Classification of methods for measuring current-voltage characteristics of semiconductor devices

Directory of Open Access Journals (Sweden)

Iermolenko Ia. O.

2014-06-01

Full Text Available It is shown that computer systems for measuring current-voltage characteristics are very important for semiconductor devices production. The main criteria of efficiency of such systems are defined. It is shown that efficiency of such systems significantly depends on the methods for measuring current-voltage characteristics of semiconductor devices. The aim of this work is to analyze existing methods for measuring current-voltage characteristics of semiconductor devices and to create the classification of these methods in order to specify the most effective solutions in terms of defined criteria. To achieve this aim, the most common classifications of methods for measuring current-voltage characteristics of semiconductor devices and their main disadvantages are considered. Automated and manual, continuous, pulse, mixed, isothermal and isodynamic methods for measuring current-voltage characteristics are analyzed. As a result of the analysis and generalization of existing methods the next classification criteria are defined: the level of automation, the form of measurement signals, the condition of semiconductor device during the measurements, and the use of mathematical processing of the measurement results. With the use of these criteria the classification scheme of methods for measuring current-voltage characteristics of semiconductor devices is composed and the most effective methods are specified.

Analysis for trace mercury concentration. I. Critical evaluation of current procedures. II. A proposed method for determination by instrumental neutron activation analysis

International Nuclear Information System (INIS)

Litman, R.

1975-01-01

Current methods of sample pretreatments, digestion, lyophilization and extraction, have been found to lead to considerable loss of mercury, at an initial mercury concentration of 1 μg/g, and less. Storage of solutions of mercury at concentrations of less than 1 μg/ml, in glass, Teflon and polyethylene containers, leads to losses by adsorption. Electrochemical reduction of mercury to the metal, and subsequent volatilization, is postulated as the mechanism of loss from the samples studied during lyophilization. A method of instrumental neutron activation analysis, which obviates the above pretreatments, has been developed for mercury concentrations as low as 1 ng/ml

The comparative analysis of the current-meter method and the pressure-time method used for discharge measurements in the Kaplan turbine penstocks

Science.gov (United States)

Adamkowski, A.; Krzemianowski, Z.

2012-11-01

The paper presents experiences gathered during many years of utilizing the current-meter and pressure-time methods for flow rate measurements in many hydropower plants. The integration techniques used in these both methods are different from the recommendations contained in the relevant international standards, mainly from the graphical and arithmetical ones. The results of the comparative analysis of both methods applied at the same time during the hydraulic performance tests of two Kaplan turbines in one of the Polish hydropower plant are presented in the final part of the paper. In the case of the pressure-time method application, the concrete penstocks of the tested turbines required installing a special measuring instrumentation inside the penstock. The comparison has shown a satisfactory agreement between the results of discharge measurements executed using the both considered methods. Maximum differences between the discharge values have not exceeded 1.0 % and the average differences have not been greater than 0.5 %.

The comparative analysis of the current-meter method and the pressure-time method used for discharge measurements in the Kaplan turbine penstocks

International Nuclear Information System (INIS)

Adamkowski, A; Krzemianowski, Z

2012-01-01

The paper presents experiences gathered during many years of utilizing the current-meter and pressure-time methods for flow rate measurements in many hydropower plants. The integration techniques used in these both methods are different from the recommendations contained in the relevant international standards, mainly from the graphical and arithmetical ones. The results of the comparative analysis of both methods applied at the same time during the hydraulic performance tests of two Kaplan turbines in one of the Polish hydropower plant are presented in the final part of the paper. In the case of the pressure-time method application, the concrete penstocks of the tested turbines required installing a special measuring instrumentation inside the penstock. The comparison has shown a satisfactory agreement between the results of discharge measurements executed using the both considered methods. Maximum differences between the discharge values have not exceeded 1.0 % and the average differences have not been greater than 0.5 %.

Quantitative pulsed eddy current analysis

International Nuclear Information System (INIS)

Morris, R.A.

1975-01-01

The potential of pulsed eddy current testing for furnishing more information than conventional single-frequency eddy current methods has been known for some time. However, a fundamental problem has been analyzing the pulse shape with sufficient precision to produce accurate quantitative results. Accordingly, the primary goal of this investigation was to: demonstrate ways of digitizing the short pulses encountered in PEC testing, and to develop empirical analysis techniques that would predict some of the parameters (e.g., depth) of simple types of defect. This report describes a digitizing technique using a computer and either a conventional nuclear ADC or a fast transient analyzer; the computer software used to collect and analyze pulses; and some of the results obtained. (U.S.)

Analysis of strain distribution and critical current of superconductors based on a strain-critical current measurement system

International Nuclear Information System (INIS)

Liu Fang; Wu Yu; Long Feng

2010-01-01

Based on Pacman device which is widely used to investigate the axial strain dependence of the critical current in superconductors, the finite element analysis method is employed to carry out the force analysis of the spring and the superconducting strand, thereby the axial and lateral strain distributions of the superconducting strand are obtained. According to the two extreme assumptions(low inter-filament resistance and high inter-filament resistance), the effects of the strain homogeneity at the cross section of the superconductor on the critical current is analyzed combined with the Nb 3 Sn deviatoric strain-critical current scaling law. (authors)

Lightning Return Stroke Current Analysis Using Electromagnetic Models and the 3D-FDTD Method

Directory of Open Access Journals (Sweden)

Kaddour Arzag

2017-03-01

Full Text Available The three dimensions finite difference time domain method (3D-FDTD is employed to calculate lightning return stoke current distributions in a vertical lightning channel. The latter is excited at its bottom by a lumped current source above a flat perfectly conducting ground. In this study four lightning return stroke electromagnetic models are used. The calculating approach, which is based on Taflove formulation of the 3D-FDTD method combined to the UPML boundary conditions, is implemented on Matlab environment. For validation needs, the obtained lightning return stroke space and time distributions are compared with others taken from specialized literature.

Leakage current analysis of single-phase transformer-less grid-connected PV inverters

DEFF Research Database (Denmark)

Ma, Lin; Kerekes, Tamas; Teodorescu, Remus

2016-01-01

Transformer-less string PV inverter is getting more and more widely utilized due to its higher efficiency, smaller volume and weight. However, without the galvanic isolation, the leakage current limitation and operation safety became the key issues of transformer-less inverters. This paper...... simplifies the leakage current generation circuit model and presents a leakage current estimation method both in real time and frequency domain. It shows that the leakage current is related to the circuit stray parameters, output filter and common mode voltage. Furthermore, with the proposed analysis method......, the leakage current generation of H-bridge with different modulation methods and HERIC inverter are discussed individually. At last, the presented method has been verified via simulation....

Three-Phase Harmonic Analysis Method for Unbalanced Distribution Systems

Directory of Open Access Journals (Sweden)

Jen-Hao Teng

2014-01-01

Full Text Available Due to the unbalanced features of distribution systems, a three-phase harmonic analysis method is essential to accurately analyze the harmonic impact on distribution systems. Moreover, harmonic analysis is the basic tool for harmonic filter design and harmonic resonance mitigation; therefore, the computational performance should also be efficient. An accurate and efficient three-phase harmonic analysis method for unbalanced distribution systems is proposed in this paper. The variations of bus voltages, bus current injections and branch currents affected by harmonic current injections can be analyzed by two relationship matrices developed from the topological characteristics of distribution systems. Some useful formulas are then derived to solve the three-phase harmonic propagation problem. After the harmonic propagation for each harmonic order is calculated, the total harmonic distortion (THD for bus voltages can be calculated accordingly. The proposed method has better computational performance, since the time-consuming full admittance matrix inverse employed by the commonly-used harmonic analysis methods is not necessary in the solution procedure. In addition, the proposed method can provide novel viewpoints in calculating the branch currents and bus voltages under harmonic pollution which are vital for harmonic filter design. Test results demonstrate the effectiveness and efficiency of the proposed method.

Analysis of unbalanced sensor in eddy current method of non destructive testing

International Nuclear Information System (INIS)

Chegodaev, V.V.

2001-01-01

Different types of sensors are used in eddy current method of non-destructive testing. The choosing of sensor type depends on control object. Different types of sensors can have the same schemes of cut-in in device for formation of information signal. The most common scheme of sensor cut-in is presented. The calculation of output voltage when the sensor is on a segment of the control object, which has not defect is made. The conditions of balancing are adduced and it was shown that the balancing of sensor is very difficult. The methods of compensation or account of voltage of an imbalance are indicated. (author)

Current status of safety analysis report for ANPP

International Nuclear Information System (INIS)

Amirjanyan, A.

1999-01-01

Current situation concerning Armenian NPP safety analysis report is considered within the frame of accepted safety practice. Licensing procedure is being developed. Technical support group was established in the Armenian Nuclear Regulatory Authority (ANRA). The task of the group is to study modern methods of NPP in depth safety analysis for technical assistance for the ANRA, and perform independent safety assessments. ANRA will be obliged to demand assistance from various foreign organisations for preparation of different parts of the Safety Analysis Report like determination though certain parts can be prepared in Armenia

Radiochemistry and nuclear methods of analysis

International Nuclear Information System (INIS)

Ehmann, W.D.; Vance, D.

1991-01-01

This book provides both the fundamentals of radiochemistry as well as specific applications of nuclear techniques to analytical chemistry. It includes such areas of application as radioimmunoassay and activation techniques using very short-lined indicator radionuclides. It emphasizes the current nuclear methods of analysis such as neutron activation PIXE, nuclear reaction analysis, Rutherford backscattering, isotope dilution analysis and others

Application of numerical analysis techniques to eddy current testing for steam generator tubes

International Nuclear Information System (INIS)

Morimoto, Kazuo; Satake, Koji; Araki, Yasui; Morimura, Koichi; Tanaka, Michio; Shimizu, Naoya; Iwahashi, Yoichi

1994-01-01

This paper describes the application of numerical analysis to eddy current testing (ECT) for steam generator tubes. A symmetrical and three-dimensional sinusoidal steady state eddy current analysis code was developed. This code is formulated by future element method-boundary element method coupling techniques, in order not to regenerate the mesh data in the tube domain at every movement of the probe. The calculations were carried out under various conditions including those for various probe types, defect orientations and so on. Compared with the experimental data, it was shown that it is feasible to apply this code to actual use. Furthermore, we have developed a total eddy current analysis system which consists of an ECT calculation code, an automatic mesh generator for analysis, a database and display software for calculated results. ((orig.))

CURRENT STATE ANALYSIS OF AUTOMATIC BLOCK SYSTEM DEVICES, METHODS OF ITS SERVICE AND MONITORING

Directory of Open Access Journals (Sweden)

A. M. Beznarytnyy

2014-01-01

Full Text Available Purpose. Development of formalized description of automatic block system of numerical code based on the analysis of characteristic failures of automatic block system and procedure of its maintenance. Methodology. For this research a theoretical and analytical methods have been used. Findings. Typical failures of the automatic block systems were analyzed, as well as basic reasons of failure occur were found out. It was determined that majority of failures occurs due to defects of the maintenance system. Advantages and disadvantages of the current service technology of automatic block system were analyzed. Works that can be automatized by means of technical diagnostics were found out. Formal description of the numerical code of automatic block system as a graph in the state space of the system was carried out. Originality. The state graph of the numerical code of automatic block system that takes into account gradual transition from the serviceable condition to the loss of efficiency was offered. That allows selecting diagnostic information according to attributes and increasing the effectiveness of recovery operations in the case of a malfunction. Practical value. The obtained results of analysis and proposed the state graph can be used as the basis for the development of new means of diagnosing devices for automatic block system, which in turn will improve the efficiency and service of automatic block system devices in general.

Current state and development trends of inspections of steam generator tubes by eddy currents method

International Nuclear Information System (INIS)

Kubis, S.; Herman, M.

1988-01-01

The requirements are presented for steam generator tube testing and the factors are discussed affecting the accuracy of measurement by the eddy currents method. The individual types of the eddy currents method are described, such as the single-frequency method, the multi-frequency method and the pulse eddy currents method. The demands are summed up on manipulator systems whose design is adapted to the steam generator configuration conditions. (E.S.). 5 figs., 16 possu

Regression analysis of informative current status data with the additive hazards model.

Science.gov (United States)

Zhao, Shishun; Hu, Tao; Ma, Ling; Wang, Peijie; Sun, Jianguo

2015-04-01

This paper discusses regression analysis of current status failure time data arising from the additive hazards model in the presence of informative censoring. Many methods have been developed for regression analysis of current status data under various regression models if the censoring is noninformative, and also there exists a large literature on parametric analysis of informative current status data in the context of tumorgenicity experiments. In this paper, a semiparametric maximum likelihood estimation procedure is presented and in the method, the copula model is employed to describe the relationship between the failure time of interest and the censoring time. Furthermore, I-splines are used to approximate the nonparametric functions involved and the asymptotic consistency and normality of the proposed estimators are established. A simulation study is conducted and indicates that the proposed approach works well for practical situations. An illustrative example is also provided.

Cementation Analysis by Eddy Current Method

OpenAIRE

M. Zergoug; H. Oubouchou; N. Amimeur

2009-01-01

Increase the hardness, the endurance and the life time of material can be realised by surface treatments and remetallings, the electromagnetic properties of steels depend on their composition, their microstructures and constraints applied. We can use the electric and magnetic parameters to evaluate their microstructure. The object of this work is the characterization of cementation by the non-destructive methods and the determination of physicochemical parameters. Samples of low carbon tenor ...

The Analysis Methods Of 3-Monochloropropane-1,2-Diol and Glycydyl Esters in Foods, Mitigation Studies, and Current Developments About their Effects on Health

Directory of Open Access Journals (Sweden)

Aslı Yıldırım

2017-12-01

Full Text Available Chloropropanols are known as undesired food contaminants liberated during the processing of various food products. When the adverse effects of chloropropanols, especially 3-monochloropropane-1,2-diol (3-MCPD, 2-monochloropropane-1,3-diol (2-MCPD and glycidols along with their esters were first understood, the studies about the detection and mitigation of these compounds were accelerated. 3-MCPD, which was detected in food products in higher amounts when compared to other chloropropanols, usually occurs during refining process of vegetable oils, especially in deodorisation step. The novel methods in terms of the analysis of 3-MCPD and other chloropropanols are continuously updated. However, there are two basic methods today namely direct and indirect methods. Direct methods enable to detect all of the esters individually, yet, due to the necessity of a huge number of reference standards, indirect methods are currently more preferred. The first essential step of reducing chloropropanols in food products is to determine the proper analysis method. In this review, general information, new developments in analysis methods, mitigation studies and the toxigolocial data about various chloropropanols were summarized.

Motor current and leakage flux signature analysis technique for condition monitoring

International Nuclear Information System (INIS)

Pillai, M.V.; Moorthy, R.I.K.; Mahajan, S.C.

1994-01-01

Till recently analysis of vibration signals was the only means available to predict the state of health of plant equipment. Motor current and leakage magnetic flux signature analysis is acquiring importance as a technique for detection of incipient damages in the electrical machines and as a supplementary technique for diagnostics of driven equipment such as centrifugal and reciprocating pumps. The state of health of the driven equipment is assessed by analysing time signal, frequency spectrum and trend analysis. For example, the pump vane frequency, piston stroke frequency, gear frequency and bearing frequencies are indicated in the current and flux spectra. By maintaining a periodic record of the amplitudes of various frequency lines in the frequency spectra, it is possible to understand the trend of deterioration of parts and components of the pump. All problems arising out of inappropriate mechanical alignment of vertical pumps are easily identified by a combined analysis of current, flux and vibration signals. It is found that current signature analysis technique is a sufficient method in itself for the analysis of state of health of reciprocating pumps and compressors. (author). 10 refs., 4 figs

Constructing an Intelligent Patent Network Analysis Method

Directory of Open Access Journals (Sweden)

Chao-Chan Wu

2012-11-01

Full Text Available Patent network analysis, an advanced method of patent analysis, is a useful tool for technology management. This method visually displays all the relationships among the patents and enables the analysts to intuitively comprehend the overview of a set of patents in the field of the technology being studied. Although patent network analysis possesses relative advantages different from traditional methods of patent analysis, it is subject to several crucial limitations. To overcome the drawbacks of the current method, this study proposes a novel patent analysis method, called the intelligent patent network analysis method, to make a visual network with great precision. Based on artificial intelligence techniques, the proposed method provides an automated procedure for searching patent documents, extracting patent keywords, and determining the weight of each patent keyword in order to generate a sophisticated visualization of the patent network. This study proposes a detailed procedure for generating an intelligent patent network that is helpful for improving the efficiency and quality of patent analysis. Furthermore, patents in the field of Carbon Nanotube Backlight Unit (CNT-BLU were analyzed to verify the utility of the proposed method.

Machine monitoring via current signature analysis techniques

International Nuclear Information System (INIS)

Smith, S.F.; Castleberry, K.N.; Nowlin, C.H.

1992-01-01

A significant need in the effort to provide increased production quality is to provide improved plant equipment monitoring capabilities. Unfortunately, in today's tight economy, even such monitoring instrumentation must be implemented in a recognizably cost effective manner. By analyzing the electric current drawn by motors, actuator, and other line-powered industrial equipment, significant insights into the operations of the movers, driven equipment, and even the power source can be obtained. The generic term 'current signature analysis' (CSA) has been coined to describe several techniques for extracting useful equipment or process monitoring information from the electrical power feed system. A patented method developed at Oak Ridge National Laboratory is described which recognizes the presence of line-current modulation produced by motors and actuators driving varying loads. The in-situ application of applicable linear demodulation techniques to the analysis of numerous motor-driven systems is also discussed. The use of high-quality amplitude and angle-demodulation circuitry has permitted remote status monitoring of several types of medium and high-power gas compressors in (US DOE facilities) driven by 3-phase induction motors rated from 100 to 3,500 hp, both with and without intervening speed increasers. Flow characteristics of the compressors, including various forms of abnormal behavior such as surging and rotating stall, produce at the output of the specialized detectors specific time and frequency signatures which can be easily identified for monitoring, control, and fault-prevention purposes. The resultant data are similar in form to information obtained via standard vibration-sensing techniques and can be analyzed using essentially identical methods. In addition, other machinery such as refrigeration compressors, brine pumps, vacuum pumps, fans, and electric motors have been characterized

Inelastic analysis methods for piping systems

International Nuclear Information System (INIS)

Boyle, J.T.; Spence, J.

1980-01-01

The analysis of pipework systems which operate in an environment where local inelastic strains are evident is one of the most demanding problems facing the stress analyst in the nuclear field. The spatial complexity of even the most modest system makes a detailed analysis using finite element techniques beyond the scope of current computer technology. For this reason the emphasis has been on simplified methods. It is the aim of this paper to provide a reasonably complete, state-of-the-art review of inelastic pipework analysis methods and to attempt to highlight areas where reliable information is lacking and further work is needed. (orig.)

Methods for Risk Analysis

International Nuclear Information System (INIS)

Alverbro, Karin

2010-01-01

Many decision-making situations today affect humans and the environment. In practice, many such decisions are made without an overall view and prioritise one or other of the two areas. Now and then these two areas of regulation come into conflict, e.g. the best alternative as regards environmental considerations is not always the best from a human safety perspective and vice versa. This report was prepared within a major project with the aim of developing a framework in which both the environmental aspects and the human safety aspects are integrated, and decisions can be made taking both fields into consideration. The safety risks have to be analysed in order to be successfully avoided and one way of doing this is to use different kinds of risk analysis methods. There is an abundance of existing methods to choose from and new methods are constantly being developed. This report describes some of the risk analysis methods currently available for analysing safety and examines the relationships between them. The focus here is mainly on human safety aspects

A method for crack sizing using Bayesian inference arising in eddy current testing

International Nuclear Information System (INIS)

Kojima, Fumio; Kikuchi, Mitsuhiro

2008-01-01

This paper is concerned with a sizing methodology of crack using Bayesian inference arising in eddy current testing. There is often uncertainty about data through quantitative measurements of nondestructive testing and this can yield misleading inference of crack sizing at on-site monitoring. In this paper, we propose optimal strategies of measurements in eddy current testing using Bayesian prior-to-posteriori analysis. First our likelihood functional is given by Gaussian distribution with the measurement model based on the hybrid use of finite and boundary element methods. Secondly, given a priori distributions of crack sizing, we propose a method for estimating the region of interest for sizing cracks. Finally an optimal sensing method is demonstrated using our idea. (author)

Genome analysis methods - PGDBj Registered plant list, Marker list, QTL list, Plant DB link & Genome analysis methods | LSDB Archive [Life Science Database Archive metadata

Lifescience Database Archive (English)

Full Text Available List Contact us PGDBj Registered plant list, Marker list, QTL list, Plant DB link & Genome analysis methods Genome analysis... methods Data detail Data name Genome analysis methods DOI 10.18908/lsdba.nbdc01194-01-005 De...scription of data contents The current status and related information of the genomic analysis about each org...anism (March, 2014). In the case of organisms carried out genomic analysis, the d...e File name: pgdbj_dna_marker_linkage_map_genome_analysis_methods_en.zip File URL: ftp://ftp.biosciencedbc.j

UNCONTROLLED PHOTOMULTIPLIER CURRENT IN PHOTOEMISSION ANALYSIS

Directory of Open Access Journals (Sweden)

K. A. Viazava

2016-01-01

Full Text Available The dependence of photon energy from energy of photoelectron is base of photoemission radiation analysis. In such photoemission measurements except current of photocathode is always exist a reverse current from the collector of electrons to the photocathode in two-electrode sensors. There are various ways of reverse and uncontrolled current eliminating or reducing their influence. The constructive method is based on creating an electron-optical system of photoelectronic device, which would be a photoelectron energy analyzer. The second method – technological. However, it requires the manufacture of the photocathode and the dynode system in different vacuum chamber with subsequent connection to a single device in vacuum environment without exposure to the atmosphere. The purpose of this article is to determinate the effect of photoemission from photocathode chamber and the first dynode of photomultiplier on energy distribution of the photoelectrons from photocathode. To solve this problem authors obtained calibration curves for measuring pyrometer module ПИФ 4/2 with ФЭУ-114 as a sensor at supply voltage 1350 V and different decelerating voltages. The effect of illumination on the value of modulation coefficient on temperature k(T and wavelength k(λ is shown. In temperature measurements, this effect is evident in fact that at temperatures below 1400 K linear dependence ln k – T-1 is broken. Still this linear dependence is a necessary consequence of the fact that the measured temperature is color temperature. However, this calibration curve can be used to measure low temperature if the target measurements condition and calibration conditions are identical. In wavelength calibration, curve k(λ at λ > 760 nm is two-valued, that doesn’t allow to identify monochromatic radiation by this method and bring in errors in temperature measurements. 

Safety analysis - current and future regulatory challenges

Energy Technology Data Exchange (ETDEWEB)

Jamieson, T., E-mail: Terry.Jamieson@cnsc-ccsn.gc.ca [Canadian Nuclear Safety Commission, Ottawa, ON (Canada)

2015-07-01

'Full text:' The current and future regulatory challenges associated with deterministic safety analysis are reviewed, including: 1. The CNSC's and safety control areas. 2. Traditional safety analysis approach. 3. Experience gained and impact. 4. Current analysis and regulatory approaches. 5. Current status. 6. Complexity and challenges In particular, the technical, regulatory and strategic aspects of these challenges are discussed. (author)

Safety analysis - current and future regulatory challenges

International Nuclear Information System (INIS)

Jamieson, T.

2015-01-01

'Full text:' The current and future regulatory challenges associated with deterministic safety analysis are reviewed, including: 1. The CNSC's and safety control areas. 2. Traditional safety analysis approach. 3. Experience gained and impact. 4. Current analysis and regulatory approaches. 5. Current status. 6. Complexity and challenges In particular, the technical, regulatory and strategic aspects of these challenges are discussed. (author)

A Contribution To The Development And Analysis Of A Combined Current-Voltage Instrument Transformer By Using Modern CAD Methods

International Nuclear Information System (INIS)

Chundeva-Blajer, Marija M.

2004-01-01

The principle aim and task of the thesis is the analysis and development of 20 kV combined current-voltage instrument transformer (CCVIT) by using modern CAD techniques. CCVIT is a complex electromagnetic system comprising of four windings and two magnetic cores in one insulation housing for simultaneous transformation of high voltages and currents to measurable signal values by standard instruments. The analytical design methods can be applied on simple electromagnetic configurations, which is not the case with the CCVIT. There is mutual electromagnetic influence between the voltage measurement core (VMC) and the current measurement core (CMC). After the analytical CCVIT design had been done, exact determination of its metrological characteristics has been accomplished by using the numerical finite element method implemented in the FEM-3D program package. The FEM-3D calculation is made in 19 cross-sectional layers of the z-axis of the CCVIT three-dimensional domain. By FEM-3D application the three-dimensional CCVIT magnetic field distribution is derived. This is the basis for calculation of the initial metrological characteristics of the CCVIT (VMC is accuracy class 3 and CMC is accuracy class 1). By using the stochastic optimization technique based on genetic algorithm the CCVIT optimal design is achieved. The objective function is the minimum of the metrological parameters (VIM voltage error and CMC current error). There are I I independent input variables during the optimization process by which the optimal project is derived. The optimal project is adapted for realization of a prototype and the optimized project is derived. Full comparative analysis of the metrological and the electromagnetic characteristics of the three projects is accomplished. By application of the program package MATLAB/SIMULINK the CCVIT transient phenomena is analyzed for different regimes in the three design projects. In the Instrument Transformer Factory of EMO A. D.-Ohrid a CCVIT

Thermally stimulated current method applied to highly irradiated silicon diodes

CERN Document Server

Pintilie, I; Pintilie, I; Moll, Michael; Fretwurst, E; Lindström, G

2002-01-01

We propose an improved method for the analysis of Thermally Stimulated Currents (TSC) measured on highly irradiated silicon diodes. The proposed TSC formula for the evaluation of a set of TSC spectra obtained with different reverse biases leads not only to the concentration of electron and hole traps visible in the spectra but also gives an estimation for the concentration of defects which not give rise to a peak in the 30-220 K TSC temperature range (very shallow or very deep levels). The method is applied to a diode irradiated with a neutron fluence of phi sub n =1.82x10 sup 1 sup 3 n/cm sup 2.

Nodal method for fast reactor analysis

International Nuclear Information System (INIS)

Shober, R.A.

1979-01-01

In this paper, a nodal method applicable to fast reactor diffusion theory analysis has been developed. This method has been shown to be accurate and efficient in comparison to highly optimized finite difference techniques. The use of an analytic solution to the diffusion equation as a means of determining accurate coupling relationships between nodes has been shown to be highly accurate and efficient in specific two-group applications, as well as in the current multigroup method

Applying computer modeling to eddy current signal analysis for steam generator and heat exchanger tube inspections

International Nuclear Information System (INIS)

Sullivan, S.P.; Cecco, V.S.; Carter, J.R.; Spanner, M.; McElvanney, M.; Krause, T.W.; Tkaczyk, R.

2000-01-01

Licensing requirements for eddy current inspections for nuclear steam generators and heat exchangers are becoming increasingly stringent. The traditional industry-standard method of comparing inspection signals with flaw signals from simple in-line calibration standards is proving to be inadequate. A more complete understanding of eddy current and magnetic field interactions with flaws and other anomalies is required for the industry to generate consistently reliable inspections. Computer modeling is a valuable tool in improving the reliability of eddy current signal analysis. Results from computer modeling are helping inspectors to properly discriminate between real flaw signals and false calls, and improving reliability in flaw sizing. This presentation will discuss complementary eddy current computer modeling techniques such as the Finite Element Method (FEM), Volume Integral Method (VIM), Layer Approximation and other analytic methods. Each of these methods have advantages and limitations. An extension of the Layer Approximation to model eddy current probe responses to ferromagnetic materials will also be presented. Finally examples will be discussed demonstrating how some significant eddy current signal analysis problems have been resolved using appropriate electromagnetic computer modeling tools

Evaluation and presentation of analysis methods for reception analysis in reprocessing

International Nuclear Information System (INIS)

Mainka, E.

1985-01-01

The fissile material content in the dissolving or balancing tank of a reprocessing plant has special significance in nuclear fuel balancing. This is the first opportunity for destructive analysis of the fuel content of the material after burn-up of fuel elements in the reactor. In the current state-of-the-art, all balancing methods are based directly or indirectly on data obtained by chemical analysis. The following methods are evaluated: Mass-spectroscopic isotope dilution analysis, X-ray fluorescence spectroscopy, Isotopic correlation, Gamma absorptiometry, Redox titration, Emission spectroscopy after plasma excitation, Alpha spectroscopy, and Laser Raman spectroscopy

Gas stream analysis using voltage-current time differential operation of electrochemical sensors

Science.gov (United States)

Woo, Leta Yar-Li; Glass, Robert Scott; Fitzpatrick, Joseph Jay; Wang, Gangqiang; Henderson, Brett Tamatea; Lourdhusamy, Anthoniraj; Steppan, James John; Allmendinger, Klaus Karl

2018-01-02

A method for analysis of a gas stream. The method includes identifying an affected region of an affected waveform signal corresponding to at least one characteristic of the gas stream. The method also includes calculating a voltage-current time differential between the affected region of the affected waveform signal and a corresponding region of an original waveform signal. The affected region and the corresponding region of the waveform signals have a sensitivity specific to the at least one characteristic of the gas stream. The method also includes generating a value for the at least one characteristic of the gas stream based on the calculated voltage-current time differential.

Novel approach in quantitative analysis of shearography method

International Nuclear Information System (INIS)

Wan Saffiey Wan Abdullah

2002-01-01

The application of laser interferometry in industrial non-destructive testing and material characterization is becoming more prevalent since this method provides non-contact full-field inspection of the test object. However their application only limited to the qualitative analysis, current trend has changed to the development of this method by the introduction of quantitative analysis, which attempts to detail the defect examined. This being the design feature for a ranges of object size to be examined. The growing commercial demand for quantitative analysis for NDT and material characterization is determining the quality of optical and analysis instrument. However very little attention is currently being paid to understanding, quantifying and compensating for the numerous error sources which are a function of interferometers. This paper presents a comparison of measurement analysis using the established theoretical approach and the new approach, taken into account the factor of divergence illumination and other geometrical factors. The difference in the measurement system could be associated in the error factor. (Author)

Magnetic force microscopy method and apparatus to detect and image currents in integrated circuits

Science.gov (United States)

Campbell, Ann. N.; Anderson, Richard E.; Cole, Jr., Edward I.

1995-01-01

A magnetic force microscopy method and improved magnetic tip for detecting and quantifying internal magnetic fields resulting from current of integrated circuits. Detection of the current is used for failure analysis, design verification, and model validation. The interaction of the current on the integrated chip with a magnetic field can be detected using a cantilevered magnetic tip. Enhanced sensitivity for both ac and dc current and voltage detection is achieved with voltage by an ac coupling or a heterodyne technique. The techniques can be used to extract information from analog circuits.

Permanent Magnet Eddy Current Loss Analysis of a Novel Motor Integrated Permanent Magnet Gear

DEFF Research Database (Denmark)

Zhang, Yuqiu; Lu, Kaiyuan; Ye, Yunyue

2012-01-01

In this paper, a new motor integrated permanent magnet gear (MIPMG) is discussed. The focus is on eddy current loss analysis associated to permanent magnets (PMs). A convenient model of MIPMG is provided based on 2-D field-motion coupled time-stepping finite element method for transient eddy...... current analysis. The model takes the eddy current effect of PMs into account in determination of the magnetic field in the air-gap and in the magnet regions. The eddy current losses generated in the magnets are properly interpreted. Design improvements for reducing the eddy current losses are suggested...

Method for statistical data analysis of multivariate observations

CERN Document Server

Gnanadesikan, R

1997-01-01

A practical guide for multivariate statistical techniques-- now updated and revised In recent years, innovations in computer technology and statistical methodologies have dramatically altered the landscape of multivariate data analysis. This new edition of Methods for Statistical Data Analysis of Multivariate Observations explores current multivariate concepts and techniques while retaining the same practical focus of its predecessor. It integrates methods and data-based interpretations relevant to multivariate analysis in a way that addresses real-world problems arising in many areas of inte

Silicon radiation detector analysis using back electron beam induced current

International Nuclear Information System (INIS)

Guye, R.

1987-01-01

A new technique for the observation and analysis of defects in silicon radiation detectors is described. This method uses an electron beam from a scanning electron microscope (SEM) impinging on the rear side of the p + n junction of the silicon detector, which itself is active and detects the electron beam induced current (EBIC). It is shown that this current is a sensitive probe of localized trapping centers, either at the junction surface or somewhere in the volume of the silicon crystal. (orig.)

Transit Traffic Analysis Zone Delineating Method Based on Thiessen Polygon

Directory of Open Access Journals (Sweden)

Shuwei Wang

2014-04-01

Full Text Available A green transportation system composed of transit, busses and bicycles could be a significant in alleviating traffic congestion. However, the inaccuracy of current transit ridership forecasting methods is imposing a negative impact on the development of urban transit systems. Traffic Analysis Zone (TAZ delineating is a fundamental and essential step in ridership forecasting, existing delineating method in four-step models have some problems in reflecting the travel characteristics of urban transit. This paper aims to come up with a Transit Traffic Analysis Zone delineation method as supplement of traditional TAZs in transit service analysis. The deficiencies of current TAZ delineating methods were analyzed, and the requirements of Transit Traffic Analysis Zone (TTAZ were summarized. Considering these requirements, Thiessen Polygon was introduced into TTAZ delineating. In order to validate its feasibility, Beijing was then taken as an example to delineate TTAZs, followed by a spatial analysis of office buildings within a TTAZ and transit station departure passengers. Analysis result shows that the TTAZs based on Thiessen polygon could reflect the transit travel characteristic and is of in-depth research value.

Insulator Contamination Forecasting Based on Fractal Analysis of Leakage Current

Directory of Open Access Journals (Sweden)

Bing Luo

2012-07-01

Full Text Available In this paper, an artificial pollution test is carried out to study the leakage current of porcelain insulators. Fractal theory is adopted to extract the characteristics hidden in leakage current waveforms. Fractal dimensions of the leakage current for the security, forecast and danger zones are analyzed under four types of degrees of contamination. The mean value and the standard deviation of the fractal dimension in the forecast zone are calculated to characterize the differences. The analysis reveals large differences in the fractal dimension of leakage current under different contamination discharge stages and degrees. The experimental and calculation results suggest that the fractal dimension of a leakage current waveform can be used as a new indicator of the discharge process and contamination degree of insulators. The results provide new methods and valid indicators for forecasting contamination flashovers.

Current measurement method for characterization of fast switching power semiconductors with Silicon Steel Current Transformer

DEFF Research Database (Denmark)

Li, Helong; Beczkowski, Szymon; Munk-Nielsen, Stig

2015-01-01

This paper proposes a novel current measurement method with Silicon Steel Current Transformer (SSCT) for the characterization of fast switching power semiconductors. First, the existing current sensors for characterization of fast switching power semiconductors are experimentally evaluated...

Safety relief valve alternate analysis method

International Nuclear Information System (INIS)

Adams, R.H.; Javid, A.; Khatua, T.P.

1981-01-01

An experimental test program was started in the United States in 1976 to define and quantify Safety Relief Valve (SRV) phenomena in General Electric Mark I Suppression Chambers. The testing considered several discharged devices and was used to correlate SRV load prediction models. The program was funded by utilities with Mark I containments and has resulted in a detailed SRV load definition as a portion of the Mark I containment program Load Definition Report (LDR). The (USNRC) has reviewed and approved the LDR SRV load definition. In addition, the USNRC has permitted calibration of structural models used for predicting torus response to SRV loads. Model calibration is subject to confirmatory in-plant testing. The SRV methodology given in the LDR requires that transient dynamic pressures be applied to a torus structural model that includes a fluid added mass matrix. Preliminary evaluations of torus response have indicated order of magnitude conservatisms, with respect to test results, which could result in unrealistic containment modifications. In addition, structural response trends observed in full-scale tests between cold pipe, first valve actuation and hot pipe, subsequent valve actuation conditions have not been duplicated using current analysis methods. It was suggested by others that an energy approach using current fluid models be utilized to define loads. An alternate SRV analysis method is defined to correct suppression chamber structural response to a level that permits economical but conservative design. Simple analogs are developed for the purpose of correcting the analytical response obtained from LDR analysis methods. Analogs evaluated considered forced vibration and free vibration structural response. The corrected response correlated well with in-plant test response. The correlation of the analytical model at test conditions permits application of the alternate analysis method at design conditions. (orig./HP)

Current exposure method for CCP’s under Basel III

Directory of Open Access Journals (Sweden)

Antonie Kotzé

2013-04-01

Full Text Available Exposure-at-default is one of the most interesting and most difficult parameters to estimate in counterparty credit risk. Basel I offered only the non-internal Current Exposure Method for estimating this quantity whilst Basel II further introduced the Standardized Method and an Internal Model Method. Under new Basel III rules a central counterparty is defined as being a financial institution. New principles set out by the Basel Committee on Banking Supervision forces Central Counterparties in using the Current Exposure Method when estimating the credit exposures to Clearing Member banks notwithstanding its shortcomings. The Current Exposure Method relies on the Value-at-Risk methodology and its characteristics are discussed in this note. We will particularly investigate exposures to SAFCOM, the South African clearing house and point to a mathematical discrepancy on how netting is effected through the Basel accord.

Application of spectral analysis for differentiation between metals using signals from eddy-current transducers

OpenAIRE

Abramovych, Anton; Poddubny, Volodymyr

2017-01-01

The authors theoretically and experimentally substantiated the use of the spectral method for processing a signal of the vortex-current metal detector for dichotomous differentiation between metals. Results of experimental research that prove the possibility of using spectral analysis for differentiation between metals were presented. The vortex-current method for detection of hidden metal objects was analyzed. It was indicated that amplitude of output VCD signal is determined by electric con...

Assessing thermochromatography as a separation method for nuclear forensics. Current capability vis-a-vis forensic requirements

International Nuclear Information System (INIS)

Hanson, D.E.; Garrison, J.R.; Hall, H.L.

2011-01-01

Nuclear forensic science has become increasingly important for global nuclear security. However, many current laboratory analysis techniques are based on methods developed without the imperative for timely analysis that underlies the post-detonation forensics mission requirements. Current analysis of actinides, fission products, and fuel-specific materials requires time-consuming chemical separation coupled with nuclear counting or mass spectrometry. High-temperature gas-phase separations have been used in the past for the rapid separation of newly created elements/isotopes and as a basis for chemical classification of that element. We are assessing the utility of this method for rapid separation in the gas-phase to accelerate the separations of radioisotopes germane to post-detonation nuclear forensic investigations. The existing state of the art for thermo chromatographic separations, and its applicability to nuclear forensics, will be reviewed. (author)

Calculation of an axisymmetric current coil field with the bounding contour integration method

Energy Technology Data Exchange (ETDEWEB)

Telegin, Alexander P.; Klevets, Nickolay I. E-mail: pmsolution@mail.ru

2004-06-01

Method for the economic and stable (in the sense of calculation errors) analysis of an induction of a magnetic field created with axisymmetric coils in arbitrary points of space, including points located inside a coil or on its border, is obtained. The basic idea of the method is to replace a current coil with continuous distribution of current density by magnetization distributed in the volume of the coil and creating the equivalent magnetic field. This allows to use field surface sources at calculation of the fields. Consequently, the range of integration is reduced resulting in reduction of calculation volume by an order in most cases. Besides, the calculation of improper integrals in internal points and on the border is completely excluded.

Calculation of an axisymmetric current coil field with the bounding contour integration method

International Nuclear Information System (INIS)

Telegin, Alexander P.; Klevets, Nickolay I.

2004-01-01

Method for the economic and stable (in the sense of calculation errors) analysis of an induction of a magnetic field created with axisymmetric coils in arbitrary points of space, including points located inside a coil or on its border, is obtained. The basic idea of the method is to replace a current coil with continuous distribution of current density by magnetization distributed in the volume of the coil and creating the equivalent magnetic field. This allows to use field surface sources at calculation of the fields. Consequently, the range of integration is reduced resulting in reduction of calculation volume by an order in most cases. Besides, the calculation of improper integrals in internal points and on the border is completely excluded

Comparison of a Label-Free Quantitative Proteomic Method Based on Peptide Ion Current Area to the Isotope Coded Affinity Tag Method

Directory of Open Access Journals (Sweden)

Young Ah Goo

2008-01-01

Full Text Available Recently, several research groups have published methods for the determination of proteomic expression profiling by mass spectrometry without the use of exogenously added stable isotopes or stable isotope dilution theory. These so-called label-free, methods have the advantage of allowing data on each sample to be acquired independently from all other samples to which they can later be compared in silico for the purpose of measuring changes in protein expression between various biological states. We developed label free software based on direct measurement of peptide ion current area (PICA and compared it to two other methods, a simpler label free method known as spectral counting and the isotope coded affinity tag (ICAT method. Data analysis by these methods of a standard mixture containing proteins of known, but varying, concentrations showed that they performed similarly with a mean squared error of 0.09. Additionally, complex bacterial protein mixtures spiked with known concentrations of standard proteins were analyzed using the PICA label-free method. These results indicated that the PICA method detected all levels of standard spiked proteins at the 90% confidence level in this complex biological sample. This finding confirms that label-free methods, based on direct measurement of the area under a single ion current trace, performed as well as the standard ICAT method. Given the fact that the label-free methods provide ease in experimental design well beyond pair-wise comparison, label-free methods such as our PICA method are well suited for proteomic expression profiling of large numbers of samples as is needed in clinical analysis.

Study on UPF Harmonic Current Detection Method Based on DSP

Energy Technology Data Exchange (ETDEWEB)

Zhao, H J [Northwestern Polytechnical University, Xi' an 710072 (China); Pang, Y F [Xi' an University of Technology, Xi' an 710048 (China); Qiu, Z M [Xi' an University of Technology, Xi' an 710048 (China); Chen, M [Northwestern Polytechnical University, Xi' an 710072 (China)

2006-10-15

Unity power factor (UPF) harmonic current detection method applied to active power filter (APF) is presented in this paper. The intention of this method is to make nonlinear loads and active power filter in parallel to be an equivalent resistance. So after compensation, source current is sinusoidal, and has the same shape of source voltage. Meanwhile, there is no harmonic in source current, and the power factor becomes one. The mathematic model of proposed method and the optimum project for equivalent low pass filter in measurement are presented. Finally, the proposed detection method applied to a shunt active power filter experimental prototype based on DSP TMS320F2812 is developed. Simulation and experiment results indicate the method is simple and easy to implement, and can obtain the real-time calculation of harmonic current exactly.

Elastic and inelastic methods of piping systems analysis: a preliminary review

International Nuclear Information System (INIS)

Reich, M.; Esztergar, E.P.; Spence, J.; Boyle, J.; Chang, T.Y.

1975-02-01

A preliminary review of the methods used for elastic and inelastic piping system analysis is presented. The following principal conclusions are reached: techniques for the analysis of complex piping systems operating in the high temperature creep regime should be further developed; accurate analysis of a complete pipework system in creep using the ''complete shell finite element methods'' is not feasible at the present, and the ''reduced shell finite element method'' still requires excessive computer time and also requires further investigation regarding the compatibility problems associated with the pipe bend element, particularly when applied to cases involving general loading conditions; and with the current size of proposed high temperature systems requiring the evaluation of long-term operating life (30 to 40 years), it is important to adopt a simplified analysis method. A design procedure for a simplified analysis method based on currently available techniques applied in a three-stage approach is outlined. The work required for implementation of these procedures together with desirable future developments are also briefly discussed. Other proposed simplified approximations also are reviewed in the text. 101 references. (U.S.)

Analysis of tidal currents in the North Sea from shipboard acoustic Doppler current profiler data

Science.gov (United States)

Vindenes, Håvard; Orvik, Kjell Arild; Søiland, Henrik; Wehde, Henning

2018-06-01

North Sea tidal currents are determined by applying harmonic analysis to ship-borne acoustic Doppler current profiler data recorded from 1999 to 2016, covering large areas of the northern North Sea. Direct current measurement data sets of this magnitude are rare in the otherwise well investigated North Sea, and thus it is a valuable asset in studying and expanding our understanding of its tidal currents and circulation in general. The harmonic analysis is applied to a least squares fit of the current observations at a set of knot points. Results from the harmonic analysis compare favorably to tidal parameters estimated from observations from moored instruments. The analysis shows that the tides are characterized by strong semi-diurnal component, with amplitudes of the principal Lunar constituent ranging from 1.6 cm/s in the Skagerrak to 67 cm/s in the Fair Isle Channel. Diurnal tides are found to be approximately one fifth the strength of the predominant semi-diurnal constituent. Output from a regional barotropic tide model compares well to tidal current determined from the harmonic analysis of the Acoustic Doppler Current Profiler data.

Current studies of biological materials using instrumental and radiochemical neutron activation analysis

International Nuclear Information System (INIS)

Fardy, J.J.; McOrist, G.D.; Farrar, Y.J.

1985-01-01

Instrumental neutron activation analysis still remains the preferred option when analysing the trace element distribution in a wide rage of materials by neutron activation analysis. However, when lower limits of detection are required or major interferences reduce the effectiveness of this technique, radiochemical neutron activation analysis is applied. This paper examines the current use of both methods and the development of rapid radiochemical techniques for analysis of the biological materials, hair, cow's milk, human's milk, milk powder, blood and blood serum

Analysis and Modeling of Circulating Current in Two Parallel-Connected Inverters

DEFF Research Database (Denmark)

Maheshwari, Ram Krishan; Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand

2015-01-01

Parallel-connected inverters are gaining attention for high power applications because of the limited power handling capability of the power modules. Moreover, the parallel-connected inverters may have low total harmonic distortion of the ac current if they are operated with the interleaved pulse...... this model, the circulating current between two parallel-connected inverters is analysed in this study. The peak and root mean square (rms) values of the normalised circulating current are calculated for different PWM methods, which makes this analysis a valuable tool to design a filter for the circulating......-width modulation (PWM). However, the interleaved PWM causes a circulating current between the inverters, which in turn causes additional losses. A model describing the dynamics of the circulating current is presented in this study which shows that the circulating current depends on the common-mode voltage. Using...

On-line Monitoring Device for High-voltage Switch Cabinet Partial Discharge Based on Pulse Current Method

Science.gov (United States)

Y Tao, S.; Zhang, X. Z.; Cai, H. W.; Li, P.; Feng, Y.; Zhang, T. C.; Li, J.; Wang, W. S.; Zhang, X. K.

2017-12-01

The pulse current method for partial discharge detection is generally applied in type testing and other off-line tests of electrical equipment at delivery. After intensive analysis of the present situation and existing problems of partial discharge detection in switch cabinets, this paper designed the circuit principle and signal extraction method for partial discharge on-line detection based on a high-voltage presence indicating systems (VPIS), established a high voltage switch cabinet partial discharge on-line detection circuit based on the pulse current method, developed background software integrated with real-time monitoring, judging and analyzing functions, carried out a real discharge simulation test on a real-type partial discharge defect simulation platform of a 10KV switch cabinet, and verified the sensitivity and validity of the high-voltage switch cabinet partial discharge on-line monitoring device based on the pulse current method. The study presented in this paper is of great significance for switch cabinet maintenance and theoretical study on pulse current method on-line detection, and has provided a good implementation method for partial discharge on-line monitoring devices for 10KV distribution network equipment.

PROOF OF CONCEPT FOR A HUMAN RELIABILITY ANALYSIS METHOD FOR HEURISTIC USABILITY EVALUATION OF SOFTWARE

International Nuclear Information System (INIS)

Ronald L. Boring; David I. Gertman; Jeffrey C. Joe; Julie L. Marble

2005-01-01

An ongoing issue within human-computer interaction (HCI) is the need for simplified or ''discount'' methods. The current economic slowdown has necessitated innovative methods that are results driven and cost effective. The myriad methods of design and usability are currently being cost-justified, and new techniques are actively being explored that meet current budgets and needs. Recent efforts in human reliability analysis (HRA) are highlighted by the ten-year development of the Standardized Plant Analysis Risk HRA (SPAR-H) method. The SPAR-H method has been used primarily for determining human centered risk at nuclear power plants. The SPAR-H method, however, shares task analysis underpinnings with HCI. Despite this methodological overlap, there is currently no HRA approach deployed in heuristic usability evaluation. This paper presents an extension of the existing SPAR-H method to be used as part of heuristic usability evaluation in HCI

Method and apparatus for current-output peak detection

Science.gov (United States)

De Geronimo, Gianluigi

2017-01-24

A method and apparatus for a current-output peak detector. A current-output peak detector circuit is disclosed and works in two phases. The peak detector circuit includes switches to switch the peak detector circuit from the first phase to the second phase upon detection of the peak voltage of an input voltage signal. The peak detector generates a current output with a high degree of accuracy in the second phase.

Trends in Mediation Analysis in Nursing Research: Improving Current Practice.

Science.gov (United States)

Hertzog, Melody

2018-06-01

The purpose of this study was to describe common approaches used by nursing researchers to test mediation models and evaluate them within the context of current methodological advances. MEDLINE was used to locate studies testing a mediation model and published from 2004 to 2015 in nursing journals. Design (experimental/correlation, cross-sectional/longitudinal, model complexity) and analysis (method, inclusion of test of mediated effect, violations/discussion of assumptions, sample size/power) characteristics were coded for 456 studies. General trends were identified using descriptive statistics. Consistent with findings of reviews in other disciplines, evidence was found that nursing researchers may not be aware of the strong assumptions and serious limitations of their analyses. Suggestions for strengthening the rigor of such studies and an overview of current methods for testing more complex models, including longitudinal mediation processes, are presented.

The current matrix elements from HAL QCD method

Science.gov (United States)

Watanabe, Kai; Ishii, Noriyoshi

2018-03-01

HAL QCD method is a method to construct a potential (HAL QCD potential) that reproduces the NN scattering phase shift faithful to the QCD. The HAL QCD potential is obtained from QCD by eliminating the degrees of freedom of quarks and gluons and leaving only two particular hadrons. Therefor, in the effective quantum mechanics of two nucleons defined by HAL QCD potential, the conserved current consists not only of the nucleon current but also an extra current originating from the potential (two-body current). Though the form of the two-body current is closely related to the potential, it is not straight forward to extract the former from the latter. In this work, we derive the the current matrix element formula in the quantum mechanics defined by the HAL QCD potential. As a first step, we focus on the non-relativistic case. To give an explicit example, we consider a second quantized non-relativistic two-channel coupling model which we refer to as the original model. From the original model, the HAL QCD potential for the open channel is constructed by eliminating the closed channel in the elastic two-particle scattering region. The current matrix element formula is derived by demanding the effective quantum mechanics defined by the HAL QCD potential to respond to the external field in the same way as the original two-channel coupling model.

Statistical learning methods in high-energy and astrophysics analysis

Energy Technology Data Exchange (ETDEWEB)

Zimmermann, J. [Forschungszentrum Juelich GmbH, Zentrallabor fuer Elektronik, 52425 Juelich (Germany) and Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Munich (Germany)]. E-mail: zimmerm@mppmu.mpg.de; Kiesling, C. [Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Munich (Germany)

2004-11-21

We discuss several popular statistical learning methods used in high-energy- and astro-physics analysis. After a short motivation for statistical learning we present the most popular algorithms and discuss several examples from current research in particle- and astro-physics. The statistical learning methods are compared with each other and with standard methods for the respective application.

Statistical learning methods in high-energy and astrophysics analysis

International Nuclear Information System (INIS)

Zimmermann, J.; Kiesling, C.

2004-01-01

We discuss several popular statistical learning methods used in high-energy- and astro-physics analysis. After a short motivation for statistical learning we present the most popular algorithms and discuss several examples from current research in particle- and astro-physics. The statistical learning methods are compared with each other and with standard methods for the respective application

CMS Data Analysis: Current Status and Future Strategy

CERN Document Server

Innocente, V

2003-01-01

We present the current status of CMS data analysis architecture and describe work on future Grid-based distributed analysis prototypes. CMS has two main software frameworks related to data analysis: COBRA, the main framework, and IGUANA, the interactive visualisation framework. Software using these frameworks is used today in the world-wide production and analysis of CMS data. We describe their overall design and present examples of their current use with emphasis on interactive analysis. CMS is currently developing remote analysis prototypes, including one based on Clarens, a Grid-enabled client-server tool. Use of the prototypes by CMS physicists will guide us in forming a Grid-enriched analysis strategy. The status of this work is presented, as is an outline of how we plan to leverage the power of our existing frameworks in the migration of CMS software to the Grid.

Eddy current analysis in fusion devices

International Nuclear Information System (INIS)

Turner, L.R.

1988-06-01

In magnetic fusion devices, particularly tokamaks and reversed field pinch (RFP) experiments, time-varying magnetic fields are in intimate contact with electrically conducting components of the device. Induced currents, fields, forces, and torques result. This note reviews the analysis of eddy current effects in the following systems: Interaction of a tokamak plasma with the eddy currents in the first wall, blanket, and shield (FWBS) systems; Eddy currents in a complex but two-dimensional vacuum vessel, as in TFTR, JET, and JT-60; Eddy currents in the FWBS system of a tokamak reactor, such as NET, FER, or ITER; and Eddy currents in a RFP shell. The cited studies are chosen to be illustrative, rather than exhaustive. 42 refs

Electrostatic Discharge Current Linear Approach and Circuit Design Method

Directory of Open Access Journals (Sweden)

Pavlos K. Katsivelis

2010-11-01

Full Text Available The Electrostatic Discharge phenomenon is a great threat to all electronic devices and ICs. An electric charge passing rapidly from a charged body to another can seriously harm the last one. However, there is a lack in a linear mathematical approach which will make it possible to design a circuit capable of producing such a sophisticated current waveform. The commonly accepted Electrostatic Discharge current waveform is the one set by the IEC 61000-4-2. However, the over-simplified circuit included in the same standard is incapable of producing such a waveform. Treating the Electrostatic Discharge current waveform of the IEC 61000-4-2 as reference, an approximation method, based on Prony’s method, is developed and applied in order to obtain a linear system’s response. Considering a known input, a method to design a circuit, able to generate this ESD current waveform in presented. The circuit synthesis assumes ideal active elements. A simulation is carried out using the PSpice software.

Rotor current transient analysis of DFIG-based wind turbines during symmetrical voltage faults

International Nuclear Information System (INIS)

Ling, Yu; Cai, Xu; Wang, Ningbo

2013-01-01

Highlights: • We theoretically analyze the rotor fault current of DFIG based on space vector. • The presented analysis is simple, easy to understand. • The analysis highlights the accuracy of the expression of the rotor fault currents. • The expression can be widely used to analyze the different levels of voltage symmetrical fault. • Simulation results show the accuracy of the expression of the rotor currents. - Abstract: The impact of grid voltage fault on doubly fed induction generators (DFIGs), especially rotor currents, has received much attention. So, in this paper, the rotor currents of based-DFIG wind turbines are considered in a generalized way, which can be widely used to analyze the cases under different levels of voltage symmetrical faults. A direct method based on space vector is proposed to obtain an accurate expression of rotor currents as a function of time for symmetrical voltage faults in the power system. The presented theoretical analysis is simple and easy to understand and especially highlights the accuracy of the expression. Finally, the comparable simulations evaluate this analysis and show that the expression of the rotor currents is sufficient to calculate the maximum fault current, DC and AC components, and especially helps to understand the causes of the problem and as a result, contributes to adapt reasonable approaches to enhance the fault ride through (FRT) capability of DFIG wind turbines during a voltage fault

Scalable Kernel Methods and Algorithms for General Sequence Analysis

Science.gov (United States)

Kuksa, Pavel

2011-01-01

Analysis of large-scale sequential data has become an important task in machine learning and pattern recognition, inspired in part by numerous scientific and technological applications such as the document and text classification or the analysis of biological sequences. However, current computational methods for sequence comparison still lack…

Method for measuring the resistive transition and critical current in superconductors using pulsed current

International Nuclear Information System (INIS)

McGinnis, W.C.; Jones, T.E.

1993-01-01

A method is described for measuring the intragranular critical current of a granular superconductive material, comprising the steps of: conducting a substantially rectangular electronic pulse through said material so as to conduct a current through said material such that when said intragranular critical current of said material is exceeded, any grains present in said material are in a superconducting state when said current is less than said intragranular critical current, said material having a critical temperature; measuring said current through said material while conducting said pulse; measuring a voltage difference across said material while conducting said pulse; and determining said intragranular critical current through said material by varying said current to discern a current level at which an electrical resistance of said material increases to that of a non-superconducting state as the grains of said material transition from said superconducting to said non-superconducting state

Decentralised control method for DC microgrids with improved current sharing accuracy

DEFF Research Database (Denmark)

Yang, Jie; Jin, Xinmin; Wu, Xuezhi

2017-01-01

A decentralised control method that deals with current sharing issues in dc microgrids (MGs) is proposed in this study. The proposed method is formulated in terms of ‘modified global indicator’ concept, which was originally proposed to improve reactive power sharing in ac MGs. In this work......, the ‘modified global indicator’ concept is extended to coordinate dc MGs, which aims to preserve the main features offered by decentralised control methods such as no need of communication links, central controller or knowledge of the microgrid topology and parameters. This global indicator is inserted between...... a shunt virtual resistance. The operation under multiple dc-buses is also included in order to enhance the applicability of the proposed controller. A detailed mathematical model including the effect of network mismatches is derived for analysis of the stability of the proposed controller. The feasibility...

Current Applications of Chromatographic Methods in the Study of Human Body Fluids for Diagnosing Disorders.

Science.gov (United States)

Jóźwik, Jagoda; Kałużna-Czaplińska, Joanna

2016-01-01

Currently, analysis of various human body fluids is one of the most essential and promising approaches to enable the discovery of biomarkers or pathophysiological mechanisms for disorders and diseases. Analysis of these fluids is challenging due to their complex composition and unique characteristics. Development of new analytical methods in this field has made it possible to analyze body fluids with higher selectivity, sensitivity, and precision. The composition and concentration of analytes in body fluids are most often determined by chromatography-based techniques. There is no doubt that proper use of knowledge that comes from a better understanding of the role of body fluids requires the cooperation of scientists of diverse specializations, including analytical chemists, biologists, and physicians. This article summarizes current knowledge about the application of different chromatographic methods in analyses of a wide range of compounds in human body fluids in order to diagnose certain diseases and disorders.

Computational methods in calculating superconducting current problems

Science.gov (United States)

Brown, David John, II

Various computational problems in treating superconducting currents are examined. First, field inversion in spatial Fourier transform space is reviewed to obtain both one-dimensional transport currents flowing down a long thin tape, and a localized two-dimensional current. The problems associated with spatial high-frequency noise, created by finite resolution and experimental equipment, are presented, and resolved with a smooth Gaussian cutoff in spatial frequency space. Convergence of the Green's functions for the one-dimensional transport current densities is discussed, and particular attention is devoted to the negative effects of performing discrete Fourier transforms alone on fields asymptotically dropping like 1/r. Results of imaging simulated current densities are favorably compared to the original distributions after the resulting magnetic fields undergo the imaging procedure. The behavior of high-frequency spatial noise, and the behavior of the fields with a 1/r asymptote in the imaging procedure in our simulations is analyzed, and compared to the treatment of these phenomena in the published literature. Next, we examine calculation of Mathieu and spheroidal wave functions, solutions to the wave equation in elliptical cylindrical and oblate and prolate spheroidal coordinates, respectively. These functions are also solutions to Schrodinger's equations with certain potential wells, and are useful in solving time-varying superconducting problems. The Mathieu functions are Fourier expanded, and the spheroidal functions expanded in associated Legendre polynomials to convert the defining differential equations to recursion relations. The infinite number of linear recursion equations is converted to an infinite matrix, multiplied by a vector of expansion coefficients, thus becoming an eigenvalue problem. The eigenvalue problem is solved with root solvers, and the eigenvector problem is solved using a Jacobi-type iteration method, after preconditioning the

Findings from analysing and quantifying human error using current methods

International Nuclear Information System (INIS)

Dang, V.N.; Reer, B.

1999-01-01

In human reliability analysis (HRA), the scarcity of data means that, at best, judgement must be applied to transfer to the domain of the analysis what data are available for similar tasks. In particular for the quantification of tasks involving decisions, the analyst has to choose among quantification approaches that all depend to a significant degree on expert judgement. The use of expert judgement can be made more reliable by eliciting relative judgements rather than absolute judgements. These approaches, which are based on multiple criterion decision theory, focus on ranking the tasks to be analysed by difficulty. While these approaches remedy at least partially the poor performance of experts in the estimation of probabilities, they nevertheless require the calibration of the relative scale on which the actions are ranked in order to obtain the probabilities of interest. This paper presents some results from a comparison of some current HRA methods performed in the frame of a study of SLIM calibration options. The HRA quantification methods THERP, HEART, and INTENT were applied to derive calibration human error probabilities for two groups of operator actions. (author)

Fluxball magnetic field analysis using a hybrid analytical/FEM/BEM with equivalent currents

International Nuclear Information System (INIS)

Fernandes, João F.P.; Camilo, Fernando M.; Machado, V. Maló

2016-01-01

In this paper, a fluxball electric machine is analyzed concerning the magnetic flux, force and torque. A novel method is proposed based in a special hybrid FEM/BEM (Finite Element Method/Boundary Element Method) with equivalent currents by using an analytical treatment for the source field determination. The method can be applied to evaluate the magnetic field in axisymmetric problems, in the presence of several magnetic materials. Same results obtained by a commercial Finite Element Analysis tool are presented for validation purposes with the proposed method. - Highlights: • The Fluxball machine magnetic field is analyzed by a new FEM/BEM/Analytical method. • The method is adequate for axisymmetric non homogeneous magnetic field problems. • The source magnetic field is evaluated considering a non-magnetic equivalent problem. • Material magnetization vectors are accounted by using equivalent currents. • A strong reduction of the finite element domain is achieved.

Analysis of Statistical Methods Currently used in Toxicology Journals.

Science.gov (United States)

Na, Jihye; Yang, Hyeri; Bae, SeungJin; Lim, Kyung-Min

2014-09-01

Statistical methods are frequently used in toxicology, yet it is not clear whether the methods employed by the studies are used consistently and conducted based on sound statistical grounds. The purpose of this paper is to describe statistical methods used in top toxicology journals. More specifically, we sampled 30 papers published in 2014 from Toxicology and Applied Pharmacology, Archives of Toxicology, and Toxicological Science and described methodologies used to provide descriptive and inferential statistics. One hundred thirteen endpoints were observed in those 30 papers, and most studies had sample size less than 10, with the median and the mode being 6 and 3 & 6, respectively. Mean (105/113, 93%) was dominantly used to measure central tendency, and standard error of the mean (64/113, 57%) and standard deviation (39/113, 34%) were used to measure dispersion, while few studies provide justifications regarding why the methods being selected. Inferential statistics were frequently conducted (93/113, 82%), with one-way ANOVA being most popular (52/93, 56%), yet few studies conducted either normality or equal variance test. These results suggest that more consistent and appropriate use of statistical method is necessary which may enhance the role of toxicology in public health.

Sub-bandgap photonic base current method for characterization of interface states at heterointerfaces in heterojunction bipolar transistors

International Nuclear Information System (INIS)

Shin, H. T.; Kim, K. H.; Kim, K. S.

2004-01-01

In this paper, we propose a novel photonic base current analysis method to characterize the interface states in heterojunction bipolar transistors (HBTs) by using the photonic I-V characteristics under sub-bandgap photonic excitation. For the photonic current-voltage characterization of HBTs, an optical source with a photon energy less than the bandgap energy of Al 0.3 Ga 0.7 As and GaAs (E ph = 0.95 eV g,AlGaAs = 1.79 eV, E g,GaAs = 1.45 eV) is employed for the characterization of the interface states distributed in the photo-responsive energy band (E C - 0.95 ≤ E it ≤ E C ) in emitter-base heterojunction at HBTs. The proposed novel method, which is applied to bipolar junction transistors for the first time, is simple, and an accurate analysis of interface traps in HBTs is possible. By using the photonic base-current and the dark-base-current, we qualitatively analyze the interface trap at the Al 0.3 Ga 0.7 As/GaAs heterojunction interface in HBTs.

Current Directions in Mediation Analysis

Science.gov (United States)

MacKinnon, David P.; Fairchild, Amanda J.

2010-01-01

Mediating variables continue to play an important role in psychological theory and research. A mediating variable transmits the effect of an antecedent variable on to a dependent variable, thereby providing more detailed understanding of relations among variables. Methods to assess mediation have been an active area of research for the last two decades. This paper describes the current state of methods to investigate mediating variables. PMID:20157637

Current Directions in Mediation Analysis

OpenAIRE

MacKinnon, David P.; Fairchild, Amanda J.

2009-01-01

Mediating variables continue to play an important role in psychological theory and research. A mediating variable transmits the effect of an antecedent variable on to a dependent variable, thereby providing more detailed understanding of relations among variables. Methods to assess mediation have been an active area of research for the last two decades. This paper describes the current state of methods to investigate mediating variables.

Assessment of current state of the art in modeling techniques and analysis methods for large space structures

Science.gov (United States)

Noor, A. K.

1983-01-01

Advances in continuum modeling, progress in reduction methods, and analysis and modeling needs for large space structures are covered with specific attention given to repetitive lattice trusses. As far as continuum modeling is concerned, an effective and verified analysis capability exists for linear thermoelastic stress, birfurcation buckling, and free vibration problems of repetitive lattices. However, application of continuum modeling to nonlinear analysis needs more development. Reduction methods are very effective for bifurcation buckling and static (steady-state) nonlinear analysis. However, more work is needed to realize their full potential for nonlinear dynamic and time-dependent problems. As far as analysis and modeling needs are concerned, three areas are identified: loads determination, modeling and nonclassical behavior characteristics, and computational algorithms. The impact of new advances in computer hardware, software, integrated analysis, CAD/CAM stems, and materials technology is also discussed.

THE CURRENT METHODS FOR MOLECULAR DIAGNOSTICS OF FISH DISEASES (REVIEW

Directory of Open Access Journals (Sweden)

O. Zaloilo

2016-06-01

Full Text Available Purpose. The methods of molecular diagnostic (MMD gradually become widespread in modern fish farming. MMD contain a wide variety of specific approaches, each of which has distinct limits of their possible applications and is characterized by individual peculiarities in practical performance. In addition to high sensitivity and the possibility of rapid diagnostics, the main advantage of molecular methods is to determine the uncultivated infectious agents. DNA amplification allows identifying pathogenic microorganisms at very small quantities even in the minimum sample volume. Molecular methods of diagnostic enable the determination of infection in latent or acute phases. These methods allow showing the differences between pathogens with similar antigenic structures. The current literature data on this subject usually show a methodology in the narrow context of the tasks or practical results obtained through such approaches. Thus, a synthesis of existing information on the mechanisms of action and the limits of the typical problems of basic methods of molecular diagnostics are an urgent task of fish breeding. In particular, the following description will more effectively choose one or several approaches to identify pathogens in fish. Findings. This paper reviews the basic molecular methods that are used in the world's aquaculture for diagnosis of various diseases in commercial fish species. Originality. This work is a generalization of data on the principles and mechanisms for the implementation of diagnostics based on modern molecular techniques. For each of the mentioned approaches, the most promising areas of application were shown. The information is provided in the form of a comparative analysis of each methodology, indicating positive and negative practical aspects. Practical value. The current review of modern methods of molecular diagnostic in aquaculture is focused on practical application. Generalizing and analytical information can be

Review of assessment methods discount rate in investment analysis

Directory of Open Access Journals (Sweden)

Yamaletdinova Guzel Hamidullovna

2011-08-01

Full Text Available The article examines the current methods of calculating discount rate in investment analysis and business valuation, as well as analyzes the key problems using various techniques in terms of the Russian economy.

Current-voltage analysis of the record-efficiency CuGaSe2 solar cell: Application of the current separation method and the interface recombination model

International Nuclear Information System (INIS)

Saad, M.; Kasis, A.

2011-01-01

Current-voltage (j-V) characteristics of the record-efficiency CuGaSe 2 solar cell measured under several illumination levels are analyzed using a two-diode equation for a more accurate description of cell behavior. The contribution of each diode to the total cell j-V characteristic under illumination was estimated using the current separation method presented recently. This is performed in an effort to identify the distinctive features of this record-efficiency cell which have led to the up-to-date highest open circuit voltage of V o c = 946 mV and fill factor of FF = 66.5% for CuGaSe 2 solar cells. Furthermore, the interface recombination component of the cell current under illumination is quantitatively discussed applying the interface recombination model presented earlier. (author)

Effectiveness of the current method of calculating member states' contributions

CERN Document Server

2002-01-01

At its Two-hundred and eighty-sixth Meeting of 19 September 2001, the Finance Committee requested the Management to re-assess the effectiveness of the current method of forecasting Net National Income (NNI) for the purposes of calculating the Member States' contributions by comparing the results of the current weighted average method with a method based on a simple arithmetic average. The Finance Committee is invited to take note of this information.

Current status and trends, organizational methods accounting and analysis of innovative enterprises’ venture financing

Directory of Open Access Journals (Sweden)

S.V. Rudeychuk

2016-09-01

Full Text Available The article examines the specific features and tendencies of development of venture financing in Ukraine. It shows the role of venture capital in the further development of Ukraine economy, this role is in financing and development of innovation, distribution of new technologies and increase of employment of highly professional staff in the territory of Ukraine. The authors determine the influence of characteristics of such financing on the formation of organization and methods of accounting and economic analysis of operations with venture capital investments. The paper grounds the necessity of accounting development and analytical support of innovative enterprises’ venture financing management; the state is caused by the need to attract additional funding from venture investors to finance the production and release of innovative products and businesses. The authors determine the directions of solving problems in accounting organization and methods and economic analysis of innovative enterprises’ venture financing, respectively, for the needs of all entities doing business venture and taking into account the peculiarities of this type of investment capital.

Current methods of the analysis of immunosuppressive agents in clinical materials: A review.

Science.gov (United States)

Mika, Adriana; Stepnowski, Piotr

2016-08-05

More than 100000 solid organ transplantations are performed every year worldwide. Calcineurin (cyclosporine A, tacrolimus), serine/threonine kinase (sirolimus, everolimus) and inosine monophosphate dehydrogenase inhibitor (mycophenolate mofetil), are the most common drugs used as immunosuppressive agents after solid organ transplantation. Immunosuppressive therapy, although necessary after transplantation, is associated with many adverse consequences, including the formation of secondary metabolites of drugs and the induction of their side effects. Calcineurin inhibitors are associated with nephrotoxicity, cardiotoxicity and neurotoxicity; moreover, they increase the risk of many diseases after transplantation. The review presents a study of the movement of drugs in the body, including the processes of absorption, distribution, localisation in tissues, biotransformation and excretion, and also their accompanying side effects. Therefore, there is a necessity to monitor immunosuppressants, especially because these drugs are characterised by narrow therapeutic ranges. Their incorrect concentrations in a patient's blood could result in transplant rejection or in the accumulation of toxic effects. Immunosuppressive pharmaceuticals are macrolide lactones, peptides, and high molecular weight molecules that can be metabolised to several metabolites. Therefore the two main analytical methods used for their determination are high performance liquid chromatography with various detection methods and immunoassay methods. Despite the rapid development of new analytical methods of analysing immunosuppressive agents, the application of the latest generation of detectors and increasing sensitivity of such methods, there is still a great demand for the development of highly selective, sensitive, specific, rapid and relatively simple methods of immunosuppressive drugs analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

Analysis methods of stochastic transient electro–magnetic processes in electric traction system

Directory of Open Access Journals (Sweden)

T. M. Mishchenko

2013-04-01

Full Text Available Purpose. The essence and basic characteristics of calculation methods of transient electromagnetic processes in the elements and devices of non–linear dynamic electric traction systems taking into account the stochastic changes of voltages and currents in traction networks of power supply subsystem and power circuits of electric rolling stock are developed. Methodology. Classical methods and the methods of non–linear electric engineering, as well as probability theory method, especially the methods of stationary ergodic and non–stationary stochastic processes application are used in the research. Findings. Using the above-mentioned methods an equivalent circuit and the system of nonlinear integra–differential equations for electromagnetic condition of the double–track inter-substation zone of alternating current electric traction system are drawn up. Calculations allow obtaining electric traction current distribution in the areas of feeder zones. Originality. First of all the paper is interesting and important from scientific point of view due to the methods, which allow taking into account probabilistic character of change for traction voltages and electric traction system currents. On the second hand the researches develop the most efficient methods of nonlinear circuits’ analysis. Practical value. The practical value of the research is presented in application of the methods to the analysis of electromagnetic and electric energy processes in the traction power supply system in the case of high-speed train traffic.

Analysis and comparison of biometric methods

OpenAIRE

Zatloukal, Filip

2011-01-01

The thesis deals with biometrics and biometric systems and the possibility to use these systems in the enterprise. Aim of this study is an analysis and description of selected types of biometric identification methods and their advantages and shortcomings. The work is divided into two parts. The first part is theoretical, describes the basic concepts of biometrics, biometric identification criteria, currently used identification systems, the ways of biometric systems use, performance measurem...

Frequency scanning-based stability analysis method for grid-connected inverter system

DEFF Research Database (Denmark)

Wang, Yanbo; Wang, Xiongfei; Blaabjerg, Frede

2017-01-01

This paper proposes a frequency scanning-based impedance analysis for stability assessment of grid-connected inverter system, which is able to perform stability assessment without using system mathematical models and inherit the superior feature of impedance-based stability criterion with conside......This paper proposes a frequency scanning-based impedance analysis for stability assessment of grid-connected inverter system, which is able to perform stability assessment without using system mathematical models and inherit the superior feature of impedance-based stability criterion...... with consideration of the inverter nonlinearities. Small current disturbance is injected into grid-connected inverter system in a particular frequency range, and the impedance is computed according to the harmonic-frequency response using Fourier analysis, and then the stability is predicted on the basis...... of the impedance stability criterion. The stability issues of grid-connected inverters with grid-current feedback and the converter-current feedback are addressed using the proposed method. The results obtained from simulation and experiments validate the effectiveness of the method. The frequency scanning...

The necessity of improvement for the current LWR fuel assembly homogenization method

International Nuclear Information System (INIS)

Tang Chuntao; Huang Hao; Zhang Shaohong

2007-01-01

When the modern LWR core analysis method is used to do core nuclear design and in-core fuel management calculation, how to accurately obtain the fuel assembly homogenized parameters is a crucial issue. In this paper, taking the NEA C5G7-MOX benchmark problem as a severe test problem, which involves low-enriched uranium assemblies interspersed with MOX assemblies, we have re-examined the applicability of the two major assumptions of the modern equivalence theory for fuel assembly homoge- nization, i.e. the isolated assembly spatial spectrum assumption and the condensed two- group representation assumption. Numerical results have demonstrated that for LWR cores with strong spectrum interaction, both of these two assumptions are no longer applicable and the improvement for the homogenization method is necessary, the current two-group representation should be improved by the multigroup representation and the current reflective assembly boundary condition should be improved by the 'real' assembly boundary condition. This is a research project supported by National Natural Science Foundation of China (10605016). (authors)

Magnetic Method to Characterize the Current Densities in Breaker Arc

International Nuclear Information System (INIS)

Machkour, Nadia

2005-01-01

The purpose of this research was to use magnetic induction measurements from a low voltage breaker arc, to reconstruct the arc's current density. The measurements were made using Hall effect sensors, which were placed close to, but outside the breaking device. The arc was modelled as a rectangular current sheet, composed of a mix of threadlike current segments and with a current density varying across the propagation direction. We found the magnetic induction of the arc is a convolution product of the current density, and a function depending on the breaker geometry and arc model. Using deconvolution methods, the current density in the electric arc was determined.The method is used to study the arc behavior into the breaker device. Notably, position, arc size, and electric conductivity could all be determined, and then used to characterize the arc mode, diffuse or concentrated, and study the condition of its mode changing

Current-drive theory I: survey of methods

International Nuclear Information System (INIS)

Fisch, N.J.

1986-01-01

A variety of methods may be employed to drive toroidal electric current in a plasma torus. The most promising scheme is the injection of radiofrequency waves into the torus to push electrons or ions. The pushing mechanism can be either the direct conversion of wave to particle momentum, or a more subtle effect involving the alteration by waves of interparticle collisions. Alternatively, current can be produced through the injection of neutral beams, the reflection of plasma radiation, or the injection of frozen pellets. The efficacy of these schemes, in a variety of regimes, will be assessed. 9 refs

Numerical investigations on contactless methods for measuring critical current density in HTS: application of modified constitutive-relation method

International Nuclear Information System (INIS)

Kamitani, A.; Takayama, T.; Itoh, T.; Ikuno, S.

2011-01-01

A fast method is proposed for calculating the shielding current density in an HTS. The J-E constitutive relation is modified so as not to change the solution. A numerical code is developed on the basis of the proposed method. The permanent magnet method is successfully simulated by means of the code. A fast method has been proposed for calculating the shielding current density in a high-temperature superconducting thin film. An initial-boundary-value problem of the shielding current density cannot be always solved by means of the Runge-Kutta method even when an adaptive step-size control algorithm is incorporated to the method. In order to suppress an overflow in the algorithm, the J-E constitutive relation is modified so that its solution may satisfy the original constitutive relation. A numerical code for analyzing the shielding current density has been developed on the basis of this method and, as an application of the code, the permanent magnet method for measuring the critical current density has been investigated numerically.

Spatial Analysis Methods of Road Traffic Collisions

DEFF Research Database (Denmark)

Loo, Becky P. Y.; Anderson, Tessa Kate

Spatial Analysis Methods of Road Traffic Collisions centers on the geographical nature of road crashes, and uses spatial methods to provide a greater understanding of the patterns and processes that cause them. Written by internationally known experts in the field of transport geography, the book...... outlines the key issues in identifying hazardous road locations (HRLs), considers current approaches used for reducing and preventing road traffic collisions, and outlines a strategy for improved road safety. The book covers spatial accuracy, validation, and other statistical issues, as well as link...

Determination of metal impurities in MOX powder by direct current arc atomic emission spectroscopy. Application of standard addition method for direct analysis of powder sample

International Nuclear Information System (INIS)

Furuse, Takahiro; Taguchi, Shigeo; Kuno, Takehiko; Surugaya, Naoki

2016-12-01

Metal impurities in MOX powder obtained from uranium and plutonium recovered from reprocessing process of spent nuclear fuel have to be determined for its characterization. Direct current arc atomic emission spectroscopy (DCA-AES) is one of the useful methods for direct analysis of powder sample without dissolving the analyte into aqueous solution. However, the selection of standard material, which can overcome concerns such as matrix matching, is quite important to create adequate calibration curves for DCA-AES. In this study, we apply standard addition method using the certified U_3O_8 containing known amounts of metal impurities to avoid the matrix problems. The proposed method provides good results for determination of Fe, Cr and Ni contained in MOX samples at a significant quantity level. (author)

Evaluation of Circulating Current Suppression Methods for Parallel Interleaved Inverters

DEFF Research Database (Denmark)

Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Teodorescu, Remus

2016-01-01

Two-level Voltage Source Converters (VSCs) are often connected in parallel to achieve desired current rating in multi-megawatt Wind Energy Conversion System (WECS). A multi-level converter can be realized by interleaving the carrier signals of the parallel VSCs. As a result, the harmonic perfor......-mance of the WECS can be significantly improved. However, the interleaving of the carrier signals may lead to the flow of circulating current between parallel VSCs and it is highly desirable to avoid/suppress this unwanted circulating current. A comparative evaluation of the different methods to avoid....../suppress the circulating current between the parallel interleaved VSCs is presented in this paper. The losses and the volume of the inductive components and the semiconductor losses are evaluated for the WECS with different circulating current suppression methods. Multi-objective optimizations of the inductive components...

Harmonic Stability Analysis of Offshore Wind Farm with Component Connection Method

DEFF Research Database (Denmark)

Hou, Peng; Ebrahimzadeh, Esmaeil; Wang, Xiongfei

2017-01-01

In this paper, an eigenvalue-based harmonic stability analysis method for offshore wind farm is proposed. Considering the internal cable connection layout, a component connection method (CCM) is adopted to divide the system into individual blocks as current controller of converters, LCL filters...

Current opinion about maximum entropy methods in Moessbauer spectroscopy

International Nuclear Information System (INIS)

Szymanski, K

2009-01-01

Current opinion about Maximum Entropy Methods in Moessbauer Spectroscopy is presented. The most important advantage offered by the method is the correct data processing under circumstances of incomplete information. Disadvantage is the sophisticated algorithm and its application to the specific problems.

Wavelet analysis of nonstationary fluctuations of Monte Carlo-simulated excitatory postsynaptic currents.

Science.gov (United States)

Aristizabal, F; Glavinovic, M I

2003-10-01

Tracking spectral changes of rapidly varying signals is a demanding task. In this study, we explore on Monte Carlo-simulated glutamate-activated AMPA patch and synaptic currents whether a wavelet analysis offers such a possibility. Unlike Fourier methods that determine only the frequency content of a signal, the wavelet analysis determines both the frequency and the time. This is owing to the nature of the basis functions, which are infinite for Fourier transforms (sines and cosines are infinite), but are finite for wavelet analysis (wavelets are localized waves). In agreement with previous reports, the frequency of the stationary patch current fluctuations is higher for larger currents, whereas the mean-variance plots are parabolic. The spectra of the current fluctuations and mean-variance plots are close to the theoretically predicted values. The median frequency of the synaptic and nonstationary patch currents is, however, time dependent, though at the peak of synaptic currents, the median frequency is insensitive to the number of glutamate molecules released. Such time dependence demonstrates that the "composite spectra" of the current fluctuations gathered over the whole duration of synaptic currents cannot be used to assess the mean open time or effective mean open time of AMPA channels. The current (patch or synaptic) versus median frequency plots show hysteresis. The median frequency is thus not a simple reflection of the overall receptor saturation levels and is greater during the rise phase for the same saturation level. The hysteresis is due to the higher occupancy of the doubly bound state during the rise phase and not due to the spatial spread of the saturation disk, which remains remarkably constant. Albeit time dependent, the variance of the synaptic and nonstationary patch currents can be accurately determined. Nevertheless the evaluation of the number of AMPA channels and their single current from the mean-variance plots of patch or synaptic

Improvement of Power Flow Calculation with Optimization Factor Based on Current Injection Method

Directory of Open Access Journals (Sweden)

Lei Wang

2014-01-01

Full Text Available This paper presents an improvement in power flow calculation based on current injection method by introducing optimization factor. In the method proposed by this paper, the PQ buses are represented by current mismatches while the PV buses are represented by power mismatches. It is different from the representations in conventional current injection power flow equations. By using the combined power and current injection mismatches method, the number of the equations required can be decreased to only one for each PV bus. The optimization factor is used to improve the iteration process and to ensure the effectiveness of the improved method proposed when the system is ill-conditioned. To verify the effectiveness of the method, the IEEE test systems are tested by conventional current injection method and the improved method proposed separately. Then the results are compared. The comparisons show that the optimization factor improves the convergence character effectively, especially that when the system is at high loading level and R/X ratio, the iteration number is one or two times less than the conventional current injection method. When the overloading condition of the system is serious, the iteration number in this paper appears 4 times less than the conventional current injection method.

Electromotive force analysis of current transformer during lightning surge inflow using Fourier series expansion

Directory of Open Access Journals (Sweden)

Youngsun Kim

2017-05-01

Full Text Available The most common structure used for current transformers (CTs consists of secondary windings around a ferromagnetic core past the primary current being measured. A CT used as a surge protection device (SPD may experience large inrushes of current, like surges. However, when a large current flows into the primary winding, measuring the magnitude of the current is difficult because the ferromagnetic core becomes magnetically saturated. Several approaches to reduce the saturation effect are described in the literature. A Rogowski coil is representative of several devices that measure large currents. It is an electrical device that measures alternating current (AC or high-frequency current. However, such devices are very expensive in application. In addition, the volume of a CT must be increased to measure sufficiently large currents, but for installation spaces that are too small, other methods must be used. To solve this problem, it is necessary to analyze the magnetic field and electromotive force (EMF characteristics when designing a CT. Thus, we proposed an analysis method for the CT under an inrush current using the time-domain finite element method (TDFEM. The input source current of a surge waveform is expanded by a Fourier series to obtain an instantaneous value. An FEM model of the device is derived in a two-dimensional system and coupled with EMF circuits. The time-derivative term in the differential equation is solved in each time step by the finite difference method. It is concluded that the proposed algorithm is useful for analyzing CT characteristics, including the field distribution. Consequently, the proposed algorithm yields a reference for obtaining the effects of design parameters and magnetic materials for special shapes and sizes before the CT is designed and manufactured.

Electromotive force analysis of current transformer during lightning surge inflow using Fourier series expansion

Science.gov (United States)

Kim, Youngsun

2017-05-01

The most common structure used for current transformers (CTs) consists of secondary windings around a ferromagnetic core past the primary current being measured. A CT used as a surge protection device (SPD) may experience large inrushes of current, like surges. However, when a large current flows into the primary winding, measuring the magnitude of the current is difficult because the ferromagnetic core becomes magnetically saturated. Several approaches to reduce the saturation effect are described in the literature. A Rogowski coil is representative of several devices that measure large currents. It is an electrical device that measures alternating current (AC) or high-frequency current. However, such devices are very expensive in application. In addition, the volume of a CT must be increased to measure sufficiently large currents, but for installation spaces that are too small, other methods must be used. To solve this problem, it is necessary to analyze the magnetic field and electromotive force (EMF) characteristics when designing a CT. Thus, we proposed an analysis method for the CT under an inrush current using the time-domain finite element method (TDFEM). The input source current of a surge waveform is expanded by a Fourier series to obtain an instantaneous value. An FEM model of the device is derived in a two-dimensional system and coupled with EMF circuits. The time-derivative term in the differential equation is solved in each time step by the finite difference method. It is concluded that the proposed algorithm is useful for analyzing CT characteristics, including the field distribution. Consequently, the proposed algorithm yields a reference for obtaining the effects of design parameters and magnetic materials for special shapes and sizes before the CT is designed and manufactured.

A Comparative Study of Voltage, Peak Current and Dual Current Mode Control Methods for Noninverting Buck-Boost Converter

Directory of Open Access Journals (Sweden)

M. Č. Bošković

2016-06-01

Full Text Available This paper presents a comparison of voltage mode control (VMC and two current mode control (CMC methods of noninverting buck-boost converter. The converter control-to-output transfer function, line-to-output transfer function and the output impedance are obtained for all methods by averaging converter equations over one switching period and applying small-signal linearization. The obtained results are required for the design procedure of feedback compensator to keep a system stable and robust. A comparative study of VMC, peak current mode control (PCMC and dual-current mode control (DCMC is performed. Performance evaluation of the closed-loop system with obtained compensator between these methods is performed via numerical simulations.

Determination of mycotoxins in foods: current state of analytical methods and limitations.

Science.gov (United States)

Köppen, Robert; Koch, Matthias; Siegel, David; Merkel, Stefan; Maul, Ronald; Nehls, Irene

2010-05-01

Mycotoxins are natural contaminants produced by a range of fungal species. Their common occurrence in food and feed poses a threat to the health of humans and animals. This threat is caused either by the direct contamination of agricultural commodities or by a "carry-over" of mycotoxins and their metabolites into animal tissues, milk, and eggs after feeding of contaminated hay or corn. As a consequence of their diverse chemical structures and varying physical properties, mycotoxins exhibit a wide range of biological effects. Individual mycotoxins can be genotoxic, mutagenic, carcinogenic, teratogenic, and oestrogenic. To protect consumer health and to reduce economic losses, surveillance and control of mycotoxins in food and feed has become a major objective for producers, regulatory authorities and researchers worldwide. However, the variety of chemical structures makes it impossible to use one single technique for mycotoxin analysis. Hence, a vast number of analytical methods has been developed and validated. The heterogeneity of food matrices combined with the demand for a fast, simultaneous and accurate determination of multiple mycotoxins creates enormous challenges for routine analysis. The most crucial issues will be discussed in this review. These are (1) the collection of representative samples, (2) the performance of classical and emerging analytical methods based on chromatographic or immunochemical techniques, (3) the validation of official methods for enforcement, and (4) the limitations and future prospects of the current methods.

A Modified Droop Control Method for Parallel-Connected Current Source Inverters

DEFF Research Database (Denmark)

Wei, Baoze; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

2016-01-01

In this paper, a novel control method was proposed for current source inverters under the grid-connected working mode. The control scheme is based on a modified droop control method, with an additional current reference signal that will be generated instead of the voltage reference. Hence......, there is only a current control loop with droop control in the whole control scheme without voltage control loop. So it is very suitable for grid-connected current source inverter which will simplify the design of the control scheme and combine the advantage of droop control. The parallel configuration...... is widely used to acquire high power demand, but the circulating current problem is a key issue that should be considered. In this paper, a simulation based on parallel current source inverters using the proposed control scheme is provided. Simulation results showed that a good circulating current...

Method for controlling low-energy high current density electron beams

International Nuclear Information System (INIS)

Lee, J.N.; Oswald, R.B. Jr.

1977-01-01

A method and an apparatus for controlling the angle of incidence of low-energy, high current density electron beams are disclosed. The apparatus includes a current generating diode arrangement with a mesh anode for producing a drifting electron beam. An auxiliary grounded screen electrode is placed between the anode and a target for controlling the average angle of incidence of electrons in the drifting electron beam. According to the method of the present invention, movement of the auxiliary screen electrode relative to the target and the anode permits reliable and reproducible adjustment of the average angle of incidence of the electrons in low energy, high current density relativistic electron beams

Automatic Condition Monitoring of Industrial Rolling-Element Bearings Using Motor’s Vibration and Current Analysis

DEFF Research Database (Denmark)

Yang, Zhenyu

2015-01-01

An automatic condition monitoring for a class of industrial rolling-element bearings is developed based on the vibration as well as stator current analysis. The considered fault scenarios include a single-point defect, multiple-point defects, and a type of distributed defect. Motivated by the pot...... characteristic frequencies, sideband effects, time-average of spectra, and selection of fault index and thresholds, are also discussed. The experimental work shows a huge potential to use some simple methods for successful diagnosis of industrial bearing systems.......An automatic condition monitoring for a class of industrial rolling-element bearings is developed based on the vibration as well as stator current analysis. The considered fault scenarios include a single-point defect, multiple-point defects, and a type of distributed defect. Motivated...... is extensively studied under diverse operating conditions: different sensor locations, motor speeds, loading conditions, and data samples from different time segments. The experimental results showed the powerful capability of vibration analysis in the bearing point defect fault diagnosis. The current analysis...

The integral equation method applied to eddy currents

International Nuclear Information System (INIS)

Biddlecombe, C.S.; Collie, C.J.; Simkin, J.; Trowbridge, C.W.

1976-04-01

An algorithm for the numerical solution of eddy current problems is described, based on the direct solution of the integral equation for the potentials. In this method only the conducting and iron regions need to be divided into elements, and there are no boundary conditions. Results from two computer programs using this method for iron free problems for various two-dimensional geometries are presented and compared with analytic solutions. (author)

Damping Methods for Resonances Caused by LCL-Filter-Based Current-Controlled Grid-Tied Power Inverters

DEFF Research Database (Denmark)

Wu, Weimin; Liu, Yuan; He, Yuanbin

2017-01-01

Grid-tied voltage source inverters using LCL filter have been widely adopted in distributed power generation systems (DPGSs). As high-order LCL filters contain multiple resonant frequencies, switching harmonics generated by the inverter and current harmonics generated by the active/passive loads...... innovative damping methods have been proposed. A comprehensive overview on those contributions and their classification on the inverter- and grid-side damping measures are presented. Based on the concept of the impedance-based stability analysis, all damping methods can ensure the system stability...

Probabilistic methods in fire-risk analysis

International Nuclear Information System (INIS)

Brandyberry, M.D.

1989-01-01

The first part of this work outlines a method for assessing the frequency of ignition of a consumer product in a building and shows how the method would be used in an example scenario utilizing upholstered furniture as the product and radiant auxiliary heating devices (electric heaters, wood stoves) as the ignition source. Deterministic thermal models of the heat-transport processes are coupled with parameter uncertainty analysis of the models and with a probabilistic analysis of the events involved in a typical scenario. This leads to a distribution for the frequency of ignition for the product. In second part, fire-risk analysis as currently used in nuclear plants is outlines along with a discussion of the relevant uncertainties. The use of the computer code COMPBRN is discussed for use in the fire-growth analysis along with the use of response-surface methodology to quantify uncertainties in the code's use. Generalized response surfaces are developed for temperature versus time for a cable tray, as well as a surface for the hot gas layer temperature and depth for a room of arbitrary geometry within a typical nuclear power plant compartment. These surfaces are then used to simulate the cable tray damage time in a compartment fire experiment

Robust method for stator current reconstruction from DC link in a ...

African Journals Online (AJOL)

Using the switching signals and dc link current, this paper presents a new algorithm for the reconstruction of stator currents of an inverter-fed, three-phase induction motor drive. Unlike the classical and improved methods available in literature, the proposed method is neither based on pulse width modulation pattern ...

COMPARATIVE ANALYSIS OF EXERGETIC BALANCE METHODS IN ALCOHOLIC DISTILLATION COLUMNS

Directory of Open Access Journals (Sweden)

Arletis Cruz Llerena

2017-04-01

Full Text Available The comparison between three methods to calculate the exergy of the currents involved in the exergetic balance of alcoholic distillation columns is presented. Exergy of the currents was considered as: 1 flow exergies, 2 heat exergies and 3 the sum of flow exergy and chemical exergy. The implementation of the exergetic analysis was examined as a key point to improve the efficiency of the process. A case study, where the methods are applied for the evaluation of the exergy is analyzed; differences among the methods were obtained between the 15% and 30 %. The influence of the studied columns in total work capacity loss was determined, concluding that regardless of the method, the distillation column has shown the higher loss. An economic analysis was made applying the first method to the case study, where the percentage of ethanol in wine increases from 5.8 ºGL to 9 ºGL, which led to a decrease of vapor consumption of 23.66%, an exergetic yield increase of 28.02 % and a combustion gas flow reduction of 24 627 034.4 m3/year.

Steam generator automated eddy current data analysis: A benchmarking study. Final report

International Nuclear Information System (INIS)

Brown, S.D.

1998-12-01

The eddy current examination of steam generator tubes is a very demanding process. Challenges include: complex signal analysis, massive amount of data to be reviewed quickly with extreme precision and accuracy, shortages of data analysts during peak periods, and the desire to reduce examination costs. One method to address these challenges is by incorporating automation into the data analysis process. Specific advantages, which automated data analysis has the potential to provide, include the ability to analyze data more quickly, consistently and accurately than can be performed manually. Also, automated data analysis can potentially perform the data analysis function with significantly smaller levels of analyst staffing. Despite the clear advantages that an automated data analysis system has the potential to provide, no automated system has been produced and qualified that can perform all of the functions that utility engineers demand. This report investigates the current status of automated data analysis, both at the commercial and developmental level. A summary of the various commercial and developmental data analysis systems is provided which includes the signal processing methodologies used and, where available, the performance data obtained for each system. Also, included in this report is input from seventeen research organizations regarding the actions required and obstacles to be overcome in order to bring automatic data analysis from the laboratory into the field environment. In order to provide assistance with ongoing and future research efforts in the automated data analysis arena, the most promising approaches to signal processing are described in this report. These approaches include: wavelet applications, pattern recognition, template matching, expert systems, artificial neural networks, fuzzy logic, case based reasoning and genetic algorithms. Utility engineers and NDE researchers can use this information to assist in developing automated data

Data Analysis Methods for Paleogenomics

DEFF Research Database (Denmark)

Avila Arcos, Maria del Carmen

(Danmarks Grundforskningfond) 'Centre of Excellence in GeoGenetics' grant, with additional funding provided by the Danish Council for Independent Research 'Sapere Aude' programme. The thesis comprises five chapters, all of which represent different projects that involved the analysis of massive amounts......, thanks to the introduction of NGS and the implementation of data analysis methods specific for each project. Chapters 1 to 3 have been published in peer-reviewed journals and Chapter 4 is currently in review. Chapter 5 consists of a manuscript describing initial results of an ongoing research project......The work presented in this thesis is the result of research carried out during a three-year PhD at the Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, under supervision of Professor Tom Gilbert. The PhD was funded by the Danish National Research Foundation...

A Technique to Estimate the Equivalent Loss Resistance of Grid-Tied Converters for Current Control Analysis and Design

DEFF Research Database (Denmark)

Vidal, Ana; Yepes, Alejandro G.; Fernandez, Francisco Daniel Freijedo

2015-01-01

Rigorous analysis and design of the current control loop in voltage source converters (VSCs) requires an accurate modeling. The loop behavior can be significantly influenced by the VSC working conditions. To consider such effect, converter losses should be included in the model, which can be done...... by means of an equivalent series resistance. This paper proposes a method to identify the VSC equivalent loss resistance for the proper tuning of the current control loop. It is based on analysis of the closed-loop transient response provided by a synchronous proportional-integral current controller......, according to the internal model principle. The method gives a set of loss resistance values linked to working conditions, which can be used to improve the tuning of the current controllers, either by online adaptation of the controller gains or by open-loop adaptive adjustment of them according to prestored...

Finite element transport methods for criticality calculations - current status and potential applications

International Nuclear Information System (INIS)

Oliveira, C.R.E. de; Goddard, A.

1991-01-01

In this paper we review the current status of the finite element method applied to the solution of the neutron transport equation and we discuss its potential role in the field of criticality safety. We show that the method's ability in handling complex, irregular geometry in two- and three-dimensions coupled with its accurate solutions potentially renders it an attractive alternative to the longer-established Monte Carlo method. Details of the most favoured form of the method - that which combines finite elements in space and spherical harmonics in angle - are presented. This form of the method, which has been extensively investigated over the last decade by research groups at the University of London, has been numerically implemented in the finite element code EVENT. The code has among its main features the capability of solving fixed source eigenvalue and time-dependent complex geometry problems in two- and three-dimensions. Other features of the code include anisotropic up- and down-scatter, direct and/or adjoint solutions and access to standard data libraries. Numerical examples, ranging from simple criticality benchmark studies to the analysis of idealised three-dimensional reactor cores, are presented to demonstrate the potential of the method. (author)

Current lung water measurement methods in man

International Nuclear Information System (INIS)

Basset, G.; Moreau, F.; Marsac, J.; Capitini, R.; Botter, F.

1979-01-01

Two kinds of tracer method are used to estimate the lung water pools differing by the tracer intake and the sector observed. Airborne intake gives an estimate of the tissues irrigated by the lung and bronchial circulation, whereas vascular intake only shows the sectors perfused by the lung flow. Either of these methods is suitable for a general or regional analysis. In general methods the tracer is followed at the lung exit on expired air for the first method, on peripheral arterial blood for the second. Regional methods imply partial or whole-lung external detection systems [fr

Eddy current analysis by BEM utilizing loop electric and surface magnetic currents as unknowns

International Nuclear Information System (INIS)

Ishibashi, Kazuhisa

2002-01-01

The surface integral equations whose unknowns are the surface electric and magnetic currents are widely used in eddy current analysis. However, when the skin depth is thick, computational error is increased especially in obtaining electromagnetic fields near the edge of the conductor. In order to obtain the electromagnetic field accurately, we propose an approach to solve surface integral equations utilizing loop electric and surface magnetic currents as unknowns. (Author)

Second Ripple Current Suppression by Two Bandpass Filters and Current Sharing Method for Energy Storage Converters in DC Microgrid

DEFF Research Database (Denmark)

Yang, Ling; Chen, Yandong; Luo, An

2017-01-01

With the increasing of AC loads injected into DC microgird (MG) through the inverters, the second ripple current (SRC) in the front-end energy storage converter (ESC) and circulating current among the ESCs in DC MG become more and more serious. In this paper, the SRC suppression method by introdu......With the increasing of AC loads injected into DC microgird (MG) through the inverters, the second ripple current (SRC) in the front-end energy storage converter (ESC) and circulating current among the ESCs in DC MG become more and more serious. In this paper, the SRC suppression method...

Security analysis and improvements to the PsychoPass method.

Science.gov (United States)

Brumen, Bostjan; Heričko, Marjan; Rozman, Ivan; Hölbl, Marko

2013-08-13

In a recent paper, Pietro Cipresso et al proposed the PsychoPass method, a simple way to create strong passwords that are easy to remember. However, the method has some security issues that need to be addressed. To perform a security analysis on the PsychoPass method and outline the limitations of and possible improvements to the method. We used the brute force analysis and dictionary attack analysis of the PsychoPass method to outline its weaknesses. The first issue with the Psychopass method is that it requires the password reproduction on the same keyboard layout as was used to generate the password. The second issue is a security weakness: although the produced password is 24 characters long, the password is still weak. We elaborate on the weakness and propose a solution that produces strong passwords. The proposed version first requires the use of the SHIFT and ALT-GR keys in combination with other keys, and second, the keys need to be 1-2 distances apart. The proposed improved PsychoPass method yields passwords that can be broken only in hundreds of years based on current computing powers. The proposed PsychoPass method requires 10 keys, as opposed to 20 keys in the original method, for comparable password strength.

IEDA [Intelligent Eddy Current Data Analysis] helps make sense of eddy current data [steam generators

International Nuclear Information System (INIS)

Clark, R.

1989-01-01

The increasing sophistication of eddy current signal interpretation in steam generator tubing has improved capabilities, but has also made the process of analysis more complex and time consuming. Westinghouse has developed an intelligent computerised tool - the IEDA (Intelligent Eddy Current Data Analysis) system, to lighten the load on analysts. Since 1985, 44 plants have been inspected with IEDA, representing over 400,000 tubes. The system has provided a repeatability and a consistency not achieved by human operators. (U.K.)

HIRFL-SSC trim coil currents calculation by conjugate gradients method

International Nuclear Information System (INIS)

Liu, W.

2005-01-01

For accelerating different kinds of ions to various energies, the HIRFL-SSC should form the corresponding isochronous magnetic field by its main coil and trim coils. Previously, there were errors in fitting the theoretical isochronous magnetic field in the small radius region, which led to some operation difficulties for ion acceleration in the inject region. After further investigation of the restrictive condition of the maximum current limitation, the trim coil currents for fitting the theoretical isochronous magnetic field were recalculated by the conjugate gradients method. Better results were obtained in the operation of HIRFL-SSC. This article introduces the procedure to calculate the trim coil currents. The calculation method of conjugate gradients is introduced and the fitting error is analysed. (author)

Overview of methods for uncertainty analysis and sensitivity analysis in probabilistic risk assessment

International Nuclear Information System (INIS)

Iman, R.L.; Helton, J.C.

1985-01-01

Probabilistic Risk Assessment (PRA) is playing an increasingly important role in the nuclear reactor regulatory process. The assessment of uncertainties associated with PRA results is widely recognized as an important part of the analysis process. One of the major criticisms of the Reactor Safety Study was that its representation of uncertainty was inadequate. The desire for the capability to treat uncertainties with the MELCOR risk code being developed at Sandia National Laboratories is indicative of the current interest in this topic. However, as yet, uncertainty analysis and sensitivity analysis in the context of PRA is a relatively immature field. In this paper, available methods for uncertainty analysis and sensitivity analysis in a PRA are reviewed. This review first treats methods for use with individual components of a PRA and then considers how these methods could be combined in the performance of a complete PRA. In the context of this paper, the goal of uncertainty analysis is to measure the imprecision in PRA outcomes of interest, and the goal of sensitivity analysis is to identify the major contributors to this imprecision. There are a number of areas that must be considered in uncertainty analysis and sensitivity analysis for a PRA: (1) information, (2) systems analysis, (3) thermal-hydraulic phenomena/fission product behavior, (4) health and economic consequences, and (5) display of results. Each of these areas and the synthesis of them into a complete PRA are discussed

A method for data base management and analysis for wind tunnel data

Science.gov (United States)

Biser, Aileen O.

1987-01-01

To respond to the need for improved data base management and analysis capabilities for wind-tunnel data at the Langley 16-Foot Transonic Tunnel, research was conducted into current methods of managing wind-tunnel data and a method was developed as a solution to this need. This paper describes the development of the data base management and analysis method for wind-tunnel data. The design and implementation of the software system are discussed and examples of its use are shown.

Current Mathematical Methods Used in QSAR/QSPR Studies

Directory of Open Access Journals (Sweden)

Peixun Liu

2009-04-01

Full Text Available This paper gives an overview of the mathematical methods currently used in quantitative structure-activity/property relationship (QASR/QSPR studies. Recently, the mathematical methods applied to the regression of QASR/QSPR models are developing very fast, and new methods, such as Gene Expression Programming (GEP, Project Pursuit Regression (PPR and Local Lazy Regression (LLR have appeared on the QASR/QSPR stage. At the same time, the earlier methods, including Multiple Linear Regression (MLR, Partial Least Squares (PLS, Neural Networks (NN, Support Vector Machine (SVM and so on, are being upgraded to improve their performance in QASR/QSPR studies. These new and upgraded methods and algorithms are described in detail, and their advantages and disadvantages are evaluated and discussed, to show their application potential in QASR/QSPR studies in the future.

Resistivity measurements using a direct current induction method (1963)

International Nuclear Information System (INIS)

Delaplace, J.; Hillairet, J.

1964-01-01

The conventional methods for measuring electrical resistivities necessitate the fixing of electrical contacts on the sample either mechanically or by soldering. Furthermore it is also necessary to carry,out the measurements on low cross-section samples which are not always easy to obtain. Our direct-current induction method on the other hand requires no contacts and can easily be applied to samples of large cross-section. The sample is placed in a uniform magnetic field; at the moment when the current is cut, eddy currents appear in the sample which tend to oppose the disappearance of the field. The way in which the magnetic flux decreases in the sample makes it possible to determine the resistivity of the material. This method has been applied to samples having diameters of between 1 and 30 mm in the case of metals which are good conductors. It gives a value for the local resistivity and makes it possible to detect any variation along a sample. The measurements can be carried out at all temperature from a few degrees absolute to 500 deg. C. We have used the induction method to follow the purification of beryllium by zone-melting; it is in effect possible to estimate the purity of a material by resistivity measurements. We have measured the resistivity along each bar treated by the zone-melting technique and have thus, localised the purest section. High temperature measurements have been carried out on uranium carbide and on iron-aluminium alloys. This method constitutes an interesting means of investigation the resistivity of solid materials. Its accuracy and rapidity make it particularly adapted both to fundamental research and to production control. (authors) [fr

A Combined Experimental and Finite Element Analysis Method for the Estimation of Eddy-Current Loss in NdFeB Magnets

Directory of Open Access Journals (Sweden)

Radu Fratila

2014-05-01

Full Text Available NdFeB permanent magnets (PMs are widely used in high performance electrical machines, but their relatively high conductivity subjects them to eddy current losses that can lead to magnetization loss. The Finite Element (FE method is generally used to quantify the eddy current loss of PMs, but it remains quite difficult to validate the accuracy of the results with complex devices. In this paper, an experimental test device is used in order to extract the eddy current losses that are then compared with those of a 3D FE model.

A combined experimental and finite element analysis method for the estimation of eddy-current loss in NdFeB magnets.

Science.gov (United States)

Fratila, Radu; Benabou, Abdelkader; Tounzi, Abdelmounaïm; Mipo, Jean-Claude

2014-05-14

NdFeB permanent magnets (PMs) are widely used in high performance electrical machines, but their relatively high conductivity subjects them to eddy current losses that can lead to magnetization loss. The Finite Element (FE) method is generally used to quantify the eddy current loss of PMs, but it remains quite difficult to validate the accuracy of the results with complex devices. In this paper, an experimental test device is used in order to extract the eddy current losses that are then compared with those of a 3D FE model.

Longitudinal data analysis a handbook of modern statistical methods

CERN Document Server

Fitzmaurice, Garrett; Verbeke, Geert; Molenberghs, Geert

2008-01-01

Although many books currently available describe statistical models and methods for analyzing longitudinal data, they do not highlight connections between various research threads in the statistical literature. Responding to this void, Longitudinal Data Analysis provides a clear, comprehensive, and unified overview of state-of-the-art theory and applications. It also focuses on the assorted challenges that arise in analyzing longitudinal data. After discussing historical aspects, leading researchers explore four broad themes: parametric modeling, nonparametric and semiparametric methods, joint

A Steel Ball Surface Quality Inspection Method Based on a Circumferential Eddy Current Array Sensor.

Science.gov (United States)

Zhang, Huayu; Xie, Fengqin; Cao, Maoyong; Zhong, Mingming

2017-07-01

To efficiently inspect surface defects on steel ball bearings, a new method based on a circumferential eddy current array (CECA) sensor was proposed here. The best probe configuration, in terms of the coil quality factor (Q-factor), magnetic field intensity, and induced eddy current density on the surface of a sample steel ball, was determined using 3-, 4-, 5-, and 6-coil probes, for analysis and comparison. The optimal lift-off from the measured steel ball, the number of probe coils, and the frequency of excitation current suitable for steel ball inspection were obtained. Using the resulting CECA sensor to inspect 46,126 steel balls showed a miss rate of ~0.02%. The sensor was inspected for surface defects as small as 0.05 mm in width and 0.1 mm in depth.

Motor current signature analysis for gearbox condition monitoring under transient speeds using wavelet analysis and dual-level time synchronous averaging

Science.gov (United States)

Bravo-Imaz, Inaki; Davari Ardakani, Hossein; Liu, Zongchang; García-Arribas, Alfredo; Arnaiz, Aitor; Lee, Jay

2017-09-01

This paper focuses on analyzing motor current signature for fault diagnosis of gearboxes operating under transient speed regimes. Two different strategies are evaluated, extensively tested and compared to analyze the motor current signature in order to implement a condition monitoring system for gearboxes in industrial machinery. A specially designed test bench is used, thoroughly monitored to fully characterize the experiments, in which gears in different health status are tested. The measured signals are analyzed using discrete wavelet decomposition, in different decomposition levels using a range of mother wavelets. Moreover, a dual-level time synchronous averaging analysis is performed on the same signal to compare the performance of the two methods. From both analyses, the relevant features of the signals are extracted and cataloged using a self-organizing map, which allows for an easy detection and classification of the diverse health states of the gears. The results demonstrate the effectiveness of both methods for diagnosing gearbox faults. A slightly better performance was observed for dual-level time synchronous averaging method. Based on the obtained results, the proposed methods can used as effective and reliable condition monitoring procedures for gearbox condition monitoring using only motor current signature.

Read method compensating parasitic sneak currents in a crossbar memristive memory

KAUST Repository

Zidan, Mohammed A.

2017-03-02

Methods are provided for mitigating problems caused by sneak- paths current during memory cell access in gateless arrays. Example methods contemplated herein utilize adaptive-threshold readout techniques that utilize the locality and hierarchy properties of the computer memory system to address this sneak-paths problem. The method of the invention is a method for reading a target memory cell located at an intersection of a target row of a gateless array and a target column of the gateless array, the method comprising: -reading a value of the target memory cell; and -calculating an actual value of the target memory cell based on the read value of the memory cell and a component of the read value caused by sneak path current. Utilizing either an "initial bits" strategy or a "dummy bits" strategy in order to calculate the component of the read value caused by sneak path current, example embodiments significantly reduce the number of memory accesses pixel for an array readout. In addition, these strategies consume an order of magnitude less power in comparison to alternative state-of-the-art readout techniques.

Study program for constant current capacitor charging method

Energy Technology Data Exchange (ETDEWEB)

Pugh, C.

1978-10-04

The objective of the study program was to determine the best method of charging 20,000 to 132,000 microfarads of capacitance to 22 kVdc in 14 to 15 sec. Component costs, sizes, weights, line current graphs, copies of calculations and manufacturer's data are included.

Current status of fertility control methods in India

Indian Academy of Sciences (India)

Use of the condom increased to 3.1% from 2.4%. ... Current efforts in India to develop a male contraceptive are mainly directed towards ... the existing range of contraceptive methods available in the National Family Planning Programme. ... long acting, relatively easily removed and fertility returns rapidly after their removal.

Two numerical methods for the solution of two-dimensional eddy current problems

International Nuclear Information System (INIS)

Biddlecombe, C.S.

1978-07-01

A general method for the solution of eddy current problems in two dimensions - one component of current density and two of magnetic field, is reported. After examining analytical methods two numerical methods are presented. Both solve the two dimensional, low frequency limit of Maxwell's equations for transient eddy currents in conducting material, which may be permeable, in the presence of other non-conducting permeable material. Both solutions are expressed in terms of the magnetic vector potential. The first is an integral equation method, using zero order elements in the discretisation of the unknown source regions. The other is a differential equation method, using a first order finite element mesh, and the Galerkin weighted residual procedure. The resulting equations are solved as initial-value problems. Results from programs based on each method are presented showing the power and limitations of the methods and the range of problems solvable. The methods are compared and recommendations are made for choosing between them. Suggestions are made for improving both methods, involving boundary integral techniques. (author)

Novel Method for Sizing Metallic Bottom Crack Depth Using Multi-frequency Alternating Current Potential Drop Technique

Directory of Open Access Journals (Sweden)

Li Yuting

2015-10-01

Full Text Available Potential drop techniques are of two types: the direct current potential drop (DCPD technique and alternating current potential drop (ACPD technique, and both of them are used in nondestructive testing. ACPD, as a kind of valid method in sizing metal cracks, has been applied to evaluate metal structures. However, our review of most available approaches revealed that some improvements can be done in measuring depth of metal bottom crack by means of ACPD, such as accuracy and sensitivity of shallow crack. This paper studied a novel method which utilized the slope of voltage ratio-frequency curve to solve bottom crack depth by using a simple mathematic equation based on finite element analysis. It is found that voltage ratio varies linearly with frequency in the range of 5-15 Hz; this range is slightly higher than the equivalent frequency and lower than semi-permeable frequency. Simulation and experiment show that the novel method can measure the bottom crack depth accurately.

Novel Method for Sizing Metallic Bottom Crack Depth Using Multi-frequency Alternating Current Potential Drop Technique

Science.gov (United States)

Li, Yuting; Gan, Fangji; Wan, Zhengjun; Liao, Junbi; Li, Wenqiang

2015-10-01

Potential drop techniques are of two types: the direct current potential drop (DCPD) technique and alternating current potential drop (ACPD) technique, and both of them are used in nondestructive testing. ACPD, as a kind of valid method in sizing metal cracks, has been applied to evaluate metal structures. However, our review of most available approaches revealed that some improvements can be done in measuring depth of metal bottom crack by means of ACPD, such as accuracy and sensitivity of shallow crack. This paper studied a novel method which utilized the slope of voltage ratio-frequency curve to solve bottom crack depth by using a simple mathematic equation based on finite element analysis. It is found that voltage ratio varies linearly with frequency in the range of 5-15 Hz; this range is slightly higher than the equivalent frequency and lower than semi-permeable frequency. Simulation and experiment show that the novel method can measure the bottom crack depth accurately.

Innovations in electrophoretic deposition: Alternating current and pulsed direct current methods

International Nuclear Information System (INIS)

Chávez-Valdez, Alejandra; Boccaccini, Aldo R.

2012-01-01

This review summarizes emerging developments in the field of alternating current (AC) and pulsed direct current (DC) electrophoretic deposition (EPD) in aqueous or organic media. Numerous applications of AC-EPD are discussed including two major groups of investigations: (i) AC-EPD to suppress water hydrolysis at high voltages in inorganic (ceramic) coatings and (ii) AC-EPD for deposition of biological entities. The deposition, purification and manipulation of carbon nanotubes and nanoparticles by AC-EPD to form specific arrays, for development of sensors and other electronic devices and the application of AC-EPD as method for separation of particles according to their shape or size are also presented. Other applications reviewed relate to the fabrication by AC-EPD of toxic gas sensors from oxides and superconducting layers. The main materials being examined by AC-EPD are inorganic, including carbon nanotubes, TiO 2 nanoparticles, Al 2 O 3 , Si, SnO 2 , ZnO and WO 3 and biological entities, e.g. bacteria cells. For pulsed EPD, the applications reviewed are divided in pulsed current and pulsed voltage EPD. Among the applications of pulsed EPD, the formation of thick films from aqueous suspensions without water decomposition, the fabrication of multilayer and composite materials and the size-selective deposition of ceramic nanoparticles are the most important investigated to date, based on the quality of the coatings and deposits obtained and their relevance for applications.

Investigating the computer analysis of eddy current NDT data

International Nuclear Information System (INIS)

Brown, R.L.

1979-01-01

The objective of this activity was to investigate and develop techniques for computer analysis of eddy current nondestructive testing (NDT) data. A single frequency commercial eddy current tester and a precision mechanical scanner were interfaced with a PDP-11/34 computer to obtain and analyze eddy current data from samples of 316 stainless steel tubing containing known discontinuities. Among the data analysis techniques investigated were: correlation, Fast Fourier Transforms (FFT), clustering, and Adaptive Learning Networks (ALN). The results were considered encouraging. ALN, for example, correctly identified 88% of the defects and non-defects from a group of 153 signal indications

The glenoid track: a review of the clinical relevance, method of calculation and current evidence behind this method

Energy Technology Data Exchange (ETDEWEB)

Younan, Yara; Wong, Philip K.; Umpierrez, Monica; Gonzalez, Felix; Singer, Adam Daniel [Emory University Hospital, Department of Radiology and Imaging Sciences, Section of Musculoskeletal Imaging, Atlanta, GA (United States); Karas, Spero [Emory University Hospital, Department of Orthopedic Surgery, Atlanta, GA (United States); Jose, Jean [University of Miami, Department of Radiology, Miami, FL (United States)

2017-12-15

In the setting of bipolar bone injury, orthopedic surgeons are currently making use of the glenoid track method to guide surgical management. Using preoperative CT or MR imaging, this method allows the identification of patients who are more likely to fail a primary capsuloligamentous Bankart repair. As the glenoid track method becomes increasingly used in preoperative planning, it is important for the radiologist to become familiar with its concept and method of calculation. This review article aims to concisely summarize the current literature and the clinical implications of the glenoid track method. (orig.)

Method for critical current testing

International Nuclear Information System (INIS)

Siddall, M.B.; Smathers, D.B.

1989-01-01

Superconducting critical current testing software was developed with four important features not feasible with analog test equipment. First, quasi-steady-state sample current conditions are achieved by incrementing sample current, followed by holding some milliseconds until the transient voltage decays before voltage sampling. Then the self-field correction from a helically wound sample is computed and subtracted from each sampled field reading. A copper wire inductively wound shunt which is used for quench protection has a constant measured resistance from which the shunt leakage current is computed and subtracted from the sample current by measuring the shunt voltage after each sample current reading. Finally, the critical current is recomputed from a least squares curve fit to the power law: E=A*In when the correlation coefficient for the fit is high enough to ensure a better result than the raw datum. Comparison with NBS Standard Reference Material (NbTi) and current round robin Nb/sub 3/Sn testing is examined

In situ visualization and data analysis for turbidity currents simulation

Science.gov (United States)

Camata, Jose J.; Silva, Vítor; Valduriez, Patrick; Mattoso, Marta; Coutinho, Alvaro L. G. A.

2018-01-01

Turbidity currents are underflows responsible for sediment deposits that generate geological formations of interest for the oil and gas industry. LibMesh-sedimentation is an application built upon the libMesh library to simulate turbidity currents. In this work, we present the integration of libMesh-sedimentation with in situ visualization and in transit data analysis tools. DfAnalyzer is a solution based on provenance data to extract and relate strategic simulation data in transit from multiple data for online queries. We integrate libMesh-sedimentation and ParaView Catalyst to perform in situ data analysis and visualization. We present a parallel performance analysis for two turbidity currents simulations showing that the overhead for both in situ visualization and in transit data analysis is negligible. We show that our tools enable monitoring the sediments appearance at runtime and steer the simulation based on the solver convergence and visual information on the sediment deposits, thus enhancing the analytical power of turbidity currents simulations.

Current role of liquid chromatography coupled to mass spectrometry in clinical toxicology screening methods.

Science.gov (United States)

Viette, Véronique; Fathi, Marc; Rudaz, Serge; Hochstrasser, Denis; Veuthey, Jean-Luc

2011-07-01

Abstract Toxicological screening is the analysis of a biological specimen to detect and identify compounds in patients admitted to the hospital with acute intoxication of unknown origin. The screening of a wide range of toxicologically relevant compounds in biological samples is a serious challenge for clinical laboratories. The high selectivity and sensitivity of liquid chromatography coupled to mass spectrometry or tandem mass spectrometry technology provides an attractive alternative to the current methods. For these reasons, an increasing number of applications for multi-target screening or general screening of unknown compounds in biological matrices are being published. This paper is an overview of sample clean-up, chromatographic separation and mass spectrometry detection procedures which can be combined to obtain screening methods adapted to the constraints and needs of various laboratories, and none specifically in clinical toxicology. Currently the techniques are in the hands of specialists, principally in academic institutes. However, the evolution in technology should allow application of the techniques as a tool in toxicology laboratories and thus more widespread exploitation of their potential.

A Steel Ball Surface Quality Inspection Method Based on a Circumferential Eddy Current Array Sensor

Directory of Open Access Journals (Sweden)

Huayu Zhang

2017-07-01

Full Text Available To efficiently inspect surface defects on steel ball bearings, a new method based on a circumferential eddy current array (CECA sensor was proposed here. The best probe configuration, in terms of the coil quality factor (Q-factor, magnetic field intensity, and induced eddy current density on the surface of a sample steel ball, was determined using 3-, 4-, 5-, and 6-coil probes, for analysis and comparison. The optimal lift-off from the measured steel ball, the number of probe coils, and the frequency of excitation current suitable for steel ball inspection were obtained. Using the resulting CECA sensor to inspect 46,126 steel balls showed a miss rate of ~0.02%. The sensor was inspected for surface defects as small as 0.05 mm in width and 0.1 mm in depth.

Method for analysis the complex grounding cables system

International Nuclear Information System (INIS)

Ackovski, R.; Acevski, N.

2002-01-01

A new iterative method for the analysis of the performances of the complex grounding systems (GS) in underground cable power networks with coated and/or uncoated metal sheathed cables is proposed in this paper. The analyzed grounding system consists of the grounding grid of a high voltage (HV) supplying transformer station (TS), middle voltage/low voltage (MV/LV) consumer TSs and arbitrary number of power cables, connecting them. The derived method takes into consideration the drops of voltage in the cable sheets and the mutual influence among all earthing electrodes, due to the resistive coupling through the soil. By means of the presented method it is possible to calculate the main grounding system performances, such as earth electrode potentials under short circuit fault to ground conditions, earth fault current distribution in the whole complex grounding system, step and touch voltages in the nearness of the earthing electrodes dissipating the fault current in the earth, impedances (resistances) to ground of all possible fault locations, apparent shield impedances to ground of all power cables, e.t.c. The proposed method is based on the admittance summation method [1] and is appropriately extended, so that it takes into account resistive coupling between the elements that the GS. (Author)

Earth analysis methods, subsurface feature detection methods, earth analysis devices, and articles of manufacture

Science.gov (United States)

West, Phillip B [Idaho Falls, ID; Novascone, Stephen R [Idaho Falls, ID; Wright, Jerry P [Idaho Falls, ID

2011-09-27

Earth analysis methods, subsurface feature detection methods, earth analysis devices, and articles of manufacture are described. According to one embodiment, an earth analysis method includes engaging a device with the earth, analyzing the earth in a single substantially lineal direction using the device during the engaging, and providing information regarding a subsurface feature of the earth using the analysis.

Verification of the Viability of Equipotential Switching Direct Current Potential Drop Method for Piping Wall Loss Monitoring with Signal Sensitivity Analysis

International Nuclear Information System (INIS)

Ryu, Kyung Ha; Hwang, Il Soon; Kim, Ji Hyun

2008-01-01

Flow accelerated corrosion (FAC) phenomenon of low alloy carbon steels in nuclear power plant has been known as one of major degradation mechanisms. It has a potential to cause nuclear pipe rupture accident which may directly impact on the plant reliability and safety. Recently, the equipotential switching direct current potential drop (ES-DCPD) method has been developed, by the present authors, as a method to monitor wall loss in a piping. This method can rapidly monitor the thinning of piping, utilizing either the wide range monitoring (WiRM) or the narrow range monitoring (NaRM) technique. WiRM is a method to monitor wide range of straight piping, whereas NaRM focuses significantly on a narrow range such as an elbow. WiRM and NaRM can improve the reliability of the current FAC screening method that is based on computer modeling on fluid flow conditions. In this paper, the measurements by ES-DCPD are performed with signal sensitivity analyses in the laboratory environment for extended period and showed the viability of ES-DCPD for real plant applications.

Mixed arrays - problems with current methods and rules

International Nuclear Information System (INIS)

Mennerdahl, D.

1987-01-01

Simplified methods are used to control the criticality safety of mixed arrays (non-identical units) in storage or in transport. The basis for these methods is that the analyses of arrays of identical units are sufficient for drawing proper conclusions on mixed arrays. In a recent study of the rules for transport, two general flaws in such methods have been identified. One flaw is caused by increased neutron return rate to the central part of the array. The other flaw is caused by increased neutron coupling between two or more fissile units in an array. In both cases, replacement of fissile units with other units, which appear to be less reactive, can lead to criticality. This paper shows that the two flaws are common in also in current methods used for storage of fissile materials. (author)

Method of controlling illumination device based on current-voltage model

DEFF Research Database (Denmark)

2013-01-01

The present invention relates to an illumination device comprising a number of LEDs, means for receiving an input signal, means for generating an activation signal for at least one of the LEDs based on the input signal. The illumination device comprises further means for obtaining the voltage...... and the colorimetric properties of said light emitted by LED. The present invention relates also to a method of controlling and a meted of calibrating such illumination device....... across and current through the LED and the means for generating the activation signal is adapted to generate the activating signal based on the voltage, the current and a current- voltage model related to LED. The current-voltage model defines a relationship between the current, the voltage...

Method and apparatus to trigger superconductors in current limiting devices

Science.gov (United States)

Yuan, Xing; Hazelton, Drew Willard; Walker, Michael Stephen

2004-10-26

A method and apparatus for magnetically triggering a superconductor in a superconducting fault current limiter to transition from a superconducting state to a resistive state. The triggering is achieved by employing current-carrying trigger coil or foil on either or both the inner diameter and outer diameter of a superconductor. The current-carrying coil or foil generates a magnetic field with sufficient strength and the superconductor is disposed within essentially uniform magnetic field region. For superconductor in a tubular-configured form, an additional magnetic field can be generated by placing current-carrying wire or foil inside the tube and along the center axial line.

Technique of Critical Current Density Measurement of Bulk Superconductor with Linear Extrapolation Method

International Nuclear Information System (INIS)

Adi, Wisnu Ari; Sukirman, Engkir; Winatapura, Didin S.

2000-01-01

Technique of critical current density measurement (Jc) of HTc bulk ceramic superconductor has been performed by using linear extrapolation with four-point probes method. The measurement of critical current density HTc bulk ceramic superconductor usually causes damage in contact resistance. In order to decrease this damage factor, we introduce extrapolation method. The extrapolating data show that the critical current density Jc for YBCO (123) and BSCCO (2212) at 77 K are 10,85(6) Amp.cm - 2 and 14,46(6) Amp.cm - 2, respectively. This technique is easier, simpler, and the use of the current flow is low, so it will not damage the contact resistance of the sample. We expect that the method can give a better solution for bulk superconductor application. Key words. : superconductor, critical temperature, and critical current density

A comparative study: the impact of different lipid extraction methods on current microalgal lipid research

Science.gov (United States)

2014-01-01

Microalgae cells have the potential to rapidly accumulate lipids, such as triacylglycerides that contain fatty acids important for high value fatty acids (e.g., EPA and DHA) and/or biodiesel production. However, lipid extraction methods for microalgae cells are not well established, and there is currently no standard extraction method for the determination of the fatty acid content of microalgae. This has caused a few problems in microlagal biofuel research due to the bias derived from different extraction methods. Therefore, this study used several extraction methods for fatty acid analysis on marine microalga Tetraselmis sp. M8, aiming to assess the potential impact of different extractions on current microalgal lipid research. These methods included classical Bligh & Dyer lipid extraction, two other chemical extractions using different solvents and sonication, direct saponification and supercritical CO2 extraction. Soxhlet-based extraction was used to weigh out the importance of solvent polarity in the algal oil extraction. Coupled with GC/MS, a Thermogravimetric Analyser was used to improve the quantification of microalgal lipid extractions. Among these extractions, significant differences were observed in both, extract yield and fatty acid composition. The supercritical extraction technique stood out most for effective extraction of microalgal lipids, especially for long chain unsaturated fatty acids. The results highlight the necessity for comparative analyses of microalgae fatty acids and careful choice and validation of analytical methodology in microalgal lipid research. PMID:24456581

Method to predetermine current/power flow change in a dc grid

DEFF Research Database (Denmark)

2017-01-01

occurs at one of the AC/DC converters; establishing a generalized droop feedback gain matrix G; controlling current/power flow within DC grid towards predefined setpoints, by use of control law. The invention presents an analytical approach to derive the generalized feedback gain allowing......The invention relates to a method for controlling current/power flow within a power transmission system, comprising two or more interconnected converter stations. The method comprises the steps of: providing a DC admittance matrix given from the DC grid; providing a current distribution matrix...... for a number of, such as for all possible AC/DC converter outages; providing a DC bus voltage vector for the DC grid; the DC bus voltage vector being a vector containing the values of the voltage change at the AC/DC converters, measured at the AC/DC converters, before, during and after a forced current change...

DETERMINATION OF HYDRAULIC TURBINE EFFICIENCY BY MEANS OF THE CURRENT METER METHOD

Directory of Open Access Journals (Sweden)

PURECE C.

2016-12-01

Full Text Available The paper presents methodology used for determining the efficiency of a low head Kaplan hydraulic turbine with short converging intake. The measurement method used was the current meters method, the only measurement method recommended by the IEC 41standard for flow measurement in this case. The paper also presents the methodology used for measuring the flow by means of the current meters method and the various procedures for calculating the flow. In the last part the paper presents the flow measurements carried out on the Fughiu HPP hydraulic turbines for determining the actual operating efficiency.

Transient analysis for alternating over-current characteristics of HTSC power transmission cable

Science.gov (United States)

Lim, S. H.; Hwang, S. D.

2006-10-01

In this paper, the transient analysis for the alternating over-current distribution in case that the over-current was applied for a high-TC superconducting (HTSC) power transmission cable was performed. The transient analysis for the alternating over-current characteristics of HTSC power transmission cable with multi-layer is required to estimate the redistribution of the over-current between its conducting layers and to protect the cable system from the over-current in case that the quench in one or two layers of the HTSC power cable happens. For its transient analysis, the resistance generation of the conducting layers for the alternating over-current was reflected on its equivalent circuit, based on the resistance equation obtained by applying discrete Fourier transform (DFT) for the voltage and the current waveforms of the HTSC tape, which comprises each layer of the HTSC power transmission cable. It was confirmed through the numerical analysis on its equivalent circuit that after the current redistribution from the outermost layer into the inner layers first happened, the fast current redistribution between the inner layers developed as the amplitude of the alternating over-current increased.

Current Status of Mycotoxin Analysis: A Critical Review.

Science.gov (United States)

Shephard, Gordon S

2016-07-01

It is over 50 years since the discovery of aflatoxins focused the attention of food safety specialists on fungal toxins in the feed and food supply. Since then, analysis of this important group of natural contaminants has advanced in parallel with general developments in analytical science, and current MS methods are capable of simultaneously analyzing hundreds of compounds, including mycotoxins, pesticides, and drugs. This profusion of data may advance our understanding of human exposure, yet constitutes an interpretive challenge to toxicologists and food safety regulators. Despite these advances in analytical science, the basic problem of the extreme heterogeneity of mycotoxin contamination, although now well understood, cannot be circumvented. The real health challenges posed by mycotoxin exposure occur in the developing world, especially among small-scale and subsistence farmers. Addressing these problems requires innovative approaches in which analytical science must also play a role in providing suitable out-of-laboratory analytical techniques.

Probabilistic safety analysis : a new nuclear power plants licensing method

International Nuclear Information System (INIS)

Oliveira, L.F.S. de.

1982-04-01

After a brief retrospect of the application of Probabilistic Safety Analysis in the nuclear field, the basic differences between the deterministic licensing method, currently in use, and the probabilistic method are explained. Next, the two main proposals (by the AIF and the ACRS) concerning the establishment of the so-called quantitative safety goals (or simply 'safety goals') are separately presented and afterwards compared in their most fundamental aspects. Finally, some recent applications and future possibilities are discussed. (Author) [pt

A Review of Current Methods for Analysis of Mycotoxins in Herbal Medicines

Science.gov (United States)

Zhang, Lei; Dou, Xiao-Wen; Zhang, Cheng; Logrieco, Antonio F.; Yang, Mei-Hua

2018-01-01

The presence of mycotoxins in herbal medicines is an established problem throughout the entire world. The sensitive and accurate analysis of mycotoxin in complicated matrices (e.g., herbs) typically involves challenging sample pretreatment procedures and an efficient detection instrument. However, although numerous reviews have been published regarding the occurrence of mycotoxins in herbal medicines, few of them provided a detailed summary of related analytical methods for mycotoxin determination. This review focuses on analytical techniques including sampling, extraction, cleanup, and detection for mycotoxin determination in herbal medicines established within the past ten years. Dedicated sections of this article address the significant developments in sample preparation, and highlight the importance of this procedure in the analytical technology. This review also summarizes conventional chromatographic techniques for mycotoxin qualification or quantitation, as well as recent studies regarding the development and application of screening assays such as enzyme-linked immunosorbent assays, lateral flow immunoassays, aptamer-based lateral flow assays, and cytometric bead arrays. The present work provides a good insight regarding the advanced research that has been done and closes with an indication of future demand for the emerging technologies. PMID:29393905

Application of the IPEBS method to dynamic contingency analysis

Energy Technology Data Exchange (ETDEWEB)

Martins, A C.B. [FURNAS, Rio de Janeiro, RJ (Brazil); Pedroso, A S [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)

1994-12-31

Dynamic contingency analysis is certainly a demanding task in the context of dynamic performance evaluation. This paper presents the results of a test for checking the contingency screening capability of the IPEBS method. A brazilian 1100-bus, 112-gen system was used in the test; the ranking of the contingencies based on critical clearing times obtained with IPEBS, was compared with the ranking derived from detailed time-domain simulation. The results of this comparison encourages us to recommended the use of the method in industry applications, in a complementary basis to the current method of time domain simulation. (author) 5 refs., 1 fig., 2 tabs.

An assessment of current methods for stabilising steep cut slopes by ...

African Journals Online (AJOL)

This paper examines the various current methods that are being used throughout South Africa and assesses the merits of such methods. Furthermore, factors that have an overriding influence on the success of a particular method in a certain set of circumstances are analysed. Cost comparisons are produced to assist in ...

Why Map Issues? On Controversy Analysis as a Digital Method.

Science.gov (United States)

Marres, Noortje

2015-09-01

This article takes stock of recent efforts to implement controversy analysis as a digital method in the study of science, technology, and society (STS) and beyond and outlines a distinctive approach to address the problem of digital bias. Digital media technologies exert significant influence on the enactment of controversy in online settings, and this risks undermining the substantive focus of controversy analysis conducted by digital means. To address this problem, I propose a shift in thematic focus from controversy analysis to issue mapping. The article begins by distinguishing between three broad frameworks that currently guide the development of controversy analysis as a digital method, namely, demarcationist, discursive, and empiricist. Each has been adopted in STS, but only the last one offers a digital "move beyond impartiality." I demonstrate this approach by analyzing issues of Internet governance with the aid of the social media platform Twitter.

Plutonium metal exchange program : current status and statistical analysis

Energy Technology Data Exchange (ETDEWEB)

Tandon, L. (Lav); Eglin, J. L. (Judith Lynn); Michalak, S. E. (Sarah E.); Picard, R. R.; Temer, D. J. (Donald J.)

2004-01-01

The Rocky Flats Plutonium (Pu) Metal Sample Exchange program was conducted to insure the quality and intercomparability of measurements such as Pu assay, Pu isotopics, and impurity analyses. The Rocky Flats program was discontinued in 1989 after more than 30 years. In 2001, Los Alamos National Laboratory (LANL) reestablished the Pu Metal Exchange program. In addition to the Atomic Weapons Establishment (AWE) at Aldermaston, six Department of Energy (DOE) facilities Argonne East, Argonne West, Livermore, Los Alamos, New Brunswick Laboratory, and Savannah River are currently participating in the program. Plutonium metal samples are prepared and distributed to the sites for destructive measurements to determine elemental concentration, isotopic abundance, and both metallic and nonmetallic impurity levels. The program provides independent verification of analytical measurement capabilies for each participating facility and allows problems in analytical methods to be identified. The current status of the program will be discussed with emphasis on the unique statistical analysis and modeling of the data developed for the program. The discussion includes the definition of the consensus values for each analyte (in the presence and absence of anomalous values and/or censored values), and interesting features of the data and the results.

Current, voltage and temperature distribution modeling of light-emitting diodes based on electrical and thermal circuit analysis

International Nuclear Information System (INIS)

Yun, J; Shim, J-I; Shin, D-S

2013-01-01

We demonstrate a modeling method based on the three-dimensional electrical and thermal circuit analysis to extract current, voltage and temperature distributions of light-emitting diodes (LEDs). In our model, the electrical circuit analysis is performed first to extract the current and voltage distributions in the LED. Utilizing the result obtained from the electrical circuit analysis as distributed heat sources, the thermal circuit is set up by using the duality between Fourier's law and Ohm's law. From the analysis of the thermal circuit, the temperature distribution at each epitaxial film is successfully obtained. Comparisons of experimental and simulation results are made by employing an InGaN/GaN multiple-quantum-well blue LED. Validity of the electrical circuit analysis is confirmed by comparing the light distribution at the surface. Since the temperature distribution at each epitaxial film cannot be obtained experimentally, the apparent temperature distribution is compared at the surface of the LED chip. Also, experimentally obtained average junction temperature is compared with the value calculated from the modeling, yielding a very good agreement. The analysis method based on the circuit modeling has an advantage of taking distributed heat sources as inputs, which is essential for high-power devices with significant self-heating. (paper)

Magnetic Field Equivalent Current Analysis-Based Radial Force Control for Bearingless Permanent Magnet Synchronous Motors

Directory of Open Access Journals (Sweden)

Huangqiu Zhu

2015-05-01

Full Text Available Bearingless permanent magnet synchronous motors (BPMSMs, with all advantages of permanent magnet motors (PMSMs and magnetic bearings, have become an important research direction in the bearingless motor field. To realize a stable suspension for the BPMSM, accurate decoupling control between the electromagnetic torque and radial suspension force is indispensable. In this paper, a concise and reliable analysis method based on a magnetic field equivalent current is presented. By this analysis method, the operation principle is analyzed theoretically, and the necessary conditions to produce a stable radial suspension force are confirmed. In addition, mathematical models of the torque and radial suspension force are established which is verified by the finite element analysis (FEA software ANSYS. Finally, an experimental prototype of a 2-4 poles surface-mounted BPMSM is tested with the customized control strategy. The simulation and experimental results have shown that the motor has good rotation and suspension performance, and validated the accuracy of the proposed analysis method and the feasibility of the control strategy.

Harmonic current layer method for the design of superconducting quadrupole magnetic field

International Nuclear Information System (INIS)

Zizek, F.

1977-01-01

The magnetic field of a superconducting quadrupole is investigated by the method of harmonic current layers of cylindrical shape. The superconducting winding is replaced by a system of thin current layers with a harmonically distributed density of the surface current along the circumference. The effect of the outer ferromagnetic circuit with an arbitrary constant permeability over the cross section is replaced analogically. The resultant magnetic field is then given by the superposition of the contributions from the individual current layers. The calculation method can be modified for the selection of the geometry of the winding for the latter to meet the demand for the high homogeneity of the gradient of magnetic induction in the working space of the superconducting quadrupole. (author)

Bearing failure detection of micro wind turbine via power spectral density analysis for stator current signals spectrum

Science.gov (United States)

Mahmood, Faleh H.; Kadhim, Hussein T.; Resen, Ali K.; Shaban, Auday H.

2018-05-01

The failure such as air gap weirdness, rubbing, and scrapping between stator and rotor generator arise unavoidably and may cause extremely terrible results for a wind turbine. Therefore, we should pay more attention to detect and identify its cause-bearing failure in wind turbine to improve the operational reliability. The current paper tends to use of power spectral density analysis method of detecting internal race and external race bearing failure in micro wind turbine by estimation stator current signal of the generator. The failure detector method shows that it is well suited and effective for bearing failure detection.

Economic analysis of alternative LLW disposal methods

International Nuclear Information System (INIS)

Foutes, C.E.; Queenan, C.J. III

1987-01-01

The Environmental Protection Agency (EPA) has evaluated the costs and benefits of alternative disposal technologies as part of its program to develop generally applicable environmental standards for the land disposal of low-level radioactive waste (LLW). Costs, population health effects and Critical Population Group (CPG) exposures resulting from alternative waste treatment and disposal methods were evaluated both in absolute terms and also relative to a base case (current practice). Incremental costs of the standard included costs for packaging, processing, transportation, and burial of waste. Benefits are defined in terms of reductions in the general population health risk (expected fatal cancers and genetic effects) evaluated over 10,000 years. A cost-effectiveness ratio, defined as the incremental cost per avoided health effect, was calculated for each alternative standard. The cost-effectiveness analysis took into account a number of waste streams, hydrogeologic and climatic region settings, and waste treatment and disposal methods. This paper describes the alternatives considered and preliminary results of the cost-effectiveness analysis. 15 references, 7 figures, 3 tables

Developing a Self-Report-Based Sequential Analysis Method for Educational Technology Systems: A Process-Based Usability Evaluation

Science.gov (United States)

Lin, Yi-Chun; Hsieh, Ya-Hui; Hou, Huei-Tse

2015-01-01

The development of a usability evaluation method for educational systems or applications, called the self-report-based sequential analysis, is described herein. The method aims to extend the current practice by proposing self-report-based sequential analysis as a new usability method, which integrates the advantages of self-report in survey…

Thermal studies of a superconducting current limiter using Monte-Carlo method

International Nuclear Information System (INIS)

Leveque, J.; Rezzoug, A.

1999-01-01

Considering the increase of the fault current level in electrical network, the current limiters become very interesting. The superconducting limiters are based on the quasi-instantaneous intrinsic transition from superconducting state to normal resistive one. Without detection of default or given order, they reduce the constraints supported by electrical installations above the fault. To avoid the destruction of the superconducting coil, the temperature must not exceed a certain value. Therefore the design of a superconducting coil needs the simultaneous resolution of an electrical equation and a thermal one. This papers deals with a resolution of this coupled problem by the method of Monte-Carlo. This method allows us to calculate the evolution of the resistance of the coil as well as the current of limitation. Experimental results are compared with theoretical ones. (orig.)

Methods for the Determination of Currents and Fields in Steady Two-Dimensional MHD Flow With Tensor Conductivity

International Nuclear Information System (INIS)

Witalis, E.A.

1965-12-01

Rigorous derivations are given of the basic equations and methods available for the analysis of transverse MHD flow when Hall currents are not suppressed. The gas flow is taken to be incompressible and viscous with uniform tensor conductivity and arbitrary magnetic Reynold's number. The magnetic field is perpendicular to the flow and has variable strength. Analytical solutions can be obtained either in terms of the induced magnetic field or from two types of electric potential. The relevant set of suitable simplifications, restrictive conditions and boundary value considerations for each method is given

Methods for the Determination of Currents and Fields in Steady Two-Dimensional MHD Flow With Tensor Conductivity

Energy Technology Data Exchange (ETDEWEB)

Witalis, E A

1965-12-15

Rigorous derivations are given of the basic equations and methods available for the analysis of transverse MHD flow when Hall currents are not suppressed. The gas flow is taken to be incompressible and viscous with uniform tensor conductivity and arbitrary magnetic Reynold's number. The magnetic field is perpendicular to the flow and has variable strength. Analytical solutions can be obtained either in terms of the induced magnetic field or from two types of electric potential. The relevant set of suitable simplifications, restrictive conditions and boundary value considerations for each method is given.

Analysis and design of grid-current-feedback active damping for LCL resonance in grid-connected voltage source converters

DEFF Research Database (Denmark)

Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang

2014-01-01

This paper investigates the active damping of LCL-filter resonance within single-loop grid current control of grid-connected voltage source converters. First, the basic analysis in the continuous s-domain reveals that the grid-current-feedback active damping forms a virtual impedance across...... in a digital control system. The instability induced by the negative virtual resistance, which is commonly experienced in the feedback-type active damping, can thus be avoided. A systematic design method of the highpass filter is also proposed by the help of root locus analysis in the discrete z-domain. Lastly...

Methods in carbon K-edge NEXAFS: Experiment and analysis

International Nuclear Information System (INIS)

Watts, B.; Thomsen, L.; Dastoor, P.C.

2006-01-01

Near-edge X-ray absorption spectroscopy (NEXAFS) is widely used to probe the chemistry and structure of surface layers. Moreover, using ultra-high brilliance polarised synchrotron light sources, it is possible to determine the molecular alignment of ultra-thin surface films. However, the quantitative analysis of NEXAFS data is complicated by many experimental factors and, historically, the essential methods of calibration, normalisation and artefact removal are presented in the literature in a somewhat fragmented manner, thus hindering their integrated implementation as well as their further development. This paper outlines a unified, systematic approach to the collection and quantitative analysis of NEXAFS data with a particular focus upon carbon K-edge spectra. As a consequence, we show that current methods neglect several important aspects of the data analysis process, which we address with a combination of novel and adapted techniques. We discuss multiple approaches in solving the issues commonly encountered in the analysis of NEXAFS data, revealing the inherent assumptions of each approach and providing guidelines for assessing their appropriateness in a broad range of experimental situations

Study of nasal swipe analysis methods at Los Alamos National Laboratory

International Nuclear Information System (INIS)

Metcalf, R.A.

1996-01-01

The Health Physics Analysis Laboratory (HPAL) performs around 30,000 nasal swipe analyses for transuranic nuclides each year in support of worker health and safety at the Los Alamos National Laboratory (LANL). The analysis method used employs cotton swabs swiped inside a nostril and liquid scintillation analyses of the swabs. The technical basis of this method was developed at LANL and has been in use for over 10 years. Recently, questions regarding the usefulness of a non-homogeneous mixture in liquid scintillation analyses have created a need for re-evaluation of the method. A study of the validity of the method shows it provides reliable, stable, and useful data as an indicator of personnel contamination. The study has also provided insight into the underlying process which occurs to allow the analysis. Further review of this process has shown that similar results can be obtained with different sample matrices, using less material than the current analysis method. This reduction can save HPAL the cost of materials as well as greatly reduce the waste created. Radionuclides of concern include Am-241, Pu-239, and Pu-238

Development of spectral history methods for pin-by-pin core analysis method using three-dimensional direct response matrix

International Nuclear Information System (INIS)

Mitsuyasu, T.; Ishii, K.; Hino, T.; Aoyama, M.

2009-01-01

Spectral history methods for pin-by-pin core analysis method using the three-dimensional direct response matrix have been developed. The direct response matrix is formalized by four sub-response matrices in order to respond to a core eigenvalue k and thus can be recomposed at each outer iteration in the core analysis. For core analysis, it is necessary to take into account the burn-up effect related to spectral history. One of the methods is to evaluate the nodal burn-up spectrum obtained using the out-going neutron current. The other is to correct the fuel rod neutron production rates obtained the pin-by-pin correction. These spectral history methods were tested in a heterogeneous system. The test results show that the neutron multiplication factor error can be reduced by half during burn-up, the nodal neutron production rates errors can be reduced by 30% or more. The root-mean-square differences between the relative fuel rod neutron production rate distributions can be reduced within 1.1% error. This means that these methods can accurately reflect the effects of intra- and inter-assembly heterogeneities during burn-up and can be used for core analysis. Core analysis with the DRM method was carried out for an ABWR quarter core and it was found that both thermal power and coolant-flow distributions were smoothly converged. (authors)

Charged Current Quasielastic Analysis from MINERνA

Energy Technology Data Exchange (ETDEWEB)

Ghosh, Anushree [Rio de Janeiro, CBPF

2015-08-01

The MINERνA detector situated in Fermilab, is designed to make precision cross-section measurements for scattering processes on various nuclei. In this proceeding, the results of the charged current quasi-elastic (CCQE) analysis using lepton kinematics and with proton kinematics have been presented. Comparison of these with theoretical models suggested that further studies are required to include the additional nuclear effects in the current simulations. The first direct measurement of electron-neutrino quasielastic-like scattering in the few-GeV region of incident neutrino energy has also been presented. All three analyses, discussed here, are carried out on hydrocarbon target.

Short-Circuit Current Analysis for DFIG Wind Farm Considering the Action of a Crowbar

Directory of Open Access Journals (Sweden)

Yan Hong Yuan

2018-02-01

Full Text Available With the increasing capacity of wind farms integrated into the power grid, the short-circuit current analysis for wind farms becomes more and more important. Since the wind turbine is usually integrated into the power grid via power electronic devices, the “crowbar” is installed in the wind turbine to protect the power electronic devices and to improve the fault ride through capability. The impact of the crowbar has to be considered during the short-circuit current analysis for the wind farm. In order to fully analyze the short-circuit current characteristics of a wind farm, the short-circuit currents for a doubly-fed induction generator (DFIG wind turbine under symmetrical and asymmetrical faults considering the crowbar action characteristic are derived firstly. Then the action situation of the crowbar of a DFIG wind turbine is studied and the action area curve is obtained. Taking the crowbar action, or not, as the grouping criterion, wind turbines in the wind farm are divided into two groups, and the wind farm is aggregated into two equivalent wind turbines. Using the equivalent model, the short-circuit current of a wind farm can be calculated accurately. Finally, simulations are performed in MATLAB/Simulink which is the commercial math software produced by the MathWorks company in Natick, Massachusetts, the United States to verify the proposed short-circuit current calculation method for the DFIG wind farm.

Current use of contraceptive method among women in a middle-income developing country

Directory of Open Access Journals (Sweden)

Paul A Bourne

2010-06-01

Full Text Available Paul A Bourne1, Christopher AD Charles2,3, Tazhmoye V Crawford4, Maureen D Kerr-Campbell5, Cynthia G Francis1, Neva South-Bourne11Department of Community Health and Psychiatry, Faculty of Medical Sciences, The University of the West Indies, Mona, Kingston, Jamaica; 2King Graduate School, Monroe College, Bronx, New York, USA; 3Center for Victim Support, Harlem Hospital Center, New York; 4Basic Medical Sciences, Faculty of Medical Sciences, 5Systems Development Unit, Main Library, Faculty of Humanities and Education, The University of the West Indies, Mona, JamaicaBackground: Jamaica is a mid-range income developing country with an increasing population and public resource constraints. Therefore, reproductive health issues are of critical importance in Jamaica.Aim: We examined the use of contraceptives among women and the factors that influence these women to use contraceptives.Materials and method: In the current study we utilized the secondary dataset for the Reproductive Health Survey, conducted by the National Family Planning Board. The investigation was carried out with a stratified random sample of 7168 women aged between 15 and 49. The measures included demographic variables, method of contraception used, being in a relationship, number of partners, pregnancy status, and sexual activity status, along with other variables.Results: The majority of participants used some method of contraception (64%. The most popular method of contraception was a condom (32%. Results of a multivariate analysis suggests that the explanatory variables for the method of contraception used are age (OR = 0.98, 95% CI: 0.98–0.99, social class (OR = 0.83, 95% CI: 0.73–0.95, being in a relationship (OR = 3.35, 95% CI: 2.80–4.02, the rural–urban dichotomy (OR = 1.16, 95% CI: 1.02–1.32, being currently pregnant (OR = 0.01, 95% CI: 0.00–0.02, currently having sex (OR = 2.29, 95% CI: 1.95–2.70, number of partners (OR = 1.85, 95% CI: 1.57–2.17, the age at

Analysis of harmonic current interaction in an industrial plant

NARCIS (Netherlands)

Cuk, V.; Cobben, J.F.G.; Kling, W.L.; Timens, R.B.

2011-01-01

An analysis of current transients caused by the operation of a nearby device in an industrial plant is presented in the paper. The source of current transients in the factory lighting system was traced to the operation of the nearby six-pulse AC/DC converter. To determine the nature of the

Preliminary analysis of accident in SST-1 current feeder system

International Nuclear Information System (INIS)

Roy, Swati; Kanabar, Deven; Garg, Atul; Singh, Amit; Tanna, Vipul; Prasad, Upendra; Srinivasan, R.

2017-01-01

Steady-state Tokamak-1 (SST-1) has 16 superconducting Toroidal field (TF) and 9 superconducting poloidal field (PF) coils rated for 10kA DC. All the TF are connected in series and are operated in DC condition whereas PF coils are individually operated in pulse mode during SST-1 campaigns. SST-1 current feeder system (CFS) houses 9 pairs of PF current leads and 1 pair of TF current leads. During past SST-1 campaign, there were arcing incidents within SST-1 CFS chamber which caused significant damage to PF superconducting current leads as well as its Helium cooling lines of the current leads. This paper brings out the preliminary analysis of the mentioned arcing incident, possible reasons and its investigation thereby laying out the sequence of events. From this analysis and observations, various measures to avoid such arcing incidents have also been proposed. (author)

Research on Integrated Analysis Method for Equipment and Tactics Based on Intervention Strategy Discussion

Institute of Scientific and Technical Information of China (English)

陈超; 张迎新; 毛赤龙

2012-01-01

As the increase of the complexity of the information warfare,its intervention strategy needs to be designed in an integrated environment.However,the current research always breaks the internal relation between equipment and tactics,and it is difficult to meet the requirements of their integrated analysis.In this paper,the research status quo of the integrated analysis about equipment and tactics is discussed first,some shortages of the current methods are summarized then,and an evolvement mechanism of the integrated analysis for equipment and tactics is given finally.Based on these,a framework of integrated analysis is proposed.This method＇s effectiveness is validated by an example.

Comparative analysis of minor histocompatibility antigens genotyping methods

Directory of Open Access Journals (Sweden)

A. S. Vdovin

2016-01-01

Full Text Available The wide range of techniques could be employed to find mismatches in minor histocompatibility antigens between transplant recipients and their donors. In the current study we compared three genotyping methods based on polymerase chain reaction (PCR for four minor antigens. Three of the tested methods: allele-specific PCR, restriction fragment length polymorphism and real-time PCR with TaqMan probes demonstrated 100% reliability when compared to Sanger sequencing for all of the studied polymorphisms. High resolution melting analysis was unsuitable for genotyping of one of the tested minor antigens (HA-1 as it has linked synonymous polymorphism. Obtained data could be used to select the strategy for large-scale clinical genotyping.

Noise-based tube current reduction method with iterative reconstruction for reduction of radiation exposure in coronary CT angiography

International Nuclear Information System (INIS)

Shen, Junlin; Du, Xiangying; Guo, Daode; Cao, Lizhen; Gao, Yan; Bai, Mei; Li, Pengyu; Liu, Jiabin; Li, Kuncheng

2013-01-01

Purpose: To investigate the potential of noise-based tube current reduction method with iterative reconstruction to reduce radiation exposure while achieving consistent image quality in coronary CT angiography (CCTA). Materials and methods: 294 patients underwent CCTA on a 64-detector row CT equipped with iterative reconstruction. 102 patients with fixed tube current were assigned to Group 1, which was used to establish noise-based tube current modulation formulas, where tube current was modulated by the noise of test bolus image. 192 patients with noise-based tube current were randomly assigned to Group 2 and Group 3. Filtered back projection was applied for Group 2 and iterative reconstruction for Group 3. Qualitative image quality was assessed with a 5 point score. Image noise, signal intensity, volume CT dose index, and dose-length product were measured. Results: The noise-based tube current modulation formulas were established through regression analysis using image noise measurements in Group 1. Image noise was precisely maintained at the target value of 35.00 HU with small interquartile ranges for Group 2 (34.17–35.08 HU) and Group 3 (34.34–35.03 HU), while it was from 28.41 to 36.49 HU for Group 1. All images in the three groups were acceptable for diagnosis. A relative 14% and 41% reduction in effective dose for Group 2 and Group 3 were observed compared with Group 1. Conclusion: Adequate image quality could be maintained at a desired and consistent noise level with overall 14% dose reduction using noise-based tube current reduction method. The use of iterative reconstruction further achieved approximately 40% reduction in effective dose

COMPUTER METHODS OF GENETIC ANALYSIS.

Directory of Open Access Journals (Sweden)

A. L. Osipov

2017-02-01

Full Text Available The basic statistical methods used in conducting the genetic analysis of human traits. We studied by segregation analysis, linkage analysis and allelic associations. Developed software for the implementation of these methods support.

Noncircular plasma shape analysis in long-pulse current drive experiment in TRIAM-1M

International Nuclear Information System (INIS)

Minooka, Mayumi; Kawasaki, Shoji; Jotaki, Eriko; Moriyama, Shin-ichi; Nagao, Akihiro; Nakamura, Kazuo; Hiraki, Naoji; Nakamura, Yukio; Itoh, Satoshi

1991-01-01

Plasma cross section was noncircularized and the plasma shape was analyzed in order to study the characteristics of the plasma in long-pulse current drive experiments in high-field superconducting tokamak TRIAM-1M. Filament approximation method was adopted, since on-line processing by data processing computer is possible. The experiments of the noncircularization were carried out during 30-to 60-sec discharges. As a result, it became clear that D-shape plasma of elongation ratio 1.4 was maintained stably. By the analysis the internal inductance and poloidal beta were assessed, and so informations about the plasma current profile and internal pressure were obtained. (author)

The surface analysis methods

International Nuclear Information System (INIS)

Deville, J.P.

1998-01-01

Nowadays, there are a lot of surfaces analysis methods, each having its specificity, its qualities, its constraints (for instance vacuum) and its limits. Expensive in time and in investment, these methods have to be used deliberately. This article appeals to non specialists. It gives some elements of choice according to the studied information, the sensitivity, the use constraints or the answer to a precise question. After having recalled the fundamental principles which govern these analysis methods, based on the interaction between radiations (ultraviolet, X) or particles (ions, electrons) with matter, two methods will be more particularly described: the Auger electron spectroscopy (AES) and x-rays photoemission spectroscopy (ESCA or XPS). Indeed, they are the most widespread methods in laboratories, the easier for use and probably the most productive for the analysis of surface of industrial materials or samples submitted to treatments in aggressive media. (O.M.)

STOCHASTIC METHODS IN RISK ANALYSIS

Directory of Open Access Journals (Sweden)

Vladimíra OSADSKÁ

2017-06-01

Full Text Available In this paper, we review basic stochastic methods which can be used to extend state-of-the-art deterministic analytical methods for risk analysis. We can conclude that the standard deterministic analytical methods highly depend on the practical experience and knowledge of the evaluator and therefore, the stochastic methods should be introduced. The new risk analysis methods should consider the uncertainties in input values. We present how large is the impact on the results of the analysis solving practical example of FMECA with uncertainties modelled using Monte Carlo sampling.

Evaluation of methods for seismic analysis of nuclear fuel reprocessing plants, part 1

International Nuclear Information System (INIS)

Tokarz, F.J.; Murray, R.C.; Arthur, D.F.; Feng, W.W.; Wight, L.H.; Zaslawsky, M.

1975-01-01

Currently, no guidelines exist for choosing methods of structural analysis to evaluate the seismic hazard of nuclear fuel reprocessing plants. This study examines available methods and their applicability to fuel reprocessing plant structures. The results of this study should provide a basis for establishing guidelines recommending methods of seismic analysis for evaluating future fuel reprocessing plants. The approach taken is: (1) to identify critical plant structures and place them in four categories (structures at or near grade; deeply embedded structures; fully buried structures; equipment/vessels/attachments/piping), (2) to select a representative structure in each of the first three categories and perform static and dynamic analysis on each, and (3) to evaluate and recommend method(s) of analysis for structures within each category. The Barnwell Nuclear Fuel Plant is selected as representative of future commercial reprocessing plants. The effect of site characteristics on the structural response is also examined. The response spectra method of analysis combined with the finite element model for each category is recommended. For structures founded near or at grade, the lumped mass model could also be used. If a time history response is required, a time-history analysis is necessary. (U.S.)

Spatial-Temporal Variations of Turbidity and Ocean Current Velocity of the Ariake Sea Area, Kyushu, Japan Through Regression Analysis with Remote Sensing Satellite Data

OpenAIRE

Yuichi Sarusawa; Kohei Arai

2013-01-01

Regression analysis based method for turbidity and ocean current velocity estimation with remote sensing satellite data is proposed. Through regressive analysis with MODIS data and measured data of turbidity and ocean current velocity, regressive equation which allows estimation of turbidity and ocean current velocity is obtained. With the regressive equation as well as long term MODIS data, turbidity and ocean current velocity trends in Ariake Sea area are clarified. It is also confirmed tha...

Analysis of Electric Vehicle DC High Current Conversion Technology

Science.gov (United States)

Yang, Jing; Bai, Jing-fen; Lin, Fan-tao; Lu, Da

2017-05-01

Based on the background of electric vehicles, it is elaborated the necessity about electric energy accurate metering of electric vehicle power batteries, and it is analyzed about the charging and discharging characteristics of power batteries. It is needed a DC large current converter to realize accurate calibration of power batteries electric energy metering. Several kinds of measuring methods are analyzed based on shunts and magnetic induction principle in detail. It is put forward power batteries charge and discharge calibration system principle, and it is simulated and analyzed ripple waves containing rate and harmonic waves containing rate of power batteries AC side and DC side. It is put forward suitable DC large current measurement methods of power batteries by comparing different measurement principles and it is looked forward the DC large current measurement techniques.

EDDYTRAN program system for eddy current, electromagnetic force and structural analysis

International Nuclear Information System (INIS)

Kameari, A.; Nikura, S.

1983-01-01

A computer program system (EDDYTRAN), which is applicable to torus structures of magnetic fusion devices, has been developed to calculate the eddy current, electromagnetic force and structural analysis. The program system is designed to perform the following functions sequentially: 1) generation of model mesh and other data such as electromagnetic and mechanical properties of finite elements and boundary conditions, 2) calculations of eddy currents and electromagnetic forces, 3) transformation of the resultant force to load data fit to the structural analysis program, 4) structural analysis and 5) post-processing of the results. The EDDYTRAN utilizes the EDDYCUFF (EDDY CUrrent, magnetic Field and electromagnetic Force) program and the NASTRAN (NASA STRuctural ANalysis) program. Here, the EDDYCUFF program which has been developed by the authors is a generalized computer program to calculate transient eddy currents, resultant magnetic fields and electromagnetic forces in the conductive components. This paper describes the outline of the EDDYTRAN program system and preliminary results obtained through the application to the Tokamak reactor design which was performed for the Japan Atomic Energy Research Institute

Analysis of data characterizing tide and current fluxes in coastal basins

Directory of Open Access Journals (Sweden)

E. Armenio

2017-07-01

Full Text Available Many coastal monitoring programmes have been carried out to investigate in situ hydrodynamic patterns and correlated physical processes, such as sediment transport or spreading of pollutants. The key point is the necessity to transform this growing amount of data provided by marine sensors into information for users. The present paper aims to outline that it is possible to recognize the recurring and typical hydrodynamic processes of a coastal basin, by conveniently processing some selected marine field data. The illustrated framework is made up of two steps. Firstly, a sequence of analysis with classic methods characterized by low computational cost was executed in both time and frequency domains on detailed field measurements of waves, tides, and currents. After this, some indicators of the hydrodynamic state of the basin were identified and evaluated. Namely, the assessment of the net flow through a connecting channel, the time delay of current peaks between upper and bottom layers, the ratio of peak ebb and peak flood currents and the tidal asymmetry factor exemplify results on the vertical structure of the flow, on the correlation between currents and tide and flood/ebb dominance. To demonstrate how this simple and generic framework could be applied, a case study is presented, referring to Mar Piccolo, a shallow water basin located in the inner part of the Ionian Sea (southern Italy.

Analysis of data characterizing tide and current fluxes in coastal basins

Science.gov (United States)

Armenio, Elvira; De Serio, Francesca; Mossa, Michele

2017-07-01

Many coastal monitoring programmes have been carried out to investigate in situ hydrodynamic patterns and correlated physical processes, such as sediment transport or spreading of pollutants. The key point is the necessity to transform this growing amount of data provided by marine sensors into information for users. The present paper aims to outline that it is possible to recognize the recurring and typical hydrodynamic processes of a coastal basin, by conveniently processing some selected marine field data. The illustrated framework is made up of two steps. Firstly, a sequence of analysis with classic methods characterized by low computational cost was executed in both time and frequency domains on detailed field measurements of waves, tides, and currents. After this, some indicators of the hydrodynamic state of the basin were identified and evaluated. Namely, the assessment of the net flow through a connecting channel, the time delay of current peaks between upper and bottom layers, the ratio of peak ebb and peak flood currents and the tidal asymmetry factor exemplify results on the vertical structure of the flow, on the correlation between currents and tide and flood/ebb dominance. To demonstrate how this simple and generic framework could be applied, a case study is presented, referring to Mar Piccolo, a shallow water basin located in the inner part of the Ionian Sea (southern Italy).

Observation and analysis of halo current in EAST

Science.gov (United States)

Chen, Da-Long; Shen, Biao; Qian, Jin-Ping; Sun, You-Wen; Liu, Guang-Jun; Shi, Tong-Hui; Zhuang, Hui-Dong; Xiao, Bing-Jia

2014-06-01

Plasma in a typically elongated cross-section tokamak (for example, EAST) is inherently unstable against vertical displacement. When plasma loses the vertical position control, it moves downward or upward, leading to disruption, and a large halo current is generated helically in EAST typically in the scrape-off layer. When flowing into the vacuum vessel through in-vessel components, the halo current will give rise to a large J × B force acting on the vessel and the in-vessel components. In EAST VDE experiment, part of the eddy current is measured in halo sensors, due to the large loop voltage. Primary experimental data demonstrate that the halo current first lands on the outer plate and then flows clockwise, and the analysis of the information indicates that the maximum halo current estimated in EAST is about 0.4 times the plasma current and the maximum value of TPF × Ih/IP0 is 0.65, furthermore Ih/Ip0 and TPF × Ih/Ip0 tend to increase with the increase of Ip0. The test of the strong gas injection system shows good success in increasing the radiated power, which may be effective in reducing the halo current.

Analysis of plasma equilibrium based on orbit-driven current density profile in steady-state plasma on QUEST

Energy Technology Data Exchange (ETDEWEB)

Nakamura, K., E-mail: nakamura@triam.kyushu-u.ac.jp [RIAM, Kyushu University, Kasuga 816-8580 (Japan); Alam, M.M. [IGSES, Kyushu University, Kasuga 816-8580 (Japan); Jiang, Y.Z. [Tsinghua University, Beijing 100084 (China); Mitarai, O. [Tokai University, Kumamoto 862-8652 (Japan); Kurihara, K.; Kawamata, Y.; Sueoka, M.; Takechi, M. [Japan Atomic Energy Agency, Naka 311-0193 (Japan); Hasegawa, M.; Tokunaga, K.; Araki, K.; Zushi, H.; Hanada, K.; Fujisawa, A.; Idei, H.; Nagashima, Y.; Kawasaki, S.; Nakashima, H.; Higashijima, A.; Nagata, T. [RIAM, Kyushu University, Kasuga 816-8580 (Japan); and others

2016-11-01

Highlights: • High energy particle guiding center orbit is calculated as a contour plot of conserved variable. • Current density profile is analyzed based on the orbit-driven current. • Plasma equilibrium is reconstructed by considering the hollow current profile. - Abstract: In the present RF-driven (ECCD) steady-state plasma on QUEST (B{sub t} = 0.25 T, R = 0.68 m, a = 0.40 m), plasma current seems to flow in the open magnetic surface outside of the closed magnetic surface in the low-field region according to plasma current fitting (PCF) method. We consider that the current in the open magnetic surface is due to orbit-driven current by high-energy particles in RF-driven plasma. So based on the analysis of current density profile based on the orbit-driven current, plasma equilibrium is to be calculated. We calculated high energy particles guiding center orbits as a contour plot of conserved variable in Hamiltonian formulation and considered particles initial position with different levels of energy and pitch angles that satisfy resonance condition. Then the profile of orbit-driven current is estimated by multiplying the particle density on the resonance surface and the velocity on the orbits. This analysis shows negative current near the magnetic axis and hollow current profile is expected even if pressure driven current is considered. Considering the hollow current profile shifted toward the low-field region, the equilibrium is fitted by J-EFIT coded by MATLAB.

Report of a CSNI workshop on uncertainty analysis methods. Volume 1 + 2

International Nuclear Information System (INIS)

Wickett, A.J.; Yadigaroglu, G.

1994-08-01

The OECD NEA CSNI Principal Working Group 2 (PWG2) Task Group on Thermal Hydraulic System Behaviour (TGTHSB) has, in recent years, received presentations of a variety of different methods to analyze the uncertainty in the calculations of advanced unbiased (best estimate) codes. Proposals were also made for an International Standard Problem (ISP) to compare the uncertainty analysis methods. The objectives for the Workshop were to discuss and fully understand the principles of uncertainty analysis relevant to LOCA modelling and like problems, to examine the underlying issues from first principles, in preference to comparing and contrasting the currently proposed methods, to reach consensus on the issues identified as far as possible while not avoiding the controversial aspects, to identify as clearly as possible unreconciled differences, and to issue a Status Report. Eight uncertainty analysis methods were presented. A structured discussion of various aspects of uncertainty analysis followed - the need for uncertainty analysis, identification and ranking of uncertainties, characterisation, quantification and combination of uncertainties and applications, resources and future developments. As a result, the objectives set out above were, to a very large extent, achieved. Plans for the ISP were also discussed. Volume 1 contains a record of the discussions on uncertainty methods. Volume 2 is a compilation of descriptions of the eight uncertainty analysis methods presented at the workshop

New Methods for Estimating Water Current Velocity Fields from Autonomous Underwater Vehicles

Science.gov (United States)

Kinsey, J. C.; Medagoda, L.

2016-02-01

Water current velocities are a crucial component of understanding oceanographic processes and underwater robots, such as autonomous underwater vehicles (AUVs), provide a mobile platform for obtaining these observations. Estimating water current velocities requires both measurements of the water velocity, often obtained with an Acoustic Doppler Current Profiler (ADCP), as well as estimates of the vehicle velocity. Presently, vehicle velocities are supplied on the sea surface with velocity from GPS, or near the seafloor where Doppler Velocity Log (DVL) in bottom-lock is available; however, this capability is unavailable in the mid-water column where DVL bottom-lock and GPS are unavailable. Here we present a method which calculates vehicle velocities using consecutive ADCP measurements in the mid-water using an extended Kalman filter (EKF). The correlation of the spatially changing water current states, along with mass transport and shear constraints on the water current field, is formulated using least square constraints. Results from the Sentry AUV from a mid-water surveying mission at Deepwater Horizon and a small-scale hydrothermal vent flux estimation mission suggest the method is suitable for real-time use. DVL data is denied to simulate mid-water missions and the results compared to ground truth water velocity measurements estimated using DVL velocities. Results show quantifiable uncertainties in the water current velocities, along with similar performance, for the DVL and no-DVL case in the mid-water. This method has the potential to provide geo-referenced water velocity measurements from mobile ocean robots in the absence of GPS and DVL as well as estimate the uncertainty associated with the measurements.

Analysis of the EDIPO Temperature Margin During Current Ramp-Up

CERN Document Server

Marinucci, C; Calvi, Marco; Marinucci, Claudio; Cau, Francesca; Bottura, Luca

2010-01-01

The European dipole (EDIPO), currently under construction, will provide background magnetic fields of up to 12.5 T for tests of ITER high-current superconducting cables. The EDIPO winding consists of 7 x 2 double layers of Nb$_{3}$SN cable-in-conduit conductors with forced flow cooling of supercritical helium. The performance limits of EDIPO during current ramp-up are analyzed analysed with the CryoSoft suite of codes, recently integrated into a customizable and flexible environment for the analysis of thermal hydraulic and electrical transients in superconducting magnetic systems. The simultaneous analysis of the cryogenic system and all 14 double layers shows that under all charging conditions the EDIPO temperature margin remains sufficiently high.

Research on Intelligent Avoidance Method of Shipwreck Based on Bigdata Analysis

Directory of Open Access Journals (Sweden)

Li Wei

2017-11-01

Full Text Available In order to solve the problem that current avoidance method of shipwreck has the problem of low success rate of avoidance, this paper proposes a method of intelligent avoidance of shipwreck based on big data analysis. Firstly,our method used big data analysis to calculate the safe distance of approach of ship under the head-on situation, the crossing situation and the overtaking situation.On this basis, by calculating the risk-degree of collision of ships,our research determined the degree of immediate danger of ships.Finally, we calculated the three kinds of evaluation function of ship navigation, and used genetic algorithm to realize the intelligent avoidance of shipwreck.Experimental result shows that compared the proposed method with the traditional method in two in a recent meeting when the distance to closest point of approach between two ships is 0.13nmile, they can effectively evade.The success rate of avoidance is high.

Cross-Circulating Current Suppression Method for Parallel Three-Phase Two-Level Inverters

DEFF Research Database (Denmark)

Wei, Baoze; Guerrero, Josep M.; Guo, Xiaoqiang

2015-01-01

The parallel architecture is very popular for power inverters to increase the power level. This paper presents a method for the parallel operation of inverters in an ac-distributed system, to suppress the cross-circulating current based on virtual impedance without current-sharing bus...

Comparison of urine analysis using manual and sedimentation methods.

Science.gov (United States)

Kurup, R; Leich, M

2012-06-01

Microscopic examination of urine sediment is an essential part in the evaluation of renal and urinary tract diseases. Traditionally, urine sediments are assessed by microscopic examination of centrifuged urine. However the current method used by the Georgetown Public Hospital Corporation Medical Laboratory involves uncentrifuged urine. To encourage high level of care, the results provided to the physician must be accurate and reliable for proper diagnosis. The aim of this study is to determine whether the centrifuge method is more clinically significant than the uncentrifuged method. In this study, a comparison between the results obtained from centrifuged and uncentrifuged methods were performed. A total of 167 urine samples were randomly collected and analysed during the period April-May 2010 at the Medical Laboratory, Georgetown Public Hospital Corporation. The urine samples were first analysed microscopically by the uncentrifuged, and then by the centrifuged method. The results obtained from both methods were recorded in a log book. These results were then entered into a database created in Microsoft Excel, and analysed for differences and similarities using this application. Analysis was further done in SPSS software to compare the results using Pearson ' correlation. When compared using Pearson's correlation coefficient analysis, both methods showed a good correlation between urinary sediments with the exception of white bloods cells. The centrifuged method had a slightly higher identification rate for all of the parameters. There is substantial agreement between the centrifuged and uncentrifuged methods. However the uncentrifuged method provides for a rapid turnaround time.

Current matrix element in HAL QCD's wavefunction-equivalent potential method

Science.gov (United States)

Watanabe, Kai; Ishii, Noriyoshi

2018-04-01

We give a formula to calculate a matrix element of a conserved current in the effective quantum mechanics defined by the wavefunction-equivalent potentials proposed by the HAL QCD collaboration. As a first step, a non-relativistic field theory with two-channel coupling is considered as the original theory, with which a wavefunction-equivalent HAL QCD potential is obtained in a closed analytic form. The external field method is used to derive the formula by demanding that the result should agree with the original theory. With this formula, the matrix element is obtained by sandwiching the effective current operator between the left and right eigenfunctions of the effective Hamiltonian associated with the HAL QCD potential. In addition to the naive one-body current, the effective current operator contains an additional two-body term emerging from the degrees of freedom which has been integrated out.

Coloured Petri Nets: Basic Concepts, Analysis Methods and Practical Use. Vol. 2, Analysis Methods

DEFF Research Database (Denmark)

Jensen, Kurt

ideas behind the analysis methods are described as well as the mathematics on which they are based and also how the methods are supported by computer tools. Some parts of the volume are theoretical while others are application oriented. The purpose of the volume is to teach the reader how to use......This three-volume work presents a coherent description of the theoretical and practical aspects of coloured Petri nets (CP-nets). The second volume contains a detailed presentation of the analysis methods for CP-nets. They allow the modeller to investigate dynamic properties of CP-nets. The main...... the formal analysis methods, which does not require a deep understanding of the underlying mathematical theory....

System and method for bearing fault detection using stator current noise cancellation

Science.gov (United States)

Zhou, Wei; Lu, Bin; Habetler, Thomas G.; Harley, Ronald G.; Theisen, Peter J.

2010-08-17

A system and method for detecting incipient mechanical motor faults by way of current noise cancellation is disclosed. The system includes a controller configured to detect indicia of incipient mechanical motor faults. The controller further includes a processor programmed to receive a baseline set of current data from an operating motor and define a noise component in the baseline set of current data. The processor is also programmed to repeatedly receive real-time operating current data from the operating motor and remove the noise component from the operating current data in real-time to isolate any fault components present in the operating current data. The processor is then programmed to generate a fault index for the operating current data based on any isolated fault components.

Discrimination Between Inrush and Short Circuit Currents in Differential Protection of Power Transformer Based on Correlation Method Using the Wavelet Transform

OpenAIRE

M. Rasoulpoor; M. Banejad; A. Ahmadyfard

2011-01-01

This paper presents a novel technique for transformer differential protection to prevent incorrect operation due to inrush current. The proposed method in this paper is based on time-frequency transform known as the Wavelet transform. The discrete Wavelet transform is used for analysis the differential current signals in time and frequency domains. The investigation on the energy distribution of the signal on the discrete Wavelet transform components shows the difference distribution between ...

A pre-heating method based on sinusoidal alternating current for lithium-ion battery

Science.gov (United States)

Fan, Wentao; Sun, Fengchun; Guo, Shanshan

2018-04-01

In this paper, a method of low temperature pre-heating of sinusoidal alternating current (SAC) is proposed. Generally, the lower the frequency of the AC current, the higher the heat generation rate. Yet at low frequency, there is a risk of lithium-ion deposition during the half cycle of charging. This study develops a temperature-adaptive, deposition-free AC pre-heating method. a equivalent electric circuit(EEC) model is established to predict the heat generation rate and temperature status, whose parameters are calibrated from the EIS impedance measurements. The effects of current frequency and amplitude on the heating effect are investigated respectively. A multistep temperature-adaptive amplitude strategy is proposed and the cell can be heated from -20°C to 5°C within 509s at 100Hz frequency with this method.

Analysis of methods. [information systems evolution environment

Science.gov (United States)

Mayer, Richard J. (Editor); Ackley, Keith A.; Wells, M. Sue; Mayer, Paula S. D.; Blinn, Thomas M.; Decker, Louis P.; Toland, Joel A.; Crump, J. Wesley; Menzel, Christopher P.; Bodenmiller, Charles A.

1991-01-01

Information is one of an organization's most important assets. For this reason the development and maintenance of an integrated information system environment is one of the most important functions within a large organization. The Integrated Information Systems Evolution Environment (IISEE) project has as one of its primary goals a computerized solution to the difficulties involved in the development of integrated information systems. To develop such an environment a thorough understanding of the enterprise's information needs and requirements is of paramount importance. This document is the current release of the research performed by the Integrated Development Support Environment (IDSE) Research Team in support of the IISEE project. Research indicates that an integral part of any information system environment would be multiple modeling methods to support the management of the organization's information. Automated tool support for these methods is necessary to facilitate their use in an integrated environment. An integrated environment makes it necessary to maintain an integrated database which contains the different kinds of models developed under the various methodologies. In addition, to speed the process of development of models, a procedure or technique is needed to allow automatic translation from one methodology's representation to another while maintaining the integrity of both. The purpose for the analysis of the modeling methods included in this document is to examine these methods with the goal being to include them in an integrated development support environment. To accomplish this and to develop a method for allowing intra-methodology and inter-methodology model element reuse, a thorough understanding of multiple modeling methodologies is necessary. Currently the IDSE Research Team is investigating the family of Integrated Computer Aided Manufacturing (ICAM) DEFinition (IDEF) languages IDEF(0), IDEF(1), and IDEF(1x), as well as ENALIM, Entity

Methods of Multivariate Analysis

CERN Document Server

Rencher, Alvin C

2012-01-01

Praise for the Second Edition "This book is a systematic, well-written, well-organized text on multivariate analysis packed with intuition and insight . . . There is much practical wisdom in this book that is hard to find elsewhere."-IIE Transactions Filled with new and timely content, Methods of Multivariate Analysis, Third Edition provides examples and exercises based on more than sixty real data sets from a wide variety of scientific fields. It takes a "methods" approach to the subject, placing an emphasis on how students and practitioners can employ multivariate analysis in real-life sit

Multivariate analysis: models and method

International Nuclear Information System (INIS)

Sanz Perucha, J.

1990-01-01

Data treatment techniques are increasingly used since computer methods result of wider access. Multivariate analysis consists of a group of statistic methods that are applied to study objects or samples characterized by multiple values. A final goal is decision making. The paper describes the models and methods of multivariate analysis

An Excel‐based implementation of the spectral method of action potential alternans analysis

Science.gov (United States)

Pearman, Charles M.

2014-01-01

Abstract Action potential (AP) alternans has been well established as a mechanism of arrhythmogenesis and sudden cardiac death. Proper interpretation of AP alternans requires a robust method of alternans quantification. Traditional methods of alternans analysis neglect higher order periodicities that may have greater pro‐arrhythmic potential than classical 2:1 alternans. The spectral method of alternans analysis, already widely used in the related study of microvolt T‐wave alternans, has also been used to study AP alternans. Software to meet the specific needs of AP alternans analysis is not currently available in the public domain. An AP analysis tool is implemented here, written in Visual Basic for Applications and using Microsoft Excel as a shell. This performs a sophisticated analysis of alternans behavior allowing reliable distinction of alternans from random fluctuations, quantification of alternans magnitude, and identification of which phases of the AP are most affected. In addition, the spectral method has been adapted to allow detection and quantification of higher order regular oscillations. Analysis of action potential morphology is also performed. A simple user interface enables easy import, analysis, and export of collated results. PMID:25501439

Quantification and Analysis of Suspended Sediments Concentration Using Mobile and Static Acoustic Doppler Current Profiler Instruments

Directory of Open Access Journals (Sweden)

Angga Dwinovantyo

2017-01-01

Full Text Available The application of Acoustic Doppler Current Profiler (ADCP can be used not only for measuring ocean currents, but also for quantifying suspended sediment concentrations (SSC from acoustic backscatter strength based on sonar principle. Suspended sediment has long been recognized as the largest sources of sea contaminant and must be considered as one of the important parameters in water quality of seawater. This research was to determine SSC from measured acoustic backscattered intensity of static and mobile ADCP. In this study, vertically mounted 400 kHz and 750 kHz static ADCP were deployed in Lembeh Strait, North Sulawesi. A mobile ADCP 307.2 kHz was also mounted on the boat and moved to the predefined cross-section, accordingly. The linear regression analysis of echo intensity measured by ADCP and by direct measurement methods showed that ADCP is a reliable method to measure SSC with correlation coefficient (r 0.92. Higher SSC was observed in low water compared to that in high water and near port area compared to those in observed areas. All of this analysis showed that the combination of static and mobile ADCP methods produces reasonably good spatial and temporal data of SSC.

Current Sharing Analysis of Arm Prototype for ITER PF Converter Bridge

International Nuclear Information System (INIS)

Li Jinchao; Song Zhiquan; Xu Liuwei; Fu Peng; Guo Bin; Li Sen; Dong Lin; Wang Min

2014-01-01

A bridge arm prototype of ITER poloidal field (PF) converter modules has been designed and fabricated. Non-cophase counter parallel connection is chosen as the arm structure of the prototype. Among all factors affecting current sharing, arm structure is the main one. During the design of the arm prototype, a novel method based on inductance matrixes is employed to improve the current sharing of the bridge arm. The test results on the prototype show that the current sharing performance of the arm prototype is much better than relevant design requirement, and that the matrix method is very effective to analyze and solve the current sharing problems of thyristor converters

Mendelian randomization analysis of a time-varying exposure for binary disease outcomes using functional data analysis methods.

Science.gov (United States)

Cao, Ying; Rajan, Suja S; Wei, Peng

2016-12-01

A Mendelian randomization (MR) analysis is performed to analyze the causal effect of an exposure variable on a disease outcome in observational studies, by using genetic variants that affect the disease outcome only through the exposure variable. This method has recently gained popularity among epidemiologists given the success of genetic association studies. Many exposure variables of interest in epidemiological studies are time varying, for example, body mass index (BMI). Although longitudinal data have been collected in many cohort studies, current MR studies only use one measurement of a time-varying exposure variable, which cannot adequately capture the long-term time-varying information. We propose using the functional principal component analysis method to recover the underlying individual trajectory of the time-varying exposure from the sparsely and irregularly observed longitudinal data, and then conduct MR analysis using the recovered curves. We further propose two MR analysis methods. The first assumes a cumulative effect of the time-varying exposure variable on the disease risk, while the second assumes a time-varying genetic effect and employs functional regression models. We focus on statistical testing for a causal effect. Our simulation studies mimicking the real data show that the proposed functional data analysis based methods incorporating longitudinal data have substantial power gains compared to standard MR analysis using only one measurement. We used the Framingham Heart Study data to demonstrate the promising performance of the new methods as well as inconsistent results produced by the standard MR analysis that relies on a single measurement of the exposure at some arbitrary time point. © 2016 WILEY PERIODICALS, INC.

A new method for electric impedance imaging using an eddy current with a tetrapolar circuit.

Science.gov (United States)

Ahsan-Ul-Ambia; Toda, Shogo; Takemae, Tadashi; Kosugi, Yukio; Hongo, Minoru

2009-02-01

A new contactless technique for electrical impedance imaging, using an eddy current managed along with the tetrapolar circuit method, is proposed. The eddy current produced by a magnetic field is superimposed on a constant current that is normally used in the tetrapolar circuit method, and thus is used to control the current distribution in the body. By changing the current distribution, a set of voltage differences is measured with a pair of electrodes. This set of voltage differences is used in the image reconstruction of the resistivity distribution. The least square error minimization method is used in the reconstruction algorithm. The principle of this method is explained theoretically. A backprojection algorithm was used to get 2-D images. Based on this principle, a measurement system was developed and model experiments were conducted with a saline-filled phantom. The estimated shape of each model in the reconstructed image was similar to that of the corresponding model. From the results of these experiments, it is confirmed that the proposed method is applicable to the realization of electrical conductivity imaging.

Extracting functional components of neural dynamics with Independent Component Analysis and inverse Current Source Density.

Science.gov (United States)

Lęski, Szymon; Kublik, Ewa; Swiejkowski, Daniel A; Wróbel, Andrzej; Wójcik, Daniel K

2010-12-01

Local field potentials have good temporal resolution but are blurred due to the slow spatial decay of the electric field. For simultaneous recordings on regular grids one can reconstruct efficiently the current sources (CSD) using the inverse Current Source Density method (iCSD). It is possible to decompose the resultant spatiotemporal information about the current dynamics into functional components using Independent Component Analysis (ICA). We show on test data modeling recordings of evoked potentials on a grid of 4 × 5 × 7 points that meaningful results are obtained with spatial ICA decomposition of reconstructed CSD. The components obtained through decomposition of CSD are better defined and allow easier physiological interpretation than the results of similar analysis of corresponding evoked potentials in the thalamus. We show that spatiotemporal ICA decompositions can perform better for certain types of sources but it does not seem to be the case for the experimental data studied. Having found the appropriate approach to decomposing neural dynamics into functional components we use the technique to study the somatosensory evoked potentials recorded on a grid spanning a large part of the forebrain. We discuss two example components associated with the first waves of activation of the somatosensory thalamus. We show that the proposed method brings up new, more detailed information on the time and spatial location of specific activity conveyed through various parts of the somatosensory thalamus in the rat.

Analysis apparatus and method of analysis

International Nuclear Information System (INIS)

1976-01-01

A continuous streaming method developed for the excution of immunoassays is described in this patent. In addition, a suitable apparatus for the method was developed whereby magnetic particles are automatically employed for the consecutive analysis of a series of liquid samples via the RIA technique

Pulsed Direct Current Electrospray: Enabling Systematic Analysis of Small Volume Sample by Boosting Sample Economy.

Science.gov (United States)

Wei, Zhenwei; Xiong, Xingchuang; Guo, Chengan; Si, Xingyu; Zhao, Yaoyao; He, Muyi; Yang, Chengdui; Xu, Wei; Tang, Fei; Fang, Xiang; Zhang, Sichun; Zhang, Xinrong

2015-11-17

We had developed pulsed direct current electrospray ionization mass spectrometry (pulsed-dc-ESI-MS) for systematically profiling and determining components in small volume sample. Pulsed-dc-ESI utilized constant high voltage to induce the generation of single polarity pulsed electrospray remotely. This method had significantly boosted the sample economy, so as to obtain several minutes MS signal duration from merely picoliter volume sample. The elongated MS signal duration enable us to collect abundant MS(2) information on interested components in a small volume sample for systematical analysis. This method had been successfully applied for single cell metabolomics analysis. We had obtained 2-D profile of metabolites (including exact mass and MS(2) data) from single plant and mammalian cell, concerning 1034 components and 656 components for Allium cepa and HeLa cells, respectively. Further identification had found 162 compounds and 28 different modification groups of 141 saccharides in a single Allium cepa cell, indicating pulsed-dc-ESI a powerful tool for small volume sample systematical analysis.

New method for determining central axial orientation of flux rope embedded within current sheet using multipoint measurements

Science.gov (United States)

Li, ZhaoYu; Chen, Tao; Yan, GuangQing

2016-10-01

A new method for determining the central axial orientation of a two-dimensional coherent magnetic flux rope (MFR) via multipoint analysis of the magnetic-field structure is developed. The method is devised under the following geometrical assumptions: (1) on its cross section, the structure is left-right symmetric; (2) the projected structure velocity is vertical to the line of symmetry. The two conditions can be naturally satisfied for cylindrical MFRs and are expected to be satisfied for MFRs that are flattened within current sheets. The model test demonstrates that, for determining the axial orientation of such structures, the new method is more efficient and reliable than traditional techniques such as minimum-variance analysis of the magnetic field, Grad-Shafranov (GS) reconstruction, and the more recent method based on the cylindrically symmetric assumption. A total of five flux transfer events observed by Cluster are studied using the proposed approach, and the application results indicate that the observed structures, regardless of their actual physical properties, fit the assumed geometrical model well. For these events, the inferred axial orientations are all in excellent agreement with those obtained using the multi-GS reconstruction technique.

Reactor coolant pump testing using motor current signatures analysis

Energy Technology Data Exchange (ETDEWEB)

Burstein, N.; Bellamy, J.

1996-12-01

This paper describes reactor coolant pump motor testing carried out at Florida Power Corporation`s Crystal River plant using Framatome Technologies` new EMPATH (Electric Motor Performance Analysis and Trending Hardware) system. EMPATH{trademark} uses an improved form of Motor Current Signature Analysis (MCSA), technology, originally developed at Oak Ridge National Laboratories, for detecting deterioration in the rotors of AC induction motors. Motor Current Signature Analysis (MCSA) is a monitoring tool for motor driven equipment that provides a non-intrusive means for detecting the presence of mechanical and electrical abnormalities in the motor and the driven equipment. The base technology was developed at the Oak Ridge National Laboratory as a means for determining the affects of aging and service wear specifically on motor-operated valves used in nuclear power plant safety systems, but it is applicable to a broad range of electric machinery. MCSA is based on the recognition that an electric motor (ac or dc) driving a mechanical load acts as an efficient and permanently available transducer by sensing mechanical load variations, large and small, long-term and rapid, and converting them into variations in the induced current generated in the motor windings. The motor current variations, resulting from changes in load caused by gears, pulleys, friction, bearings, and other conditions that may change over the life of the motor, are carried by the electrical cables powering the motor and are extracted at any convenient location along the motor lead. These variations modulate the 60 Hz carrier frequency and appear as sidebands in the spectral plot.

Transuranic waste characterization sampling and analysis methods manual. Revision 1

International Nuclear Information System (INIS)

Suermann, J.F.

1996-04-01

This Methods Manual provides a unified source of information on the sampling and analytical techniques that enable Department of Energy (DOE) facilities to comply with the requirements established in the current revision of the Transuranic Waste Characterization Quality Assurance Program Plan (QAPP) for the Waste Isolation Pilot Plant (WIPP) Transuranic (TRU) Waste Characterization Program (the Program) and the WIPP Waste Analysis Plan. This Methods Manual includes all of the testing, sampling, and analytical methodologies accepted by DOE for use in implementing the Program requirements specified in the QAPP and the WIPP Waste Analysis Plan. The procedures in this Methods Manual are comprehensive and detailed and are designed to provide the necessary guidance for the preparation of site-specific procedures. With some analytical methods, such as Gas Chromatography/Mass Spectrometry, the Methods Manual procedures may be used directly. With other methods, such as nondestructive characterization, the Methods Manual provides guidance rather than a step-by-step procedure. Sites must meet all of the specified quality control requirements of the applicable procedure. Each DOE site must document the details of the procedures it will use and demonstrate the efficacy of such procedures to the Manager, National TRU Program Waste Characterization, during Waste Characterization and Certification audits

Current breathomics-a review on data pre-processing techniques and machine learning in metabolomics breath analysis

DEFF Research Database (Denmark)

Smolinska, A.; Hauschild, A. C.; Fijten, R. R. R.

2014-01-01

been extensively developed. Yet, the application of machine learning methods for fingerprinting VOC profiles in the breathomics is still in its infancy. Therefore, in this paper, we describe the current state of the art in data pre-processing and multivariate analysis of breathomics data. We start...... different conditions (e.g. disease stage, treatment). Independently of the utilized analytical method, the most important question, 'which VOCs are discriminatory?', remains the same. Answers can be given by several modern machine learning techniques (multivariate statistics) and, therefore, are the focus...

A Method for Eddy Current Field Measurement in Permanent Magnet Magnetic Resonance Imaging Systems

Directory of Open Access Journals (Sweden)

SONG Rui

2018-03-01

Full Text Available Magnetic resonance imaging (MRI is a widely used medical imaging technique. In MRI system, gradient magnetic fields are used to code spatial information. However, the fast-switching electric currents in the gradients coils used to generate gradient fields also induce vortex electric field, often referred as eddy current, in the surrounding metal conductors. In this paper, a method for eddy current field measurement was proposed. Based on the Faraday law of electromagnetic induction, an eddy current field measuring device was designed. Combining hardware acquisition and software processing, the eddy current field was obtained by subtracting the ideal gradient field from the magnetic field measured experimentally, whose waveform could be displayed in real time. The proposed method was verified by experimental results.

Measurement and statistical analysis of single-molecule current-voltage characteristics, transition voltage spectroscopy, and tunneling barrier height.

Science.gov (United States)

Guo, Shaoyin; Hihath, Joshua; Díez-Pérez, Ismael; Tao, Nongjian

2011-11-30

We report on the measurement and statistical study of thousands of current-voltage characteristics and transition voltage spectra (TVS) of single-molecule junctions with different contact geometries that are rapidly acquired using a new break junction method at room temperature. This capability allows one to obtain current-voltage, conductance voltage, and transition voltage histograms, thus adding a new dimension to the previous conductance histogram analysis at a fixed low-bias voltage for single molecules. This method confirms the low-bias conductance values of alkanedithiols and biphenyldithiol reported in literature. However, at high biases the current shows large nonlinearity and asymmetry, and TVS allows for the determination of a critically important parameter, the tunneling barrier height or energy level alignment between the molecule and the electrodes of single-molecule junctions. The energy level alignment is found to depend on the molecule and also on the contact geometry, revealing the role of contact geometry in both the contact resistance and energy level alignment of a molecular junction. Detailed statistical analysis further reveals that, despite the dependence of the energy level alignment on contact geometry, the variation in single-molecule conductance is primarily due to contact resistance rather than variations in the energy level alignment.

Measuring electric conductivity in liquid metals by eddy current method

International Nuclear Information System (INIS)

Zhuravlev, S.P.; Ostrovskij, O.I.; Grigoryan, V.A.

1982-01-01

Technique permitting to apply the method of vertiginous currents for investigation of electric conductivity of metal melts in the high temperature range is presented. Interferences affecting accuracy of measurements are specified and ways of their removing are pointed out. Scheme of measuring and design of the facility are described. Results of measuring electric resistance of liquid Fe, Co, Ni obtained for the first time by this method are presented. The data obtained agree with the results of measurements conducted by the method of the rotating magnetic field. Difference in absolute values of electric resistance in parallel experiments for each metal does not exceed 4%

The JET Intershot Analysis: Current infrastructure and future plans

International Nuclear Information System (INIS)

Layne, R.; Cook, N.; Harting, D.; McDonald, D.C.; Tidy, C.

2010-01-01

The JET Intershot Analysis (Chain1) generates processed data following a pulse. Maintaining the pulse repetition rate is one of JET's key success factors, so performance of Chain1 is crucial. This paper will describe JET's experience of managing Chain1, including a description of the control system used to ensure the analysis chain runs as quickly as possible, and a discussion of JET's experience of integrating externally developed codes into a standard analysis framework. The current Chain1 infrastructure was developed in 1999 and although reliable and efficient is starting to prove costly in terms of flexibility and extensibility to meet JET's current and future needs. For this reason JET is planning to re-implement the Chain1 system. The paper will outline the work done towards this aim, and present a model of the proposed new system. Finally, possible future steps towards an integrated data production chain for JET will be discussed, and the potential applicability to next generation fusion devices will be outlined.

System and method for motor fault detection using stator current noise cancellation

Science.gov (United States)

Zhou, Wei; Lu, Bin; Nowak, Michael P.; Dimino, Steven A.

2010-12-07

A system and method for detecting incipient mechanical motor faults by way of current noise cancellation is disclosed. The system includes a controller configured to detect indicia of incipient mechanical motor faults. The controller further includes a processor programmed to receive a baseline set of current data from an operating motor and define a noise component in the baseline set of current data. The processor is also programmed to acquire at least on additional set of real-time operating current data from the motor during operation, redefine the noise component present in each additional set of real-time operating current data, and remove the noise component from the operating current data in real-time to isolate any fault components present in the operating current data. The processor is then programmed to generate a fault index for the operating current data based on any isolated fault components.

Analysis methods for fast impurity ion dynamics data

International Nuclear Information System (INIS)

Den Hartog, D.J.; Almagri, A.F.; Prager, S.C.; Fonck, R.J.

1994-08-01

A high resolution spectrometer has been developed and used on the MST reversed-field pinch (RFP) to measure passively impurity ion temperatures and flow velocities with 10 μs temporal resolution. Such measurements of MHD-scale fluctuations are particularly relevant in the RFP because the flow velocity fluctuation induced transport of current (the ''MHD dynamo'') may produce the magnetic field reversal characteristic of an RFP. This instrument will also be used to measure rapid changes in the equilibrium flow velocity, such as occur during locking and H-mode transition. The precision of measurements made to date is <0.6 km/s. The authors are developing accurate analysis techniques appropriate to the reduction of this fast ion dynamics data. Moment analysis and curve-fitting routines have been evaluated for noise sensitivity and robustness. Also presented is an analysis method which correctly separates the flux-surface average of the correlated fluctuations in u and B from the fluctuations due to rigid shifts of the plasma column

Statistical analysis of storm-time near-Earth current systems

Directory of Open Access Journals (Sweden)

M. W. Liemohn

2015-08-01

Full Text Available Currents from the Hot Electron and Ion Drift Integrator (HEIDI inner magnetospheric model results for all of the 90 intense storms (disturbance storm-time (Dst minimum < −100 nT from solar cycle 23 (1996–2005 are calculated, presented, and analyzed. We have categorized these currents into the various systems that exist in near-Earth space, specifically the eastward and westward symmetric ring current, the partial ring current, the banana current, and the tail current. The current results from each run set are combined by a normalized superposed epoch analysis technique that scales the timeline of each phase of each storm before summing the results. It is found that there is a systematic ordering to the current systems, with the asymmetric current systems peaking during storm main phase (tail current rising first, then the banana current, followed by the partial ring current and the symmetric current systems peaking during the early recovery phase (westward and eastward symmetric ring current having simultaneous maxima. The median and mean peak amplitudes for the current systems ranged from 1 to 3 MA, depending on the setup configuration used in HEIDI, except for the eastward symmetric ring current, for which the mean never exceeded 0.3 MA for any HEIDI setup. The self-consistent electric field description in HEIDI yielded larger tail and banana currents than the Volland–Stern electric field, while the partial and symmetric ring currents had similar peak values between the two applied electric field models.

System and method for quench and over-current protection of superconductor

Science.gov (United States)

Huang, Xianrui; Laskaris, Evangelos Trifon; Sivasubramaniam, Kiruba Haran; Bray, James William; Ryan, David Thomas; Fogarty, James Michael; Steinbach, Albert Eugene

2005-05-31

A system and method for protecting a superconductor. The system may comprise a current sensor operable to detect a current flowing through the superconductor. The system may comprise a coolant temperature sensor operable to detect the temperature of a cryogenic coolant used to cool the superconductor to a superconductive state. The control circuit is operable to estimate the superconductor temperature based on the current flow and the coolant temperature. The system may also be operable to compare the estimated superconductor temperature to at least one threshold temperature and to initiate a corrective action when the superconductor temperature exceeds the at least one threshold temperature.

Fault identification in crystalline silicon PV modules by complementary analysis of the light and dark current-voltage characteristics

DEFF Research Database (Denmark)

Spataru, Sergiu; Sera, Dezso; Hacke, Peter

2016-01-01

This article proposes a fault identification method, based on the complementary analysis of the light and dark current-voltage (I-V) characteristics of the photovoltaic (PV) module, to distinguish between four important degradation modes that lead to power loss in PV modules: (a) degradation of t...

Location estimation method of steam leak in pipeline using leakage area analysis

International Nuclear Information System (INIS)

Kim, Se Oh; Jeon, Hyeong Seop; Son, Ki Sung; Park, Jong Won

2016-01-01

It is important to have a pipeline leak-detection system that determines the presence of a leak and quickly identifies its location. Current leak detection methods use a acoustic emission sensors, microphone arrays, and camera images. Recently, many researchers have been focusing on using cameras for detecting leaks. The advantage of this method is that it can survey a wide area and monitor a pipeline over a long distance. However, conventional methods using camera monitoring are unable to target an exact leak location. In this paper, we propose a method of detecting leak locations using leak-detection results combined with multi-frame analysis. The proposed method is verified by experiment

Location estimation method of steam leak in pipeline using leakage area analysis

Energy Technology Data Exchange (ETDEWEB)

Kim, Se Oh; Jeon, Hyeong Seop; Son, Ki Sung [Sae An Engineering Corp., Seoul (Korea, Republic of); Park, Jong Won [Dept. of Information Communications Engineering, Chungnam National University, Daejeon (Korea, Republic of)

2016-10-15

It is important to have a pipeline leak-detection system that determines the presence of a leak and quickly identifies its location. Current leak detection methods use a acoustic emission sensors, microphone arrays, and camera images. Recently, many researchers have been focusing on using cameras for detecting leaks. The advantage of this method is that it can survey a wide area and monitor a pipeline over a long distance. However, conventional methods using camera monitoring are unable to target an exact leak location. In this paper, we propose a method of detecting leak locations using leak-detection results combined with multi-frame analysis. The proposed method is verified by experiment.

Current work in energy analysis

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-03-01

This report describes the work performed at Berkeley Lab most recently. One of the Labs accomplishments is the publication of Scenarios of US Carbon Reductions, an analysis of the potential of energy technologies to reduce carbon emissions in the US. This analysis is described and played a key role in shaping the US position on climate change in the Kyoto Protocol negotiations. The Labs participation in the fundamental characterization of the climate change issue by the IPCC is described. Described also is a study of leaking electricity, which is stimulating an international campaign for a one-watt ceiling for standby electricity losses from appliances. This ceiling has the potential to save two-thirds of the 5% of US residential electricity currently expended on standby losses. The 54 vignettes contained in the report summarize results of research activities ranging in scale from calculating the efficacy of individual lamp ballasts to estimating the cost-effectiveness of the national Energy Star{reg_sign} labeling program, and ranging in location from a scoping study of energy-efficiency market transformation in California to development of an energy-efficiency project in the auto parts industry in Shandong Province, China.

Analysis by nuclear reactions and activations. A current bibliography

International Nuclear Information System (INIS)

Bujdoso, E.

2001-01-01

A current bibliography based on INIS Atomindex with 78 references on Analysis by nuclear reactions and activations has been prepared for year 1998. References are arranged by first authors' name. (N.T.)

New Passive Filter Design Method for Overvoltage Suppression and Bearing Currents Mitigation in a Long Cable Based PWM Inverter-Fed Motor Drive System

DEFF Research Database (Denmark)

Jiang, Yanmin; Wu, Weimin; He, Yuanbin

2017-01-01

would cause serious deterioration of the motor and cable. A passive overvoltage suppression technique of low-loss 'RL-plus-C' filter was proposed recently. It has not only some merits of simple structure, low cost, and good robustness, but also a significant merit of low power dissipation. In order...... to further mitigate the bearing currents, this paper proposes two new power filters and their design method. The theoretical analysis and the design method are introduced in detail. Experimental results are in good agreement with the theoretical analysis....

Exergy analysis of heating, refrigerating and air conditioning methods and applications

CERN Document Server

Dincer, Ibrahim

2015-01-01

Improve and optimize efficiency of HVAC and related energy systems from an exergy perspective. From fundamentals to advanced applications, Exergy Analysis of Heating, Air Conditioning, and Refrigeration provides readers with a clear and concise description of exergy analysis and its many uses. Focusing on the application of exergy methods to the primary technologies for heating, refrigerating, and air conditioning, Ibrahim Dincer and Marc A. Rosen demonstrate exactly how exergy can help improve and optimize efficiency, environmental performance, and cost-effectiveness. The book also discusses the analysis tools available, and includes many comprehensive case studies on current and emerging systems and technologies for real-world examples. From introducing exergy and thermodynamic fundamentals to presenting the use of exergy methods for heating, refrigeration, and air conditioning systems, this book equips any researcher or practicing engineer with the tools needed to learn and master the application of exergy...

Issues in benchmarking human reliability analysis methods: A literature review

International Nuclear Information System (INIS)

Boring, Ronald L.; Hendrickson, Stacey M.L.; Forester, John A.; Tran, Tuan Q.; Lois, Erasmia

2010-01-01

There is a diversity of human reliability analysis (HRA) methods available for use in assessing human performance within probabilistic risk assessments (PRA). Due to the significant differences in the methods, including the scope, approach, and underlying models, there is a need for an empirical comparison investigating the validity and reliability of the methods. To accomplish this empirical comparison, a benchmarking study comparing and evaluating HRA methods in assessing operator performance in simulator experiments is currently underway. In order to account for as many effects as possible in the construction of this benchmarking study, a literature review was conducted, reviewing past benchmarking studies in the areas of psychology and risk assessment. A number of lessons learned through these studies is presented in order to aid in the design of future HRA benchmarking endeavors.

Issues in benchmarking human reliability analysis methods : a literature review.

Energy Technology Data Exchange (ETDEWEB)

Lois, Erasmia (US Nuclear Regulatory Commission); Forester, John Alan; Tran, Tuan Q. (Idaho National Laboratory, Idaho Falls, ID); Hendrickson, Stacey M. Langfitt; Boring, Ronald L. (Idaho National Laboratory, Idaho Falls, ID)

2008-04-01

There is a diversity of human reliability analysis (HRA) methods available for use in assessing human performance within probabilistic risk assessment (PRA). Due to the significant differences in the methods, including the scope, approach, and underlying models, there is a need for an empirical comparison investigating the validity and reliability of the methods. To accomplish this empirical comparison, a benchmarking study is currently underway that compares HRA methods with each other and against operator performance in simulator studies. In order to account for as many effects as possible in the construction of this benchmarking study, a literature review was conducted, reviewing past benchmarking studies in the areas of psychology and risk assessment. A number of lessons learned through these studies are presented in order to aid in the design of future HRA benchmarking endeavors.

Stator current harmonics evolution by neural network method based on CFE/SS algorithm for ACEC generator of Rey Power Plant

International Nuclear Information System (INIS)

Soleymani, S.; Ranjbar, A.M.; Mirabedini, H.

2001-01-01

One method for on-line fault diagnosis in synchronous generator is stator current harmonics analysis. Then artificial neural network is considered in this paper in order to evaluate stator current harmonics in different loads. Training set of artificial neural network is made ready by generator modeling, finite element method and state space model. Many points from generator capability curve are used in order to complete this set. Artificial neural network which is used in this paper is a percept ron network with a single hidden layer, Eight hidden neurons and back propagation algorithm. Results are indicated that the trained artificial neural network can identify stator current harmonics for arbitrary load from the capability curve. The error is less than 10% in comparison with values obtained directly from the CFE-SS algorithm. The rating parameters of modeled generator are 43950 (kV A), 11(KV), 3000 (rpm), 50 (H Z), (P F=0.8)

The analysis of toxic connections content in water by spectral methods

Science.gov (United States)

Plotnikova, I. V.; Chaikovskaya, O. N.; Sokolova, I. V.; Artyushin, V. R.

2017-08-01

The current state of ecology means the strict observance of measures for the utilization of household and industrial wastes that is connected with very essential expenses of means and time. Thanks to spectroscopic devices usage the spectral methods allow to carry out the express quantitative and qualitative analysis in a workplace and field conditions. In a work the application of spectral methods by studying the degradation of toxic organic compounds after preliminary radiation of various sources is shown. Experimental data of optical density of water at various influences are given.

An Excel-based implementation of the spectral method of action potential alternans analysis.

Science.gov (United States)

Pearman, Charles M

2014-12-01

Action potential (AP) alternans has been well established as a mechanism of arrhythmogenesis and sudden cardiac death. Proper interpretation of AP alternans requires a robust method of alternans quantification. Traditional methods of alternans analysis neglect higher order periodicities that may have greater pro-arrhythmic potential than classical 2:1 alternans. The spectral method of alternans analysis, already widely used in the related study of microvolt T-wave alternans, has also been used to study AP alternans. Software to meet the specific needs of AP alternans analysis is not currently available in the public domain. An AP analysis tool is implemented here, written in Visual Basic for Applications and using Microsoft Excel as a shell. This performs a sophisticated analysis of alternans behavior allowing reliable distinction of alternans from random fluctuations, quantification of alternans magnitude, and identification of which phases of the AP are most affected. In addition, the spectral method has been adapted to allow detection and quantification of higher order regular oscillations. Analysis of action potential morphology is also performed. A simple user interface enables easy import, analysis, and export of collated results. © 2014 The Author. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Basic methods of isotope analysis

International Nuclear Information System (INIS)

Ochkin, A.V.; Rozenkevich, M.B.

2000-01-01

The bases of the most applied methods of the isotope analysis are briefly presented. The possibilities and analytical characteristics of the mass-spectrometric, spectral, radiochemical and special methods of the isotope analysis, including application of the magnetic resonance, chromatography and refractometry, are considered [ru

An improved method for quantitative magneto-optical analysis of superconductors

International Nuclear Information System (INIS)

Laviano, F; Botta, D; Chiodoni, A; Gerbaldo, R; Ghigo, G; Gozzelino, L; Zannella, S; Mezzetti, E

2003-01-01

We report on the analysis method to extract quantitative local electrodynamics in superconductors by means of the magneto-optical technique. First of all, we discuss the calibration procedure to convert the local light intensity values into magnetic induction field distribution and start focusing on the role played by the generally disregarded magnetic induction components parallel to the indicator film plane (in-plane field effect). To account for the reliability of the whole technique, the method used to reconstruct the electrical current density distribution is reported, together with a numerical test example. The methodology is applied to measure local magnetic field and current distributions on a typical YBa 2 Cu 3 O 7-x good quality film. We show how the in-plane field influences the MO measurements, after which we present an algorithm to account for the in-plane field components. The meaningful impact of the correction on the experimental results is shown. Afterwards, we discuss some aspects about the electrodynamics of the superconducting sample

Uncertainty estimates of purity measurements based on current information: toward a "live validation" of purity methods.

Science.gov (United States)

Apostol, Izydor; Kelner, Drew; Jiang, Xinzhao Grace; Huang, Gang; Wypych, Jette; Zhang, Xin; Gastwirt, Jessica; Chen, Kenneth; Fodor, Szilan; Hapuarachchi, Suminda; Meriage, Dave; Ye, Frank; Poppe, Leszek; Szpankowski, Wojciech

2012-12-01

To predict precision and other performance characteristics of chromatographic purity methods, which represent the most widely used form of analysis in the biopharmaceutical industry. We have conducted a comprehensive survey of purity methods, and show that all performance characteristics fall within narrow measurement ranges. This observation was used to develop a model called Uncertainty Based on Current Information (UBCI), which expresses these performance characteristics as a function of the signal and noise levels, hardware specifications, and software settings. We applied the UCBI model to assess the uncertainty of purity measurements, and compared the results to those from conventional qualification. We demonstrated that the UBCI model is suitable to dynamically assess method performance characteristics, based on information extracted from individual chromatograms. The model provides an opportunity for streamlining qualification and validation studies by implementing a "live validation" of test results utilizing UBCI as a concurrent assessment of measurement uncertainty. Therefore, UBCI can potentially mitigate the challenges associated with laborious conventional method validation and facilitates the introduction of more advanced analytical technologies during the method lifecycle.

Analysis of persistent current in the superconducting magnets on an EDS Maglev vehicle for high-speed passenger transport

Energy Technology Data Exchange (ETDEWEB)

Azukizawa, Teruo [R and D Center, Toshiba Corp. (Japan)

1996-12-31

In an electrodynamic suspension system using superconducting magnets, an air core system is employed to effectively use strong magnetic fields produced by the superconducting magnets. This paper proposes an analysis method for the fluctuating persistent current in an superconducting soil, considering electromagnetic effects of the conductive cryostat. (HW)

A new approach to control a deflection of an electroplated microstructure: dual current electroplating methods

International Nuclear Information System (INIS)

Yang, Hyun-Ho; Seo, Min-Ho; Han, Chang-Hoon; Yoon, Jun-Bo

2013-01-01

We propose and demonstrate a simple and novel method to control the deflection in a suspended microstructure by using a dual current electroplating (DuCE) method. The key concept of this method is to divide the structure into two layers—a bottom layer and a top layer—and then apply respective current densities in electroplating to those two layers while all other conditions are kept the same. In addition to a flat structure, the direction of structure bending is freely controlled by virtue of the DuCE method. Cantilever Ni beams with a length of 400 µm, which were electroplated by the conventional single current electroplating method, bent downward with a deflection of 3.4 µm. On the contrary, by the DuCE method, cantilever beams with a length of 400 µm showed an almost flat structure as desired. (The current densities of the bottom layer, the top layer, and the ratio of the two current densities, are 0.15, 1.24 A dm −2 , and 8.3, respectively.) Consequently, a nickel electroplated spiral structure with a length of 8600 µm was suspended flat with an end deflection of less than 0.7 µm (the ratio between the deflection and length is 0.007%). This work therefore represents the unprecedented ultra-long suspended microstructure with submicrometer deflection. (paper)

Plasma-current structures of plasma focus during the current disruption

International Nuclear Information System (INIS)

Krokhin, O.N.; Kalachev, N.V.; Malafeev, Yu.S.; Nikulin, V.Ya; Polukhin, S.N.; Tsybenko, S.P.

2000-01-01

The results are presented of an investigation of the plasma structures arising during the current disruption in the Dense Plasma Focus (DPF). The study was performed using the laser-shadow and interferometry methods together with measurements of current and X-ray radiation. An analysis of the experimental results shows that for the construction of a multi mega-amperes current disruption device, the Filippov type of DPF (in comparison with the Mather type) is to be preferred since the processes occurring in the X-ray regime are much faster than in the pinch regime, and this type of plasma focus is geometrically more suitable for the assembly of such a current disrupter.This disrupter is now under construction, based on the 'Tulip' DPF installation

Gravimetric and titrimetric methods of analysis

International Nuclear Information System (INIS)

Rives, R.D.; Bruks, R.R.

1983-01-01

Gravimetric and titrimetric methods of analysis are considered. Methods of complexometric titration are mentioned, as well as methods of increasing sensitivity in titrimetry. Gravimetry and titrimetry are applied during analysis for traces of geological materials

VALUATIONS OF CURRENT METHODS OF RELIGIOUS SLAUGHTER IN ITALY

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B. Catanese

2009-09-01

Full Text Available The aim of this study is to estimate the scale of practices of religious slaughter and to evaluate current methods practiced in Italy. Three different approaches have been used to obtain data. Stunning before sticking is performed in 5,9% of small ruminants slaughtered according to Halal ritual. Hypothesis of violation of Dlgs 333/98 are discussed in the light of an improvement of religious slaughter practices in Italy.

A tutorial review of functional connectivity analysis methods and their interpretational pitfalls

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Andre M Bastos

2016-01-01

Full Text Available Oscillatory neuronal activity may provide a mechanism for dynamic network coordination. Rhythmic neuronal interactions can be quantified using multiple metrics, each with their own advantages and disadvantages. This tutorial will review and summarize current analysis methods used in the field of invasive and non-invasive electrophysiology to study the dynamic connections between neuronal populations. First, we review metrics for functional connectivity, including coherence, phase synchronization, phase-slope index, and Granger causality, with the specific aim to provide an intuition for how these metrics work, as well as their quantitative definition. Next, we highlight a number of interpretational caveats and common pitfalls that can arise when performing functional connectivity analysis, including the common reference problem, the signal to noise ratio problem, the volume conduction problem, the common input problem, and the trial sample size bias problem. These pitfalls will be illustrated by presenting a set of MATLAB-scripts, which can be executed by the reader to simulate each of these potential problems. We discuss of how these issues can be addressed using current methods.

Phytohormone signaling pathway analysis method for comparing hormone responses in plant-pest interactions

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Studham Matthew E

2012-07-01

Full Text Available Abstract Background Phytohormones mediate plant defense responses to pests and pathogens. In particular, the hormones jasmonic acid, ethylene, salicylic acid, and abscisic acid have been shown to dictate and fine-tune defense responses, and identification of the phytohormone components of a particular defense response is commonly used to characterize it. Identification of phytohormone regulation is particularly important in transcriptome analyses. Currently there is no computational tool to determine the relative activity of these hormones that can be applied to transcriptome analyses in soybean. Findings We developed a pathway analysis method that provides a broad measure of the activation or suppression of individual phytohormone pathways based on changes in transcript expression of pathway-related genes. The magnitude and significance of these changes are used to determine a pathway score for a phytohormone for a given comparison in a microarray experiment. Scores for individual hormones can then be compared to determine the dominant phytohormone in a given defense response. To validate this method, it was applied to publicly available data from previous microarray experiments that studied the response of soybean plants to Asian soybean rust and soybean cyst nematode. The results of the analyses for these experiments agreed with our current understanding of the role of phytohormones in these defense responses. Conclusions This method is useful in providing a broad measure of the relative induction and suppression of soybean phytohormones during a defense response. This method could be used as part of microarray studies that include individual transcript analysis, gene set analysis, and other methods for a comprehensive defense response characterization.

ECOLOGY-ECONOMICAL ASSESSMENT OF NEW RECLAMATION METHOD FOR CURRENTLY WORKING TECHNOGENIC MASSIFS

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Alexey Strizhenok

2017-01-01

Full Text Available One of the most relevant problems of the mining industry is the need to reduce the negative impact of technogenic massifs formed by wastes of extraction and processing of mineral raw materials. This problem has a significant meaning for currently used massifs, because traditional ways of reclamation are not suitable for them. The article describes the results of a scientific study on the development of the most efficient reclamation method for currently used technogenic massifs. Described in detail the main results of the field observations, methods and equipment of laboratory experiments conducted to determine agro-chemical properties of the soil and optimal composition of binder agent. The article also provides ecological and economic assessment of the proposed method of reclamation. The study was conducted on the example of the real technogenic massif, formed by wastes of phosphorus ore processing.

Moyer's method of mixed dentition analysis: a meta-analysis ...

African Journals Online (AJOL)

The applicability of tables derived from the data Moyer used to other ethnic groups has ... This implies that Moyer's method of prediction may have population variations. ... Key Words: meta-analysis, mixed dentition analysis, Moyer's method

A current detection based on an extension of the Prony's method

Energy Technology Data Exchange (ETDEWEB)

Deng, C.; Xia, X.; Gong, F. [Changsha Univ. of Science and Technology, Changsha (China). College of Electrical Engineering

2009-07-01

The Prony method for spectrum estimation was combined with an adaptive frequency tracking and current frequency demultiplication method as a harmonic detection system. An injective active power filter was used for effective harmonic wave management. The automated system includes a digital signal processor and a high-speed interfacing device. An algorithm was developed to consider the slow voltage changes in the power grid as well as potential mutations in current harmonics. Widrow-Hoff's LMS algorithm was used to develop rolling steps for the filter. The method was used to detect harmonic waves with a sampling frequency of 400 Hz. Results of the study showed that the detection method can be used in real time to detect fundamental and first harmonics in electric power grids. 10 refs., 2 tabs., 1 fig.

Current Methods Applied to Biomaterials - Characterization Approaches, Safety Assessment and Biological International Standards.

Science.gov (United States)

Oliveira, Justine P R; Ortiz, H Ivan Melendez; Bucio, Emilio; Alves, Patricia Terra; Lima, Mayara Ingrid Sousa; Goulart, Luiz Ricardo; Mathor, Monica B; Varca, Gustavo H C; Lugao, Ademar B

2018-04-10

Safety and biocompatibility assessment of biomaterials are themes of constant concern as advanced materials enter the market as well as products manufactured by new techniques emerge. Within this context, this review provides an up-to-date approach on current methods for the characterization and safety assessment of biomaterials and biomedical devices from a physicalchemical to a biological perspective, including a description of the alternative methods in accordance with current and established international standards. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Gear wear monitoring by modulation signal bispectrum based on motor current signal analysis

Science.gov (United States)

Zhang, Ruiliang; Gu, Fengshou; Mansaf, Haram; Wang, Tie; Ball, Andrew D.

2017-09-01

Gears are important mechanical components for power transmissions. Tooth wear is one of the most common failure modes, which can present throughout a gear's lifetime. It is significant to accurately monitor gear wear progression in order to take timely predictive maintenances. Motor current signature analysis (MCSA) is an effective and non-intrusive approach which is able to monitor faults from both electrical and mechanical systems. However, little research has been reported in monitoring the gear wear and estimating its severity based on MCSA. This paper presents a novel gear wear monitoring method through a modulation signal bispectrum based motor current signal analysis (MSB-MCSA). For a steady gear transmission, it is inevitable to exist load and speed oscillations due to various errors including wears. These oscillations can induce small modulations in the current signals of the driving motor. MSB is particularly effective in characterising such small modulation signals. Based on these understandings, the monitoring process was implemented based on the current signals from a run-to-failure test of an industrial two stages helical gearbox under a moderate accelerated fatigue process. At the initial operation of the test, MSB analysis results showed that the peak values at the bifrequencies of gear rotations and the power supply can be effective monitoring features for identifying faulty gears and wear severity as they exhibit agreeable changes with gear loads. A monotonically increasing trend established by these features allows a clear indication of the gear wear progression. The dismantle inspection at 477 h of operation, made when one of the monitored features is about 123% higher than its baseline, has found that there are severe scuffing wear marks on a number of tooth surfaces on the driving gear, showing that the gear endures a gradual wear process during its long test operation. Therefore, it is affirmed that the MSB-MSCA approach proposed is reliable

Coupled Electro-Magneto-Mechanical-Acoustic Analysis Method Developed by Using 2D Finite Element Method for Flat Panel Speaker Driven by Magnetostrictive-Material-Based Actuator

Science.gov (United States)

Yoo, Byungjin; Hirata, Katsuhiro; Oonishi, Atsurou

In this study, a coupled analysis method for flat panel speakers driven by giant magnetostrictive material (GMM) based actuator was developed. The sound field produced by a flat panel speaker that is driven by a GMM actuator depends on the vibration of the flat panel, this vibration is a result of magnetostriction property of the GMM. In this case, to predict the sound pressure level (SPL) in the audio-frequency range, it is necessary to take into account not only the magnetostriction property of the GMM but also the effect of eddy current and the vibration characteristics of the actuator and the flat panel. In this paper, a coupled electromagnetic-structural-acoustic analysis method is presented; this method was developed by using the finite element method (FEM). This analysis method is used to predict the performance of a flat panel speaker in the audio-frequency range. The validity of the analysis method is verified by comparing with the measurement results of a prototype speaker.

Chromatographic Methods for the Analysis of Polyphenols in Wines

Directory of Open Access Journals (Sweden)

Medić-Šarić, M.

2009-03-01

Full Text Available Wine is an excellent source of various classes of polyphenols, including phenolic acids, flavonoids, and trihydroxystilbene resveratrol (Fig.1. Polyphenols play a major role in wine quality since they contribute to the sensory characteristics of wine, particularly color and astringency. A recent interest in these substances has been stimulated by abundant evidence of their beneficial effects on human health, such as anticarcinogenic, antiinflamatory and antimicrobial activities. Therefore, numerous studies have been performed in the attempt to analyze polyphenols in wine. This paper reviews the current advances in the determination of polyphenols in wine by the major chromatographic techniques such as thin-layer chromatography (TLC and high-performance liquid chromatography (HPLC.The great complexity of the polyphenolic content of wine and the difficulty in obtaining some of the standards usually require sample preparation before analysis. Two methods for sample preparation, liquid-liquid extraction and solid-phase extraction, are most commonly applied. Hydrolysis is applied frequently, but not exclusively, to remove the sugar moieties from glycosides.TLC on silica gel plates is useful for the rapid and low-cost separation and identification of the polyphenols present in wine (Fig. 2. Densitometric quantitative analysis of polyphenols in wine extracts is usually performed by scanning the TLC plates with UV light at wavelengths of 350–365 nm or 250–260 nm (Fig. 3. For the evaluation of the most efficient mobile phase and an optimal choice of the combination of two or more mobile phases, two methods may be applied: information theory and numerical taxonomy. HPLC currently represents the most popular technique for the analysis of polyphenols in wine. For this purpose, a reversed-phase HPLC method that uses gradient elution with binary elution system is usually employed. Routine detection is based on measurement of UV-Vis absorption with a diode

Risk Assessment Method for Offshore Structure Based on Global Sensitivity Analysis

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Zou Tao

2012-01-01

Full Text Available Based on global sensitivity analysis (GSA, this paper proposes a new risk assessment method for an offshore structure design. This method quantifies all the significances among random variables and their parameters at first. And by comparing the degree of importance, all minor factors would be negligible. Then, the global uncertainty analysis work would be simplified. Global uncertainty analysis (GUA is an effective way to study the complexity and randomness of natural events. Since field measured data and statistical results often have inevitable errors and uncertainties which lead to inaccurate prediction and analysis, the risk in the design stage of offshore structures caused by uncertainties in environmental loads, sea level, and marine corrosion must be taken into account. In this paper, the multivariate compound extreme value distribution model (MCEVD is applied to predict the extreme sea state of wave, current, and wind. The maximum structural stress and deformation of a Jacket platform are analyzed and compared with different design standards. The calculation result sufficiently demonstrates the new risk assessment method’s rationality and security.

Simplified inelastic analysis methods applied to fast breeder reactor core design

International Nuclear Information System (INIS)

Abo-El-Ata, M.M.

1978-01-01

The paper starts with a review of some currently available simplified inelastic analysis methods used in elevated temperature design for evaluating plastic and thermal creep strains. The primary purpose of the paper is to investigate how these simplified methods may be applied to fast breeder reactor core design where neutron irradiation effects are significant. One of the problems discussed is irradiation-induced creep and its effect on shakedown, ratcheting, and plastic cycling. Another problem is the development of swelling-induced stress which is an additional loading mechanism and must be taken into account. In this respect an expression for swelling-induced stress in the presence of irradiation creep is derived and a model for simplifying the stress analysis under these conditions is proposed. As an example, the effects of irradiation creep and swelling induced stress on the analysis of a thin walled tube under constant internal pressure and intermittent heat fluxes, simulating a fuel pin, is presented

Methods for Specific Electrode Resistance Measurement during Transcranial Direct Current Stimulation

Science.gov (United States)

Khadka, Niranjan; Rahman, Asif; Sarantos, Chris; Truong, Dennis Q.; Bikson, Marom

2014-01-01

Background Transcranial Direct Current Stimulation (tDCS) is investigated to treat a wide range of neuropsychiatric disorders, for rehabilitation, and for enhancing cognitive performance. The monitoring of electrode resistance before and during tDCS is considered important for tolerability and safety, where an unusually high resistance is indicative of undesired electrode or poor skin contact conditions. Conventional resistance measurement methods do not isolate individual electrode resistance but rather measures overall voltage. Moreover, for HD-tDCS devices, cross talk across electrodes makes concurrent resistance monitoring unreliable. Objective We propose a novel method for monitoring of the individual electrode resistance during tDCS, using a super-position of direct current with a test-signal (low-intensity and low-frequency sinusoids with electrode– specific frequencies) and a single sentinel electrode (not used for DC). Methods To validate this methodology, we developed lumped-parameter models of two and multi-electrode tDCS. Approaches with and without a sentinel electrode were solved and underlying assumptions identified. Assumptions were tested and parameterized in healthy participants using forearm stimulation combining tDCS (2 mA) and sinusoidal test-signals (38 μA and 76 μA peak to peak at 1 Hz, 10 Hz, and 100 Hz) and an in vitro test (where varied electrode failure modes were created). DC and AC component voltages across the electrodes were compared and participants were asked to rate subjective pain. Results A sentinel electrode is required to isolate electrode resistance in a two-electrode tDCS system. For multi-electrode resistance tracking, cross talk was aggravated with electrode proximity and current/resistance mismatches, but could be corrected using proposed approaches. Average voltage and average pain scores were not significantly different across test current intensities and frequencies (two-way repeated measures ANOVA) indicating the

Micromagnetic analysis of geometrically controlled current-driven magnetization switching

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O. Alejos

2017-05-01

Full Text Available The magnetization dynamics induced by current pulses in a pair of two “S-shaped” ferromagnetic elements, each one consisting on two oppositely tilted tapered spikes at the ends of a straight section, is theoretically studied by means of micromagnetic simulations. Our results indicate that the magnetization reversal is triggered by thermal activation, which assists the current-induced domain nucleation and the propagation of domain walls. The detailed analysis of the magnetization dynamics reveals that the magnetization switching is only achieved when a single domain wall is nucleated in the correct corner of the element. In agreement with recent experimental studies, the switching is purely dictated by the shape, being independent of the current polarity. The statistical study points out that successful switching is only achieved within a narrow range of the current pulse amplitudes.

Use of the discourse analysis method to study current political practice (by the example of representation of the political leader image

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Frolova Nadezhda

2016-01-01

Full Text Available The potentialities in the application of the discourse analysis method to study a political discourse as a current political practice are shown. The authors, using the Foucault methodology, offer a sociological definition for the political discourse. It is the authors’ opinion that the approach mentioned allows investigating a political discourse as a practice for the formation of a certain reality, specific agents, institutions and organizations. A political discourse is a simulative dynamic model of political area where various subdiscourses interact, thus creating their own ideas of policy, symbols and images. Subdiscourses of political leaders become dominating. Inasmuch as a political discourse in a current political system is carried out with the aid of mass media, it could be considered as a media discourse of policy. The authors consider the representation as a basic mechanism for the formation of a political discourse, by the example of the representation of the image of V.V. Putin, the President of the Russian Federation. The representation of a political leader image in a political discourse has a number of peculiarities. It is carried out on the basis of certain principles with the aid of the system of political codes. Empiric investigations allowed making a conclusion that the main symbolic image for the Russian President is an image of a super-hero. It is the authors’ opinion, the image of V.V. Putin as a leader super-hero is determined by the specificity of the Russian political culture within the limits of which a leader is a center of power establishing an authoritarian style of ruling. The authors show the process of the political legitimacy displacement from the institutional level to the personal one by means of mass media. A political leader gains a status of a subject establishing moral, social and value reference points for the whole of the society.

A Review of Smart House Analysis Methods for Assisting Older People Living Alone

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Veralia Gabriela Sanchez

2017-07-01

Full Text Available Smart Houses are a prominent field of research referring to environments adapted to assist people in their everyday life. Older people and people with disabilities would benefit the most from the use of Smart Houses because they provide the opportunity for them to stay in their home for as long as possible. In this review, the developments achieved in the field of Smart Houses for the last 16 years are described. The concept of Smart Houses, the most used analysis methods, and current challenges in Smart Houses are presented. A brief introduction of the analysis methods is given, and their implementation is also reported.

Advances in exergy analysis: a novel assessment of the Extended Exergy Accounting method

International Nuclear Information System (INIS)

Rocco, M.V.; Colombo, E.; Sciubba, E.

2014-01-01

additional insight in and more relevant information for every comparative analysis of energy conversion systems, both at a global and a local level. In the paper, traditional and advanced exergy analysis methods are briefly discussed and EEA theoretical foundations and details for its application are described in detail. Methods: The method converts not only material and energy flows, but externalities as well (labour, capital and environmental costs) into flows of equivalent primary exergy, so that all exchanges between the system and the environment can be completely accounted for on a rigorous thermodynamic basis. The current emphasis decision makers and by public opinion alike seem to be placing on sustainability generates the need for continue research in the field of systems analysis, and a preliminary review confirms that exergy may constitute a coherent and rational basis for developing global and local analysis methods. Moreover, extended exergy accounting possesses some specific and peculiar characteristics that make it more suitable for life-cycle and cradle-to-grave (or well-to-wheel) applications. Results: Taxonomy for the classification of exergy-based methods is proposed. A novel assessment of the EEA method is provided, its advantages and drawbacks are discussed and areas in need of further theoretical investigation are identified. Conclusions: Since EEA is a life-cycle method, it is argued that it represents an improvement with regard to other current methods, in that it provides additional insight into the phenomenological aspects of any “energy conversion chain”. The paper demonstrates that the Extended Exergy cost function can be used within the traditional and very well formalized Thermoeconomic framework, replacing the economic cost function in order to evaluate and optimize the consumption of resources of a system in a more complete and rational way. Practical implications: This paper contains some specific proposals as to the further development

Determination of vitamin C in foods: current state of method validation.

Science.gov (United States)

Spínola, Vítor; Llorent-Martínez, Eulogio J; Castilho, Paula C

2014-11-21

Vitamin C is one of the most important vitamins, so reliable information about its content in foodstuffs is a concern to both consumers and quality control agencies. However, the heterogeneity of food matrixes and the potential degradation of this vitamin during its analysis create enormous challenges. This review addresses the development and validation of high-performance liquid chromatography methods for vitamin C analysis in food commodities, during the period 2000-2014. The main characteristics of vitamin C are mentioned, along with the strategies adopted by most authors during sample preparation (freezing and acidification) to avoid vitamin oxidation. After that, the advantages and handicaps of different analytical methods are discussed. Finally, the main aspects concerning method validation for vitamin C analysis are critically discussed. Parameters such as selectivity, linearity, limit of quantification, and accuracy were studied by most authors. Recovery experiments during accuracy evaluation were in general satisfactory, with usual values between 81 and 109%. However, few methods considered vitamin C stability during the analytical process, and the study of the precision was not always clear or complete. Potential future improvements regarding proper method validation are indicated to conclude this review. Copyright © 2014. Published by Elsevier B.V.

Computer circuit analysis of induced currents in the MFTF-B magnet system

International Nuclear Information System (INIS)

Magnuson, G.D.; Woods, E.L.

1981-01-01

An analysis was made of the induced current behavior of the MFTF-B magnet system. Although the magnet system consists of 22 coils, because of its symmetry we considered only 11 coils in the analysis. Various combinations of the coils were dumped either singly or in groups, with the current behavior in all magnets calculated as a function of time after initiation of the dump

Condition-based fault tree analysis (CBFTA): A new method for improved fault tree analysis (FTA), reliability and safety calculations

International Nuclear Information System (INIS)

Shalev, Dan M.; Tiran, Joseph

2007-01-01

Condition-based maintenance methods have changed systems reliability in general and individual systems in particular. Yet, this change does not affect system reliability analysis. System fault tree analysis (FTA) is performed during the design phase. It uses components failure rates derived from available sources as handbooks, etc. Condition-based fault tree analysis (CBFTA) starts with the known FTA. Condition monitoring (CM) methods applied to systems (e.g. vibration analysis, oil analysis, electric current analysis, bearing CM, electric motor CM, and so forth) are used to determine updated failure rate values of sensitive components. The CBFTA method accepts updated failure rates and applies them to the FTA. The CBFTA recalculates periodically the top event (TE) failure rate (λ TE ) thus determining the probability of system failure and the probability of successful system operation-i.e. the system's reliability. FTA is a tool for enhancing system reliability during the design stages. But, it has disadvantages, mainly it does not relate to a specific system undergoing maintenance. CBFTA is tool for updating reliability values of a specific system and for calculating the residual life according to the system's monitored conditions. Using CBFTA, the original FTA is ameliorated to a practical tool for use during the system's field life phase, not just during system design phase. This paper describes the CBFTA method and its advantages are demonstrated by an example

Statistical Analysis of the labor Market in Ukraine Using Multidimensional Classification Methods: the Regional Aspect

Directory of Open Access Journals (Sweden)

Korepanov Oleksiy S.

2017-12-01

Full Text Available The aim of the article is to study the labor market in Ukraine in the regional context using cluster analysis methods. The current state of the labor market in regions of Ukraine is analyzed, and a system of statistical indicators that influence the state and development of this market is formed. The expediency of using cluster analysis for grouping regions according to the level of development of the labor market is substantiated. The essence of cluster analysis is revealed, its main goal, key tasks, which can be solved by means of such analysis, are presented, basic stages of the analysis are considered. The main methods of clustering are described and, based on the results of the simulation, the advantages and disadvantages of each method are justified. In the work the clustering of regions of Ukraine by the level of labor market development using different methods of cluster analysis is carried out, conclusions on the results of the calculations performed are presented, and the main directions for further research are outlined.

Seismic design and analysis methods

International Nuclear Information System (INIS)

Varpasuo, P.

1993-01-01

Seismic load is in many areas of the world the most important loading situation from the point of view of structural strength. Taking this into account it is understandable, that there has been a strong allocation of resources in the seismic analysis during the past ten years. In this study there are three areas of the center of gravity: (1) Random vibrations; (2) Soil-structure interaction and (3) The methods for determining structural response. The solution of random vibration problems is clarified with the aid of applications in this study and from the point of view of mathematical treatment and mathematical formulations it is deemed sufficient to give the relevant sources. In the soil-structure interaction analysis the focus has been the significance of frequency dependent impedance functions. As a result it was obtained, that the description of the soil with the aid of frequency dependent impedance functions decreases the structural response and it is thus always the preferred method when compared to more conservative analysis types. From the methods to determine the C structural response the following four were tested: (1) The time history method; (2) The complex frequency-response method; (3) Response spectrum method and (4) The equivalent static force method. The time history appeared to be the most accurate method and the complex frequency-response method did have the widest area of application. (orig.). (14 refs., 35 figs.)

Spectrochemical analysis of plutonium using direct current plasma emission spectrometry

International Nuclear Information System (INIS)

Morris, W.F.; Fadeff, S.K.; Torres, S.

1983-01-01

One year ago, LLNL was just completing the installation of a Direct Current Plasma (DCP) spectrometer for the analysis of Pu and Pu alloys. The installation was completed in December 1982 and has been utilized regularly for Pu analysis since then. This paper discusses the experience with the instrument and some data demonstrating its performance

Quantitative Risk Analysis: Method And Process

Directory of Open Access Journals (Sweden)

Anass BAYAGA

2010-03-01

Full Text Available Recent and past studies (King III report, 2009: 73-75; Stoney 2007;Committee of Sponsoring Organisation-COSO, 2004, Bartell, 2003; Liebenberg and Hoyt, 2003; Reason, 2000; Markowitz 1957 lament that although, the introduction of quantifying risk to enhance degree of objectivity in finance for instance was quite parallel to its development in the manufacturing industry, it is not the same in Higher Education Institution (HEI. In this regard, the objective of the paper was to demonstrate the methods and process of Quantitative Risk Analysis (QRA through likelihood of occurrence of risk (phase I. This paper serves as first of a two-phased study, which sampled hundred (100 risk analysts in a University in the greater Eastern Cape Province of South Africa.The analysis of likelihood of occurrence of risk by logistic regression and percentages were conducted to investigate whether there were a significant difference or not between groups (analyst in respect of QRA.The Hosmer and Lemeshow test was non-significant with a chi-square(X2 =8.181; p = 0.300, which indicated that there was a good model fit, since the data did not significantly deviate from the model. The study concluded that to derive an overall likelihood rating that indicated the probability that a potential risk may be exercised within the construct of an associated threat environment, the following governing factors must be considered: (1 threat source motivation and capability (2 nature of the vulnerability (3 existence and effectiveness of current controls (methods and process.

Analysis of Precision of Activation Analysis Method

DEFF Research Database (Denmark)

Heydorn, Kaj; Nørgaard, K.

1973-01-01

The precision of an activation-analysis method prescribes the estimation of the precision of a single analytical result. The adequacy of these estimates to account for the observed variation between duplicate results from the analysis of different samples and materials, is tested by the statistic T...

A probabilistic method for the estimation of ocean surface currents from short time series of HF radar data

Science.gov (United States)

Guérin, Charles-Antoine; Grilli, Stéphan T.

2018-01-01

We present a new method for inverting ocean surface currents from beam-forming HF radar data. In contrast with the classical method, which inverts radial currents based on shifts of the main Bragg line in the radar Doppler spectrum, the method works in the temporal domain and inverts currents from the amplitude modulation of the I and Q radar time series. Based on this principle, we propose a Maximum Likelihood approach, which can be combined with a Bayesian inference method assuming a prior current distribution, to infer values of the radial surface currents. We assess the method performance by using synthetic radar signal as well as field data, and systematically comparing results with those of the Doppler method. The new method is found advantageous for its robustness to noise at long range, its ability to accommodate shorter time series, and the possibility to use a priori information to improve the estimates. Limitations are related to current sign errors at far-ranges and biased estimates for small current values and very short samples. We apply the new technique to a data set from a typical 13.5 MHz WERA radar, acquired off of Vancouver Island, BC, and show that it can potentially improve standard synoptic current mapping.

Vacuum Large Current Parallel Transfer Numerical Analysis

Directory of Open Access Journals (Sweden)

Enyuan Dong

2014-01-01

Full Text Available The stable operation and reliable breaking of large generator current are a difficult problem in power system. It can be solved successfully by the parallel interrupters and proper timing sequence with phase-control technology, in which the strategy of breaker’s control is decided by the time of both the first-opening phase and second-opening phase. The precise transfer current’s model can provide the proper timing sequence to break the generator circuit breaker. By analysis of the transfer current’s experiments and data, the real vacuum arc resistance and precise correctional model in the large transfer current’s process are obtained in this paper. The transfer time calculated by the correctional model of transfer current is very close to the actual transfer time. It can provide guidance for planning proper timing sequence and breaking the vacuum generator circuit breaker with the parallel interrupters.

Petroleum Pumps’ Current and Vibration Signatures Analysis Using Wavelet Coherence Technique

Directory of Open Access Journals (Sweden)

Rmdan Shnibha

2013-01-01

Full Text Available Vibration analysis is widely used for rotating machinery diagnostics; however measuring vibration of operational oil well pumps is not possible. The pump’s driver’s current signatures may provide condition-related information without the need for an access to the pump itself. This paper investigates the degree of relationship between the pump’s driver’s current signatures and its induced vibration. This relationship between the driver’s current signatures (DCS and its vibration signatures (DVS is studied by calculating magnitude-squared coherence and phase coherence parameters at a certain frequency band using continuous wavelet transform (CWT. The CWT coherence-based technique allows better analysis of temporal evolution of the frequency content of dynamic signals and areas in the time-frequency plane where the two signals exhibit common power or consistent phase behaviour indicating a relationship between the signals. This novel approach is validated by experimental data acquired from 3 kW petroleum pump’s driver. Both vibration and current signatures were acquired under different speed and load conditions. The outcomes of this research suggest the use of DCS analysis as reliable and inexpensive condition monitoring tool, which could be implemented for oil pumps, real-time monitoring associated with condition-based maintenance (CBM program.

Current and Current Fluctuations in Quantum Shuttles

DEFF Research Database (Denmark)

Jauho, Antti-Pekka; Flindt, Christian; Novotny, Tomas

2005-01-01

theoretical tools needed for the analysis, e.g., generalized master equations and Wigner functions, and we outline the methods how the resulting large numerical problems can be handled. Illustrative results are given for current, noise, and full counting statistics for a number of model systems. Throughout...... the review we focus on the physics behind the various approximations, and some simple examples are given to illustrate the theoretical concepts. We also comment on the experimental situation. ©2005 American Institute of Physics...

Trial Sequential Methods for Meta-Analysis

Science.gov (United States)

Kulinskaya, Elena; Wood, John

2014-01-01

Statistical methods for sequential meta-analysis have applications also for the design of new trials. Existing methods are based on group sequential methods developed for single trials and start with the calculation of a required information size. This works satisfactorily within the framework of fixed effects meta-analysis, but conceptual…

Analysis of electric current flow through the HTc multilayered superconductors

Science.gov (United States)

Sosnowski, J.

2016-02-01

Issue of the flow of the transport current through multilayered high-temperature superconductors is considered, depending on the direction of the electric current towards the surface of the superconducting CuO2 layers. For configuration of the current flow inside of the layers and for perpendicular magnetic field, it will be considered the current limitations connected with interaction of pancake type vortices with nano-sized defects, created among other during fast neutrons irradiation. So it makes this issue associated with work of nuclear energy devices, like tokamak ITER, LHC and actually developed accelerator Nuclotron-NICA, as well as cryocables. Phenomenological analysis of the pinning potential barrier formation will be in the paper given, which determines critical current flow inside the plane. Comparison of theoretical model with experimental data will be presented too as well as influence of fast neutrons irradiation dose on critical current calculated. For current direction perpendicular to superconducting planes the current-voltage characteristics are calculated basing on model assuming formation of long intrinsic Josephson's junctions in layered HTc superconductors.

Evaluation of plate type fuel elements by eddy current test method

International Nuclear Information System (INIS)

Frade, Rangel Teixeira

2015-01-01

Plate type fuel elements are used in MTR research nuclear reactors. The fuel plates are manufactured by assembling a briquette containing the fissile material inserted in a frame, with metal plates in both sides of the set, to act as a cladding. This set is rolled under controlled conditions in order to obtain the fuel plate. In Brazil, this type of fuel is manufactured by IPEN and used in the IEA-R1 reactor. After fabrication of three batches of fuel plates, 24 plates, one of them is taken, in order to verify the thickness of the cladding. For this purpose, the plate is sectioned and the thickness measurements are carried out by using optical microscopy. This procedure implies in damage of the plate, with the consequent cost. Besides, the process of sample preparation for optical microscopy analysis is time consuming, it is necessary an infrastructure for handling radioactive materials and there is a generation of radioactive residues during the process. The objective of this study was verify the applicability of eddy current test method for nondestructive measurement of cladding thickness in plate type nuclear fuels, enabling the inspection of all manufactured fuel plates. For this purpose, reference standards, representative of the cladding of the fuel plates, were manufactured using thermomechanical processing conditions similar to those used for plates manufacturing. Due to no availability of fuel plates for performing the experiments, the presence of the plate’s core was simulated using materials with different electrical conductivities, fixed to the thickness reference standards. Probes of eddy current testing were designed and manufactured. They showed high sensitivity to thickness variations, being able to separate small thickness changes. The sensitivity was higher in tests performed on the reference standards and samples without the presence of the materials simulating the core. For examination of the cladding with influence of materials simulating the

Harmonic currents circulation in electrical networks simulation and analysis

Energy Technology Data Exchange (ETDEWEB)

Em-Mamlouk, W.M. [MEP, Cairo (Egypt); El-Sharkawy, M.A. [Shams Univ., Cairo (Egypt). Dept. of Electrical Power and Machines; Mostafa, H.E. [Jazan Univ., Jazan (Saudi Arabia). Electrical Dept.

2009-07-01

A detailed harmonic flow analysis for a 13-bus balanced industrial distribution system was presented. The aim of the study was to determine the influence of harmonic sources in various branches of the system on voltage and current waveforms before disruptions to the utility supply system occurred. The current harmonic contents of an adjustable speed drive (ASD) were studied under various loading conditions. The test system was simulated using a standard study test system. Harmonic effects from multiple sources were investigated, and voltage distortion on the different buses was monitored. The study demonstrated that while the harmonic loads circulated harmonic currents in all system branches, no harmonic source was directly connected to the system buses. Many of the investigated cases exceeded allowable voltage total harmonic distortion and or current total harmonic distortion standards set by the Institute of Electrical and Electronic Engineers (IEEE). It was concluded that active harmonic filters should be used to prevent the effects of harmonic current circulation at different buses on neighbouring loads within a system. 8 refs., 11 tabs., 15 figs.

Constant current coulometric method for the determination of uranium in active process solutions

International Nuclear Information System (INIS)

Chitnis, R.T.; Talnikar, S.G.; Paranjape, A.H.

1980-01-01

The determination of uranium in the range of 2.5-5 mg by constant current coulometry is described. The procedure is based on the modified version of the DAVIES - GRAY method, wherein uranium, after the reduction step, is oxidized by adding a known amount of potassium dichromate, and the excess of dichromate is determined by titration with Fe 2+ solution. Fe 2+ ions needed for the titration are generated in situ with 100% current efficiency by electrolytic reduction of Fe 3+ . The method is found to be accurate with a coefficient of variation better than 0.2%. (author)

Design and analysis of group-randomized trials in cancer: A review of current practices.

Science.gov (United States)

Murray, David M; Pals, Sherri L; George, Stephanie M; Kuzmichev, Andrey; Lai, Gabriel Y; Lee, Jocelyn A; Myles, Ranell L; Nelson, Shakira M

2018-06-01

The purpose of this paper is to summarize current practices for the design and analysis of group-randomized trials involving cancer-related risk factors or outcomes and to offer recommendations to improve future trials. We searched for group-randomized trials involving cancer-related risk factors or outcomes that were published or online in peer-reviewed journals in 2011-15. During 2016-17, in Bethesda MD, we reviewed 123 articles from 76 journals to characterize their design and their methods for sample size estimation and data analysis. Only 66 (53.7%) of the articles reported appropriate methods for sample size estimation. Only 63 (51.2%) reported exclusively appropriate methods for analysis. These findings suggest that many investigators do not adequately attend to the methodological challenges inherent in group-randomized trials. These practices can lead to underpowered studies, to an inflated type 1 error rate, and to inferences that mislead readers. Investigators should work with biostatisticians or other methodologists familiar with these issues. Funders and editors should ensure careful methodological review of applications and manuscripts. Reviewers should ensure that studies are properly planned and analyzed. These steps are needed to improve the rigor and reproducibility of group-randomized trials. The Office of Disease Prevention (ODP) at the National Institutes of Health (NIH) has taken several steps to address these issues. ODP offers an online course on the design and analysis of group-randomized trials. ODP is working to increase the number of methodologists who serve on grant review panels. ODP has developed standard language for the Application Guide and the Review Criteria to draw investigators' attention to these issues. Finally, ODP has created a new Research Methods Resources website to help investigators, reviewers, and NIH staff better understand these issues. Published by Elsevier Inc.

Method for confining the magnetic field of the cross-tail current inside the magnetopause

Science.gov (United States)

Sotirelis, T.; Tsyganenko, N. A.; Stern, D. P.

1994-01-01

A method is presented for analytically representing the magnetic field due to the cross-tail current and its closure on the magnetopause. It is an extension of a method used by Tsyganenko (1989b) to confine the dipole field inside an ellipsoidal magnetopause using a scalar potential. Given a model of the cross-tail current, the implied net magnetic field is obtained by adding to the cross-tail current field a potential field B = - del gamma, which makes all field lines divide into two disjoint groups, separated by the magnetopause (i.e., the combined field is made to have zero normal component with the magnetopause). The magnetopause is assumed to be an ellipsoid of revolution (a prolate spheroid) as an approximation to observations (Sibeck et al., 1991). This assumption permits the potential gamma to be expressed in spheroidal coordinates, expanded in spheroidal harmonics and its terms evaluated by performing inversion integrals. Finally, the field outside the magnetopause is replaced by zero, resulting in a consistent current closure along the magnetopause. This procedure can also be used to confine the modeled field of any other interior magnetic source, though the model current must always flow in closed circuits. The method is demonstrated on the T87 cross-tail current, examples illustrate the effect of changing the size and shape of the prescribed magnetopause and a comparison is made to an independent numerical scheme based on the Biot-Savart equation.

A Control Method of Current Type Matrix Converter for Plasma Control Coil Power Supply

International Nuclear Information System (INIS)

Shimada, K.; Matsukawa, M.; Kurihara, K.; Jun-ichi Itoh

2006-01-01

In exploration to a tokamak fusion reactor, the control of plasma instabilities of high β plasma such as neoclassical tearing mode (NTM), resistive wall mode (RWM) etc., is the key issue for steady-state sustainment. One of the proposed methods to avoid suppressing RWM is that AC current having a phase to work for reduction the RWM growth is generated in a coil (sector coil) equipped spirally on the plasma vacuum vessel. To stabilize RWM, precise and fast real-time feedback control of magnetic field with proper amplitude and frequency is necessary. This implies that an appropriate power supply dedicated for such an application is expected to be developed. A matrix converter as one of power supply candidates for this purpose could provide a solution The matrix converter, categorized in an AC/AC direct converter composed of nine bi-directional current switches, has a great feature that a large energy storage element is unnecessary in comparison with a standard existing AC/AC indirect converter, which is composed of an AC/DC converter and a DC/AC inverter. It is also advantageous in cost and size of its applications. Fortunately, a voltage type matrix converter has come to be available at the market recently, while a current type matrix converter, which is advantageous for fast control of the large-inductance coil current, has been unavailable. On the background above mentioned, we proposed a new current type matrix converter and its control method applicable to a power supply with fast response for suppressing plasma instabilities. Since this converter is required with high accuracy control, the gate control method is adopted to three-phase switching method using middle phase to reduce voltage and current waveforms distortion. The control system is composed of VME-bus board with DSP (Digital Signal Processor) and FPGA (Field Programmable Gate Array) for high speed calculation and control. This paper describes the control method of a current type matrix converter

The surface analysis methods; Les methodes d`analyse des surfaces

Energy Technology Data Exchange (ETDEWEB)

Deville, J.P. [Institut de Physique et Chimie, 67 - Strasbourg (France)

1998-11-01

Nowadays, there are a lot of surfaces analysis methods, each having its specificity, its qualities, its constraints (for instance vacuum) and its limits. Expensive in time and in investment, these methods have to be used deliberately. This article appeals to non specialists. It gives some elements of choice according to the studied information, the sensitivity, the use constraints or the answer to a precise question. After having recalled the fundamental principles which govern these analysis methods, based on the interaction between radiations (ultraviolet, X) or particles (ions, electrons) with matter, two methods will be more particularly described: the Auger electron spectroscopy (AES) and x-rays photoemission spectroscopy (ESCA or XPS). Indeed, they are the most widespread methods in laboratories, the easier for use and probably the most productive for the analysis of surface of industrial materials or samples submitted to treatments in aggressive media. (O.M.) 11 refs.

Ceramic tape casting: A review of current methods and trends with emphasis on rheological behaviour and flow analysis

International Nuclear Information System (INIS)

Jabbari, M.; Bulatova, R.; Tok, A.I.Y.; Bahl, C.R.H.; Mitsoulis, E.; Hattel, J.H.

2016-01-01

Highlights: • Brief review of the tape casting process for ceramics. • Role of fluid flow analysis in tape casting of ceramics. • Rheological classification of common fluids in tape casting. • Review of commonly used rheological behaviour for ceramics in tape casting. - Abstract: Tape casting has been used to produce thin layers of ceramics that can be used as single layers or can be stacked and laminated into multilayered structures. Today, tape casting is the basic fabrication process that provides multilayered capacitors and multilayered ceramic packages. In tape casting the rheological behaviour of the slurry as well as the material flow during casting are of utmost importance since these phenomena to a large extent determine the final properties and hence the quality of the cast product. During the last decades this has led to an increasing number of works in literature within fluid flow analysis of tape casting. In the present paper a review of the development of the tape casting process with particular focus on the rheological classifications as well as modelling the material flow is hence presented and in this context the current status is examined and future potential discussed.

Ceramic tape casting: A review of current methods and trends with emphasis on rheological behaviour and flow analysis

Energy Technology Data Exchange (ETDEWEB)

Jabbari, M., E-mail: mjab@mek.dtu.dk [Process Modelling Group, Department of Mechanical Engineering, Technical University of Denmark, Nils Koppels Allé, 2800 Kgs. Lyngby (Denmark); Bulatova, R. [Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, Building 779, Roskilde (Denmark); Tok, A.I.Y. [School of Materials Science & Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Bahl, C.R.H. [Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, Building 779, Roskilde (Denmark); Mitsoulis, E. [School of Mining Engineering and Metallurgy, National Technical University of Athens, Zografou, 15780 Athens (Greece); Hattel, J.H. [Process Modelling Group, Department of Mechanical Engineering, Technical University of Denmark, Nils Koppels Allé, 2800 Kgs. Lyngby (Denmark)

2016-10-15

Highlights: • Brief review of the tape casting process for ceramics. • Role of fluid flow analysis in tape casting of ceramics. • Rheological classification of common fluids in tape casting. • Review of commonly used rheological behaviour for ceramics in tape casting. - Abstract: Tape casting has been used to produce thin layers of ceramics that can be used as single layers or can be stacked and laminated into multilayered structures. Today, tape casting is the basic fabrication process that provides multilayered capacitors and multilayered ceramic packages. In tape casting the rheological behaviour of the slurry as well as the material flow during casting are of utmost importance since these phenomena to a large extent determine the final properties and hence the quality of the cast product. During the last decades this has led to an increasing number of works in literature within fluid flow analysis of tape casting. In the present paper a review of the development of the tape casting process with particular focus on the rheological classifications as well as modelling the material flow is hence presented and in this context the current status is examined and future potential discussed.

The Use of Object-Oriented Analysis Methods in Surety Analysis

Energy Technology Data Exchange (ETDEWEB)

Craft, Richard L.; Funkhouser, Donald R.; Wyss, Gregory D.

1999-05-01

Object-oriented analysis methods have been used in the computer science arena for a number of years to model the behavior of computer-based systems. This report documents how such methods can be applied to surety analysis. By embodying the causality and behavior of a system in a common object-oriented analysis model, surety analysts can make the assumptions that underlie their models explicit and thus better communicate with system designers. Furthermore, given minor extensions to traditional object-oriented analysis methods, it is possible to automatically derive a wide variety of traditional risk and reliability analysis methods from a single common object model. Automatic model extraction helps ensure consistency among analyses and enables the surety analyst to examine a system from a wider variety of viewpoints in a shorter period of time. Thus it provides a deeper understanding of a system's behaviors and surety requirements. This report documents the underlying philosophy behind the common object model representation, the methods by which such common object models can be constructed, and the rules required to interrogate the common object model for derivation of traditional risk and reliability analysis models. The methodology is demonstrated in an extensive example problem.

An application of the eddy-current method for inspections of austenitic cladding

International Nuclear Information System (INIS)

Kubis, S.; Herka, M.; Krajcovic, R.

1999-01-01

The application of the eddy-current method for inspections of austenitic cladding by means of pancake probes. Phase and amplitude characteristics of artificial defects and anticipated interference signals. Optimization of inspection parameters

Numerical and experimental analysis of eddy currents induced in tokamak machines

International Nuclear Information System (INIS)

Takahashi, T.; Takahashi, G.; Kazawa, Y.; Suzuki, Y.

1977-01-01

This paper deals with eddy current phenomena in Tokamak machines. A numerical method is presented which will permit eddy currents to be calculated. Examples of numerical results and a discussion of the JT-60 are shown. Calculations are checked by measurements in basic models

Impact Analysis of Electrical Current Characteristics in Relay Function for Electrical and Electronic Protection

International Nuclear Information System (INIS)

Syirrazie Che Soh; Harzawadi Hasim

2013-01-01

This paper is to study effect of electrical current on relay reaction, which has coil and switch inside the relay. An analysis on the electrical current will be conducted to determine current limitation for relay activation purpose. The result of analysis showing that current characteristic of relay and applied load will present their affect to the relay function performance. Finding from this result will bring the idea to develop a suitable design circuit for electrical and electronic protection. (author)

Application of pulse spectro- zonal luminescent method for the rapid method of material analysis

International Nuclear Information System (INIS)

Lisitsin, V.M.; Oleshko, V.I.; Yakovlev, A.N.

2004-01-01

Full text: The scope of luminescent methods of the analysis covers enough a big around of substances as the luminescence can be excited in overwhelming majority of nonmetals. Analytical opportunities of luminescent methods can be essentially expanded by use of pulse excitation and registration of spectra of a luminescence with the time resolved methods. The most perspective method is to use pulses of high-current electron beams with the nanosecond duration for excitation from the following reasons: excitation is carried out ionizing, deeply enough by a penetrating radiation; the pulse of radiation has high capacity, up to 10 8 W, but energy no more than 1 J; the pulse of radiation has the nanosecond duration. Electrons with energy in 300-400 keV will penetrate on depth into some tenth shares of mm, i.e. they create volumetric excitation of a sample. Therefore the luminescence raised by an electronic beam has the information about volumetric properties of substance. High density of excitation allow to find out and study the centers (defects) having a small yield of a luminescence, to analyze the weakly luminescent objects. Occurrence of the new effects is possible useful to analyze of materials. There is an opportunity of reception of the information from change of spectral structure of a luminescence during the time after the ending of a pulse of excitation and kinetic characteristics of attenuation of luminescence. The matter is the energy of radiation is absorbed mainly by a matrix, then electronic excitations one is transferred the centers of a luminescence (defects) of a lattice. Therefore during the time after creation electronic excitations the spectrum of a luminescence can repeatedly change, transferring the information on the centers (defects) which are the most effective radiators at present time. Hence, the study of change of spectra of radiation during the time allows providing an additional way of discrimination of the information on the centers of a

Expert system for eddy current signal analysis: non destructive testing of steam generator tubings

International Nuclear Information System (INIS)

Benoist, B.

1991-01-01

Automatic analysis, by computer, of defect signals in steam generator tubes, based on Eddy current multifrequency technique, is must often inefficient due to pilgrim noise. The first step is to use a method that allows us to eleminate the noise: the adaptative interpolation. Thanks to this method, which ensures reliable data on each channel, the analysis can be realised by taking into account the data corresponding to each basic or mixed channel. By correlating these diverse data, we can class the signals according to two types of defects: single defects (symmetrical), multiple defects (several in the same place). The second step is to use an expert system which allows a reliable diagnosis for whatever family the defect belongs to. According to this classification, analysis is continued and results in the characterization of the defect. The expert system has already been developed with the general purpose application expert system shell SUPER, which is briefly described. The knowledge base (SOCRATE) and the specific tools developed for this application are thoroughly described. The first results obtained with signals corresponding to real defects, that have been recorded in different places, are presented and discussed. The expert system is revealed efficient in all the studied cases, even with signals obtained in very noisy environments [fr

Statistical methods for the analysis of a screening test for chronic beryllium disease

Energy Technology Data Exchange (ETDEWEB)

Frome, E.L.; Neubert, R.L. [Oak Ridge National Lab., TN (United States). Mathematical Sciences Section; Smith, M.H.; Littlefield, L.G.; Colyer, S.P. [Oak Ridge Inst. for Science and Education, TN (United States). Medical Sciences Div.

1994-10-01

The lymphocyte proliferation test (LPT) is a noninvasive screening procedure used to identify persons who may have chronic beryllium disease. A practical problem in the analysis of LPT well counts is the occurrence of outlying data values (approximately 7% of the time). A log-linear regression model is used to describe the expected well counts for each set of test conditions. The variance of the well counts is proportional to the square of the expected counts, and two resistant regression methods are used to estimate the parameters of interest. The first approach uses least absolute values (LAV) on the log of the well counts to estimate beryllium stimulation indices (SIs) and the coefficient of variation. The second approach uses a resistant regression version of maximum quasi-likelihood estimation. A major advantage of the resistant regression methods is that it is not necessary to identify and delete outliers. These two new methods for the statistical analysis of the LPT data and the outlier rejection method that is currently being used are applied to 173 LPT assays. The authors strongly recommend the LAV method for routine analysis of the LPT.

Methods for stable recording of short-circuit current in a Na+-transporting epithelium.

Science.gov (United States)

Gondzik, Veronika; Awayda, Mouhamed S

2011-07-01

Epithelial Na(+) transport as measured by a variety of techniques, including the short-circuit current technique, has been described to exhibit a "rundown" phenomenon. This phenomenon manifests as time-dependent decrease of current and resistance and precludes the ability to carry out prolonged experiments aimed at examining the regulation of this transport. We developed methods for prolonged stable recordings of epithelial Na(+) transport using modifications of the short-circuit current technique and commercial Ussing-type chambers. We utilize the polarized MDCK cell line expressing the epithelial Na(+) channel (ENaC) to describe these methods. Briefly, existing commercial chambers were modified to allow continuous flow of Ringer solution and precise control of such flow. Chamber manifolds and associated plumbing were modified to allow precise temperature clamp preventing temperature oscillations. Recording electrodes were modified to eliminate the use of KCl and prevent membrane depolarization from KCl leakage. Solutions utilized standard bicarbonate-based buffers, but all gasses were prehydrated to clamp buffer osmolarity. We demonstrate that these modifications result in measurements of current and resistance that are stable for at least 2 h. We further demonstrate that drifts in osmolarity similar to those obtained before prior to our modifications can lead to a decrease of current and resistance similar to those attributed to rundown.

The essential theory of fast wave current drive with full wave method

International Nuclear Information System (INIS)

Liu Yan; Gong Xueyu; Yang Lei; Yin Chenyan; Yin Lan

2007-01-01

The full wave numerical method is developed for analyzing fast wave current drive in the range of ion cyclotron waves in tokamak plasmas, taking into account finite larmor radius effects and parallel dispersion. the physical model, the dispersion relation on the assumption of Finite Larmor Radius (FLR) effects and the form of full wave be used for computer simulation are developed. All of the work will contribute to further study of fast wave current drive. (authors)

Automatic Condition Monitoring of Industrial Rolling-Element Bearings Using Motor’s Vibration and Current Analysis

Directory of Open Access Journals (Sweden)

Zhenyu Yang

2015-01-01

Full Text Available An automatic condition monitoring for a class of industrial rolling-element bearings is developed based on the vibration as well as stator current analysis. The considered fault scenarios include a single-point defect, multiple-point defects, and a type of distributed defect. Motivated by the potential commercialization, the developed system is promoted mainly using off-the-shelf techniques, that is, the high-frequency resonance technique with envelope detection and the average of short-time Fourier transform. In order to test the flexibility and robustness, the monitoring performance is extensively studied under diverse operating conditions: different sensor locations, motor speeds, loading conditions, and data samples from different time segments. The experimental results showed the powerful capability of vibration analysis in the bearing point defect fault diagnosis. The current analysis also showed a moderate capability in diagnosis of point defect faults depending on the type of fault, severity of the fault, and the operational condition. The temporal feature indicated a feasibility to detect generalized roughness fault. The practical issues, such as deviations of predicted characteristic frequencies, sideband effects, time-average of spectra, and selection of fault index and thresholds, are also discussed. The experimental work shows a huge potential to use some simple methods for successful diagnosis of industrial bearing systems.

Criticality analysis of thermal reactors for two energy groups applying Monte Carlo and neutron Albedo method

International Nuclear Information System (INIS)

Terra, Andre Miguel Barge Pontes Torres

2005-01-01

The Albedo method applied to criticality calculations to nuclear reactors is characterized by following the neutron currents, allowing to make detailed analyses of the physics phenomena about interactions of the neutrons with the core-reflector set, by the determination of the probabilities of reflection, absorption, and transmission. Then, allowing to make detailed appreciations of the variation of the effective neutron multiplication factor, keff. In the present work, motivated for excellent results presented in dissertations applied to thermal reactors and shieldings, was described the methodology to Albedo method for the analysis criticality of thermal reactors by using two energy groups admitting variable core coefficients to each re-entrant current. By using the Monte Carlo KENO IV code was analyzed relation between the total fraction of neutrons absorbed in the core reactor and the fraction of neutrons that never have stayed into the reflector but were absorbed into the core. As parameters of comparison and analysis of the results obtained by the Albedo method were used one dimensional deterministic code ANISN (ANIsotropic SN transport code) and Diffusion method. The keff results determined by the Albedo method, to the type of analyzed reactor, showed excellent agreement. Thus were obtained relative errors of keff values smaller than 0,78% between the Albedo method and code ANISN. In relation to the Diffusion method were obtained errors smaller than 0,35%, showing the effectiveness of the Albedo method applied to criticality analysis. The easiness of application, simplicity and clarity of the Albedo method constitute a valuable instrument to neutronic calculations applied to nonmultiplying and multiplying media. (author)

Text analysis methods, text analysis apparatuses, and articles of manufacture

Science.gov (United States)

Whitney, Paul D; Willse, Alan R; Lopresti, Charles A; White, Amanda M

2014-10-28

Text analysis methods, text analysis apparatuses, and articles of manufacture are described according to some aspects. In one aspect, a text analysis method includes accessing information indicative of data content of a collection of text comprising a plurality of different topics, using a computing device, analyzing the information indicative of the data content, and using results of the analysis, identifying a presence of a new topic in the collection of text.

Optimization in supply chain management, the current state and future directions: A systematic review and bibliometric analysis

Energy Technology Data Exchange (ETDEWEB)

Movahedipour, M.; Yang, M.; Zeng, J.; Wu, X.; Salam, S.

2016-07-01

Purpose: The purpose of this paper is finding the current state of research and identifies high-potential area for future investigation in optimization in supply chain management. Design/methodology/approach: In this paper we present Bibliometric and Network analysis to examine current state research on optimization in supply chain management to identify established and emergent research field for future investigation. The systematic research review which we used in our study have not grasp or assess by other researchers on this topic. Firstly, based on our methodology Bibliometric analysis began by identifying 1610 publications raised from scientific journals, included literatures from 1994 to March of 2016. Secondly, we applied PageRank algorithm in our data for citation analysis to indicate the significance of a publication. Thirdly, the topological decision variables analysis is done based on Louvain method for network data clustering, for this proposes we used the rigorous tools. Finding: Based on our Network analysis result, the optimization in supply chain management research can be divided into four clusters /modules that introduced fundamental skill, knowledge, theory, application and method. Research limitations/implications: We presented some limitation in our research in some fields which could allow new researchers and practitioners conduct the future research to grow up in different dimensions. Practical implications: Practitioners or policy maker usually are not familiar with these type researches so this is why mush of these survey remain in theatrical and conceptual .Future investigation needs to play in practical application domain instead stop merely in opinion. Originality/value: Based on our research, the researchers have more attention to work in conceptual analysis due to other fields but we believe that in facility location problem there many remarkable rooms still exist for future research to development. We also contributed more details in

Optimization in supply chain management, the current state and future directions: A systematic review and bibliometric analysis

Directory of Open Access Journals (Sweden)

Mahmood Movahedipour

2016-11-01

Full Text Available Purpose: The purpose of this paper is finding the current state of research and identifies high-potential area for future investigation in optimization in supply chain management. Design/methodology/approach: In this paper we present Bibliometric and Network analysis to examine current state research on optimization in supply chain management to identify established and emergent research field for future investigation. The systematic research review which we used in our study have not grasp or assess by other researchers on this topic. Firstly, based on our methodology Bibliometric analysis began by identifying 1610 publications raised from scientific journals, included literatures from 1994 to March of 2016. Secondly, we applied PageRank algorithm in our data for citation analysis to indicate the significance of a publication. Thirdly, the topological decision variables analysis is done based on Louvain method for network data clustering, for this proposes we used the rigorous tools. Finding: Based on our Network analysis result, the optimization in supply chain management research can be divided into four clusters /modules that introduced fundamental skill, knowledge, theory, application and method. Research limitations/implications: We presented some limitation in our research in some fields which could allow new researchers and practitioners conduct the future research to grow up in different dimensions. Practical implications: Practitioners or policy maker usually are not familiar with these type researches so this is why mush of these survey remain in theatrical and conceptual .Future investigation needs to play in practical application  domain instead stop merely in opinion.    Originality/value: Based on our research, the researchers have more attention to work in conceptual analysis due to other fields but we believe that in facility location problem there many remarkable rooms still exist for future research to development

Optimization in supply chain management, the current state and future directions: A systematic review and bibliometric analysis

International Nuclear Information System (INIS)

Movahedipour, M.; Yang, M.; Zeng, J.; Wu, X.; Salam, S.

2016-01-01

Purpose: The purpose of this paper is finding the current state of research and identifies high-potential area for future investigation in optimization in supply chain management. Design/methodology/approach: In this paper we present Bibliometric and Network analysis to examine current state research on optimization in supply chain management to identify established and emergent research field for future investigation. The systematic research review which we used in our study have not grasp or assess by other researchers on this topic. Firstly, based on our methodology Bibliometric analysis began by identifying 1610 publications raised from scientific journals, included literatures from 1994 to March of 2016. Secondly, we applied PageRank algorithm in our data for citation analysis to indicate the significance of a publication. Thirdly, the topological decision variables analysis is done based on Louvain method for network data clustering, for this proposes we used the rigorous tools. Finding: Based on our Network analysis result, the optimization in supply chain management research can be divided into four clusters /modules that introduced fundamental skill, knowledge, theory, application and method. Research limitations/implications: We presented some limitation in our research in some fields which could allow new researchers and practitioners conduct the future research to grow up in different dimensions. Practical implications: Practitioners or policy maker usually are not familiar with these type researches so this is why mush of these survey remain in theatrical and conceptual .Future investigation needs to play in practical application domain instead stop merely in opinion. Originality/value: Based on our research, the researchers have more attention to work in conceptual analysis due to other fields but we believe that in facility location problem there many remarkable rooms still exist for future research to development. We also contributed more details in

A novel method of flat YBCO rings development for shield-type superconducting fault current limiters fabrication

International Nuclear Information System (INIS)

Hekmati, Arsalan; Hosseini, Mehdi; Vakilian, Mehdi; Fardmanesh, Mehdi

2012-01-01

A method has been proposed for flat YBCO ring Fabrication. A prototype SFCL with proposed design has been fabricated using the rings. J c characteristics of the rings are measured using an innovative method. The application of flat superconductor rings has been investigated in the structure of inductive shield-type high temperature superconducting fault current limiters, HT c -SFCL. A laboratory scale inductive shield-type HT c -SFCL has been designed and fabricated using flat superconductor rings. The fabrication process has been fully presented. YBCO powder has been used for the fabrication of superconductor rings. This fabrication process, being quite innovative, is introduced completely. The method of the trapped field measurement has been used for the critical current density measurement of the fabricated superconductor rings. The device with nominal current of 2 A was tested in a 30 V circuit. The SFCL successfully limited the fault currents of up to 10 times the nominal current to an approximately fixed value of 3 A. The voltage-current characteristic of the fabricated prototype has also been obtained and has shown compatibility with the fault current limitation results.

Excitation methods for energy dispersive analysis

International Nuclear Information System (INIS)

Jaklevic, J.M.

1976-01-01

The rapid development in recent years of energy dispersive x-ray fluorescence analysis has been based primarily on improvements in semiconductor detector x-ray spectrometers. However, the whole analysis system performance is critically dependent on the availability of optimum methods of excitation for the characteristic x rays in specimens. A number of analysis facilities based on various methods of excitation have been developed over the past few years. A discussion is given of the features of various excitation methods including charged particles, monochromatic photons, and broad-energy band photons. The effects of the excitation method on background and sensitivity are discussed from both theoretical and experimental viewpoints. Recent developments such as pulsed excitation and polarized photons are also discussed

Improvement of ISI techniques by multi-frequency eddy current testing method for steam generator tube in PWR plant

International Nuclear Information System (INIS)

Endo, Takashi; Kamimura, Takeo; Nishihara, Masatoshi; Araki, Yasuo; Fukui, Shigetaka.

1982-05-01

Eddy current flaw detection techniques are applied to the in-service inspection (ISI) of steam generator tubes in pressurized water reactors (PWR) plant. To improve the reliability and operating efficiency of the plants, efforts are being made to develop eddy current testing methods of various kinds. Multi-frequency eddy current testing method, one of new method, has recently been applied to actual heat exchanger tubes, contributing to the improvement of the detectability and signal evaluation of the ISI. The outline of multi-frequency eddy current testing method and its effects on the improvement of flaw detecting and signal evaluation accuracy are described. (author)

Study on model current predictive control method of PV grid- connected inverters systems with voltage sag

Science.gov (United States)

Jin, N.; Yang, F.; Shang, S. Y.; Tao, T.; Liu, J. S.

2016-08-01

According to the limitations of the LVRT technology of traditional photovoltaic inverter existed, this paper proposes a low voltage ride through (LVRT) control method based on model current predictive control (MCPC). This method can effectively improve the photovoltaic inverter output characteristics and response speed. The MCPC method of photovoltaic grid-connected inverter designed, the sum of the absolute value of the predictive current and the given current error is adopted as the cost function with the model predictive control method. According to the MCPC, the optimal space voltage vector is selected. Photovoltaic inverter has achieved automatically switches of priority active or reactive power control of two control modes according to the different operating states, which effectively improve the inverter capability of LVRT. The simulation and experimental results proves that the proposed method is correct and effective.

An Investigation of the Variety and Complexity of Statistical Methods Used in Current Internal Medicine Literature.

Science.gov (United States)

Narayanan, Roshni; Nugent, Rebecca; Nugent, Kenneth

2015-10-01

. These papers used 128 statistical terms and context-defined concepts, including some from data analysis (56), epidemiology-biostatistics (31), modeling (24), data collection (12), and meta-analysis (5). Ten different software programs were used in these articles. Based on usual undergraduate and graduate statistics curricula, 64.3% of the concepts and methods used in these papers required at least a master's degree-level statistics education. The interpretation of the current medical literature can require an extensive background in statistical methods at an education level exceeding the material and resources provided to most medical students and residents. Given the complexity and time pressure of medical education, these deficiencies will be hard to correct, but this project can serve as a basis for developing a curriculum in study design and statistical methods needed by physicians-in-training.

A CAUSAL RELATIONSHIP BETWEEN OIL PRICES CURRENT ACCOUNT DEFICIT, AND ECONOMIC GROWTH: AN EMPIRICAL ANALYSIS FROM FRAGILE FIVE COUNTRIES

Directory of Open Access Journals (Sweden)

Yuksel BAYRAKTAR

2016-09-01

Full Text Available The main objective of this study is to determine the impact of oil prices in the Fragile-Five countries (Brazil, Indonesia, South Africa, India, and Turkey on current account deficit and growth. In this study, the method of panel data analysis was used and the period of 1980-2014 was examined. The Levin, Lin, & Chu panel; Im, Pesaran, and Shin W-stat; ADF-Fisher Chi-square; and PP-Fisher Chi-square unit root tests were used to determine the stability of data before panel data analysis. The results of the study can be expressed as follows. i There was a statistically meaningful relationship in oil prices with both GDP and the current account deficit. While there was a positive correlation between oil prices and GDP, there was a negative relationship between oil prices and current account deficit. ii No long-term relationship was found between GDP and oil prices; there was a long-term relationship between current account deficit and oil prices as determined by the cointegration tests. iii Causality test also showed the presence of a bidirectional relationship between GDP and oil prices.  Causality between oil prices and the current account deficit was one-way from the variable of oil price to the variable of current account deficit.

A convenient method for X-ray analysis in TEM that measures mass thickness and composition

Science.gov (United States)

Statham, P.; Sagar, J.; Holland, J.; Pinard, P.; Lozano-Perez, S.

2018-01-01

We consider a new approach for quantitative analysis in transmission electron microscopy (TEM) that offers the same convenience as single-standard quantitative analysis in scanning electron microscopy (SEM). Instead of a bulk standard, a thin film with known mass thickness is used as a reference. The procedure involves recording an X-ray spectrum from the reference film for each session of acquisitions on real specimens. There is no need to measure the beam current; the current only needs to be stable for the duration of the session. A new reference standard with a large (1 mm x 1 mm) area of uniform thickness of 100 nm silicon nitride is used to reveal regions of X-ray detector occlusion that would give misleading results for any X-ray method that measures thickness. Unlike previous methods, the new X-ray method does not require an accurate beam current monitor but delivers equivalent accuracy in mass thickness measurement. Quantitative compositional results are also automatically corrected for specimen self-absorption. The new method is tested using a wedge specimen of Inconel 600 that is used to calibrate the high angle angular dark field (HAADF) signal to provide a thickness reference and results are compared with electron energy-loss spectrometry (EELS) measurements. For the new X-ray method, element composition results are consistent with the expected composition for the alloy and the mass thickness measurement is shown to provide an accurate alternative to EELS for thickness determination in TEM without the uncertainty associated with mean free path estimates.

Analysis by absorption and scattering of radiation. A current bibliography

International Nuclear Information System (INIS)

Bujdoso, E.

2002-01-01

A current bibliography with 100 references based on INIS Atomindex has been compiled on Analysis by absorption and scattering of radiation for years 1998-1999. References are arranged by first author's names. (N.T.)

An efficient 3-D eddy-current solver using an independent impedance method for transcranial magnetic stimulation.

Science.gov (United States)

De Geeter, Nele; Crevecoeur, Guillaume; Dupre, Luc

2011-02-01

In many important bioelectromagnetic problem settings, eddy-current simulations are required. Examples are the reduction of eddy-current artifacts in magnetic resonance imaging and techniques, whereby the eddy currents interact with the biological system, like the alteration of the neurophysiology due to transcranial magnetic stimulation (TMS). TMS has become an important tool for the diagnosis and treatment of neurological diseases and psychiatric disorders. A widely applied method for simulating the eddy currents is the impedance method (IM). However, this method has to contend with an ill conditioned problem and consequently a long convergence time. When dealing with optimal design problems and sensitivity control, the convergence rate becomes even more crucial since the eddy-current solver needs to be evaluated in an iterative loop. Therefore, we introduce an independent IM (IIM), which improves the conditionality and speeds up the numerical convergence. This paper shows how IIM is based on IM and what are the advantages. Moreover, the method is applied to the efficient simulation of TMS. The proposed IIM achieves superior convergence properties with high time efficiency, compared to the traditional IM and is therefore a useful tool for accurate and fast TMS simulations.

Potential of the PIGE method in the analysis of biological and mineral materials

International Nuclear Information System (INIS)

Havranek, V.

2006-01-01

A possible application of the PIGE method for the analysis of the biological and mineral samples has been tested using a 3.5 MeV Van de Graaff accelerator. The limits of detection of 4 mg/kg for fluorine, 10 mg/kg for aluminium and 200 mg/kg for phosphorus were achieved with a 3.15 MeV proton beam (8 mm in diameter, 20 nA current and 1000 s irradiation time). The PIGE method was found to be a suitable method for the determination of fluorine in the samples analyzed. With this technique, total fluorine in the sample can be quantitated without any chemical treatment. In the analysis of the phosphorus in thick biological samples, PIGE can compete with PIXE and is probably less sensitive to matrix effects and spectra fitting, which may bring about a higher accuracy of the results

Development of advanced MCR task analysis methods

International Nuclear Information System (INIS)

Na, J. C.; Park, J. H.; Lee, S. K.; Kim, J. K.; Kim, E. S.; Cho, S. B.; Kang, J. S.

2008-07-01

This report describes task analysis methodology for advanced HSI designs. Task analyses was performed by using procedure-based hierarchical task analysis and task decomposition methods. The results from the task analysis were recorded in a database. Using the TA results, we developed static prototype of advanced HSI and human factors engineering verification and validation methods for an evaluation of the prototype. In addition to the procedure-based task analysis methods, workload estimation based on the analysis of task performance time and analyses for the design of information structure and interaction structures will be necessary

A review of flow analysis methods for determination of radionuclides in nuclear wastes and nuclear reactor coolants.

Science.gov (United States)

Trojanowicz, Marek; Kołacińska, Kamila; Grate, Jay W

2018-06-01

The safety and security of nuclear power plant operations depend on the application of the most appropriate techniques and methods of chemical analysis, where modern flow analysis methods prevail. Nevertheless, the current status of the development of these methods is more limited than it might be expected based on their genuine advantages. The main aim of this paper is to review the automated flow analysis procedures developed with various detection methods for the nuclear energy industry. The flow analysis methods for the determination of radionuclides, that have been reported to date, are primarily focused on their environmental applications. The benefits of the application of flow methods in both monitoring of the nuclear wastes and process analysis of the primary circuit coolants of light water nuclear reactors will also be discussed. The application of either continuous flow methods (CFA) or injection methods (FIA, SIA) of the flow analysis with the β-radiometric detection shortens the analysis time and improves the precision of determination due to mechanization of certain time-consuming operations of the sample processing. Compared to the radiometric detection, the mass spectrometry (MS) detection enables one to perform multicomponent analyses as well as the determination of transuranic isotopes with much better limits of detection. Copyright © 2018 Elsevier B.V. All rights reserved.

Current antiviral drugs and their analysis in biological materials - Part II: Antivirals against hepatitis and HIV viruses.

Science.gov (United States)

Nováková, Lucie; Pavlík, Jakub; Chrenková, Lucia; Martinec, Ondřej; Červený, Lukáš

2018-01-05

This review is a Part II of the series aiming to provide comprehensive overview of currently used antiviral drugs and to show modern approaches to their analysis. While in the Part I antivirals against herpes viruses and antivirals against respiratory viruses were addressed, this part concerns antivirals against hepatitis viruses (B and C) and human immunodeficiency virus (HIV). Many novel antivirals against hepatitis C virus (HCV) and HIV have been introduced into the clinical practice over the last decade. The recent broadening portfolio of these groups of antivirals is reflected in increasing number of developed analytical methods required to meet the needs of clinical terrain. Part II summarizes the mechanisms of action of antivirals against hepatitis B virus (HBV), HCV, and HIV, their use in clinical practice, and analytical methods for individual classes. It also provides expert opinion on state of art in the field of bioanalysis of these drugs. Analytical methods reflect novelty of these chemical structures and use by far the most current approaches, such as simple and high-throughput sample preparation and fast separation, often by means of UHPLC-MS/MS. Proper method validation based on requirements of bioanalytical guidelines is an inherent part of the developed methods. Copyright © 2017 Elsevier B.V. All rights reserved.

A review of spurious currents in the lattice Boltzmann method for multiphase flows

Energy Technology Data Exchange (ETDEWEB)

Conning Ton, Kevin; Lee, Tae Hun [The City College of the City Univ. of New York, New York (United States)

2012-12-15

A spurious current is a small amplitude artificial velocity field which arises from an imbalance between discretized forces in multiphase/multi component flows. If it occurs, the velocity field may persist indefinitely, preventing the achievement of a true equilibrium state. Spurious velocities can sometimes be as large as the characteristic velocities of the problem, causing severe instability and ambiguity between physical and spurious velocities. They are typically exacerbated by large values of numerical surface tension or when the two fluids being simulated have large density ratios. The resulting instability can restrict what parameters may be simulated. To varying degrees, spurious currents are found in all multiphase flow models of the lattice Boltzmann method (LBM). There have been many studies of the occurrence of the phenomenon, and many suggestions on how to eliminate it. This paper reviews the three main models of simulating multiphase/multi component flow in the lattice Boltzmann method, as well as the subsequent modifications made in order to reduce or eliminate spurious currents.

New signal processing methods for the evaluation of eddy current NDT data

International Nuclear Information System (INIS)

Anon.

1987-01-01

Signal processing and pattern recognition methods play a crucial role in a number of areas associated with nondestructive evaluation. Defect characterization schemes often involve mapping the signal onto an appropriate feature domain and using pattern recognition techniques for classification. In addition, signal processing methods are also used to acquire, enhance, restore, and compress data. EPRI Project RP 2673-4 is concerned with developing new signal processing and pattern recognition techniques for evaluating eddy current signals. Efforts under this project have focused on three closely related areas. The thrust has been to: (1) develop a scheme to compress eddy current signals for the purposes of storing them in a compact form, (2) develop a robust clustering algorithm capable of discarding feature vectors that fall in the gray areas between clusters, and (3) investigate the feasibility of designing and developing a digital eddyscope

3D spatially-adaptive canonical correlation analysis: Local and global methods.

Science.gov (United States)

Yang, Zhengshi; Zhuang, Xiaowei; Sreenivasan, Karthik; Mishra, Virendra; Curran, Tim; Byrd, Richard; Nandy, Rajesh; Cordes, Dietmar

2018-04-01

Local spatially-adaptive canonical correlation analysis (local CCA) with spatial constraints has been introduced to fMRI multivariate analysis for improved modeling of activation patterns. However, current algorithms require complicated spatial constraints that have only been applied to 2D local neighborhoods because the computational time would be exponentially increased if the same method is applied to 3D spatial neighborhoods. In this study, an efficient and accurate line search sequential quadratic programming (SQP) algorithm has been developed to efficiently solve the 3D local CCA problem with spatial constraints. In addition, a spatially-adaptive kernel CCA (KCCA) method is proposed to increase accuracy of fMRI activation maps. With oriented 3D spatial filters anisotropic shapes can be estimated during the KCCA analysis of fMRI time courses. These filters are orientation-adaptive leading to rotational invariance to better match arbitrary oriented fMRI activation patterns, resulting in improved sensitivity of activation detection while significantly reducing spatial blurring artifacts. The kernel method in its basic form does not require any spatial constraints and analyzes the whole-brain fMRI time series to construct an activation map. Finally, we have developed a penalized kernel CCA model that involves spatial low-pass filter constraints to increase the specificity of the method. The kernel CCA methods are compared with the standard univariate method and with two different local CCA methods that were solved by the SQP algorithm. Results show that SQP is the most efficient algorithm to solve the local constrained CCA problem, and the proposed kernel CCA methods outperformed univariate and local CCA methods in detecting activations for both simulated and real fMRI episodic memory data. Copyright © 2017 Elsevier Inc. All rights reserved.

Analysis of transient state in HTS tapes under ripple DC load current

Science.gov (United States)

Stepien, M.; Grzesik, B.

2014-05-01

The paper concerns the analysis of transient state (quench transition) in HTS tapes loaded with the current having DC component together with a ripple component. Two shapes of the ripple were taken into account: sinusoidal and triangular. Very often HTS tape connected to a power electronic current supply (i.e. superconducting coil for SMES) that delivers DC current with ripples and it needs to be examined under such conditions. Additionally, measurements of electrical (and thermal) parameters under such ripple excitation is useful to tape characterization in broad range of load currents. The results presented in the paper were obtained using test bench which contains programmable DC supply and National Instruments data acquisition system. Voltage drops and load currents were measured vs. time. Analysis of measured parameters as a function of the current was used to tape description with quench dynamics taken into account. Results of measurements were also used to comparison with the results of numerical modelling based on FEM. Presented provisional results show possibility to use results of measurements in transient state to prepare inverse models of superconductors and their detailed numerical modelling.

Superconducting coil manufacturing method for low current dc beam line magnets

International Nuclear Information System (INIS)

Satti, J.A.

1977-01-01

A method of manufacturing superconducting multipole coils for 40 to 50 kG dc beam line magnets with low current is described. Small coils were built and tested successfully to short sample characteristics. The coils did not train after the first cooldown. The coils are porous and well cooled to cope with mechanical instability and energy deposited in the coil from the beam particles. The coils are wound with insulated strand cable. The cable is shaped rectangularly for winding simplicity and good tolerances. After the coil is wound, the insulated strands are electrically connected in series. This reduces the operating current and, most important, improves the coil quench propagation due to heat conduction of one strand adjacent to the other. A well distributed quench allows the magnet energy to distribute more uniformly to the copper in the superconductor wire, giving self-protected coils. A one-meter long, 43 kG, 6-inch bore tube superconducting dipole is now being fabricated. The porous coil design and coil winding methods are discussed

Parametric Methods for Order Tracking Analysis

DEFF Research Database (Denmark)

Nielsen, Jesper Kjær; Jensen, Tobias Lindstrøm

2017-01-01

Order tracking analysis is often used to find the critical speeds at which structural resonances are excited by a rotating machine. Typically, order tracking analysis is performed via non-parametric methods. In this report, however, we demonstrate some of the advantages of using a parametric method...

Comparison between the Gauss' law method and the zero current method to calculate multi-species ionic diffusion in saturated uncharged porous materials

DEFF Research Database (Denmark)

Johannesson, Björn

2010-01-01

There exist, mainly, two different continuum approaches to calculate transient multi species ionic diffusion. One of them is based on explicitly assuming a zero current in the diffusing mixture together with an introduction of a streaming electrical potential in the constitutive equations...... of the coupled set of equation in favor of the staggering approach. A one step truly implicit time stepping scheme is adopted together with an implementation of a modified Newton-Raphson iterational scheme for search of equilibrium at each considered time step calculation. Results from the zero current case...... difference of the two types of potentials, that is, the streaming electrical potential and the electrical field is carefully examined. A novel numerical method based on the finite element approach is established for the zero current method case. The proposed numerical method uses the direct calculation...

Hg stable isotope analysis by the double-spike method.

Science.gov (United States)

Mead, Chris; Johnson, Thomas M

2010-06-01

Recent publications suggest great potential for analysis of Hg stable isotope abundances to elucidate sources and/or chemical processes that control the environmental impact of mercury. We have developed a new MC-ICP-MS method for analysis of mercury isotope ratios using the double-spike approach, in which a solution containing enriched (196)Hg and (204)Hg is mixed with samples and provides a means to correct for instrumental mass bias and most isotopic fractionation that may occur during sample preparation and introduction into the instrument. Large amounts of isotopic fractionation induced by sample preparation and introduction into the instrument (e.g., by batch reactors) are corrected for. This may greatly enhance various Hg pre-concentration methods by correcting for minor fractionation that may occur during preparation and removing the need to demonstrate 100% recovery. Current precision, when ratios are normalized to the daily average, is 0.06 per thousand, 0.06 per thousand, 0.05 per thousand, and 0.05 per thousand (2sigma) for (202)Hg/(198)Hg, (201)Hg/(198)Hg, (200)Hg/(198)Hg, and (199)Hg/(198)Hg, respectively. This is slightly better than previously published methods. Additionally, this precision was attained despite the presence of large amounts of other Hg isotopes (e.g., 5.0% atom percent (198)Hg) in the spike solution; substantially better precision could be achieved if purer (196)Hg were used.

Convergence analysis of the rebalance methods in multiplying finite slab having periodic boundary conditions

International Nuclear Information System (INIS)

Hong, Ser Gi; Lee, Young Ouk; Song, Jae Seung

2009-01-01

This paper analyzes the convergence of the rebalance iteration methods for the discrete ordinates transport equation in the multiplying finite slab problem. The finite slab is assumed to be homogeneous and it has the periodic boundary conditions. A general formulation is used to include three well-known rebalance methods of the linearized form in a unified way. The rebalance iteration methods considered in this paper are the CMR (Coarse-Mesh Rebalance), the CMFD (Coarse-Mesh Finite Difference), and p-CMFD (Partial Current-Based Coarse Mesh Finite Difference) methods which have been popularly used in the reactor physics. The convergence analysis is performed with the well-known Fourier analysis through a linearization. The analyses are applied for one-group problems. The theoretical analysis shows that there are one fundamental mode and N-1 Eigen-modes which determine the convergence if the finite slab is divided into N uniform meshes. The numerical tests show that the Fourier convergence analysis provides the reasonable estimate of the numerical spectral radii for the model problems and the spectral radius for the finite slab approaches the one for the infinite slab as the thickness of the slab increases. (author)

Adaptation of eddy current methods to the multiple problems of reactor testing

International Nuclear Information System (INIS)

Stumm, W.

1975-01-01

In reactor testing, the eddy current method is mainly used for the testing of surface regions inside the pressure vessel, on welds and joints, and for the testing of thin-walled pipes, e.g. the heat exchanger pipes. (RW/AK) [de

Methods of plant root exudates analysis: a review

Directory of Open Access Journals (Sweden)

Peter Dundek

2011-01-01

Full Text Available The aim of this review is to summarise current knowledge on methods being used to determine individual compounds and properties of water-soluble plant root exudates. These compounds include amino acids, organic acids and simple sugars, as well as polysaccharides, proteins and organic substances. Qualitative composition of water-soluble root exudates and exudation rate are commonly measured with the aim of consequent synthetic preparation of plant root exudates to be supplied to soil to create artificial rhizosphere for different experimental purposes. Root exudates collection usually requires consequent filtration or centrifugation to remove solids, root detritus and microbial cell debris, and consequent concentration using an evaporator, lyophilizator or ultrafiltration. Methods used for analysis of total groups of compounds (total proteins and total carbohydrates and total organic carbon are simple. On the other hand, HPLC or GS/MS are commonly used to analyse individual low molecular weight organic molecules (sugars, organic acids and amino acids with separation using different columns. Other properties such as pH, conductivity or activity of different enzymes as well as gel electrophoresis of proteins are sometimes assessed. All of these methods are discussed in this work.

A Start-up Calibration Method for Generic Current-Steering D/A Converters with Optimal Area Solution

NARCIS (Netherlands)

Radulov, G.I.; Quinn, P.J.; Hegt, J.A.; Roermund, van A.H.M.

2005-01-01

This paper presents a new start-up calibration method for current-steering D/A converters, based on a 1-bit ADC. The paper proposes a new current cell that allows calibration of non-identical current sources by way of a shared calibration apparatus. The current cell uses parallel selfcalibrated unit

Comparison between laser terahertz emission microscope and conventional methods for analysis of polycrystalline silicon solar cell

Directory of Open Access Journals (Sweden)

Hidetoshi Nakanishi

2015-11-01

Full Text Available A laser terahertz emission microscope (LTEM can be used for noncontact inspection to detect the waveforms of photoinduced terahertz emissions from material devices. In this study, we experimentally compared the performance of LTEM with conventional analysis methods, e.g., electroluminescence (EL, photoluminescence (PL, and laser beam induced current (LBIC, as an inspection method for solar cells. The results showed that LTEM was more sensitive to the characteristics of the depletion layer of the polycrystalline solar cell compared with EL, PL, and LBIC and that it could be used as a complementary tool to the conventional analysis methods for a solar cell.

Comparative Analysis Of Conventional Method With Activity Based Costing In PT Mulia Sejati Gallery

Directory of Open Access Journals (Sweden)

Irma Nadia Erena

2016-09-01

Full Text Available The goal of this research was to provide readers the information about the calculation methods, both traditional and activity-based costing in the application of the cost of production. The method used in this research was the qualitative method. The analysis was done by calculating the amount of the production cost using the traditional system and the magnitude of the production cost when using the activity-based costing system. The amount of each acquisition was then performed into data analysis. The results achieved are massive distortion between the calculations using traditional systems and activity based costing system. The conclusions of the whole thesis are activity-based costing system is considered more relevant than traditional systems that are currently used by the company.

Analysis of the wake field effects in the PEP-II storage rings with extremely high currents

Energy Technology Data Exchange (ETDEWEB)

Novokhatski, A., E-mail: novo@slac.stanford.edu; Seeman, J.; Sullivan, M.

2014-01-21

We present the history and analysis of different wake field effects throughout the operational life of the PEP-II SLAC B-factory. Although the impedance of the high and low energy rings is small, the intense high-current beams generated a lot of power. The effects from these wake fields are: heating and damage of vacuum beam chamber elements like RF seals, vacuum valves, shielded bellows, BPM buttons and ceramic tiles; vacuum spikes, vacuum instabilities and high detector background; and beam longitudinal and transverse instabilities. We also discuss the methods used to eliminate these effects. Results of this analysis and the PEP-II experience may be very useful in the design of new storage rings and light sources.

Hypothesis analysis methods, hypothesis analysis devices, and articles of manufacture

Science.gov (United States)

Sanfilippo, Antonio P [Richland, WA; Cowell, Andrew J [Kennewick, WA; Gregory, Michelle L [Richland, WA; Baddeley, Robert L [Richland, WA; Paulson, Patrick R [Pasco, WA; Tratz, Stephen C [Richland, WA; Hohimer, Ryan E [West Richland, WA

2012-03-20

Hypothesis analysis methods, hypothesis analysis devices, and articles of manufacture are described according to some aspects. In one aspect, a hypothesis analysis method includes providing a hypothesis, providing an indicator which at least one of supports and refutes the hypothesis, using the indicator, associating evidence with the hypothesis, weighting the association of the evidence with the hypothesis, and using the weighting, providing information regarding the accuracy of the hypothesis.

Investigation on method of elasto-plastic analysis for piping system (benchmark analysis)

International Nuclear Information System (INIS)

Kabaya, Takuro; Kojima, Nobuyuki; Arai, Masashi

2015-01-01

This paper provides method of an elasto-plastic analysis for practical seismic design of nuclear piping system. JSME started up the task to establish method of an elasto-plastic analysis for nuclear piping system. The benchmark analyses have been performed in the task to investigate on method of an elasto-plastic analysis. And our company has participated in the benchmark analyses. As a result, we have settled on the method which simulates the result of piping exciting test accurately. Therefore the recommended method of an elasto-plastic analysis is shown as follows; 1) An elasto-plastic analysis is composed of dynamic analysis of piping system modeled by using beam elements and static analysis of deformed elbow modeled by using shell elements. 2) Bi-linear is applied as an elasto-plastic property. Yield point is standardized yield point multiplied by 1.2 times, and second gradient is 1/100 young's modulus. Kinematic hardening is used as a hardening rule. 3) The fatigue life is evaluated on strain ranges obtained by elasto-plastic analysis, by using the rain flow method and the fatigue curve of previous studies. (author)

Comparative evaluation of three cognitive error analysis methods through an application to accident management tasks in NPPs

International Nuclear Information System (INIS)

Jung, Won Dea; Kim, Jae Whan; Ha, Jae Joo; Yoon, Wan C.

1999-01-01

This study was performed to comparatively evaluate selected Human Reliability Analysis (HRA) methods which mainly focus on cognitive error analysis, and to derive the requirement of a new human error analysis (HEA) framework for Accident Management (AM) in nuclear power plants(NPPs). In order to achieve this goal, we carried out a case study of human error analysis on an AM task in NPPs. In the study we evaluated three cognitive HEA methods, HRMS, CREAM and PHECA, which were selected through the review of the currently available seven cognitive HEA methods. The task of reactor cavity flooding was chosen for the application study as one of typical tasks of AM in NPPs. From the study, we derived seven requirement items for a new HEA method of AM in NPPs. We could also evaluate the applicability of three cognitive HEA methods to AM tasks. CREAM is considered to be more appropriate than others for the analysis of AM tasks. But, PHECA is regarded less appropriate for the predictive HEA technique as well as for the analysis of AM tasks. In addition to these, the advantages and disadvantages of each method are described. (author)

[Development and current situation of reconstruction methods following total sacrectomy].

Science.gov (United States)

Huang, Siyi; Ji, Tao; Guo, Wei

2018-05-01

To review the development of the reconstruction methods following total sacrectomy, and to provide reference for finding a better reconstruction method following total sacrectomy. The case reports and biomechanical and finite element studies of reconstruction following total sacrectomy at home and abroad were searched. Development and current situation were summarized. After developing for nearly 30 years, great progress has been made in the reconstruction concept and fixation techniques. The fixation methods can be summarized as the following three strategies: spinopelvic fixation (SPF), posterior pelvic ring fixation (PPRF), and anterior spinal column fixation (ASCF). SPF has undergone technical progress from intrapelvic rod and hook constructs to pedicle and iliac screw-rod systems. PPRF and ASCF could improve the stability of the reconstruction system. Reconstruction following total sacrectomy remains a challenge. Reconstruction combining SPF, PPRF, and ASCF is the developmental direction to achieve mechanical stability. How to gain biological fixation to improve the long-term stability is an urgent problem to be solved.

A comparison of two psychological screening methods currently used for inpatients in a UK burns service.

Science.gov (United States)

Shepherd, Laura; Tew, Victoria; Rai, Lovedeep

2017-12-01

Various types of psychological screening are currently used in the UK to identify burn patients who are experiencing psychological distress and may need additional support and intervention during their hospital admission. This audit compared two types of psychological screening in 40 burn inpatients. One screening method was an unpublished questionnaire designed to explore multiple areas of potential distress for those who have experienced burns. The other method was an indirect psychological screen via discussions within multi-disciplinary team (MDT) meetings where a Clinical Psychologist was present to guide and prompt psychological discussions. Data was collected between November 2012 and September 2016. Results suggested that both screening methods were similar in identifying patients who benefit from more formal psychological assessment. Indeed, statistical analysis reported no difference between the two screening methods (N=40, p=.424, two-tailed). In conclusion, measuring distress in burns inpatients using a burns-specific questionnaire and psychological discussions within MDT meetings are similar in their ability to identify patients in need of more thorough psychological assessment. However, both screening methods identified patients who were in need of psychological input when the other did not. This suggests that psychological screening of burns inpatients, and the psychological difficulties that they can present with, is complex. The advantages and disadvantages of both methods of screening are discussed. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

From thermometric to spectrophotometric kinetic-catalytic methods of analysis. A review.

Science.gov (United States)

Cerdà, Víctor; González, Alba; Danchana, Kaewta

2017-05-15

Kinetic-catalytic analytical methods have proved to be very easy and highly sensitive strategies for chemical analysis, that rely on simple instrumentation [1,2]. Molecular absorption spectrophotometry is commonly used as the detection technique. However, other detection systems, like electrochemical or thermometric ones, offer some interesting possibilities since they are not affected by the color or turbidity of the samples. In this review some initial experience with thermometric kinetic-catalytic methods is described, up to our current experience exploiting spectrophotometric flow techniques to automate this kind of reactions, including the use of integrated chips. Procedures for determination of inorganic and organic species in organic and inorganic matrices are presented. Copyright © 2017 Elsevier B.V. All rights reserved.

Scope-Based Method Cache Analysis

DEFF Research Database (Denmark)

Huber, Benedikt; Hepp, Stefan; Schoeberl, Martin

2014-01-01

The quest for time-predictable systems has led to the exploration of new hardware architectures that simplify analysis and reasoning in the temporal domain, while still providing competitive performance. For the instruction memory, the method cache is a conceptually attractive solution, as it req......The quest for time-predictable systems has led to the exploration of new hardware architectures that simplify analysis and reasoning in the temporal domain, while still providing competitive performance. For the instruction memory, the method cache is a conceptually attractive solution...

Methods for RNA Analysis

DEFF Research Database (Denmark)

Olivarius, Signe

of the transcriptome, 5’ end capture of RNA is combined with next-generation sequencing for high-throughput quantitative assessment of transcription start sites by two different methods. The methods presented here allow for functional investigation of coding as well as noncoding RNA and contribute to future...... RNAs rely on interactions with proteins, the establishment of protein-binding profiles is essential for the characterization of RNAs. Aiming to facilitate RNA analysis, this thesis introduces proteomics- as well as transcriptomics-based methods for the functional characterization of RNA. First, RNA...

Effect-directed analysis: Current status and future challenges

Science.gov (United States)

Hong, Seongjin; Giesy, John P.; Lee, Jung-Suk; Lee, Jong-Hyeon; Khim, Jong Seong

2016-09-01

Effect-directed analysis (EDA) has become useful for identification of toxicant(s) that occur in mixtures in the environment, especially those that are causative agents of specific adverse effects. Here, we summarize and review EDA methodology including preparation of samples, biological analyses, fractionations, and instrumental analyses, highlighting key scientific advancements. A total of 63 documents since 1999 (Scopus search) including 46 research articles, 13 review papers, and 4 project descriptions, have been collected and reviewed in this study. At the early stage (1999-2010), most studies that applied EDA focused on organic extracts of freshwater and coastal contaminated sediments and wastewater. Toxic effects were often measured using cell-based bioassays ( in vitro) and the causative chemicals were identified by use of low resolution gas chromatography with mass selective detector (GCMSD). More recently (2010-present), EDA has been extended to various matrices such as biota, soil, crude oil, and suspended solids and techniques have been improved to include determination of bioavailability in vivo. In particular, methods for non-target screenings of organic chemicals in environmental samples using cutting-edge instrumentation such as time of flight-mass spectrometry (ToF-MS), Fourier transform-ion cyclotron resonance (FT-ICR), and Orbitrap mass spectrometer have been developed. This overview provides descriptions of recent improvements of EDA and suggests future research directions based on current understandings and limitations.

Garter spring location of pressure tube for PHWR using eddy current testing methods

International Nuclear Information System (INIS)

Lee, Y. S.; Yang, D. J.; Jeong, H. K.

2001-01-01

There are garter springs between pressure tube and calandria tube for PHWR. If the space of these garter springs become to be changed, the sagging of tube is caused and the contact between the pressure tube and calandria tube will cause the tube to be failed. AECL has applied the eddy current testing methods using send-receive type probe for this purpose, but this study apply eddy current testing methods using bobbin differential type probe to detection of garter spring location. And we did the computer simulation using VIC-3D code and compared it with experiments results for inspection 1 ∼ 11kHz. The results was that the garter spring signal was successfully detected for every frequency, and 5 kHz was best

Multi-terminal direct-current grids modeling, analysis, and control

CERN Document Server

Chaudhuri, Nilanjan; Majumder, Rajat; Yazdani, Amirnaser

2014-01-01

A comprehensive modeling, analysis, and control design framework for multi-terminal direct current (MTDC) grids is presented together with their interaction with the surrounding AC networks and the impact on overall stability. The first book of its kind on the topic of multi-terminal DC (MTDC) grids  Presents a comprehensive modeling framework for MTDC grids which is compatible with the standard AC system modeling for stability studies Includes modal analysis and study of the interactions between the MTDC grid and the surrounding AC systems Addresses the problems of autonomous power sharing an

Comparison of Flood Frequency Analysis Methods for Ungauged Catchments in France

Directory of Open Access Journals (Sweden)

Jean Odry

2017-09-01

Full Text Available The objective of flood frequency analysis (FFA is to associate flood intensity with a probability of exceedance. Many methods are currently employed for this, ranging from statistical distribution fitting to simulation approaches. In many cases the site of interest is actually ungauged, and a regionalisation scheme has to be associated with the FFA method, leading to a multiplication of the number of possible methods available. This paper presents the results of a wide-range comparison of FFA methods from statistical and simulation families associated with different regionalisation schemes based on regression, or spatial or physical proximity. The methods are applied to a set of 1535 French catchments, and a k-fold cross-validation procedure is used to consider the ungauged configuration. The results suggest that FFA from the statistical family largely relies on the regionalisation step, whereas the simulation-based method is more stable regarding regionalisation. This conclusion emphasises the difficulty of the regionalisation process. The results are also contrasted depending on the type of climate: the Mediterranean catchments tend to aggravate the differences between the methods.

A Linear Birefringence Measurement Method for an Optical Fiber Current Sensor.

Science.gov (United States)

Xu, Shaoyi; Shao, Haiming; Li, Chuansheng; Xing, Fangfang; Wang, Yuqiao; Li, Wei

2017-07-03

In this work, a linear birefringence measurement method is proposed for an optical fiber current sensor (OFCS). First, the optical configuration of the measurement system is presented. Then, the elimination method of the effect of the azimuth angles between the sensing fiber and the two polarizers is demonstrated. Moreover, the relationship of the linear birefringence, the Faraday rotation angle and the final output is determined. On these bases, the multi-valued problem on the linear birefringence is simulated and its solution is illustrated when the linear birefringence is unknown. Finally, the experiments are conducted to prove the feasibility of the proposed method. When the numbers of turns of the sensing fiber in the OFCS are about 15, 19, 23, 27, 31, 35, and 39, the measured linear birefringence obtained by the proposed method are about 1.3577, 1.8425, 2.0983, 2.5914, 2.7891, 3.2003 and 3.5198 rad. Two typical methods provide the references for the proposed method. The proposed method is proven to be suitable for the linear birefringence measurement in the full range without the limitation that the linear birefringence must be smaller than π/2.

78 FR 48636 - Current Good Manufacturing Practice and Hazard Analysis and Risk-Based Preventive Controls for...

Science.gov (United States)

2013-08-09

... collection related to the proposed rule, ``Current Good Manufacturing Practice and Hazard Analysis and Risk... period. These two proposals are related to the proposed rule ``Current Good Manufacturing Practice and... final extension of the comment period for the ``Current Good Manufacturing Practice and Hazard Analysis...

Computational methods in power system analysis

CERN Document Server

Idema, Reijer

2014-01-01

This book treats state-of-the-art computational methods for power flow studies and contingency analysis. In the first part the authors present the relevant computational methods and mathematical concepts. In the second part, power flow and contingency analysis are treated. Furthermore, traditional methods to solve such problems are compared to modern solvers, developed using the knowledge of the first part of the book. Finally, these solvers are analyzed both theoretically and experimentally, clearly showing the benefits of the modern approach.

Family planning knowledge and current use of contraception among the Mru indigenous women in Bangladesh: a multivariate analysis

Directory of Open Access Journals (Sweden)

Islam MR

2012-02-01

Full Text Available M Rakibul Islam1, Gunnar Thorvaldsen21Bangladesh Agricultural University, Bangladesh; 2Norwegian Historical Data Centre, University of Tromsø, NorwayBackground: This article aims to understand the family planning (FP knowledge and current use of contraception and its predictors among women of the Mru people – the most underprivileged indigenous community in Bangladesh.Methods: In this study, 374 currently married Mru women were interviewed and selected purposively from three upazilas (administrative subdistricts of the Bandarban area, where most of the Mru people live. The association between the variables was assessed in bivariate analysis using the Chi-square test and binary logistic regression models were employed to explore the predictors of FP knowledge and current use of contraception among the Mru women.Results: Only about 40% of respondents had ever heard FP messages or about FP methods – two-fifths of the national figure (99.9%. The current use of contraception was much lower (25.1% among the Mru people than at the national level (55.8%. Among both modern and traditional methods, the contraceptive pill ranked first. About two-thirds (66.0% of married women used this method – more than two times than the national figure (28.5%. On the other hand, the prevalence of male methods was comparatively lower than at the national level. Logistic regression models revealed that place of residence, religion, age, school attendance, husband's school attendance, service provided in the community, distance to the service center, and exposure to mass media had significant effects on knowledge of FP and on use of contraception.Conclusion: Education for mothers and vernacular language-based doorstep FP programs with special emphasis on awareness are suggested for the community.Keywords: family planning, contraceptive use, the Mru, logistic regression, Bangladesh

Standard test method for isotopic analysis of uranium hexafluoride by double standard single-collector gas mass spectrometer method

CERN Document Server

American Society for Testing and Materials. Philadelphia

2010-01-01

1.1 This is a quantitative test method applicable to determining the mass percent of uranium isotopes in uranium hexafluoride (UF6) samples with 235U concentrations between 0.1 and 5.0 mass %. 1.2 This test method may be applicable for the entire range of 235U concentrations for which adequate standards are available. 1.3 This test method is for analysis by a gas magnetic sector mass spectrometer with a single collector using interpolation to determine the isotopic concentration of an unknown sample between two characterized UF6 standards. 1.4 This test method is to replace the existing test method currently published in Test Methods C761 and is used in the nuclear fuel cycle for UF6 isotopic analyses. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro...

COMETS2: An advanced MATLAB toolbox for the numerical analysis of electric fields generated by transcranial direct current stimulation.

Science.gov (United States)

Lee, Chany; Jung, Young-Jin; Lee, Sang Jun; Im, Chang-Hwan

2017-02-01

Since there is no way to measure electric current generated by transcranial direct current stimulation (tDCS) inside the human head through in vivo experiments, numerical analysis based on the finite element method has been widely used to estimate the electric field inside the head. In 2013, we released a MATLAB toolbox named COMETS, which has been used by a number of groups and has helped researchers to gain insight into the electric field distribution during stimulation. The aim of this study was to develop an advanced MATLAB toolbox, named COMETS2, for the numerical analysis of the electric field generated by tDCS. COMETS2 can generate any sizes of rectangular pad electrodes on any positions on the scalp surface. To reduce the large computational burden when repeatedly testing multiple electrode locations and sizes, a new technique to decompose the global stiffness matrix was proposed. As examples of potential applications, we observed the effects of sizes and displacements of electrodes on the results of electric field analysis. The proposed mesh decomposition method significantly enhanced the overall computational efficiency. We implemented an automatic electrode modeler for the first time, and proposed a new technique to enhance the computational efficiency. In this paper, an efficient toolbox for tDCS analysis is introduced (freely available at http://www.cometstool.com). It is expected that COMETS2 will be a useful toolbox for researchers who want to benefit from the numerical analysis of electric fields generated by tDCS. Copyright © 2016. Published by Elsevier B.V.

First current density measurements in the ring current region using simultaneous multi-spacecraft CLUSTER-FGM data

Directory of Open Access Journals (Sweden)

C. Vallat

2005-07-01

Full Text Available The inner magnetosphere's current mapping is one of the key elements for current loop closure inside the entire magnetosphere. A method for directly computing the current is the multi-spacecraft curlometer technique, which is based on the application of Maxwell-Ampère's law. This requires the use of four-point magnetic field high resolution measurements. The FGM experiment on board the four Cluster spacecraft allows, for the first time, an instantaneous calculation of the magnetic field gradients and thus a measurement of the local current density. This technique requires, however, a careful study concerning all the factors that can affect the accuracy of the J estimate, such as the tetrahedral geometry of the four spacecraft, or the size and orientation of the current structure sampled. The first part of this paper is thus providing a detailed analysis of the method accuracy, and points out the limitations of this technique in the region of interest. The second part is an analysis of the ring current region, which reveals, for the first time, the large latitudinal extent of the ring current, for all magnetic activity levels, as well as the latitudinal evolution of the perpendicular (and parallel components of the current along the diffuse auroral zone. Our analysis also points out the sharp transition between two distinct plasma regions, with the existence of high diamagnetic currents at the interface, as well as the filamentation of the current inside the inner plasma sheet. A statistical study over multiple perigee passes of Cluster (at about 4 R_E from the Earth reveals the azimuthal extent of the partial ring current. It also reveals that, at these distances and all along the evening sector, there isn't necessarily a strong dependence of the local current density value on the magnetic activity level. This is a direct consequence of the ring current morphology evolution, as well as the relative

Real options analysis for land use management: Methods, application, and implications for policy.

Science.gov (United States)

Regan, Courtney M; Bryan, Brett A; Connor, Jeffery D; Meyer, Wayne S; Ostendorf, Bertram; Zhu, Zili; Bao, Chenming

2015-09-15

Discounted cash flow analysis, including net present value is an established way to value land use and management investments which accounts for the time-value of money. However, it provides a static view and assumes passive commitment to an investment strategy when real world land use and management investment decisions are characterised by uncertainty, irreversibility, change, and adaptation. Real options analysis has been proposed as a better valuation method under uncertainty and where the opportunity exists to delay investment decisions, pending more information. We briefly review the use of discounted cash flow methods in land use and management and discuss their benefits and limitations. We then provide an overview of real options analysis, describe the main analytical methods, and summarize its application to land use investment decisions. Real options analysis is largely underutilized in evaluating land use decisions, despite uncertainty in policy and economic drivers, the irreversibility and sunk costs involved. New simulation methods offer the potential for overcoming current technical challenges to implementation as demonstrated with a real options simulation model used to evaluate an agricultural land use decision in South Australia. We conclude that considering option values in future policy design will provide a more realistic assessment of landholder investment decision making and provide insights for improved policy performance. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Method for Identification of the Equivalent Inductance and Resistance in the Plant Model of Current-Controlled Grid-Tied Converters

DEFF Research Database (Denmark)

Vidal, Ana; Yepes, Alejandro G.; Fernandez, Francisco Daniel Freijedo

2015-01-01

Precise knowledge of the plant time constant L=R is essential to perform a thorough analysis and design of the current control loop in voltage source converters (VSCs). From the perspective of the current controller dynamics in the low frequency range, such plant time constant is also suitable...... for most cases in which an LCL filter is used. As the loop behavior can be significantly influenced by the VSC working conditions, the effects associated to converter losses should be included in the model, through an equivalent series resistance. In addition, the plant inductance may also present...... important uncertainties with respect to the value of the VSC L/LCL interface filter measured at rated conditions. Thus, in this work, a method is presented to estimate both parameters of the plant time constant, i.e., the equivalent inductance and resistance in the plant model of current-controlled VSCs...

comparison of elastic-plastic FE method and engineering method for RPV fracture mechanics analysis

International Nuclear Information System (INIS)

Sun Yingxue; Zheng Bin; Zhang Fenggang

2009-01-01

This paper described the FE analysis of elastic-plastic fracture mechanics for a crack in RPV belt line using ABAQUS code. It calculated and evaluated the stress intensity factor and J integral of crack under PTS transients. The result is also compared with that by engineering analysis method. It shows that the results using engineering analysis method is a little larger than the results using FE analysis of 3D elastic-plastic fracture mechanics, thus the engineering analysis method is conservative than the elastic-plastic fracture mechanics method. (authors)

Capital Finance Decisions for project managers - A reflection on current methods

Directory of Open Access Journals (Sweden)

C. Scheepers

2003-12-01

Full Text Available This paper evaluates some of current financial investment selection methodologies for capital projects. The proc ess (and criteria of capital investment decisions is reviewed. The capital budget for most organisations is prepared annually by a committee of senior managers who then present it for approval by the board of directors. Investment proposals are usually subjected to two financial tests, "payback" and "internal rate of return (IRR". The management committee usually decides on the tests and acceptance criteria vary according to the type of project. Some shortcomings of these most frequently used current tests (Payback & IRR are identified and it is recommended that the Net Present Value (NPV should be used as the primary method for analysing, comparing and selecting capital projects.

Method of measuring the current density distribution and emittance of pulsed electron beams

International Nuclear Information System (INIS)

Schilling, H.B.

1979-07-01

This method of current density measurement employs an array of many Faraday cups, each cup being terminated by an integrating capacitor. The voltages of the capacitors are subsequently displayed on a scope, thus giving the complete current density distribution with one shot. In the case of emittance measurements, a moveable small-diameter aperture is inserted at some distance in front of the cup array. Typical results with a two-cathode, two-energy electron source are presented. (orig.)

Method of recovering oil from alum shales. [heating by electric currents

Energy Technology Data Exchange (ETDEWEB)

Wennerstrom, K G

1918-06-04

A method of treating alum shale and other bituminous shales in order to extract oil et cetera, is characterized by bringing the shale to a temperature at which it melts, and at which the necessary amount of heat is transferred to the molten shale to be distilled. The patent claim is characterized by heating the shale by means of electric current. The patent has one additional claim.

78 FR 64425 - Current Good Manufacturing Practice and Hazard Analysis and Risk-Based Preventive Controls for...

Science.gov (United States)

2013-10-29

..., 507, and 579 [Docket No. FDA-2011-N-0922] Current Good Manufacturing Practice and Hazard Analysis and... requirements for current good manufacturing practice and hazard analysis and risk-based preventive controls for..., packing, or holding of animal food in two ways. First, it would create new current good manufacturing...

The complementary use of radioanalytical methods and trace analysis methods for the characterisation of environmental IAEA reference materials

International Nuclear Information System (INIS)

De Regge, P.; Burns, K.; Campbell, M.; Makarewicz, M.; Markowicz, A.; Mattiuzzi, M.; Tajani, A.; Toervenyi, A.; Zeiller, E.

2001-01-01

The IAEA laboratories have access to both nuclear analytical methods and conventional instrumental methods for trace analysis for the characterisation of its environmental and biological reference materials. A technical concept integrating the homogeneity data, the recommended test portion mass and the uncertainty on the trace element concentrations is explored using a combination of INAA, XRF, ICP-MS, ICP-AES, and AAS. The above approach is illustrated by selected examples of reference materials currently under evaluation for their trace element content. They include some or all of the following elements Al, As, Br, Ca, Cd, Co, Cr, Cs, Cu, Fe, Hg, K, Mg, Mn, Mo, Na, Ni, Pb, Rb, Se, Sr, Th, U, Zn in environmental biomonitor organisms (lichen, algae) and air dust filters. (author)

Methods for seismic analysis of nuclear power plants

International Nuclear Information System (INIS)

Gantenbein, F.

1990-01-01

The seismic analysis of a complex structure, such as a nuclear power plant, is done in various steps. An overview of the methods, used in each of these steps will be given in the following chapters: Seismic analysis of the buildings taking into account structures with important mass or stiffness. The input to the building analysis, called ground motion, is described by an accelerogram or a response spectra. In this step, soil structure interaction has to be taken into account. Various methods are available: Impedance, finite element. The response of the structure can be calculated by spectral method or by time history analysis; advantages and limitations of each method will be shown. Calculation of floor response spectrum which are the data for the equipment analysis. Methods to calculate this spectrum will be described. Seismic analysis of the equipments. Presentation of the methods for both monosupported and multisupported equipment will be given. In addition methods to analyse equipments which present non-linearities associated to the boundary conditions such as impacts, sliding will be presented. (author). 30 refs, 15 figs

A novel frequency analysis method for assessing K(ir)2.1 and Na (v)1.5 currents.

Science.gov (United States)

Rigby, J R; Poelzing, S

2012-04-01

Voltage clamping is an important tool for measuring individual currents from an electrically active cell. However, it is difficult to isolate individual currents without pharmacological or voltage inhibition. Herein, we present a technique that involves inserting a noise function into a standard voltage step protocol, which allows one to characterize the unique frequency response of an ion channel at different step potentials. Specifically, we compute the fast Fourier transform for a family of current traces at different step potentials for the inward rectifying potassium channel, K(ir)2.1, and the channel encoding the cardiac fast sodium current, Na(v)1.5. Each individual frequency magnitude, as a function of voltage step, is correlated to the peak current produced by each channel. The correlation coefficient vs. frequency relationship reveals that these two channels are associated with some unique frequencies with high absolute correlation. The individual IV relationship can then be recreated using only the unique frequencies with magnitudes of high absolute correlation. Thus, this study demonstrates that ion channels may exhibit unique frequency responses.

Matrix pencil method-based reference current generation for shunt active power filters

DEFF Research Database (Denmark)

Terriche, Yacine; Golestan, Saeed; Guerrero, Josep M.

2018-01-01

response and works well under distorted and unbalanced voltage. Moreover, the proposed method can estimate the voltage phase accurately; this property enables the algorithm to compensate for both power factor and current unbalance. The effectiveness of the proposed method is verified using simulation...... are using the discrete Fourier transform (DFT) in the frequency domain or the instantaneous p–q theory and the synchronous reference frame in the time domain. The DFT, however, suffers from the picket-fence effect and spectral leakage. On the other hand, the DFT takes at least one cycle of the nominal...... frequency. The time-domain methods show a weakness under voltage distortion, which requires prior filtering techniques. The aim of this study is to present a fast yet effective method for generating the RCC for SAPFs. The proposed method, which is based on the matrix pencil method, has a fast dynamic...

Speed Control Analysis of Brushless DC Motor Based on Maximum Amplitude DC Current Feedback

Directory of Open Access Journals (Sweden)

Hassan M.A.A.

2014-07-01

Full Text Available This paper describes an approach to develop accurate and simple current controlled modulation technique for brushless DC (BLDC motor drive. The approach is applied to control phase current based on generation of quasi-square wave current by using only one current controller for the three phases. Unlike the vector control method which is complicated to be implemented, this simple current modulation technique presents advantages such as phase currents are kept in balance and the current is controlled through only one dc signal which represent maximum amplitude value of trapezoidal current (Imax. This technique is performed with Proportional Integral (PI control algorithm and triangular carrier comparison method to generate Pulse Width Modulation (PWM signal. In addition, the PI speed controller is incorporated with the current controller to perform desirable speed operation of non-overshoot response. The performance and functionality of the BLDC motor driver are verified via simulation by using MATLAB/SIMULINK. The simulation results show the developed control system performs desirable speed operation of non-overshoot and good current waveforms.

Detection of a static eccentricity fault in a closed loop driven induction motor by using the angular domain order tracking analysis method

Science.gov (United States)

Akar, Mehmet

2013-01-01

In this study, a new method was presented for the detection of a static eccentricity fault in a closed loop operating induction motor driven by inverter. Contrary to the motors supplied by the line, if the speed and load, and therefore the amplitude and frequency, of the current constantly change then this also causes a continuous change in the location of fault harmonics in the frequency spectrum. Angular Domain Order Tracking analysis (AD-OT) is one of the most frequently used fault diagnosis methods in the monitoring of rotating machines and the analysis of dynamic vibration signals. In the presented experimental study, motor phase current and rotor speed were monitored at various speeds and load levels with a healthy and static eccentricity fault in the closed loop driven induction motor with vector control. The AD-OT method was applied to the motor current and the results were compared with the traditional FFT and Fourier Transform based Order Tracking (FT-OT) methods. The experimental results demonstrate that AD-OT method is more efficient than the FFT and FT-OT methods for fault diagnosis, especially while the motor is operating run-up and run-down. Also the AD-OT does not incur any additional cost for the user because in inverter driven systems, current and speed sensor coexist in the system. The main innovative parts of this study are that AD-OT method was implemented on the motor current signal for the first time.

Hamiltonian analysis of fast wave current drive in tokamak plasmas

Energy Technology Data Exchange (ETDEWEB)

Becoulet, A; Fraboulet, D; Giruzzi, G; Moreau, D; Saoutic, B [Association Euratom-CEA, Centre d` Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Chinardet, J [CISI Ingenierie, Centre d` Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France)

1993-12-01

The Hamiltonian formalism is used to analyze the direct resonant interaction between the fast magnetosonic wave and the electrons in a tokamak plasma. The intrinsic stochasticity of the electron phase space trajectories is derived, and together with extrinsic de-correlation processes, assesses the validity of the quasilinear approximation for the kinetic studies of fast wave current drive (FWCD). A full-wave resolution of the Maxwell-Vlasov set of equations provides the exact pattern of the wave fields in a complete tokamak geometry, for a realistic antenna spectrum. The local quasilinear diffusion tensor is derived from the wave fields, and is used for a computation of the driven current and deposited power profiles, the current drive efficiency, including possible non-linear effects in the kinetic equation. Several applications of FWCD on existing and future machines are given, as well as results concerning combination of FWCD with other non inductive current drive methods. An analytical expression for the current drive efficiency is given in the high single-pass absorption regimes. (authors). 20 figs., 1 tab., 26 refs.

Hamiltonian analysis of fast wave current drive in tokamak plasmas

International Nuclear Information System (INIS)

Becoulet, A.; Fraboulet, D.; Giruzzi, G.; Moreau, D.; Saoutic, B.

1993-12-01

The Hamiltonian formalism is used to analyze the direct resonant interaction between the fast magnetosonic wave and the electrons in a tokamak plasma. The intrinsic stochasticity of the electron phase space trajectories is derived, and together with extrinsic de-correlation processes, assesses the validity of the quasilinear approximation for the kinetic studies of fast wave current drive (FWCD). A full-wave resolution of the Maxwell-Vlasov set of equations provides the exact pattern of the wave fields in a complete tokamak geometry, for a realistic antenna spectrum. The local quasilinear diffusion tensor is derived from the wave fields, and is used for a computation of the driven current and deposited power profiles, the current drive efficiency, including possible non-linear effects in the kinetic equation. Several applications of FWCD on existing and future machines are given, as well as results concerning combination of FWCD with other non inductive current drive methods. An analytical expression for the current drive efficiency is given in the high single-pass absorption regimes. (authors). 20 figs., 1 tab., 26 refs

Dimensionality Reduction Methods: Comparative Analysis of methods PCA, PPCA and KPCA

Directory of Open Access Journals (Sweden)

Jorge Arroyo-Hernández

2016-01-01

Full Text Available The dimensionality reduction methods are algorithms mapping the set of data in subspaces derived from the original space, of fewer dimensions, that allow a description of the data at a lower cost. Due to their importance, they are widely used in processes associated with learning machine. This article presents a comparative analysis of PCA, PPCA and KPCA dimensionality reduction methods. A reconstruction experiment of worm-shape data was performed through structures of landmarks located in the body contour, with methods having different number of main components. The results showed that all methods can be seen as alternative processes. Nevertheless, thanks to the potential for analysis in the features space and the method for calculation of its preimage presented, KPCA offers a better method for recognition process and pattern extraction

An imbalance fault detection method based on data normalization and EMD for marine current turbines.

Science.gov (United States)

Zhang, Milu; Wang, Tianzhen; Tang, Tianhao; Benbouzid, Mohamed; Diallo, Demba

2017-05-01

This paper proposes an imbalance fault detection method based on data normalization and Empirical Mode Decomposition (EMD) for variable speed direct-drive Marine Current Turbine (MCT) system. The method is based on the MCT stator current under the condition of wave and turbulence. The goal of this method is to extract blade imbalance fault feature, which is concealed by the supply frequency and the environment noise. First, a Generalized Likelihood Ratio Test (GLRT) detector is developed and the monitoring variable is selected by analyzing the relationship between the variables. Then, the selected monitoring variable is converted into a time series through data normalization, which makes the imbalance fault characteristic frequency into a constant. At the end, the monitoring variable is filtered out by EMD method to eliminate the effect of turbulence. The experiments show that the proposed method is robust against turbulence through comparing the different fault severities and the different turbulence intensities. Comparison with other methods, the experimental results indicate the feasibility and efficacy of the proposed method. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Instrumental neutron activation analysis as a routine method for rock analysis

International Nuclear Information System (INIS)

Rosenberg, R.J.

1977-06-01

Instrumental neutron activation methods for the analysis of geological samples have been developed. Special emphasis has been laid on the improvement of sensitivity and accuracy in order to maximize tha quality of the analyses. Furthermore, the procedures have been automated as far as possible in order to minimize the cost of the analysis. A short review of the basic literature is given followed by a description of the principles of the method. All aspects concerning the sensitivity are discussed thoroughly in view of the analyst's possibility of influencing them. Experimentally determined detection limits for Na, Al, K, Ca, Sc, Cr, Ti, V, Mn, Fe, Ni, Co, Rb, Zr, Sb, Cs, Ba, La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Yb, Lu, Hf, Ta, Th and U are given. The errors of the method are discussed followed by actions taken to avoid them. The most significant error was caused by flux deviation, but this was avoided by building a rotating sample holder for rotating the samples during irradiation. A scheme for the INAA of 32 elements is proposed. The method has been automated as far as possible and an automatic γ-spectrometer and a computer program for the automatic calculation of the results are described. Furthermore, a completely automated uranium analyzer based on delayed neutron counting is described. The methods are discussed in view of their applicability to rock analysis. It is stated that the sensitivity varies considerably from element to element and instrumental activation analysis is an excellent method for the analysis of some specific elements like lanthanides, thorium and uranium but less so for many other elements. The accuracy is good varying from 2% to 10% for most elements. Instrumental activation analysis for most elements is rather an expensive method there being, however, a few exceptions. The most important of these is uranium. The analysis of uranium by delayed neutron counting is an inexpensive means for the analysis of large numbers of samples needed for

Robust Grid-Current-Feedback Resonance Suppression Method for LCL-Type Grid-Connected Inverter Connected to Weak Grid

DEFF Research Database (Denmark)

Zhou, Xiaoping; Zhou, Leming; Chen, Yandong

2018-01-01

In this paper, a robust grid-current-feedback reso-nance suppression (GCFRS) method for LCL-type grid-connected inverter is proposed to enhance the system damping without introducing the switching noise and eliminate the impact of control delay on system robustness against grid-impedance variation....... It is composed of GCFRS method, the full duty-ratio and zero-beat-lag PWM method, and the lead-grid-current-feedback-resonance-suppression (LGCFRS) method. Firstly, the GCFRS is used to suppress the LCL-resonant peak well and avoid introducing the switching noise. Secondly, the proposed full duty-ratio and zero......-beat-lag PWM method is used to elimi-nate the one-beat-lag computation delay without introducing duty cycle limitations. Moreover, it can also realize the smooth switching from positive to negative half-wave of the grid current and improve the waveform quality. Thirdly, the proposed LGCFRS is used to further...

Comparative Analysis for Robust Penalized Spline Smoothing Methods

Directory of Open Access Journals (Sweden)

Bin Wang

2014-01-01

Full Text Available Smoothing noisy data is commonly encountered in engineering domain, and currently robust penalized regression spline models are perceived to be the most promising methods for coping with this issue, due to their flexibilities in capturing the nonlinear trends in the data and effectively alleviating the disturbance from the outliers. Against such a background, this paper conducts a thoroughly comparative analysis of two popular robust smoothing techniques, the M-type estimator and S-estimation for penalized regression splines, both of which are reelaborated starting from their origins, with their derivation process reformulated and the corresponding algorithms reorganized under a unified framework. Performances of these two estimators are thoroughly evaluated from the aspects of fitting accuracy, robustness, and execution time upon the MATLAB platform. Elaborately comparative experiments demonstrate that robust penalized spline smoothing methods possess the capability of resistance to the noise effect compared with the nonrobust penalized LS spline regression method. Furthermore, the M-estimator exerts stable performance only for the observations with moderate perturbation error, whereas the S-estimator behaves fairly well even for heavily contaminated observations, but consuming more execution time. These findings can be served as guidance to the selection of appropriate approach for smoothing the noisy data.

Probabilistic methods for rotordynamics analysis

Science.gov (United States)

Wu, Y.-T.; Torng, T. Y.; Millwater, H. R.; Fossum, A. F.; Rheinfurth, M. H.

1991-01-01

This paper summarizes the development of the methods and a computer program to compute the probability of instability of dynamic systems that can be represented by a system of second-order ordinary linear differential equations. Two instability criteria based upon the eigenvalues or Routh-Hurwitz test functions are investigated. Computational methods based on a fast probability integration concept and an efficient adaptive importance sampling method are proposed to perform efficient probabilistic analysis. A numerical example is provided to demonstrate the methods.

Thermoelectric Generation Of Current - Theoretical And Experimental Analysis

Science.gov (United States)

Ruciński, Adam; Rusowicz, Artur

2017-12-01

This paper provides some information about thermoelectric technology. Some new materials with improved figures of merit are presented. These materials in Peltier modules make it possible to generate electric current thanks to a temperature difference. The paper indicates possible applications of thermoelectric modules as interesting tools for using various waste heat sources. Some zero-dimensional equations describing the conditions of electric power generation are given. Also, operating parameters of Peltier modules, such as voltage and electric current, are analyzed. The paper shows chosen characteristics of power generation parameters. Then, an experimental stand for ongoing research and experimental measurements are described. The authors consider the resistance of a receiver placed in the electric circuit with thermoelectric elements. Finally, both the analysis of experimental results and conclusions drawn from theoretical findings are presented. Voltage generation of about 1.5 to 2.5 V for the temperature difference from 65 to 85 K was observed when a bismuth telluride thermoelectric couple (traditionally used in cooling technology) was used.

Analysis of methods for quantitative renography

International Nuclear Information System (INIS)

Archambaud, F.; Maksud, P.; Prigent, A.; Perrin-Fayolle, O.

1995-01-01

This article reviews the main methods using renography to estimate renal perfusion indices and to quantify differential and global renal function. The review addresses the pathophysiological significance of estimated parameters according to the underlying models and the choice of the radiopharmaceutical. The dependence of these parameters on the region of interest characteristics and on the methods of background and attenuation corrections are surveyed. Some current recommendations are proposed. (authors). 66 refs., 8 figs

Prospects of Frequency-Time Correlation Analysis for Detecting Pipeline Leaks by Acoustic Emission Method

International Nuclear Information System (INIS)

Faerman, V A; Cheremnov, A G; Avramchuk, V V; Luneva, E E

2014-01-01

In the current work the relevance of nondestructive test method development applied for pipeline leak detection is considered. It was shown that acoustic emission testing is currently one of the most widely spread leak detection methods. The main disadvantage of this method is that it cannot be applied in monitoring long pipeline sections, which in its turn complicates and slows down the inspection of the line pipe sections of main pipelines. The prospects of developing alternative techniques and methods based on the use of the spectral analysis of signals were considered and their possible application in leak detection on the basis of the correlation method was outlined. As an alternative, the time-frequency correlation function calculation is proposed. This function represents the correlation between the spectral components of the analyzed signals. In this work, the technique of time-frequency correlation function calculation is described. The experimental data that demonstrate obvious advantage of the time-frequency correlation function compared to the simple correlation function are presented. The application of the time-frequency correlation function is more effective in suppressing the noise components in the frequency range of the useful signal, which makes maximum of the function more pronounced. The main drawback of application of the time- frequency correlation function analysis in solving leak detection problems is a great number of calculations that may result in a further increase in pipeline time inspection. However, this drawback can be partially reduced by the development and implementation of efficient algorithms (including parallel) of computing the fast Fourier transform using computer central processing unit and graphic processing unit

Modeling and analysis of a novel planar eddy current damper

Science.gov (United States)

Zhang, He; Kou, Baoquan; Jin, Yinxi; Zhang, Lu; Zhang, Hailin; Li, Liyi

2014-05-01

In this paper, a novel 2-DOF permanent magnet planar eddy current damper is proposed, of which the stator is made of a copper plate and the mover is composed of two orthogonal 1-D permanent magnet arrays with a double sided structure. The main objective of the planar eddy current damper is to provide two orthogonal damping forces for dynamic systems like the 2-DOF high precision positioning system. Firstly, the basic structure and the operating principle of the planar damper are introduced. Secondly, the analytical model of the planar damper is established where the magnetic flux density distribution of the permanent magnet arrays is obtained by using the equivalent magnetic charge method and the image method. Then, the analytical expressions of the damping force and damping coefficient are derived. Lastly, to verify the analytical model, the finite element method (FEM) is adopted for calculating the flux density and a planar damper prototype is manufactured and thoroughly tested. The results from FEM and experiments are in good agreement with the ones from the analytical expressions indicating that the analytical model is reasonable and correct.

Minimum current principle and variational method in theory of space charge limited flow

Energy Technology Data Exchange (ETDEWEB)

Rokhlenko, A. [Department of Mathematics, Rutgers University, Piscataway, New Jersey 08854-8019 (United States)

2015-10-21

In spirit of the principle of least action, which means that when a perturbation is applied to a physical system, its reaction is such that it modifies its state to “agree” with the perturbation by “minimal” change of its initial state. In particular, the electron field emission should produce the minimum current consistent with boundary conditions. It can be found theoretically by solving corresponding equations using different techniques. We apply here the variational method for the current calculation, which can be quite effective even when involving a short set of trial functions. The approach to a better result can be monitored by the total current that should decrease when we on the right track. Here, we present only an illustration for simple geometries of devices with the electron flow. The development of these methods can be useful when the emitter and/or anode shapes make difficult the use of standard approaches. Though direct numerical calculations including particle-in-cell technique are very effective, but theoretical calculations can provide an important insight for understanding general features of flow formation and even sometimes be realized by simpler routines.

Analysis methods (from 301 to 351)

International Nuclear Information System (INIS)

Analysis methods of materials used in the nuclear field (uranium, plutonium and their compounds, zirconium, magnesium, water...) and determination of impurities. Only reliable methods are selected [fr

Condition monitoring of machinery using motor current signature analysis

International Nuclear Information System (INIS)

Kryter, R.C.; Haynes, H.D.

1989-01-01

Motor current signature analysis (MCSA) is a powerful monitoring tool for motor-driven equipment that provides a nonintrusive means for detecting the presence of mechanical and electrical abnormalities in the motor and the driven equipment, including altered conditions in the process ''downstream'' of the motor-driven equipment. It was developed at the Oak Ridge National Laboratory as a means for determining the effects of aging and service wear systems, but it is applicable to a broad range of machinery. MCSA is based on the recognition that an electric motor (ac or dc) driving a mechanical load acts as an efficient and permanently available transducer by sensing mechanical load variations, large and small, long-term and rapid, and converting them into variations in the induced current generated in the motor windings. These motor current variations are carried by the electrical cables processes as desired. Motor current signatures, obtained in both time and over time to provide early indication of degradation. Successful applications of MCSA technology (patent applied for) include not only motor-operated valves but also pumps of various designs, blowers, and air conditioning systems. Examples are presented briefly, and speculation regarding the applicability of MCSA to a broader range of equipment monitoring and production line testing is also given. 1 ref., 13 figs

A sensorless control method for capacitor voltage balance and circulating current suppression of modular multilevel converter

DEFF Research Database (Denmark)

Liu, Hui; Ma, Ke; Loh, Poh Chiang

2015-01-01

There are several problems in the Modular Multilevel Converter (MMC), such as the appearance of circulating current, capacitor voltage unbalance and the requirement for a high number of sensors. All these problems will decrease the reliability and raise the cost/uncertainty of using MMC solutions....... As a result, a sensorless control method is proposed in this paper, which targets to improve the performances of MMC in respect to the above mentioned disadvantages: To decrease the cost and simplify the physical implementation, a state observer is proposed and designed to estimate both the capacitor voltages...... and the circulating currents in order to replace the high numbers of sensors. Furthermore, a control method combining the circulating current suppression and the capacitor voltage balancing is conducted based on the proposed state observer. It is concluded that the proposed state observer and control method can...

Novel method to control antenna currents based on theory of characteristic modes

Science.gov (United States)

Elghannai, Ezdeen Ahmed

Characteristic Mode Theory is one of the very few numerical methods that provide a great deal of physical insight because it allows us to determine the natural modes of the radiating structure. The key feature of these modes is that the total induced antenna current, input impedance/admittance and radiation pattern can be expressed as a linear weighted combination of individual modes. Using this decomposition method, it is possible to study the behavior of the individual modes, understand them and therefore control the antennas behavior; in other words, control the currents induced on the antenna structure. This dissertation advances the topic of antenna design by carefully controlling the antenna currents over the desired frequency band to achieve the desired performance specifications for a set of constraints. Here, a systematic method based on the Theory of Characteristic Modes (CM) and lumped reactive loading to achieve the goal of current control is developed. The lumped reactive loads are determined based on the desired behavior of the antenna currents. This technique can also be used to impedance match the antenna to the source/generator connected to it. The technique is much more general than the traditional impedance matching. Generally, the reactive loads that properly control the currents exhibit a combination of Foster and non-Foster behavior. The former can be implemented with lumped passive reactive components, while the latter can be implemented with lumped non-Foster circuits (NFC). The concept of current control is applied to design antennas with a wide band (impedance/pattern) behavior using reactive loads. We successfully applied this novel technique to design multi band and wide band antennas for wireless applications. The technique was developed to match the antenna to resistive and/or complex source impedance and control the radiation pattern at these frequency bands, considering size and volume constraints. A wide band patch antenna was

CURRENT STATE AND EVOLUTION PERSPECTIVES FOR MANAGEMENT ACCOUNTING IN THE ENERGY SECTOR BY IMPLEMENTING THE ABC METHOD

Directory of Open Access Journals (Sweden)

Rof Letitia Maria

2011-07-01

Full Text Available Based on a controversial issue, namely determining and controlling costs in the energy sector, the present study falls within the scope of management accounting and control. This scientific approach was initiated as a result of personal research concerns in the area of accounting, starting from the need to know and quantify costs in a sector of the economy that is less exploited. The main objective of this scientific approach is to address the evolution of the energy sector in a national and international context, in terms of economy and finances, with the aim to underline the need to organize and conduct management accounting in this sector. We will present a few particularities of the energy system, the current status of implementation of a medium and long term strategy aimed at developing the energy sector, as well as the need to adopt modern costing methods in this sector, which ensure operative cost control and performance growth of the entities that operate in this sector. Information on the reviewed topic was conducted by studying the national and international literature in the field, by analyzing the associated legislation, by consulting specialized web-sites and various articles in the database. The main research methods used in this scientific approach were analysis and synthesis, and qualitative research was the type of used research. The results of the research will materialize in providing the necessary conditions for designing an econometric model for implementing the ABC method, the conceptual and ideological delimitation of the ABC method, the deepening of the positive and negative aspects that the implementation of the Activity Based Costing involves. The major implication for the researched field is ensuring success for the implementation of a modern costing method in the energy sector, underlining the shortcomings of the traditional costing methods. The added value of the paper consists in conducting a rigorous study of the