five, in the case of the cubic model, initial HILIC- and RP-type gradient runs gave satisfactory retention predictions of any similar kind elution program, even with different flow rate, with an overall error of only 2.5 or 1.7%, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.
UTILIZAÇÃO DE SOFTWARE CAD E CAE NO DESENVOLVIMENTO DE PRODUTO SUSTENTÁVEL PARA AQUECIMENTO DE ÁGUA
Directory of Open Access Journals (Sweden)
Jorge Henrique Sales
2014-07-01
Full Text Available Atualmente a engenharia tem preocupação em desenvolvimento de projetos que atendam as necessidades socioambientais. Neste trabalho, apresenta-se um produto que usa o conceito de sustentabilidade visando auxiliar na ação contra alguns dos problemas ambientais que afetam o planeta, sendo grande parte destes associados ao uso irracional de recursos, como energia e a água. O produto utiliza materiais recicláveis para obter um painel solar, denominado de ASAR (Aquecedor Solar Alternativo por Reflexão com a função de aquecer água para uso residencial. Com base do método do modelo de referência, foi feita a modelagem e simulação com ferramentas como o CAD e CAE.
Brissenden, Gina; Impey, C.; Prather, E.; Lee, K.; Duncan, D.
2009-01-01
The Center for Astronomy Education (CAE) has been devoted to improving teaching & learning in Astro 101 by creating research-validated curriculum & assessment instruments for use in Astro 101 & by providing Astro 101 instructors professional development opportunities to increase their pedagogical content knowledge & instructional skills at implementing these curricula & assessment materials. To create sustainability and further expand this work, CAE, in collaboration with other national leaders in astronomy education & research, developed the Collaboration of Astronomy Teaching Scholars (CATS) Program. The primary goals of CATS are to: 1) increase the number of Astro 101 instructors conducting fundamental research in astronomy education 2) increase the amount of research-validated curriculum & assessment instruments available for use in Astro 101 3) increase the number of people prepared to develop & conduct their own CAE Teaching Excellence Workshops In our first year we have concluded a national study assessing the teaching & learning of Astro 101 & the effect of interactive instruction. We have begun the initial analysis of the demographics data of this study. We have begun a classroom research validation study on the use of the "ClassAction” electronic learning system. We have begun to analyze data from two different studies on students’ attitudes & understanding of science to inform the creation of an assessment instrument designed specifically for Astro 101 to evaluate the effectiveness of our instruction in improving students’ attitudes & beliefs about science. We have also begun the development of a Solar System Concept Inventory. Additionally the development of the Solar System Concept Inventory and research into students’ beliefs and reasoning difficulties on topics in Cosmology are well underway. We acknowledge the NSF for funding under Award No. 0715517, a CCLI Phase III Grant for the Collaboration of Astronomy Teaching Scholars (CATS) Program.
Interferometric characterization of few-mode fibers (FMF) for mode-division multiplexing (MDM)
Muliar, Olena; Usuga Castaneda, Mario A.; Rottwitt, Karsten; Lægsgaard, Jesper
2015-01-01
The rapid growth of global data traffic demands the continuous search for new technologies and systems that could increase transmission capacity in optical links and recent experiments show that to do so, it is advantageous to explore new degrees of freedom such as polarization, wavelength or optical modes. Mode division multiplexing (MDM) appears in this context as a promising and viable solution for such capacity increase, since it utilizes multiple spatial modes of an optical fiber as indi...
Mode regularization of the supersymmetric sphaleron and kink: Zero modes and discrete gauge symmetry
International Nuclear Information System (INIS)
Goldhaber, Alfred Scharff; Litvintsev, Andrei; Nieuwenhuizen, Peter van
2001-01-01
To obtain the one-loop corrections to the mass of a kink by mode regularization, one may take one-half the result for the mass of a widely separated kink-antikink (or sphaleron) system, where the two bosonic zero modes count as two degrees of freedom, but the two fermionic zero modes as only one degree of freedom in the sums over modes. For a single kink, there is one bosonic zero mode degree of freedom, but it is necessary to average over four sets of fermionic boundary conditions in order (i) to preserve the fermionic Z 2 gauge invariance ψ→-ψ, (ii) to satisfy the basic principle of mode regularization that the boundary conditions in the trivial and the kink sector should be the same, (iii) that the energy stored at the boundaries cancels and (iv) to avoid obtaining a finite, uniformly distributed energy which would violate cluster decomposition. The average number of fermionic zero-energy degrees of freedom in the presence of the kink is then indeed 1/2. For boundary conditions leading to only one fermionic zero-energy solution, the Z 2 gauge invariance identifies two seemingly distinct 'vacua' as the same physical ground state, and the single fermionic zero-energy solution does not correspond to a degree of freedom. Other boundary conditions lead to two spatially separated ω∼0 solutions, corresponding to one (spatially delocalized) degree of freedom. This nonlocality is consistent with the principle of cluster decomposition for correlators of observables
Asymptotic Method of Solution for a Problem of Construction of Optimal Gas-Lift Process Modes
Directory of Open Access Journals (Sweden)
Fikrat A. Aliev
2010-01-01
Full Text Available Mathematical model in oil extraction by gas-lift method for the case when the reciprocal value of well's depth represents a small parameter is considered. Problem of optimal mode construction (i.e., construction of optimal program trajectories and controls is reduced to the linear-quadratic optimal control problem with a small parameter. Analytic formulae for determining the solutions at the first-order approximation with respect to the small parameter are obtained. Comparison of the obtained results with known ones on a specific example is provided, which makes it, in particular, possible to use obtained results in realizations of oil extraction problems by gas-lift method.
Design and numerical optimization of a mode multiplexer based on few-mode fiber couplers
International Nuclear Information System (INIS)
Xie, Yiwei; Fu, Songnian; Liu, Hai; Zhang, Hailiang; Tang, Ming; Liu, Deming; Shum, P
2013-01-01
Mode division multiplexing (MDM) transmission based on few-mode fibers (FMFs) appears to be an alternative solution for overcoming the capacity limit of single-mode fibers (SMFs). A FMF coupler-based mode division multiplexer/demultiplexer (MMUX/DeMMUX) is proposed and theoretically investigated after the fabricated FMF is characterized. MMUXs/DeMMUXs with a mode contrast ratio (MCR) of more than 20 dB can be obtained for two-mode multiplexing and three-mode multiplexing over a wavelength span of 60 and 10 nm, respectively. We numerically verify the proposed MMUX/DeMMUX which has the advantages of high MCR, easy fabrication and maintenance, and low wavelength dependence. (paper)
Legal and regulatory issues affecting compressed air energy storage
Energy Technology Data Exchange (ETDEWEB)
Hendrickson, P.L.
1981-07-01
Several regulatory and legal issues that can potentially affect implementation of a compressed air energy storage (CAES) system are discussed. This technology involves the compression of air using base load electric power for storage in an underground storage medium. The air is subsequently released and allowed to pass through a turbine to generate electricity during periods of peak demand. The storage media considered most feasible are a mined hard rock cavern, a solution-mined cavern in a salt deposit, and a porous geologic formation (normally an aquifer) of suitable structure. The issues are discussed in four categories: regulatory issues common to most CAES facilities regardless of storage medium, regulatory issues applicable to particular CAES reservoir media, issues related to possible liability from CAES operations, and issues related to acquisition of appropriate property rights for CAES implementation. The focus is on selected federal regulation. Lesser attention is given to state and local regulation. (WHK)
International Nuclear Information System (INIS)
Kimura, Y.; Tokuyama, M.
2016-01-01
The full numerical solutions of the time-convolutionless modecoupling theory (TMCT) equation recently proposed by Tokuyama are compared with those of the ideal mode-coupling theory (MCT) equation based on the Percus- Yevick static structure factor for hard spheres qualitatively and quantitatively. The ergodic to non-ergodic transition at the critical volume fraction φ_c predicted by MCT is also shown to occur even for TMCT. Thus, φ_c of TMCT is shown to be much higher than that of MCT. The dynamics of coherent-intermediate scattering functions and their two-step relaxation process in a β stage are also discussed.
Viscous modes, isocurvature perturbations and CMB initial conditions
Giovannini, Massimo
2015-01-01
When the predecoupling plasma is thermodinamically reversible its fluctuations are classified in terms of the adiabatic and entropic modes. A different category of physical solutions, so far unexplored, arises when the inhomogeneities of the viscosity coefficients induce computable curvature perturbations. The viscous modes are explicitly illustrated and compared with the conventional isocurvature solutions.
Solutions of two-mode Jaynes–Cummings models
Indian Academy of Sciences (India)
variety of problems [2–8] in quantum optics and it predicts many new features in the limit of strong coupling g of the ... mation in quantum mechanics by Sudha Singh and Roy [19,20] can be conveniently used to obtain the ... operators for modes 1 and 2, ˆσii = |i〉〈i| are the level occupation number and. ˆσij = |i〉〈j|(i = j) are the ...
International Nuclear Information System (INIS)
Cavallo, Alfred
2007-01-01
World wind energy resources are substantial, and in many areas, such as the US and northern Europe, could in theory supply all of the electricity demand. However, the remote or challenging location (i.e. offshore) and especially the intermittent character of the wind resources present formidable barriers to utilization on the scale required by a modern industrial economy. All of these technical challenges can be overcome. Long distance transmission is well understood, while offshore wind technology is being developed rapidly. Intermittent wind power can be transformed to a controllable power source with hybrid wind/compressed air energy storage (CAES) systems. The cost of electricity from such hybrid systems (including transmission) is affordable, and comparable to what users in some modern industrial economies already pay for electricity. This approach to intermittent energy integration has many advantages compared to the current strategy of forcing utilities to cope with supply uncertainty and transmission costs. Above all, it places intermittent wind on an equal technical footing with every other generation technology, including nuclear power, its most important long-term competitor
Low-frequency modes with high toroidal mode numbers. A general formulation
International Nuclear Information System (INIS)
Pegoraro, F.; Schep, T.J.
1979-09-01
Low-frequency waves with high toroidal mode numbers in an axisymmetric toroidal configuration are studied. In particular, the relationship between the periodicity constraints imposed by the geometry, magnetic shear and the spatial structure of eigenmodes is investigated. By exploiting the radial translational invariance and the poloidal periodicity of the gyrokinetic and Maxwell equations, the two-dimensional problem can be converted into a one-dimensional one and the mode structure can be expressed in terms of a single extended poloidal variable. This representation is used in the description of electromagnetic modes with phase velocities larger than the ion thermal velocity and with frequencies below the ion gyro-frequency. Trapped particle, curvature and compressional effects are retained. The dispersion equations for drift mode and Alfven-type modes are given in general geometry and simplified solutions are presented in the configuration of a double periodic plane slab. (Auth.)
Analytical solutions of coupled-mode equations for microring ...
Indian Academy of Sciences (India)
equivalent to waveguide and single microring coupled system. The 3 × 3 coupled system is equivalent to waveguide and double microring coupled system. In this paper, we adopt a novel approach for obtaining coupled-mode equations for linearly distributed and circularly distributed multiwaveguide systems with different ...
Spatial stability of jets - the nonaxisymmetric fundamental and reflection modes
International Nuclear Information System (INIS)
Hardee, P.E.
1987-01-01
A spatial stability analysis of the relativistic dispersion relation governing the growth and propagation of harmonic components comprising a perturbation to the surface of a cylindrical jet is performed. The spatial growth of harmonic components associated with the nonaxisymmetric fundamental solution and reflection solutions of several Fourier modes are analyzed. Approximate analytical expressions describing resonant frequencies and wavelengths, and maximum growth rates at resonance applicable to relativistic jets are found from the dispersion relation, and the nature of the resonances is explored. On transonic jets there is only a fundamental solution for each Fourier mode with no resonance or maximum growth rate. On supersonic jets there is a fundamental solution and reflection solutions for each Fourier mode, and each solution contains a resonance at which the growth rate is a maximum. A numerical analysis of the fundamental and first three reflection solutions of the axisymmetric and first three nonaxisymmetric Fourier modes is performed. The numerical analysis is restricted to nonrelativistic flows but otherwise covers a broad range of Mach numbers and jet densities. The numerical results are used along with the analytical results to obtain accurate expressions for resonant frequencies, wavelengths, and growth rates as a function of Mach numnber and jet density. In all cases the fastest spatial growth rate at a given frequency is of harmonic components associated with the fundamental solution of one of the nonaxisymmetric Fourier modes. The application of these results to jet structure and implication of these results for jet structure in extragalactic radio sources are considered. 23 references
Fundamental Solution For The Self-healing Fracture Pulse
Nielsen, S.; Madariaga, R.
We find the analytical solution for a fundamental fracture mode in the form of a self- similar, self-healing pulse. The existence of such a fracture mode was strongly sug- gested by recent numerical findings but, to our knwledge, no formal proof had been proposed up to date. We present a two dimensional, anti-plane solution for fixed rup- ture and healing velocities, that satisfies both wave equation and stress conditions; we argue that such a solution is plausible even in the absence of rate-weakening in the friction, as an alternative to the classic crack solution. In practice, the impulsive mode rather than the expanding crack mode is selected depending on details of fracture initiation, and is therafter self-maintained. We discuss stress concentration, fracture energy, rupture velocity and compare them to the case of a crack. The analytical study is complemented by various numerical examples and comparisons. On more general grounds, we argue that an infinity of marginally stable fracture modes may exist other than the crack solution or the impulseive fracture described here.
Knoll, J; Knoll, B; Miklya, I
1996-01-01
Two breeds of rats, Charles River Wistar [Crl(Wi)Br.] and HSD Wistar [Wistar per LATI (Budapest) Br.], with remarkable difference in learning performance were selected. The rats were trained in the shuttle box with 100 trials per day and the number of conditioned avoidance responses (CARs), the escape failures (EFs) to the unconditioned stimulus and the intersignal reactions (IRs) were counted and evaluated by multi-way analysis of variance (ANOVA). Rats of the Crl (Wi) breed proved to be the 'low performing' (LP) animals and rats of the Wistar per LATI (Budapest) breed the 'high performing' (HP) ones. The HP rats produced higher number of CARs (pPPAP], which enhances action potential-transmitter release coupling in the catecholaminergic neurons, fully antagonized in a dose of 1 mg/kg, tetrabenazine-induced learning depression in HP rats and this dose was ineffective in LP rats. The findings were regarded as further support for the view that endogenous CAE substances regulate catecholaminergic activity in the brain and (-)PPAP acts via this regulation.
Class-A mode-locked lasers: Fundamental solutions
Kovalev, Anton V.; Viktorov, Evgeny A.
2017-11-01
We consider a delay differential equation (DDE) model for mode-locked operation in class-A semiconductor lasers containing both gain and absorber sections. The material processes are adiabatically eliminated as these are considered fast in comparison to the delay time for a long cavity device. We determine the steady states and analyze their bifurcations using DDE-BIFTOOL [Engelborghs et al., ACM Trans. Math. Software 28, 1 (2002)]. Multiple forms of coexistence, transformation, and hysteretic behavior of stable steady states and fundamental periodic regimes are discussed in bifurcation diagrams.
Directory of Open Access Journals (Sweden)
Torsten Karzig
2013-11-01
Full Text Available One-dimensional topological superconductors are known to host Majorana zero modes at domain walls terminating the topological phase. Their non-Abelian nature allows for processing quantum information by braiding operations that are insensitive to local perturbations, making Majorana zero modes a promising platform for topological quantum computation. Motivated by the ultimate goal of executing quantum-information processing on a finite time scale, we study domain walls moving at a constant velocity. We exploit an effective Lorentz invariance of the Hamiltonian to obtain an exact solution of the associated quasiparticle spectrum and wave functions for arbitrary velocities. Essential features of the solution have a natural interpretation in terms of the familiar relativistic effects of Lorentz contraction and time dilation. We find that the Majorana zero modes remain stable as long as the domain wall moves at subluminal velocities with respect to the effective speed of light of the system. However, the Majorana bound state dissolves into a continuous quasiparticle spectrum after the domain wall propagates at luminal or even superluminal velocities. This relativistic catastrophe implies that there is an upper limit for possible braiding frequencies even in a perfectly clean system with an arbitrarily large topological gap. We also exploit our exact solution to consider domain walls moving past static impurities present in the system.
Lee, Jaesun; Achenbach, Jan D; Cho, Younho
2018-03-01
Guided waves can effectively be used for inspection of large scale structures. Surface corrosion is often found as major defect type in large scale structures such as pipelines. Guided wave interaction with surface corrosion can provide useful information for sizing and classification. In this paper, the elastodynamic reciprocity theorem is used to formulate and solve complicated scattering problems in a simple manner. The approach has already been applied to scattering of Rayleigh and Lamb waves by defects to produce closed form solutions of amplitude of scattered waves. In this paper, the scattering of the lowest axially symmetric torsional mode, which is widely used in commercial applications, is analyzed by the reciprocity theorem. In the present paper, the theorem is used to determine the scattering of the lowest torsional mode by a tapered defect that was earlier considered experimentally and numerically by the finite element method. It is shown that by the presented method it is simple to obtain the ratio of amplitudes of scattered torsional modes for a tapered notch. The results show a good agreement with earlier numerical results. The wave field superposition technique in conjunction with the reciprocity theorem simplifies the solution of the scattering problem to yield a closed form solution which can play a significant role in quantitative signal interpretation. Copyright © 2017 Elsevier B.V. All rights reserved.
Yang, Chunlan; Li, Bin; Ge, Mengyu; Zhou, Kaile; Wang, Yanli; Luo, Ju; Ibrahim, Muhammad; Xie, Guanlin; Sun, Guochang
2014-06-04
Inhibitory effect and mode of action of chitosan solution against rice bacterial brown stripe pathogen Acidovorax avenae subsp. avenae (Aaa) strain RS-1 was examined in this study. Result from this study indicated that chitosan solutions at 0.10, 0.20, and 0.40mg/mL inhibited the in vitro growth of Aaa strain RS-1, and in general the inhibitory efficiency increased with the increase of both chitosan concentration and the incubation time. Antibacterial activity of chitosan in this study may be mainly due to the damage of cell membrane, which was evidenced by both the cell lysis observed by transmission electron microscopy, and the increased release of cell materials based on the measurement of cell membrane integrity. Furthermore, chitosan solutions at concentrations of 0.1, 0.2, and 0.4mg/mL markedly inhibited bacterial biofilm formation compared to the control, and the inhibitory effect increased with the increase of chitosan concentration. In addition, quantitative real-time PCR of the 10 secretion system related genes revealed the differential expression of genes in particular ompA/motB, emphasizing the importance of this gene in the response of Aaa strain RS-1 to chitosan stress. These results indicated that the antibacterial mode of action of chitosan may be mainly due to membrane disruption and lysis, reduction of biofilm formation, and gene expression change. Overall, the results clearly indicated that chitosan had the potential to control bacterial brown stripe of rice. Copyright © 2014 Elsevier Ltd. All rights reserved.
Ponderomotive modification of drift tearing modes
International Nuclear Information System (INIS)
Urquijo, G.; Singh, R.; Sen, A.
1997-01-01
The linear characteristics of drift tearing modes are investigated in the presence of a significant background of radio-frequency (RF) waves in the ion cyclotron range of frequencies. The ponderomotive force, arising from the radial gradients in the RF field energy, is found to significantly modify the inner layer solutions of the drift tearing modes. It can have a stabilizing influence, even at moderate RF powers, provided the field energy has a decreasing radial profile at the mode rational surface. (author)
On the role of resonances in double-mode pulsation
International Nuclear Information System (INIS)
Dziembowski, W.; Kovacs, G.
1984-01-01
Simultaneous effects of resonant coupling and non-linear saturation of linear driving mechanism on the finite amplitude solution of multi-modal pulsation problem and on its stability are investigated. Both effects are calculated in the lowest order of approximation in terms of amplitudes. It is shown that the 2:1 resonance between one of the two linearly unstable modes and a higher frequency mode causes double-mode (fundamental and first overtone) pulsation. In a certain range of parameters, such as the frequency mismatch, the linear growth and damping rates, it is the only stable solution of the problem. (author)
Energy Technology Data Exchange (ETDEWEB)
Lessard, R.D.; Blecher, W.A.; Merrick, D.
1981-09-01
The load-following capability of fluidized bed combustion-augmented compressed air energy storage systems was evaluated. The results are presented in two parts. The first part is an Executive Summary which provides a concise overview of all major elements of the study including the conclusions, and, second, a detailed technical report describing the part-load and load following capability of both the pressurized fluid bed combustor and the entire pressurized fluid bed combustor/compressed air energy storage system. The specific tasks in this investigation were to: define the steady-state, part-load operation of the CAES open-bed PFBC; estimate the steady-state, part-load performance of the PFBC/CAES system and evaluate any possible operational constraints; simulate the performance of the PFBC/CAES system during transient operation and assess the load following capability of the system; and establish a start-up procedure for the open-bed PFBC and evaluate the impact of this procedure. The conclusions are encouraging and indicate that the open-bed PFBC/CAES power plant should provide good part-load and transient performance, and should have no major equipment-related constraints, specifically, no major problems associated with the performance or design of either the open-end PFBC or the PFBC/CAES power plant in steady-state, part-load operation are envisioned. The open-bed PFBC/CAES power plant would have a load following capability which would be responsive to electric utility requirements for a peak-load power plant. The open-bed PFBC could be brought to full operating conditions within 15 min after routine shutdown, by employing a hot-start mode of operation. The PFBC/CAES system would be capable of rapid changes in output power (12% of design load per minute) over a wide output power range (25% to 100% of design output). (LCL)
Mode structure and continuum damping of high-n toroidal Alfven eigenmodes
International Nuclear Information System (INIS)
Rosenbluth, M.N.; Berk, H.L.; Van Dam, J.W.; Lindberg, D.M.
1992-02-01
An asymptotic theory is described for calculating the mode structure and continuum damping of short wave-length toroidal Alfven eigenmodes (TAE). The formalism somewhat resembles the treatment used for describing low-frequency toroidal modes with singular structure at a rational surface, where an inner solution, which for the TAE mode has toroidal coupling, is matched to an outer toroidally uncoupled solution. A three-term recursion relation among coupled poloidal harmonic amplitudes is obtained, whose solution gives the structure of the global wavefunction and the complex eigenfrequency, including continuum damping. Both analytic and numerical solutions are presented. The magnitude of the damping is essential for determining the thresholds for instability driven by the spatial gradients of energetic particles (e.g., neutral beam-injected ions or fusion-product alpha particles) contained in a tokamak plasma
Sphalerons, deformed sphalerons and normal modes
International Nuclear Information System (INIS)
Brihaye, Y.; Kunz, J.; Oldenburg Univ.
1992-01-01
Topological arguments suggest that tha Weinberg-Salam model posses unstable solutions, sphalerons, representing the top of energy barriers between inequivalent vacua of the gauge theory. In the limit of vanishing Weinberg angle, such unstable solutions are known: the sphaleron of Klinkhamer and Manton and at large values of the Higgs mass in addition the deformed sphalerons. Here a systematic study of the discrete normal modes about these sphalerons for the full range Higgs mass is presented. The emergence of deformed sphalerons at critical values of the Higgs mass is seem to be related to the crossing of zero of the eigenvalue of the particular normal modes about the sphaleron. 6 figs., 1 tab., 19 refs. (author)
Wave Propagation of Coupled Modes in the DNA Double Helix
International Nuclear Information System (INIS)
Tabi, Conrad B.; Mohamadou, Alidou; Kofane, Timoleon C.
2010-06-01
The dynamics of waves propagating along the DNA molecule is described by the coupled nonlinear Schroedinger equations. We consider both the single and the coupled nonlinear excitation modes, and we discuss their biological implications. Furthermore, the characteristics of the coupled mode solution are discussed and we show that such a solution can describe the local opening observed within the transcription and the replication phenomena. (author)
Toroidal coupling and frequency spectrum of tearing modes
International Nuclear Information System (INIS)
Edery, D.; Samain, A.
1989-05-01
The frequency spectrum of tearing modes is analyzed with the help of a mode coupling model including toroidal effects in the MHD regions and various non linear effects in the resonant layers. In particular it is shown that the sudden damping of the mode rotation and the simultaneous enhancement of the growth rate observed in tokamak, could be explained as a bifurcating solution of the dispersion equation
Adiabatic liquid piston compressed air energy storage
Energy Technology Data Exchange (ETDEWEB)
Petersen, Tage [Danish Technological Institute, Aarhus (Denmark); Elmegaard, B. [Technical Univ. of Denmark. DTU Mechanical Engineering, Kgs. Lyngby (Denmark); Schroeder Pedersen, A. [Technical Univ. of Denmark. DTU Energy Conversion, Risoe Campus, Roskilde (Denmark)
2013-01-15
combination of features may make these systems superior to the ALP-CAES solution. The new systems are delivered by companies such as LightSail Energy and General Compression. Apparently, these new systems use piston compressors/expanders, at least for the prototypes. However, for large scale systems, piston mechanisms are not the most economical solution. In terms of large scale systems, turbo machinery is the only economical solution. 5) Even adiabatic CAES systems seem to add more cost to the electricity than can be accepted in the Danish power system. This added cost is primarily due to the investment in turbine/generator, heat exchangers, and a large quantity of thermal oil. To improve the economy, it would be relevant to investigate the possibility of replacing the thermal oil by water, for example by injecting the water directly into the air flow between the different compression stages to get a direct heat exchange between water and air. This investigation would focus on direct heat exchange in combination with turbo machinery. (Author)
Ion-cyclotron modes in weakly relatavistic plasmas
International Nuclear Information System (INIS)
Venugopal, C.; Kurian, P.J.; Renuka, G.
1994-01-01
We derive a dispersion relation for the perpendicular propagation of ion-cyclotron waves around the ion gyrofrequency Ω + in a weakly relativistic, anisotropic Maxwellian plasma. Using an ordering parameter ε, we separated out two dispersion relations, one of which is independent of the relativistic terms, while the other depends sensitively on them. The solutions of the former dispersion relation yield two modes: a low-frequency (LF) mode with a frequency ω + and a high-frequency (HF) mode with ω > Ω + . The plasma is stable to the propagation of these modes. The latter dispersion relation yields a new LF mode in addition to the modes supported by the non-relativistic dispersion relation. The two LF modes can coalesce to make the plasma unstable. These results are also verified numerically using a standard root solver. (author)
Influence of bio-solution pretreatment on the structure, reactivity and torrefaction of bamboo
International Nuclear Information System (INIS)
Chen, Wei-Hsin; Chu, Yen-Shih; Lee, Wen-Jhy
2017-01-01
Highlights: • A bio-solution of natural organic enzyme-7F (NOE-7F) is used to pretreat bamboo. • The bio-solution removes hemicellulose in powdered bamboo significantly. • Bamboo powder pretreated by bio-solution may be feasible for producing bioethanol. • Penetration of bio-solution into block bamboo controls the pretreatment mechanism. • The homogeneity of bamboo is improved by the bio-solution pretreatment. - Abstract: A bio-solution of natural organic enzyme-7F (NOE-7F) is used to pretreat bamboo, with emphasis on the influence the pretreatment upon the structure, reactivity, and torrefaction of the biomass. Two different operating modes accompanied by five different soaking durations are considered. In Mode 1 the bamboo is ground followed by pretreated by the bio-solution, and an inverse procedure is used in Mode 2. The results indicate that, with the operation of Mode 1, NOE-7F removes hemicellulose in the bamboo significantly, thereby improving the homogeneity of the biomass. This pretreated bamboo may be feasible for enzymatic hydrolysis to produce bioethanol. The penetration of the bio-solution into block bamboo becomes the controlling mechanism under Mode 2 operation, and therefore relatively less hemicellulose is consumed from Mode 2. The ignition and burnout temperatures of the pretreated bamboo are higher than those of the raw bamboo, revealing the lower reactivity and higher storage safety of the former. The atomic H/C and O/C ratios as well as the calorific value of the bamboo are insensitive to the pretreatments, whereas the crystalline structure of cellulose is affected by the bio-solution to a certain extent, regardless of Mode 1 or Mode 2 operation. This suggests that torrefaction is required if the pretreated bamboo is employed as a fuel. The pretreated bamboo with Mode 2 is more suitable for torrefaction because of higher torrefaction severity.
Activity modes selection for project crashing through deterministic simulation
Directory of Open Access Journals (Sweden)
Ashok Mohanty
2011-12-01
Full Text Available Purpose: The time-cost trade-off problem addressed by CPM-based analytical approaches, assume unlimited resources and the existence of a continuous time-cost function. However, given the discrete nature of most resources, the activities can often be crashed only stepwise. Activity crashing for discrete time-cost function is also known as the activity modes selection problem in the project management. This problem is known to be NP-hard. Sophisticated optimization techniques such as Dynamic Programming, Integer Programming, Genetic Algorithm, Ant Colony Optimization have been used for finding efficient solution to activity modes selection problem. The paper presents a simple method that can provide efficient solution to activity modes selection problem for project crashing.Design/methodology/approach: Simulation based method implemented on electronic spreadsheet to determine activity modes for project crashing. The method is illustrated with the help of an example.Findings: The paper shows that a simple approach based on simple heuristic and deterministic simulation can give good result comparable to sophisticated optimization techniques.Research limitations/implications: The simulation based crashing method presented in this paper is developed to return satisfactory solutions but not necessarily an optimal solution.Practical implications: The use of spreadsheets for solving the Management Science and Operations Research problems make the techniques more accessible to practitioners. Spreadsheets provide a natural interface for model building, are easy to use in terms of inputs, solutions and report generation, and allow users to perform what-if analysis.Originality/value: The paper presents the application of simulation implemented on a spreadsheet to determine efficient solution to discrete time cost tradeoff problem.
International Nuclear Information System (INIS)
Ortega-Fernández, Iñigo; Zavattoni, Simone A.; Rodríguez-Aseguinolaza, Javier; D'Aguanno, Bruno; Barbato, Maurizio C.
2017-01-01
Highlights: •A packed bed TES system is proposed for heat recovery in CAES technology. •A CFD-based approach has been developed to evaluate the behaviour of the TES unit. •TES system enhancement and improvement alternatives are also demonstrated. •TES performance evaluated according to the first and second law of thermodynamics. -- Abstract: Compressed air energy storage (CAES) represents a very attracting option to grid electric energy storage. Although this technology is mature and well established, its overall electricity-to-electricity cycle efficiency is lower with respect to other alternatives such as pumped hydroelectric energy storage. A meager heat management strategy in the CAES technology is among the main reasons of this gap of efficiency. In current CAES plants, during the compression stage, a large amount of thermal energy is produced and wasted. On the other hand, during the electricity generation stage, an extensive heat supply is required, currently provided by burning natural gas. In this work, the coupling of both CAES stages through a thermal energy storage (TES) unit is introduced as an effective solution to achieve a noticeable increase of the overall CAES cycle efficiency. In this frame, the thermal energy produced in the compression stage is stored in a TES unit for its subsequent deployment during the expansion stage, realizing an Adiabatic-CAES plant. The present study addresses the conceptual design of a TES system based on a packed bed of gravel to be integrated in an Adiabatic-CAES plant. With this objective, a complete thermo-fluid dynamics model has been developed, including the implications derived from the TES operating under variable-pressure conditions. The formulation and treatment of the high pressure conditions were found being particularly relevant issues. Finally, the model provided a detailed performance and efficiency analysis of the TES system under charge/discharge cyclic conditions including a realistic operative
Rotational modes of a simple Earth model
Seyed-Mahmoud, B.; Rochester, M. G.; Rogister, Y. J. G.
2017-12-01
We study the tilt-over mode (TOM), the spin-over mode (SOM), the free core nutation (FCN), and their relationships to each other using a simple Earth model with a homogeneous and incompressible liquid core and a rigid mantle. Analytical solutions for the periods of these modes as well as that of the Chandler wobble is found for the Earth model. We show that the FCN is the same mode as the SOM of a wobbling Earth. The reduced pressure, in terms of which the vector momentum equation is known to reduce to a scalar second order differential equation (the so called Poincaŕe equation), is used as the independent variable. Analytical solutions are then found for the displacement eigenfucntions in a meridional plane of the liquid core for the aforementioned modes. We show that the magnitude of motion in the mantle during the FCN is comparable to that in the liquid core, hence very small. The displacement eigenfunctions for these aforementioned modes as well as those for the free inner core nutation (FICN), computed numerically, are also given for a three layer Earth model which also includes a rigid but capable of wobbling inner core. We will discuss the slow convergence of the period of the FICN in terms of the characteristic surfaces of the Poincare equation.
Stability analysis of resistive MHD modes via a new numerical matching technique
International Nuclear Information System (INIS)
Furukawa, M.; Tokuda, S.; Zheng, L.-J.
2009-01-01
Full text: Asymptotic matching technique is one of the principal methods for calculating linear stability of resistive magnetohydrodynamics (MHD) modes such as tearing modes. In applying the asymptotic method, the plasma region is divided into two regions: a thin inner layer around the mode-resonant surface and ideal MHD regions except for the layer. If we try to solve this asymptotic matching problem numerically, we meet practical difficulties. Firstly, the inertia-less ideal MHD equation or the Newcomb equation has a regular singular point at the mode-resonant surface, leading to the so-called big and small solutions. Since the big solution is not square-integrable, it needs sophisticated treatment. Even if such a treatment is applied, the matching data or the ratio of small solution to the big one, has been revealed to be sensitive to local MHD equilibrium accuracy and grid structure at the mode-resonant surface by numerical experiments. Secondly, one of the independent solutions in the inner layer, which should be matched onto the ideal MHD solution, is not square-integrable. The response formalism has been adopted to resolve this problem. In the present paper, we propose a new method for computing the linear stability of resistive MHD modes via matching technique, where the plasma region is divided into ideal MHD regions and an inner region with finite width. The matching technique using an inner region with finite width was recently developed for ideal MHD modes in cylindrical geometry, and good performance was shown. Our method extends this idea to resistive MHD modes. In the inner region, the low-beta reduced MHD equations are solved, and the solution is matched onto the solution of the Newcomb equation by using boundary conditions such that the parallel electric field vanishes properly as approaching the computational boundaries. If we use the inner region with finite width, the practical difficulties raised above can be avoided from the beginning. Figure
International Nuclear Information System (INIS)
Mubarak, A.; Hamzah, E.; Toff, M.R.M.
2005-01-01
High-Speed Steel (HSS) is a material that used in various Hi-Tech industries for many reasons. The aim of this study is to investigate the tribological properties of TiN (Titanium Nitride)-coated HSS. Using Physical Vapour Deposition (PVD) Cathodic Arc Evaporation (CAE) technique coated samples. The goal of this work is to determine usefulness of TiN coatings in order to improve tribological properties of HSS, as vastly use in cutting tool industry for various applications. A Pin-on-Disc test showed that the minimum value recorded for friction coefficient was reduced from 0.294 to 0.239 when the nitrogen gas flow rate was increased from 100 sccm to 200 sccm. The decrease in friction coefficient resulted from the reduction in macrodroplets by increasing the nitrogen gas flow rate during deposition. The worn surface morphology of the TiN coated HSS was observed on a Field Emission Scanning Electron Microscope (FE-SEM), and the elemental composition on the wear scar were investigated by means of EDXS. (Author)
International Nuclear Information System (INIS)
Salgi, Georges; Lund, Henrik
2008-01-01
In 2005, wind power supplied 19% of the 36 TWh annual electricity demand in Denmark, while 50% was produced at combined heat-and-power plants (CHP). The installed wind-turbine capacity in Western Denmark exceeds the local demand at certain points in time. So far, excess production has been exported to neighbouring countries. However, plans to expand wind power both in Denmark and in its neighbouring countries could restrain the export option and create transmission congestion challenges. This results in a need to increase the flexibility of the local electricity-system. Compressed-Air Energy-Storage (CAES) has been proposed as a potential solution for levelling fluctuating wind-power production and maintaining a system balance. This paper analyses the energy-balance effects of adding CAES to the Western Danish energy-system. Results show that even with an unlimited CAES plant capacity, excess power production is not eliminated because of the high percentage of CHP production. The optimal wind-power penetration for maximum CAES operation is found to be around 55%. The minimum storage size for CAES to fully eliminate condensing power plants operation in the optimized system is over 500 GWh, which corresponds to a cavern volume of around 234 Mm 3 at an average pressure of 60 bar. Such a storage size would be technically and economically unfeasible. The analysis, however, did not include the potential role of a CAES plant in regulating the power services. (author)
Soliton solutions in a diatomic lattice system
International Nuclear Information System (INIS)
Yajima, Nobuo; Satsuma, Junkichi.
1979-04-01
A continuum limit is considered for a diatomic lattice system with a cubic nonlinearity. A long wave equation describing the interaction of acoustic and optical modes is obtained. It reduces, in certain approximations, to equations having coupled wave solutions. The solutions exhibit trapping of an optical mode by an acoustic soliton. The form of the trapped optical wave depends on the mass ratio of adjacent particles in the diatomic lattice. (author)
Interferometric characterization of few-mode fibers (FMF) for mode-division multiplexing (MDM)
DEFF Research Database (Denmark)
Muliar, Olena; Usuga Castaneda, Mario A.; Rottwitt, Karsten
2015-01-01
), commonly used in a MDM scenario. This experimental technique requires the use of a Mach-Zehnder interferometer, where the reference's path length is controlled by an optical delay line. The interference between the output beams of reference and fiber under test (FUT) is recorded on a CCD camera......The rapid growth of global data traffic demands the continuous search for new technologies and systems that could increase transmission capacity in optical links and recent experiments show that to do so, it is advantageous to explore new degrees of freedom such as polarization, wavelength...... or optical modes. Mode division multiplexing (MDM) appears in this context as a promising and viable solution for such capacity increase, since it utilizes multiple spatial modes of an optical fiber as individual communication channels for data transmission. In order to evaluate its performance, a MDM system...
Jacobian elliptic wave solutions in an anharmonic molecular crystal model
International Nuclear Information System (INIS)
Teh, C.G.R.; Lee, B.S.; Koo, W.K.
1997-07-01
Explicit Jacobian elliptic wave solutions are found in the anharmonic molecular crystal model for both the continuum limit and discrete modes. This class of wave solutions include the famous pulse-like and kink-like solitary modes. We would also like to report on the existence of some highly discrete staggered solitary wave modes not found in the continuum limit. (author). 9 refs, 1 fig
Directory of Open Access Journals (Sweden)
Meerovitch K
2013-06-01
Full Text Available Karen Meerovitch,1 Gail Torkildsen,2 John Lonsdale,3 Heidi Goldfarb,4 Teresa Lama,1 Garth Cumberlidge,1 George W Ousler III5 1Mimetogen Pharmaceuticals Inc, Montreal, QC, Canada; 2Andover Eye Associates, Andover, MA, USA; 3Central Maine Eye Care, Lewiston, ME, USA; 4SDC, Tempe, AZ, USA; 5Ora Inc, Andover, MA, USA Purpose: To evaluate the safety and efficacy of ophthalmic MIM-D3, a tyrosine kinase TrkA receptor agonist, in patients with dry eye. Design: A prospective, two-center, randomized, double-masked, placebo-controlled Phase 2 study. Methods: A total of 150 dry eye patients were randomized 1:1:1 to study medication (1% MIM-D3, 5% MIM-D3, or placebo and dosed twice daily (BID for 28 days. Key eligibility criteria included exacerbation in corneal staining and ocular discomfort in the Controlled Adverse Environment (CAESM on two visits, separated by 1 week of BID dosing with artificial tears. Safety and efficacy were evaluated at baseline, throughout treatment, and for 2 weeks post-treatment. The pre-specified primary outcome measures were fluorescein corneal staining post-CAE at day 28 and diary worst symptom scores over 28 days. Secondary outcomes included the pre-, post-, and the change from pre- to post-CAE fluorescein and lissamine green staining in both corneal and conjunctival regions, as well as individual diary symptoms. Results: The prespecified primary endpoints were not met. Compared with placebo, fluorescein corneal staining at day 28 was significantly improved (P < 0.05 in the 1% MIM-D3 group for the assessment of change from pre-CAE to post-CAE. In addition, following CAE exposure, patients in the 1% MIM-D3 group showed significant improvements versus placebo (P < 0.05 in inferior fluorescein and lissamine green staining after 14 and 28 days. Compared with placebo, patients in the 5% MIM-D3 group reported significantly lower daily diary scores for ocular dryness (P < 0.05. In a subgroup defined by higher symptom scores during
Analýza teplotního profilu hot bed a hot end u 3D tiskárny pomocí CAE
Severa, Tomáš
2014-01-01
Předkládaná diplomová práce se zabývá 3D tiskem na nekomerčních 3D tiskárnách typu RepRap a materiály, které se používají při tisku. Výstupem této práce je stručný úvod do problematiky 3D tisku, teorie šíření tepla a rozbor dvou nejdůležitějších částí tiskárny hot bed a hot end. K analýze a optimalizaci teplotního profilu hot bed a hot end jsou použity systémy pro podporu inženýrských prací CAD a CAE, SolidWorks a SolidWorks Flow Simulation. This master‘s thesis deals with 3D printing for ...
Delay differential equations for mode-locked semiconductor lasers.
Vladimirov, Andrei G; Turaev, Dmitry; Kozyreff, Gregory
2004-06-01
We propose a new model for passive mode locking that is a set of ordinary delay differential equations. We assume a ring-cavity geometry and Lorentzian spectral filtering of the pulses but do not use small gain and loss and weak saturation approximations. By means of a continuation method, we study mode-locking solutions and their stability. We find that stable mode locking can exist even when the nonlasing state between pulses becomes unstable.
On the stability of non-supersymmetric supergravity solutions
Imaanpur, Ali; Zameni, Razieh
2017-09-01
We examine the stability of some non-supersymmetric supergravity solutions that have been found recently. The first solution is AdS5 ×M6, for M6 an stretched CP3. We consider breathing and squashing mode deformations of the metric, and find that the solution is stable against small fluctuations of this kind. Next we consider type IIB solution of AdS2 ×M8, where the compact space is a U (1) bundle over N (1 , 1). We study its stability under the deformation of M8 and the 5-form flux. In this case we also find that the solution is stable under small fluctuation modes of the corresponding deformations.
On the stability of non-supersymmetric supergravity solutions
Directory of Open Access Journals (Sweden)
Ali Imaanpur
2017-09-01
Full Text Available We examine the stability of some non-supersymmetric supergravity solutions that have been found recently. The first solution is AdS5×M6, for M6 an stretched CP3. We consider breathing and squashing mode deformations of the metric, and find that the solution is stable against small fluctuations of this kind. Next we consider type IIB solution of AdS2×M8, where the compact space is a U(1 bundle over N(1,1. We study its stability under the deformation of M8 and the 5-form flux. In this case we also find that the solution is stable under small fluctuation modes of the corresponding deformations.
Design and Implementation of Dual-Mode Wireless Video Monitoring System
Directory of Open Access Journals (Sweden)
BAO Song-Jian
2014-10-01
Full Text Available Dual-mode wireless video transmission has two major problems. Firstly, one is time delay difference bringing about asynchronous reception decoding frame error phenomenon; secondly, dual-mode network bandwidth inconformity causes scheduling problem. In order to solve above two problems, a kind of TD-SCDMA/CDMA20001x dual-mode wireless video transmission design method is proposed. For the solution of decoding frame error phenomenon, the design puts forward adding frame identification and packet preprocessing at the sending and synchronizing combination at the receiving end. For the solution of scheduling problem, the wireless communication channel cooperative work and video data transmission scheduling management algorithm is proposed in the design.
Modified Block Newton method for the lambda modes problem
Energy Technology Data Exchange (ETDEWEB)
González-Pintor, S., E-mail: segonpin@isirym.upv.es [Departamento de Ingeniería Química y Nuclear, Universidad Politécnica de Valencia, Camino de Vera 14, 46022 Valencia (Spain); Ginestar, D., E-mail: dginestar@mat.upv.es [Instituto de Matemática Multidisciplinar, Universidad Politécnica de Valencia, Camino de Vera 14, 46022 Valencia (Spain); Verdú, G., E-mail: gverdu@iqn.upv.es [Departamento de Ingeniería Química y Nuclear, Universidad Politécnica de Valencia, Camino de Vera 14, 46022 Valencia (Spain)
2013-06-15
Highlights: ► The Modal Method is based on expanding the solution in a set of dominant modes. ► Updating the set of dominant modes improve its performance. ► A Modified Block Newton Method, which use previous calculated modes, is proposed. ► The method exhibits a very good local convergence with few iterations. ► Good performance results are also obtained for heavy perturbations. -- Abstract: To study the behaviour of nuclear power reactors it is necessary to solve the time dependent neutron diffusion equation using either a rectangular mesh for PWR and BWR reactors or a hexagonal mesh for VVER reactors. This problem can be solved by means of a modal method, which uses a set of dominant modes to expand the neutron flux. For the transient calculations using the modal method with a moderate number of modes, these modes must be updated each time step to maintain the accuracy of the solution. The updating modes process is also interesting to study perturbed configurations of a reactor. A Modified Block Newton method is studied to update the modes. The performance of the Newton method has been tested for a steady state perturbation analysis of two 2D hexagonal reactors, a perturbed configuration of the IAEA PWR 3D reactor and two configurations associated with a boron dilution transient in a BWR reactor.
Application of CAD/CAE class systems to aerodynamic analysis of electric race cars
Grabowski, L.; Baier, A.; Buchacz, A.; Majzner, M.; Sobek, M.
2015-11-01
Aerodynamics is one of the most important factors which influence on every aspect of a design of a car and car driving parameters. The biggest influence aerodynamics has on design of a shape of a race car body, especially when the main objective of the race is the longest distance driven in period of time, which can not be achieved without low energy consumption and low drag of a car. Designing shape of the vehicle body that must generate the lowest possible drag force, without compromising the other parameters of the drive. In the article entitled „Application of CAD/CAE class systems to aerodynamic analysis of electric race cars” are being presented problems solved by computer analysis of cars aerodynamics and free form modelling. Analysis have been subjected to existing race car of a Silesian Greenpower Race Team. On a basis of results of analysis of existence of Kammback aerodynamic effect innovative car body were modeled. Afterwards aerodynamic analysis were performed to verify existence of aerodynamic effect for innovative shape and to recognize aerodynamics parameters of the shape. Analysis results in the values of coefficients and aerodynamic drag forces. The resulting drag forces Fx, drag coefficients Cx(Cd) and aerodynamic factors Cx*A allowed to compare all of the shapes to each other. Pressure distribution, air velocities and streams courses were useful in determining aerodynamic features of analyzed shape. For aerodynamic tests was used Ansys Fluent CFD software. In a paper the ways of surface modeling with usage of Realize Shape module and classic surface modeling were presented. For shapes modeling Siemens NX 9.0 software was used. Obtained results were used to estimation of existing shapes and to make appropriate conclusions.
Digital Sliding Mode Control of Anti-Lock Braking System
Directory of Open Access Journals (Sweden)
MITIC, D. B.
2013-02-01
Full Text Available The control of anti-lock braking system is a great challenge, because of the nonlinear and complex characteristics of braking dynamics, unknown parameters of vehicle environment and system parameter variations. Using some of robust control methods, such as sliding mode control, can be a right solution for these problems. In this paper, we introduce a novel approach to design of ABS controllers, which is based on digital sliding mode control with only input/output measurements. The relay term of the proposed digital sliding mode control is filtered through digital integrator, reducing the chattering phenomenon in that way, and the additional signal of estimated modelling error is introduced into control algorithm to enhance the system steady-state accuracy. The given solution was verified in real experimental framework and the obtained results were compared with the results of implementation of two other digital sliding mode control algorithms. It is shown that it gives better system response, higher steady-state accuracy and smaller chattering.
Tearing modes in toroidal geometry
International Nuclear Information System (INIS)
Connor, J.W.; Cowley, S.C.; Hastie, R.J.; Hender, T.C.; Hood, A.; Martin, T.J.
1988-01-01
The separation of the cylindrical tearing mode stability problem into a resistive resonant layer calculation and an external marginal ideal magnetohydrodynamic (MHD) calculation (Δ' calculation) is generalized to axisymmetric toroidal geometry. The general structure of this separation is analyzed and the marginal ideal MHD information (the toroidal generalization of Δ') required to discuss stability is isolated. This can then, in principle, be combined with relevant resonant layer calculations to determine tearing mode growth rates in realistic situations. Two examples are given: the first is an analytic treatment of toroidally coupled (m = 1, n = 1) and (m = 2, n = 1) tearing modes in a large aspect ratio torus; the second, a numerical treatment of the toroidal coupling of three tearing modes through finite pressure effects in a large aspect ratio torus. In addition, the use of a coupling integral approach for determining the stability of coupled tearing modes is discussed. Finally, the possibility of using initial value resistive MHD codes in realistic toroidal geometry to determine the necessary information from the ideal MHD marginal solution is discussed
Analysis of current diffusive ballooning mode
International Nuclear Information System (INIS)
Yagi, M.; Azumi, M.; Itoh, K.; Itoh, S.; Fukuyama, A.
1993-04-01
The current diffusive ballooning mode is analysed in the tokamak plasma. This mode is destabilized by the current diffusivity (i.e., the electron viscosity) and stabilized by the thermal conductivity and ion viscosity. By use of the ballooning transformation, the eigenmode equation is solved. Analytic solution is obtained by the strong ballooning limit. Numerical calculation is also performed to confirm the analytic theory. The growth rate of the mode and the mode structure are analysed. The stability boundary is derived in terms of the current diffusivity, thermal conductivity, ion viscosity and the pressure gradient for the given shear parameter. This result is applied to express the thermal conductivity in terms of the pressure gradient, magnetic configurational parameters (such as the safety factor, shear and aspect ratio) and the Prandtl numbers. (author)
Solvent density mode instability in non-polar solutions
Indian Academy of Sciences (India)
and excited states of the solute with the compressibility and solvent structure is found to have .... The organization of the rest of the paper is as follows. ...... For the ground state term, as C2 is nearly flat at qσ = q0 = 2π, we can safely ignore.
Spatial Fourier modes controlling Navier-Stokes flow
International Nuclear Information System (INIS)
Treve, Y.M.
1982-01-01
As shown by Foias and Prodi in the limit of infinite times the solutions of the two-dimensional Navier-Stokes equations depend only on a finite number of modes, a number for which rigorous estimates can be obtained. A survey of these results is given together with further developments, notably in connection with the numerical approximation to the exact solutions. (Auth.)
Applications of sliding mode control in science and engineering
Lien, Chang-Hua
2017-01-01
Gathering 20 chapters contributed by respected experts, this book reports on the latest advances in and applications of sliding mode control in science and engineering. The respective chapters address applications of sliding mode control in the broad areas of chaos theory, robotics, electrical engineering, physics, chemical engineering, memristors, mechanical engineering, environmental engineering, finance, and biology. Special emphasis has been given to papers that offer practical solutions, and which examine design and modeling involving new types of sliding mode control such as higher order sliding mode control, terminal sliding mode control, super-twisting sliding mode control, and integral sliding mode control. This book serves as a unique reference guide to sliding mode control and its recent applications for graduate students and researchers with a basic knowledge of electrical and control systems engineering.
Orbital angular momentum of general astigmatic modes
International Nuclear Information System (INIS)
Visser, Jorrit; Nienhuis, Gerard
2004-01-01
We present an operator method to obtain complete sets of astigmatic Gaussian solutions of the paraxial wave equation. In case of general astigmatism, the astigmatic intensity and phase distribution of the fundamental mode differ in orientation. As a consequence, the fundamental mode has a nonzero orbital angular momentum, which is not due to phase singularities. Analogous to the operator method for the quantum harmonic oscillator, the corresponding astigmatic higher-order modes are obtained by repeated application of raising operators on the fundamental mode. The nature of the higher-order modes is characterized by a point on a sphere, in analogy with the representation of polarization on the Poincare sphere. The north and south poles represent astigmatic Laguerre-Gaussian modes, similar to circular polarization on the Poincare sphere, while astigmatic Hermite-Gaussian modes are associated with points on the equator, analogous to linear polarization. We discuss the propagation properties of the modes and their orbital angular momentum, which depends on the degree of astigmatism and on the location of the point on the sphere
Component mode synthesis in structural dynamics
International Nuclear Information System (INIS)
Reddy, G.R.; Vaze, K.K.; Kushwaha, H.S.
1993-01-01
In seismic analysis of Nuclear Reactor Structures and equipments eigen solution requires large computer time. Component mode synthesis is an efficient technique with which one can evaluate dynamic characteristics of a large structure with minimum computer time. Due to this reason it is possible to do a coupled analysis of structure and equipment which takes into account the interaction effects. Basically in this the method large size structure is divided into small substructures and dynamic characteristics of individual substructure are determined. The dynamic characteristics of entire structure are evaluated by synthesising the individual substructure characteristics. Component mode synthesis has been applied in this paper to the analysis of a tall heavy water upgrading tower. Use of fixed interface normal modes, constrained modes, attachment modes in the component mode synthesis using energy principle and using Ritz vectors have been discussed. The validity of this method is established by solving fixed-fixed beam and comparing the results obtained by conventional and classical method. The eigen value problem has been solved using simultaneous iteration method. (author)
Finite-Length Diocotron Modes in a Non-neutral Plasma Column
Walsh, Daniel; Dubin, Daniel
2017-10-01
Diocotron modes are 2D distortions of a non-neutral plasma column that propagate azimuthally via E × B drifts. While the infinite-length theory of diocotron modes is well-understood for arbitrary azimuthal mode number l, the finite-length mode frequency is less developed (with some exceptions), and is naturally of relevance to experiments. In this poster, we present an approach to address finite length effects, such as temperature dependence of the mode frequency. We use a bounce-averaged solution to the Vlasov Equation, in which the Vlasov Equation is solved using action-angle variables of the unperturbed Hamiltonian. We write the distribution function as a Fourier series in the bounce-angle variable ψ, keeping only the bounce-averaged term. We demonstrate a numerical solution to this equation for a realistic plasma with a finite Debye Length, compare to the existing l = 1 theory, and discuss possible extensions of the existing theory to l ≠ 1 . Supported by NSF/DOE Partnership Grants PHY1414570 and DESC0002451.
Stationary localized modes of the quintic nonlinear Schroedinger equation with a periodic potential
International Nuclear Information System (INIS)
Alfimov, G. L.; Konotop, V. V.; Pacciani, P.
2007-01-01
We consider localized modes (bright solitons) of the one-dimensional quintic nonlinear Schroedinger equation with a periodic potential, describing several mean-field models of low-dimensional condensed gases. In the case of attractive nonlinearity we deduce sufficient conditions for collapse. We show that there exist spatially localized modes with arbitrarily large numbers of particles. We study such solutions in the semi-infinite gap (attractive case) and in the first gap (attractive and repulsive cases), and show that a nonzero minimum value of the number of particles is necessary for a localized mode to be created. In the limit of large negative frequencies (attractive case) we observe quantization of the number of particles of the stationary modes. Such solutions can be interpreted as coupled Townes solitons and appear to be stable. The modes in the first gap have numbers of particles infinitely growing with frequencies approaching one of the gap edges, which is explained by the power decay of the modes. Stability of the localized modes is discussed
Institute of Scientific and Technical Information of China (English)
You-wen LIU; Chao XIE; Chun-zhi JIANG; Qi-hong FANG
2010-01-01
In this paper,the analytical solution of stress field for a strained reinforcement layer bonded to a lip-shaped crack under a remote mode Ⅲ uniform load and a concentrated load is obtained explicitly in the series form by using the technical of conformal mapping and the method of analytic continuation.The effects of material combinations,bond of interface and geometric configurations on interfacial stresses generated by eigenstrain,remote load and concentrated load are studied.The results show that the stress concentration and interfacial stresses can be reduced by rational material combinations and geometric configurations designs for different load forms.
Localized solutions for a nonlocal discrete NLS equation
International Nuclear Information System (INIS)
Ben, Roberto I.; Cisneros Ake, Luís; Minzoni, A.A.; Panayotaros, Panayotis
2015-01-01
We study spatially localized time-periodic solutions of breather type for a cubic discrete NLS equation with a nonlocal nonlinearity that models light propagation in a liquid crystal waveguide array. We show the existence of breather solutions in the limit where both linear and nonlinear intersite couplings vanish, and in the limit where the linear coupling vanishes with arbitrary nonlinear intersite coupling. Breathers of this nonlocal regime exhibit some interesting features that depart from what is seen in the NLS breathers with power nonlinearity. One property we see theoretically is the presence of higher amplitude at interfaces between sites with zero and nonzero amplitude in the vanishing linear coupling limit. A numerical study also suggests the presence of internal modes of orbitally stable localized modes. - Highlights: • Show existence of spatially localized solutions in nonlocal discrete NLS model. • Study spatial properties of localized solutions for arbitrary nonlinear nonlocal coupling. • Present numerical evidence that nonlocality leads to internal modes around stable breathers. • Present theoretical and numerical evidence for amplitude maxima at interfaces
Localized solutions for a nonlocal discrete NLS equation
Energy Technology Data Exchange (ETDEWEB)
Ben, Roberto I. [Instituto de Desarrollo Humano, Universidad Nacional de General Sarmiento, J.M. Gutiérrez 1150, 1613 Los Polvorines (Argentina); Cisneros Ake, Luís [Department of Mathematics, ESFM, Instituto Politécnico Nacional, Unidad Profesional Adolfo López Mateos Edificio 9, 07738 México D.F. (Mexico); Minzoni, A.A. [Depto. Matemáticas y Mecánica, I.I.M.A.S.-U.N.A.M., Apdo. Postal 20-726, 01000 México D.F. (Mexico); Panayotaros, Panayotis, E-mail: panos@mym.iimas.unam.mx [Depto. Matemáticas y Mecánica, I.I.M.A.S.-U.N.A.M., Apdo. Postal 20-726, 01000 México D.F. (Mexico)
2015-09-04
We study spatially localized time-periodic solutions of breather type for a cubic discrete NLS equation with a nonlocal nonlinearity that models light propagation in a liquid crystal waveguide array. We show the existence of breather solutions in the limit where both linear and nonlinear intersite couplings vanish, and in the limit where the linear coupling vanishes with arbitrary nonlinear intersite coupling. Breathers of this nonlocal regime exhibit some interesting features that depart from what is seen in the NLS breathers with power nonlinearity. One property we see theoretically is the presence of higher amplitude at interfaces between sites with zero and nonzero amplitude in the vanishing linear coupling limit. A numerical study also suggests the presence of internal modes of orbitally stable localized modes. - Highlights: • Show existence of spatially localized solutions in nonlocal discrete NLS model. • Study spatial properties of localized solutions for arbitrary nonlinear nonlocal coupling. • Present numerical evidence that nonlocality leads to internal modes around stable breathers. • Present theoretical and numerical evidence for amplitude maxima at interfaces.
Regularized quasinormal modes for plasmonic resonators and open cavities
Kamandar Dezfouli, Mohsen; Hughes, Stephen
2018-03-01
Optical mode theory and analysis of open cavities and plasmonic particles is an essential component of optical resonator physics, offering considerable insight and efficiency for connecting to classical and quantum optical properties such as the Purcell effect. However, obtaining the dissipative modes in normalized form for arbitrarily shaped open-cavity systems is notoriously difficult, often involving complex spatial integrations, even after performing the necessary full space solutions to Maxwell's equations. The formal solutions are termed quasinormal modes, which are known to diverge in space, and additional techniques are frequently required to obtain more accurate field representations in the far field. In this work, we introduce a finite-difference time-domain technique that can be used to obtain normalized quasinormal modes using a simple dipole-excitation source, and an inverse Green function technique, in real frequency space, without having to perform any spatial integrations. Moreover, we show how these modes are naturally regularized to ensure the correct field decay behavior in the far field, and thus can be used at any position within and outside the resonator. We term these modes "regularized quasinormal modes" and show the reliability and generality of the theory by studying the generalized Purcell factor of dipole emitters near metallic nanoresonators, hybrid devices with metal nanoparticles coupled to dielectric waveguides, as well as coupled cavity-waveguides in photonic crystals slabs. We also directly compare our results with full-dipole simulations of Maxwell's equations without any approximations, and show excellent agreement.
Mode and climatic factors effect on energy losses in transient heat modes of transmission lines
Bigun, A. Ya; Sidorov, O. A.; Osipov, D. S.; Girshin, S. S.; Goryunov, V. N.; Petrova, E. V.
2018-01-01
Electrical energy losses increase in modern grids. The losses are connected with an increase in consumption. Existing models of electric power losses estimation considering climatic factors do not allow estimating the cable temperature in real time. Considering weather and mode factors in real time allows to meet effectively and safely the consumer’s needs to minimize energy losses during transmission, to use electric power equipment effectively. These factors increase an interest in the evaluation of the dynamic thermal mode of overhead transmission lines conductors. The article discusses an approximate analytic solution of the heat balance equation in the transient operation mode of overhead lines based on the least squares method. The accuracy of the results obtained is comparable with the results of solving the heat balance equation of transient thermal mode with the Runge-Kutt method. The analysis of mode and climatic factors effect on the cable temperature in a dynamic thermal mode is presented. The calculation of the maximum permissible current for variation of weather conditions is made. The average electric energy losses during the transient process are calculated with the change of wind, air temperature and solar radiation. The parameters having the greatest effect on the transmission capacity are identified.
NCBI nr-aa BLAST: CBRC-SCER-06-0000 [SEVENS
Lifescience Database Archive (English)
Full Text Available CBRC-SCER-06-0000 emb|CAE52258.1| Ste2p [Saccharomyces cerevisiae] emb|CAE52260.1| Ste2p [Saccharo...myces cerevisiae] emb|CAE52264.1| Ste2p [Saccharomyces cerevisiae] emb|CAE52265.1| Ste2p [Saccharo...myces cerevisiae] emb|CAE52267.1| Ste2p [Saccharomyces cerevisiae] emb|CAE52268.1| Ste2p [Saccharomyces... cerevisiae] emb|CAE52269.1| Ste2p [Saccharomyces cerevisiae] emb|CAE52271.1| Ste2p [Saccharo...myces cerevisiae] emb|CAE52273.1| Ste2p [Saccharomyces cerevisiae] CAE52258.1 0.0 98% ...
Fermionic quasinormal modes for two-dimensional Horava-Lifshitz black holes
Energy Technology Data Exchange (ETDEWEB)
Stetsko, M.M. [Ivan Franko National University of Lviv, Department for Theoretical Physics, Lviv (Ukraine)
2017-06-15
To obtain fermionic quasinormal modes, the Dirac equation for two types of black holes is investigated. It is shown that two different geometries lead to distinctive types of quasinormal modes, while the boundary conditions imposed on the solutions in both cases are identical. For the first type of black hole, the quasinormal modes have continuous spectrum with negative imaginary part that provides the stability of perturbations. For the second type of the black hole, the quasinormal modes have a discrete spectrum and are completely imaginary. (orig.)
Piezoelectric Energy Harvesting Solutions
Caliò, Renato; Rongala, Udaya Bhaskar; Camboni, Domenico; Milazzo, Mario; Stefanini, Cesare; de Petris, Gianluca; Oddo, Calogero Maria
2014-01-01
This paper reviews the state of the art in piezoelectric energy harvesting. It presents the basics of piezoelectricity and discusses materials choice. The work places emphasis on material operating modes and device configurations, from resonant to non-resonant devices and also to rotational solutions. The reviewed literature is compared based on power density and bandwidth. Lastly, the question of power conversion is addressed by reviewing various circuit solutions. PMID:24618725
Surface vibrational modes in disk-shaped resonators.
Dmitriev, A V; Gritsenko, D S; Mitrofanov, V P
2014-03-01
The natural frequencies and distributions of displacement components for the surface vibrational modes in thin isotropic elastic disks are calculated. In particular, the research is focused on even solutions for low-lying resonant vibrations with large angular wave numbers. Several families of modes are found which are interpreted as modified surface modes of an infinitely long cylinder and Lamb modes of a plate. The results of calculation are compared with the results of the experimental measurements of vibrational modes generated by means of resonant excitation in duraluminum disk with radius of ≈90 mm and thickness of 16 mm in the frequency range of 130-200 kHz. An excellent agreement between the calculated and measured frequencies is found. Measurements of the structure of the resonant peaks show splitting of some modes. About a half of the measured modes has splitting Δfsplit/fmode at the level of the order of 10(-5). The Q-factors of all modes measured in vacuum lie in the interval (2…3)×10(5). This value is typical for duraluminum mechanical resonators in the ultrasonic frequency range. Copyright © 2013 Elsevier B.V. All rights reserved.
Anjos, Pedro H. A.; Lira, Sérgio A.; Miranda, José A.
2018-04-01
We examine the formation of interfacial patterns when a magnetic liquid droplet (ferrofluid, or a magnetorheological fluid), surrounded by a nonmagnetic fluid, is subjected to a radial magnetic field in a Hele-Shaw cell. By using a vortex-sheet formalism, we find exact stationary solutions for the fluid-fluid interface in the form of n -fold polygonal shapes. A weakly nonlinear, mode-coupling method is then utilized to find time-evolving perturbative solutions for the interfacial patterns. The stability of such nonzero surface tension exact solutions is checked and discussed, by trying to systematically approach the exact stationary shapes through perturbative solutions containing an increasingly larger number of participating Fourier modes. Our results indicate that the exact stationary solutions of the problem are stable, and that a good matching between exact and perturbative shape solutions is achieved just by using a few Fourier modes. The stability of such solutions is substantiated by a linearization process close to the stationary shape, where a system of mode-coupling equations is diagonalized, determining the eigenvalues which dictate the stability of a fixed point.
International Nuclear Information System (INIS)
Zhang Hai-Yan; Yu Jian-Bo
2011-01-01
Excitation and propagation of Lamb waves by using rectangular and circular piezoelectric transducers surface-bonded to an isotropic plate are investigated in this work. Analytical stain wave solutions are derived for the two transducer shapes, giving the responses of these transducers in Lamb wave fields. The analytical study is supported by a numerical simulation using the finite element method. Symmetric and antisymmetric components in the wave propagation responses are inspected in detail with respect to test parameters such as the transducer geometry, the length and the excitation frequency. By placing only one piezoelectric transducer on the top or the bottom surface of the plate and weakening the strength of one mode while enhancing the strength of the other modes to find the centre frequency, with which the peak wave amplitude ratio between the S0 and A0 modes is maximum, a single mode excitation from the multiple modes of the Lamb waves can be achieved approximately. Experimental data are presented to show the validity of the analyses. The results are used to optimize the Lamb wave detection system. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)
Acoustic modes in dense dusty plasmas
International Nuclear Information System (INIS)
Avinash, K.; Bhattacharjee, A.; Hu, S.
2002-01-01
Properties of acoustic modes in high dust density dusty plasmas are studied. The solutions of fluid equations for electrons, ions, and dust grains with collisional and ionization effects are solved along with an equation for grain charging. The high dust density effects on the acoustic modes are interpreted in terms of a change in the screening properties of the grain charge. At low dust density, the grain charge is screened due to electrons and ions. However, at high dust density, the screening of the grain charge due to other grains also becomes important. This leads to a reduction of the phase-velocity, which in turn is shown to make the plasma more unstable at high dust density. In this regime the role of the ion acoustic mode is replaced by the charging mode. The relevance of these results to earlier theoretical studies and experimental results are discussed
Resonant MHD modes with toroidal coupling
International Nuclear Information System (INIS)
Connor, J.W.; Hastie, R.J.; Taylor, J.B.
1990-07-01
This is part 2 of a study of resonant perturbations, such as resistive tearing and ballooning modes, in a torus. These are described by marginal ideal mhd equations in the regions between resonant surfaces; matching across these surfaces provides the dispersion relation. In part 1 we described how all the necessary information from the ideal mhd calculations could be represented by a so-called E-matrix. We also described the calculation of this E-matrix for tearing modes (even parity in perturbed magnetic field) in a large aspect ratio torus. There the toroidal modes comprise coupled cylinder tearing modes and the E-matrix is a generalization of the familiar Δ' quantity in a cylinder. In the present paper we discuss resistive ballooning, or twisting-modes, which have odd-parity in perturbed magnetic field. We show that, unlike the tearing modes, these odd-parity modes are instrinsically toroidal and are not directly related to the odd-parity modes in a cylinder. This is evident from the analysis of the high-n limit in ballooning-space, where a transition from a stable Δ' to an unstable Δ' occurs for the twisting mode when the ballooning effect exceeds the interchange effect, which can occur even at large aspect ratio (as in a tokamak). Analysis of the high-n limit in coordinate space, rather than ballooning space, clarifies this singular behaviour and indicates how one may define twisting-mode Δ'. It also yields a prescription for treating low-n twisting modes and a method for calculating an E-matrix for resistive ballooning modes in a large aspect ratio tokamak. The elements of this matrix are given in terms of cylindrical tearing mode solutions
Nonlinear dynamics of a driven mode near marginal stability
International Nuclear Information System (INIS)
Berk, H.L.; Breizman, B.N.; Pekker, M.
1995-09-01
The nonlinear dynamics of a linearly unstable mode in a driven kinetic system is investigated to determine scaling of the saturated fields near the instability threshold. To leading order, this problem reduces to solving an integral equation with a temporally nonlocal cubic term. This equation can exhibit a self-similar solution that blows up in a finite time. When the blow-up occurs, higher nonlinearities become important and the mode saturates due to plateau formation arising from particle trapping in the wave. Otherwise, the simplified equation gives a regular solution that leads to a different saturation scaling reflecting the closeness to the instability threshold
Quasinormal modes of Schwarzschild black holes: Defined and calculated via Laplace transformation
International Nuclear Information System (INIS)
Nollert, H.; Schmidt, B.G.
1992-01-01
Quasinormal modes play a prominent role in the literature when dealing with the propagation of linearized perturbations of the Schwarzschild geometry. We show that space-time properties of the solutions of the perturbation equation imply the existence of a unique Green's function of the Laplace-transformed wave equation. This Green's function may be constructed from solutions of the homogeneous time-independent equation, which are uniquely characterized by the boundary conditions they satisfy. These boundary conditions are identified as the boundary conditions usually imposed for quasinormal-mode solutions. It turns out that solutions of the homogeneous equation exist which satisfy these boundary conditions at the horizon and at spatial infinity simultaneously, leading to poles of the Green's function. We therefore propose to define quasinormal-mode frequencies as the poles of the Green's function for the Laplace-transformed equation. On the basis of this definition a new technique for the numerical calculation of quasinormal frequencies is developed. The results agree with computations of Leaver, but not with more recent results obtained by Guinn, Will, Kojima, and Schutz
Energy Technology Data Exchange (ETDEWEB)
Koshelev, A. S., E-mail: alexsander.coshelev@yandex.ru; Arapov, A. V.; Ovchinnikov, M. A. [Russian Federal Nuclear Center–All-Russian Research Institute of Experimental Physics (Russian Federation)
2016-12-15
The file-evaluation results of a reactimeter based on the inverse solution to the kinetics equation (ISKE) are presented, which were obtained using an operating hardware-measuring complex with a KNK-4 neutron detector working in the current mode. The processing of power-recording files of the BR-1M, BR-K1, and VIR-2M reactors of the Russian Federal Nuclear Center—All-Russian Research Institute of Experimental Physics, which was performed with the use of Excel simulation of the ISKE formalism, demonstrated the feasibility of implementation of the reactivity monitoring (during the operation of these reactors at stationary power) beginning from the level of ~5 × 10{sup –4}β{sub eff}.
Characterizations of sugar ball in solution by SANS and NSE
International Nuclear Information System (INIS)
Funayama, Katsuya; Imae, Toyoko; Aoi, Keigo; Tsutsumiuchi, Kaname; Okada, Masahiko; Seto, Hideki; Nagao, Michihiro
2001-01-01
Overall static and dynamic characterizations of the dendrimer are expected to be modified through changing the internal and terminal chemical structures of the dendrimer. In the present study, the aqueous solutions of the fifth generation glycopeptide-type sugar ball at 1 and 10 wt% dendrimer concentrations, which show different small-angle neutron scattering profiles, were measured by neutron spin echo. The diffusion behaviors were found to depend on dendrimer concentration, as well as for the solutions of fifth generation poly (amido amine) dendrimer with hydroxyl terminals. A slow relaxation mode was obtained at high concentration but the fast and slow modes were at low concentration. It was concluded that the slow mode is translational diffusion of dendrimer and the fast one due to segment motion in dendrimer. Since the fast mode was found for both dendrimer solutions, that will be specific dynamics originated by amido-amine unit in dendrimer, which is common in both dendrimers. (author)
Interpretation and further properties of general classical CPsup(n-1) solutions
International Nuclear Information System (INIS)
Din, A.M.
1980-11-01
We present arguments suggesting that non-(anti)selfdual classical solutions to the equations of motion of the euclidean CPsup(n-1) model can be interpreted as unstable non-interacting mixtures of instantons and anti-instantons. Fermionic modes in the background of these solutions are discussed. We determine the modes explicitly for the case of an embedded O(3) solution and point out that they give rise to a non-trivial illustration of the Atiyah-Singer index theorem
Energy Technology Data Exchange (ETDEWEB)
Ibrahim, H.; Dimitrova, M. [TechnoCentre eolien Gaspesie-les Iles, Gaspe, PQ (Canada); Ilinca, A. [Quebec Univ., Rimouski, PQ (Canada); Perron, J. [Quebec Univ., Chicoutimi, PQ (Canada)
2010-07-01
This poster reported on a study that examined the feasibility of using a hybrid wind-diesel-compressed air system to produce electricity at remote telecommunication stations. Low and high penetration wind-diesel hybrid systems were studied in order to reduce the diesel consumption. The use of a high penetration wind-diesel system together with compressed air energy storage (CAES) was shown to be a viable alternative to improve the overall percentage of renewable energy and reduce the cost of electricity in remote areas where a good wind resource is available. Different technical solutions for the CAES system were compared. refs., figs.
Operating modes of superconducting tunnel junction device
Energy Technology Data Exchange (ETDEWEB)
Maehata, Keisuke [Kyushu Univ., Fukuoka (Japan). Faculty of Engineering
1998-07-01
In the Electrotechnical Laboratory, an Nb type superconducting tunnel junction (STJ) device with 200 x 200 sq. micron in area and super high quality was manufactured. By using 55-fe source, response of this large area STJ to X-ray was measured. In this measurement, two action modes with different output wave height from front amplifier were observed. Then, in this study, current-voltage feature of the element in each action mode was analyzed to elucidate a mechanism to form such two action modes. The feature was analyzed by using first order approximate solution on cavity resonance mode of Sine-Gordon equation. From the analytical results, it could be supposed that direction and magnitude of effective magnetic field penetrating into jointed area changed by an induction current effect owing to impressing speed of the magnetic field, which brings two different current-voltage features to make possible to observe two action modes with different pulse wave height. (G.K.)
Quasiadiabatic modes from viscous inhomogeneities
Giovannini, Massimo
2016-04-20
The viscous inhomogeneities of a relativistic plasma determine a further class of entropic modes whose amplitude must be sufficiently small since curvature perturbations are observed to be predominantly adiabatic and Gaussian over large scales. When the viscous coefficients only depend on the energy density of the fluid the corresponding curvature fluctuations are shown to be almost adiabatic. After addressing the problem in a gauge-invariant perturbative expansion, the same analysis is repeated at a non-perturbative level by investigating the nonlinear curvature inhomogeneities induced by the spatial variation of the viscous coefficients. It is demonstrated that the quasiadiabatic modes are suppressed in comparison with a bona fide adiabatic solution. Because of its anomalously large tensor to scalar ratio the quasiadiabatic mode cannot be a substitute for the conventional adiabatic paradigm so that, ultimately, the present findings seems to exclude the possibility of a successful accelerated dynamics solely...
Ion temperature gradient mode driven solitons and shocks
Zakir, U.; Adnan, Muhammad; Haque, Q.; Qamar, Anisa; Mirza, Arshad M.
2016-04-01
Ion temperature gradient (ITG) driven solitons and shocks are studied in a plasma having gradients in the equilibrium number density and equilibrium ion temperature. In the linear regime, it is found that the ion temperature and the ratio of the gradient scale lengths, ηi=Ln/LT , affect both the real frequency and the growth rate of the ITG driven wave instability. In the nonlinear regime, for the first time we derive a Korteweg de Vries-type equation for the ITG mode, which admits solitary wave solution. It is found that the ITG mode supports only compressive solitons. Further, it is noticed that the soliton amplitude and width are sensitive to the parameter ηi=Ln/LT . Second, in the presence of dissipation in the system, we obtain a Burger type equation, which admits the shock wave solution. This work may be useful to understand the low frequency electrostatic modes in inhomogeneous electron-ion plasma having density and ion temperature gradients. For illustration, the model has been applied to tokamak plasma.
Laser modes as an eigenfunction of an operator equation
International Nuclear Information System (INIS)
Ripper, J.E.; Campos, M.D.; Pudensi, M.A.A.
A new method is proposed of arriving to an approximate solution into mode problems which cannot be treated by the traditional methods. Basically the idea is to treat the laser mode as an eigenfunction of an operator equation so that the mathematical methods developed to treat the wave equations in quantum mechanics can be used as tools to solve the equation. (L.C.) [pt
Electron eigen-oscillations and ballistic modes of a stable plasma
International Nuclear Information System (INIS)
Jungwirth, K.
1976-01-01
The relation between plasma responses to singular and regular initial perturbations is established. Time scaling is introduced to separate time intervals for which eigen-oscillations (Landau solution) are dominant from such where ballistic modes prevail. The enhanced role is demonstrated of the ballistic modes for an initially perturbed field-free plasma including the phenomenon of plasma wave echoes. (author)
Destabilization of low-n peeling modes by trapped energetic particles
Energy Technology Data Exchange (ETDEWEB)
Hao, G. Z.; Wang, A. K.; Mou, Z. Z.; Qiu, X. M. [Southwestern Institute of Physics, PO Box 432, Chengdu 610041 (China); Liu, Y. Q. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Matsunaga, G. [Japan Atomic Energy Agency, 801-1, Mukouyama, Naka, Ibaraki 311-0193 (Japan); Okabayashi, M. [Princeton Plasma Physics Laboratory, PO Box 451, Princeton, New Jersey 08543-0451 (United States)
2013-06-15
The kinetic effect of trapped energetic particles (EPs), arising from perpendicular neutral beam injection, on the stable low-n peeling modes in tokamak plasmas is investigated, through numerical solution of the mode's dispersion relation derived from an energy principle. A resistive-wall peeling mode with m/n=6/1, with m and n being the poloidal and toroidal mode numbers, respectively, is destabilized by trapped EPs as the EPs' pressure exceeds a critical value β{sub c}{sup *}, which is sensitive to the pitch angle of trapped EPs. The dependence of β{sub c}{sup *} on the particle pitch angle is eventually determined by the bounce average of the mode eigenfunction. Peeling modes with higher m and n numbers can also be destabilized by trapped EPs. Depending on the wall distance, either a resistive-wall peeling mode or an ideal-kink peeling mode can be destabilized by EPs.
Compressed air energy storage technology program. Annual report for 1979
Energy Technology Data Exchange (ETDEWEB)
Loscutoff, W.V.
1980-06-01
The objectives of the Compressed Air Energy Storage (CAES) program are to establish stability criteria for large underground reservoirs in salt domes, hard rock, and porous rock used for air storage in utility applications, and to develop second-generation CAES technologies that have minimal or no dependence on petroleum fuels. During the year reported reports have been issued on field studies on CAES on aquifers and in salt, stability, and design criteria for CAES and for pumped hydro-storage caverns, laboratory studies of CAES in porous rock reservoris have continued. Research has continued on combined CAES/Thermal Energy Storage, CAES/Solar systems, coal-fired fluidized bed combustors for CAES, and two-reservoir advanced CAES concepts. (LCL)
Multiresonance modes in sine–Gordon brane models
Energy Technology Data Exchange (ETDEWEB)
Cruz, W.T., E-mail: wilamicruz@gmail.com [Instituto Federal de Educação, Ciência e Tecnologia do Ceará (IFCE), Campus Juazeiro do Norte, 63040-540 Juazeiro do Norte-Ceará (Brazil); Maluf, R.V., E-mail: r.v.maluf@fisica.ufc.br [Universidade Federal do Ceará (UFC), Departamento de Física, Campus do Pici, Fortaleza - CE, C.P. 6030, 60455-760 (Brazil); Dantas, D.M., E-mail: davi@fisica.ufc.br [Universidade Federal do Ceará (UFC), Departamento de Física, Campus do Pici, Fortaleza - CE, C.P. 6030, 60455-760 (Brazil); Almeida, C.A.S., E-mail: carlos@fisica.ufc.br [Universidade Federal do Ceará (UFC), Departamento de Física, Campus do Pici, Fortaleza - CE, C.P. 6030, 60455-760 (Brazil)
2016-12-15
In this work, we study the localization of the vector gauge field in two five-dimensional braneworlds generated by scalar fields coupled to gravity. The sine–Gordon like potentials are employed to produce different thick brane setups. A zero mode localized is obtained, and we show the existence of reverberations with the wave solutions indicating a quasi-localized massive mode. More interesting results are achieved when we propose a double sine–Gordon potential to the scalar field. The resulting thick brane shows a more detailed topology with the presence of an internal structure composed by two kinks. The massive spectrum of the gauge field is revalued on this scenario revealing the existence of various resonant modes. Furthermore, we compute the corrections to Coulomb law coming from these massive KK vector modes in these thick scenarios, which is concluded that the dilaton parameter regulates these corrections.
Multiresonance modes in sine–Gordon brane models
International Nuclear Information System (INIS)
Cruz, W.T.; Maluf, R.V.; Dantas, D.M.; Almeida, C.A.S.
2016-01-01
In this work, we study the localization of the vector gauge field in two five-dimensional braneworlds generated by scalar fields coupled to gravity. The sine–Gordon like potentials are employed to produce different thick brane setups. A zero mode localized is obtained, and we show the existence of reverberations with the wave solutions indicating a quasi-localized massive mode. More interesting results are achieved when we propose a double sine–Gordon potential to the scalar field. The resulting thick brane shows a more detailed topology with the presence of an internal structure composed by two kinks. The massive spectrum of the gauge field is revalued on this scenario revealing the existence of various resonant modes. Furthermore, we compute the corrections to Coulomb law coming from these massive KK vector modes in these thick scenarios, which is concluded that the dilaton parameter regulates these corrections.
Robust output LQ optimal control via integral sliding modes
Fridman, Leonid; Bejarano, Francisco Javier
2014-01-01
Featuring original research from well-known experts in the field of sliding mode control, this monograph presents new design schemes for implementing LQ control solutions in situations where the output system is the only information provided about the state of the plant. This new design works under the restrictions of matched disturbances without losing its desirable features. On the cutting-edge of optimal control research, Robust Output LQ Optimal Control via Integral Sliding Modes is an excellent resource for both graduate students and professionals involved in linear systems, optimal control, observation of systems with unknown inputs, and automatization. In the theory of optimal control, the linear quadratic (LQ) optimal problem plays an important role due to its physical meaning, and its solution is easily given by an algebraic Riccati equation. This solution turns out to be restrictive, however, because of two assumptions: the system must be free from disturbances and the entire state vector must be kn...
Examination of the 'web mode effect'
DEFF Research Database (Denmark)
Clement, Sanne Lund; Shamshiri-Petersen, Ditte
Declining response rates is one of the most significant challenges for survey based research today. Seen in isolation, traditional interviewer based data collection methods are still the most effective but also the most expensive, especially the greater difficulty in gaining responses taken...... into account. As a solution, mixed-mode designs have been employed as a way to achieve higher response rates, while keeping the overall costs low. In particular, the use of web based surveys has expanded considerably during the last few years, both as a single data collection method and as a component in mixed...... with telephone surveys, not enabling determination of a “web mode effect”. In this case, differences might as well be due to differences between self-administered and interviewer-administered collection methods. Other parts of literature on mixed-mode design including a web option are using stratified sampling...
International Nuclear Information System (INIS)
Dechoum, K.; Hahn, M. D.; Khoury, A. Z.; Vallejos, R. O.
2010-01-01
We derive the steady-state solution of the Fokker-Planck equation that describes the dynamics of the nondegenerate optical parametric oscillator in the truncated Wigner representation of the density operator. We assume that the pump mode is strongly damped, which permits its adiabatic elimination. When the elimination is correctly executed, the resulting stochastic equations contain multiplicative noise terms and do not admit a potential solution. However, we develop a heuristic scheme leading to a satisfactory steady-state solution. This provides a clear view of the intracavity two-mode entangled state valid in all operating regimes of the optical parametric oscillator. A non-Gaussian distribution is obtained for the above threshold solution.
On the completeness of the natural modes for quantum mechanical potential scattering
Hoenders, B.J.
1979-01-01
The set of natural modes, associated with quantum mechanical scattering from a central potential of finite-range is shown to be complete. The natural modes satisfy a non-Hermitian homogeneous integral equation, or alternatively, are solutions of the time independent Schrödinger equation subject to a
Benbouzid, Mohamed; Beltran, Brice; Amirat, Yassine; Yao, Gang; Han, Jingang; Mangel, Hervé
2014-05-01
This paper deals with the fault ride-through capability assessment of a doubly fed induction generator-based wind turbine using a high-order sliding mode control. Indeed, it has been recently suggested that sliding mode control is a solution of choice to the fault ride-through problem. In this context, this paper proposes a second-order sliding mode as an improved solution that handle the classical sliding mode chattering problem. Indeed, the main and attractive features of high-order sliding modes are robustness against external disturbances, the grids faults in particular, and chattering-free behavior (no extra mechanical stress on the wind turbine drive train). Simulations using the NREL FAST code on a 1.5-MW wind turbine are carried out to evaluate ride-through performance of the proposed high-order sliding mode control strategy in case of grid frequency variations and unbalanced voltage sags. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.
Proceedings of the 4th workshop on WENDELSTEIN 7-X
International Nuclear Information System (INIS)
Junker, J.
1991-12-01
The 4th Workshop on WENDELSTEIN 7-x (28.-31.10.1991) treated the following topics: Coil System (optimization; ripple transport; magnetic fields, forces, stresses; analytic stellarator fields) - equilibrium and stability (computations; equilibrium with dissipation; global MHD stability; resistive ballooning modes) - transport and neutral gas (Pfirsch-Schlueter currents and anomalous transport; general solution of the ripple-averaged equation; the EIRENE neutral gas transport codes; application of DEGAS; CX-losses at NBI) - plasma parameters (alpha particle confinement in stellarators; the radical electric field in W 7) - divertor (structure of the magnetic field line diversion in Helias configurations; divertor studies for W 7; sweep coil system; the island divertor; one-dimensional fluid model and investigation of the plasma boundary layer) - engineering (W 7 status of planning; CAD/CAE applications for W 7; structural analysis of the coil system) - reactor (the Helias reactor) - concluding discussion. (AH)
Inertial and viscous effects in the non linear growth of the tearing mode
International Nuclear Information System (INIS)
Edery, D.; Frey, M.; Tagger, M.; Soule, J.L.; Pellat, R.; Bussac, M.N.; Somon, J.P.
1982-08-01
The non linear self similar Tearing mode solution of Rutherford is revisited. We compute explicitly the stream function for the plasma flow including inertia, convection and viscosity. In all cases, Rutherford's solution is asymptotically valid
OPERATION MODES AND CHARACTERISTICS OF PLASMA DIPOLE ANTENNA
Directory of Open Access Journals (Sweden)
Nikolay Nikolaevich Bogachev
2014-02-01
Full Text Available Existence modes of surface electromagnetic wave on a plasma cylinder, operating modes and characteristics of the plasma antenna were studied in this paper. Solutions of the dispersion equation of surface wave were obtained for a plasma cylinder with finite radius for different plasma density values. Operation modes of the plasma asymmetric dipole antenna with finite length and radius were researched by numerical simulation. The electric field distributions of the plasma antenna in near antenna field and the radiation pattern were obtained. These characteristics were compared to characteristics of the similar metal antenna. Numerical models verification was carried out by comparing of the counted and measured metal antenna radiation patterns.
Resistive internal kink modes in a tokamak with high-pressure plasma
International Nuclear Information System (INIS)
Kuvshinov, B.N.; Mikhajlovskij, A.B.; Tatarinov, E.G.
1988-01-01
Theory of resistive internal kink modes in a tokamak with high-pressure plasma is developed. Equation for Fourie-image of disturbed displacment in a resistive layer ie derived with regard to effects of the fourth order by plasma pressure within the framework of single-liquid approach. In its structure this equation coincides with a similar equation for resistive balloon modes and has an exact solution expressed by degenerated hypergeometric function. A general dispersion equation for resistive kink modes is derived with regard to the effects indicated. It is shown that plasma pressure finiteness leads to the reduction of reconnection and tyring-mode increments
Performance analysis and experimental study of heat-source tower solution regeneration
International Nuclear Information System (INIS)
Liang, Caihua; Wen, Xiantai; Liu, Chengxing; Zhang, Xiaosong
2014-01-01
Highlights: • Theoretical analysis is performed on the characteristics of heat-source tower. • Experimental study is performed on various rules of the solution regeneration rate. • The characteristics of solution regeneration vary widely with different demands. • Results are useful for optimizing the process of solution regeneration. - Abstract: By analyzing similarities and difference between the solution regeneration of a heat-source tower and desiccant solution regeneration, this paper points out that solution regeneration of a heat-source tower has the characteristics of small demands and that a regeneration rate is susceptible to outdoor ambient environments. A theoretical analysis is performed on the characteristics of a heat-source tower solution in different outdoor environments and different regeneration modes, and an experimental study is performed on variation rules of the solution regeneration rate of a cross-flow heat-source tower under different inlet parameters and operating parameters. The experimental results show that: in the operating regeneration mode, as the air volume was increased from 123 m 3 h −1 to 550 m 3 h −1 , the system heat transfer amount increased from 0.42 kW to 0.78 kW, and the regeneration rate increased from 0.03 g s −1 to 0.19 g s −1 . Increasing the solution flow may increase the system heat transfer amount; however, the regeneration rate decreased to a certain extent. In the regeneration mode when the system is idle, as the air volume was increased from 136 m 3 h −1 to 541 m 3 h −1 , the regeneration rate increased from 0.03 g s −1 to 0.1 g s −1 . The regeneration rate almost remained unchanged around 0.07 g s −1 as the solution flow is increased. In the regeneration mode with auxiliary heat when the system is idle, increasing the air volume and increasing the solution flow required more auxiliary heat, thereby improving the solution regeneration rate. As the auxiliary heat was increased from 0.33 k
International Nuclear Information System (INIS)
Bagdanavicius, Audrius; Jenkins, Nick
2014-01-01
Highlights: • CAES and CAES with thermal storage systems were investigated. • The potential for using heat generated during the compression stage was analysed. • CAES-TS has the potential to be used both as energy storage and heat source. • CAES-TS could be a useful tool for balancing overall energy demand and supply. - Abstract: The potential for using heat generated during the compression stage of a Compressed Air Energy Storage system was investigated using exergy and exergoeconomic analysis. Two Compressed Air Energy Storage systems were analysed: Compressed Air Energy Storage (CAES) and Compressed Air Energy Storage combined with Thermal Storage (CAES-TS) connected to a district heating network. The maximum output of the CAES was 100 MWe and the output of the CAES-TS was 100 MWe and 105 MWth. The study shows that 308 GW h/year of electricity and 466 GW h/year of fuel are used to generate 375 GW h/year of electricity. During the compression of air 289 GW h/year of heat is generated, which is wasted in the CAES and used for district heating in the CAES-TS system. Energy efficiency of the CAES system was around 48% and the efficiency of CAES-TS was 86%. Exergoeconomic analysis shows that the exergy cost of electricity generated in the CAES was 13.89 ¢/kW h, and the exergy cost of electricity generated in the CAES-TS was 11.20 ¢/kW h. The exergy cost of heat was 22.24 ¢/kW h in the CAES-TS system. The study shows that CAES-TS has the potential to be used both as energy storage and heat source and could be a useful tool for balancing overall energy demand and supply
Resistive effects on line-tied magnetohydrodynamic modes in cylindrical geometry
International Nuclear Information System (INIS)
Delzanno, Gian Luca; Evstatiev, E. G.; Finn, John M.
2007-01-01
An investigation of the effect of resistivity on the linear stability of line-tied magnetohydrodynamic (MHD) modes is presented in cylindrical geometry, based on the method recently developed in the paper by Evstatiev et al. [Phys. Plasmas 13, 072902 (2006)]. The method uses an expansion of the full solution of the problem in one-dimensional radial eigenfunctions. This method is applied to study sausage modes (m=0, m being the poloidal wavenumber), kink modes (m=1), and m=2 modes. All these modes can be resistively unstable. It is found that m≠0 modes can be unstable below the ideal MHD threshold due to resistive diffusion of the field lines, with growth rates proportional to resistivity. For these resistive modes, there is no indication of tearing, i.e., current sheets or boundary layers due to ideal MHD singularities. That is, resistivity acts globally on the whole plasma column and not in layers. Modes with m=0, on the other hand, can exist as tearing modes if the equilibrium axial magnetic field reverses sign within the plasma
Curvature effects in the nonlinear growth of the cylindrical tearing mode
International Nuclear Information System (INIS)
Somon, J. P.
1984-01-01
The full set of the usual resistive massless equations is used to investigate the nonlinear growth of the helical perturbation to a cylindrical equilibrium with tokamak ordering. There is a curvature dependant critical magnetic island width xsub(T)sup(*) α set containing D/Δ' above which the Rutherford solution is recovered for the tearing mode as well as for the linear slow interchange modes with Δ' > 0. Non linearity stabilizes at this critical width the linearly unstable slow interchange modes with Δ' > 0
Numerical Solution of the Electron Transport Equation in the Upper Atmosphere
Energy Technology Data Exchange (ETDEWEB)
Woods, Mark Christopher [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Holmes, Mark [Rensselaer Polytechnic Inst., Troy, NY (United States); Sailor, William C [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2017-07-01
A new approach for solving the electron transport equation in the upper atmosphere is derived. The problem is a very stiff boundary value problem, and to obtain an accurate numerical solution, matrix factorizations are used to decouple the fast and slow modes. A stable finite difference method is applied to each mode. This solver is applied to a simplifieed problem for which an exact solution exists using various versions of the boundary conditions that might arise in a natural auroral display. The numerical and exact solutions are found to agree with each other to at least two significant digits.
Directory of Open Access Journals (Sweden)
Hossein Safaei
2017-07-01
Full Text Available We present analyses of three families of compressed air energy storage (CAES systems: conventional CAES, in which the heat released during air compression is not stored and natural gas is combusted to provide heat during discharge; adiabatic CAES, in which the compression heat is stored; and CAES in which the compression heat is used to assist water electrolysis for hydrogen storage. The latter two methods involve no fossil fuel combustion. We modeled both a low-temperature and a high-temperature electrolysis process for hydrogen production. Adiabatic CAES (A-CAES with physical storage of heat is the most efficient option with an exergy efficiency of 69.5% for energy storage. The exergy efficiency of the conventional CAES system is estimated to be 54.3%. Both high-temperature and low-temperature electrolysis CAES systems result in similar exergy efficiencies (35.6% and 34.2%, partly due to low efficiency of the electrolyzer cell. CAES with high-temperature electrolysis has the highest energy storage density (7.9 kWh per m3 of air storage volume, followed by A-CAES (5.2 kWh/m3. Conventional CAES and CAES with low-temperature electrolysis have similar energy densities of 3.1 kWh/m3.
Theory of electrostatic fluid modes in a cold spheroidal non-neutral plasma
International Nuclear Information System (INIS)
Dubin, D.H.E.
1991-01-01
The normal modes of a magnetized spheroidally shaped pure ion plasma have recently been measured. Here the theory of these modes is presented. Although one might expect that a numerical solution is required (because the plasma dielectric is anisotropic and the plasma is inhomogeneous), the problem is actually separable in an unusual coordinate system. The result is a simple electrostatic fluid dispersion relation for modes in a cloud of any spheroidal shape
Stability of plane wave solutions of the two-space-dimensional nonlinear Schroedinger equation
International Nuclear Information System (INIS)
Martin, D.U.; Yuen, H.C.; Saffman, P.G.
1980-01-01
The stability of plane, periodic solutions of the two-dimensional nonlinear Schroedinger equation to infinitesimal, two-dimensional perturbation has been calculated and verified numerically. For standing wave disturbances, instability is found for both odd and even modes; as the period of the unperturbed solution increases, the instability associated with the odd modes remains but that associated with the even mode disappears, which is consistent with the results of Zakharov and Rubenchik, Saffman and Yuen and Ablowitz and Segur on the stability of solitons. In addition, we have identified travelling wave instabilities for the even mode perturbations which are absent in the long-wave limit. Extrapolation to the case of an unperturbed solution with infinite period suggests that these instabilities may also be present for the soliton. In other words, the soliton is unstable to odd, standing-wave perturbations, and very likely also to even, travelling-wave perturbations. (orig.)
Zero modes in discretized light-front quantization
International Nuclear Information System (INIS)
Martinovic, E.
1997-01-01
The current understanding of the role of bosonic zero modes in field-theoretical models quantized at the equal light-front time is reviewed. After a brief discussion of the main features of the light-front field theories - in particular the simplicity of the physical vacuum - the light-front canonical formalism for the quantum electrodynamics and the Yukawa model is sketched. The zero mode of Maskawa and Yamawaki is reviewed. Reasons for the appearance of the constrained and/or dynamical zero modes are explained along with the subtleties of the gauge fixing in presence of boundary conditions. Perturbative treatment of the corresponding constraint equations in the Yukawa model and quantum electrodynamics (3+1) is outlined. The next topic is the manifestation of the symmetry breaking in the light-front field theory. A pattern of multiple solutions to the zero-mode constraint equations replacing physical picture of multiple vacua of the conventionally quantized field theories is illustrated on an example of 2-dimensional theory. The importance of a (regularized) constrained zero mode of the pion field for the consistency of the Nambu-Goldstone phase of the discretized light-front linear a/model is demonstrated. Finally, a non-trivial physical vacuum based on the dynamical zero mode is constructed for the two-dimensional light-front quantum electrodynamics. (authors)
Velocity fields and transition densities in nuclear collective modes
Energy Technology Data Exchange (ETDEWEB)
Stringari, S [Dipartimento di Matematica e Fisica, Libera Universita di Trento, Italy
1979-08-13
The shape of the deformations occurring in nuclear collective modes is investigated by means of a microscopic approach. Analytical solutions of the equations of motion are obtained by using simplified nuclear potentials. It is found that the structure of the velocity field and of the transition density of low-lying modes is considerably different from the predictions of irrotational hydrodynamic models. The low-lying octupole state is studied in particular detail by using the Skyrme force.
Propagation of Finite Amplitude Sound in Multiple Waveguide Modes.
van Doren, Thomas Walter
1993-01-01
This dissertation describes a theoretical and experimental investigation of the propagation of finite amplitude sound in multiple waveguide modes. Quasilinear analytical solutions of the full second order nonlinear wave equation, the Westervelt equation, and the KZK parabolic wave equation are obtained for the fundamental and second harmonic sound fields in a rectangular rigid-wall waveguide. It is shown that the Westervelt equation is an acceptable approximation of the full nonlinear wave equation for describing guided sound waves of finite amplitude. A system of first order equations based on both a modal and harmonic expansion of the Westervelt equation is developed for waveguides with locally reactive wall impedances. Fully nonlinear numerical solutions of the system of coupled equations are presented for waveguides formed by two parallel planes which are either both rigid, or one rigid and one pressure release. These numerical solutions are compared to finite -difference solutions of the KZK equation, and it is shown that solutions of the KZK equation are valid only at frequencies which are high compared to the cutoff frequencies of the most important modes of propagation (i.e., for which sound propagates at small grazing angles). Numerical solutions of both the Westervelt and KZK equations are compared to experiments performed in an air-filled, rigid-wall, rectangular waveguide. Solutions of the Westervelt equation are in good agreement with experiment for low source frequencies, at which sound propagates at large grazing angles, whereas solutions of the KZK equation are not valid for these cases. At higher frequencies, at which sound propagates at small grazing angles, agreement between numerical solutions of the Westervelt and KZK equations and experiment is only fair, because of problems in specifying the experimental source condition with sufficient accuracy.
Finite Larmor radius stabilization of ballooning modes in tokamaks
International Nuclear Information System (INIS)
Tsang, K.T.
1980-07-01
A ballooning mode equation that includes full finite Larmor radius effects has been derived from the Vlasov equation for a circular tokamak equilibrium. Numerical solution of this equation shows that finite Larmor radius effects are stabilizing
Coupled-Mode Theory for Complex-Index, Corrugated Multilayer Stacks
DEFF Research Database (Denmark)
Lüder, Hannes; Gerken, Martina; Adam, Jost
, and by choosing a bi-orthogonal basis, obtained by solving the corresponding adjoint problem. With the once found modal solutions of the unperturbed waveguide, we can calculate the coupling coefficients, which describe the mode coupling caused by the introduced periodic corrugation. [1] C. Kluge et al., Opt......We present a coupled-mode theory (CMT) approach for modelling the modal behaviour of multi- layer thinfilm devices with complex material parameters and periodic corrugations. Our method provides fast computation and extended physical insight as compared to standard numerical methods...... to be non-Hermitian, introducing two major consequences. First, the eigenvalues (i. e. the mode neff) have to be found in the complex plane (Fig. 2). Second, the classical mode orthogonality is no longer valid. We address both challenges by a combination of three complex-root solving algorithms...
Simulation of operation modes of isochronous cyclotron by a new interactive method
International Nuclear Information System (INIS)
Taraszkiewicz, R.; Talach, M.; Sulikowski, J.; Doruch, H.; Norys, T.; Sroka, A.; Kiyan, I.N.; )
2007-01-01
Operation mode simulation methods are based on selection of trim coil currents in the isochronous cyclotron for formation of the required magnetic field at a certain level of the main coil current. The traditional current selection method is based on finding a solution for all trim coils simultaneously. After setting the calculated operation mode, it is usually necessary to perform a control measurement of the magnetic field map and to repeat the calculation for a more accurate solution. The new current selection method is based on successively finding solutions for each particular trim coil. The trim coils are taken one by one in reverse order from the edge to the center of the isochronous cyclotron. The new operation mode simulation method is based on the new current selection method. The new method, as against the traditional one, includes iterative calculation of the kinetic energy at the extraction radius. A series of experiments on proton beam formation within the range of working acceleration radii at extraction energies from 32 to 59 MeV, which were carried out at the AIC144 multipurpose isochronous cyclotron (designed mainly for the eye melanoma treatment and production of radioisotopes) at the INP PAS (Cracow), showed that the new method makes unnecessary any control measurements of magnetic fields for getting the desired operation mode, which indicates a high accuracy of the calculation. (authors)
Method of adiabatic modes in studying problems of smoothly irregular open waveguide structures
Energy Technology Data Exchange (ETDEWEB)
Sevastianov, L. A., E-mail: sevast@sci.pfu.edu.ru [Peoples' Friendship University of Russia (Russian Federation); Egorov, A. A. [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation); Sevastyanov, A. L. [Peoples' Friendship University of Russia (Russian Federation)
2013-02-15
Basic steps in developing an original method of adiabatic modes that makes it possible to solve the direct and inverse problems of simulating and designing three-dimensional multilayered smoothly irregular open waveguide structures are described. A new element in the method is that an approximate solution of Maxwell's equations is made to obey 'inclined' boundary conditions at the interfaces between themedia being considered. These boundary conditions take into account the obliqueness of planes tangent to nonplanar boundaries between the media and lead to new equations for coupled vector quasiwaveguide hybrid adiabatic modes. Solutions of these equations describe the phenomenon of 'entanglement' of two linear polarizations of an irregular multilayered waveguide, the appearance of a new mode in an entangled state, and the effect of rotation of the polarization plane of quasiwaveguide modes. The efficiency of the method is demonstrated by considering the example of numerically simulating a thin-film generalized waveguide Lueneburg lens.
Method of adiabatic modes in studying problems of smoothly irregular open waveguide structures
International Nuclear Information System (INIS)
Sevastianov, L. A.; Egorov, A. A.; Sevastyanov, A. L.
2013-01-01
Basic steps in developing an original method of adiabatic modes that makes it possible to solve the direct and inverse problems of simulating and designing three-dimensional multilayered smoothly irregular open waveguide structures are described. A new element in the method is that an approximate solution of Maxwell’s equations is made to obey “inclined” boundary conditions at the interfaces between themedia being considered. These boundary conditions take into account the obliqueness of planes tangent to nonplanar boundaries between the media and lead to new equations for coupled vector quasiwaveguide hybrid adiabatic modes. Solutions of these equations describe the phenomenon of “entanglement” of two linear polarizations of an irregular multilayered waveguide, the appearance of a new mode in an entangled state, and the effect of rotation of the polarization plane of quasiwaveguide modes. The efficiency of the method is demonstrated by considering the example of numerically simulating a thin-film generalized waveguide Lüneburg lens.
Effect of sheared flows on neoclassical tearing modes
Energy Technology Data Exchange (ETDEWEB)
Sen, A [Institute for Plasma Research, Bhat, Gandhinagar (India); Chandra, D; Kaw, P [Institute for Plasma Research, Bhat, Gandhinagar (India); Bora, M P [Physics Dept., Gauhati University, Guwahati (India); Kruger, S [Tech-X, Boulder, CO (United States); Ramos, J [Plasma Science and Fusion Center, MIT, Cambridge, MA (United States)
2005-01-01
The influence of toroidal sheared equilibrium flows on the nonlinear evolution of classical and neoclassical tearing modes (NTMs) is studied through numerical solutions of a set of reduced generalized MHD equations that include viscous force effects based on neoclassical closures. In general, differential flow is found to have a strong stabilizing influence leading to lower saturated island widths for the classical (m/n = 2/1) mode and reduced growth rates for the (m/n = 3/1) neoclassical mode. Velocity shear on the other hand is seen to make a destabilizing contribution. An analytic model calculation, consisting of a generalized Rutherford island evolution equation that includes shear flow effects is also presented and the numerical results are discussed in the context of this model. (author)
Dynamics of coupled mode solitons in bursting neural networks
Nfor, N. Oma; Ghomsi, P. Guemkam; Moukam Kakmeni, F. M.
2018-02-01
Using an electrically coupled chain of Hindmarsh-Rose neural models, we analytically derived the nonlinearly coupled complex Ginzburg-Landau equations. This is realized by superimposing the lower and upper cutoff modes of wave propagation and by employing the multiple scale expansions in the semidiscrete approximation. We explore the modified Hirota method to analytically obtain the bright-bright pulse soliton solutions of our nonlinearly coupled equations. With these bright solitons as initial conditions of our numerical scheme, and knowing that electrical signals are the basis of information transfer in the nervous system, it is found that prior to collisions at the boundaries of the network, neural information is purely conveyed by bisolitons at lower cutoff mode. After collision, the bisolitons are completely annihilated and neural information is now relayed by the upper cutoff mode via the propagation of plane waves. It is also shown that the linear gain of the system is inextricably linked to the complex physiological mechanisms of ion mobility, since the speeds and spatial profiles of the coupled nerve impulses vary with the gain. A linear stability analysis performed on the coupled system mainly confirms the instability of plane waves in the neural network, with a glaring example of the transition of weak plane waves into a dark soliton and then static kinks. Numerical simulations have confirmed the annihilation phenomenon subsequent to collision in neural systems. They equally showed that the symmetry breaking of the pulse solution of the system leaves in the network static internal modes, sometime referred to as Goldstone modes.
Sliding mode control on electro-mechanical systems
Directory of Open Access Journals (Sweden)
Vadim I. Utkin
2002-01-01
Full Text Available The first sliding mode control application may be found in the papers back in the 1930s in Russia. With its versatile yet simple design procedure the methodology is proven to be one of the most powerful solutions for many practical control designs. For the sake of demonstration this paper is oriented towards application aspects of sliding mode control methodology. First the design approach based on the regularization is generalized for mechanical systems. It is shown that stability of zero dynamics should be taken into account when the regular form consists of blocks of second-order equations. Majority of applications in the paper are related to control and estimation methods of automotive industry. New theoretical methods are developed in the context of these studies: sliding made nonlinear observers, observers with binary measurements, parameter estimation in systems with sliding mode control.
Exploring extra dimensions through inflationary tensor modes
Im, Sang Hui; Nilles, Hans Peter; Trautner, Andreas
2018-03-01
Predictions of inflationary schemes can be influenced by the presence of extra dimensions. This could be of particular relevance for the spectrum of gravitational waves in models where the extra dimensions provide a brane-world solution to the hierarchy problem. Apart from models of large as well as exponentially warped extra dimensions, we analyze the size of tensor modes in the Linear Dilaton scheme recently revived in the discussion of the "clockwork mechanism". The results are model dependent, significantly enhanced tensor modes on one side and a suppression on the other. In some cases we are led to a scheme of "remote inflation", where the expansion is driven by energies at a hidden brane. In all cases where tensor modes are enhanced, the requirement of perturbativity of gravity leads to a stringent upper limit on the allowed Hubble rate during inflation.
The Fermi-Pasta-Ulam Model Periodic Solutions
Arioli, G; Terracini, S
2003-01-01
We introduce two novel methods for studying periodic solutions of the FPU beta-model, both numerically and rigorously. One is a variational approach, based on the dual formulation of the problem, and the other involves computer-assisted proofs. These methods are used e.g. to construct a new type of solutions, whose energy is spread among several modes, associated with closely spaced resonances.
On the spectral analysis of iterative solutions of the discretized one-group transport equation
International Nuclear Information System (INIS)
Sanchez, Richard
2004-01-01
We analyze the Fourier-mode technique used for the spectral analysis of iterative solutions of the one-group discretized transport equation. We introduce a direct spectral analysis for the iterative solution of finite difference approximations for finite slabs composed of identical layers, providing thus a complementary analysis that is more appropriate for reactor applications. Numerical calculations for the method of characteristics and with the diamond difference approximation show the appearance of antisymmetric modes generated by the iteration on boundary data. We have also utilized the discrete Fourier transform to compute the spectrum for a periodic slab containing N identical layers and shown that at the limit N → ∞ one obtains the familiar Fourier-mode solution
An engineering approach to common mode failure analysis
International Nuclear Information System (INIS)
Gangloff, W.C.; Franke, T.H.
1975-01-01
Safety systems for nuclear reactors can be designed using standard reliability engineering techniques such that system failure due to random component faults is extremely unlikely. However, the common-mode failure where several components fail together from a common cause is not susceptible to prevention by the usual tactics. In systems where a high degree of redundancy has been employed, the actual reliability of the system in service may be limited by common-mode failures. A methodical and thorough procedure for evaluation of system vulnerability to common-mode failures is presented. This procedure was developed for use in nuclear reactor safety systems and has been applied specifically to reactor protection. The method offers a qualitative assessment of a system whereby weak points can be identified and the resistance to common-mode failure can be judged. It takes into account all factors influencing system performance including design, manufacturing, installation, operation, testing, and maintenance. It is not a guarantee or sure solution, but rather a practical tool which can provide good assurance that the probability of common-mode protection failure has been made acceptably low. (author)
Ratcliffe, James G.; Johnston, William M., Jr.
2014-01-01
Mixed mode I-mode II interlaminar tests were conducted on IM7/8552 tape laminates using the mixed-mode bending test. Three mixed mode ratios, G(sub II)/G(sub T) = 0.2, 0.5, and 0.8, were considered. Tests were performed at all three mixed-mode ratios under quasi-static and cyclic loading conditions, where the former static tests were used to determine initial loading levels for the latter fatigue tests. Fatigue tests at each mixed-mode ratio were performed at four loading levels, Gmax, equal to 0.5G(sub c), 0.4G(sub c), 0.3G(sub c), and 0.2G(sub c), where G(sub c) is the interlaminar fracture toughness of the corresponding mixed-mode ratio at which a test was performed. All fatigue tests were performed using constant-amplitude load control and delamination growth was automatically documented using compliance solutions obtained from the corresponding quasi-static tests. Static fracture toughness data yielded a mixed-mode delamination criterion that exhibited monotonic increase in Gc with mixed-mode ratio, G(sub II)/G(sub T). Fatigue delamination onset parameters varied monotonically with G(sub II)/G(sub T), which was expected based on the fracture toughness data. Analysis of non-normalized data yielded a monotonic change in Paris law exponent with mode ratio. This was not the case when normalized data were analyzed. Fatigue data normalized by the static R-curve were most affected in specimens tested at G(sub II)/G(sub T)=0.2 (this process has little influence on the other data). In this case, the normalized data yielded a higher delamination growth rate compared to the raw data for a given loading level. Overall, fiber bridging appeared to be the dominant mechanism, affecting delamination growth rates in specimens tested at different load levels and differing mixed-mode ratios.
Nonlinear Vibration and Mode Shapes of FG Cylindrical Shells
Directory of Open Access Journals (Sweden)
Saeed Mahmoudkhani
Full Text Available Abstract The nonlinear vibration and normal mode shapes of FG cylindrical shells are investigated using an efficient analytical method. The equations of motion of the shell are based on the Donnell’s non-linear shallow-shell, and the material is assumed to be gradually changed across the thickness according to the simple power law. The solution is provided by first discretizing the equations of motion using the multi-mode Galerkin’s method. The nonlinear normal mode of the system is then extracted using the invariant manifold approach and employed to decouple the discretized equations. The homotopy analysis method is finally used to determine the nonlinear frequency. Numerical results are presented for the backbone curves of FG cylindrical shells, nonlinear mode shapes and also the nonlinear invariant modal surfaces. The volume fraction index and the geometric properties of the shell are found to be effective on the type of nonlinear behavior and also the nonlinear mode shapes of the shell. The circumferential half-wave numbers of the nonlinear mode shapes are found to change with time especially in a thinner cylinder.
Tearing mode dynamics and sawtooth oscillation in Hall-MHD
Ma, Zhiwei; Zhang, Wei; Wang, Sheng
2017-10-01
Tearing mode instability is one of the most important dynamic processes in space and laboratory plasmas. Hall effects, resulted from the decoupling of electron and ion motions, could cause the fast development and perturbation structure rotation of the tearing mode and become non-negligible. We independently developed high accuracy nonlinear MHD code (CLT) to study Hall effects on the dynamic evolution of tearing modes with Tokamak geometries. It is found that the rotation frequency of the mode in the electron diamagnetic direction is in a good agreement with analytical prediction. The linear growth rate increases with increase of the ion inertial length, which is contradictory to analytical solution in the slab geometry. We further find that the self-consistently generated rotation largely alters the dynamic behavior of the double tearing mode and the sawtooth oscillation. National Magnetic Confinement Fusion Science Program of China under Grant No. 2013GB104004 and 2013GB111004.
Performance analysis of a novel energy storage system based on liquid carbon dioxide
International Nuclear Information System (INIS)
Wang, Mingkun; Zhao, Pan; Wu, Yi; Dai, Yiping
2015-01-01
Due to the intermittence and fluctuation of wind resource, the increasing penetration level of wind power will bring huge challenges to maintain the stability of power system. Integrating compressed air energy storage (CAES) system with wind farms can weaken this negative effect. However CAES system needs large caverns or mines to store compressed air, which is restricted in application. In this paper, a novel energy storage system based on liquid carbon dioxide is presented. The mathematical models of compressed liquid-carbon dioxide energy storage system are developed. The parametric analysis is conducted to examine the effect of some key thermodynamic parameters on the system performance. Compared with AA-CAES, the liquid carbon dioxide energy storage system has advantages such as a high energy density, high EVR. Moreover, the round trip efficiency of this system can reach about 56.64%, which is acceptable in consideration of the storage volume. Therefore, this proposed system has a good potential for storing wind power in large scale and offers an attractive solution to the challenges of the increasing penetration level of wind power. - Highlights: • A novel energy storage system based on liquid carbon dioxide is presented. • The effects of some key parameters on the system performance are studied. • The operation optimization is conducted by genetic algorithm. • Comparative analysis of AA-CAES and liquid carbon dioxide system is studied.
Explosive attractor solutions to a universal cubic delay equation
Sanz-Orozco, D.; Berk, H. L.
2017-05-01
New explosive attractor solutions have been found in a universal cubic delay equation that has been studied in both the plasma and the fluid mechanics literature. Through computational simulations and analytic approximations, it is found that the oscillatory component of the explosive mode amplitude solutions are described through multi-frequency Fourier expansions with respect to a pseudo-time variable. The spectral dependence of these solutions as a function of a system parameter, ϕ , is studied. The mode amplitude that is described in the explosive regime has two main features: a well-known envelope ( t 0 - t ) - 5 / 2 , with t0 the blow-up time of the amplitude, and a spectrum of discrete oscillations with ever-increasing frequencies, which may give experimental information about the properties of a system's equilibrium.
Compressed air energy storage with waste heat export: An Alberta case study
International Nuclear Information System (INIS)
Safaei, Hossein; Keith, David W.
2014-01-01
Highlights: • Export of compression waste heat from CAES facilities for municipal heating can be profitable. • D-CAES concept has a negative abatement cost of −$40/tCO 2 e under the studied circumstances. • Economic viability of D-CAES highly depends on distance between air storage site and heat load. - Abstract: Interest in compressed air energy storage (CAES) technology has been renewed driven by the need to manage variability form rapidly growing wind and solar capacity. Distributed CAES (D-CAES) design aims to improve the efficiency of conventional CAES through locating the compressor near concentrated heating loads so capturing additional revenue through sales of compression waste heat. A pipeline transports compressed air to the storage facility and expander, co-located at some distance from the compressor. The economics of CAES are strongly dependant on electricity and gas markets in which they are embedded. As a case study, we evaluated the economics of two hypothetical merchant CAES and D-CAES facilities performing energy arbitrage in Alberta, Canada using market data from 2002 to 2011. The annual profit of the D-CAES plant was $1.3 million more on average at a distance of 50 km between the heat load and air storage sites. Superior economic and environmental performance of D-CAES led to a negative abatement cost of −$40/tCO 2 e. We performed a suite of sensitivity analyses to evaluate the impact of size of heat load, size of air storage, ratio of expander to compressor size, and length of pipeline on the economic feasibility of D-CAES
Investigation of water and saline solution drops evaporation on a solid substrate
Directory of Open Access Journals (Sweden)
Orlova Evgenija G.
2014-01-01
Full Text Available Experimental investigation water and saline solution drops evaporation on a solid substrate made of anodized aluminum is presented in the paper. Parameters characterizing drop profile have been obtained (contact angle, contact diameter, height. The specific evaporation rate has been calculated from obtained values. It was found that water and saline solution drops with concentration up to 9.1% evaporate in the pinning mode. However, with increasing the salt concentration in the solution up to 16.7% spreading mode was observed. Two stages of drop evaporation depending on change of the evaporation rate have been separated.
A Coupled Thermo-Hydro-Mechanical Model of Jointed Hard Rock for Compressed Air Energy Storage
Directory of Open Access Journals (Sweden)
Xiaoying Zhuang
2014-01-01
Full Text Available Renewable energy resources such as wind and solar are intermittent, which causes instability when being connected to utility grid of electricity. Compressed air energy storage (CAES provides an economic and technical viable solution to this problem by utilizing subsurface rock cavern to store the electricity generated by renewable energy in the form of compressed air. Though CAES has been used for over three decades, it is only restricted to salt rock or aquifers for air tightness reason. In this paper, the technical feasibility of utilizing hard rock for CAES is investigated by using a coupled thermo-hydro-mechanical (THM modelling of nonisothermal gas flow. Governing equations are derived from the rules of energy balance, mass balance, and static equilibrium. Cyclic volumetric mass source and heat source models are applied to simulate the gas injection and production. Evaluation is carried out for intact rock and rock with discrete crack, respectively. In both cases, the heat and pressure losses using air mass control and supplementary air injection are compared.
On the ordinary mode instability for low beta plasmas
Energy Technology Data Exchange (ETDEWEB)
Hadi, F.; Qamar, A. [Institute of Physics and Electronics, University of Peshawar, Peshawar (Pakistan); Bashir, M. F. [Department of Physics, G. C. University, Lahore (Pakistan); Salam Chair in Physics, G. C. University, Lahore (Pakistan); Yoon, P. H. [Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742-2431 (United States); School of Space Research, Kyung Hee University, Yongin (Korea, Republic of); Schlickeiser, R. [Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- and Astrophysik, Ruhr-Universität, Bochum (Germany)
2014-05-15
The purely growing ordinary (O) mode instability, first discussed by Davidson and Wu [Phys. Fluids 13, 1407 (1970)], has recently received renewed attention owing to its potential applicability to the solar wind plasma. In a series of papers, Ibscher, Schlickeiser, and their colleagues [Phys. Plasmas 19, 072116 (2012); ibid. 20, 012103 (2013); ibid. 20, 042121 (2013); ibid. 21, 022110 (2014)] revisited the O mode instability and extended it to the low-beta plasma regime by considering a counter-streaming bi-Maxwellian model. However, the O-mode instability is, thus, far discussed only on the basis of the marginal stability condition rather than actual numerical solutions of the dispersion relation. The present paper revisits the O-mode instability by considering the actual complex roots. The marginal stability condition as a function of the (electron) temperature anisotropy and beta naturally emerges in such a scheme.
Optimal Control of Micro Grid Operation Mode Seamless Switching Based on Radau Allocation Method
Chen, Xiaomin; Wang, Gang
2017-05-01
The seamless switching process of micro grid operation mode directly affects the safety and stability of its operation. According to the switching process from island mode to grid-connected mode of micro grid, we establish a dynamic optimization model based on two grid-connected inverters. We use Radau allocation method to discretize the model, and use Newton iteration method to obtain the optimal solution. Finally, we implement the optimization mode in MATLAB and get the optimal control trajectory of the inverters.
Adiabatic Compressed Air Energy Storage with packed bed thermal energy storage
International Nuclear Information System (INIS)
Barbour, Edward; Mignard, Dimitri; Ding, Yulong; Li, Yongliang
2015-01-01
Highlights: • The paper presents a thermodynamic analysis of A-CAES using packed bed regenerators. • The packed beds are used to store the compression heat. • A numerical model is developed, validated and used to simulate system operation. • The simulated efficiencies are between 70.5% and 71.1% for continuous operation. • Heat build-up in the beds reduces continuous cycle efficiency slightly. - Abstract: The majority of articles on Adiabatic Compressed Air Energy Storage (A-CAES) so far have focussed on the use of indirect-contact heat exchangers and a thermal fluid in which to store the compression heat. While packed beds have been suggested, a detailed analysis of A-CAES with packed beds is lacking in the available literature. This paper presents such an analysis. We develop a numerical model of an A-CAES system with packed beds and validate it against analytical solutions. Our results suggest that an efficiency in excess of 70% should be achievable, which is higher than many of the previous estimates for A-CAES systems using indirect-contact heat exchangers. We carry out an exergy analysis for a single charge–storage–discharge cycle to see where the main losses are likely to transpire and we find that the main losses occur in the compressors and expanders (accounting for nearly 20% of the work input) rather than in the packed beds. The system is then simulated for continuous cycling and it is found that the build-up of leftover heat from previous cycles in the packed beds results in higher steady state temperature profiles of the packed beds. This leads to a small reduction (<0.5%) in efficiency for continuous operation
Thermo-dynamic analysis and simulation of a combined air and hydro energy storage (CAHES) system
International Nuclear Information System (INIS)
Bi, Xianyun; Liu, Pei; Li, Zheng
2016-01-01
Large-scale energy storage is essential for the stability of a grid, especially for those with large proportion of intermittent renewable energy sources. The efficiency of a conventional compressed air energy storage (CAES) technology is limited by compression heat loss and changing working conditions. In this manuscript, a combined air and hydro energy storage (CAHES) system is proposed, which realizes a higher exergy efficiency compared with conventional CAES systems by reducing compression heat losses and addressing issues of changing working conditions through thermal compensation from solar radiation. The configuration and two operating modes of the proposed CAHES system are firstly introduced, followed by theoretical analysis and numerical simulation under different operating modes to analyze system performances. Impacts of external and internal factors on the system performances are analyzed. The practical feasibility of the system is also investigated. Results show that the exergy efficiency of the system reaches approximately 50%, whilst the charging electricity ratio reaches over 80%. - Highlights: • A combined air and hydro energy storage system is proposed. • High exergy efficiency is achieved and consumption of fossil fuel is eliminated. • The system performance is affected by compression ratio and solar radiation.
NCBI nr-aa BLAST: CBRC-SCER-06-0000 [SEVENS
Lifescience Database Archive (English)
Full Text Available CBRC-SCER-06-0000 emb|CAE52261.1| Ste2p [Saccharomyces cerevisiae] emb|CAE52272.1| Ste2p [Saccharo...myces cerevisiae] emb|CAE52274.1| Ste2p [Saccharomyces cerevisiae] CAE52261.1 0.0 98% ...
Economics of compressed air energy storage to integrate wind power: A case study in ERCOT
Energy Technology Data Exchange (ETDEWEB)
Fertig, Emily, E-mail: efertig@andrew.cmu.ed [Carnegie Mellon Electricity Industry Center, Department of Engineering and Public Policy and Tepper School of Business, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States); Apt, Jay [Carnegie Mellon Electricity Industry Center, Department of Engineering and Public Policy and Tepper School of Business, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States)
2011-05-15
Compressed air energy storage (CAES) could be paired with a wind farm to provide firm, dispatchable baseload power, or serve as a peaking plant and capture upswings in electricity prices. We present a firm-level engineering-economic analysis of a wind/CAES system with a wind farm in central Texas, load in either Dallas or Houston, and a CAES plant whose location is profit-optimized. With 2008 hourly prices and load in Houston, the economically optimal CAES expander capacity is unrealistically large - 24 GW - and dispatches for only a few hours per week when prices are highest; a price cap and capacity payment likewise results in a large (17 GW) profit-maximizing CAES expander. Under all other scenarios considered the CAES plant is unprofitable. Using 2008 data, a baseload wind/CAES system is less profitable than a natural gas combined cycle (NGCC) plant at carbon prices less than $56/tCO{sub 2} ($15/MMBTU gas) to $230/tCO{sub 2} ($5/MMBTU gas). Entering regulation markets raises profit only slightly. Social benefits of CAES paired with wind include avoided construction of new generation capacity, improved air quality during peak times, and increased economic surplus, but may not outweigh the private cost of the CAES system nor justify a subsidy. - Research highlights: {yields} Sizes of CAES and transmission paired with a Texas wind farm are optimized for profit. {yields} A profit-maximizing wind farm owner would not invest in a dedicated CAES system. {yields} The social benefit of a wind/CAES system is unlikely to outweigh private cost. {yields} CAES cannot cost-effectively smooth wind power with plausible imminent carbon prices.
Economics of compressed air energy storage to integrate wind power: A case study in ERCOT
International Nuclear Information System (INIS)
Fertig, Emily; Apt, Jay
2011-01-01
Compressed air energy storage (CAES) could be paired with a wind farm to provide firm, dispatchable baseload power, or serve as a peaking plant and capture upswings in electricity prices. We present a firm-level engineering-economic analysis of a wind/CAES system with a wind farm in central Texas, load in either Dallas or Houston, and a CAES plant whose location is profit-optimized. With 2008 hourly prices and load in Houston, the economically optimal CAES expander capacity is unrealistically large - 24 GW - and dispatches for only a few hours per week when prices are highest; a price cap and capacity payment likewise results in a large (17 GW) profit-maximizing CAES expander. Under all other scenarios considered the CAES plant is unprofitable. Using 2008 data, a baseload wind/CAES system is less profitable than a natural gas combined cycle (NGCC) plant at carbon prices less than $56/tCO 2 ($15/MMBTU gas) to $230/tCO 2 ($5/MMBTU gas). Entering regulation markets raises profit only slightly. Social benefits of CAES paired with wind include avoided construction of new generation capacity, improved air quality during peak times, and increased economic surplus, but may not outweigh the private cost of the CAES system nor justify a subsidy. - Research highlights: → Sizes of CAES and transmission paired with a Texas wind farm are optimized for profit. → A profit-maximizing wind farm owner would not invest in a dedicated CAES system. → The social benefit of a wind/CAES system is unlikely to outweigh private cost. → CAES cannot cost-effectively smooth wind power with plausible imminent carbon prices.
Arbitrarily large numbers of kink internal modes in inhomogeneous sine-Gordon equations
Energy Technology Data Exchange (ETDEWEB)
González, J.A., E-mail: jalbertgonz@yahoo.es [Department of Physics, Florida International University, Miami, FL 33199 (United States); Department of Natural Sciences, Miami Dade College, 627 SW 27th Ave., Miami, FL 33135 (United States); Bellorín, A., E-mail: alberto.bellorin@ucv.ve [Escuela de Física, Facultad de Ciencias, Universidad Central de Venezuela, Apartado Postal 47586, Caracas 1041-A (Venezuela, Bolivarian Republic of); García-Ñustes, M.A., E-mail: monica.garcia@pucv.cl [Instituto de Física, Pontificia Universidad Católica de Valparaíso, Casilla 4059 (Chile); Guerrero, L.E., E-mail: lguerre@usb.ve [Departamento de Física, Universidad Simón Bolívar, Apartado Postal 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of); Jiménez, S., E-mail: s.jimenez@upm.es [Departamento de Matemática Aplicada a las TT.II., E.T.S.I. Telecomunicación, Universidad Politécnica de Madrid, 28040-Madrid (Spain); Vázquez, L., E-mail: lvazquez@fdi.ucm.es [Departamento de Matemática Aplicada, Facultad de Informática, Universidad Complutense de Madrid, 28040-Madrid (Spain)
2017-06-28
We prove analytically the existence of an infinite number of internal (shape) modes of sine-Gordon solitons in the presence of some inhomogeneous long-range forces, provided some conditions are satisfied. - Highlights: • We have found exact kink solutions to the perturbed sine-Gordon equation. • We have been able to study analytically the kink stability problem. • A kink equilibrated by an exponentially-localized perturbation has a finite number of oscillation modes. • A sufficiently broad equilibrating perturbation supports an infinite number of soliton internal modes.
Impacts of operating conditions and solution chemistry on osmotic membrane structure and performance
Wong, Mavis C.Y.; Martinez, Kristina; Ramon, Guy Z.; Hoek, Eric M.V.
2012-01-01
Herein, we report on changes in the performance of a commercial cellulose triacetate (CTA) membrane, imparted by varied operating conditions and solution chemistries. Changes to feed and draw solution flow rate did not significantly alter the CTA membrane's water permeability, salt permeability, or membrane structural parameter when operated with the membrane skin layer facing the draw solution (PRO-mode). However, water and salt permeability increased with increasing feed or draw solution temperature, while the membrane structural parameter decreased with increasing draw solution, possibly due to changes in polymer intermolecular interactions. High ionic strength draw solutions may de-swell the CTA membrane via charge neutralization, which resulted in lower water permeability, higher salt permeability, and lower structural parameter. This observed trend was further exacerbated by the presence of divalent cations which tends to swell the polymer to a greater extent. Finally, the calculated CTA membrane's structural parameter was lower and less sensitive to external factors when operated in PRO-mode, but highly sensitive to the same factors when the skin layer faced the feed solution (FO-mode), presumably due to swelling/de-swelling of the saturated porous substructure by the draw solution. This is a first attempt aimed at systematically evaluating the changes in performance of the CTA membrane due to operating conditions and solution chemistry, shedding new insight into the possible advantages and disadvantages of this material in certain applications. © 2011 Elsevier B.V.
Impacts of operating conditions and solution chemistry on osmotic membrane structure and performance
Wong, Mavis C.Y.
2012-02-01
Herein, we report on changes in the performance of a commercial cellulose triacetate (CTA) membrane, imparted by varied operating conditions and solution chemistries. Changes to feed and draw solution flow rate did not significantly alter the CTA membrane\\'s water permeability, salt permeability, or membrane structural parameter when operated with the membrane skin layer facing the draw solution (PRO-mode). However, water and salt permeability increased with increasing feed or draw solution temperature, while the membrane structural parameter decreased with increasing draw solution, possibly due to changes in polymer intermolecular interactions. High ionic strength draw solutions may de-swell the CTA membrane via charge neutralization, which resulted in lower water permeability, higher salt permeability, and lower structural parameter. This observed trend was further exacerbated by the presence of divalent cations which tends to swell the polymer to a greater extent. Finally, the calculated CTA membrane\\'s structural parameter was lower and less sensitive to external factors when operated in PRO-mode, but highly sensitive to the same factors when the skin layer faced the feed solution (FO-mode), presumably due to swelling/de-swelling of the saturated porous substructure by the draw solution. This is a first attempt aimed at systematically evaluating the changes in performance of the CTA membrane due to operating conditions and solution chemistry, shedding new insight into the possible advantages and disadvantages of this material in certain applications. © 2011 Elsevier B.V.
Directory of Open Access Journals (Sweden)
Qi Wang
2016-06-01
Full Text Available A cascaded symmetrical dual-taper Mach-Zehnder interferometer structure based on guided-mode and leaky-mode interference is proposed in this paper. Firstly, the interference spectrum characteristics of interferometer has been analyzed by the Finite Difference-Beam Propagation Method (FD-BPM. When the diameter of taper waist is 20 μm–30 μm, dual-taper length is 1 mm and taper distance is 4 cm–6 cm, the spectral contrast is higher, which is suitable for sensing. Secondly, experimental research on refractive index sensitivity is carried out. A refractive index sensitivity of 62.78 nm/RIU (refractive index unit can achieved in the RI range of 1.3333–1.3792 (0%~25% NaCl solution, when the sensor structure parameters meet the following conditions: diameter of taper waist is 24 μm, dual-taper length is 837 μm and taper distance is 5.5 cm. The spectrum contrast is 0.8 and measurement resolution is 1.6 × 10−5 RIU. The simulation analysis is highly consistent with experimental results. Research shows that the sensor has promising application in low RI fields where high-precision measurement is required due to its high sensitivity and stability.
On the wing behaviour of the overtones of self-localized modes
Dusi, R.; Wagner, M.
1998-08-01
In this paper the solutions for self-localized modes in a nonlinear chain are investigated. We present a converging iteration procedure, which is based on analytical information of the wings and which takes into account higher overtones of the solitonic oscillations. The accuracy is controlled in a step by step manner by means of a Gaussian error analysis. Our numerical procedure allows for highly accurate solutions, in all anharmonicity regimes, and beyond the rotating-wave approximation (RWA). It is found that the overtone wings change their analytical behaviour at certain critical values of the energy of the self-localized mode: there is a turnover in the exponent of descent. The results are shown for a Fermi-Pasta-Ulam (FPU) chain with quartic anharmonicity.
Influence of the leaching mode on the durability of a glass for fission product containment
International Nuclear Information System (INIS)
Nogues, J.L.; Terki, A.
1984-06-01
The chemical durability of a glass containing wastes from light water reactor (LWR) has been studied with three different lixiviation modes: ''static'' leach test, ''soxhlet'' test and ''continuous flow'' test. After a description of these tests, the leaching mode influence on the glass durability is reported as obtained from weight loss measurements, analyses of the leaching solutions and surface analyses of the samples. Finally, the corrosion mechanisms of this type of glass are approached and a phenomenological explanation of attack from an aqueous solution is proposed [fr
Elevator mode convection in flows with strong magnetic fields
Energy Technology Data Exchange (ETDEWEB)
Liu, Li; Zikanov, Oleg, E-mail: zikanov@umich.edu [Department of Mechanical Engineering, University of Michigan-Dearborn, 48128-1491 Michigan (United States)
2015-04-15
Instability modes in the form of axially uniform vertical jets, also called “elevator modes,” are known to be the solutions of thermal convection problems for vertically unbounded systems. Typically, their relevance to the actual flow state is limited by three-dimensional breakdown caused by rapid growth of secondary instabilities. We consider a flow of a liquid metal in a vertical duct with a heated wall and strong transverse magnetic field and find elevator modes that are stable and, thus, not just relevant, but a dominant feature of the flow. We then explore the hypothesis suggested by recent experimental data that an analogous instability to modes of slow axial variation develops in finite-length ducts, where it causes large-amplitude fluctuations of temperature. The implications for liquid metal blankets for tokamak fusion reactors that potentially invalidate some of the currently pursued design concepts are discussed.
Energy Technology Data Exchange (ETDEWEB)
Coppola, Anthony [General Motors Company, Flint, MI (United States); Faruque, Omar [Ford Motor Company, Dearborn, MI (United States); Truskin, James F [FCA US LLC, Auburn Hills, MI (United States); Board, Derek [Ford Motor Company, Dearborn, MI (United States); Jones, Martin [Ford Motor Company, Dearborn, MI (United States); Tao, Jian [FCA US LLC, Auburn Hills, MI (United States); Chen, Yijung [Ford Motor Company, Dearborn, MI (United States); Mehta, Manish [M-Tech International LLC, Dubai (United Arab Emirates)
2017-09-27
advances in order to assess the correlation of the predicted results to the physical tests. The FBCC was developed to meet a goal of 30-35% mass reduction while aiming for equivalent energy absorption as a steel component for which baseline experimental results were obtained from testing in the same crash modes. The project also evaluated crash performance of thermoplastic composite structures fabricated from commercial prepreg materials and low cost carbon fiber sourced from Oak Ridge National Laboratory. The VMM Project determined that no set of predictions from a CAE supplier were found to be universally accurate among all the six crash modes evaluated. In general, crash modes that were most dependent on the properties of the prepreg were more accurate than those that were dependent on the behavior of the joints. The project found that current CAE modeling methods or best practices for carbon fiber composites have not achieved standardization, and accuracy of CAE is highly reliant on the experience of its users. Coupon tests alone are not sufficient to develop an accurate material model, but it is necessary to bridge the gap between the coupon data and performance of the actual structure with a series of subcomponent level tests. Much of the unreliability of the predictions can be attributed to shortcomings in our ability to mathematically link the effects of manufacturing and material variability into the material models. This is a subject of ongoing research in the industry. The final report is organized by key technical tasks to describe how the validation project developed, modeled and compared crash data obtained on the composite FBCC to the multiple sets of CAE predictions. Highlights of the report include a discussion of the quantitative comparison between predictions and experimental data, as well as an in-depth discussion of remaining technological gaps that exist in the industry, which are intended to spur innovations and improvements in CAE technology.
Analytical solution for the mode conversion equations with steep exponential density profiles
International Nuclear Information System (INIS)
Alava, M.J.; Heikkinen, J.A.
1992-01-01
A general analytical solution for the converted power from the fast magnetosonic wave to an ion Bernstein wave in a magnetized plasma with an exponential steeply increasing density profile is given in the closed form. The solution covers both the conversion at the lower-hybrid resonance and the conversion through the density gradient for small parallel wave numbers. As an application, the conversion coefficients at the scrape-off layer plasma are estimated in the context of ion cyclotron heating of a tokamak plasma
Non-equipotential magnetic surfaces and mode-transition in tokamaks
International Nuclear Information System (INIS)
Li Xingzhong
1988-01-01
The solution of the Fokker-Planck equation is used to describe a phase transition in velocity space. This transition is related to the mode-transition in tokamaks. After the transition the electrostatic potential on a magnetic surface cannot be considered as a constant. (orig.)
International Nuclear Information System (INIS)
Kurihara, Kazuyoshi; Otomo, Akira; Syouji, Atsushi; Takahara, Junichi; Suzuki, Koji; Yokoyama, Shiyoshi
2007-01-01
Analytic solutions to the superfocusing modes of surface plasmon polaritons in a conical geometry are theoretically studied using an ingenious method called the quasi-separation of variables. This method can be used to look for fundamental solutions to the wave equation for a field that must satisfy boundary conditions at all points on the continuous surface of tapered geometries. The set of differential equations exclusively separated from the wave equation can be consistently solved in combination with perturbation methods. This paper presents the zeroth-order perturbation solution of conical superfocusing modes with azimuthal symmetry and graphically represents them in electric field-line patterns
Accurately bi-orthogonal direct and adjoint lambda modes via two-sided Eigen-solvers
International Nuclear Information System (INIS)
Roman, J.E.; Vidal, V.; Verdu, G.
2005-01-01
This work is concerned with the accurate computation of the dominant l-modes (Lambda mode) of the reactor core in order to approximate the solution of the neutron diffusion equation in different situations such as the transient modal analysis. In a previous work, the problem was already addressed by implementing a parallel program based on SLEPc (Scalable Library for Eigenvalue Problem Computations), a public domain software for the solution of eigenvalue problems. Now, the proposed solution is extended by incorporating also the computation of the adjoint l-modes in such a way that the bi-orthogonality condition is enforced very accurately. This feature is very desirable in some types of analyses, and in the proposed scheme it is achieved by making use of two-sided eigenvalue solving software. Current implementations of some of these software, while still susceptible of improvement, show that they can be competitive in terms of response time and accuracy with respect to other types of eigenvalue solving software. The code developed by the authors has parallel capabilities in order to be able to analyze reactors with a great level of detail in a short time. (authors)
Accurately bi-orthogonal direct and adjoint lambda modes via two-sided Eigen-solvers
Energy Technology Data Exchange (ETDEWEB)
Roman, J.E.; Vidal, V. [Valencia Univ. Politecnica, D. Sistemas Informaticos y Computacion (Spain); Verdu, G. [Valencia Univ. Politecnica, D. Ingenieria Quimica y Nuclear (Spain)
2005-07-01
This work is concerned with the accurate computation of the dominant l-modes (Lambda mode) of the reactor core in order to approximate the solution of the neutron diffusion equation in different situations such as the transient modal analysis. In a previous work, the problem was already addressed by implementing a parallel program based on SLEPc (Scalable Library for Eigenvalue Problem Computations), a public domain software for the solution of eigenvalue problems. Now, the proposed solution is extended by incorporating also the computation of the adjoint l-modes in such a way that the bi-orthogonality condition is enforced very accurately. This feature is very desirable in some types of analyses, and in the proposed scheme it is achieved by making use of two-sided eigenvalue solving software. Current implementations of some of these software, while still susceptible of improvement, show that they can be competitive in terms of response time and accuracy with respect to other types of eigenvalue solving software. The code developed by the authors has parallel capabilities in order to be able to analyze reactors with a great level of detail in a short time. (authors)
Hanzawa, Nobutomo; Saitoh, Kuimasa; Sakamoto, Taiji; Matsui, Takashi; Tsujikawa, Kyozo; Koshiba, Masanori; Yamamoto, Fumihiko
2013-11-04
We proposed a PLC-based mode multi/demultiplexer (MUX/DEMUX) with an asymmetric parallel waveguide for mode division multiplexed (MDM) transmission. The mode MUX/DEMUX including a mode conversion function with an asymmetric parallel waveguide can be realized by matching the effective indices of the LP(01) and LP(11) modes of two waveguides. We report the design of a mode MUX/DEMUX that can support C-band WDM-MDM transmission. The fabricated mode MUX/DEMUX realized a low insertion loss of less than 1.3 dB and high a mode extinction ratio that exceeded 15 dB. We used the fabricated mode MUX/DEMUX to achieve a successful 2 mode x 4 wavelength x 10 Gbps transmission over a 9 km two-mode fiber with a penalty of less than 1 dB.
3-D near-field imaging of guided modes in nanophotonic waveguides
Directory of Open Access Journals (Sweden)
Ziegler Jed I.
2017-04-01
Full Text Available Highly evanescent waveguides with a subwavelength core thickness present a promising lab-on-chip solution for generating nanovolume trapping sites using overlapping evanescent fields. In this work, we experimentally studied Si3N4 waveguides whose sub-wavelength cross-sections and high aspect ratios support fundamental and higher order modes at a single excitation wavelength. Due to differing modal effective indices, these co-propagating modes interfere and generate beating patterns with significant evanescent field intensity. Using near-field scanning optical microscopy (NSOM, we map the structure of these beating modes in three dimensions. Our results demonstrate the potential of NSOM to optimize waveguide design for complex field trapping devices. By reducing the in-plane width, the population of competing modes decreases, resulting in a simplified spectrum of beating modes, such that waveguides with a width of 650 nm support three modes with two observed beats. Our results demonstrate the potential of NSOM to optimize waveguide design for complex field trapping devices.
Appearance of eigen modes for the linearized Vlasov-Poisson equation
International Nuclear Information System (INIS)
Degond, P.
1983-01-01
In order to determine the asymptotic behaviour, when the time goes to infinity, of the solution of the linearized Vlasov-Poisson equation, we use eigen modes, associated to continuous linear functionals on a Banach space of analytic functions [fr
Preventive Methods for ATM Mode Control
Ivan Baronak; Robert Trska
2004-01-01
Broadband transfer mode ATM represent one of alternative solutions for growing requirements on transfer capabilities. Its advantage is an effort for provisions of guaranteed quality of transport services with preservations of high transfer rate. This property is covered by several mechanisms, which role is to control not only the traffic of existing connections, but also the admission of new ones and prevent the violation of requirements on transport quality of existing and new connections.
Oliver E. Buckley Condensed Matter Prize: Emergent gravity from interacting Majorana modes
Kitaev, Alexei
I will describe a concrete many-body Hamiltonian that exhibits some features of a quantum black hole. The Sachdev-Ye-Kitaev model is a system of N >> 1 Majorana modes that are all coupled by random 4-th order terms. The problem admits an approximate dynamic mean field solution. At low temperatures, there is a fluctuating collective mode that corresponds to reparametrization of time. The effective action for this mode is equivalent to dilaton gravity in two space-time dimensions. Some important questions are how to quantize the reparametrization mode in Lorentzian time, include dissipative effects, and understand this system from the quantum information perspective. Supported by the Simons Foundation, Award Number 376205.
International Nuclear Information System (INIS)
He Qibing; Peng Qiyang; Qu Wenxiao
1993-09-01
The effect of energetic trapped particles on the stabilization of ballooning modes in finite-aspect-ratio tokamaks is numerically analyzed. The numerical solution of boundary value problem of an integro-differential equation is successfully obtained by RKF integral method with variable step size. The results show that the instability domain of ballooning modes becomes small along with the increase of energetic particles pressure. The energetic trapped particles can partially or completely suppress the instability of ballooning modes
A Novel Hybrid-Fuel Storage System of Compressed Air Energy for China
Directory of Open Access Journals (Sweden)
Wenyi Liu
2014-08-01
Full Text Available Compressed air energy storage (CAES is a large-scale technology that provides long-duration energy storage. It is promising for balancing the large-scale penetration of intermittent and dispersed sources of power, such as wind and solar power, into electric grids. The existing CAES plants utilize natural gas (NG as fuel. However, China is rich in coal but is deficient in NG; therefore, a hybrid-fuel CAES is proposed and analyzed in this study. Based on the existing CAES plants, the hybrid-fuel CAES incorporates an external combustion heater into the power generation subsystem to heat the air from the recuperator and the air from the high-pressure air turbine. Coal is the fuel for the external combustion heater. The overall efficiency and exergy efficiency of the hybrid-fuel CAES are 61.18% and 59.84%, respectively. Given the same parameters, the cost of electricity (COE of the hybrid-fuel CAES, which requires less NG, is $5.48/MW∙h less than that of the gas-fuel CAES. Although the proposed CAES requires a relatively high investment in the current electricity system in North China, the proposed CAES will be likely to become competitive in the market, provided that the energy supplies are improved and the large scale grid-connection of wind power is realized.
Spatial mode structures of electrostatic drift waves in a collisional cylindrical helicon plasma
DEFF Research Database (Denmark)
Schröder, C.; Grulke, O.; Klinger, T.
2004-01-01
In a cylindrical helicon plasma, mode structures of coherent drift waves are studied in the poloidal plane, the plane perpendicular to the ambient magnetic field. The mode structures rotate with a constant angular velocity in the direction of the electron diamagnetic drift and show significant...... radial bending. The experimental observations are compared with numerical solutions of a linear nonlocal cylindrical model for drift waves [ Ellis , Plasma Phys. 22, 113 (1980) ]. In the numerical model, a transition to bended mode structures is found if the plasma collisionality is increased....... This finding proves that the experimentally observed bended mode structures are the result of high electron collisionality. (C) 2004 American Institute of Physics....
New applications of Boson's coherent states of double modes at regular product
International Nuclear Information System (INIS)
Zhang Yongde; Ren Yong
1987-05-01
This paper presents a series of new applications of boson's coherent states of double modes by means of the technique of regular products. They include non-coupled double oscillator solutions at two time dependent extra-sources; coupled double oscillator solutions at two time dependent extra-sources; some applications to regular momentum theory; an explicit expression for time-reversal operator. (author). 7 refs
Study of the zero modes of the Faddeev–Popov operator in the maximal Abelian gauge
International Nuclear Information System (INIS)
Capri, M.A.L.; Guimaraes, M.S.; Lemes, V.E.R.; Sorella, S.P.; Tedesco, D.G.
2014-01-01
A study of the zero modes of the Faddeev–Popov operator in the maximal Abelian gauge is presented in the case of the gauge group SU(2) and for different Euclidean space–time dimensions. Explicit examples of classes of normalizable zero modes and corresponding gauge field configurations are constructed by taking into account two boundary conditions, namely: (i) the finite Euclidean Yang–Mills action, (ii) the finite Hilbert norm. -- Highlights: •We study the zero modes of the Faddeev–Popov operator in the maximal Abelian gauge. •For d=2 we obtain solutions with finite action but not finite Hilbert norm. •For d=3,4 we obtain solutions with finite action and finite Hilbert norm. •These results can be compared with those previously obtained in the Landau gauge
PLC-based mode multi/demultiplexers for mode division multiplexing
Saitoh, Kunimasa; Hanzawa, Nobutomo; Sakamoto, Taiji; Fujisawa, Takeshi; Yamashita, Yoko; Matsui, Takashi; Tsujikawa, Kyozo; Nakajima, Kazuhide
2017-02-01
Recently developed PLC-based mode multi/demultiplexers (MUX/DEMUXs) for mode division multiplexing (MDM) transmission are reviewed. We firstly show the operation principle and basic characteristics of PLC-based MUX/DEMUXs with an asymmetric directional coupler (ADC). We then demonstrate the 3-mode (2LP-mode) multiplexing of the LP01, LP11a, and LP11b modes by using fabricated PLC-based mode MUX/DEMUX on one chip. In order to excite LP11b mode in the same plane, a PLC-based LP11 mode rotator is introduced. Finally, we show the PLC-based 6-mode (4LP-mode) MUX/DEMUX with a uniform height by using ADCs, LP11 mode rotators, and tapered waveguides. It is shown that the LP21a mode can be excited from the LP11b mode by using ADC, and the two nearly degenerated LP21b and LP02 modes can be (de)multiplexed separately by using tapered mode converter from E13 (E31) mode to LP21b (LP02) mode.
Fundamental burn-up mode in a pebble-bed type reactor
International Nuclear Information System (INIS)
Chen, Xue-Nong; Kiefhaber, Edgar; Maschek, Werner
2008-01-01
This paper deals with a pebble-bed type reactor, in which the fuel is loaded from one side (top) and discharged from the other side (bottom). A boundary value problem of a single group diffusion equation coupled with simplified burn-up equations is studied, where the natural radioactive decay processes are neglected in the burn-up modelling. An asymptotic burning wave solution is found analytically in the one-dimensional case, which is called as fundamental burn-up mode. Among this solution family there are two particular cases, namely, a classic fundamental solution with a zero burn-up and a partial solitary burn-up wave solution with a highest burn-up. An example of Th-U conversion is considered and the solutions are presented in order to show the mechanism of the burning wave. (author)
Elevator convection modes in vertical ducts with strong transverse magnetic fields
Zikanov, Oleg; Liu, Li
2014-11-01
Instability modes in the form of axially uniform vertical jets, also called ``elevator modes,'' are known to be solutions of thermal convection problems for vertically unbounded systems. Typically, their relevance to an actual flow state is limited, since they quickly break down to secondary instabilities. We consider a downward flow of a liquid metal in a vertical duct with a heated wall and strong transverse magnetic field and find elevator modes that are likely to be not just relevant, but a dominant feature of the flow. Recent experiments indicate that counterparts of such modes may develop in vertically finite ducts leading to high-amplitude fluctuations of temperature. Potential implications for designs of liquid metal blankets for fusion reactors with poloidal ducts are discussed. Financial support was provided by the US NSF (Grant CBET 1232851).
Effect of toroidicity during lower hybrid mode conversion
International Nuclear Information System (INIS)
Riyopoulos, S.; Mahajan, S.
1985-11-01
The effect of toroidicity during lower hybrid mode conversion is examined by treating the wave propagation in an inhomogeneous medium as an eigenvalue problem for ω 2 (m,n),m,n poloidal and toroidal wave numbers. Since the frequency regime near ω 2 = ω/sub LH/ 2 is an accumulation point for the eigenvalue spectrum, the degenerate perturbation technique must be applied. The toroidal eigenmodes are constructed by a zeroth order superposition of monochromatic solutions with different poloidal dependence m, thus they generically exhibit a wide spectrum in k/sub parallel/ for given fixed ω 2 even for small inverse aspect ratio epsilon. In case that the average is in the neighborhood of k/sub min/, the minimum wave number for accessibility of the mode conversion regime, it is expected that excitation of toroidal modes rather than geometric optics will determine the wave coupling to the plasma
Using quasi-guided modes for modeling the transfer behavior of bent dielectric slab waveguides
Directory of Open Access Journals (Sweden)
M. Stallein
2010-09-01
Full Text Available The connection of two straight dielectric multimode slab waveguides by a circular bent waveguide is analyzed by means of quasi-guided modes. These modes correspond to the well known leaky modes, but own real eigenvalues, thus the mathematical description is simpler. Furthermore they are derived as approximate solutions of the exact theory. This work will first give a brief introduction to the basic theory, followed by a discussion of the properties of quasi-guided modes. After a validation by comparison with a numerical simulation using the Finite Integration Technique, results for the bending loss of multimode waveguides are presented.
Linear stability analysis of collective neutrino oscillations without spurious modes
Morinaga, Taiki; Yamada, Shoichi
2018-01-01
Collective neutrino oscillations are induced by the presence of neutrinos themselves. As such, they are intrinsically nonlinear phenomena and are much more complex than linear counterparts such as the vacuum or Mikheyev-Smirnov-Wolfenstein oscillations. They obey integro-differential equations, for which it is also very challenging to obtain numerical solutions. If one focuses on the onset of collective oscillations, on the other hand, the equations can be linearized and the technique of linear analysis can be employed. Unfortunately, however, it is well known that such an analysis, when applied with discretizations of continuous angular distributions, suffers from the appearance of so-called spurious modes: unphysical eigenmodes of the discretized linear equations. In this paper, we analyze in detail the origin of these unphysical modes and present a simple solution to this annoying problem. We find that the spurious modes originate from the artificial production of pole singularities instead of a branch cut on the Riemann surface by the discretizations. The branching point singularities on the Riemann surface for the original nondiscretized equations can be recovered by approximating the angular distributions with polynomials and then performing the integrals analytically. We demonstrate for some examples that this simple prescription does remove the spurious modes. We also propose an even simpler method: a piecewise linear approximation to the angular distribution. It is shown that the same methodology is applicable to the multienergy case as well as to the dispersion relation approach that was proposed very recently.
Sub-wavelength grating mode transformers in silicon slab waveguides.
Bock, Przemek J; Cheben, Pavel; Schmid, Jens H; Delâge, André; Xu, Dan-Xia; Janz, Siegfried; Hall, Trevor J
2009-10-12
We report on several new types of sub-wavelength grating (SWG) gradient index structures for efficient mode coupling in high index contrast slab waveguides. Using a SWG, an adiabatic transition is achieved at the interface between silicon-on-insulator waveguides of different geometries. The SWG transition region minimizes both fundamental mode mismatch loss and coupling to higher order modes. By creating the gradient effective index region in the direction of propagation, we demonstrate that efficient vertical mode transformation can be achieved between slab waveguides of different core thickness. The structures which we propose can be fabricated by a single etch step. Using 3D finite-difference time-domain simulations we study the loss, polarization dependence and the higher order mode excitation for two types (triangular and triangular-transverse) of SWG transition regions between silicon-on-insulator slab waveguides of different core thicknesses. We demonstrate two solutions to reduce the polarization dependent loss of these structures. Finally, we propose an implementation of SWG structures to reduce loss and higher order mode excitation between a slab waveguide and a phase array of an array waveguide grating (AWG). Compared to a conventional AWG, the loss is reduced from -1.4 dB to < -0.2 dB at the slab-array interface.
Solute redistribution studies in oxidised zirconium alloys
Energy Technology Data Exchange (ETDEWEB)
Khera, S K; Kale, G B; Gadiyar, H S [Bhabha Atomic Research Centre, Bombay (India). Metallurgy Div.
1977-01-01
Electron microprobe studies on solute distribution in oxide layers and in the regions near oxide metal interface have been carried out in the case of zircaloy-2 and zirconium binary alloys containing niobium, tin, iron, copper, chromium and nickel and oxidised in steam at 550 deg C. In the case of alloys having higher oxidation rates, the oxide of solute element was found to dissolve in ZrO/sub 2/ without any composition variation. However, for solute addition with limited solubility like Cr, Cu and Fe, solute enrichment at metal/oxide interface and depletion of the same matrix has been observed. The intensity profiles for nickel distribution were also found to be identical to Fe or Cr distribution. The mode of solute distribution has been discussed in relation to oxidation behaviour of these alloys.
Dynamics of temporally localized states in passively mode-locked semiconductor lasers
Schelte, C.; Javaloyes, J.; Gurevich, S. V.
2018-05-01
We study the emergence and the stability of temporally localized structures in the output of a semiconductor laser passively mode locked by a saturable absorber in the long-cavity regime. For large yet realistic values of the linewidth enhancement factor, we disclose the existence of secondary dynamical instabilities where the pulses develop regular and subsequent irregular temporal oscillations. By a detailed bifurcation analysis we show that additional solution branches that consist of multipulse (molecules) solutions exist. We demonstrate that the various solution curves for the single and multipeak pulses can splice and intersect each other via transcritical bifurcations, leading to a complex web of solutions. Our analysis is based on a generic model of mode locking that consists of a time-delayed dynamical system, but also on a much more numerically efficient, yet approximate, partial differential equation. We compare the results of the bifurcation analysis of both models in order to assess up to which point the two approaches are equivalent. We conclude our analysis by the study of the influence of group velocity dispersion, which is only possible in the framework of the partial differential equation model, and we show that it may have a profound impact on the dynamics of the localized states.
Mode locking and spatiotemporal chaos in periodically driven Gunn diodes
DEFF Research Database (Denmark)
Mosekilde, Erik; Feldberg, Rasmus; Knudsen, Carsten
1990-01-01
oscillation entrains with the external signal. This produces a devil’s staircase of frequency-locked solutions. At higher microwave amplitudes, period doubling and other forms of mode-converting bifurcations can be seen. In this interval the diode also exhibits spatiotemporal chaos. At still higher microwave...
Controlling the stability of nonlinear optical modes via electromagnetically induced transparency
Zhang, Kun; Liang, Yi-zeng; Lin, Ji; Li, Hui-jun
2018-02-01
We propose a scheme to generate and stabilize the high-dimensional spatial solitons via electromagnetically induced transparency (EIT). The system we consider is a resonant atomic ensemble having Λ configuration. We illustrate that under EIT conditions the equation satisfied by the probe field envelope is reduced to a saturable nonlinear Schrödinger equation with the trapping potential, provided by a far-detuned laser field and a random magnetic field. We present high-dimensional soliton solutions exhibiting many interesting characteristics, including diversity (i.e., many different types of soliton solutions can be found, including bright, ring multipole bright, ring multipole defect mode, multiring bright, multiring defect mode, and vortices solitons), the phase transition between bright soliton and higher-order defect modes (i.e., the phase transition can be realized by controlling the nonlinear coefficient or the intensity of the trapping potential), and stability (i.e., various solitons can be stabilized by the Gaussian potential provided by the far detuned laser field, or the random potential provided by the magnetic field). We also find that some solitons are the extension of the linear eigenmode, whereas others entirely derive from the role of nonlinearity. Compared with previous studies, we not only show the diverse soliton solutions in the same system but also find the boundary of the phase transition for the type of solitons. In addition, we present the possibility of using the random potential to stabilize various solitons and vortices.
Damping in nuclear collective modes in a semiclassical fluid-dynamical approximation
International Nuclear Information System (INIS)
Vignolo, C.E.; Hernandez, Susana
1989-01-01
A semiclassical fluiddynamical model based on an usual scaling approximation (SCA) was extended to investigate the role of one and two-body dissipation in the widths of nuclear collective modes. The competition between one and two-body viscosity in: i) the collisionless (elastic) limit; ii) the hydrodynamical case and iii) the general viscoelastic regime is examined over the whole range of nuclear collision time scales. Numerical solutions are investigated for the first magnetic 2 - twist mode in 208 Pb. (Author) [es
Investigating Proenvironmental Behavior: The Case of Commuting Mode Choice
Trinh, Tu Anh; Phuong Linh Le, Thi
2018-04-01
The central aim of this article is to investigate mode choice behavior among commuters in Ho Chi Minh City using disaggregate mode choice model and norm activation theory. A better understanding of commuters’ choice of transport mode provide an opportunity to obtain valuable information on their travel behaviors which help to build a basic for proffering solutions stimulating commuters to switch to public transport, which in turn contribute to deal with traffic problems and environmental issues. Binary logistic regression was employed under disaggregate choice method. Key findings indicated that Demographic factors including Age (-0.308), Married (-9.089), Weather (-8.272); Trip factors including Travel cost (0.437), Travel distance (0.252), and Norm activation theory (Awareness of consequences: AC2 (-1.699), AC4 (2.951), AC6 (-3.523), AC7 (-2.092), AC9 (-3.045), AC11 (+ 2.939), and Personal norms: PN2 (-2.695)) had strong impact on the commuters’ mode choice. Although motorcycle was the major transport mode among commuters, they presented their willingness to switch to bus transport if it had less negative impacts on the environment and their daily living environment.
The INGECAD multidisciplinary integrated computer aided engineering system
International Nuclear Information System (INIS)
Kisielewicz, L.T.
1989-01-01
The purpose of this paper is to define the key criteria of an integrated CAE system, and to discuss the solution developed by Ingevision to match these criteria. An information flow model of process plant engineering is presented as a background to the key criteria of CAE systems. This model includes multidisciplinary interfaces and project changes up to the as-built stage. The key quality criteria of CAE systems correspond to managerial issues, such as project control, to technical issues, consistency and quality assurance, and to economical issues, such as cost optimization. The INGECAD system answers these criteria with a tripod nucleus underlying a set of specialized applications. The nucleus includes a Data Base Management System, basic Graphical Tools, and a Decision Support System. The paper overviews the different modules of the INGECAD system emphasizing the general architecture and the basic tools. Specific examples are developed in functional design, cost optimized items selection, and semi-automated routing of piping system. These examples are not intended to illustrate exhaustively the capabilities of the INGECAD system, but rather to highlight some of the advantages the multidisciplinary integration of the system provides to the users. (orig./HP)
Decay modes of two repulsively interacting bosons
International Nuclear Information System (INIS)
Kim, Sungyun; Brand, Joachim
2011-01-01
We study the decay of two repulsively interacting bosons tunnelling through a delta potential barrier by a direct numerical solution of the time-dependent Schroedinger equation. The solutions are analysed according to the regions of particle presence: both particles inside the trap (in-in), one particle in and one particle out (in-out) and both particles outside (out-out). It is shown that the in-in probability is dominated by the exponential decay, and its decay rate is predicted very well from outgoing boundary conditions. Up to a certain range of interaction strength, the decay of in-out probability is dominated by the single-particle decay mode. The decay mechanisms are adequately described by simple models.
Spatial-mode switchable ring fiber laser based on low mode-crosstalk all-fiber mode MUX/DEMUX
Ren, Fang; Yu, Jinyi; Wang, Jianping
2018-05-01
We report an all-fiber ring laser that emits linearly polarized (LP) modes based on the intracavity all-fiber mode multiplexer/demultiplexer (MUX/DEMUX). Multiple LP modes in ring fiber laser are generated by taking advantage of mode MUX/DEMUX. The all-fiber mode MUX/DEMUX are composed of cascaded mode-selective couplers (MSCs). The output lasing mode of the ring fiber laser can be switched among the three lowest-order LP modes by employing combination of a mode MUX and a simple N × 1 optical switch. The slope efficiencies, optical spectra and mode profiles are measured.
Lloyd, Nicholas S; Sadekov, Aleksey Yu; Misra, Sambuddha
2018-01-15
Boron isotope ratios (δ 11 B values) are used as a proxy for seawater paleo-pH, amongst several other applications. The analytical precision can be limited by the detection of low intensity ion beams from limited sample amounts. High-gain amplifiers offer improvements in signal/noise ratio and can be used to increase measurement precision and reduce sample amounts. 10 13 ohm amplifier technology has previously been applied to several radiogenic systems, but has thus far not been applied to non-traditional stable isotopes. Here we apply 10 13 ohm amplifier technology for the measurement of boron isotope ratios using solution mode MC-ICP-MS and laser ablation mode (LA-)MC-ICP-MS techniques. Precision is shown for reference materials as well as for low-volume foraminifera samples. The baseline uncertainty for a 0.1 pA 10 B + ion beam is reduced to ohm amplifier technology is demonstrated to offer advantages for the determination of δ 11 B values by both MC-ICP-MS and LA-MC-ICP-MS for small samples of biogenic carbonates, such as foraminifera shells. 10 13 ohm amplifier technology will also be of benefit to other non-traditional stable isotope measurements. Copyright © 2017 John Wiley & Sons, Ltd.
Quasi-normal modes from non-commutative matrix dynamics
Aprile, Francesco; Sanfilippo, Francesco
2017-09-01
We explore similarities between the process of relaxation in the BMN matrix model and the physics of black holes in AdS/CFT. Focusing on Dyson-fluid solutions of the matrix model, we perform numerical simulations of the real time dynamics of the system. By quenching the equilibrium distribution we study quasi-normal oscillations of scalar single trace observables, we isolate the lowest quasi-normal mode, and we determine its frequencies as function of the energy. Considering the BMN matrix model as a truncation of N=4 SYM, we also compute the frequencies of the quasi-normal modes of the dual scalar fields in the AdS5-Schwarzschild background. We compare the results, and we finda surprising similarity.
Accretion-induced quasinormal mode excitation of a Schwarzschild black hole
International Nuclear Information System (INIS)
Nagar, Alessandro; Zanotti, Olindo; Font, Jose A.; Rezzolla, Luciano
2007-01-01
By combining the numerical solution of the nonlinear hydrodynamics equations with the solution of the linear inhomogeneous Zerilli-Moncrief and Regge-Wheeler equations, we investigate the properties of the gravitational radiation emitted during the axisymmetric accretion of matter onto a Schwarzschild black hole. The matter models considered include quadrupolar dust shells and thick accretion disks, permitting us to simulate situations which may be encountered at the end stages of stellar gravitational collapse or binary neutron star merger. We focus on the interference pattern appearing in the energy spectra of the emitted gravitational waves and on the amount of excitation of the quasinormal modes of the accreting black hole. We show that, quite generically in the presence of accretion, the black-hole ringdown is not a simple superposition of quasinormal modes, although the fundamental mode is usually present and often dominates the gravitational-wave signal. We interpret this as due to backscattering of waves off the nonexponentially decaying part of the black-hole potential and to the finite spatial extension of the accreting matter. Our results suggest that the black-hole QNM contributions to the full gravitational-wave signal should be extremely small and possibly not detectable in generic astrophysical scenarios involving the accretion of extended distributions of matter
An optical channel modeling of a single mode fiber
Nabavi, Neda; Liu, Peng; Hall, Trevor James
2018-05-01
The evaluation of the optical channel model that accurately describes the single mode fibre as a coherent transmission medium is reviewed through analytical, numerical and experimental analysis. We used the numerical modelling of the optical transmission medium and experimental measurements to determine the polarization drift as a function of time for a fixed length of fibre. The probability distribution of the birefringence vector was derived, which is associated to the 'Poole' equation. The theory and experimental evidence that has been disclosed in the literature in the context of polarization mode dispersion - Stokes & Jones formulations and solutions for key statistics by integration of stochastic differential equations has been investigated. Besides in-depth definition of the single-mode fibre-optic channel, the modelling which concerns an ensemble of fibres each with a different instance of environmental perturbation has been analysed.
Core-SOL simulations of L-mode tokamak plasma discharges using BALDUR code
Directory of Open Access Journals (Sweden)
Yutthapong Pinanroj
2014-04-01
Full Text Available Core-SOL simulations were carried out of plasma in tokamak reactors operating in a low confinement mode (L-mode, for various conditions that match available experimental data. The simulation results were quantitatively compared against experimental data, showing that the average RMS errors for electron temperature, ion temperature, and electron density were lower than 16% or less for 14 L-mode discharges from two tokamaks named DIII-D and TFTR. In the simulations, the core plasma transport was described using a combination of neoclassical transport calculated by NCLASS module and anomalous transport by Multi-Mode-Model version 2001 (MMM2001. The scrape-off-layer (SOL is the small amount of residual plasma that interacts with the tokamak vessel, and was simulated by integrating the fluid equations, including sources, along open field lines. The SOL solution provided the boundary conditions of core plasma region on low confinement mode (L-mode. The experimental data were for 14 L-mode discharges and from two tokamaks, named DIII-D and TFTR.
Interaction of the ATA beam with the TM030 mode of the accelerating cells
International Nuclear Information System (INIS)
Neil, V.K.
1985-01-01
The interaction of the electron beam in the Advanced Test Accelerator with an azimuthally symmetric mode of the accelerating cells is investigated theoretically. The interaction possibly could cause modulation of the beam current at the resonant frequency of the mode. Values of the shunt impedance and Q value of the mode were obtained from previous measurement and analysis. Lagranian hydrodynamics is employed and a WKB solution to the equation of motion is obtained. Results indicate that the interaction will not be a problem in the accelerator
Exact bidirectional X -wave solutions in fiber Bragg gratings
Efremidis, Nikolaos K.; Nye, Nicholas S.; Christodoulides, Demetrios N.
2017-10-01
We find exact solutions describing bidirectional pulses propagating in fiber Bragg gratings. They are derived by solving the coupled-mode theory equations and are expressed in terms of products of modified Bessel functions with algebraic functions. Depending on the values of the two free parameters, the general bidirectional X -wave solution can also take the form of a unidirectional pulse. We analyze the symmetries and the asymptotic properties of the solutions and also discuss additional waveforms that are obtained by interference of more than one solution. Depending on their parameters, such pulses can create a sharp focus with high contrast.
Effects of radial envelope modulations on the collisionless trapped-electron mode in tokamak plasmas
Chen, Hao-Tian; Chen, Liu
2018-05-01
Adopting the ballooning-mode representation and including the effects of radial envelope modulations, we have derived the corresponding linear eigenmode equation for the collisionless trapped-electron mode in tokamak plasmas. Numerical solutions of the eigenmode equation indicate that finite radial envelope modulations can affect the linear stability properties both quantitatively and qualitatively via the significant modifications in the corresponding eigenmode structures.
Computation of mode eigenfunctions in graded-index optical fibers by the propagating beam method
International Nuclear Information System (INIS)
Feit, M.D.; Fleck, J.A. Jr.
1980-01-01
The propagating beam method utilizes discrete Fourier transforms for generating configuration-space solutions to optical waveguide problems without reference to modes. The propagating beam method can also give a complete description of the field in terms of modes by a Fourier analysis with respect to axial distance of the computed fields. Earlier work dealt with the accurate determination of mode propagation constants and group delays. In this paper the method is extended to the computation of mode eigenfunctions. The method is efficient, allowing generation of a large number of eigenfunctions from a single propagation run. Computations for parabolic-index profiles show excellent agreement between analytic and numerically generated eigenfunctions
Creating a Community of Practice: Lessons Learned from the Center for Astronomy Education (Invited)
Brissenden, G.
2009-12-01
The Center for Astronomy Education (CAE) is devoted to improving teaching and learning in Astro 101. To accomplish this, a vital part of CAE is our broader community of practice which includes over 1000 instructors, graduate and undergraduate students, and postdocs. It is this greater community of practice that supports each other, helps, and learns from each other beyond what would be possible without it. As our community of practice has grown, we at CAE have learned many lessons about how different facets of CAE can best be used to promote and support our community both as a whole and for individual members. We will discuss the various facets of CAE, such as our online discussion group Astrolrner@CAE (http://astronomy101.jpl.nasa.gov/discussion) and its Guest Moderator program, our CAE Regional Teaching Exchange Coordinator program, our CAE Workshop Presenter Apprenticeship Training program, our online This Month’s Teaching Strategy, monthly newsletters, and various types of socializing and networking sessions we hold at national meetings. But more importantly, we will discuss the lessons we’ve learned about what does and does not work in building community within each of these facets.
Energy Technology Data Exchange (ETDEWEB)
Maxwell, D.M.
1992-12-31
The ability of endogenous carboxylesterase (CaE) to protect against the lethal effects of a variety of organophosphorus (OP) compounds was examined in rats. The in vivo protection provided by endogenous CaE was measured by the difference in the LD50 values of OP compounds in controlrats and rats whose CaE activity had been inhibited by sc injection with2 mg/kg of 2-(O cresyl)-4H-1,3,2-benzodi oxaphosphorin-2-oxide. Endogenous CaE provided significant protection against the in vivo toxicity of soman, sarin, tabun, and paraoxon, but not against dichlorvos, diisopropyl fluorophosphate, or ethoxymethyl-S-2- (DIISOPROPYLAMINO)ETHYL THIOPHOSPHONATE (VX). The relationship between the in vivo CaE protection against OP compounds and their relative reactivities with CaE and acetylcholinesterase (AChE) was evaluated by measuring the in vitro bimolecular rate constants (ki) for inhibition of plasma CaE and brain AChE. Except for VX, ki values for CaE inhibition varied <10-fold while ki values for AChE inhibition varied 105-fold. Chemical warfare agents, Nerve agents, Organophosphoruscompound soman, VX, Carboxylesterase, Protection, Pretreatment.
Penetration of internal gravity waveguide modes into the upper atmosphere
Directory of Open Access Journals (Sweden)
Rudenko G.V.
2016-03-01
Full Text Available The paper describes internal gravity waveguide modes, using dissipative solutions above the source. We compare such a description with an accurate approach and a WKB approximation for dissipationless equations. For waveguide disturbances, dispersion relations calculated by any method are shown to be close to each other and to be in good agreement with observed characteristics of traveling ionospheric disturbances. Unlike other methods, dissipative solutions above the source allow us to adequately describe the spatial structure of disturbances in the upper atmosphere.
Study of the mode of angular velocity damping for a spacecraft at non-standard situation
Davydov, A. A.; Sazonov, V. V.
2012-07-01
Non-standard situation on a spacecraft (Earth's satellite) is considered, when there are no measurements of the spacecraft's angular velocity component relative to one of its body axes. Angular velocity measurements are used in controlling spacecraft's attitude motion by means of flywheels. The arising problem is to study the operation of standard control algorithms in the absence of some necessary measurements. In this work this problem is solved for the algorithm ensuring the damping of spacecraft's angular velocity. Such a damping is shown to be possible not for all initial conditions of motion. In the general case one of two possible final modes is realized, each described by stable steady-state solutions of the equations of motion. In one of them, the spacecraft's angular velocity component relative to the axis, for which the measurements are absent, is nonzero. The estimates of the regions of attraction are obtained for these steady-state solutions by numerical calculations. A simple technique is suggested that allows one to eliminate the initial conditions of the angular velocity damping mode from the attraction region of an undesirable solution. Several realizations of this mode that have taken place are reconstructed. This reconstruction was carried out using approximations of telemetry values of the angular velocity components and the total angular momentum of flywheels, obtained at the non-standard situation, by solutions of the equations of spacecraft's rotational motion.
Evaporation of a non-ideal solution and its application to writing ink aging.
Cantú, Antonio A
2015-02-01
The evaporation of a solution consisting of a non-volatile solute dissolved in a volatile solvent has been previously treated using a simple model called the beaker model. This model considers the solution to be in a non-porous container that has vertical walls like a glass beaker and assumes the solution is an ideal solution so that Raoult's law is obeyed. A particular novel finding was that under a certain condition, the evaporation or aging curve of the solution has a point of maximum acceleration. Prior to this point, the solution is in its fast drying mode and after this point, it is in its slow drying mode. This phenomenon is observed in the drying of many writing inks. In this work this model is modified to consider the evaporation of (a) a non-ideal solution, (b) a solution that become saturated, (c) a solution on a glass slide, and (d) a solution on a porous substrate. In each of these cases, the existence and location of the point of maximum acceleration of the drying process are examined. These modifications lead to a description of the dying process of a solution that is remarkably similar to that of writing inks but obtained via an entirely different physical model. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
Sound-like collective mode excitation with pion absorption in nuclear matter
International Nuclear Information System (INIS)
Qiu Xijiun; Shen Jianguo; Huang Lingfang
1985-01-01
The relativistic mean field theory consistent with bulk properties of nuclear matter is extended to study the excitations of the sound-like collective modes in nuclear matter. Corresponding relativistic mean field equations are solved numerically and self-consistently. The effective mass of nucleon, the speed of the sound and the amplitude of the sound-like solution are calculated. When the nuclear density is near or greater than the saturation density, the sound-like non-trivial solution could be found
Lim, Seol-Wa; Lee, Dong-Ryung; Choi, Bong-Keun; Kim, Hong-Suk; Yang, Seung Hwan; Suh, Joo-Won; Kim, Kyung Soo
2016-12-01
To evaluate the possible protective effect of Citrus aurantium peel extract (CAE) against apoptosis in cholestatic liver fibrosis induced by bile duct ligation in mice. Male ICR mice were divided to 5 groups: 1) Control group (Sham-operated mice), 2) Cholestatic liver injury group induced by bile duct ligation (BDL), 3) BDL mice treated with silymarin (200 mg/kg) for 4 weeks, 4) BDL mice treated with 50 mg/kg CAE for 4 weeks, 5) BDL mice treated with 200 mg/kg CAE for 4 weeks. Mice were sacrificed and liver fibrosis was evaluated by serum and hepatic tissue biochemistry tests and liver histopathological examination. Effects of CAE on inflammation and apoptosis gene regulation were investigated through real-time PCR. CAE effect on lipid metabolism related signaling was determined by western blot analysis. In BDL mice, administration of CAE for 4 weeks markedly attenuated liver fibrosis based on histopathological alteration. Serum and hepatic tissue biochemistry results revealed that CAE (50 and 200 mg/kg) decreased the levels of alanine transaminase, aspartate transaminase, gamma-glutamyl transferase, total bilirubin, nitric oxide, and thiobarbituric acid reactive substances. Real-time PCR and western blot analysis showed that CAE regulated inflammation, apoptosis, and lipid metabolism factors increased by BDL. Interleukin family, tumor necrosis factor α, and related apoptosis factors mRNA levels were increased by BDL treatment. However, these increases were suppressed by CAE administration. In addition, CAE effectively increased phosphorylation of AMP-activated protein kinase, nuclear factor E2-related factor 2, and related cytoprotective proteins. CAE can efficiently regulate BDL-induced liver injury with antioxidant, anti-inflammatory, and anti-apoptotic activities. Copyright © 2016 Hainan Medical University. Production and hosting by Elsevier B.V. All rights reserved.
Hernández, M Victoria; Sanmartí, Raimon; Cañete, Juan D; Descalzo, Miguel A; Alsina, Mercè; Carmona, Loreto; Gomez-Reino, Juan J
2013-12-01
To analyze the incidence rate (IR) and risk factors of cutaneous adverse events (CAE) in patients with chronic inflammatory rheumatic diseases treated with tumor necrosis factor (TNF) antagonists. We analyzed all patients from the BIOBADASER (Base de Datos de Productos Biológicos de la Sociedad Española de Reumatología) registry treated with a TNF antagonist (infliximab, etanercept, or adalimumab). Data collected included age, sex, diagnosis and duration of rheumatic disease, type of TNF antagonist, and concomitant treatment. Type of CAE was classified as local or systemic cutaneous manifestation related to treatment administration (infusion reaction), infection, malignancy, or autoimmune skin disease. Time of onset of CAE and outcome were also recorded. The IRs of CAE per 1,000 patient-years of exposure with 95% confidence intervals (95% CIs) were estimated. Multivariable analysis was performed to identify potential risk factors for CAE. A total of 5,437 patients were included, representing 17,330 patient-years of exposure. A total of 920 CAE were reported; the IRs per 1,000 patient-years were 53 (95% CI 50-57) for CAE, 28 (95% CI 25-30) for infection, 15 (95% CI 13-17) for infusion reactions, 5 (95% CI 4-6) for autoimmune skin diseases, and 3 (95% CI 2-4) for skin malignancy. The mean time between starting TNF antagonist treatment and CAE was 1.78 years. In 32% of patients, CAE required TNF antagonist withdrawal. The main risk factors for CAE were female sex and treatment with infliximab, leflunomide, and glucocorticoids. The IR of CAE in patients treated with TNF antagonists is significant and should be addressed carefully, and withdrawal of therapy is required in some cases. Copyright © 2013 by the American College of Rheumatology.
Impact of mixed modes on measurement errors and estimates of change in panel data
Directory of Open Access Journals (Sweden)
Alexandru Cernat
2015-07-01
Full Text Available Mixed mode designs are receiving increased interest as a possible solution for saving costs in panel surveys, although the lasting effects on data quality are unknown. To better understand the effects of mixed mode designs on panel data we will examine its impact on random and systematic error and on estimates of change. The SF12, a health scale, in the Understanding Society Innovation Panel is used for the analysis. Results indicate that only one variable out of 12 has systematic differences due to the mixed mode design. Also, four of the 12 items overestimate variance of change in time in the mixed mode design. We conclude that using a mixed mode approach leads to minor measurement differences but it can result in the overestimation of individual change compared to a single mode design.
A model for a scrape-off-layer low-high (L-H) mode transition
International Nuclear Information System (INIS)
Cohen, R.H.; Xu, X.
1995-01-01
Increasing the radial mode number has a stabilizing effect on the conducting-wall and curvature-driven interchange modes in a tokamak scrape-off layer (SOL), arising from the increased polarization response. Such an effect is naturally imposed as the SOL width is decreased, and for a narrow-enough SOL, the stabilizing effect is stronger than the increase in the instability drives. By combining a mixing-length estimate for the thermal diffusivity with energy conservation and heat conduction equations and the condition of continuity of the heat flux at the separatrix, it is found that the resultant turbulence-transport system admits two solutions, one stable and one unstable, at different SOL widths; the inclusion of additional physics can add a second stable root at lower width. These roots are plausibly identified with SOL behavior in low (L) and high (H) modes. Particularly when a model is introduced for finite-β, finite-k parallel effects on the modes, a power threshold for transition to the narrower root is obtained, suggesting a possible L-H transition mechanism. The non-monotonic dependence of the turbulent heat flux vs SOL width and the possibility of multiple solutions for the equilibrium SOL width are verified with nonlinear simulations. copyright 1995 American Institute of Physics
Fermion zero modes and the black-hole hypermultiplet with rigid supersymmetry
International Nuclear Information System (INIS)
Brooks, R.; Kallosh, R.; Ortin, T.
1995-01-01
The gravitini zero modes riding on top of the extreme Reissner-Nordstroem black-hole solution of N=2 supergravity are shown to be normalizable. The gravitini and dilatini zero modes of axion-dilaton extreme black-hole solutions of N=4 supergravity are also given and found to have finite norms. These norms are duality invariant. The finiteness and positivity of the norms in both cases are found to be correlated with the Witten-Israel-Nester construction; however, we have replaced the Witten condition by the pure-spin-3/2 constraint on the gravitini. We compare our calculation of the norms with the calculations which provide the moduli space metric for extreme black holes. The action of the N=2 hypermultiplet with an off-shell central charge describes the solitons of N=2 supergravity. This action, in the Majumdar-Papapetrou multi-black-hole background, is shown to be N=2 rigidly supersymmetric
Kovasznay modes in the linear stability analysis of self-similar ablation flows
International Nuclear Information System (INIS)
Lombard, V.
2008-12-01
Exact self-similar solutions of gas dynamics equations with nonlinear heat conduction for semi-infinite slabs of perfect gases are used for studying the stability of ablative flows in inertial confinement fusion, when a shock wave propagates in front of a thermal front. Both the similarity solutions and their linear perturbations are numerically computed with a dynamical multi-domain Chebyshev pseudo-spectral method. Laser-imprint results, showing that maximum amplification occurs for a laser-intensity modulation of zero transverse wavenumber have thus been obtained (Abeguile et al. (2006); Clarisse et al. (2008)). Here we pursue this approach by proceeding for the first time to an analysis of perturbations in terms of Kovasznay modes. Based on the analysis of two compressible and incompressible flows, evolution equations of vorticity, acoustic and entropy modes are proposed for each flow region and mode couplings are assessed. For short times, perturbations are transferred from the external surface to the ablation front by diffusion and propagate as acoustic waves up to the shock wave. For long times, the shock region is governed by the free propagation of acoustic waves. A study of perturbations and associated sources allows us to identify strong mode couplings in the conduction and ablation regions. Moreover, the maximum instability depends on compressibility. Finally, a comparison with experiments of flows subjected to initial surface defects is initiated. (author)
Linear and nonlinear dynamics of electron temperature gradient mode in non-Maxwellian plasmas
Energy Technology Data Exchange (ETDEWEB)
Zakir, U.; Qamar, A. [Institute of Physics and Electronics, University of Peshawar, Peshawar (Pakistan); Haque, Q. [Theoretical Plasma Physics Division, PINSTECH, Islamabad (Pakistan); National Centre for Physics, Islamabad (Pakistan)
2013-05-15
The effect of non-Maxwellian distributed ions on electron temperature gradient mode is investigated. The linear dispersion relation of η{sub e}−mode is obtained which shows that the behavior of this mode changes in the presence of superthermal ions. The growth rate of η{sub e}−mode driven linear instability is found and is observed to modify due to nonthermal ions. However, it is found that this leaves the electron energy transport coefficient unchanged. In the nonlinear regime, a dipolar vortex solution is derived which indicates that the dynamic behavior of the vortices changes with the inclusion of kappa distributed ions. The importance of present study with respect to space and laboratory plasmas is also pointed out.
Tin Dioxide Electrolyte-Gated Transistors Working in Depletion and Enhancement Modes.
Valitova, Irina; Natile, Marta Maria; Soavi, Francesca; Santato, Clara; Cicoira, Fabio
2017-10-25
Metal oxide semiconductors are interesting for next-generation flexible and transparent electronics because of their performance and reliability. Tin dioxide (SnO 2 ) is a very promising material that has already found applications in sensing, photovoltaics, optoelectronics, and batteries. In this work, we report on electrolyte-gated, solution-processed polycrystalline SnO 2 transistors on both rigid and flexible substrates. For the transistor channel, we used both unpatterned and patterned SnO 2 films. Since decreasing the SnO 2 area in contact with the electrolyte increases the charge-carrier density, patterned transistors operate in the depletion mode, whereas unpatterned ones operate in the enhancement mode. We also fabricated flexible SnO 2 transistors that operate in the enhancement mode that can withstand moderate mechanical bending.
Numerical solution of the resistive magnetohydrodynamic boundary-layer equations
International Nuclear Information System (INIS)
Glasser, A.H.; Jardin, S.C.; Tesauro, G.
1983-10-01
Three different techniques are presented for numerical solution of the equations governing the boundary layer of resistive magnetohydrodynamic tearing and interchange instabilities in toroidal geometry. Excellent agreement among these methods and with analytical results provides confidence in the correctness of the results. Solutions obtained in regimes where analytical medthods fail indicate a new scaling for the tearing mode as well as the existence of a new regime of stability
Energy Technology Data Exchange (ETDEWEB)
Li, Jiawei; Huang, Wenhua [Department of Electronic Engineering and Information Science, University of Science and Technology of China, Hefei 230027 (China); Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi' an 710024 (China); Xiao, Renzhen; Bai, Xianchen; Zhang, Yuchuan; Zhang, Xiaowei; Shao, Hao; Chen, Changhua [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi' an 710024 (China); Zhu, Qi [Department of Electronic Engineering and Information Science, University of Science and Technology of China, Hefei 230027 (China)
2015-03-16
A dual-cavity TM{sub 02}–TM{sub 01} mode converter is designed for a dual-mode operation over-moded relativistic backward-wave oscillator. With the converter, the fundamental mode output is achieved. Particle-in-cell simulation shows that the efficiency of beam-wave conversion was over 46% and a pureTM{sub 01} mode output was obtained. Effects of end reflection provided by the mode converter were studied. Adequate TM{sub 01} mode feedback provided by the converter enhances conversion efficiency. The distance between the mode converter and extraction cavity critically affect the generation of microwaves depending on the reflection phase of TM{sub 01} mode feedback.
International Nuclear Information System (INIS)
Li, Jiawei; Huang, Wenhua; Xiao, Renzhen; Bai, Xianchen; Zhang, Yuchuan; Zhang, Xiaowei; Shao, Hao; Chen, Changhua; Zhu, Qi
2015-01-01
A dual-cavity TM 02 –TM 01 mode converter is designed for a dual-mode operation over-moded relativistic backward-wave oscillator. With the converter, the fundamental mode output is achieved. Particle-in-cell simulation shows that the efficiency of beam-wave conversion was over 46% and a pureTM 01 mode output was obtained. Effects of end reflection provided by the mode converter were studied. Adequate TM 01 mode feedback provided by the converter enhances conversion efficiency. The distance between the mode converter and extraction cavity critically affect the generation of microwaves depending on the reflection phase of TM 01 mode feedback
Cap-assisted endoscopic sclerotherapy for hemorrhoids: Methods, feasibility and efficacy
Zhang, Ting; Xu, Li-Juan; Xiang, Jie; He, Zhi; Peng, Zhao-Yuan; Huang, Guang-Ming; Ji, Guo-Zhong; Zhang, Fa-Ming
2015-01-01
AIM: To evaluate the methodology, feasibility, safety and efficacy of a novel method called cap-assisted endoscopic sclerotherapy (CAES) for internal hemorrhoids. METHODS: A pilot study on CAES for grade I to III internal hemorrhoids was performed. Colon and terminal ileum examination by colonoscopy was performed for all patients before starting CAES. Polypectomy and excision of anal papilla fibroma were performed if polyps or anal papilla fibroma were found and assessed to be suitable for resection under endoscopy. CAES was performed based on the requirement of the cap, endoscope, disposable endoscopic long injection needle, enough insufflated air and sclerosing agent. RESULTS: A total of 30 patients with grade I to III internal hemorrhoids was included. The follow-up was more than four weeks. No bleeding was observed after CAES. One (3.33%) patient claimed mild tenesmus within four days after CAES in that an endoscopist performed this procedure for the first time. One hundred percent of patients were satisfied with this novel procedure, especially for those patients who underwent CAES in conjunction with polypectomy or excision of anal papilla fibroma. CONCLUSION: CAES as a novel endoscopic sclerotherapy should be a convenient, safe and effective flexible endoscopic therapy for internal hemorrhoids. PMID:26722615
On-fiber 3D printing of photonic crystal fiber tapers for mode field diameter conversion
Bertoncini, Andrea; Rajamanickam, Vijayakumar Palanisamy; Liberale, Carlo
2017-01-01
The large mismatch between the Mode Field Diameter (MFD) of conventional single-mode fibers (SMFs) and the MFD of highly nonlinear Photonic Crystal Fibers (PCFs), that can be down to 1.5 μm, or Large Mode Area PCF, that can be up to 25 μm, would require a substantial fiber mode size rescaling in order to allow an efficient direct coupling between PCFs and SMFs. Over the years different solutions have been proposed, as fiber splicing of SMF to PCF. However these procedures are not straightforward, as they involve developing special splicing recipes, and can affect PCF optical properties at the splice interface [1].
On-fiber 3D printing of photonic crystal fiber tapers for mode field diameter conversion
Bertoncini, Andrea
2017-11-02
The large mismatch between the Mode Field Diameter (MFD) of conventional single-mode fibers (SMFs) and the MFD of highly nonlinear Photonic Crystal Fibers (PCFs), that can be down to 1.5 μm, or Large Mode Area PCF, that can be up to 25 μm, would require a substantial fiber mode size rescaling in order to allow an efficient direct coupling between PCFs and SMFs. Over the years different solutions have been proposed, as fiber splicing of SMF to PCF. However these procedures are not straightforward, as they involve developing special splicing recipes, and can affect PCF optical properties at the splice interface [1].
Assessment of market potential of compressed air energy storage systems
Boyd, D. W.; Buckley, O. E.; Clark, C. E., Jr.
1983-12-01
This report describes an assessment of potential roles that EPRI might take to facilitate the commercial acceptance of compressed air energy storage (CAES) systems. The assessment is based on (1) detailed analyses of the market potential of utility storage technologies, (2) interviews with representatives of key participants in the CAES market, and (3) a decision analysis synthesizing much of the information about market and technology status. The results indicate a large potential market for CAES systems if the overall business environment for utilities improves. In addition, it appears that EPRI can have a valuable incremental impact in ensuring that utilities realize the potential of CAES by (1) continuing an aggressive information dissemination and technology transfer program, (2) working to ensure the success of the first United States CAES installation at Soyland Power Cooperative, (3) developing planning methods to allow utilities to evaluate CAES and other storage options more effectively and more realistically, and (4) supporting R and D to resolve residual uncertainties in first-generation CAES cost and performance characteristics. Previously announced in STAR as N83-25121
Boyd, D. W.; Buckley, O. E.; Clark, C. E.
1982-12-01
This report describes an assessment of potential roles that EPRI might take to facilitate the commercial acceptance of compressed air energy storage (CAES) systems. The assessment is based on (1) detailed analyses of the market potential of utility storage technologies, (2) interviews with representatives of key participants in the CAES market, and (3) a decision analysis synthesizing much of the information about market and technology status. The results indicate a large potential market for CAES systems if the overall business environment for utilities improves. In addition, it appears that EPRI can have a valuable incremental impact in ensuring that utilities realize the potential of CAES by (1) continuing an aggressive information dissemination and technology transfer program, (2) working to ensure the success of the first United States CAES installation at Soyland Power Cooperative, (3) developing planning methods to allow utilities to evaluate CAES and other storage options more effectively and more realistically, and (4) supporting R and D to resolve residual uncertainties in first-generation CAES cost and performance characteristics.
Single-mode fiber laser based on core-cladding mode conversion.
Suzuki, Shigeru; Schülzgen, Axel; Peyghambarian, N
2008-02-15
A single-mode fiber laser based on an intracavity core-cladding mode conversion is demonstrated. The fiber laser consists of an Er-doped active fiber and two fiber Bragg gratings. One Bragg grating is a core-cladding mode converter, and the other Bragg grating is a narrowband high reflector that selects the lasing wavelength. Coupling a single core mode and a single cladding mode by the grating mode converter, the laser operates as a hybrid single-mode laser. This approach for designing a laser cavity provides a much larger mode area than conventional large-mode-area step-index fibers.
Effect of modes interaction on the resistive wall mode stability
International Nuclear Information System (INIS)
Chen Longxi; Wu Bin
2013-01-01
Effects of modes interaction on the resistive wall mode (RWM) stability are studied. When considering the modes interaction effects, the linear growth rate of the most unstable (3, 1) mode decreases. After linear evolution, the RWM saturates at the nonlinear phase. The saturation can be attributed to flux piling up on the resistive wall. When some modes exist, the (3, 1) mode saturates at lower level compared with single mode evolution. Meanwhile, the magnetic energy of the (5, 2) mode increases correspondingly, but the magnetic energy saturation level of the (2, 1) mode changes weakly. (authors)
Ding, Edwin; Lefrancois, Simon; Kutz, Jose Nathan; Wise, Frank W
2011-01-01
The mode-locking of dissipative soliton fiber lasers using large mode area fiber supporting multiple transverse modes is studied experimentally and theoretically. The averaged mode-locking dynamics in a multi-mode fiber are studied using a distributed model. The co-propagation of multiple transverse modes is governed by a system of coupled Ginzburg-Landau equations. Simulations show that stable and robust mode-locked pulses can be produced. However, the mode-locking can be destabilized by excessive higher-order mode content. Experiments using large core step-index fiber, photonic crystal fiber, and chirally-coupled core fiber show that mode-locking can be significantly disturbed in the presence of higher-order modes, resulting in lower maximum single-pulse energies. In practice, spatial mode content must be carefully controlled to achieve full pulse energy scaling. This paper demonstrates that mode-locking performance is very sensitive to the presence of multiple waveguide modes when compared to systems such as amplifiers and continuous-wave lasers.
DEFF Research Database (Denmark)
Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede
2013-01-01
-connected PV inverters may be severely affected in different operation modes. In this paper, a detailed analysis is conducted to reveal the relationship between the harmonics level with the power factor and the current level in the PV systems. A current control solution which employs an Internal Model...... Principle (IMP) is proposed to suppress the harmonic currents injected into the grid. Experiments are carried out to verify the analysis and the performance of the proposed control method. It is demonstrated that the proposed method presents an effective solution to harmonics suppression for single......-phase grid-connected PV systems in different operation modes. Especially, it can remove higher order harmonics effectively leading to a better power quality compared to the Proportional plus Multi-Resonant Controller, and it has less computational burden....
Socorro, A. B.; Corres, J. M.; Del Villar, I.; Matias, I. R.; Arregui, F. J.
2014-05-01
This work presents the development and test of an anti-gliadin antibodies biosensor based on lossy mode resonances (LMRs) to detect celiac disease. Several polyelectrolites were used to perform layer-by-layer assembly processes in order to generate the LMR and to fabricate a gliadin-embedded thin-film. The LMR shifted 20 nm when immersed in a 5 ppm anti-gliadin antibodies-PBS solution, what makes this bioprobe suitable for detecting celiac disease. This is the first time, to our knowledge, that LMRs are used to detect celiac disease and these results suppose promising prospects on the use of such phenomena as biological detectors.
International Nuclear Information System (INIS)
Kyung-shick Min; Byung-hun Lee
1987-01-01
Computer-aided-engineering (CAE) is an essential tool for modern nuclear power plant engineering. It greatly varies in definition, application, and technology from project to project and company to company. Despite the fast growing technologies and applications of CAE, its complexty and variety have thrown aonther puzzle to management of a nuclear project. Without due consideration of an integrated CAE system in early planning stage, the overall efficiency of a nuclear project would slow down due to the inefficiency in data flow. In this paper, practices and perspectives of CAE appliation are discussed under the Korea Power Engineering Company (KOPEC) philosophy in CAE approach. (author)
DEFF Research Database (Denmark)
Berendt, Martin Ole; Grüne-Nielsen, Lars; Soccolich, C.F.
1998-01-01
to reduce this problem. None of these designs seems to give complete solutions. In particular, the otherwise promising depressed cladding design gives a pronounced coupling to one LP01 mode, this has been referred to as a Ghost grating. To find the modes of the fiber we have established a numerical mode......UV-written Bragg gratings find wide spread use as wavelength selective components. In reflection high extinction ratios are routinely obtained. However, coupling to cladding modes gives excess loss on the short wavelength side of the main reflection. Different fiber-designs have been proposed......-solver based on the staircase-approximation method. The Bragg grating causes coupling between the fundamental LP01 mode and higher order LP1p modes that satisfy phase-matching. The coupling strength is determined by the overlap integral of the LP01, the LP1p mode, and the UV-induced index perturbation. For LP0...
Impedance Eduction in Large Ducts Containing Higher-Order Modes and Grazing Flow
Watson, Willie R.; Jones, Michael G.
2017-01-01
Impedance eduction test data are acquired in ducts with small and large cross-sectional areas at the NASA Langley Research Center. An improved data acquisition system in the large duct has resulted in increased control of the acoustic energy in source modes and more accurate resolution of higher-order duct modes compared to previous tests. Two impedance eduction methods that take advantage of the improved data acquisition to educe the liner impedance in grazing flow are presented. One method measures the axial propagation constant of a dominant mode in the liner test section (by implementing the Kumarsean and Tufts algorithm) and educes the impedance from an exact analytical expression. The second method solves numerically the convected Helmholtz equation and minimizes an objective function to obtain the liner impedance. The two methods are tested first on data synthesized from an exact mode solution and then on measured data. Results show that when the methods are applied to data acquired in the larger duct with a dominant higher-order mode, the same impedance spectra are educed as that obtained in the small duct where only the plane wave mode propagates. This result holds for each higher-order mode in the large duct provided that the higher-order mode is sufficiently attenuated by the liner.
ATM security via "Stargate" solution
Hensley, Katrina; Ludden, Fredrick
1999-01-01
Approved for public release, distribution unlimited. In today's world of integrating voice, video and data into a single network, Asynchronous Transfer Mode (ATM) networks have become prevalent in the Department of Defense. The Department of Defense's critical data will have to pass through public networks, which causes concern for security. This study presents an efficient solution aimed at authenticating communications over public ATM networks. The authenticating device, Stargate, utiliz...
The Combinatorial Multi-Mode Resource Constrained Multi-Project Scheduling Problem
Directory of Open Access Journals (Sweden)
Denis Pinha
2016-11-01
Full Text Available This paper presents the formulation and solution of the Combinatorial Multi-Mode Resource Constrained Multi-Project Scheduling Problem. The focus of the proposed method is not on finding a single optimal solution, instead on presenting multiple feasible solutions, with cost and duration information to the project manager. The motivation for developing such an approach is due in part to practical situations where the definition of optimal changes on a regular basis. The proposed approach empowers the project manager to determine what is optimal, on a given day, under the current constraints, such as, change of priorities, lack of skilled worker. The proposed method utilizes a simulation approach to determine feasible solutions, under the current constraints. Resources can be non-consumable, consumable, or doubly constrained. The paper also presents a real-life case study dealing with scheduling of ship repair activities.
Analytical solution for a linearly graded-index-profile planar waveguide.
Touam, T; Yergeau, F
1993-01-20
An analytical solution is presented for the TE modes of a planar waveguide structure comprising a high-index guiding layer and a buried layer with a profile such that the square of the index varies linearly and matches the substrate and high-index guiding layer. The electric-field profiles and the dispersion relation are obtained and discussed, and a solution by the WKB method is compared.
DEM Solutions Develops Answers to Modeling Lunar Dust and Regolith
Dunn, Carol Anne; Calle, Carlos; LaRoche, Richard D.
2010-01-01
With the proposed return to the Moon, scientists like NASA-KSC's Dr. Calle are concerned for a number of reasons. We will be staying longer on the planet's surface, future missions may include dust-raising activities, such as excavation and handling of lunar soil and rock, and we will be sending robotic instruments to do much of the work for us. Understanding more about the chemical and physical properties of lunar dust, how dust particles interact with each other and with equipment surfaces and the role of static electricity build-up on dust particles in the low-humidity lunar environment is imperative to the development of technologies for removing and preventing dust accumulation, and successfully handling lunar regolith. Dr. Calle is currently working on the problems of the electrostatic phenomena of granular and bulk materials as they apply to planetary surfaces, particularly to those of Mars and the Moon, and is heavily involved in developing instrumentation for future planetary missions. With this end in view, the NASA Kennedy Space Center's Innovative Partnerships Program Office partnered with OEM Solutions, Inc. OEM Solutions is a global leader in particle dynamics simulation software, providing custom solutions for use in tackling tough design and process problems related to bulk solids handling. Customers in industries such as pharmaceutical, chemical, mineral, and materials processing as well as oil and gas production, agricultural and construction, and geo-technical engineering use OEM Solutions' EDEM(TradeMark) software to improve the design and operation of their equipment while reducing development costs, time-to-market and operational risk. EDEM is the world's first general-purpose computer-aided engineering (CAE) tool to use state-of-the-art discrete element modeling technology for the simulation and analysis of particle handling and manufacturing operations. With EDEM you'can quickly and easily create a parameterized model of your granular solids
Bushes of vibrational modes for Fermi-Pasta-Ulam chains
Chechin, G. M.; Novikova, N. V.; Abramenko, A. A.
2002-06-01
Some exact solutions and multimode invariant submanifolds were found for the Fermi-Pasta-Ulam (FPU)- β model by Poggi and Ruffo [Physica D 103 (1997) 251]. In the present paper we demonstrate how results of such a type can be obtained for an arbitraryN-particle chain with periodic boundary conditions with the aid of our group-theoretical approach [Physica D 117 (1998) 43] based on the concept of bushes of normal modes in mechanical systems with discrete symmetry. The integro-differential equation describing the FPU- α dynamics in the modal space is derived. The loss of stability of the bushes of modes for the FPU- α model, in particular, for the limiting case N→∞ for the dynamical regime with displacement pattern having period twice the lattice spacing ( π-mode) is studied. Our results for the FPU- α chain are compared with those by Poggi and Ruffo for the FPU- β chain.
Two-fluid hydrodynamic modes in a trapped superfluid gas
International Nuclear Information System (INIS)
Taylor, E.; Griffin, A.
2005-01-01
In the collisional region at finite temperatures, the collective modes of superfluids are described by the Landau two-fluid hydrodynamic equations. This region can now be probed over the entire BCS-Bose-Einstein-condensate crossover in trapped Fermi superfluids with a Feshbach resonance, including the unitarity region. Building on the approach initiated by Zaremba, Nikuni, and Griffin in 1999 for trapped atomic Bose gases, we present a variational formulation of two-fluid hydrodynamic collective modes based on the work of Zilsel in 1950 developed for superfluid helium. Assuming a simple variational Ansatz for the superfluid and normal fluid velocities, the frequencies of the hydrodynamic modes are given by solutions of coupled algebraic equations, with constants only involving spatial integrals over various equilibrium thermodynamic derivatives. This variational approach is both simpler and more physical than a direct attempt to solve the Landau two-fluid differential equations. Our two-fluid results are shown to reduce to those of Pitaevskii and Stringari for a pure superfluid at T=0
Mukaitani, Ichiroh; Hayashi, Koji; Shimoura, Ichiro; Takemasa, Arihiko; Takahashi, Isamu; Tsubakino, Harushige
software " Solid Works" and computer aided engineering (CAE) software " ANSYS" with corrosion elongation transformed into thermal elongation. We established a current collector corrosion elongation forecast and found that the microstructure controlled the Pb-Ca-Sn alloy; thus newly designed VRLA batteries (MU-series [A. Takemasa, I. Mukaitani, Y. Yoshiyama, K. Fukui, T. Sakamoto, T. Kuwano, M. Fukuda, H. Misaki, K. Uwatari, Shin-Kobe Technical Report 9 (1999) 11] for telecommunication and LL-series [H. Takabayashi, T. Shibahara, Y. Mastuda, K. Fukui, S. Hazui, Y. Matsumura, S. Kondo, Shin-Kobe Tech. Rep. 11 (2001) 35] for electric energy storage) which are lightweight and have long life are introduced here.
Saddle point solutions in Yang-Mills-dilaton theory
International Nuclear Information System (INIS)
Bizon, P.
1992-01-01
The coupling of a dilaton to the SU(2)-Yang-Mills field leads to interesting non-perturbative static spherically symmetric solutions which are studied by mixed analytical and numerical methods. In the abelian sector of the theory there are finite-energy magnetic and electric monopole solutions which saturate the Bogomol'nyi bound. In the nonabelian sector there exist a countable family of globally regular solutions which are purely magnetic but have zero Yang-Mills magnetic charge. Their discrete spectrum of energies is bounded from above by the energy of the abelian magnetic monopole with unit magnetic charge. The stability analysis demonstrates that the solutions are saddle points of the energy functional with increasing number of unstable modes. The existence and instability of these solutions are 'explained' by the Morse-theory argument recently proposed by Sudarsky and Wald. (author)
Stability analysis of internal ideal modes in low-shear tokamaks
International Nuclear Information System (INIS)
Wahlberg, C.; Graves, J. P.
2007-01-01
The stability of internal, ideal modes in tokamaks with low magnetic shear in the plasma core is analyzed. For equilibria with large aspect ratio, a parabolic pressure profile and a flat q profile in the core, an exact solution of the ideal magnetohydrodynamic (MHD) stability equations is found. The solution includes the eigenfunctions and the complete spectra of two distinctly different MHD phenomena: A family of fast-growing, Mercier-unstable global eigenmodes localized in a low-shear region with q 1 in the core. In the latter case the solution in addition includes one unstable eigenmode, if beta is larger than a critical value depending on the width of the low-shear region and on the q-profile in the edge region
Radiative type-III ELMy H-mode in all-tungsten ASDEX Upgrade
Rapp, J.; Kallenbach, A.; Neu, R.; Eich, T.; Fischer, R.; Herrmann, A.; Potzel, S.; van Rooij, G. J.; Zielinski, J. J.; ASDEX Upgrade team,
2012-01-01
The type-III ELMy H-mode might be the solution for an integrated ITER operation scenario fulfilling the fusion power amplification factor (output fusion power to input heating power) of Q = 10 with simultaneous acceptable steady-state and transient power loads to the plasma-facing components. This
Pescaru, A.; Oanta, E.; Axinte, T.; Dascalescu, A.-D.
2015-11-01
Computer aided engineering is based on models of the phenomena which are expressed as algorithms. The implementations of the algorithms are usually software applications which are processing a large volume of numerical data, regardless the size of the input data. In this way, the finite element method applications used to have an input data generator which was creating the entire volume of geometrical data, starting from the initial geometrical information and the parameters stored in the input data file. Moreover, there were several data processing stages, such as: renumbering of the nodes meant to minimize the size of the band length of the system of equations to be solved, computation of the equivalent nodal forces, computation of the element stiffness matrix, assemblation of system of equations, solving the system of equations, computation of the secondary variables. The modern software application use pre-processing and post-processing programs to easily handle the information. Beside this example, CAE applications use various stages of complex computation, being very interesting the accuracy of the final results. Along time, the development of CAE applications was a constant concern of the authors and the accuracy of the results was a very important target. The paper presents the various computing techniques which were imagined and implemented in the resulting applications: finite element method programs, finite difference element method programs, applied general numerical methods applications, data generators, graphical applications, experimental data reduction programs. In this context, the use of the extended precision data types was one of the solutions, the limitations being imposed by the size of the memory which may be allocated. To avoid the memory-related problems the data was stored in files. To minimize the execution time, part of the file was accessed using the dynamic memory allocation facilities. One of the most important consequences of the
Efficiency of Compressed Air Energy Storage
DEFF Research Database (Denmark)
Elmegaard, Brian; Brix, Wiebke
2011-01-01
The simplest type of a Compressed Air Energy Storage (CAES) facility would be an adiabatic process consisting only of a compressor, a storage and a turbine, compressing air into a container when storing and expanding when producing. This type of CAES would be adiabatic and would if the machines...... were reversible have a storage efficiency of 100%. However, due to the specific capacity of the storage and the construction materials the air is cooled during and after compression in practice, making the CAES process diabatic. The cooling involves exergy losses and thus lowers the efficiency...... of the storage significantly. The efficiency of CAES as an electricity storage may be defined in several ways, we discuss these and find that the exergetic efficiency of compression, storage and production together determine the efficiency of CAES. In the paper we find that the efficiency of the practical CAES...
Attention Contributes to Arithmetic Deficits in New-Onset Childhood Absence Epilepsy.
Cheng, Dazhi; Yan, Xiuxian; Gao, Zhijie; Xu, Keming; Chen, Qian
2017-01-01
Neuropsychological studies indicate that new-onset childhood absence epilepsy (CAE) is associated with deficits in attention and executive functioning. However, the contribution of these deficits to impaired academic performance remains unclear. We aimed to examine whether attention and executive functioning deficits account for the academic difficulties prevalent in patients with new-onset CAE. We analyzed cognitive performance in several domains, including language, mathematics, psychomotor speed, spatial ability, memory, general intelligence, attention, and executive functioning, in 35 children with new-onset CAE and 33 control participants. Patients with new-onset CAE exhibited deficits in mathematics, general intelligence, attention, and executive functioning. Furthermore, attention deficits, as measured by a visual tracing task, accounted for impaired arithmetic performance in the new-onset CAE group. Therefore, attention deficits, rather than impaired general intelligence or executive functioning, may be responsible for arithmetic performance deficits in patients with new-onset CAE.
Mixed-mode loading of the structural elements with defect
Directory of Open Access Journals (Sweden)
Larisa V. Stepanova
2015-06-01
Full Text Available In the article the problem of determining the stress-strain state near the mixed-mode crack tip in a power-law material under plane stress conditions is considered. The eigenfunction method is used for the mixed-mode crack tip problem. It is shown that the eigenfunction expansion method results in the nonlinear eigenvalue problem. The numeric solution of the nonlinear eigenvalue problem formulated is obtained. The power of the distance from the crack tip is the eigenvalue of the nonlinear eigenvalue problem considered whereas the angular distributions of the stress components are the eigenfunctions. The new eigenvalues different from the eigenvalues of the Hutchinson–Rice–Rosengren are found. It is shown that the new asymptotic solution can be interpreted as the self-similar intermediate asymptotics of the stress field in the vicinity of the crack tip at distances which are very small compared to the crack length or the size of the specimen and at distances which are large compared to the length of the completely damaged zone. The developed method allows us to construct the geometry of the completely damaged zone in vicinity of the crack tip.
Li, Donglan
2015-01-01
This paper, as an attempt to find a solution to the problem of "Identity Crisis" brought about by the traditional spoon-feeding Education Mode, explores to construct a new mode of vocal music teaching characterized by an interaction on an equal and democratic footing between learners and the teacher in light of Habermas' Communicative…
Nakajima, Kazuki; Kinoshita, Mitsuhiro; Oda, Yasuo; Masuko, Takashi; Kaku, Hanae; Shibuya, Naoto; Kakehi, Kazuaki
2004-09-01
We developed capillary affinity electrophoresis (CAE) to analyze the molecular interaction between carbohydrate chains and proteins in solution state. A mixture of oligosaccharides derived from a glycoprotein was labeled with 8-aminopyrene-1,3,6-trisulfonate (APTS), and used as glycan library without isolation. Interaction of a carbohydrate-binding protein with each oligosaccharide in the mixture could be simultaneously observed, and relative affinities of oligosaccharides toward the protein were accurately determined. In this study, we applied CAE to detect the presence of lectins in some plants (Japanese elderberry bark and tulip bulb). In the crude extract of the elderberry bark, binding activity toward sialo-carbohydrate chains could be easily detected. We also examined the presence of lectins in the crude extract of tulip bulbs and determined the detailed carbohydrate-binding specificity of Tulipa gesneriana agglutinin (TGA), one of the lectins from tulip bulbs. Kinetic studies demonstrated that TGA showed novel carbohydrate-binding specificity and preferentially recognized triantennary oligosaccharides with Gal residues at nonreducing termini and a Fuc residue linked through alpha(1-6) linkage at chitobiose portion of the reducing termini but not tetraantennary carbohydrates. The results described here indicate that CAE will be a valuable method for both screening of lectins in natural sources and determination of their detailed carbohydrate-binding specificities.
Virtual X-ray imaging techniques in an immersive casting simulation environment
International Nuclear Information System (INIS)
Li, Ning; Kim, Sung-Hee; Suh, Ji-Hyun; Cho, Sang-Hyun; Choi, Jung-Gil; Kim, Myoung-Hee
2007-01-01
A computer code was developed to simulate radiograph of complex casting products in a CAVE TM -like environment. The simulation is based on the deterministic algorithms and ray tracing techniques. The aim of this study is to examine CAD/CAE/CAM models at the design stage, to optimize the design and inspect predicted defective regions with fast speed, good accuracy and small numerical expense. The present work discusses the algorithms for the radiography simulation of CAD/CAM model and proposes algorithmic solutions adapted from ray-box intersection algorithm and octree data structure specifically for radiographic simulation of CAE model. The stereoscopic visualization of full-size of product in the immersive casting simulation environment as well as the virtual X-ray images of castings provides an effective tool for design and evaluation of foundry processes by engineers and metallurgists
Linear stability analysis of detonations via numerical computation and dynamic mode decomposition
Kabanov, Dmitry I.
2017-12-08
We introduce a new method to investigate linear stability of gaseous detonations that is based on an accurate shock-fitting numerical integration of the linearized reactive Euler equations with a subsequent analysis of the computed solution via the dynamic mode decomposition. The method is applied to the detonation models based on both the standard one-step Arrhenius kinetics and two-step exothermic-endothermic reaction kinetics. Stability spectra for all cases are computed and analyzed. The new approach is shown to be a viable alternative to the traditional normal-mode analysis used in detonation theory.
Linear stability analysis of detonations via numerical computation and dynamic mode decomposition
Kabanov, Dmitry; Kasimov, Aslan R.
2018-01-01
We introduce a new method to investigate linear stability of gaseous detonations that is based on an accurate shock-fitting numerical integration of the linearized reactive Euler equations with a subsequent analysis of the computed solution via the dynamic mode decomposition. The method is applied to the detonation models based on both the standard one-step Arrhenius kinetics and two-step exothermic-endothermic reaction kinetics. Stability spectra for all cases are computed and analyzed. The new approach is shown to be a viable alternative to the traditional normal-mode analysis used in detonation theory.
Linear stability analysis of detonations via numerical computation and dynamic mode decomposition
Kabanov, Dmitry
2018-03-20
We introduce a new method to investigate linear stability of gaseous detonations that is based on an accurate shock-fitting numerical integration of the linearized reactive Euler equations with a subsequent analysis of the computed solution via the dynamic mode decomposition. The method is applied to the detonation models based on both the standard one-step Arrhenius kinetics and two-step exothermic-endothermic reaction kinetics. Stability spectra for all cases are computed and analyzed. The new approach is shown to be a viable alternative to the traditional normal-mode analysis used in detonation theory.
A p-coumaroyl esterase from Rhizoctonia solani with a pronounced chlorogenic acid esterase activity.
Nieter, Annabel; Kelle, Sebastian; Linke, Diana; Berger, Ralf G
2017-07-25
Extracellular esterase activity was detected in submerged cultures of Rhizoctonia solani grown in the presence of sugar beet pectin or Tween 80. Putative type B feruloyl esterase (FAE) coding sequences found in the genome data of the basidiomycete were heterologously expressed in Pichia pastoris. Recombinant enzyme production on the 5-L bioreactor scale (Rs pCAE: 3245UL -1 ) exceeded the productivity of the wild type strain by a factor of 800. Based on substrate specificity profiling, the purified recombinant Rs pCAE was classified as a p-coumaroyl esterase (pCAE) with a pronounced chlorogenic acid esterase side activity. The Rs pCAE was also active on methyl cinnamate, caffeate and ferulate and on feruloylated saccharides. The unprecedented substrate profile of Rs pCAE together with the lack of sequence similarity to known FAEs or pCAEs suggested that the Rs pCAE represents a new type of enzyme. Hydroxycinnamic acids were released from agro-industrial side-streams, such as destarched wheat bran (DSWB), sugar beet pectin (SBP) and coffee pulp (CP). Overnight incubation of coffee pulp with the Rs pCAE resulted in the efficient release of p-coumaric (100%), caffeic (100%) and ferulic acid (85%) indicating possible applications for the valorization of food processing wastes and for the enhanced degradation of lignified biomass. Copyright © 2017 Elsevier B.V. All rights reserved.
Bieniek, M. S.; Santos, D. F. N.; Almeida, P. G. C.; Benilov, M. S.
2018-04-01
General scenarios of transitions between different spot patterns on electrodes of DC gas discharges and their relation to bifurcations of steady-state solutions are analyzed. In the case of cathodes of arc discharges, it is shown that any transition between different modes of current transfer is related to a bifurcation of steady-state solutions. In particular, transitions between diffuse and spot modes on axially symmetric cathodes, frequently observed in the experiment, represent an indication of the presence of pitchfork or fold bifurcations of steady-state solutions. Experimental observations of transitions on cathodes of DC glow microdischarges are analyzed and those potentially related to bifurcations of steady-state solutions are identified. The relevant bifurcations are investigated numerically and the computed patterns are found to conform to those observed in the course of the corresponding transitions in the experiment.
Effect of nonlinear energy transport on neoclassical tearing mode stability in tokamak plasmas
Fitzpatrick, Richard
2017-05-01
An investigation is made into the effect of the reduction in anomalous perpendicular electron heat transport inside the separatrix of a magnetic island chain associated with a neoclassical tearing mode in a tokamak plasma, due to the flattening of the electron temperature profile in this region, on the overall stability of the mode. The onset of the neoclassical tearing mode is governed by the ratio of the divergences of the parallel and perpendicular electron heat fluxes in the vicinity of the island chain. By increasing the degree of transport reduction, the onset of the mode, as the divergence ratio is gradually increased, can be made more and more abrupt. Eventually, when the degree of transport reduction passes a certain critical value, the onset of the neoclassical tearing mode becomes discontinuous. In other words, when some critical value of the divergence ratio is reached, there is a sudden bifurcation to a branch of neoclassical tearing mode solutions. Moreover, once this bifurcation has been triggered, the divergence ratio must be reduced by a substantial factor to trigger the inverse bifurcation.
Directory of Open Access Journals (Sweden)
Predrag Pejovic
2013-12-01
Full Text Available Application of a single phase rectifier as an example in teaching circuit modeling, normalization, operating modes of nonlinear circuits, and circuit analysis methods is proposed.The rectifier supplied from a voltage source by an inductive impedance is analyzed in the discontinuous as well as in the continuous conduction mode. Completely analytical solution for the continuous conduction mode is derived. Appropriate numerical methods are proposed to obtain the circuit waveforms in both of the operating modes, and to compute the performance parameters. Source code of the program that performs such computation is provided.
New diffusion-like solutions of one-speed transport equations in spherical geometry
International Nuclear Information System (INIS)
Sahni, D.C.
1988-01-01
Stationary, one-speed, spherically symmetric transport equations are considered in a conservative medium. Closed-form expressions are obtained for the angular flux ψ(r, μ) that yield a total flux varying as 1/r by using Sonine transforms. Properties of this solution are studied and it is shown that the solution can not be identified as a diffusion mode solution of the transport equation. Limitations of the Sonine transform technique are noted. (author)
Knotted solutions for linear and nonlinear theories: Electromagnetism and fluid dynamics
Directory of Open Access Journals (Sweden)
Daniel W.F. Alves
2017-10-01
Full Text Available We examine knotted solutions, the most simple of which is the “Hopfion”, from the point of view of relations between electromagnetism and ideal fluid dynamics. A map between fluid dynamics and electromagnetism works for initial conditions or for linear perturbations, allowing us to find new knotted fluid solutions. Knotted solutions are also found to be solutions of nonlinear generalizations of electromagnetism, and of quantum-corrected actions for electromagnetism coupled to other modes. For null configurations, electromagnetism can be described as a null pressureless fluid, for which we can find solutions from the knotted solutions of electromagnetism. We also map them to solutions of Euler's equations, obtained from a type of nonrelativistic reduction of the relativistic fluid equations.
McCollom, Brittany A; Collis, Jon M
2014-09-01
A normal mode solution to the ocean acoustic problem of the Pekeris waveguide with an elastic bottom using a Green's function formulation for a compressional wave point source is considered. Analytic solutions to these types of waveguide propagation problems are strongly dependent on the eigenvalues of the problem; these eigenvalues represent horizontal wavenumbers, corresponding to propagating modes of energy. The eigenvalues arise as singularities in the inverse Hankel transform integral and are specified by roots to a characteristic equation. These roots manifest themselves as poles in the inverse transform integral and can be both subtle and difficult to determine. Following methods previously developed [S. Ivansson et al., J. Sound Vib. 161 (1993)], a root finding routine has been implemented using the argument principle. Using the roots to the characteristic equation in the Green's function formulation, full-field solutions are calculated for scenarios where an acoustic source lies in either the water column or elastic half space. Solutions are benchmarked against laboratory data and existing numerical solutions.
Requirements for VICTORIA Class Fire Control System: Contact Management Function
2014-07-01
Requirements for VICTORIA Class Fire Control System Contact Management Function Tab Lamoureux CAE Integrated Enterprise Solutions...Contract Report DRDC-RDDC-2014-C190 July 2014 © Her Majesty the Queen in Right of Canada, as represented by the...i Abstract …….. The VICTORIA Class Submarines (VCS) are subject to a continuing program of technical upgrades. One such program is
Synchrony-induced modes of oscillation of a neural field model
Esnaola-Acebes, Jose M.; Roxin, Alex; Avitabile, Daniele; Montbrió, Ernest
2017-11-01
We investigate the modes of oscillation of heterogeneous ring networks of quadratic integrate-and-fire (QIF) neurons with nonlocal, space-dependent coupling. Perturbations of the equilibrium state with a particular wave number produce transient standing waves with a specific temporal frequency, analogously to those in a tense string. In the neuronal network, the equilibrium corresponds to a spatially homogeneous, asynchronous state. Perturbations of this state excite the network's oscillatory modes, which reflect the interplay of episodes of synchronous spiking with the excitatory-inhibitory spatial interactions. In the thermodynamic limit, an exact low-dimensional neural field model describing the macroscopic dynamics of the network is derived. This allows us to obtain formulas for the Turing eigenvalues of the spatially homogeneous state and hence to obtain its stability boundary. We find that the frequency of each Turing mode depends on the corresponding Fourier coefficient of the synaptic pattern of connectivity. The decay rate instead is identical for all oscillation modes as a consequence of the heterogeneity-induced desynchronization of the neurons. Finally, we numerically compute the spectrum of spatially inhomogeneous solutions branching from the Turing bifurcation, showing that similar oscillatory modes operate in neural bump states and are maintained away from onset.
Forward osmosis for oily wastewater reclamation: Multi-charged oxalic acid complexes as draw solutes
Ge, Qingchun; Amy, Gary L.; Chung, Neal Tai-Shung
2017-01-01
Cl and other recently synthesized draw solutes, the OA complexes show superior FO performance in terms of high water fluxes up to 27.5 and 89.1 LMH under the respective FO and PRO (pressure retarded osmosis) modes, both with negligible reverse solute fluxes
International Nuclear Information System (INIS)
Ayub, M; Tiwana, M H; Mann, A B
2010-01-01
In this study, we analyzed the diffraction of the acoustic dominant mode in a parallel-plate trifurcated waveguide with normal impedance boundary conditions in the case where surface impedances of the upper and lower infinite plates are different from each other. The acoustic dominant mode is incident in a soft/hard semi-infinite duct located symmetrically in the infinite lined duct. The solution of the boundary value problem using Fourier transform leads to two simultaneous modified Wiener-Hopf equations that are uncoupled using the pole removal technique. Two infinite sets of unknown coefficients are involved in the solution, which satisfy two infinite systems of linear algebraic equations. These systems are solved numerically. The new kernel functions are factorized. Some graphical results showing the influence of sundry parameters of interest on the reflection coefficient are presented.
Exotic distributions of rigid unit modes in the reciprocal spaces of framework aluminosilicates
International Nuclear Information System (INIS)
Dove, Martin T; Pryde, Alexandra K A; Heine, Volker; Hammonds, Kenton D
2007-01-01
Until recently it was assumed that rigid unit modes, defined as the zero-frequency solutions to the dynamical equations for an infinite framework of rigid corner-linked tetrahedra, were confined to a small set of normal modes with wavevectors on lines or planes of special symmetry in reciprocal space. Using a search method that explores the full three-dimensional reciprocal space, we have located rigid unit modes with wavevectors on exotic curved surfaces in reciprocal space for a range of silicate minerals. This has led to the realization that the crystal structures of these minerals contain rather more topological floppiness than had previously been realized. The origin of the exotic RUM surfaces remains to be understood
Slow relaxation mode in concentrated oil-in-water microemulsions consisting of repulsive droplets
Hattori, Y.; Ushiki, H.; Courbin, L.; Panizza, P.
2007-02-01
The present contribution reports on the observation of two diffusive relaxation modes in a concentrated microemulsion made of repulsive droplets. These two modes can be interpreted in the frame of Weissman’s and Pusey’s theoretical pioneering works. The fast mode is associated to the collective diffusion of droplets whereas the slow one corresponds to the relaxation of droplet concentration fluctuations associated with composition and/or size. We show that (i) repulsive interactions considerably slow down the latter and (ii) a generalized Stokes Einstein relationship between its coefficient of diffusion and the Newtonian viscosity of the solutions, similar to the Walden’s rule for electrolytes, holds for concentrated microemulsion systems made of repulsive droplets.
On fluttering modes for aircraft wing model in subsonic air flow.
Shubov, Marianna A
2014-12-08
The paper deals with unstable aeroelastic modes for aircraft wing model in subsonic, incompressible, inviscid air flow. In recent author's papers asymptotic, spectral and stability analysis of the model has been carried out. The model is governed by a system of two coupled integrodifferential equations and a two-parameter family of boundary conditions modelling action of self-straining actuators. The Laplace transform of the solution is given in terms of the 'generalized resolvent operator', which is a meromorphic operator-valued function of the spectral parameter λ, whose poles are called the aeroelastic modes. The residues at these poles are constructed from the corresponding mode shapes. The spectral characteristics of the model are asymptotically close to the ones of a simpler system, which is called the reduced model. For the reduced model, the following result is shown: for each value of subsonic speed, there exists a radius such that all aeroelastic modes located outside the circle of this radius centred at zero are stable. Unstable modes, whose number is always finite, can occur only inside this 'circle of instability'. Explicit estimate of the 'instability radius' in terms of model parameters is given.
A study of common-mode failures
International Nuclear Information System (INIS)
Edwards, G.T.; Watson, I.A.
1979-07-01
The purpose of the report is to investigate problems of the identification of the common failure mode (CFM) the reliability models used and the data required for their solution, particularly with regard to automatic protection systems for nuclear reactors. The available literature which was surveyed during the study is quoted and used as a basis for the main work of the study. The type of redundancy system under consideration is initially described and the types of CFM to which these systems are prone are identified before a general definition of the term 'common mode failure' is proposed. The definition and proposed classification system for CMF are based on the common cause of failure, so identifying the primary events. Defences against CFM are included and proposals for an overall strategy and detailed recommendations for design and operation are made. Common mode failures in US nuclear reactor systems, aircraft systems, and other sources including chemical plant systems are surveyed. The data indicates the importance of the human error problem in the causes of CMF in design, maintenance and operation. From a study of the collected data a redundancy sub-system model for CMF is developed which identifies three main categories of failure, non-recurrent engineering design errors, maintenance and test errors, and random interest events. The model proposed allows for the improvement in sub-system reliability where appropriate defences are applied. (author)
Dilute-solution Structure of Charged Arborescent Graft Polymer
International Nuclear Information System (INIS)
Yun, Seok; Briber, R.M.; Kee, R. Andrew; Gauthier, Mario
2006-01-01
The solutions of charged G1 arborescent polystyrene-graft-poly(2-vinylpyridine) copolymers in methanol-d4 and D 2 O were investigated over a dilute concentration range φ = 0.005-0.05 (φ: mass fraction) using small-angle neutron scattering (SANS). Upon addition of acid (HCl) arborescent graft polymers became charged and a peak appeared in SANS data. The interparticle distance (d exp ) calculated from a peak position corresponded to the expected value (d uni ) for a uniform particle distribution. This indicates the formation of liquid-like ordering due to long-range Coulombic repulsions. The smaller dielectric constant of methanol-d4 resulted in long-range electrostatic repulsions persisting to lower polymer concentration than in D 2 O. The slow mode scattering was observed by dynamic light scattering measurements for the same polymer solutions, indicating the presence of structural inhomogeneity in the solutions. Both the peak and slow mode disappeared by addition of NaCl or excess HCl into the solutions due to the screening of electrostatic interactions. The G1 polymer grafted with longer P2VP chains (M w ∼ 30,000 versus 5000 g mol) formed a gel on addition of HCl. This result reveals that molecular expansion is more significant for arborescent polymers with longer (M w ∼ 30,000) linear polyelectrolyte branches, resulting in gelation for φ > 0.01. Upon addition of NaCl or excess HCl a gel transformed back to a liquid resulted from the screening of electrostatic interactions.
Properties of solutions of Bloch-type equations for the paraelectric phase of KDP
Energy Technology Data Exchange (ETDEWEB)
Glowacki, M; Paszkiewicz, T [Wroclaw Univ. (Poland). Inst. Fyziki Teoretycznej
1979-10-01
Exact solutions for two sets of Bloch-like equations describing the paraelectric phase of the model of KDP were studied. The general properties of both solutions are the same. However, in numerical calculations they differ significantly. A modification of the decay law connected with the soft mode frequency fluctuations is considered.
Transverse multibunch modes for non-rigid bunches, including mode coupling
Energy Technology Data Exchange (ETDEWEB)
Berg, J S; Ruth, R D [Stanford Linear Accelerator Center, Menlo Park, CA (United States)
1996-08-01
A method for computing transverse multibunch growth rates and frequency shifts in rings, which has been described previously, is applied to the PEP-II B factory. The method allows multibunch modes with different internal-bunch oscillation modes to couple to one another, similar to single-bunch mode coupling. Including coupling between the multibunch modes gives effects similar to those seen in single-bunch mode coupling. These effects occur at currents that are lower than the single-bunch mode coupling threshold. (author)
International Nuclear Information System (INIS)
Itoh, Sanae.
1991-06-01
After the discovery of the H-mode in ASDEX ( a tokamak in Germany ) the transition between the L-mode ( Low confinement mode ) and H-mode ( High confinement mode ) has been observed in many tokamaks in the world. The H-mode has made a breakthrough in improving the plasma parameters and has been recognized to be a universal phenomena. Since its discovery, the extensive studies both in experiments and in theory have been made. The research on H-mode has been casting new problems of an anomalous transport across the magnetic surface. This series of lectures will provide a brief review of experiments for explaining H-mode and a model theory of H-mode transition based on the electric field bifurcation. If the time is available, a new theoretical model of the temporal evolution of the H-mode will be given. (author)
Analysis of current-bidirectional buck-boost based switch-mode audio amplifier
DEFF Research Database (Denmark)
Bolten Maizonave, Gert; Andersen, Michael A. E.; Kjærgaard, Claus
2011-01-01
The following studdy was carried out in order to assses quantitatively the performannce of the buck--boost converter whhen used as swiitch-mode audio amplifier. It comprises of, to beggin with, the de limitation of design criteria bassed on the state of-the-art solution, which is based...... in a differential mode buckbased amplifier with a boost converter as power supply. The averaged switch modelling of the differential mode current bidirectional topology is also used, in order to analyze the steady state and frequency-wise behaviour of this converter and parameterize it to meet the design criteria....... Next, several piecewise-linear siimulation resultss are shown with detail enough to emphasize the features of the converter. A simple prototype is implemented to verify the main predicted features. Presently no previous publicat ion could be found containing a thorough analysis of this topology...
Mode-to-mode energy transfers in convective patterns
Indian Academy of Sciences (India)
Abstract. We investigate the energy transfer between various Fourier modes in a low- dimensional model for thermal convection. We have used the formalism of mode-to-mode energy transfer rate in our calculation. The evolution equations derived using this scheme is the same as those derived using the hydrodynamical ...
Growing quasi-modes in dynamics of supersonic collapse
International Nuclear Information System (INIS)
Malkin, V.M.; Khudik, V.N.
1989-01-01
The hypothesis of globally stable self-similar regimes existence for supersonic Langmuir collapse plays a significant role in the attempts to construct a theory of strong Langmuir turbulence. A possibility for destruction of the stable against infinitely small perturbations self-similar regime of supersonic collapse by growing quasi-modes is demonstrated via the numerical solution of Cauchi problem for Zakharov equations. The quantitative criterion for the destruction of self-similar regimes is formulated. 9 refs.; 5 figs
Directory of Open Access Journals (Sweden)
Jianfa Gu
2017-01-01
Full Text Available The low-mode shell asymmetry and high-mode hot spot mixing appear to be the main reasons for the performance degradation of the National Ignition Facility (NIF implosion experiments. The effects of the mode coupling between low-mode P2 radiation flux asymmetry and intermediate-mode L = 24 capsule roughness on the implosion performance of ignition capsule are investigated by two-dimensional radiation hydrodynamic simulations. It is shown that the amplitudes of new modes generated by the mode coupling are in good agreement with the second-order mode coupling equation during the acceleration phase. The later flow field not only shows large areal density P2 asymmetry in the main fuel, but also generates large-amplitude spikes and bubbles. In the deceleration phase, the increasing mode coupling generates more new modes, and the perturbation spectrum on the hot spot boundary is mainly from the strong mode interactions rather than the initial perturbation conditions. The combination of the low-mode and high-mode perturbations breaks up the capsule shell, resulting in a significant reduction of the hot spot temperature and implosion performance.
Directory of Open Access Journals (Sweden)
R. Armas Cardona
2000-07-01
Full Text Available Los estudiantes de pregrado reciben entrenamiento y experiencia en el análisis de diseño del mundo real que encontrarán.La motivación que se despierta en los estudiantes de pregrado al enfrentarse a la solución de problemas de resistencia yrigidez reales o a la solución de sistemas mecánicos de formas complejas, es elevada. La diferenciación entre lasposibilidades de cálculo de modelos hechos a mano con los modelos desarrollados en computadora es grande y esto loentiende perfectamente el estudiante de pregrado quien reconoce la poderosa herramienta de trabajo y diseño. Aún más, elestudiante se siente competente y a la vanguardia de la técnica.Este trabajo consiste en mostrar los resultados obtenidos durante el proceso de ensañanza al aplicar un software deelementos finitos. Uno de los objetivos es alcanzar cierta estimación sobre el aprendizaje en las tareas de preprocesamiento,análisis y postprocesamiento ofrecidos por un sistema computacional de elementos finitos poco interactivo. En el curso deun semestre los estudiantes generan entidades paramétricas y no paramétricas, generan mallas de elementos finitos, ploteanresultados, animan el cuerpo modelado y otras tareas características.Palabras claves: Elementos Finitos, aprendizaje, enseñanza, estudio._____________________________________________________________________AbstractThe undergraduate students receive training and experience in the analysis of design of the real world. The motivation inthese students when they are facing the solution of real resistance and rigidity problems or the solution of mechanicalsystems of complex shape is very high. The difference between the calculation possibilities of hand made models with themodels developed in a computer is great and this is perfectly understood by the undergraduate students who recognizes thispowerful mean for work and design. Even more, the student feels competent and using advanced technique. This workshows the
Korsakova, S. V.; Romanova, E. A.; Velmuzhov, A. P.; Kotereva, T. V.; Sukhanov, M. V.; Shiryaev, V. S.
2017-04-01
Chalcogenide fibers are considered as a base for creation of a fiber-optical platform for the mid-IR evanescent wave spectroscopy. In this work, transmittance of a multimode fiber made of Ge26As17Se25Te32 glass, immersed into an aqueous acetone solution was measured in the range of wavelengths 5 - 9 microns at various concentrations of the solution. A theoretical approach based on electromagnetic theory of optical fibers has been applied for analysis of evanescent modes propagation in the fiber. Attenuation coefficients calculated for each HE1m evanescent mode increase with the mode radial order m. This effect can be used for optimisation of the fiber-optic sensing elements for the mid-IR spectroscopy.
Zero modes in de Sitter background
Energy Technology Data Exchange (ETDEWEB)
Einhorn, Martin B. [Kavli Institute for Theoretical Physics, University of California,Santa Barbara, CA 93106-4030 (United States); Jones, D.R. Timothy [Kavli Institute for Theoretical Physics, University of California,Santa Barbara, CA 93106-4030 (United States); Dept. of Mathematical Sciences, University of Liverpool,Liverpool L69 3BX (United Kingdom)
2017-03-28
There are five well-known zero modes among the fluctuations of the metric of de Sitter (dS) spacetime. For Euclidean signature, they can be associated with certain spherical harmonics on the S{sup 4} sphere, viz., the vector representation 5 of the global SO(5) isometry. They appear, for example, in the perturbative calculation of the on-shell effective action of dS space, as well as in models containing matter fields. These modes are shown to be associated with collective modes of S{sup 4} corresponding to certain coherent fluctuations. When dS space is embedded in flat five dimensions E{sup 5}, they may be seen as a legacy of translation of the center of the S{sup 4} sphere. Rigid translations of the S{sup 4}-sphere on E{sup 5} leave the classical action invariant but are unobservable displacements from the point of view of gravitational dynamics on S{sup 4}. Thus, unlike similar moduli, the center of the sphere is not promoted to a dynamical degree of freedom. As a result, these zero modes do not signify the possibility of physically realizable fluctuations or flat directions for the metric of dS space. They are not associated with Killing vectors on S{sup 4} but can be identified with certain non-isometric, conformal Killing forms that locally correspond to a rescaling of the volume element dV{sub 4}. We frame much of our discussion in the context of renormalizable gravity, but, to the extent that they only depend upon the global symmetry of the background, the conclusions should apply equally to the corresponding zero modes found in Einstein gravity. Although their existence has only been demonstrated at one-loop, we expect that these zero modes will be present to all orders in perturbation theory. They will occur for Lorentzian signature as well, so long as the hyperboloid H{sup 4} is locally stable, but there remain certain infrared issues that need to be clarified. We conjecture that they will appear in any gravitational theory having dS background as a
Analisys of Current-Bidirectional Buck-Boost Based Automotive Switch-Mode Audio Amplifier
DEFF Research Database (Denmark)
Bolten Maizonave, Gert; Andersen, Michael A. E.; Kjærgaard, Claus
2011-01-01
The following study was carried out in order to assess quantitatively the performance of the buck-boost converter when used as switch-mode audio amplifier. It comprises of, to begin with, the delimitation of design criteria based on the state-ofthe- art solution, which is based in a differential ...
PLC-based LP₁₁ mode rotator for mode-division multiplexing transmission.
Saitoh, Kunimasa; Uematsu, Takui; Hanzawa, Nobutomo; Ishizaka, Yuhei; Masumoto, Kohei; Sakamoto, Taiji; Matsui, Takashi; Tsujikawa, Kyozo; Yamamoto, Fumihiko
2014-08-11
A PLC-based LP11 mode rotator is proposed. The proposed mode rotator is composed of a waveguide with a trench that provides asymmetry of the waveguide. Numerical simulations show that converting LP11a (LP11b) mode to LP11b (LP11a) mode can be achieved with high conversion efficiency (more than 90%) and little polarization dependence over a wide wavelength range from 1450 nm to 1650 nm. In addition, we fabricate the proposed LP11 mode rotator using silica-based PLC. It is confirmed that the fabricated mode rotator can convert LP11a mode to LP11b mode over a wide wavelength range.
Li, Ruipeng
2012-09-04
A new way to investigate and control the growth of solution-cast thin films is presented. The combination of in situ quartz crystal microbalance measurements with dissipation capabilities (QCM-D) and in situ grazing-incidence wide-angle X-ray scattering (GIWAXS) in an environmental chamber provides unique quantitative insights into the time-evolution of the concentration of the solution, the onset of nucleation, and the mode of growth of the organic semiconductor under varied drying conditions. It is demonstrated that careful control over the kinetics of solution drying enhances carrier transport significantly by promoting phase transformation predominantly via heterogeneous nucleation and sustained surface growth of a highly lamellar structure at the solid-liquid interface at the expense of homogeneous nucleation. A new way to investigate and control the growth of drop-cast thin films is presented. The solution-processing of small-molecule thin films of TIPS-pentacene is investigated using time-resolved techniques to reveal the mechanisms of nucleation and growth leading to solid film formation. By tuning the drying speed of the solution, the balance between surface and bulk growth modes is altered, thereby controlling the lamellar formation and tuning the carrier mobility in organic field-effect transistors Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Effects of multiple modes interaction on the resistive wall mode instability
International Nuclear Information System (INIS)
Chen, Longxi; Lei, Wenqing; Ma, Zhiwei; Wu, Bin
2013-01-01
The effects of multiple modes interaction on the resistive wall mode (RWM) are studied in a slab geometry with and without plasma flow. The modes interaction can have a large effect on both the linear growth rate and the nonlinear saturation level of the RWM. We found that modes interaction can suppress the linear growth rate for the most unstable mode. The plasma flow can also help to control the growth of the RWM. The RWM can be stabilized completely by a plasma flow when considering the modes interaction. The effect of modes interaction on the RWM is stronger for the mode rational surface in the vacuum than that in the plasma. The modes interaction results in a substantially lowered saturation level for the most unstable RWM. (paper)
Analyzing x-ray hotspot images with Ince-Gaussian modes
Kruse, Michael; Field, John; Nora, Ryan; Benedetti, Robin; Khan, Shahab; Ma, Tammy; Peterson, Luc; Spears, Brian
2017-10-01
X-ray images at the National Ignition Facility (NIF) provide important metrics regarding the shape of the hotspot along a given line-of-sight. The 17% contour from peak brightness is usually used to infer the size of the hotspot as well as determine shape perturbations quantified through the Legendre coefficients P2 and P4. Unfortunately features that lie inside the contour such as those that could arise from tent or fill-tube perturbations are not easily captured. An analysis that takes into account the two-dimensional nature of the x-ray image is desirable. Ince-Gaussian modes (for short: Ince) offer such an analysis and could provide a new way to encode and understand the images recorded at NIF. The Ince modes are the solutions to the paraxial wave equation expressed in elliptical coordinates and thus form an orthonormal basis. Due to their elliptical nature they are suitable for decomposing images that have a non-zero P2 or P4 coefficient. We show that the Ince modes can be used to uncover structure that is missed by the contour analysis and how the modes aid in compressing images produced in large ensemble calculations. Finally a comparison is made to the Zernike modes which form an orthonormal basis on a circular disk. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-734741.
Ballooning modes or Fourier modes in a toroidal plasma?
International Nuclear Information System (INIS)
Connor, J.W.; Taylor, J.B.
1987-01-01
The relationship between two different descriptions of eigenmodes in a torus is investigated. In one the eigenmodes are similar to Fourier modes in a cylinder and are highly localized near a particular rational surface. In the other they are the so-called ballooning modes that extend over many rational surfaces. Using a model that represents both drift waves and resistive interchanges the transition from one of these structures to the other is investigated. In this simplified model the transition depends on a single parameter which embodies the competition between toroidal coupling of Fourier modes (which enhances ballooning) and variation in frequency of Fourier modes from one rational surface to another (which diminishes ballooning). As the coupling is increased each Fourier mode acquires a sideband on an adjacent rational surface and these sidebands then expand across the radius to form the extended mode described by the conventional ballooning mode approximation. This analysis shows that the ballooning approximation is appropriate for drift waves in a tokamak but not for resistive interchanges in a pinch. In the latter the conventional ballooning effect is negligible but they may nevertheless show a ballooning feature. This is localized near the same rational surface as the primary Fourier mode and so does not lead to a radially extended structure
Frontal and temporal volumes in Childhood Absence Epilepsy.
Caplan, Rochelle; Levitt, Jennifer; Siddarth, Prabha; Wu, Keng Nei; Gurbani, Suresh; Sankar, Raman; Shields, W Donald
2009-11-01
This study compared frontotemporal brain volumes in children with childhood absence epilepsy (CAE) to age- and gender-matched children without epilepsy. It also examined the association of these volumes with seizure, demographic, perinatal, intelligence quotient (IQ), and psychopathology variables. Twenty-six children with CAE, aged 7.5-11.8 years, and 37 children without epilepsy underwent brain magnetic resonance imaging (MRI) scans at 1.5 Tesla. Tissue was segmented, and total brain, frontal lobe, frontal parcellations, and temporal lobe volumes were computed. All children had IQ testing and structured psychiatric interviews. Parents provided seizure, perinatal, and behavioral information on each child. The CAE group had significantly smaller gray matter volumes of the left orbital frontal gyrus as well as both left and right temporal lobes compared to the age- and gender-matched children without epilepsy. In the CAE group these volumes were related to age, gender, ethnicity, and pregnancy complications but not to seizure, IQ, and psychopathology variables. In the group of children without epilepsy, however, the volumes were related to IQ. These findings suggest that CAE impacts brain development in regions implicated in behavior, cognition, and language. In addition to supporting the cortical focus theory of CAE, these findings also imply that CAE is not a benign disorder.
Du, Fengzhou; Li, Binghang; Yin, Ningbei; Cao, Yilin; Wang, Yongqian
2017-03-01
Knowing the volume of a graft is essential in repairing alveolar bone defects. This study investigates the 2 advanced preoperative volume measurement methods: three-dimensional (3D) printing and computer-aided engineering (CAE). Ten unilateral alveolar cleft patients were enrolled in this study. Their computed tomographic data were sent to 3D printing and CAE software. A simulated graft was used on the 3D-printed model, and the graft volume was measured by water displacement. The volume calculated by CAE software used mirror-reverses technique. The authors compared the actual volumes of the simulated grafts with the CAE software-derived volumes. The average volume of the simulated bone grafts by 3D-printed models was 1.52 mL, higher than the mean volume of 1.47 calculated by CAE software. The difference between the 2 volumes was from -0.18 to 0.42 mL. The paired Student t test showed no statistically significant difference between the volumes derived from the 2 methods. This study demonstrated that the mirror-reversed technique by CAE software is as accurate as the simulated operation on 3D-printed models in unilateral alveolar cleft patients. These findings further validate the use of 3D printing and CAE technique in alveolar defect repairing.
Energy Technology Data Exchange (ETDEWEB)
Fakhrian, K. [Universitaetsklinikum Bochum, Marienhospital Herne (Germany). Dept. of Radiation Oncology; Technische Univ. Muenchen, Klinikum Rechts der Isar (Germany). Dept. of Radiation Oncoalogy; Sauer, T.; Klemm, S.; Molls, M. [Technische Univ. Muenchen, Klinikum Rechts der Isar (Germany). Dept. of Radiation Oncoalogy; Dinkel, A. [Technische Univ. Muenchen, Klinikum Rechts der Isar (Germany). Dept. of Psychosomatic Medicine and Psychotherapy; Schuster, T. [Technische Univ. Muenchen, Klinikum Rechts der Isar (Germany). Inst. of Medical Statistics and Epidemiology; Geinitz, H. [Technische Univ. Muenchen, Klinikum Rechts der Isar (Germany). Dept. of Radiation Oncoalogy; Krankenhaus der Barmherzigen Schwestern, Linz (Austria). Dept. of Radiation Oncology
2013-06-15
Purpose: To report on chronic adverse events (CAE) and quality of life (QOL) after radiochemotherapy (RCT) in patients with anal cancer (AC). Patients and methods: Of 83 patients who had received RCT at our department between 1988 and 2011, 51 accepted the invitation to participate in this QOL study. CAE were evaluated using the Common Terminology Criteria for Adverse Events (CTCAE) v. 4.0 and QOL was assessed with the Functional Assessment of Cancer Therapy-Colorectal (FACT-C) questionnaire. Results: CAE could be evaluated in 49 patients. There was a tendency toward a higher rate of grade 3 CAE in female patients, i.e. 18 out of 37 (49 %) vs. 2 out of 12 (17 %) male patients (p = 0.089). The most common grade 3 CAE were dyspareunia and vaginal symptoms (itching, burning and dryness) in 35 and 22 % of female patients, respectively, followed by stool incontinence in 13 % of all patients (6 out of 49). Both FACT-C and CAE information were available for 42 patients, allowing evaluation of the impact of CAE on QOL. The median total FACT-C score was 110 (40-132) out of a possible maximum of 136. The absence of grade 3 CAE (115 vs. 94, p = 0.001); an interval of {>=} 67 months after the end of the treatment (111 vs. 107, p = 0.010), no stool incontinence vs. grade 3 stool incontinence (111 vs. 74, p = 0.009), higher education (114 vs. 107, p = 0.013) and no dyspareunia vs. grade 3 dyspareunia (116 vs. 93, p = 0.012) were significantly associated with a higher median FACT-C score. Conclusion: The majority of AC patients treated with RCT have acceptable overall QOL scores, which are comparable to those of the normal population. Patients with grade 3 CAE - particularly dyspareunia and fecal incontinence - have a poorer QOL compared to patients without CAE. In order to improve long-term QOL, future strategies might aim at a reduction in dose to the genitalia and more intensive patient support measures. (orig.)
International Nuclear Information System (INIS)
Fakhrian, K.; Technische Univ. Muenchen, Klinikum Rechts der Isar; Sauer, T.; Klemm, S.; Molls, M.; Dinkel, A.; Schuster, T.; Geinitz, H.; Krankenhaus der Barmherzigen Schwestern, Linz
2013-01-01
Purpose: To report on chronic adverse events (CAE) and quality of life (QOL) after radiochemotherapy (RCT) in patients with anal cancer (AC). Patients and methods: Of 83 patients who had received RCT at our department between 1988 and 2011, 51 accepted the invitation to participate in this QOL study. CAE were evaluated using the Common Terminology Criteria for Adverse Events (CTCAE) v. 4.0 and QOL was assessed with the Functional Assessment of Cancer Therapy-Colorectal (FACT-C) questionnaire. Results: CAE could be evaluated in 49 patients. There was a tendency toward a higher rate of grade 3 CAE in female patients, i.e. 18 out of 37 (49 %) vs. 2 out of 12 (17 %) male patients (p = 0.089). The most common grade 3 CAE were dyspareunia and vaginal symptoms (itching, burning and dryness) in 35 and 22 % of female patients, respectively, followed by stool incontinence in 13 % of all patients (6 out of 49). Both FACT-C and CAE information were available for 42 patients, allowing evaluation of the impact of CAE on QOL. The median total FACT-C score was 110 (40-132) out of a possible maximum of 136. The absence of grade 3 CAE (115 vs. 94, p = 0.001); an interval of ≥ 67 months after the end of the treatment (111 vs. 107, p = 0.010), no stool incontinence vs. grade 3 stool incontinence (111 vs. 74, p = 0.009), higher education (114 vs. 107, p = 0.013) and no dyspareunia vs. grade 3 dyspareunia (116 vs. 93, p = 0.012) were significantly associated with a higher median FACT-C score. Conclusion: The majority of AC patients treated with RCT have acceptable overall QOL scores, which are comparable to those of the normal population. Patients with grade 3 CAE - particularly dyspareunia and fecal incontinence - have a poorer QOL compared to patients without CAE. In order to improve long-term QOL, future strategies might aim at a reduction in dose to the genitalia and more intensive patient support measures. (orig.)
Single Mode Fiber Optic Transceiver Using Short Wavelength Active Devices In Long Wavelength Fiber
Gillham, Frederick J.; Campbell, Daniel R.; Corke, Michael; Stowe, David W.
1990-01-01
Presently, single mode optical fiber technology is being utilized in systems to supply telephone service to the subscriber. However, in an attempt to be competitive with copper based systems, there are many development programs underway to determine the most cost effective solution while still providing a service that will either satisfy or be upgradeable to satisfy the demands of the consumer for the next 10 to 20 years. One such approach is to combine low cost laser transmitters and silicon receivers, which have been developed for the "compact disc" industry, with fiber that operates in the single mode regime at 1300 nm. In this paper, an optical transceiver will be presented, consisting of a compact disc laser, a silicon detector and a single mode coupler at 1300 nm. A possible system layout is presented which operates at 780 nm bi-directionally for POTS and upgradeable to 1300 nm for video services. There are several important design criteria that have to be considered in the development of such a system which will be addressed. These include: 1. Optimization of coupled power from laser to fiber while maintaining stable launched conditions over a wide range of environmental conditions. 2. Consideration of the multimode operation of the 1300 nm single mode fiber while operating in the 780 nm wavelength region. 3. Development of a low cost pseudo-wavelength division multiplexer for 1300 nm single mode/780 nm multimode operation and a low cost dual mode 50/50, 780 nm splitter using 1300 nm fiber. Details will be given of the design criteria and solution in terms of optimized design. Results of the performance of several prototype devices will be given with indications of the merits of this approach and where further development effort should be applied.
Larsson, Anders; Gustavsson, Johan S.
The only active transverse mode in a truly single-mode VCSEL is the fundamental mode with a near Gaussian field distribution. A single-mode VCSEL produces a light beam of higher spectral purity, higher degree of coherence and lower divergence than a multimode VCSEL and the beam can be more precisely shaped and focused to a smaller spot. Such beam properties are required in many applications. In this chapter, after discussing applications of single-mode VCSELs, we introduce the basics of fields and modes in VCSELs and review designs implemented for single-mode emission from VCSELs in different materials and at different wavelengths. This includes VCSELs that are inherently single-mode as well as inherently multimode VCSELs where higher-order modes are suppressed by mode selective gain or loss. In each case we present the current state-of-the-art and discuss pros and cons. At the end, a specific example with experimental results is provided and, as a summary, the most promising designs based on current technologies are identified.
The locking and unlocking thresholds for tearing modes in a cylindrical tokamak
Energy Technology Data Exchange (ETDEWEB)
Huang, Wenlong [CAS Key Laboratory of Geospace Environment and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhu, Ping, E-mail: pzhu@ustc.edu.cn [CAS Key Laboratory of Geospace Environment and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)
2016-03-15
The locking and unlocking thresholds for tearing modes are in general different. In this work, the physics origin for this difference is illustrated from theory analysis, and a numerical procedure is developed to find both locking and unlocking thresholds. In particular, a new scaling law for the unlocking threshold that is valid in both weak and strong rotation regimes has been derived from the lowest amplitude of the RMP (resonant magnetic perturbation) allowed for the locked-mode solution. Above the unlocking threshold, the criterion for the phase-flip instability is extended to identify the entire locked-mode states. Two different regimes of the RMP amplitude in terms of the accessibility of the locked-mode states have been found. In the first regime, the locked-mode state may or may not be accessible depending on the initial conditions of an evolving island. In the second regime, the locked-mode state can always be reached regardless of the initial conditions of the tearing mode. The lowest RMP amplitude for the second regime is determined to be the mode-locking threshold. The different characteristics of the two regimes above the unlocking threshold reveal the underlying physics for the gap between the locking and unlocking thresholds and provide an explanation for the closely related and widely observed hysteresis phenomena in island evolution during the sweeping process of the RMP amplitude up and down across that threshold gap.
The Density Matrix for Single-mode Light after k-Photon Absorption
Voigt, H.; Bandilla, A.
In order to continue and generalize the studies of the density matrix of a light field undergoing k-photon absorption, in this paper we put the emphasis on the off-diagonal elements. The solution obtained earlier for the diagonal elements describing the photon statistics can be found as a special case but will not be discussed again. The general solution calculated by recursion shows an asymptotic behaviour if the initial photon number is sufficiently high. Only the initial phase information survives. Illustrating the solution we start with coherent light and a generalized coherent state.Translated AbstractDie Dichtematrix eines Lichtstrahls nach k-Photonen-Absorption aus einer ModeWir führen die Betrachtungen über das Verhalten der Dichtematrix eines Lichtfeldes nach k-Photonen-Absorption aus einer Mode verallgemeinernd weiter und konzentrieren uns auf die Nichtdiagonalelemente. Die im folgenden angegebene allgemeine Lösung, die durch Rekursion gefunden wurde, enthält die schon früher erhaltene, jedoch hier nicht weiter diskutierte Lösung für die Diagonalelemente als Spezialfall. Sie zeigt ferner, daß es einen asymptotischen Zustand gibt, der eine von der Ausgangsintensität unabhängige Information über die Ausgangsphase enthält. Zur Diskussion der Lösung werden verschiedene Anfangsbedingungen betrachtet, so z. B. kohärentes Licht und kohärentes Licht, das ein Medium mit nichtlinearem Brechungsindex durchlaufen hat (Kerr-Effekt).
Adur, Rohan; Du, Chunhui; Manuilov, Sergei A.; Wang, Hailong; Yang, Fengyuan; Pelekhov, Denis V.; Hammel, P. Chris
2015-05-01
The dipole field from a probe magnet can be used to localize a discrete spectrum of standing spin wave modes in a continuous ferromagnetic thin film without lithographic modification to the film. Obtaining the resonance field for a localized mode is not trivial due to the effect of the confined and inhomogeneous magnetization precession. We compare the results of micromagnetic and analytic methods to find the resonance field of localized modes in a ferromagnetic thin film, and investigate the accuracy of these methods by comparing with a numerical minimization technique that assumes Bessel function modes with pinned boundary conditions. We find that the micromagnetic technique, while computationally more intensive, reveals that the true magnetization profiles of localized modes are similar to Bessel functions with gradually decaying dynamic magnetization at the mode edges. We also find that an analytic solution, which is simple to implement and computationally much faster than other methods, accurately describes the resonance field of localized modes when exchange fields are negligible, and demonstrating the accessibility of localized mode analysis.
Localized vortices in ηi-modes
International Nuclear Information System (INIS)
Nycander, J.; Lynov, J.P.; Juul Rasmussen, J.
1992-01-01
For a wide variety of nonlinear wave equations necessary conditions for the existence of localized, stationary structures can be found by applying a simple procedure, involving two steps: First the linear dispersion relation is obtained and the regions of the phase velocity of linear waves found. Secondly, assuming that localized solutions exist, their velocities are determined by using integral relations. The obtained velocity takes the form of a ''center of mass velocity''. If this velocity falls outside the regions of phase velocities for linear waves then nonlinear localized vortices may exist. Otherwise, the structure will couple to the linear waves and gradually disperse. Applying this method we have shown that monopole vortex solutions exist for drift waves driven by the ion temperature gradient in a magnetized plasma, the so-called η i -modes. Numerical solutions show that such vortices are steadily propagating and stable and they generally emerge from localized initial conditions. Our study is motivated by recent high resolution simulations of η i -turbulence, where it was observed that coherent vortices developed spontaneously. These had a dominating influence on the evolution of the turbulence, and the associated anomalous transport was found to be significantly reduced as compared with the predictions from quasilinear theory. (author) 8 refs., 3 figs
Parallelized preconditioned BiCGStab solution of sparse linear system equations in F-COBRA-TF
International Nuclear Information System (INIS)
Geemert, Rene van; Glück, Markus; Riedmann, Michael; Gabriel, Harry
2011-01-01
Recently, the in-house development of a preconditioned and parallelized BiCGStab solver has been pursued successfully in AREVA’s advanced sub-channel code F-COBRA-TF. This solver can be run either in a sequential computation mode on a single CPU, or in a parallel computation mode on multiple parallel CPUs. The developed procedure enables the computation of several thousands of successive sparse linear system solutions in F-COBRA-TF with acceptable wall clock run times. The current paper provides general information about F-COBRA-TF in terms of modeling capabilities and application areas, and points out where the relevance arises for the efficient iterative solution of sparse linear systems. Furthermore, the preconditioning and parallelization strategies in the developed BiCGStab iterative solution approach are discussed. The paper is concluded with a number of verification examples. (author)
Impact of insulin like growth factor-1 in development of coronary artery ectasia
Directory of Open Access Journals (Sweden)
Ibrahim Faruk Akturk
2014-09-01
Full Text Available Coronary artery ectasia (CAE is characterized by inappropriate dilatation of the coronary vasculature. The mechanisms of CAE are not well known. Insulin-like growth factor-1 (IGF-1 may make endothelial cells and smooth muscle cells more sensitive to the effects of growth hormone. In the present study, we hypothesized that IGF-1 may have an impact on the formation of ectasia and aneurysm in arterial system, and aimed to investigate the associations between the presence of CAE and serum IGF-1 levels in patients undergoing coronary angiography. The study included 2.980 subjects undergoing elective diagnostic coronary angiography. We selected 40 patients diagnosed with CAE as CAE group and 44 subjects with absolutely normal coronary arteries were assigned as normal control group. IGF-1 levels were measured in both groups of patients. Groups were similar in terms of age, sex and coronary artery disease risk factors. The serum IGF-1 levels were significantly higher in CAE patients with 109.64±54.64 ng/mL than in controls with 84.76±34.01 ng/mL (p=0.016. HDL levels were lower in ectasia group with 41.5±10.7 mg/dL than controls with 47.7±10.4 mg/dL (p=0.018. By means of logistic regression analysis, high IGF-1 and low HDL levels were found to be independent risk factors for the presence of CAE (p<0.02, p<0.016, respectively. The study revealed that there was a positive correlation between serum IGF-1 levels and presence of CAE, and high IGF-1 levels and low HDL levels were independent risk factors for the presence of CAE. Future studies are needed to confirm these results.
On sliding mode observer for a hybrid three-cell converter
Khelouat, Samir
2013-10-01
In this paper, we propose a sliding mode observer to estimate the capacitor voltages of the 3-cell converter. New concept recently introduced, based on geometrical condition for observability analysis is used. The convergence of estimation error based on the solution of an LMI system is shown. Finally, illustrative results are given in order to show the efficiency of the designed observer. © 2013 IEEE.
Precise Point Positioning Using Triple GNSS Constellations in Various Modes
Directory of Open Access Journals (Sweden)
Akram Afifi
2016-05-01
Full Text Available This paper introduces a new dual-frequency precise point positioning (PPP model, which combines the observations from three different global navigation satellite system (GNSS constellations, namely GPS, Galileo, and BeiDou. Combining measurements from different GNSS systems introduces additional biases, including inter-system bias and hardware delays, which require rigorous modelling. Our model is based on the un-differenced and between-satellite single-difference (BSSD linear combinations. BSSD linear combination cancels out some receiver-related biases, including receiver clock error and non-zero initial phase bias of the receiver oscillator. Forming the BSSD linear combination requires a reference satellite, which can be selected from any of the GPS, Galileo, and BeiDou systems. In this paper three BSSD scenarios are tested; each considers a reference satellite from a different GNSS constellation. Natural Resources Canada’s GPSPace PPP software is modified to enable a combined GPS, Galileo, and BeiDou PPP solution and to handle the newly introduced biases. A total of four data sets collected at four different IGS stations are processed to verify the developed PPP model. Precise satellite orbit and clock products from the International GNSS Service Multi-GNSS Experiment (IGS-MGEX network are used to correct the GPS, Galileo, and BeiDou measurements in the post-processing PPP mode. A real-time PPP solution is also obtained, which is referred to as RT-PPP in the sequel, through the use of the IGS real-time service (RTS for satellite orbit and clock corrections. However, only GPS and Galileo observations are used for the RT-PPP solution, as the RTS-IGS satellite products are not presently available for BeiDou system. All post-processed and real-time PPP solutions are compared with the traditional un-differenced GPS-only counterparts. It is shown that combining the GPS, Galileo, and BeiDou observations in the post-processing mode improves the
A study of tearing modes via electron cyclotron emission from tokamak plasmas
International Nuclear Information System (INIS)
Ren, C.
1998-07-01
This thesis studies several tearing mode problems from both theoretical and experimental points of view. A major part of this thesis is to demonstrate that Electron Cyclotron Emission (ECE) is an excellent diagnostic for studying an MHD mode structure and its properties in a tokamak plasma. It is shown that an MHD mode can be detected from the electron temperature fluctuations measured by ECE. The amplitude and phase profiles of the fluctuations contain detailed information about the mode structure. The ECE fluctuation phase profile indicates the magnetic island deformation due to the combination of sheared flow and viscosity. A model is presented to relate qualitatively the observed phase gradient to the local magnetic field, flow velocity shear and viscosity in a 2D slab geometry, using an ideal Ohm's law and the plasma momentum equation including flow and viscosity. Numerical solution of the resultant Grad-Shafranov-like equation describing the deformed island shows that the experimentally observed value of the phase gradient can be obtained under realistic parameters for the shear in the flow velocity and viscosity. A new approach to the tearing mode stability boundary and saturation level is also presented
A study of tearing modes via electron cyclotron emission from tokamak plasmas
Energy Technology Data Exchange (ETDEWEB)
Ren, Chuang [Univ. of Wisconsin, Madison, WI (United States)
1998-07-01
This thesis studies several tearing mode problems from both theoretical and experimental points of view. A major part of this thesis is to demonstrate that Electron Cyclotron Emission (ECE) is an excellent diagnostic for studying an MHD mode structure and its properties in a tokamak plasma. It is shown that an MHD mode can be detected from the electron temperature fluctuations measured by ECE. The amplitude and phase profiles of the fluctuations contain detailed information about the mode structure. The ECE fluctuation phase profile indicates the magnetic island deformation due to the combination of sheared flow and viscosity. A model is presented to relate qualitatively the observed phase gradient to the local magnetic field, flow velocity shear and viscosity in a 2D slab geometry, using an ideal Ohm`s law and the plasma momentum equation including flow and viscosity. Numerical solution of the resultant Grad-Shafranov-like equation describing the deformed island shows that the experimentally observed value of the phase gradient can be obtained under realistic parameters for the shear in the flow velocity and viscosity. A new approach to the tearing mode stability boundary and saturation level is also presented.
Evaluation of connected vehicle impact on mobility and mode choice
Directory of Open Access Journals (Sweden)
Simon Minelli
2015-10-01
Full Text Available Connected vehicle is emerging as a solution to exacerbating congestion problems in urban areas. It is important to understand the impacts of connected vehicle on network and travel behavior of road users. The main objective of this paper is to evaluate the impact of connected vehicle on the mode choice and mobility of transportation networks. An iterative methodology was used in this paper where demands for various modes were modified based on the changes in travel time between each origin-destination (OD pair caused by introduction of connected vehicle. Then a traffic assignment was performed in a micro-simulation model, which was able to accurately simulate vehicle-to-vehicle communication. It is assumed that vehicles are equipped with a dynamic route guidance technology to choose their own route using real-time traffic information obtained through communication. The travel times obtained from the micro-simulation model were compared with a base scenario with no connected vehicle. The methodology was tested for a portion of Downtown Toronto, Ontario, Canada. In order to quantify changes in mode share with changes in travel time associated with each OD pair, mode choice models were developed for auto, transit, cycling and pedestrians using data mainly from the Transportation Tomorrow Survey. The impact of connected vehicle on mode choice was evaluated for different market penetrations of connected vehicle. The results of this study show that average travel times for the whole auto mode will generally increase, with the largest increase from connected vehicles. This causes an overall move away from the auto mode for high market penetrations if a dynamic route guidance algorithm is implemented.
Shigeta, M.; Sato, T.; Dasgupta, B.
1985-01-01
The magnetohydrodynamic stability of streaming tearing mode is investigated numerically. A bulk plasma flow parallel to the antiparallel magnetic field lines and localized in the neutral sheet excites a streaming tearing mode more strongly than the usual tearing mode, particularly for the wavelength of the order of the neutral sheet width (or smaller), which is stable for the usual tearing mode. Interestingly, examination of the eigenfunctions of the velocity perturbation and the magnetic field perturbation indicates that the streaming tearing mode carries more energy in terms of the kinetic energy rather than the magnetic energy. This suggests that the streaming tearing mode instability can be a more feasible mechanism of plasma acceleration than the usual tearing mode instability.
Competition and evolution of dielectric waveguide mode and plasmonic waveguide mode
Yuan, Sheng-Nan; Fang, Yun-Tuan
2017-10-01
In order to study the coupling and evolution law of the waveguide mode and two plasmonic surface modes, we construct a line defect waveguide based on hexagonal honeycomb plasmonic photonic crystal. Through adjusting the radius of the edge dielectric rods, the competition and evolution behaviors occur between dielectric waveguide mode and plasmonic waveguide mode. There are three status: only plasmonic waveguide modes occur for rA 0.25a; two kinds of modes coexist for 0.09a advantages in achieving slow light.
Contribution to the study of the reaction p + 11B = 3 α by the coincidence method
International Nuclear Information System (INIS)
Laugier, J.Ph.
1969-01-01
We have studied the production mode of the 3 α system in the reaction p + 11 B = 12 C * = α + 8 Be * ; 8 Be * = α + α. We have got some information for three different effects: the influence of the 8 Be residual nucleus states = sequential decay; the influence of the 12 C compound nucleus states = spin effect; an interference effect. We give a theoretical expression of the different spectra which take into account the observed phenomena. We have taken, as a parameter, the phase shift, between the waves associated with the detected particles, which produce the interference effect. The main characteristics of the experimental devices are : self supporting boron targets; cooled semiconductor detectors; multi-parametric system: for each nuclear event three parameters are recorded: the energies of the detected particles and the time of the detection; Recording system: the information are recorded on a magnetic tape and at the same time treated with an on line CAE 510 computer. The CAE 510 computer is used in delayed time to analyse the experimental data. (author) [fr
Natural Frequencies and Mode Shapes of Statically Deformed Inclined Risers
Alfosail, Feras
2016-10-15
We investigate numerically the linear vibrations of inclined risers using the Galerkin approach. The riser is modeled as an Euler-Bernoulli beam accounting for the nonlinear mid-plane stretching and self-weight. After solving for the initial deflection of the riser due to self-weight, we use a Galerkin expansion employing 15 axially loaded beam mode shapes to solve the eigenvalue problem of the riser around the static equilibrium configuration. This yields the riser natural frequencies and corresponding exact mode shapes for various values of inclination angles and tension. The obtained results are validated against a boundary-layer analytical solution and are found to be in good agreement. This constitutes a basis to study the nonlinear forced vibrations of inclined risers.
Roy, Susmita; Yashonath, Subramanian; Bagchi, Biman
2015-03-28
A self-consistent mode coupling theory (MCT) with microscopic inputs of equilibrium pair correlation functions is developed to analyze electrolyte dynamics. We apply the theory to calculate concentration dependence of (i) time dependent ion diffusion, (ii) intermediate scattering function of the constituent ions, and (iii) ion solvation dynamics in electrolyte solution. Brownian dynamics with implicit water molecules and molecular dynamics method with explicit water are used to check the theoretical predictions. The time dependence of ionic self-diffusion coefficient and the corresponding intermediate scattering function evaluated from our MCT approach show quantitative agreement with early experimental and present Brownian dynamic simulation results. With increasing concentration, the dispersion of electrolyte friction is found to occur at increasingly higher frequency, due to the faster relaxation of the ion atmosphere. The wave number dependence of intermediate scattering function, F(k, t), exhibits markedly different relaxation dynamics at different length scales. At small wave numbers, we find the emergence of a step-like relaxation, indicating the presence of both fast and slow time scales in the system. Such behavior allows an intriguing analogy with temperature dependent relaxation dynamics of supercooled liquids. We find that solvation dynamics of a tagged ion exhibits a power law decay at long times-the decay can also be fitted to a stretched exponential form. The emergence of the power law in solvation dynamics has been tested by carrying out long Brownian dynamics simulations with varying ionic concentrations. The solvation time correlation and ion-ion intermediate scattering function indeed exhibit highly interesting, non-trivial dynamical behavior at intermediate to longer times that require further experimental and theoretical studies.
Directory of Open Access Journals (Sweden)
B. Godongwana
2010-01-01
Full Text Available This paper presents an analytical model of substrate mass transfer through the lumen of a membrane bioreactor. The model is a solution of the convective-diffusion equation in two dimensions using a regular perturbation technique. The analysis accounts for radial-convective flow as well as axial diffusion of the substrate specie. The model is applicable to the different modes of operation of membrane bioreactor (MBR systems (e.g., dead-end, open-shell, or closed-shell mode, as well as the vertical or horizontal orientation. The first-order limit of the Michaelis-Menten equation for substrate consumption was used to test the developed model against available analytical results. The results obtained from the application of this model, along with a biofilm growth kinetic model, will be useful in the derivation of an efficiency expression for enzyme production in an MBR.
Arakelyan, E. K.; Andryushin, A. V.; Burtsev, S. Y.; Andryushin, K. A.
2017-11-01
The analysis of technical and parametric constraints on the adjustment range of highpower CCP and recommended technological solutions in the technical literature for their elimination. Established that in the conditions of toughening the requirements for economy, reliability and maneuverability on the part of the system operator with the participation of CCP in control the frequency and power in the power system, existing methods do not ensure the fulfillment of these requirements. The current situation in the energy sector — the lack of highly manoeuvrable power equipment leads to the need participate in control of power consumption diagrams for all types of power plants, including CCP, although initially they were intended primarily for basic loads. Large-scale research conducted at the department of Automated control systems of technological processes, showed the possibility of a significant expansion of the adjustment range of CCP when it operating in the condensing mode and in the heating mode. The report presents the main results of these research for example the CCP-450 and CCP-450T. Various technological solutions are considered: when CCP in the condensation mode — the use of bypass steam distribution schemes, the transfer of a part of the steam turbine into a low-steam mode; when CCP operation in the heating mode — bypass steam distribution and the transfer CCP to gas turbine unit — power heating plants mode with the transfer the steam turbine to the motor mode. Data on the evaluation of the technical and economic feasibility of the proposed innovative technological solutions are presented in comparison with the methods used to solve this problem, which are used in practice, such as passing through the failures of the electric load graphs by transferring the CCP to the mode of operation with incomplete equipment. When comparing, both the economics, and the maneuverability and reliability of the equipment are considered.
Simple and Accurate Analytical Solutions of the Electrostatically Actuated Curled Beam Problem
Younis, Mohammad I.
2014-01-01
We present analytical solutions of the electrostatically actuated initially deformed cantilever beam problem. We use a continuous Euler-Bernoulli beam model combined with a single-mode Galerkin approximation. We derive simple analytical expressions
Mode coupling in hybrid square-rectangular lasers for single mode operation
Energy Technology Data Exchange (ETDEWEB)
Ma, Xiu-Wen; Huang, Yong-Zhen, E-mail: yzhuang@semi.ac.cn; Yang, Yue-De; Xiao, Jin-Long; Weng, Hai-Zhong; Xiao, Zhi-Xiong [State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100083 (China)
2016-08-15
Mode coupling between a square microcavity and a Fabry-Pérot (FP) cavity is proposed and demonstrated for realizing single mode lasers. The modulations of the mode Q factor as simulation results are observed and single mode operation is obtained with a side mode suppression ratio of 46 dB and a single mode fiber coupling loss of 3.2 dB for an AlGaInAs/InP hybrid laser as a 300-μm-length and 1.5-μm-wide FP cavity connected to a vertex of a 10-μm-side square microcavity. Furthermore, tunable single mode operation is demonstrated with a continuous wavelength tuning range over 10 nm. The simple hybrid structure may shed light on practical applications of whispering-gallery mode microcavities in large-scale photonic integrated circuits and optical communication and interconnection.
Integrated core-SOL simulations of L-mode plasma in ITER and Indian demo
International Nuclear Information System (INIS)
Wisitsorasak, Apiwat; Onjun, Thawatchai; Kanjanaput, Wittawat
2015-01-01
Core-SOL simulations are carried out using 1.5D BALDUR integrated predictive modeling code to investigate tokamak plasma in ITER and Indian DEMO reactors operating in low confinement mode (L-Mode). In each simulation, the plasma current, temperature, and density profiles in both core and SOL region are evolved self-consistency. The SOL is simulated by integrating the fluid equations, including sources, along the field lines. The solutions in SOL subsequently provide as the boundary conditions of core plasma region on low-confinement mode. The core plasma transport model is described using a combination of anomalous transport by Multi-Mode-Model version 2001 (MMM2001) and neoclassical transport calculated by NCLASS module together with the toroidal velocity based on the torque due to Neoclassical Toroidal Viscosity (NTV). In addition, a sensitivity analysis is explored by varying plasma parameters, such as plasma density and auxiliary heating power. Furthermore, the ignition tests are conducted to observed plasma response in each design after shutting down an auxiliary heating. (author)
International Nuclear Information System (INIS)
Min, K.S.; Lee, B.H.
1988-01-01
Computer-aided-engineering (CAE) is an essential tool for modern nuclear power plant engineering. It greatly varies in definition, application, and technology from project to project and company to company. Despite the fast growing technologies and applications of CAE, its complexity and variety have thrown another puzzle to management of a nuclear project. Without due consideration of an integrated CAE system in early planning stage, the overall efficiency of a nuclear project would slow down due to the inefficiency in data flow. In this application are discussed under the Korea Power engineering Company philosophy in CAE approach
Ozil IP torsional mode versus combined torsional/longitudinal microcoaxial phacoemulsification.
Helvacioglu, Firat; Tunc, Zeki; Yeter, Celal; Oguzhan, Hasan; Sencan, Sadik
2012-01-01
To compare the safety and efficacy of microcoaxial phacoemulsification surgeries performed with the Ozil Intelligent Phaco (IP) torsional mode and combined torsional/longitudinal ultrasound (US) mode using the Infiniti Vision System (Alcon Laboratories). In this prospective randomized comparative study, 60 eyes were assigned to 2.2-mm microcoaxial phacoemulsification using the Ozil IP torsional mode (group 1) or combined torsional/longitudinal US mode (group 2). The primary outcome measures were US time (UST), cumulative dissipated energy (CDE), longitudinal and torsional ultrasound amplitudes, mean operation time, mean volume of balanced salt solution (BSS) used, and surgical complications. Both groups included 30 eyes. Mean UST, CDE, and longitudinal and torsional ultrasound amplitudes in group 1 were 1 minute 15±34.33 seconds, 8.74±5.64, 0.43±0.74, and 25.56±8.56, respectively, and these parameters in group 2 were 1 minute 40±51.44 seconds, 9.28±5.99, 3.64±1.55, and 3.71±1.34, respectively. UST and longitudinal amplitudes were found to be significantly low in group 1 (p<0.001, p<0.001), whereas torsional amplitude was found to be significantly high in this group (p=0.001). Mean volumes of BSS used in groups 1 and 2 were 63.30±18.00 cc and 84.50±28.65 cc, respectively (p=0.001). The Ozil IP torsional mode may provide more effective lens removal than the combined torsional/longitudinal US mode with a lower UST and volume of BSS used.
DEFF Research Database (Denmark)
Jensen, P.S.; Bak, J.
2002-01-01
of these two modes of operation. The concentrations of aqueous solutions of urea and glucose in the ranges 0-40 mg/dL and 0-250 mg/dL, respectively, were determined by principal component regression using both modes. The dual-beam technique eliminated instrumental variations present in the single...
Nonlinear stationary solutions of the Wigner and Wigner-Poisson equations
Haas, F.; Shukla, P. K.
2008-01-01
Exact nonlinear stationary solutions of the one-dimensional Wigner and Wigner-Poisson equations in the terms of the Wigner functions that depend not only on the energy but also on position are presented. In this way, the Bernstein-Greene-Kruskal modes of the classical plasma are adapted for the quantum formalism in the phase space. The solutions are constructed for the case of a quartic oscillator potential, as well as for the self-consistent Wigner-Poisson case. Conditions for well-behaved p...
Energy Technology Data Exchange (ETDEWEB)
Martinand, D
2003-01-15
This analytical study deals with the spatio-temporal evolution of linear thermo-convective instabilities in a horizontal fluid layer heated from below (the Rayleigh--Benard system) and subject to a horizontal pressure gradient (Poiseuille flow). The novelty consists of a spatially inhomogeneous temperature, in the form of a two-dimensional bump imposed on the lower plate, while the upper plate is kept at a constant temperature. The inhomogeneous boundary temperature and the mean flow of the Rayleigh--Benard--Poiseuille system break the symmetries of the classical Rayleigh--Benard system. The instabilities of interest are therefore spatially localised packets of convection rolls. If a mode of this type is synchronized, it is called a global mode. Assuming that the characteristic scale of the spatial variation of the lower plate temperature is large compared to the wavelength of the rolls, global modes are sought in the form of Eigenmodes in the confined vertical direction, modulated by a two-dimensional WKBJ expansion in the slowly-varying horizontal directions. Such an expansion breaks down at points where the group velocity of the instability vanishes, i.e. at WKBJ turning points. In the neighbourhood of one such point, located at the top of the temperature bump, the boundedness of the solution imposes a selection criterion for the global modes which provides the growth rate (or equivalently the critical threshold), the frequency and the wave vector of the most amplified global mode. This study thus generalizes to two-dimensional cases the methods used and the results obtained for one-dimensional inhomogeneities. The analysis is first applied to a simplified governing equation obtained by an envelope formalism and the analytical results are compared with numerical solutions of the amplitude equation. The formalism is finally applied to the Rayleigh--Benard--Poiseuille system described by the Navier--Stokes equations with the Boussinesq approximation. (author)
Bing, Xue; Yicai, Ji
2018-06-01
In order to understand directly and analyze accurately the detected magnetotelluric (MT) data on anisotropic infinite faults, two-dimensional partial differential equations of MT fields are used to establish a model of anisotropic infinite faults using the Fourier transform method. A multi-fault model is developed to expand the one-fault model. The transverse electric mode and transverse magnetic mode analytic solutions are derived using two-infinite-fault models. The infinite integral terms of the quasi-analytic solutions are discussed. The dual-fault model is computed using the finite element method to verify the correctness of the solutions. The MT responses of isotropic and anisotropic media are calculated to analyze the response functions by different anisotropic conductivity structures. The thickness and conductivity of the media, influencing MT responses, are discussed. The analytic principles are also given. The analysis results are significant to how MT responses are perceived and to the data interpretation of the complex anisotropic infinite faults.
Analysis of a 'barb test' for measuring the mixed-mode delamination toughness of coatings
International Nuclear Information System (INIS)
Liu Yufu; Kagawa, Y.; Evans, A.G.
2008-01-01
The durability of thermal barrier coatings (TBCs) employed in most turbine engines is limited by delamination, both within the coating and at the coating-substrate interface. A test used for evaluating the mixed-mode toughness pertinent to such delaminations has been fully-analyzed by determining the steady-state energy release rate, the mode mixity and the critical length for buckling. An analytic solution based on beam theory establishes basic estimates and scaling relationships. Selected finite-element calculations have been used to affirm the fidelity of the results. The energy release rate attains steady-state, but the phase angle changes throughout because of a small (but significant) bending moment induced at the supports. The coating buckles at a critical delamination length, whereupon the energy release rate increases rapidly and violates steady state. The solutions are used to re-interpret measurements reported in the literature for an electron beam physically deposited TBC
Research of application mode for FTTX technology
Wang, Zhong; Yun, Xiang; Huang, Wei
2009-08-01
With rapid development of Internet and broadband access network, the technologies of xDSL, FTTx+LAN, WLAN have more applications, new network service emerges in endless stream, especially the increase of network game, meeting TV, video on demand, etc. FTTH supports all present and future service with enormous bandwidth, including traditional telecommunication service, traditional data service and traditional TV service, and the future digital TV and VOD. With huge bandwidth of FTTH, it wins the final solution of broadband network, becomes the final goal of development of optical access network. In this paper, technique theory of EPON is introduced at first. At the same time, MAC frame structure, automatic detection and ranging of MPCP, DBA,and multi-LLID of EPON is analyzed. Then, service development ability, cost advantage and maintenance superiority based on EPON technology are carried out. At last,with Cost comparison between FTTH / FTTB building model and the traditional model, FTTB + LAN mode which is suitable for the newadding residential users in general areas and FTTN + DSL mode which is suitable for the old city and rural access network transformation are built up in detail. And FTTN + DSL project of rural information in rural areas and FTTH broadband HOUSE project on service solutions program are analyzed. comparing to the traditional access technologies, EPON technology has the obvious advantages, such as distance transmission, high or wide band, saving line resources, service abilities, etc. These are the qualities which not only be served for home users, but solve more access problems for us effectively.
Theoretical study on the sound absorption of electrolytic solutions. I. Theoretical formulation
Yamaguchi, T.; Matsuoka, T.; Koda, S.
2007-04-01
A theory is formulated that describes the sound absorption of electrolytic solutions due to the relative motion of ions, including the formation of ion pairs. The theory is based on the Kubo-Green formula for the bulk viscosity. The time correlation function of the pressure is projected onto the bilinear product of the density modes of ions. The time development of the product of density modes is described by the diffusive limit of the generalized Langevin equation, and approximate expressions for the three- and four-body correlation functions required are given with the hypernetted-chain integral equation theory. Calculations on the aqueous solutions of model electrolytes are performed. It is demonstrated that the theory describes both the activated barrier crossing between contact and solvent-separated ion pairs and the Coulombic correlation between ions.
Kao, Shih-Chun; Westfall, Daniel R; Soneson, Jack; Gurd, Brendon; Hillman, Charles H
2017-09-01
The purpose of this study was to investigate the effects of a single bout of high-intensity interval training (HIIT) and continuous aerobic exercise (CAE) on inhibitory control. The P3 component of the stimulus-locked ERP was collected in 64 young adults during a modified flanker task following 20 min of seated rest, 20 min of CAE, and 9 min of HIIT on separate days in counterbalanced order. Participants exhibited shorter overall reaction time following CAE and HIIT compared to seated rest. Response accuracy improved following HIIT in the task condition requiring greater inhibitory control compared to seated rest and CAE. P3 amplitude was larger following CAE compared to seated rest and HIIT. Decreased P3 amplitude and latency were observed following HIIT compared to seated rest. The current results replicated previous findings indicating the beneficial effect of acute CAE on behavioral and neuroelectric indices of inhibitory control. With a smaller duration and volume of exercise, a single bout of HIIT resulted in additional improvements in inhibitory control, paralleled by a smaller and more efficient P3 component. In sum, the current study demonstrated that CAE and HIIT differentially facilitate inhibitory control and its underlying neuroelectric activation, and that HIIT may be a time-efficient approach for enhancing cognitive health. © 2017 Society for Psychophysiological Research.
Ge, Qingchun; Han, Gang; Chung, Tai-Shung
2016-03-01
Effective removal of As(III) from water by an oxalic acid complex with the formula of Na3[Cr(C2O4)3] (Na-Cr-OA) is demonstrated via an forward osmosis-membrane distillation (FO-MD) hybrid system in this study. Na-Cr-OA first proved its superiority as a draw solute with high water fluxes and negligible reverse fluxes in FO, then a systematic investigation of the Na-Cr-OA promoted FO process was conducted to ascertain the factors in As(III) removal. Relatively high water fluxes of 28 LMH under the FO mode and 74 LMH under the pressure retarded osmosis (PRO) mode were achieved when using a 1000 ppm As(III) solution as the feed and 1.0 M Na-Cr-OA as the draw solution at 60 °C. As(III) removal with a water recovery up to 21.6% (FO mode) and 48.3% (PRO mode) were also achieved in 2 h. An outstanding As(III) rejection with 30-3000 μg/L As(III) in the permeate was accomplished when As(III) feed solutions varied from 5 × 10(4) to 1 × 10(6) μg/L, superior to the best FO performance reported for As(III) removal. Incorporating MD into FO not only makes As(III) removal sustainable by reconcentrating the Na-Cr-OA solution simultaneously, but also reduces the As(III) concentration below 10 μg/L in the product water, meeting the WHO standard.
Analytical Lie-algebraic solution of a 3D sound propagation problem in the ocean
Energy Technology Data Exchange (ETDEWEB)
Petrov, P.S., E-mail: petrov@poi.dvo.ru [Il' ichev Pacific Oceanological Institute, 43 Baltiyskaya str., Vladivostok, 690041 (Russian Federation); Prants, S.V., E-mail: prants@poi.dvo.ru [Il' ichev Pacific Oceanological Institute, 43 Baltiyskaya str., Vladivostok, 690041 (Russian Federation); Petrova, T.N., E-mail: petrova.tn@dvfu.ru [Far Eastern Federal University, 8 Sukhanova str., 690950, Vladivostok (Russian Federation)
2017-06-21
The problem of sound propagation in a shallow sea with variable bottom slope is considered. The sound pressure field produced by a time-harmonic point source in such inhomogeneous 3D waveguide is expressed in the form of a modal expansion. The expansion coefficients are computed using the adiabatic mode parabolic equation theory. The mode parabolic equations are solved explicitly, and the analytical expressions for the modal coefficients are obtained using a Lie-algebraic technique. - Highlights: • A group-theoretical approach is applied to a problem of sound propagation in a shallow sea with variable bottom slope. • An analytical solution of this problem is obtained in the form of modal expansion with analytical expressions of the coefficients. • Our result is the only analytical solution of the 3D sound propagation problem with no translational invariance. • This solution can be used for the validation of the numerical propagation models.
International Nuclear Information System (INIS)
Comodi, Gabriele; Carducci, Francesco; Sze, Jia Yin; Balamurugan, Nagarajan; Romagnoli, Alessandro
2017-01-01
This paper addresses the role of energy storage in cooling applications. Cold energy storage technologies addressed are: Li-Ion batteries (Li-Ion EES), sensible heat thermal energy storage (SHTES); phase change material (PCM TES), compressed air energy storage (CAES) and liquid air energy storage (LAES). Batteries and CAES are electrical storage systems which run the cooling systems; SHTES and PCM TES are thermal storage systems which directly store cold energy; LAES is assessed as a hybrid storage system which provides both electricity (for cooling) and cold energy. A hybrid quantitative-qualitative comparison is presented. Quantitative comparison was investigated for different sizes of daily cooling energy demand and three different tariff scenarios. A techno-economic analysis was performed to show the suitability of the different storage systems at different scales. Three parameters were used (Pay-back period, Savings-per-energy-unit and levelized-cost-of-energy) to analyze and compare the different scenarios. The qualitative analysis was based on five comparison criteria (Complexity, Technology Readiness Level, Sustainability, Flexibility and Safety). Results showed the importance of weighing the pros and cons of each technology to select a suitable cold energy storage system. Techno-economic analysis highlighted the fundamental role of tariff scenario: a greater difference between peak and off-peak electricity tariff leads to a shorter payback period of each technology. - Highlights: • Techno-economic evaluation of energy storage solutions for cooling applications. • Comparison between five energy storage (EES, SHTES, PCM, CAES, LAES) is performed. • Qualitative and quantitative performance parameters were used for the analysis. • LAES/PCM can be valid alternatives to more established technologies EES, SHTES, CAES. • Tariffs, price arbitrage and investment cost play a key role in energy storage spread.
Lee, M S; Seo, S R; Kim, J-C
2012-10-01
Pressure sores are lesions caused by impaired blood flow. Conventional dressings can absorb exudates, but do not promote wound healing. A hydrogel composed of β-cyclodextrin (β-CD), polyethyleneimine (PEI) and silk fibroin (SF) was assessed for use in healing of pressure sores. The hydrogel was prepared by crosslinking β-CD-grafted PEI and SF using epichlorohydrin. The gel was then immersed in an aqueous solution of Centella asiatica extract (CAE) 0.7 mg/mL and/or hydrocortisone acetate (HCA) 0.5 mg/mL. The in vivo pressure sore-healing efficacy of the dry gel (with or without the drugs) was investigated in terms of the hyperplasia of epidermis and the number of neutrophils in the skin tissue. The specific loading of CAE was 0.0091 g/g of dry gel. The percentage of CAE released at 24 h at pH 3.0, 5.0 and 7.4 was approximately 63.9%, 55.0% and 44.4%, respectively. This pH-dependent release is possibly due to the degree of gel swelling, which decreased with increasing pH. The specific loading of HCA was 0.0050 g/g dry gel, and the percentage release of HCA at 24 h was around 20% at all three pH points. It is likely that HCA release is independent of pH. HCA is a hydrophobic compound, and therefore the release of HCA is affected by the partitioning of HCA between the β-CD cavity and the bulk water phase, but not by the degree of swelling of the hydrogel. The pressure sores treated with the hydrogel healed in 6 days, compared with 10 days for controls. In this study, a β-CD/PEI/SF hydrogel containing CAE and HCA reduced the healing time for pressure sores. © The Author(s). CED © 2012 British Association of Dermatologists.
Masood, W.; Mirza, Arshad M.
2010-11-01
Linear and nonlinear properties of coupled Shukla-Varma (SV) and convective cell modes in the presence of electron thermal effects are studied in a nonuniform magnetoplasma composed of electrons, ions, and extremely massive and negatively charged immobile dust grains. In the linear case, the modified dispersion relation is given and, in the nonlinear case, stationary solutions of the nonlinear equations that govern the dynamics of coupled SV and convective cell modes are obtained. It is found that electrostatic dipolar and vortex street type solutions can appear in such a plasma. The relevance of the present investigation with regard to the Earth's mesosphere as well as in ionospheric plasmas is also pointed out.
International Nuclear Information System (INIS)
Masood, W.; Mirza, Arshad M.
2010-01-01
Linear and nonlinear properties of coupled Shukla-Varma (SV) and convective cell modes in the presence of electron thermal effects are studied in a nonuniform magnetoplasma composed of electrons, ions, and extremely massive and negatively charged immobile dust grains. In the linear case, the modified dispersion relation is given and, in the nonlinear case, stationary solutions of the nonlinear equations that govern the dynamics of coupled SV and convective cell modes are obtained. It is found that electrostatic dipolar and vortex street type solutions can appear in such a plasma. The relevance of the present investigation with regard to the Earth's mesosphere as well as in ionospheric plasmas is also pointed out.
Directory of Open Access Journals (Sweden)
Swaminathan Ganesan
2017-09-01
Full Text Available In this paper, a robust energy management solution which will facilitate the optimum and economic control of energy flows throughout a microgrid network is proposed. The increased penetration of renewable energy sources is highly intermittent in nature; the proposed solution demonstrates highly efficient energy management. This study enables precise management of power flows by forecasting of renewable energy generation, estimating the availability of energy at storage batteries, and invoking the appropriate mode of operation, based on the load demand to achieve efficient and economic operation. The predefined mode of operation is derived out of an expert rule set and schedules the load and distributed energy sources along with utility grid.
International Nuclear Information System (INIS)
Hinkel-Lipsker, D.E.; Fried, B.D.; Morales, G.J.
1993-01-01
This study provides an analytic solution to the general problem of mode conversion in an unmagnetized plasma. Specifically, an electromagnetic wave of frequency ω propagating through a plasma with a parabolic density profile of scale length L p is examined. The mode conversion points are located a distance Δ 0 from the peak of the profile, where the electron plasma frequency ω p (z) matches the wave frequency ω. The corresponding reflection, transmission, and mode conversion coefficients are expressed analytically in terms of parabolic cylinder functions for all values of Δ 0 . The method of solution is based on a source approximation technique that is valid when the electromagnetic and electrostatic scale lengths are well separated. For large Δ 0 , i.e., (cL p /ω) 1/2 much-lt Δ 0 p , the appropriately scaled result [D. E. Hinkel-Lipsker et al., Phys. Fluids B 4, 559 (1992)] for a linear density profile is recovered as the parabolic cylinder functions asymptotically become Airy functions. When Δ 0 →0, the special case of conversion at the peak of the profile [D. E. Hinkel-Lipsker et al., Phys. Fluids B 4, 1772 (1992)] is obtained
Nonlinear tearing mode and vortex chains
International Nuclear Information System (INIS)
Jovanovic, D.; Vranjes, J.
1996-01-01
We study the nonlinear stage of a tearing mode, whose island width exceeds the tearing layer thickness, and the wavelength is of the order of collisionless skin depth. A coherent solution is found in the form of a moving vortex chain. It is the result of a self-organization process, which adjusts the profile of the sheared poloidal magnetic field and excites a localized perpendicular sheared plasma flow, consisting of three counterstreaming jets. A numerical solution shows a twin chain of plasma vortices, coupled with a single chain of magnetic islands, whose width is of the order of collisionless skin depth. Adiabatic evolution of the vortex chain in the presence of small viscosity reveals its finite lifetime. The chain destruction may occur either directly, or through a sequence of bifurcations (corresponding to abrupt changes of the vortex chain parameters) to magnetic field stochastization within a layer of the collisionless skin depth scale, which occurs before the magnetic island overlapping takes place. This provides a new mechanism for the anomalous transport. (orig.)
Coupled fracture modes under anti-plane loading
Directory of Open Access Journals (Sweden)
Les P. Pook
2016-07-01
Full Text Available The linear elastic analysis of homogeneous, isotropic cracked bodies is a Twentieth Century development. It was recognised that the crack tip stress field is a singularity, but it was not until the introduction of the essentially two dimensional stress intensity factor concept in 1957 that widespread application to practical engineering problems became possible. The existence of three dimensional corner point effects in the vicinity of a corner point where a crack front intersects a free surface was investigated in the late 1970s: it was found that modes II and III cannot exist in isolation. The existence of one of these modes always induces the other. An approximate solution for corner point singularities by Bažant and Estenssoro explained some features of corner point effects but there were various paradoxes and inconsistencies. In an attempt to explain these a study was carried out on the coupled in-plane fracture mode induced by a nominal anti-plane (mode III loading applied to plates and discs weakened by a straight crack. The results derived from a large bulk of finite element models showed clearly that Bažant and Estenssoro’s analysis is incomplete. Some of the results of the study are summarised, together with some recent results for a disc under in-plane shear loading. On the basis of these results, and a mathematical argument, the results suggest that the stress field in the vicinity of a corner point is the sum of two singularities: one due to stress intensity factors and the other due to an as yet undetermined corner point singularity.
Modeling bidirectionally coupled single-mode semiconductor lasers
International Nuclear Information System (INIS)
Mulet, Josep; Masoller, Cristina; Mirasso, Claudio R.
2002-01-01
We develop a dynamical model suitable for the description of two mutually coupled semiconductor lasers in a face-to-face configuration. Our study considers the propagation of the electric field along the compound system as well as the evolution of the carrier densities within each semiconductor laser. Mutual injection, passive optical feedback, and multiple reflections are accounted for in this framework, although under weak to moderate coupling conditions. We systematically describe the effect of the coupling strength on the spectrum of monochromatic solutions and on the respective dynamical behavior. By assuming single-longitudinal-mode operation, weak mutual coupling and slowly varying approximation, the dynamical model can be reduced to rate equations describing the mutual injection from one laser to its counterpart and vice versa. A good agreement between the complete and simplified models is found for small coupling. For larger coupling, higher-order terms lead to a smaller threshold reduction, reflected itself in the spectrum of the monochromatic solutions and in the dynamics of the optical power
Adaptive variational mode decomposition method for signal processing based on mode characteristic
Lian, Jijian; Liu, Zhuo; Wang, Haijun; Dong, Xiaofeng
2018-07-01
Variational mode decomposition is a completely non-recursive decomposition model, where all the modes are extracted concurrently. However, the model requires a preset mode number, which limits the adaptability of the method since a large deviation in the number of mode set will cause the discard or mixing of the mode. Hence, a method called Adaptive Variational Mode Decomposition (AVMD) was proposed to automatically determine the mode number based on the characteristic of intrinsic mode function. The method was used to analyze the simulation signals and the measured signals in the hydropower plant. Comparisons have also been conducted to evaluate the performance by using VMD, EMD and EWT. It is indicated that the proposed method has strong adaptability and is robust to noise. It can determine the mode number appropriately without modulation even when the signal frequencies are relatively close.
TCRP H-37 Characteristics of Premium Transit Services That Affect Mode Choice: Summary of Phase 1
2010-11-15
This research seeks to improve the understanding of the full range of determinants for mode choice behavior and to offer practical solutions to practitioners on representing and distinguishing these characteristics in travel demand forecasting models...
International Nuclear Information System (INIS)
Jin-Hui, Yuan; Chong-Xiu, Yu; Xin-Zhu, Sang; Wen-Jing, Li; Gui-Yao, Zhou; Shu-Guang, Li; Lan-Tian, Hou
2009-01-01
Guided-mode characteristics of hollow-core photonic crystal fibre (HC-PCF) are experimentally and theoretically investigated. The transmission spectrum in the range from 755 to 845 nm is observed and the loss is measured to be 0.12 dB/m at 800 nm by cut-back method. Based on the full-vector beam propagation method and the full-vector plane-wave method, the characteristics of mode field over propagation distance 1 m are simulated, and the results show that the propagation efficiency can be above 80%. Compared with the fundamental guided mode well confined in air core within shorter propagation distance, the second-order guided mode leaks into the cladding region and gradually attenuates due to larger refractive index difference. The primary loss factors in HC-PCF and the corresponding solutions are elementarily discussed. (fundamental areas of phenomenology (including applications))
Guaranteed performance in reaching mode of sliding mode ...
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22
addresses the design of constant plus proportional rate reaching law-based SMC for second-order ... Reaching mode; sliding mode controlled systems; output tracking ... The uncertainty in the input distribution function g is expressed as.
Nonlinear equation of the modes in circular slab waveguides and its application.
Zhu, Jianxin; Zheng, Jia
2013-11-20
In this paper, circularly curved inhomogeneous waveguides are transformed into straight inhomogeneous waveguides first by a conformal mapping. Then, the differential transfer matrix method is introduced and adopted to deduce the exact dispersion relation for modes. This relation itself is complex and difficult to solve, but it can be approximated by a simpler nonlinear equation in practical applications, which is close to the exact relation and quite easy to analyze. Afterward, optimized asymptotic solutions are obtained and act as initial guesses for the following Newton's iteration. Finally, very accurate solutions are achieved in the numerical experiment.
Thermodynamic characteristics of a novel supercritical compressed air energy storage system
International Nuclear Information System (INIS)
Guo, Huan; Xu, Yujie; Chen, Haisheng; Zhou, Xuezhi
2016-01-01
Highlights: • A novel supercritical compressed air energy storage system is proposed. • The energy density of SC-CAES is approximately 18 times larger than that of conventional CAES. • The characteristic of thermodynamics and exergy destruction is comprehensively analysed. • The corresponding optimum relationship between charging and discharging pressure is illustrated. • A turning point of efficiency is indicated because of the heat transfer of crossing the critical point. - Abstract: A novel supercritical compressed air energy storage (SC-CAES) system is proposed by our team to solve the problems of conventional CAES. The system eliminates the dependence on fossil fuel and large gas-storage cavern, as well as possesses the advantages of high efficiency by employing the special properties of supercritical air, which is significant for the development of electrical energy storage. The thermodynamic model of the SC-CAES system is built, and the thermodynamic characters are revealed. Through the exergy analysis of the system, the processes of the larger exergy destruction include compression, expansion, cold storage/heat exchange and throttle. Furthermore, sensitivity analysis shows that there is an optimal energy releasing pressure to make the system achieve the highest efficiency when energy storage pressure is constant. The efficiency of SC-CAES is expected to reach about 67.41% when energy storage pressure and energy releasing pressure are 120 bar and 95.01 bar, respectively. At the same time, the energy density is 18 times larger than that of conventional CAES. Sensitivity analysis also shows the change laws of system efficiency varying with other basic system parameters. The study provides support for the design and engineering of SC-CAES.
Auxenfans, Celine; Menet, Veronique; Catherine, Zulma; Shipkov, Hristo; Lacroix, Pierre; Bertin-Maghit, Marc; Damour, Odile; Braye, Fabienne
2015-02-01
The aim was to review the use and indications of cultured autologous epidermis (CAE) in extensive burns and to evaluate the efficiency of our strategy of burn treatment. This retrospective study comprised 15 years (1997-2012). all patients who received CAE. patients who died before complete healing and patients who received exclusively cultured allogeneic keratinocytes. Evaluation criteria were clinical. Time and success of wound healing after CAE graft were evaluated. A total of 63 patients were included with severity Baux score of 107 (from 70 to 140) and mean percentage of TBSA of 71% (from 40% to 97%). The CAE were used as Cuono method, in STSG donor sites and deep 2nd degree burns and in combination with large-meshed STSG (1:6-1:12) in extensively burned patients. Cuono method was used in 6 patients. The final take was 16% (0-30) because of the great fragility of the obtained epidermis. Nine patients with deep 2nd degree burns (mean TBSA 81%, from 60 to 97%) were successfully treated with only CAE without skin grafting. Combined technique (STSG meshed at 1:6-1:12 covered with CAE) was used in 27 patients (mean TBSA 69%, from 49% to 96%) with 85% success rate. Finally, donor sites treated with CAE in 49 patients could be harvested several times thanks to rapid epithelialization (time of wound healing was 7 days (from 5 to 10 days)). The CAE allow rapid healing of STSG donor sites and deep 2nd second degree burns in extensively burned patients. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.
High-mode-number ballooning modes in a heliotron/torsatron system. II. Stability
International Nuclear Information System (INIS)
Nakajima, N.
1996-01-01
In heliotron/torsatron systems that have a large Shafranov shift, the local magnetic shear is found to have no stabilizing effect on high-mode-number ballooning modes at the outer side of the torus, even in the region where the global shear is stellarator-like in nature. The disappearance of this stabilization, in combination with the compression of the flux surfaces at the outer side of the torus, leads at relatively low values of the plasma pressure to significant modifications of the stabilizing effect due to magnetic field-line bending on high-mode-number ballooning modes-specifically, that the field-line bending stabilization can be remarkably suppressed or enhanced. In an equilibrium that is slightly Mercier-unstable or completely Mercier-stable due to peaked pressure profiles, such as those used in standard stability calculations, high-mode-number ballooning modes are destabilized due to these modified stability effects, with their eigenfunctions highly localized along the field line. Highly localized mode structures such as these cause the ballooning mode eigenvalues ω 2 to have a strong field line dependence (i.e., α-variation) through the strong dependence of the local magnetic curvature, such that the level surfaces of ω 2 (ψ,θ k ,α) (≤0) become spheroids in (ψ,θ k ,α) space, where ψ labels flux surfaces and θ k is the radial wave number. Because the spheroidal level surfaces for unstable eigenvalues are surrounded by level surfaces for stable eigenvalues of high-mode-number toroidal Alfvacute en eigenmodes, those high-mode-number ballooning modes never lead to low-mode-number modes. In configuration space, these high-mode-number modes are localized in a single toroidal pitch of the helical coils, and hence they may experience substantial stabilization due to finite Larmor radius effects. copyright 1996 American Institute of Physics
Packaged integrated opto-fluidic solution for harmful fluid analysis
Allenet, T.; Bucci, D.; Geoffray, F.; Canto, F.; Couston, L.; Jardinier, E.; Broquin, J.-E.
2016-02-01
Advances in nuclear fuel reprocessing have led to a surging need for novel chemical analysis tools. In this paper, we present a packaged lab-on-chip approach with co-integration of optical and micro-fluidic functions on a glass substrate as a solution. A chip was built and packaged to obtain light/fluid interaction in order for the entire device to make spectral measurements using the photo spectroscopy absorption principle. The interaction between the analyte solution and light takes place at the boundary between a waveguide and a fluid micro-channel thanks to the evanescent part of the waveguide's guided mode that propagates into the fluid. The waveguide was obtained via ion exchange on a glass wafer. The input and the output of the waveguides were pigtailed with standard single mode optical fibers. The micro-scale fluid channel was elaborated with a lithography procedure and hydrofluoric acid wet etching resulting in a 150+/-8 μm deep channel. The channel was designed with fluidic accesses, in order for the chip to be compatible with commercial fluidic interfaces/chip mounts. This allows for analyte fluid in external capillaries to be pumped into the device through micro-pipes, hence resulting in a fully packaged chip. In order to produce this co-integrated structure, two substrates were bonded. A study of direct glass wafer-to-wafer molecular bonding was carried-out to improve detector sturdiness and durability and put forward a bonding protocol with a bonding surface energy of γ>2.0 J.m-2. Detector viability was shown by obtaining optical mode measurements and detecting traces of 1.2 M neodymium (Nd) solute in 12+/-1 μL of 0.01 M and pH 2 nitric acid (HNO3) solvent by obtaining an absorption peak specific to neodymium at 795 nm.
Time-dependent local-to-normal mode transition in triatomic molecules
Cruz, Hans; Bermúdez-Montaña, Marisol; Lemus, Renato
2018-01-01
Time-evolution of the vibrational states of two interacting harmonic oscillators in the local mode scheme is presented. A local-to-normal mode transition (LNT) is identified and studied from temporal perspective through time-dependent frequencies of the oscillators. The LNT is established as a polyad-breaking phenomenon from the local standpoint for the stretching degrees of freedom in a triatomic molecule. This study is carried out in the algebraic representation of bosonic operators. The dynamics of the states are determined via the solutions of the corresponding nonlinear Ermakov equation and a local time-dependent polyad is obtained as a tool to identify the LNT. Applications of this formalism to H2O, CO2, O3 and NO2 molecules in the adiabatic, sudden and linear regime are considered.
Edge-localized mode avoidance and pedestal structure in I-mode plasmas
Energy Technology Data Exchange (ETDEWEB)
Walk, J. R., E-mail: jrwalk@psfc.mit.edu; Hughes, J. W.; Hubbard, A. E.; Terry, J. L.; Whyte, D. G.; White, A. E.; Baek, S. G.; Reinke, M. L.; Theiler, C.; Churchill, R. M.; Rice, J. E. [MIT Plasma Science and Fusion Center, Cambridge, MA 02139-4307 (United States); Snyder, P. B.; Osborne, T. [General Atomics, San Diego, CA 92186-5608 (United States); Dominguez, A [Princeton Plasma Physics Laboratory, Princeton, NJ 08543-0451 (United States); Cziegler, I. [UCSD Center for Momentum Transport and Flow Organization, La Jolla, CA 92093-0417 (United States)
2014-05-15
I-mode is a high-performance tokamak regime characterized by the formation of a temperature pedestal and enhanced energy confinement, without an accompanying density pedestal or drop in particle and impurity transport. I-mode operation appears to have naturally occurring suppression of large Edge-Localized Modes (ELMs) in addition to its highly favorable scalings of pedestal structure and overall performance. Extensive study of the ELMy H-mode has led to the development of the EPED model, which utilizes calculations of coupled peeling-ballooning MHD modes and kinetic-ballooning mode (KBM) stability limits to predict the pedestal structure preceding an ELM crash. We apply similar tools to the structure and ELM stability of I-mode pedestals. Analysis of I-mode discharges prepared with high-resolution pedestal data from the most recent C-Mod campaign reveals favorable pedestal scalings for extrapolation to large machines—pedestal temperature scales strongly with power per particle P{sub net}/n{sup ¯}{sub e}, and likewise pedestal pressure scales as the net heating power (consistent with weak degradation of confinement with heating power). Matched discharges in current, field, and shaping demonstrate the decoupling of energy and particle transport in I-mode, increasing fueling to span nearly a factor of two in density while maintaining matched temperature pedestals with consistent levels of P{sub net}/n{sup ¯}{sub e}. This is consistent with targets for increased performance in I-mode, elevating pedestal β{sub p} and global performance with matched increases in density and heating power. MHD calculations using the ELITE code indicate that I-mode pedestals are strongly stable to edge peeling-ballooning instabilities. Likewise, numerical modeling of the KBM turbulence onset, as well as scalings of the pedestal width with poloidal beta, indicates that I-mode pedestals are not limited by KBM turbulence—both features identified with the trigger for large ELMs
Growth Kinematics of Opening-Mode Fractures
Eichhubl, P.; Alzayer, Y.; Laubach, S.; Fall, A.
2014-12-01
Fracture aperture is a primary control on flow in fractured reservoirs of low matrix permeability including unconventional oil and gas reservoirs and most geothermal systems. Guided by principles of linear elastic fracture mechanics, fracture aperture is generally assumed to be a linear function of fracture length and elastic material properties. Natural opening-mode fractures with significant preserved aperture are observed in core and outcrop indicative of fracture opening strain accommodated by permanent solution-precipitation creep. Fracture opening may thus be decoupled from length growth if the material effectively weakens after initial elastic fracture growth by either non-elastic deformation processes or changes in elastic properties. To investigate the kinematics of fracture length and aperture growth, we reconstructed the opening history of three opening-mode fractures that are bridged by crack-seal quartz cement in Travis Peak Sandstone of the SFOT-1 well, East Texas. Similar crack-seal cement bridges had been interpreted to form by repeated incremental fracture opening and subsequent precipitation of quartz cement. We imaged crack-seal cement textures for bridges sampled at varying distance from the tips using scanning electron microscope cathodoluminescence, and determined the number and thickness of crack-seal cement increments as a function of position along the fracture length and height. Observed trends in increment number and thickness are consistent with an initial stage of fast fracture propagation relative to aperture growth, followed by a stage of slow propagation and pronounced aperture growth. Consistent with fluid inclusion observations indicative of fracture opening and propagation occurring over 30-40 m.y., we interpret the second phase of pronounced aperture growth to result from fracture opening strain accommodated by solution-precipitation creep and concurrent slow, possibly subcritical, fracture propagation. Similar deformation
Computer-Aided Manufacturing of 3D Workpieces
Cornelia Victoria Anghel Drugarin; Mihaela Dorica Stroia
2017-01-01
Computer-Aided Manufacturing (CAM) assumes to use dedicated software for controlling machine tools and similar devices in the process of workpieces manufacturing. CAM is, in fact, an application technology that uses computer software and machinery to simplify and automate manufacturing processes. CAM is the inheritor of computer-aided engineering (CAE) and is often used conjunctively with computer-aided design (CAD). Advanced CAM solutions are forthcoming and have a large ...
Thermodynamical aspect of black hole solutions in heteric string theory
Fujisaki, H
2003-01-01
Thermodynamical properties of charged rotating dilatonic black holes are discussed on the basis of the general solution of Sen in the heterotic string theory compactified on a six dimensional torus. The most probable microcanonical configuration of black holes is then described in the single-massive-mode dominance scenario.
Low-bending loss and single-mode operation in few-mode optical fiber
Yin, Ping; Wang, Hua; Chen, Ming-Yang; Wei, Jin; Cai, Zhi-Min; Li, Lu-Ming; Yang, Ji-Hai; Zhu, Yuan-Feng
2016-10-01
The technique of eliminating the higher-order modes in a few-mode optical fiber is proposed. The fiber is designed with a group of defect modes in the cladding. The higher-order modes in the fiber can be eliminated by bending the fiber to induce strong coupling between the defect modes and the higher-order modes. Numerical simulation shows the bending losses of the LP01 mode are lower than 1.5×10-4 dB/turn for the wavelength shorter than 1.625 μm. The proposed fiber can be bent multiple turns at small bending radius which are preferable for FTTH related applications.
Energy Technology Data Exchange (ETDEWEB)
Erikson, R.L.
1983-12-01
The long-term stability of a sandstone reservoir is of primary importance to the success of compressed air energy storage (CAES) in aquifers. The purpose of this study was to: develop experimental techniques for the operation of the CAES Porous Media Flow Loop (PMFL), an apparatus designed to study the stability of porous media in subsurface geologic environments, conduct experiments in the PMFL designed to determine the effects of temperature, stress, and humidity on the stability of candidate CAES reservoir materials, provide support for the CAES field demonstration project in Pittsfield, Illinois, by characterizing the thermophysical stability of Pittsfield reservoir sandstone under simulated field conditions.
Dubin, D. H. E.
This chapter explores several aspects of the linear electrostatic normal modes of oscillation for a single-species non-neutral plasma in a Penning trap. Linearized fluid equations of motion are developed, assuming the plasma is cold but collisionless, which allow derivation of the cold plasma dielectric tensor and the electrostatic wave equation. Upper hybrid and magnetized plasma waves in an infinite uniform plasma are described. The effect of the plasma surface in a bounded plasma system is considered, and the properties of surface plasma waves are characterized. The normal modes of a cylindrical plasma column are discussed, and finally, modes of spheroidal plasmas, and finite temperature effects on the modes, are briefly described.
Energy Technology Data Exchange (ETDEWEB)
Haque, Q. [Theoretical Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan); Zakir, U. [Department of Physics, University of Peshawar, Khyber Pakhtun Khwa 25000 (Pakistan); Department of Physics, University of Malakand, Khyber Pakhtun Khwa 18800 (Pakistan); Qamar, A. [Department of Physics, University of Peshawar, Khyber Pakhtun Khwa 25000 (Pakistan)
2015-12-15
Linear and nonlinear dynamics of electron temperature gradient mode along with parallel electron dynamics is investigated by considering hydrodynamic electrons and non-Maxwellian ions. It is noticed that the growth rate of η{sub e}-mode driven linear instability decreases by increasing the value of spectral index and increases by reducing the ion/electron temperature ratio along the magnetic field lines. The eigen mode dispersion relation is also found in the ballooning mode limit. Stationary solutions in the form of dipolar vortices are obtained for both circular and elliptic boundary conditions. It is shown that the dynamics of both circular and elliptic vortices changes with the inclusion of inhomogeneity and non-Maxwellian effects.
Haque, Q.; Zakir, U.; Qamar, A.
2015-12-01
Linear and nonlinear dynamics of electron temperature gradient mode along with parallel electron dynamics is investigated by considering hydrodynamic electrons and non-Maxwellian ions. It is noticed that the growth rate of ηe-mode driven linear instability decreases by increasing the value of spectral index and increases by reducing the ion/electron temperature ratio along the magnetic field lines. The eigen mode dispersion relation is also found in the ballooning mode limit. Stationary solutions in the form of dipolar vortices are obtained for both circular and elliptic boundary conditions. It is shown that the dynamics of both circular and elliptic vortices changes with the inclusion of inhomogeneity and non-Maxwellian effects.
An automatic mode-locked system for passively mode-locked fiber laser
Li, Sha; Xu, Jun; Chen, Guoliang; Mei, Li; Yi, Bo
2013-12-01
This paper designs and implements one kind of automatic mode-locked system. It can adjust a passively mode-locked fiber laser to keep steady mode-locked states automatically. So the unsteadiness of traditional passively mode-locked fiber laser can be avoided. The system transforms optical signals into electrical pulse signals and sends them into MCU after processing. MCU calculates the frequency of the signals and judges the state of the output based on a quick judgment algorithm. A high-speed comparator is used to check the signals and the comparison voltage can be adjusted to improve the measuring accuracy. Then by controlling two polarization controllers at an angle of 45degrees to each other, MCU extrudes the optical fibers to change the polarization until it gets proper mode-locked output. So the system can continuously monitor the output signal and get it back to mode-locked states quickly and automatically. States of the system can be displayed on the LCD and PC. The parameters of the steady mode-locked states can be stored into an EEPROM so that the system will get into mode-locked states immediately next time. Actual experiments showed that, for a 6.238MHz passively mode-locked fiber lasers, the system can get into steady mode-locked states automatically in less than 90s after starting the system. The expected lock time can be reduced to less than 20s after follow up improvements.
Stability of longitudinal modes in a bunched beam with mode coupling
International Nuclear Information System (INIS)
Satoh, K.
1981-06-01
In this paper we study a longitudinal coherent bunch instability in which the growth time is comparable to or less than the period of synchrotron oscillations. Both longitudinal and transverse bunch instabilities have been studied. In most treatments, however, the coherent force is assumed to be small and is treated as a perturbation compared with the synchrotron force. This makes the problem simpler because an individual synchrotron mode is decoupled. As bunch current increases, the coherent force is no longer small and the mode frequency shift becomes significant compared with the synchrotron frequency. Therefore in this case it is necessary to include coupling of the synchrotron modes. Recently a fast blow-up instability which comes from mode coupling was studied. Their method is to derive a dispersion relation for a bunched beam using the Vlasov equation and to analyze it as in a coasting beam. They showed that if mode coupling is included the Vlasov equation predicts a fast microwave instability with a stability condition similar to that for a coasting beam. In this paper we will partly follow their method and present a formalism which includes coupling between higher-order radial modes as well as coupling between synchrotron modes. The formalism is considered to be generalization of the Sacherer formalism without mode coupling. This theory predicts that instability is induced not only by coupling between different synchrotron modes, but also by coupling between positive and negative modes, since negative synchrotron modes are included in the theory in a natural manner. This formalism is to be used for a Gaussian bunch and a parabolic bunch, and is also useful for transverse problems
Li, Ruipeng; Khan, Hadayat Ullah; Payne, Marcia M.; Smilgies, Detlef Matthias; Anthony, John Edward; Amassian, Aram
2012-01-01
-ray scattering (GIWAXS) in an environmental chamber provides unique quantitative insights into the time-evolution of the concentration of the solution, the onset of nucleation, and the mode of growth of the organic semiconductor under varied drying conditions
Moving mode shape function approach for spinning disk and asymmetric disc brake squeal
Kang, Jaeyoung
2018-06-01
The solution approach of an asymmetric spinning disk under stationary friction loads requires the mode shape function fixed in the disk in the assumed mode method when the equations of motion is described in the space-fixed frame. This model description will be termed the 'moving mode shape function approach' and it allows us to formulate the stationary contact load problem in both the axisymmetric and asymmetric disk cases. Numerical results show that the eigenvalues of the time-periodic axisymmetric disk system are time-invariant. When the axisymmetry of the disk is broken, the positive real parts of the eigenvalues highly vary with the rotation of the disk in the slow speeds in such application as disc brake squeal. By using the Floquet stability analysis, it is also shown that breaking the axisymmetry of the disc alters the stability boundaries of the system.
Compressed air energy storage system reservoir size for a wind energy baseload power plant
Energy Technology Data Exchange (ETDEWEB)
Cavallo, A.J.
1996-12-31
Wind generated electricity can be transformed from an intermittent to a baseload resource using an oversized wind farm in conjunction with a compressed air energy storage (CAES) system. The size of the storage reservoir for the CAES system (solution mined salt cavern or porous media) as a function of the wind speed autocorrelation time (C) has been examined using a Monte Carlo simulation for a wind class 4 (wind power density 450 W m{sup -2} at 50 m hub height) wind regime with a Weibull k factor of 2.5. For values of C typically found for winds over the US Great Plains, the storage reservoir must have a 60 to 80 hour capacity. Since underground reservoirs account for only a small fraction of total system cost, this larger storage reservoir has a negligible effect on the cost of energy from the wind energy baseload system. 7 refs., 2 figs., 1 tab.
International Nuclear Information System (INIS)
Parsapour, Amir; Dehkordi, Behzad Mirzaeian; Moallem, Mehdi
2015-01-01
In applications in which the high torque per ampere at low speed and rated power at high speed are required, the continuous current method is the best solution. However, there is no report on calculating the core loss of SRM in continuous current mode of operation. Efficiency and iron loss calculation which are complex tasks in case of conventional mode of operation is even more involved in continuous current mode of operation. In this paper, the Switched Reluctance Motor (SRM) is modeled using finite element method and core loss and copper loss of SRM in discontinuous and continuous current modes of operation are calculated using improved analytical techniques to include the minor loop losses in continuous current mode of operation. Motor efficiency versus speed in both operation modes is obtained and compared. - Highlights: • Continuous current method for Switched Reluctance Motor (SRM) is explained. • An improved analytical technique is presented for SRM core loss calculation. • SRM losses in discontinuous and continuous current operation modes are presented. • Effect of mutual inductances on SRM performance is investigated
Energy Technology Data Exchange (ETDEWEB)
Parsapour, Amir, E-mail: amirparsapour@gmail.com [Department of Electrical Engineering, University of Isfahan, Isfahan (Iran, Islamic Republic of); Dehkordi, Behzad Mirzaeian, E-mail: mirzaeian@eng.ui.ac.ir [Department of Electrical Engineering, University of Isfahan, Isfahan (Iran, Islamic Republic of); Moallem, Mehdi, E-mail: moallem@cc.iut.ac.ir [Department of Electrical Engineering, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of)
2015-03-15
In applications in which the high torque per ampere at low speed and rated power at high speed are required, the continuous current method is the best solution. However, there is no report on calculating the core loss of SRM in continuous current mode of operation. Efficiency and iron loss calculation which are complex tasks in case of conventional mode of operation is even more involved in continuous current mode of operation. In this paper, the Switched Reluctance Motor (SRM) is modeled using finite element method and core loss and copper loss of SRM in discontinuous and continuous current modes of operation are calculated using improved analytical techniques to include the minor loop losses in continuous current mode of operation. Motor efficiency versus speed in both operation modes is obtained and compared. - Highlights: • Continuous current method for Switched Reluctance Motor (SRM) is explained. • An improved analytical technique is presented for SRM core loss calculation. • SRM losses in discontinuous and continuous current operation modes are presented. • Effect of mutual inductances on SRM performance is investigated.
A Class of Quasi-exact Solutions of Rabi Hamiltonian
International Nuclear Information System (INIS)
Pan Feng; Yao Youkun; Xie Mingxia; Han Wenjuan; Draayer, J.P.
2007-01-01
A class of quasi-exact solutions of the Rabi Hamiltonian, which describes a two-level atom interacting with a single-mode radiation field via a dipole interaction without the rotating-wave approximation, are obtained by using a wavefunction ansatz. Exact solutions for part of the spectrum are obtained when the atom-field coupling strength and the field frequency satisfy certain relations. As an example, the lowest exact energy level and the corresponding atom-field entanglement at the quasi-exactly solvable point are calculated and compared to results from the Jaynes-Cummings and counter-rotating cases of the Rabi Hamiltonian.
Congruent reduction and mode conversion in 4-dimensional plasmas
International Nuclear Information System (INIS)
Friedland, L.; Kaufman, A.N.
1987-04-01
Standard eikonal theory reduces, to N=1, the order of the system of equations underlying wave propagation in inhomogeneous plasmas. The condition for this remarkable reducibility is that only one eigenvalue of the unreduced NxN dispersion matrix D(k,x) vanishes at a time. If, however, two or more eigenvalues of D become simultaneously small, the geometric optics reduction scheme becomes singular. These regions are associated with linear mode conversion, and are described by higher order systems. A new reduction scheme based on congruent transformations of D is developed, and it is shown that, in ''degenerate'' plasma regions, a partial reduction of order is possible. The method comprises a constructive step-by-step procedure, which, in the most frequent (doubly) degenerate case, yields a second order system, describing the pairwise mode conversion problems, the solution of which in general geometry has been found recently
Boschi, Lapo
2006-10-01
I invert a large set of teleseismic phase-anomaly observations, to derive tomographic maps of fundamental-mode surface wave phase velocity, first via ray theory, then accounting for finite-frequency effects through scattering theory, in the far-field approximation and neglecting mode coupling. I make use of a multiple-resolution pixel parametrization which, in the assumption of sufficient data coverage, should be adequate to represent strongly oscillatory Fréchet kernels. The parametrization is finer over North America, a region particularly well covered by the data. For each surface-wave mode where phase-anomaly observations are available, I derive a wide spectrum of plausible, differently damped solutions; I then conduct a trade-off analysis, and select as optimal solution model the one associated with the point of maximum curvature on the trade-off curve. I repeat this exercise in both theoretical frameworks, to find that selected scattering and ray theoretical phase-velocity maps are coincident in pattern, and differ only slightly in amplitude.
Ge, Qingchun
2016-01-29
© 2016 American Chemical Society. Effective removal of As(III) from water by an oxalic acid complex with the formula of Na3[Cr(C2O4)3] (Na-Cr-OA) is demonstrated via an forward osmosis-membrane distillation (FO-MD) hybrid system in this study. Na-Cr-OA first proved its superiority as a draw solute with high water fluxes and negligible reverse fluxes in FO, then a systematic investigation of the Na-Cr-OA promoted FO process was conducted to ascertain the factors in As(III) removal. Relatively high water fluxes of 28 LMH under the FO mode and 74 LMH under the pressure retarded osmosis (PRO) mode were achieved when using a 1000 ppm As(III) solution as the feed and 1.0 M Na-Cr-OA as the draw solution at 60 °C. As(III) removal with a water recovery up to 21.6% (FO mode) and 48.3% (PRO mode) were also achieved in 2 h. An outstanding As(III) rejection with 30-3000 μg/L As(III) in the permeate was accomplished when As(III) feed solutions varied from 5 × 104 to 1 × 106 μg/L, superior to the best FO performance reported for As(III) removal. Incorporating MD into FO not only makes As(III) removal sustainable by reconcentrating the Na-Cr-OA solution simultaneously, but also reduces the As(III) concentration below 10 μg/L in the product water, meeting the WHO standard.
Ge, Qingchun; Han, Gang; Chung, Neal Tai-Shung
2016-01-01
© 2016 American Chemical Society. Effective removal of As(III) from water by an oxalic acid complex with the formula of Na3[Cr(C2O4)3] (Na-Cr-OA) is demonstrated via an forward osmosis-membrane distillation (FO-MD) hybrid system in this study. Na-Cr-OA first proved its superiority as a draw solute with high water fluxes and negligible reverse fluxes in FO, then a systematic investigation of the Na-Cr-OA promoted FO process was conducted to ascertain the factors in As(III) removal. Relatively high water fluxes of 28 LMH under the FO mode and 74 LMH under the pressure retarded osmosis (PRO) mode were achieved when using a 1000 ppm As(III) solution as the feed and 1.0 M Na-Cr-OA as the draw solution at 60 °C. As(III) removal with a water recovery up to 21.6% (FO mode) and 48.3% (PRO mode) were also achieved in 2 h. An outstanding As(III) rejection with 30-3000 μg/L As(III) in the permeate was accomplished when As(III) feed solutions varied from 5 × 104 to 1 × 106 μg/L, superior to the best FO performance reported for As(III) removal. Incorporating MD into FO not only makes As(III) removal sustainable by reconcentrating the Na-Cr-OA solution simultaneously, but also reduces the As(III) concentration below 10 μg/L in the product water, meeting the WHO standard.
Chemical analysis of zinc electroplating solutions by x-ray fluorescence spectrometry
International Nuclear Information System (INIS)
Jung, Sung-Mo; Cho, Young-Mo; Na, Han-Gil
2007-01-01
A quantitative analysis method used to analyze chlorine, iron and zinc in electroplating solutions, using X-ray spectrometry in atmospheric He mode, is proposed. The present research concerns the replacement of the conventional analyses of electroplating solutions with rapid and reproducible quantification using X-ray fluorescence spectrometer. An in-depth investigation conducted in the present study identifies the species present in the real electroplating solutions. XRD patterns and semi-quantitative results for the electroplating solutions show synthetic standards based on the compositional range of solutions by analyzing the electroplating solutions obtained in real processes. 28 calibration standard solutions are prepared by diluting liquid standard solutions certified by titration and ICP-OES analyses used to construct the XRF calibration curves for Cl, Fe and Zn. The suggested method showed satisfactory precision and accuracy in the analysis of electroplating solutions. The present study provides evidences that the proposed XRF spectrometry could be an alternative analytical method to replace the conventional techniques by comparing the uncertainties estimated for each method. (author)
A Refractive Index Sensor Based on the Resonant Coupling to Cladding Modes in a Fiber Loop
Reyes, Mauricio; Monzón-Hernández, David; Martínez-Ríos, Alejandro; Silvestre, Enrique; Díez, Antonio; Cruz, José Luis; Andrés, Miguel V.
2013-01-01
We report an easy-to-build, compact, and low-cost optical fiber refractive index sensor. It consists of a single fiber loop whose transmission spectra exhibit a series of notches produced by the resonant coupling between the fundamental mode and the cladding modes in a uniformly bent fiber. The wavelength of the notches, distributed in a wavelength span from 1,400 to 1,700 nm, can be tuned by adjusting the diameter of the fiber loop and are sensitive to refractive index changes of the external medium. Sensitivities of 170 and 800 nm per refractive index unit for water solutions and for the refractive index interval 1.40–1.442, respectively, are demonstrated. We estimate a long range resolution of 3 × 10−4 and a short range resolution of 2 × 10−5 for water solutions. PMID:23979478
Nonlinear stationary solutions of the Wigner and Wigner-Poisson equations
International Nuclear Information System (INIS)
Haas, F.; Shukla, P. K.
2008-01-01
Exact nonlinear stationary solutions of the one-dimensional Wigner and Wigner-Poisson equations in the terms of the Wigner functions that depend not only on the energy but also on position are presented. In this way, the Bernstein-Greene-Kruskal modes of the classical plasma are adapted for the quantum formalism in the phase space. The solutions are constructed for the case of a quartic oscillator potential, as well as for the self-consistent Wigner-Poisson case. Conditions for well-behaved physically meaningful equilibrium Wigner functions are discussed.
Stationary solutions and self-trapping in discrete quadratic nonlinear systems
DEFF Research Database (Denmark)
Bang, Ole; Christiansen, Peter Leth; Clausen, Carl A. Balslev
1998-01-01
We consider the simplest equations describing coupled quadratic nonlinear (chi((2))) systems, which each consists of a fundamental mode resonantly interacting with its second harmonic. Such discrete equations apply, e.g., to optics, where they can describe arrays of chi((2)) waveguides...... the nonintegrable dimer reduce to the discrete nonlinear Schrodinger (DNLS) equation with two degrees of freedom, which is integrable. We show how the stationary solutions to the two systems correspond to each other and how the self-trapped DNLS solutions gradually develop chaotic dynamics in the chi((2)) system...
Handling Do-Not-Know Answers : Exploring New Approaches in Online and Mixed-Mode Surveys
de Leeuw, Edith D.; Hox, Joop J.; Boevé, Anja
2016-01-01
An important decision in online and mixed-mode questionnaire design is if and how to include a “do-not-know” (DK) option. Mandatory response is often a default option, but methodologists have advised against this. Several solutions for the DK category are suggested. These include (1) not explicitly
International Nuclear Information System (INIS)
Cox, A.N.
1982-01-01
Double mode pulsation is a very pervasive phenomenon in stars all over the Hertzsprung-Russell diagram. In order of increasing radius, examples are: ZZ Ceti stars, the sun, the delta Scuti stars, RR Lyrae variables, the β Cephei variables and those related to them, Cepheids, and maybe even the Mira stars. These many modes have been interpreted as both radial and nonradial modes, but in many cases the actual mode has not been clearly identified. Yellow giants seem to be the most simple pulsators with a large majority of the RR Lyrae variables and Cepheids showing only one pulsation period. We limit this review to those very few cases for classical Cepheids and RR Lyrae variables which display two modes. For these we know many facts about these stars, but the actual cause of the pulsation in two modes simultaneously remains unknown
Perturbations and quasi-normal modes of black holes in Einstein-Aether theory
International Nuclear Information System (INIS)
Konoplya, R.A.; Zhidenko, A.
2007-01-01
We develop a new method for calculation of quasi-normal modes of black holes, when the effective potential, which governs black hole perturbations, is known only numerically in some region near the black hole. This method can be applied to perturbations of a wide class of numerical black hole solutions. We apply it to the black holes in the Einstein-Aether theory, a theory where general relativity is coupled to a unit time-like vector field, in order to observe local Lorentz symmetry violation. We found that in the non-reduced Einstein-Aether theory, real oscillation frequency and damping rate of quasi-normal modes are larger than those of Schwarzschild black holes in the Einstein theory
Energy Technology Data Exchange (ETDEWEB)
Richter, Andreas; Sokollik, Frank [Hochschule Merseburg (Germany). Fachbereich Informatik und Kommunikationssysteme
2012-07-01
Hardware-in-the-loop (HiL) is a method for testing and validating technical automation solutions based on virtual processes in a simulation environment. Applied to the automation of the interior air supply systems, preceded commissioning tests of the controller at a simulated system can be performed. These tests can be used for example to find logic errors in the program development, or to adjust the parameters of a controller. The adjustment of the parameters can be performed independent of the seasons by modifying the ambient climatic conditions. The parameters of the plants can be tested under dynamic conditions. The control mode can be visualized by starting up of load conditions at dynamic HVAC components and optimized if necessary. Within BMBF funded projects, a HiL solution was developed in a.NET environment. The coupling of simulation and control takes place via the bus systems CAN and BACnet. The elements of the simulation of air conditioners are implemented object-oriented in the programming language C, and are based on the solution of dynamic mass and energy balances. The features of HIL are implemented in a multi-client architecture. This includes primarily the simulation and communication. Other feature are implemented: import of virtual systems from a CAE system, adjustment of parameters of the simulation using structured sets of parameters, features for a distributed simulation of complex systems in the network, a tool for the dimensioning of controllers, chart and visualization features.
Instabilities with polyacrylamide solution in small and large aspect ratios Taylor-Couette systems
International Nuclear Information System (INIS)
Smieszek, M; Egbers, C; Crumeyrolle, O; Mutabazi, I
2008-01-01
We have investigated the stability of viscoelastic polyacrylamide solution in Taylor-Couette system with different aspect ratios. The first instability modes observed in a Taylor-Couette system with Γ = 10 were TVF and WVF, as for Newtonian fluid. At higher Taylor numbers moving vortices occur, a wavy mode with non-stationary vortex size. In the Taylor-Couette system with Γ = 45.9 we note a coexistence of various instability modes. In addition to TVF, counterpropagating waves developed at the transition from the base state flow. At higher Taylor number values Taylor vortices of different sizes occurred. Reduced amplitude Wavy vortex flow has also been observed.
Design of a compressed air energy storage system for hydrostatic wind turbines
Directory of Open Access Journals (Sweden)
Ammar E. Ali
2018-03-01
Full Text Available Integration of Compressed Air Energy Storage (CAES system with a wind turbine is critical in optimally harvesting wind energy given the fluctuating nature of power demands. Here we consider the design of a CAES for a wind turbine with hydrostatic powertrain. The design parameters of the CAES are determined based on simulation of the integrated system model for a combination of these parameter values, namely the compression ratios of the air compressors and the expanders and the air tank size. The results of the simulations were used to choose the best design parameters, which would produce the best stable performance through increased energy output of the integrated CAES and wind turbine based on the intermittent wind profile. Simulation results for a 600 kW rated power wind turbine with integrated CAES indicate that increasing the tank size and compression ratio will improve the overall power quality through increased energy output up to a limit beyond which the power quality exhibits only marginal improvement.
Collector modulation in high-voltage bipolar transistor in the saturation mode: Analytical approach
Dmitriev, A. P.; Gert, A. V.; Levinshtein, M. E.; Yuferev, V. S.
2018-04-01
A simple analytical model is developed, capable of replacing the numerical solution of a system of nonlinear partial differential equations by solving a simple algebraic equation when analyzing the collector resistance modulation of a bipolar transistor in the saturation mode. In this approach, the leakage of the base current into the emitter and the recombination of non-equilibrium carriers in the base are taken into account. The data obtained are in good agreement with the results of numerical calculations and make it possible to describe both the motion of the front of the minority carriers and the steady state distribution of minority carriers across the collector in the saturation mode.
Inter-comb synchronization by mode-to-mode locking
Chun, Byung Jae; Kim, Young-Jin; Kim, Seung-Woo
2016-08-01
Two combs of fiber femtosecond lasers are synchronized through the optical frequency reference created by injection-locking of a diode laser to a single comb mode. Maintaining a mHz-level narrow linewidth, the optical frequency reference permits two combs to be stabilized by mode-to-mode locking with a relative stability of 1.52 × 10-16 at 10 s with a frequency slip of 2.46 mHz. This inter-comb synchronization can be utilized for applications such as dual-comb spectroscopy or ultra-short pulse synthesis without extra narrow-linewidth lasers.
NASA Center for Astronomy Education: Building a Community of Practice
Brissenden, Gina; Prather, E. E.; Slater, T. F.; Greene, W. M.; Thaller, M.; Alvidrez, R.
2007-12-01
The NASA Center for Astronomy Education (CAE) is devoted to the professional development of introductory college astronomy instructors teaching at community colleges. The primary goal is building a "community of practice." Evaluation results suggest this community of practice model is effective at improving instructional practices, particularly in settings where instructors feel isolated from their peers. For community college faculty this isolation can be quite real. Many are the only astronomer, if not the only scientist, at their institution. In addition, they may be adjunct instructors who have no office, no institutional email address, nor appear in the campus directory. CAE works to prevent this sense of isolation by building both actual and virtual communities for these instructors, as well as provide actual and virtual professional development opportunities. CAE's major effort is providing multi-tiered "Teaching Excellence Workshops" offered at national and regional venues. Recently added to our workshop offerings is a Tier II, or advanced, workshop for instructors who have attended a previous Teaching Excellence Workshop. The focus of the Tier II workshops is on implementation issues. In addition, we are now also offering a workshop exclusively for post-docs, graduates, and undergraduate students. Ongoing support is offered through the CAE website. Instructors can learn about, and register for, upcoming workshops. They can engage in discussions about educational issues and share best practices with peers using the moderated discussion group Astrolrner@CAE. CAE also provides an updated article "This Month's Teaching Strategy” which is a reflection on teaching strategies discussed in the workshops. Instructors can also find their peers through the online map of US community colleges offering introductory astronomy courses. Lastly, CAE Regional Teaching Exchanges facilitate local, and sustained, community building. CAE is supported by the NASA/JPL Navigator
Finite toroidal flow generated by unstable tearing mode in a toroidal plasma
Energy Technology Data Exchange (ETDEWEB)
Hao, G. Z., E-mail: haogz@swip.ac.cn; Wang, A. K.; Xu, Y. H.; He, H. D.; Xu, M.; Qu, H. P.; Peng, X. D.; Xu, J. Q.; Qiu, X. M. [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041 (China); Liu, Y. Q. [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Sun, Y. [Institute of Plasma Physics, Chinese Academic of Sciences, P.O. Box 1126, Hefei 230031 (China); Cui, S. Y. [School of Mathematics and Statistics Science, Ludong University, Yantai 264025 (China)
2014-12-15
The neoclassical toroidal plasma viscosity torque and electromagnetic torque, generated by tearing mode (TM) in a toroidal plasma, are numerically investigated using the MARS-Q code [Liu et al., Phys. Plasmas 20, 042503 (2013)]. It is found that an initially unstable tearing mode can intrinsically drive a toroidal plasma flow resulting in a steady state solution, in the absence of the external momentum input and external magnetic field perturbation. The saturated flow is in the order of 0.5%ω{sub A} at the q=2 rational surface in the considered case, with q and ω{sub A} being the safety factor and the Alfven frequency at the magnetic axis, respectively. The generation of the toroidal flow is robust, being insensitive to the given amplitude of the perturbation at initial state. On the other hand, the flow amplitude increases with increasing the plasma resistivity. Furthermore, the initially unstable tearing mode is fully stabilized by non-linear interaction with the self-generated toroidal flow.
Solution of diffusion equation in deformable spheroids
Energy Technology Data Exchange (ETDEWEB)
Ayyoubzadeh, Seyed Mohsen [Department of Energy Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Safari, Mohammad Javad, E-mail: iFluka@gmail.com [Department of Energy Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Vosoughi, Naser [Department of Energy Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of)
2011-05-15
Research highlights: > Developing an explicit solution for the diffusion equation in spheroidal geometry. > Proving an orthogonality relation for spheroidal eigenfunctions. > Developing a relation for the extrapolation distance in spheroidal geometry. > Considering the sphere and slab as limiting cases for a spheroid. > Cross-validation of the analytical solution with Monte Carlo simulations. - Abstract: The time-dependent diffusion of neutrons in a spheroid as a function of the focal distance has been studied. The solution is based on an orthogonal basis and an extrapolation distanced related boundary condition for the spheroidal geometry. It has been shown that spheres and disks are two limiting cases for the spheroids, for which there is a smooth transition for the systems properties between these two limits. Furthermore, it is demonstrated that a slight deformation from a sphere does not affect the fundamental mode properties, to the first order. The calculations for both multiplying and non-multiplying media have been undertaken, showing good agreement with direct Monte Carlo simulations.
The H-mode Pedestal and Edge Localized Modes in NSTX
International Nuclear Information System (INIS)
Maingi, R.; Fredrickson, E.D.; Menard, J.E.; Nishino, N.; Roquemore, A.L.; Sabbagh, S.A.; Tritz, K.
2004-01-01
The research program of the National Spherical Torus Experiment (NSTX) routinely utilizes the H-mode confinement regime to test and extend beta and pulse length limits. As in conventional aspect ratio tokamaks, NSTX observes a variety of edge localized modes (ELMs) in H-mode. Hence a significant part of the research program is dedicated to ELMs studies
Space-time slicing in Horndeski theories and its implications for non-singular bouncing solutions
Ijjas, Anna
2018-02-01
In this paper, we show how the proper choice of gauge is critical in analyzing the stability of non-singular cosmological bounce solutions based on Horndeski theories. We show that it is possible to construct non-singular cosmological bounce solutions with classically stable behavior for all modes with wavelengths above the Planck scale where: (a) the solution involves a stage of null-energy condition violation during which gravity is described by a modification of Einstein's general relativity; and (b) the solution reduces to Einstein gravity both before and after the null-energy condition violating stage. Similar considerations apply to galilean genesis scenarios.
International Nuclear Information System (INIS)
Lee, Jeong Min; Kim, Se Hyung; Han, Joon Koo; Sohn, Kyu Li; Choi, Byung Ihn
2005-01-01
The purpose of this study was to validate the saline-enhanced bipolar radiofrequency ablation (RFA) technique using a perfused electrode to increase RF-created coagulation necrosis, to compare that technique with monopolar RFAs and to find appropriate concentrations and volumes of perfused NaCl solution for the bipolar RFA. A total of 90 ablations were performed in explanted bovine livers. In the initial experiments to determine appropriate conditions for bipolar RFA, we created five thermal ablation zones in each condition, with instillations of varied concentrations (0.9-36%) or injection rates (30 mL/hr-120 mL/hr) of NaCl solution. After placement of one or two 16-gauge open-perfused electrodes into bovine livers, the NaCl solution was instilled into the tissue through the electrode. In the second part of the study, 10 ablation zones were created using one or two perfused electrodes for each of five groups under different conditions: a conventional monopolar mode with 0.9% NaCl solution (group A) or with 6% NaCl solution (group B), a simultaneous monopolar mode with 6% NaCl solution (group C) and a bipolar mode with 6% NaCl solution (groups D and E). RF was applied to each electrode for 20 min in groups A, B, C, and E, or for 10 min in group D. During RFA, we measured the tissue temperature 15 mm from the electrode. The temperature changes during the RFA and the dimensions of the ablation zones were compared among the groups. Bipolar RFA created larger short-axis diameters of coagulation necrosis with 6% NaCl solution (35.8 ± 15 mm) than with 0.9% NaCl solution (17 ± 9.7 mm) (P 0.05): 31.0 ± 5.4 mm (group A); 28.8 ± 3.8 mm (group B); 25.5 ± 6.4 mm (group C); 32.6 ± 4.2 mm (group D); 49.4 ± 5.0 mm (group E). Bipolar RFA with instillation of 6% NaCl solution through an open perfusion system demonstrates better efficacy in creating a larger ablation zone than does conventional or simultaneous monopolar modes at the various times examined. Therefore
A Minimal Model to Explore the Influence of Distant Modes on Mode-Coupling Instabilities
Kruse, Sebastian; Hoffmann, Norbert
2010-09-01
The phenomenon of mode-coupling instability is one of the most frequently explored mechanisms to explain self-excited oscillation in sliding systems with friction. A mode coupling instability is usually due to the coupling of two modes. However, further modes can have an important influence on the coupling of two modes. This work extends a well-known minimal model to describe mode-coupling instabilities in order to explore the influence of a distant mode on the classical mode-coupling pattern. This work suggests a new minimal model. The model is explored and it is shown that a third mode can have significant influence on the classical mode-coupling instabilities where two modes are coupling. Different phenomena are analysed and it is pointed out that distant modes can only be ignored in very special cases and that the onset friction-induced oscillations can even be very sensitive to minimal variation of a distant mode. Due to the chosen academic minimal-model and the abandonment of a complex Finite-Element model the insight stays rather phenomenological but a better understanding of the mode-coupling mechnanism can be gained.
Karlin, Ilya
2018-04-01
Derivation of the dynamic correction to Grad's moment system from kinetic equations (regularized Grad's 13 moment system, or R13) is revisited. The R13 distribution function is found as a superposition of eight modes. Three primary modes, known from the previous derivation (Karlin et al. 1998 Phys. Rev. E 57, 1668-1672. (doi:10.1103/PhysRevE.57.1668)), are extended into the nonlinear parameter domain. Three essentially nonlinear modes are identified, and two ghost modes which do not contribute to the R13 fluxes are revealed. The eight-mode structure of the R13 distribution function implies partition of R13 fluxes into two types of contributions: dissipative fluxes (both linear and nonlinear) and nonlinear streamline convective fluxes. Physical interpretation of the latter non-dissipative and non-local in time effect is discussed. A non-perturbative R13-type solution is demonstrated for a simple Lorentz scattering kinetic model. The results of this study clarify the intrinsic structure of the R13 system. This article is part of the theme issue `Hilbert's sixth problem'.
RESONANT ABSORPTION OF AXISYMMETRIC MODES IN TWISTED MAGNETIC FLUX TUBES
Energy Technology Data Exchange (ETDEWEB)
Giagkiozis, I.; Verth, G. [Solar Plasma Physics Research Centre, School of Mathematics and Statistics, University of Sheffield, Hounsfield Road, Hicks Building, Sheffield, S3 7RH (United Kingdom); Goossens, M.; Doorsselaere, T. Van [Centre for mathematical Plasma Astrophysics, Mathematics Department, KU Leuven, Celestijnenlaan 200B bus 2400, B-3001 Leuven (Belgium); Fedun, V. [Department of Automatic Control and Systems Engineering, University of Sheffield, Mappin Street, Amy Johnson Building, Sheffield, S1 3JD (United Kingdom)
2016-06-01
It has been shown recently that magnetic twist and axisymmetric MHD modes are ubiquitous in the solar atmosphere, and therefore the study of resonant absorption for these modes has become a pressing issue because it can have important consequences for heating magnetic flux tubes in the solar atmosphere and the observed damping. In this investigation, for the first time, we calculate the damping rate for axisymmetric MHD waves in weakly twisted magnetic flux tubes. Our aim is to investigate the impact of resonant damping of these modes for solar atmospheric conditions. This analytical study is based on an idealized configuration of a straight magnetic flux tube with a weak magnetic twist inside as well as outside the tube. By implementing the conservation laws derived by Sakurai et al. and the analytic solutions for weakly twisted flux tubes obtained recently by Giagkiozis et al. we derive a dispersion relation for resonantly damped axisymmetric modes in the spectrum of the Alfvén continuum. We also obtain an insightful analytical expression for the damping rate in the long wavelength limit. Furthermore, it is shown that both the longitudinal magnetic field and the density, which are allowed to vary continuously in the inhomogeneous layer, have a significant impact on the damping time. Given the conditions in the solar atmosphere, resonantly damped axisymmetric modes are highly likely to be ubiquitous and play an important role in energy dissipation. We also suggest that, given the character of these waves, it is likely that they have already been observed in the guise of Alfvén waves.
A Two-Mode Mean-Field Optimal Switching Problem for the Full Balance Sheet
Directory of Open Access Journals (Sweden)
Boualem Djehiche
2014-01-01
a two-mode optimal switching problem of mean-field type, which can be described by a system of Snell envelopes where the obstacles are interconnected and nonlinear. The main result of the paper is a proof of a continuous minimal solution to the system of Snell envelopes, as well as the full characterization of the optimal switching strategy.
Time-periodic solutions of the Benjamin-Ono equation
Energy Technology Data Exchange (ETDEWEB)
Ambrose , D.M.; Wilkening, Jon
2008-04-01
We present a spectrally accurate numerical method for finding non-trivial time-periodic solutions of non-linear partial differential equations. The method is based on minimizing a functional (of the initial condition and the period) that is positive unless the solution is periodic, in which case it is zero. We solve an adjoint PDE to compute the gradient of this functional with respect to the initial condition. We include additional terms in the functional to specify the free parameters, which, in the case of the Benjamin-Ono equation, are the mean, a spatial phase, a temporal phase and the real part of one of the Fourier modes at t = 0. We use our method to study global paths of non-trivial time-periodic solutions connecting stationary and traveling waves of the Benjamin-Ono equation. As a starting guess for each path, we compute periodic solutions of the linearized problem by solving an infinite dimensional eigenvalue problem in closed form. We then use our numerical method to continue these solutions beyond the realm of linear theory until another traveling wave is reached (or until the solution blows up). By experimentation with data fitting, we identify the analytical form of the solutions on the path connecting the one-hump stationary solution to the two-hump traveling wave. We then derive exact formulas for these solutions by explicitly solving the system of ODE's governing the evolution of solitons using the ansatz suggested by the numerical simulations.
Time-periodic solutions of the Benjamin-Ono equation
International Nuclear Information System (INIS)
Ambrose, D.M.; Wilkening, Jon
2008-01-01
We present a spectrally accurate numerical method for finding non-trivial time-periodic solutions of non-linear partial differential equations. The method is based on minimizing a functional (of the initial condition and the period) that is positive unless the solution is periodic, in which case it is zero. We solve an adjoint PDE to compute the gradient of this functional with respect to the initial condition. We include additional terms in the functional to specify the free parameters, which, in the case of the Benjamin-Ono equation, are the mean, a spatial phase, a temporal phase and the real part of one of the Fourier modes at t = 0. We use our method to study global paths of non-trivial time-periodic solutions connecting stationary and traveling waves of the Benjamin-Ono equation. As a starting guess for each path, we compute periodic solutions of the linearized problem by solving an infinite dimensional eigenvalue problem in closed form. We then use our numerical method to continue these solutions beyond the realm of linear theory until another traveling wave is reached (or until the solution blows up). By experimentation with data fitting, we identify the analytical form of the solutions on the path connecting the one-hump stationary solution to the two-hump traveling wave. We then derive exact formulas for these solutions by explicitly solving the system of ODE's governing the evolution of solitons using the ansatz suggested by the numerical simulations
Quasinormal modes of BTZ black hole and Hawking-like radiation in graphene
Energy Technology Data Exchange (ETDEWEB)
Kandemir, B.S.; Ertem, Uemit [Department of Physics, Ankara University, Faculty of Sciences, 06100, Tandogan-Ankara (Turkey)
2017-04-15
The Banados-Teitelboim-Zanelli (BTZ) black hole model corresponds to a solution of (2+1)-dimensional Einstein gravity with negative cosmological constant, and by a conformal rescaling its metric can be mapped onto the hyperbolic pseudosphere surface (Beltrami trumpet) with negative curvature. Beltrami trumpet shaped graphene sheets have been predicted to emit Hawking radiation that is experimentally detectable by a scanning tunnelling microscope. Here, for the first time we present an analytical algorithm that allows variational solutions to the Dirac Hamiltonian of graphene pseudoparticles in BTZ black hole gravitational field by using an approach based on the formalism of pseudo-Hermitian Hamiltonians within a discrete-basis-set method. We show that our model not only reproduces the exact results for the real part of quasinormal mode frequencies of (2+1)-dimensional spinless BTZ black hole, but also provides analytical results for the real part of quasinormal modes of spinning BTZ black hole, and also offers some predictions for the observable effects with a view to gravity-like phenomena in a curved graphene sheet. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Accurate mode characterization of two-mode optical fibers by in-fiber acousto-optics.
Alcusa-Sáez, E; Díez, A; Andrés, M V
2016-03-07
Acousto-optic interaction in optical fibers is exploited for the accurate and broadband characterization of two-mode optical fibers. Coupling between LP 01 and LP 1m modes is produced in a broadband wavelength range. Difference in effective indices, group indices, and chromatic dispersions between the guided modes, are obtained from experimental measurements. Additionally, we show that the technique is suitable to investigate the fine modes structure of LP modes, and some other intriguing features related with modes' cut-off.
Mode-mode coupling theory of itinerant electron antiferromagnetism in superconducting state
International Nuclear Information System (INIS)
Fujimoto, Yukinobu; Miyake, Kazumasa
2012-01-01
It has been considered since the first discovery of a high-T c cuprate that an antiferromagnetic (AF) state and a superconducting (SC) state are separated in it. However, it is very intriguing that the coexistence of the AF and SC states has recently been observed in HgBa 2 Ca 4 Cu 5 O 12+ (Hg-1245). Moreover, it is very novel that this coexistence of these two states appears if the SC-transition temperature T c is higher than the AF-transition temperature T N . The mode-mode coupling theory can provide a clear elucidation of this novel phenomenon. A key point of this theory is that the AF susceptibility consists of the random-phase-approximation (RPA) term and the mode-mode coupling one. The RPA term works to make a positive contribution to the emergence of the antiferromagnetic critical point (AF-CP). In contrast, the mode-mode coupling term works to make a negative contribution to the emergence of the AF-CP. However, the growth of the SC-gap function in the d x 2 -y 2 -wave SC state works to suppress the negative contribution of the mode-mode coupling term to the emergence of the AF-CP. Moreover, the effect of SC fluctuations near the SC-transition temperature T c suppresses the mode-mode coupling term of the AF susceptibility that works to hinder the AF ordering. For these two reasons, there is a possibility that the d x 2 -y 2 -wave SC state is likely to promote the emergence of the AF-CP. Namely, the appearance of the above-mentioned novel coexistence of the AF and SC states observed in Hg-1245 can be explained qualitatively on the basis of this idea.
850-nm hybrid fiber/free-space optical communications using orbital angular momentum modes
DEFF Research Database (Denmark)
Jurado-Navas, Antonio; Tatarczak, Anna; Lu, Xiaofeng
2015-01-01
Light beams can carry orbital angular momentum (OAM) associated to the helicity of their phasefronts. These OAM modes can be employed to encode information onto a laser beam for transmitting not only in a fiber link but also in a free-space optical (FSO) one. Regarding this latter scenario, FSO...... communications are considered as an alternative and promising mean complementing the traditional optical communications in many applications where the use of fiber cable is not justified. This next generation FSO communication systems have attracted much interest recently, and the inclusion of beams carrying OAM...... modes can be seen as an efficient solution to increase the capacity and the security in the link. In this paper, we discuss an experimental demonstration of a proposal for next generation FSO communication system where a light beam carrying different OAM modes and affected by M turbulence is coupled...
Pulse-forming and line-broadening in AM mode locking of the TEA-CO2laser
Witteman, W.J.; Olbertz, A.H.M.
1977-01-01
The present paper describes AM mode locking for homogeneously broadened systems, a procedure for measuring linewidths under laser conditions, and finally, experimental results for a 1-atm CO2laser. Working in the frequency domain, analytic solutions are given for the pulse bandwidth and pulse shape
IMF-Slices for GPR Data Processing Using Variational Mode Decomposition Method
Directory of Open Access Journals (Sweden)
Xuebing Zhang
2018-03-01
Full Text Available Using traditional time-frequency analysis methods, it is possible to delineate the time-frequency structures of ground-penetrating radar (GPR data. A series of applications based on time-frequency analysis were proposed for the GPR data processing and imaging. With respect to signal processing, GPR data are typically non-stationary, which limits the applications of these methods moving forward. Empirical mode decomposition (EMD provides alternative solutions with a fresh perspective. With EMD, GPR data are decomposed into a set of sub-components, i.e., the intrinsic mode functions (IMFs. However, the mode-mixing effect may also bring some negatives. To utilize the IMFs’ benefits, and avoid the negatives of the EMD, we introduce a new decomposition scheme termed variational mode decomposition (VMD for GPR data processing for imaging. Based on the decomposition results of the VMD, we propose a new method which we refer as “the IMF-slice”. In the proposed method, the IMFs are generated by the VMD trace by trace, and then each IMF is sorted and recorded into different profiles (i.e., the IMF-slices according to its center frequency. Using IMF-slices, the GPR data can be divided into several IMF-slices, each of which delineates a main vibration mode, and some subsurface layers and geophysical events can be identified more clearly. The effectiveness of the proposed method is tested using synthetic benchmark signals, laboratory data and the field dataset.
A comprehensive spectral theory of zonal-mode dynamics in trapped electron mode turbulence
International Nuclear Information System (INIS)
Terry, P.W.; Gatto, R.; Baver, D.A.; Fernandez, E.
2005-01-01
A comprehensive, self-consistent theory for spectral dynamics in trapped electron mode (TEM) turbulence offers critical new understanding and insights into zonal-mode physics. This theory shows that 1) zonal mode structure, anisotropy, excitation, and temporal behavior arise at and from the interface of nonlinear advection and linear wave properties; 2) waves induce a marked spectral energy-transfer anisotropy that preferentially drives zonal modes relative to non zonal modes; 3) triplet correlations involving density (as opposed to those involving only flow) mediate the dominant energy transfer at long wavelengths; 4) energy transfer becomes inverse in the presence of wave anisotropy, where otherwise it is forward; 5) zonal-mode excitation is accompanied by excitation of a spectrum of damped eigenmodes, making zonal modes nonlinearly damped; and 6) the combination of anisotropic transfer to zonal modes and their nonlinear damping make this the dominant saturation mechanism for TEM turbulence. This accounts for the reduction of turbulence level by zonal modes, not zonal-flow ExB shearing. (author)
Geometric phases in astigmatic optical modes of arbitrary order
International Nuclear Information System (INIS)
Habraken, Steven J. M.; Nienhuis, Gerard
2010-01-01
The transverse spatial structure of a paraxial beam of light is fully characterized by a set of parameters that vary only slowly under free propagation. They specify bosonic ladder operators that connect modes of different orders, in analogy to the ladder operators connecting harmonic-oscillator wave functions. The parameter spaces underlying sets of higher-order modes are isomorphic to the parameter space of the ladder operators. We study the geometry of this space and the geometric phase that arises from it. This phase constitutes the ultimate generalization of the Gouy phase in paraxial wave optics. It reduces to the ordinary Gouy phase and the geometric phase of nonastigmatic optical modes with orbital angular momentum in limiting cases. We briefly discuss the well-known analogy between geometric phases and the Aharonov-Bohm effect, which provides some complementary insights into the geometric nature and origin of the generalized Gouy phase shift. Our method also applies to the quantum-mechanical description of wave packets. It allows for obtaining complete sets of normalized solutions of the Schroedinger equation. Cyclic transformations of such wave packets give rise to a phase shift, which has a geometric interpretation in terms of the other degrees of freedom involved.
International Nuclear Information System (INIS)
Li Jiangfan; Jiang Zongfu; Xiao Fuliang; Huang Chunjia
2005-01-01
The dynamics of a generalized non-degenerate optical parametric down-conversion interaction whose Hamiltonian includes an arbitrary time-dependent driving part and a two-mode coupled part is studied by adopting the Lewis-Riesenfeld invariant theory. The closed formulae for the evolution of the quantum states and the evolution operators of the system are obtained. It is shown that various generalized squeezed states arise naturally in the process, and the two-mode squeezed effect is independent of the driving part. An explicitly analytical solution of the Schroedinger equation is further derived as the classical generalized force acting on each mode and the coupling of the two modes both have harmonic time dependences. This solution is found to be in agreement with previous research in special cases