Triple voltage dc-to-dc converter and method
Su, Gui-Jia
2008-08-05
A circuit and method of providing three dc voltage buses and transforming power between a low voltage dc converter and a high voltage dc converter, by coupling a primary dc power circuit and a secondary dc power circuit through an isolation transformer; providing the gating signals to power semiconductor switches in the primary and secondary circuits to control power flow between the primary and secondary circuits and by controlling a phase shift between the primary voltage and the secondary voltage. The primary dc power circuit and the secondary dc power circuit each further comprising at least two tank capacitances arranged in series as a tank leg, at least two resonant switching devices arranged in series with each other and arranged in parallel with the tank leg, and at least one voltage source arranged in parallel with the tank leg and the resonant switching devices, said resonant switching devices including power semiconductor switches that are operated by gating signals. Additional embodiments having a center-tapped battery on the low voltage side and a plurality of modules on both the low voltage side and the high voltage side are also disclosed for the purpose of reducing ripple current and for reducing the size of the components.
Center for Applied Linguistics, Washington DC, USA
Sugarman, Julie; Fee, Molly; Donovan, Anne
2015-01-01
The Center for Applied Linguistics (CAL) is a private, nonprofit organization with over 50 years' experience in the application of research on language and culture to educational and societal concerns. CAL carries out its mission to improve communication through better understanding of language and culture by engaging in a variety of projects in…
FUNCTIONAL CORRELATION OF FP AND DC METHODS
Directory of Open Access Journals (Sweden)
Marin Kaluža
2013-02-01
Full Text Available Most of organizations today use information-communication technologies (ICT for building an information system (IS. IS is assembled of hardware, software, network resources, organizational and human resources. In IS development process, complexity is crucial for evaluating quantities of resources needed (time, people, money, equipment. Complexity of an IS can be evaluated and/or measured in different phases of development. There are many methods for measuring complexity, but mostly used and thoroughly described method is Function Point Analysis (FP. The opposite method, Database Complexity (DC, does not measure all the aspects of IS, but it could evaluate system complexity depending on the database complexity. DC method is intended to be used for measuring semantic complexity of the IS database, and can be shown by counting attributes A and foreign keys F. This paper describes a very high correlation between FP and DC methods, and defines a function which can in 95% of accuracy express FP values from measured DC values.
DC-Link Compensation Method for Slim DC Link Drives Fed by Soft Grid
DEFF Research Database (Denmark)
Mathe, Laszlo; Rosendahl Andersen, Henrik; Lazar, Radu
2010-01-01
Slim DC-link PWM (AC) drives for lowperformance applications are emerging on the market. Such drives equipped with a small DC-link capacitance exhibit instability tendencies, if installed on a soft line, giving a degraded performance. The total harmonic distortion (THD) and the partially weighted...... method, which ensures the stability of the slim DC-link on a soft grid. The proposed compensation method may be used for open- and closedloop control schemes, requiring a small overhead in the digital implementation....
Directory of Open Access Journals (Sweden)
M. Khalilzadeh
2016-12-01
Full Text Available In this paper, a stochastic approach is proposed for reliability assessment of bidirectional DC-DC converters, including the fault-tolerant ones. This type of converters can be used in a smart DC grid, feeding DC loads such as home appliances and plug-in hybrid electric vehicles (PHEVs. The reliability of bidirectional DC-DC converters is of such an importance, due to the key role of the expected increasingly utilization of DC grids in modern Smart Grid. Markov processes are suggested for reliability modeling and consequently calculating the expected effective lifetime of bidirectional converters. A three-leg bidirectional interleaved converter using data of Toyota Prius 2012 hybrid electric vehicle is used as a case study. Besides, the influence of environment and ambient temperature on converter lifetime is studied. The impact of modeling the reliability of the converter and adding reliability constraints on the technical design procedure of the converter is also investigated. In order to investigate the effect of leg increase on the lifetime of the converter, single leg to five-leg interleave DC-DC converters are studied considering economical aspect and the results are extrapolated for six and seven-leg converters. The proposed method could be generalized so that the number of legs and input and output capacitors could be an arbitrary number.
Applied nonparametric statistical methods
Sprent, Peter
2007-01-01
While preserving the clear, accessible style of previous editions, Applied Nonparametric Statistical Methods, Fourth Edition reflects the latest developments in computer-intensive methods that deal with intractable analytical problems and unwieldy data sets. Reorganized and with additional material, this edition begins with a brief summary of some relevant general statistical concepts and an introduction to basic ideas of nonparametric or distribution-free methods. Designed experiments, including those with factorial treatment structures, are now the focus of an entire chapter. The text also e
Schoenfeld, A. D.; Yu, Y.
1973-01-01
Versatile standardized pulse modulation nondissipatively regulated control signal processing circuits were applied to three most commonly used dc to dc power converter configurations: (1) the series switching buck-regulator, (2) the pulse modulated parallel inverter, and (3) the buck-boost converter. The unique control concept and the commonality of control functions for all switching regulators have resulted in improved static and dynamic performance and control circuit standardization. New power-circuit technology was also applied to enhance reliability and to achieve optimum weight and efficiency.
Application of DC gradient sounding method
International Nuclear Information System (INIS)
Xie Hongrong
2010-01-01
Based on the thought of new observation and reverse method of electronic measuring in deep section proposed by professor Ge Zhongwei, three-pole gradient sound(GS-3A, GS-3B)distribution and observations are applied in mining practice. By changing the work flow and distributing the electronic measurement deep section by some distance, several reception equipments are used in multiple points observations using multiple points-one string continuous observation of electronic differences and polarization. Practices prove that this effective method is suit to two dimensions calculation and ration explanation in electronic sounding of numerical simulate grids. This method is accurate and effects well in geology work. (authors)
Applied Bayesian hierarchical methods
National Research Council Canada - National Science Library
Congdon, P
2010-01-01
... . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 Posterior Inference from Bayes Formula . . . . . . . . . . . . 1.3 Markov Chain Monte Carlo Sampling in Relation to Monte Carlo Methods: Obtaining Posterior...
Methods of applied mathematics
Hildebrand, Francis B
1992-01-01
This invaluable book offers engineers and physicists working knowledge of a number of mathematical facts and techniques not commonly treated in courses in advanced calculus, but nevertheless extremely useful when applied to typical problems in many different fields. It deals principally with linear algebraic equations, quadratic and Hermitian forms, operations with vectors and matrices, the calculus of variations, and the formulations and theory of linear integral equations. Annotated problems and exercises accompany each chapter.
Long-lasting increase in axonal excitability after epidurally applied DC.
Jankowska, Elzbieta; Kaczmarek, Dominik; Bolzoni, Francesco; Hammar, Ingela
2017-08-01
Effects of direct current (DC) on nerve fibers have primarily been investigated during or just after DC application. However, locally applied cathodal DC was recently demonstrated to increase the excitability of intraspinal preterminal axonal branches for >1 h. The aim of this study was therefore to investigate whether DC evokes a similarly long-lasting increase in the excitability of myelinated axons within the dorsal columns. The excitability of dorsal column fibers stimulated epidurally was monitored by recording compound action potentials in peripheral nerves in acute experiments in deeply anesthetized rats. The results show that 1 ) cathodal polarization (0.8-1.0 µA) results in a severalfold increase in the number of epidurally activated fibers and 2 ) the increase in the excitability appears within seconds, 3 ) lasts for >1 h, and 4 ) is activity independent, as it does not require fiber stimulation during the polarization. These features demonstrate an unexplored form of plasticity of myelinated fibers and indicate the conditions under which it develops. They also suggest that therapeutic effects of epidural stimulation may be significantly enhanced if it is combined with DC polarization. In particular, by using DC to increase the number of fibers activated by low-intensity epidural stimuli, the low clinical tolerance to higher stimulus intensities might be overcome. The activity independence of long-lasting DC effects would also allow the use of only brief periods of DC polarization preceding epidural stimulation to increase the effect. NEW & NOTEWORTHY The study indicates a new form of plasticity of myelinated fibers. The differences in time course of DC-evoked increases in the excitability of myelinated nerve fibers in the dorsal columns and in preterminal axonal branches suggest that distinct mechanisms are involved in them. The results show that combining epidural stimulation and transspinal DC polarization may dramatically improve their outcome and
DC to DC power converters and methods of controlling the same
Steigerwald, Robert Louis; Elasser, Ahmed; Sabate, Juan Antonio; Todorovic, Maja Harfman; Agamy, Mohammed
2012-12-11
A power generation system configured to provide direct current (DC) power to a DC link is described. The system includes a first power generation unit configured to output DC power. The system also includes a first DC to DC converter comprising an input section and an output section. The output section of the first DC to DC converter is coupled in series with the first power generation unit. The first DC to DC converter is configured to process a first portion of the DC power output by the first power generation unit and to provide an unprocessed second portion of the DC power output of the first power generation unit to the output section.
Effect of applied DC electric fields in flame spread over polyethylene-coated electrical wire
Jin, Young Kyu
2011-03-01
We experimentally investigated the effect of applied DC electric fields on the flame spread over polyethylene-coated electrical wire. The flame-spread rates over electrical wire with negative and positive DC electric fields from 0 to ±7 kV were measured and analyzed. We compared the results for DC electric fields with previous results for AC electric fields. We explored whether or not various flame shapes could be obtained with DC electric fields and the main reason for the flame-spread acceleration, particularly at the end of the electrical wire, for AC electric fields. We found that DC electric fields do not significantly affect the flame-spread rates. However, the flame shape is mildly altered by the ionic wind effect even for DC electric fields. The flame-spread rate is relevant to the flame shape and the slanted direction in spite of the mild impact. A possible explanation for the flame spread is given by a thermal-balance mechanism and fuel-vapor jet. © 2011 The Korean Society of Mechanical Engineers.
DC potential drop method for evaluating material degradation
International Nuclear Information System (INIS)
Seok, Chang Sung; Bae, Bong Kook; Koo, Jae Mean
2004-01-01
The remaining life estimation for the aged components in power plants as well as chemical plants are very important because mechanical properties of the components are degraded with in-service exposure time in high temperatures. Since it is difficult to take specimens from the operating components to evaluate mechanical properties of components, nondestructive techniques are needed to evaluate the degradation. In this study, test materials with several different degradation levels were prepared by isothermal aging heat treatment at 630 .deg. C. The DC potential drop method and destructive methods such as tensile and fracture toughness were used in order to evaluate the degradation of 1Cr-1Mo-0.25V steels. In this result, we can see that tensile strength and fracture toughness can be calculated from resistivity and it is possible to evaluate material degradation using DC potential drop method, non-destructive method
DLC Films Deposited by the DC PACVD Method
Directory of Open Access Journals (Sweden)
D. Palamarchuk
2003-01-01
Full Text Available DLC (Diamond-Like Carbon coatings have been suggested as protective surface layers against wear. However hard DLC coatings, especially those of greater thickness, have poor adhesion to substrates. We have used several ways to increase the adhesion of DLC coatings prepared by the PACVD (Plasma Assisted Chemical Vapour Deposition method on steel substrates. One of these is the DC PACVD method for preparing DLC films.
DLC Films Deposited by the DC PACVD Method
D. Palamarchuk; M. Zoriy; J. Gurovič; F. Černý; S. Konvičková; I. Hüttel
2003-01-01
DLC (Diamond-Like Carbon) coatings have been suggested as protective surface layers against wear. However hard DLC coatings, especially those of greater thickness, have poor adhesion to substrates. We have used several ways to increase the adhesion of DLC coatings prepared by the PACVD (Plasma Assisted Chemical Vapour Deposition) method on steel substrates. One of these is the DC PACVD method for preparing DLC films.
Circuit and Method for Communication Over DC Power Line
Krasowski, Michael J.; Prokop, Norman F.
2007-01-01
A circuit and method for transmitting and receiving on-off-keyed (OOK) signals with fractional signal-to-noise ratios uses available high-temperature silicon- on-insulator (SOI) components to move computational, sensing, and actuation abilities closer to high-temperature or high-ionizing radiation environments such as vehicle engine compartments, deep-hole drilling environments, industrial control and monitoring of processes like smelting, and operations near nuclear reactors and in space. This device allows for the networking of multiple, like nodes to each other and to a central processor. It can do this with nothing more than the already in-situ power wiring of the system. The device s microprocessor allows it to make intelligent decisions within the vehicle operational loop and to effect control outputs to its associated actuators. The figure illustrates how each node converts digital serial data to OOK 18-kHz in transmit mode and vice-versa in receive mode; though operations at lower frequencies or up to a megahertz are within reason using this method and these parts. This innovation s technique modulates a DC power bus with millivolt-level signals through a MOSFET (metal oxide semiconductor field effect transistor) and resistor by OOK. It receives and demodulates this signal from the DC power bus through capacitive coupling at high temperature and in high ionizing radiation environments. The demodulation of the OOK signal is accomplished by using an asynchronous quadrature detection technique realized by a quasi-discrete Fourier transform through use of the quadrature components (0 and 90 phases) of the carrier frequency as generated by the microcontroller and as a function of the selected crystal frequency driving its oscillator. The detected signal is rectified using an absolute-value circuit containing no diodes (diodes being non-operational at high temperatures), and only operational amplifiers. The absolute values of the two phases of the received signal
3D DC Resistivity Inversion with Topography Based on Regularized Conjugate Gradient Method
Directory of Open Access Journals (Sweden)
Jian-ke Qiang
2013-01-01
Full Text Available During the past decades, we observed a strong interest in 3D DC resistivity inversion and imaging with complex topography. In this paper, we implemented 3D DC resistivity inversion based on regularized conjugate gradient method with FEM. The Fréchet derivative is assembled with the electric potential in order to speed up the inversion process based on the reciprocity theorem. In this study, we also analyzed the sensitivity of the electric potential on the earth’s surface to the conductivity in each cell underground and introduced an optimized weighting function to produce new sensitivity matrix. The synthetic model study shows that this optimized weighting function is helpful to improve the resolution of deep anomaly. By incorporating topography into inversion, the artificial anomaly which is actually caused by topography can be eliminated. As a result, this algorithm potentially can be applied to process the DC resistivity data collected in mountain area. Our synthetic model study also shows that the convergence and computation speed are very stable and fast.
Characterization and gas sensing properties of CuO synthesized by DC directly applying voltage
Energy Technology Data Exchange (ETDEWEB)
Klinbumrung, Arrak [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongtem, Titipun [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongtem, Somchai, E-mail: schthongtem@yahoo.com [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)
2014-09-15
Highlights: • CuO as a p-type semiconductor. • It was synthesized by directly applying voltage. • A promising material for ammonia detection. - Abstract: CuO microstructure was successfully synthesized by 50 A and 3.6 V DC directly applying voltage. Crystalline structure was characterized by X-ray diffraction (XRD), morphology by scanning and transmission electron microscopy (SEM, TEM). The sample of the 15 min processing time has an irregular shape with diameter about several hundreds of nanometer. Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible (UV–vis) absorption spectroscopy and photoluminescence (PL) were used to determine vibrational modes and optical properties of the as-synthesized samples: 529 and 585 cm{sup −1} vibrational modes, 3.95 eV band gap, and 402 nm emitting wavelength in violet region of CuO. X-ray photoelectron (XPS) spectroscopy was used to determine chemical composition, Cu(II)O, of the metal oxide surface. Gas sensing performance exposing to NH{sub 3} mixed with air at various working temperatures and NH{sub 3} concentrations of the as-synthesized CuO has the best response at the optimal working temperature of 250 °C: sensitivity of 56.6% exposed to 5275 ppm NH{sub 3}.
Five-Level Converter with Low Switching Frequency Applied as DC Voltage Supply
DEFF Research Database (Denmark)
Rasmussen, Tonny Wederberg
1999-01-01
This paper describes the use of a multi-level converter as a DC supply. Equations for the converter will be deduced in the nondissipative case. The equations provide solutions to DC voltage and the angle of converter voltage. In addition the spectrum for the harmonics after the elimination...... of selected harmonics will be shown. Finally measurements on a practical laboratory model are shown....
Applied Formal Methods for Elections
DEFF Research Database (Denmark)
Wang, Jian
development time, or second dynamically, i.e. monitoring while an implementation is used during an election, or after the election is over, for forensic analysis. This thesis contains two chapters on this subject: the chapter Analyzing Implementations of Election Technologies describes a technique...... process. The chapter Measuring Voter Lines describes an automated data collection method for measuring voters' waiting time, and discusses statistical models designed to provide an understanding of the voter behavior in polling stations....
Active Damping Control Methods for Three-Phase Slim DC-link Drive System
DEFF Research Database (Denmark)
Yang, Feng; Wang, Dong; Blaabjerg, Frede
2017-01-01
In the conventional variable speed drive, the dclink including the dc-choke and electrolytic capacitor is bulky with limited lifetime. The slim dc-link drive is thus proposed for the lower cost and longer lifetime by using the film capacitor to replace the electrolytic capacitor and dc......-choke. However, such drive system suffers from the potential instability issue, due to the negative incremental impedance characteristic caused by the constant power load behavior of the motor drive system, and the influence by the reduced capacitance. Therefore, active damping methods are very important...... for stabilizing such slim dc-link drives together with the benefit of low cost and high flexibility. This paper gives an overview of the state-of-the-art active damping methods for the three-phase slim dc-link drive. The main pros and cons of each method are identified. The theoretical comparison is validated...
Applied Formal Methods for Elections
DEFF Research Database (Denmark)
Wang, Jian
Information technology is changing the way elections are organized. Technology renders the electoral process more efficient, but things could also go wrong: Voting software is complex, it consists of over thousands of lines of code, which makes it error-prone. Technical problems may cause delays ...... process. The chapter Measuring Voter Lines describes an automated data collection method for measuring voters' waiting time, and discusses statistical models designed to provide an understanding of the voter behavior in polling stations....... at polling stations, or even delay the announcement of the final result. This thesis describes a set of methods to be used, for example, by system developers, administrators, or decision makers to examine election technologies, social choice algorithms and voter experience. Technology: Verifiability refers...... development time, or second dynamically, i.e. monitoring while an implementation is used during an election, or after the election is over, for forensic analysis. This thesis contains two chapters on this subject: the chapter Analyzing Implementations of Election Technologies describes a technique...
Measurement of fatigue crack propagation at -700C with the d.c. potential probe method
International Nuclear Information System (INIS)
Siekmann, G.; Berns, H.
1983-01-01
Measurement of fatigue crack propagation by means of the d.c. potential probe on 1/2''CT specimens at 20 0 C and -70 0 C is described. The method proves to be a useful tool for the determination of fatigue crack propagation if the experiments have to be carried out in temperature baths or temperature chambers. At 20 deg C the comparison of the optical method of crack growth measurement with the d.c. potential probe method gives calibration curves which, accounting for several parameters of influence, from the basis of crack propagation measurements with the d.c. potential probe method at -70 0 C. (orig.) [de
A long-term validation of the modernised DC-ARC-OES solid-sample method
Energy Technology Data Exchange (ETDEWEB)
Florian, K. [Dept. of Chemistry, Technical University of Kosice (Slovakia); Hassler, J.; Foerster, O. [Elektroschmelzwerk GmbH, Kempten (Germany)
2001-12-01
The validation procedure based on ISO 17 025 standard has been used to study and illustrate both the long-term stability of the calibration process of the DC-ARC solid sample spectrometric method and the main validation criteria of the method. In the calculation of the validation characteristics depending on the linearity(calibration), also the fulfilment of predetermining criteria such as normality and homoscedasticity was checked. In order to decide whether there are any trends in the time-variation of the analytical signal or not, also the Neumann test of trend was applied and evaluated. Finally, a comparison with similar validation data of the ETV-ICP-OES method was carried out. (orig.)
Bayesian methods applied to GWAS.
Fernando, Rohan L; Garrick, Dorian
2013-01-01
Bayesian multiple-regression methods are being successfully used for genomic prediction and selection. These regression models simultaneously fit many more markers than the number of observations available for the analysis. Thus, the Bayes theorem is used to combine prior beliefs of marker effects, which are expressed in terms of prior distributions, with information from data for inference. Often, the analyses are too complex for closed-form solutions and Markov chain Monte Carlo (MCMC) sampling is used to draw inferences from posterior distributions. This chapter describes how these Bayesian multiple-regression analyses can be used for GWAS. In most GWAS, false positives are controlled by limiting the genome-wise error rate, which is the probability of one or more false-positive results, to a small value. As the number of test in GWAS is very large, this results in very low power. Here we show how in Bayesian GWAS false positives can be controlled by limiting the proportion of false-positive results among all positives to some small value. The advantage of this approach is that the power of detecting associations is not inversely related to the number of markers.
Su, Gui-Jia
2003-06-10
A multilevel DC link inverter and method for improving torque response and current regulation in permanent magnet motors and switched reluctance motors having a low inductance includes a plurality of voltage controlled cells connected in series for applying a resulting dc voltage comprised of one or more incremental dc voltages. The cells are provided with switches for increasing the resulting applied dc voltage as speed and back EMF increase, while limiting the voltage that is applied to the commutation switches to perform PWM or dc voltage stepping functions, so as to limit current ripple in the stator windings below an acceptable level, typically 5%. Several embodiments are disclosed including inverters using IGBT's, inverters using thyristors. All of the inverters are operable in both motoring and regenerating modes.
Three dimensional finite element methods: Their role in the design of DC accelerator systems
Energy Technology Data Exchange (ETDEWEB)
Podaru, Nicolae C.; Gottdang, A.; Mous, D. J. W. [High Voltage Engineering Europa B.V., P.O. Box 99, 3800 AB, Amersfoort (Netherlands)
2013-04-19
High Voltage Engineering has designed, built and tested a 2 MV dual irradiation system that will be applied for radiation damage studies and ion beam material modification. The system consists of two independent accelerators which support simultaneous proton and electron irradiation (energy range 100 keV - 2 MeV) of target sizes of up to 300 Multiplication-Sign 300 mm{sup 2}. Three dimensional finite element methods were used in the design of various parts of the system. The electrostatic solver was used to quantify essential parameters of the solid-state power supply generating the DC high voltage. The magnetostatic solver and ray tracing were used to optimize the electron/ion beam transport. Close agreement between design and measurements of the accelerator characteristics as well as beam performance indicate the usefulness of three dimensional finite element methods during accelerator system design.
DEFF Research Database (Denmark)
Kwon, Jun Bum; Wang, Xiongfei; Blaabjerg, Frede
2017-01-01
. Through this method, the required computation time and CPU memory can be reduced, where this faster simulation can be an advantage of a large network simulation. Besides, the achieved results show the same results as the non-linear time-domain simulation. Furthermore, the HSS modeling can describe how...... with different switching frequency or harmonics from ac-dc converters makes that harmonics and frequency coupling are both problems of ac system and challenges of dc system. This paper presents a modeling and simulation method for a large dc power electronic system by using Harmonic State Space (HSS) modeling...
Hybrid Droop Control Strategy Applied to Grid-Supporting Converters in DC Microgrids
DEFF Research Database (Denmark)
Han, Renke; Meng, Lexuan; Guerrero, Josep M.
2017-01-01
The paper proposes a hybrid droop control strategy to enhance the stability and increase maximum constant power loads (CPLs) capability of DC microgrids in a realistic scenario. By capturing the detailed model of inner control loops and hybrid droop control and general dc MG topology, a thorough...... comparative study is conducted between traditional droop control and hybrid droop control. Enhanced control bandwidth and system stability margin are shown to illustrate the advantages of the proposal. CPL penetration is one of the critical consideration of this paper. The hybrid droop control can increase...
Efficiency of particle swarm optimization applied on fuzzy logic DC motor speed control
Directory of Open Access Journals (Sweden)
Allaoua Boumediene
2008-01-01
Full Text Available This paper presents the application of Fuzzy Logic for DC motor speed control using Particle Swarm Optimization (PSO. Firstly, the controller designed according to Fuzzy Logic rules is such that the systems are fundamentally robust. Secondly, the Fuzzy Logic controller (FLC used earlier was optimized with PSO so as to obtain optimal adjustment of the membership functions only. Finally, the FLC is completely optimized by Swarm Intelligence Algorithms. Digital simulation results demonstrate that in comparison with the FLC the designed FLC-PSO speed controller obtains better dynamic behavior and superior performance of the DC motor, as well as perfect speed tracking with no overshoot.
Directory of Open Access Journals (Sweden)
Boumediène Allaoua
2013-01-01
Full Text Available The development of electric vehicles power electronics system control comprising of DC-AC inverters and DC-DC converters takes a great interest of researchers in the modern industry. A DC-AC inverter supplies the high power electric vehicle motors torques of the propulsion system and utility loads, whereas a DC-DC converter supplies conventional low-power, low-voltage loads. However, the need for high power bidirectional DC-DC converters in future electric vehicles has led to the development of many new topologies of DC-DC converters. Nonlinear control of power converters is an active area of research in the fields of power electronics. This paper focuses on a fuzzy sliding mode strategy (FSMS as a control strategy for boost DC-DC converter power supply for electric vehicle. The proposed fuzzy controller specifies changes in the control signal based on the surface and the surface change knowledge to satisfy the sliding mode stability and attraction conditions. The performances of the proposed fuzzy sliding controller are compared to those obtained by a classical sliding mode controller. The satisfactory simulation results show the efficiency of the proposed control law which reduces the chattering phenomenon. Moreover, the obtained results prove the robustness of the proposed control law against variation of the load resistance and the input voltage of the studied converter.
Electron kinetics in weakly ionized helium under DC and HF applied electric fields
Energy Technology Data Exchange (ETDEWEB)
Alves, L.L.; Ferreira, C.M. (Instituto Superior Tecnico, Lisbon (Portugal). Centro de Electrodinamica)
1991-04-14
The electron kinetics in weakly ionized helium under the action of direct current (DC) and high frequency (HF) fields of angular frequency {omega} is investigated by solving the homogeneous electron Boltzmann equation using the classical two-term expansion approximation. The analysis is based on a consistent set of electron cross sections which is here derived by adjusting experimental cross section data in such a way that calculated and measured electron swarm parameters are in agreement. In the case of HF fields the analysis is based on the DC effective field approximation which is valid for {omega} > tau{sub e}{sup -1}, where tau{sub e} is the characteristic time for electron energy relaxation by collisions with the atoms. The influence of {omega} on the electron energy distribution function, transport parameters, rate coefficients and fractional power transfer is investigated and a detailed comparison of the DC and HF situations is made. It is shown that for reduced effective fields in the range 10{sup -16}-10{sup -15} V cm{sup 2}, as typically found in low-pressure discharges, the mean electron kinetic properties are nearly the same in the whole range of {omega} > tau{sub e}{sup -1} as for the DC case. (author).
System and Method for Determining Rate of Rotation Using Brushless DC Motor
Howard, David E. (Inventor); Smith, Dennis A. (Inventor)
2000-01-01
A system and method are provided for measuring rate of rotation. A brushless DC motor is rotated and produces a back electromagnetic force (emf) on each winding thereof. Each winding's back-emf is squared. The squared outputs associated with each winding are combined, with the square root being taken of such combination, to produce a DC output proportional only to the rate of rotation of the motor's shaft.
A new method for speed control of a DC motor using magnetorheological clutch
Nguyen, Quoc Hung; Choi, Seung-Bok
2014-03-01
In this research, a new method to control speed of DC motor using magnetorheological (MR) clutch is proposed and realized. Firstly, the strategy of a DC motor speed control using MR clutch is proposed. The MR clutch configuration is then proposed and analyzed based on Bingham-plastic rheological model of MR fluid. An optimal designed of the MR clutch is then studied to find out the optimal geometric dimensions of the clutch that can transform a required torque with minimum mass. A prototype of the optimized MR clutch is then manufactured and its performance characteristics are experimentally investigated. A DC motor speed control system featuring the optimized MR clutch is designed and manufactured. A PID controller is then designed to control the output speed of the system. In order to evaluate the effectiveness of the proposed DC motor speed control system, experimental results of the system such as speed tracking performance are obtained and presented with discussions.
DEFF Research Database (Denmark)
Xu, Fengda; Guo, Qinglai; Sun, Hongbin
2015-01-01
For an AC/DC coupled transmission system, the change of transmission power on the DC lines will significantly influence the AC systems’ voltage. This paper describes a method to coordinated control the reactive power of power plants and shunt capacitors at DC converter stations nearby, in order...
Wind tunnel investigation of active controls technology applied to a DC-10 derivative
Winther, B. A.; Shirley, W. A.; Heimbaugh, R. M.
1980-01-01
Application of active controls technology to reduce aeroelastic response offers a potential for significant payoffs in terms of aerodynamic efficiency and structural weight. As part of the NASA Energy Efficient Transport program, the impact upon flutter and gust load characteristics has been investigated by means of analysis and low-speed wind tunnel tests of a semispan model. The model represents a DC-10 derivative with increased wing span and an active aileron surface, responding to vertical acceleration at the wing tip. A control law satisfying both flutter and gust load constraints is presented and evaluated. In general, the beneficial effects predicted by analysis are in good agreement with experimental data.
DEFF Research Database (Denmark)
Høskuldsson, Agnar
2008-01-01
The author has developed a framework for mathematical modelling within applied sciences. It is characteristic for data from 'nature and industry' that they have reduced rank for inference. It means that full rank solutions normally do not give satisfactory solutions. The basic idea of H...... with finding a balance between the estimation task and the prediction task. The name H-methods has been chosen because of close analogy with the Heisenberg uncertainty inequality. A similar situation is present in modelling data. The mathematical modelling stops, when the prediction aspect of the model cannot...... be improved. H-methods have been applied to wide range of fields within applied sciences. In each case, the H-methods provide with superior solutions compared to the traditional ones. A background for the H-methods is presented. The H-principle of mathematical modelling is explained. It is shown how...
Mendrek, M. J.; Higgins, R. H.; Danford, M. D.
1988-01-01
To investigate metal surface corrosion and the breakdown of metal protective coatings, the ac impedance method is applied to six systems of primer coated and primer topcoated 4130 steel. Two primers were used: a zinc-rich epoxy primer and a red lead oxide epoxy primer. The epoxy-polyamine topcoat was used in four of the systems. The EG and G-PARC Model 368 ac impedance measurement system, along with dc measurements with the same system using the polarization resistance method, were used to monitor changing properties of coated 4230 steel disks immersed in 3.5 percent NaCl solutions buffered at pH 5.4 over periods of 40 to 60 days. The corrosion system can be represented by an electronic analog called an equivalent circuit consisting of resistors and capacitors in specific arrangements. This equivalent circuit parallels the impedance behavior of the corrosion system during a frequency scan. Values for the resistors and capacitors, that can be assigned in the equivalent circuit following a least-squares analysis of the data, describe changes that occur on the corroding metal surface and in the protective coatings. Two equivalent circuits have been determined that predict the correct Bode phase and magnitude of the experimental sample at different immersion times. The dc corrosion current density data are related to equivalent circuit element parameters. Methods for determining corrosion rate with ac impedance parameters are verified by the dc method.
[Montessori method applied to dementia - literature review].
Brandão, Daniela Filipa Soares; Martín, José Ignacio
2012-06-01
The Montessori method was initially applied to children, but now it has also been applied to people with dementia. The purpose of this study is to systematically review the research on the effectiveness of this method using Medical Literature Analysis and Retrieval System Online (Medline) with the keywords dementia and Montessori method. We selected lo studies, in which there were significant improvements in participation and constructive engagement, and reduction of negative affects and passive engagement. Nevertheless, systematic reviews about this non-pharmacological intervention in dementia rate this method as weak in terms of effectiveness. This apparent discrepancy can be explained because the Montessori method may have, in fact, a small influence on dimensions such as behavioral problems, or because there is no research about this method with high levels of control, such as the presence of several control groups or a double-blind study.
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 ‘...
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 ...
SoC-Based Droop Method for Distributed Energy Storage in DC Microgrid Applications
DEFF Research Database (Denmark)
Lu, Xiaonan; Sun, Kai; Guerrero, Josep M.
2012-01-01
With the progress of distributed generation nowadays, microgrid is employed to integrate different renewable energy sources into a certain area. For several kinds of renewable sources have DC outputs, DC microgrid has drawn more attention recently. Meanwhile, to deal with the uncertainty...... in the output of microgrid system, distributed energy storage is usually adopted. Considering that the state-of-charge (SoC) of each battery may not be the same, decentralized droop control method based on SoC is shown in this paper to reach proportional load power sharing. With this method, the battery...
Modeling and Simulation of DC Power Electronics Systems Using Harmonic State Space (HSS) Method
DEFF Research Database (Denmark)
Kwon, Jun Bum; Wang, Xiongfei; Bak, Claus Leth
2015-01-01
based on the state-space averaging and generalized averaging, these also have limitations to show the same results as with the non-linear time domain simulations. This paper presents a modeling and simulation method for a large dc power electronic system by using Harmonic State Space (HSS) modeling....... Through this method, the required computation time and CPU memory for large dc power electronics systems can be reduced. Besides, the achieved results show the same results as with the non-linear time domain simulation, but with the faster simulation time which is beneficial in a large network....
Method to reduce arc blow during DC arc welding of pipelines
Energy Technology Data Exchange (ETDEWEB)
Espina-Hernandez, J. H.; Rueda-Morales, G.L.; Caleyo, F.; Hallen, J. M. [Instituto Politecnico Nacional, Mexico, (Mexico); Lopez-Montenegro, A.; Perz-Baruch, E. [Pemex Exploracion y Produccion, Tabasco, (Mexico)
2010-07-01
Steel pipelines are huge ferromagnetic structures and can be easily subjected to arc blow during the DC arc welding process. The development of methods to avoid arc blow during pipeline DC arc welding is a major objective in the pipeline industry. This study developed a simple procedure to compensate the residual magnetic field in the groove during DC arc welding. A Gaussmeter was used to perform magnetic flux density measurements in pipelines in southern Mexico. These data were used to perform magnetic finite element simulations using FEMM. Different variables were studied such as the residual magnetic field in the groove or the position of the coil with respect to the groove. An empirical predictive equation was developed from these trials to compensate for the residual magnetic field. A new method of compensating for the residual magnetic field in the groove by selecting the number of coil turns and the position of the coil with respect to the groove was established.
2011-06-01
... Model DC-10-10, DC- 10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F.... Applicability (c) This AD applies to all The Boeing Company Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10- 40, DC-10-40F, MD-10-10F, MD-10-30F, MD-11, and MD-11F airplanes...
Electromagnetic phenomena analysis in brushless DC motor with speed control using PWM method
Ciurys, Marek Pawel
2017-12-01
Field-circuit model of a brushless DC motor with speed control using PWM method was developed. Waveforms of electrical and mechanical quantities of the designed motor with a high pressure vane pump built in a rotor of the motor were computed. Analysis of electromagnetic phenomena in the system: single phase AC network - converter - BLDC motor was carried out.
Electromagnetic phenomena analysis in brushless DC motor with speed control using PWM method
Directory of Open Access Journals (Sweden)
Ciurys Marek Pawel
2017-12-01
Full Text Available Field-circuit model of a brushless DC motor with speed control using PWM method was developed. Waveforms of electrical and mechanical quantities of the designed motor with a high pressure vane pump built in a rotor of the motor were computed. Analysis of electromagnetic phenomena in the system: single phase AC network – converter - BLDC motor was carried out.
Analytical Method to Calculate the DC Link Current Stress in Voltage Source Converters
DEFF Research Database (Denmark)
Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Teodorescu, Remus
2014-01-01
for the applications with high line current ripple. The effect of the pulsewidth modulation (PWM) scheme on the rms value of the dc-link current is also studied and the analysis for continuous PWM and discontinuous PWM (DPWM) schemes is presented. The proposed analytical method is also verified experimentally....
Kumaravelu, Uma Devi; Mohamed Yakub, Sanavullah
2012-01-01
A method of simulation and modeling outer rotor permanent magnet brushless DC (ORPMBLDC) motor under dynamic conditions using finite element method by FEMM 4.2 software package is presented. In the proposed simulation, the torque developed at various positions of the rotor, under a complete cycle of excitation of the stator, is analysed. A novel method of sinusoidal excitation is proposed to enhance the overall torque development of ORPMBLDC motor.
Directory of Open Access Journals (Sweden)
Uma Devi Kumaravelu
2012-01-01
Full Text Available A method of simulation and modeling outer rotor permanent magnet brushless DC (ORPMBLDC motor under dynamic conditions using finite element method by FEMM 4.2 software package is presented. In the proposed simulation, the torque developed at various positions of the rotor, under a complete cycle of excitation of the stator, is analysed. A novel method of sinusoidal excitation is proposed to enhance the overall torque development of ORPMBLDC motor.
Krawczak, Ewelina; Gułkowski, Sławomir
2017-10-01
The use of aluminum contacts is common in the process of silicon solar cells production because of low contact resistivity. It has also a great importance in thin film technology for photovoltaics, especially in copper-indium-gallium-diselenide (CIGS) devices. The final stage of CIGS cell production is the top contact deposition of high conductivity layer for lateral current collection. Such material has to be highly optically transparent as well. In order to make a contact, metal is deposited onto TCO layer with minimum shadowing to allow as much light as possible into device. The metal grid contact is being made by deposition of few microns of aluminum. The resistivity of the deposited material as well as resistance between the metal grid and TCO layer plays a great role in high quality solar cell production. This paper presents the results of four point probe conductivity analysis of Al thin films deposited by direct current (DC) magnetron sputtering method. Influence of technological parameters of the Al deposition process on sheet resistance of deposited layers has been showed. In order to obtain the lowest resistivity of the thin contact layer, optimal set of sputtering parameters, i.e. power applied, deposition time and deposition pressure was found. The resistivity of the contact between two adjacent Al metal fingers deposited onto transparent conductive Al-doped zinc oxide film has been also examined.
Directory of Open Access Journals (Sweden)
Krawczak Ewelina
2017-01-01
Full Text Available The use of aluminum contacts is common in the process of silicon solar cells production because of low contact resistivity. It has also a great importance in thin film technology for photovoltaics, especially in copper-indium-gallium-diselenide (CIGS devices. The final stage of CIGS cell production is the top contact deposition of high conductivity layer for lateral current collection. Such material has to be highly optically transparent as well. In order to make a contact, metal is deposited onto TCO layer with minimum shadowing to allow as much light as possible into device. The metal grid contact is being made by deposition of few microns of aluminum. The resistivity of the deposited material as well as resistance between the metal grid and TCO layer plays a great role in high quality solar cell production. This paper presents the results of four point probe conductivity analysis of Al thin films deposited by direct current (DC magnetron sputtering method. Influence of technological parameters of the Al deposition process on sheet resistance of deposited layers has been showed. In order to obtain the lowest resistivity of the thin contact layer, optimal set of sputtering parameters, i.e. power applied, deposition time and deposition pressure was found. The resistivity of the contact between two adjacent Al metal fingers deposited onto transparent conductive Al-doped zinc oxide film has been also examined.
Applied mathematical methods in nuclear thermal hydraulics
International Nuclear Information System (INIS)
Ransom, V.H.; Trapp, J.A.
1983-01-01
Applied mathematical methods are used extensively in modeling of nuclear reactor thermal-hydraulic behavior. This application has required significant extension to the state-of-the-art. The problems encountered in modeling of two-phase fluid transients and the development of associated numerical solution methods are reviewed and quantified using results from a numerical study of an analogous linear system of differential equations. In particular, some possible approaches for formulating a well-posed numerical problem for an ill-posed differential model are investigated and discussed. The need for closer attention to numerical fidelity is indicated
Entropy viscosity method applied to Euler equations
International Nuclear Information System (INIS)
Delchini, M. O.; Ragusa, J. C.; Berry, R. A.
2013-01-01
The entropy viscosity method [4] has been successfully applied to hyperbolic systems of equations such as Burgers equation and Euler equations. The method consists in adding dissipative terms to the governing equations, where a viscosity coefficient modulates the amount of dissipation. The entropy viscosity method has been applied to the 1-D Euler equations with variable area using a continuous finite element discretization in the MOOSE framework and our results show that it has the ability to efficiently smooth out oscillations and accurately resolve shocks. Two equations of state are considered: Ideal Gas and Stiffened Gas Equations Of State. Results are provided for a second-order time implicit schemes (BDF2). Some typical Riemann problems are run with the entropy viscosity method to demonstrate some of its features. Then, a 1-D convergent-divergent nozzle is considered with open boundary conditions. The correct steady-state is reached for the liquid and gas phases with a time implicit scheme. The entropy viscosity method correctly behaves in every problem run. For each test problem, results are shown for both equations of state considered here. (authors)
Chaos analysis and chaotic EMI suppression of DC-DC converters
Zhang, Bo
2014-01-01
Introduces chaos theory, its analytical methods and the means to apply chaos to the switching power supply design DC-DC converters are typical switching systems which have plenty of nonlinear behaviors, such as bifurcation and chaos. The nonlinear behaviors of DC-DC converters have been studied heavily over the past 20 years, yet researchers are still unsure of the practical application of bifurcations and chaos in switching converters. The electromagnetic interference (EMI), which resulted from the high rates of changes of voltage and current, has become a major design criterion in DC-DC co
Method and apparatus for generating radiation utilizing DC to AC conversion with a conductive front
Dawson, J.M.; Mori, W.B.; Lai, C.H.; Katsouleas, T.C.
1998-07-14
Method and apparatus ar disclosed for generating radiation of high power, variable duration and broad tunability over several orders of magnitude from a laser-ionized gas-filled capacitor array. The method and apparatus convert a DC electric field pattern into a coherent electromagnetic wave train when a relativistic ionization front passes between the capacitor plates. The frequency and duration of the radiation is controlled by the gas pressure and capacitor spacing. 4 figs.
PENGGUNAAN FUZZY LOGIC UNTUK KONTROL PARALLEL CONVERTER DC-DC
Directory of Open Access Journals (Sweden)
Bambang Prio Hartono
2012-09-01
Full Text Available Abstract: Using system fuzzy logic as control technology have been used on low load dc-dc converter with combined parallel compiled dc-dc converter can obtain big load. With existence of differrence of component parameter and each parallel compiled converter can obtained different current and voltage output. Function of controller for to do adjustment, so that current which is applied to load by each converter can be obtained difference error as small as possible or same. The object of research is developing design of large signal dc-dc converter which is combined with using FLC so that obtain better performance. To get better performance have been made plant model and simulation with CDE method. The more systematic system and design is needed to overcome bigger load on dc-dc converter, so that parallel compiled current master slave control system on dc-dc converter with using fuzzy logic controller is used. Result of research showed that error or difference of current which is applied to load can handled by fuzzy logic controller. Technic of current and voltage controller co to do adjustment current and voltage distribution equally to load. Distribution of iL1,iL2 and output voltage Vo on dc-dc converter with load 2,25 until 7,875 and voltage 100 until 120 volt, load current beetwen 12 until 48, % relatif error Vo 0,4% until 0,9%.
Channel for Applied Investigations on Low Energy Ion Beams of Cyclotron DC-60
Gikal, B N; Borisenko, A N; Fateev, A A; Gulbekyan, G G; Kalagin, I V; Kazacha, V I; Kazarinov, N Yu; Kolesov, I V; Lebedev, N I; Lysukhin, S N; Melnikov, V N
2006-01-01
The channel intended for carrying out applied investigations on the low energy ion beams having the kinetic energy 25 $Z/A$ keV/a.u. and transported from the ECR-source to a target is worked out. The channel structure and parameters of all its optics elements are defined. The calculation results of different ion types transportation are given. It is shown that ions having the ratio of their mass to charge Z/A=2-20 can be transported in the worked out channel with enough high expected efficiency. At that the ion beam diameter on the target is $\\sim$40 mm. The characteristics of the basic optical elements of the channel are also given.
A Novel Method for Sensorless Speed Detection of Brushed DC Motors
Directory of Open Access Journals (Sweden)
Ernesto Vazquez-Sanchez
2016-12-01
Full Text Available Many motor applications require accurate speed measurement. For brushed dc motors, speed can be measured with conventional observers or sensorless observers. Sensorless observers have the advantage of not requiring any external devices to be attached to the motor. Instead, voltage and/or current are measured and used to estimate the speed. The sensorless observers are usually divided into two groups: those based on the dynamic model, and those based on the ripple component. This paper proposes a method that measures the current of brushed dc motors and analyses the position of its spectral components. From these spectral components, the method estimates the motor speed. Three tests, performed each with the speeds ranging from 2000 to 3000 rpm either at constant-speed, at slowly changing speeds, or at rapidly changing speeds, showed that the average error was below 1 rpm and that the deviation error was below 1.5 rpm. The proposed method: (i is a novel method that is not based on either the dynamic model or on the ripple component; (ii requires only the measurement of the current for the speed estimation; (iii can be used for brushed dc (direct current motors with a large number of coils; and (iv achieves a low error in the speed estimation.
Optimal design of a DC MHD pump by simulated annealing method
Directory of Open Access Journals (Sweden)
Bouali Khadidja
2014-01-01
Full Text Available In this paper a design methodology of a magnetohydrodynamic pump is proposed. The methodology is based on direct interpretation of the design problem as an optimization problem. The simulated annealing method is used for an optimal design of a DC MHD pump. The optimization procedure uses an objective function which can be the minimum of the mass. The constraints are both of geometrics and electromagnetic in type. The obtained results are reported.
Desalination of salt damaged Obernkirchen sandstone by an applied DC field
DEFF Research Database (Denmark)
Matyščák, Ondřej; Ottosen, Lisbeth M.; Rörig-Dalgaard, Inge
2014-01-01
Soluble salts are considered as one of the most common causes for decay of building materials. In the present work, an electrokinetic method for desalination of sandstones from a historic warehouse was tested. The sandstones claddings were removed from the warehouse during a renovation action...... as the outer surface was scaling due to salts.The focus of the work was on the effect of electrokinetic desalination for removal of unevenly distributed mixtures of salts. Previous reported studies were conducted with laboratory contaminated stones with single salts, which were relatively evenly distributed...... in the stones, i.e. the present investigation faces more challenges relevant to a real desalination action. Experiments were conducted with two Obernkirchen sandstones from the same warehouse, but with different levels of salt concentrations and porosity. The investigation includes removal of the most common...
Geostatistical methods applied to field model residuals
DEFF Research Database (Denmark)
Maule, Fox; Mosegaard, K.; Olsen, Nils
consists of measurement errors and unmodelled signal), and is typically assumed to be uncorrelated and Gaussian distributed. We have applied geostatistical methods to analyse the residuals of the Oersted(09d/04) field model [http://www.dsri.dk/Oersted/Field_models/IGRF_2005_candidates/], which is based......The geomagnetic field varies on a variety of time- and length scales, which are only rudimentary considered in most present field models. The part of the observed field that can not be explained by a given model, the model residuals, is often considered as an estimate of the data uncertainty (which...... on 5 years of Ørsted and CHAMP data, and includes secular variation and acceleration, as well as low-degree external (magnetospheric) and induced fields. The analysis is done in order to find the statistical behaviour of the space-time structure of the residuals, as a proxy for the data covariances...
Computational methods applied to wind tunnel optimization
Lindsay, David
methods, coordinate transformation theorems and techniques including the Method of Jacobians, and a derivation of the fluid flow fundamentals required for the model. It applies the methods to study the effect of cross-section and fillet variation, and to obtain a sample design of a high-uniformity nozzle.
International Nuclear Information System (INIS)
Rhodes, Scott; Perez, Juan; Elborai, Shihab; Lee, Se-Hee; Zahn, Markus
2005-01-01
New flows and instabilities are presented for a ferrofluid drop contained in glass Hele-Shaw cells with simultaneously applied in-plane clockwise rotating and DC axial uniform magnetic fields. When a ferrofluid drop is stressed by a uniform DC axial magnetic field, up to ∼250 G in 0.9-1.4 mm gap Hele-Shaw cells, the drop forms a labyrinth pattern. With subsequent application of an in-plane uniform rotating magnetic field, up to ∼100 G rms at frequency 20-40 Hz, smooth spirals form from viscous shear due to ferrofluid flow. If the rotating magnetic field is applied first, the drop is held together without a labyrinth. Gradual increase of the DC axial magnetic field, to a critical magnetic field value, results in an abrupt phase transformation from a large drop to many small discrete droplets. A preliminary minimum magnetization and surface energy analysis is presented to model the phase transformation
2010-11-05
... Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F... to supersede an existing airworthiness directive (AD) that applies to all Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F, MD-10- 10F, MD-10-30F, MD-11...
Linearized Modeling Methods of AC-DC Converters for an Accurate Frequency Response
DEFF Research Database (Denmark)
Kwon, Jun Bum; Wang, Xiongfei; Blaabjerg, Frede
2017-01-01
difficulties in modeling are discussed. A comparison of these methods is presented. Simulation results show that the harmonic state-space modeling method provides an efficient way to analyze both steady-state frequency coupling and dynamic harmonic interactions in power-electronic-based power systems.......Wideband harmonics and resonances are challenging the stability and power quality of emerging power-electronic-based power systems, and therefore, harmonic modeling and analysis of power converters are becoming even more important. However, the complex interactions on both ac and dc sides...
Directory of Open Access Journals (Sweden)
Chul-Sang Hwang
2016-12-01
Full Text Available This paper presents a decentralized control method for distributed generations (DGs in an islanded direct current (DC microgrid. In most typical DC microgrids, a decentralized control method is based on a voltage droop control method. However, the grid voltage differs from node to node due to line voltage drop, and hence the power sharing ratio among DGs cannot be matched with as desired value. Especially in an islanded DC microgrid including an energy storage system as a voltage source, it is difficult for DGs to maintain the charge state of the ESS in a decentralized way. To overcome this problem, state of charge (SOC-voltage droop control is applied to the ESS. By using the proposed droop method, the SOC information can be assigned to the grid voltage, and hence the other DGs are able to support the SOC in a decentralized way. For DGs to enhance the accuracy of the SOC estimation, voltage drop is compensated for based on forecasting data and line impedance data. The simulation is modeled and implemented using Power System Computer Aided Design/Electromagnetic Transients for DC (PSCAD/EMTDC, version 4.2, Winnipeg, Manitoba, Canada and the simulation results show that the capability to maintain SOC as well as the system voltage profile are improved by using the proposed method.
Energy Technology Data Exchange (ETDEWEB)
Borges, Eduardo M.; Braz Filho, Francisco A.; Guimaraes, Lamartine N.F. [Centro Tecnico Aeroespacial (CTA), Sao Jose dos Campos, SP (Brazil). Inst. de Estudos Avancados (IEAv)]. E-mail: Eduardo@ieav.cta.br; fbraz@ieav.cta.br; guimarae@ieav.cta.br
2005-07-01
Electromagnetic pumps use Faraday principle to liquid metal flow control, where DC electric current and magnetic field applied produce the Lorentz force on the liquid metal. In this paper the results of the computational simulation are compared to experimental data of Mercury DC electromagnetic pump operation and the BEMC-1 code is used to evaluation of DC electromagnetic pump performance applied to liquid metal flow control as Sodium, Lead and Bismuth, used in fast reactors. (author)
Generalized reciprocal method applied in processing seismic ...
African Journals Online (AJOL)
A geophysical investigation was carried out at Shika, near Zaria, using seismic refraction method; with the aim of analyzing the data obtained using the generalized reciprocal method (GRM). The technique is for delineating undulating refractors at any depth from in-line seismic refraction data consisting of forward and ...
Applying scrum methods to ITS projects.
2017-08-01
The introduction of new technology generally brings new challenges and new methods to help with deployments. Agile methodologies have been introduced in the information technology industry to potentially speed up development. The Federal Highway Admi...
Statistical classification methods applied to seismic discrimination
Energy Technology Data Exchange (ETDEWEB)
Ryan, F.M. [ed.; Anderson, D.N.; Anderson, K.K.; Hagedorn, D.N.; Higbee, K.T.; Miller, N.E.; Redgate, T.; Rohay, A.C.
1996-06-11
To verify compliance with a Comprehensive Test Ban Treaty (CTBT), low energy seismic activity must be detected and discriminated. Monitoring small-scale activity will require regional (within {approx}2000 km) monitoring capabilities. This report provides background information on various statistical classification methods and discusses the relevance of each method in the CTBT seismic discrimination setting. Criteria for classification method selection are explained and examples are given to illustrate several key issues. This report describes in more detail the issues and analyses that were initially outlined in a poster presentation at a recent American Geophysical Union (AGU) meeting. Section 2 of this report describes both the CTBT seismic discrimination setting and the general statistical classification approach to this setting. Seismic data examples illustrate the importance of synergistically using multivariate data as well as the difficulties due to missing observations. Classification method selection criteria are presented and discussed in Section 3. These criteria are grouped into the broad classes of simplicity, robustness, applicability, and performance. Section 4 follows with a description of several statistical classification methods: linear discriminant analysis, quadratic discriminant analysis, variably regularized discriminant analysis, flexible discriminant analysis, logistic discriminant analysis, K-th Nearest Neighbor discrimination, kernel discrimination, and classification and regression tree discrimination. The advantages and disadvantages of these methods are summarized in Section 5.
Applying Fuzzy Possibilistic Methods on Critical Objects
DEFF Research Database (Denmark)
Yazdani, Hossein; Ortiz-Arroyo, Daniel; Choros, Kazimierz
2016-01-01
Providing a ﬂexible environment to process data objects is a desirable goal of machine learning algorithms. In fuzzy and possibilistic methods, the relevance of data objects is evaluated and a membership degree is assigned. However, some critical objects objects have the potential ability to affect...... the performance of the clustering algorithms if they remain in a speciﬁc cluster or they are moved into another. In this paper we analyze and compare how critical objects affect the behaviour of fuzzy possibilistic methods in several data sets. The comparison is based on the accuracy and ability of learning...
Tutte's barycenter method applied to isotopies
de Verdiere, EC; Pocchiola, M; Vegter, G
This paper is concerned with applications of Tutte's barycentric embedding theorem (Proc. London Math. Soc. 13 (1963) 743-768). It presents a method for building isotopies of triangulations in the plane, based on Tutte's theorem and the computation of equilibrium stresses of graphs by
Spectral methods applied to Ising models
International Nuclear Information System (INIS)
DeFacio, B.; Hammer, C.L.; Shrauner, J.E.
1980-01-01
Several applications of Ising models are reviewed. A 2-d Ising model is studied, and the problem of describing an interface boundary in a 2-d Ising model is addressed. Spectral methods are used to formulate a soluble model for the surface tension of a many-Fermion system
Applying Human Computation Methods to Information Science
Harris, Christopher Glenn
2013-01-01
Human Computation methods such as crowdsourcing and games with a purpose (GWAP) have each recently drawn considerable attention for their ability to synergize the strengths of people and technology to accomplish tasks that are challenging for either to do well alone. Despite this increased attention, much of this transformation has been focused on…
[The diagnostic methods applied in mycology].
Kurnatowska, Alicja; Kurnatowski, Piotr
2008-01-01
The systemic fungal invasions are recognized with increasing frequency and constitute a primary cause of morbidity and mortality, especially in immunocompromised patients. Early diagnosis improves prognosis, but remains a problem because there is lack of sensitive tests to aid in the diagnosis of systemic mycoses on the one hand, and on the other the patients only present unspecific signs and symptoms, thus delaying early diagnosis. The diagnosis depends upon a combination of clinical observation and laboratory investigation. The successful laboratory diagnosis of fungal infection depends in major part on the collection of appropriate clinical specimens for investigations and on the selection of appropriate microbiological test procedures. So these problems (collection of specimens, direct techniques, staining methods, cultures on different media and non-culture-based methods) are presented in article.
Proteomics methods applied to malaria: Plasmodium falciparum
International Nuclear Information System (INIS)
Cuesta Astroz, Yesid; Segura Latorre, Cesar
2012-01-01
Malaria is a parasitic disease that has a high impact on public health in developing countries. The sequencing of the plasmodium falciparum genome and the development of proteomics have enabled a breakthrough in understanding the biology of the parasite. Proteomics have allowed to characterize qualitatively and quantitatively the parasite s expression of proteins and has provided information on protein expression under conditions of stress induced by antimalarial. Given the complexity of their life cycle, this takes place in the vertebrate host and mosquito vector. It has proven difficult to characterize the protein expression during each stage throughout the infection process in order to determine the proteome that mediates several metabolic, physiological and energetic processes. Two dimensional electrophoresis, liquid chromatography and mass spectrometry have been useful to assess the effects of antimalarial on parasite protein expression and to characterize the proteomic profile of different p. falciparum stages and organelles. The purpose of this review is to present state of the art tools and advances in proteomics applied to the study of malaria, and to present different experimental strategies used to study the parasite's proteome in order to show the advantages and disadvantages of each one.
Improved Design Methods for Robust Single- and Three-Phase ac-dc-ac Power Converters
DEFF Research Database (Denmark)
Qin, Zian
After a century of fast developing, the society is facing energy issues again, e.g. the exhaustion of fossil fuel, emission caused air pollution, radiation leakage of nuclear generation, and so on. How to produce and use electricity in a more sustainable, efficient, and cost-effective way thus...... becomes a emerging challenge. Accordingly, installation of sustainable power generators like wind turbines and solar panels has experienced a large increase during the last decades. Meanwhile, power electronics converters, as interfaces in electrical system, are delivering approximately 80 % electricity......, the emerging challenges, and the structure of the thesis. The main content of the thesis starts with single-phase converters: Chapter 2 and Chapter 3 propose new modulation methods for single-phase B6 and H6 converters, respectively, in order to retain the same dc link voltage with two full-bridges connected...
2.5-D and 3-D DC resistivity modelling using an extrapolation cascadic multigrid method
Pan, Kejia; Tang, Jingtian
2014-06-01
Multigrid methods are well known for their high efficiency in solving elliptic boundary value problems. In this study, an improved extrapolation cascadic multigrid (EXCMG) method is presented to solve large sparse systems of linear equations, which are discretized from both 2.5-D and 3-D DC resistivity modelling using the finite element methods. To increase the accuracy, the singularity generated by the source term is removed by reformulating the solution with the secondary potential. In addition, a set of new and efficient Fourier coefficient is presented to transform the solutions in the 2.5-D Fourier domain to the 3-D Cartesian domain. To show the efficiency and the ease-to-implement of EXCMG, we first implement the EXCMG methods to a two-layered model of both 2-D and 3-D and compare the results with the analytical solutions. It has been shown that the maximum relative error in apparent resistivity is no more than 0.4 per cent provided an appropriate grid size is chosen. Then the comparisons of EXCMG with two other iterative solvers [symmetric successive over-relaxation conjugate gradient (SSORCG) and incomplete Cholesky conjugate gradient (ICCG)] show that converging at a rate independent of the grid size, the EXCMG method is much more efficient than SSORCG and ICCG solvers. Moreover, the EXCMG method has been shown its potential for being generalized to large-scale 3-D problems, due to the fact that it becomes more efficient as the size of the problem increases.
Photovoltaic system with improved DC connections and method of making same
Cioffi, Philip Michael; Todorovic, Maja Harfman; Herzog, Michael Scott; Korman, Charles Steven; Doherty, Donald M.; Johnson, Neil Anthony
2017-06-20
A micro-inverter assembly includes a housing having an opening formed in a bottom surface thereof, and a direct current (DC)-to-alternating current (AC) micro-inverter disposed within the housing at a position adjacent to the opening. The micro-inverter assembly further includes a micro-inverter DC connector electrically coupled to the DC-to-AC micro-inverter and positioned within the opening of the housing, the micro-inverter DC connector having a plurality of exposed electrical contacts.
METHOD OF APPLYING NICKEL COATINGS ON URANIUM
Gray, A.G.
1959-07-14
A method is presented for protectively coating uranium which comprises etching the uranium in an aqueous etching solution containing chloride ions, electroplating a coating of nickel on the etched uranium and heating the nickel plated uranium by immersion thereof in a molten bath composed of a material selected from the group consisting of sodium chloride, potassium chloride, lithium chloride, and mixtures thereof, maintained at a temperature of between 700 and 800 deg C, for a time sufficient to alloy the nickel and uranium and form an integral protective coating of corrosion-resistant uranium-nickel alloy.
Versatile Formal Methods Applied to Quantum Information.
Energy Technology Data Exchange (ETDEWEB)
Witzel, Wayne [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Rudinger, Kenneth Michael [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sarovar, Mohan [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
2015-11-01
Using a novel formal methods approach, we have generated computer-veri ed proofs of major theorems pertinent to the quantum phase estimation algorithm. This was accomplished using our Prove-It software package in Python. While many formal methods tools are available, their practical utility is limited. Translating a problem of interest into these systems and working through the steps of a proof is an art form that requires much expertise. One must surrender to the preferences and restrictions of the tool regarding how mathematical notions are expressed and what deductions are allowed. Automation is a major driver that forces restrictions. Our focus, on the other hand, is to produce a tool that allows users the ability to con rm proofs that are essentially known already. This goal is valuable in itself. We demonstrate the viability of our approach that allows the user great exibility in expressing state- ments and composing derivations. There were no major obstacles in following a textbook proof of the quantum phase estimation algorithm. There were tedious details of algebraic manipulations that we needed to implement (and a few that we did not have time to enter into our system) and some basic components that we needed to rethink, but there were no serious roadblocks. In the process, we made a number of convenient additions to our Prove-It package that will make certain algebraic manipulations easier to perform in the future. In fact, our intent is for our system to build upon itself in this manner.
Digital peak current mode control with adaptive slope compensation for DC-DC converters
DEFF Research Database (Denmark)
Andersen, Karsten Holm; Nymand, Morten
2017-01-01
This paper presents an adaptive slope compensation method for peak current mode control of digital controlled DC-DC converters, which controls the quality factor of the complex conjugated poles at half the switching frequency. Using quality factor control enables optimization of the dynamic...... performance and stability of current mode control. The presented method adapt to DC-DC converter operating conditions by estimating the rising and falling inductor current slopes, to apply a current slope compensation value to obtain a constant quality factor. The experimental results verifies the theoretical...
A novel position-sensorless control method for brushless DC motors
International Nuclear Information System (INIS)
Zhang, X.Z.; Wang, Y.N.
2011-01-01
This paper presents the design and implementation of a high performance position-sensorless control scheme for the extensively used brushless DC (BLDC) motors. In the proposed method, with proper PWM strategy, instead of detecting the zero-crossing point (ZCP) of the nonexcited motor back electromagnetic force (EMF) or the average motor terminal to neutral voltage, the true zero-crossing points of back EMF are extracted directly from the difference of the specific average line-to-line voltages with simple RC circuits and comparators. In contrast to conventional methods, the neutral voltage is not needed and the diode freewheeling currents in the nonconducted phase are eliminated completely; therefore, the commutation signals are more accurate and insensitive to the common-mode noise. Moreover, 100% pulse-width-modulation (PWM) duty ratio control of BLDC motors is provided with the presented method. As a result, the proposed method makes it possible to achieve good motor performance over a wide speed range and to simplify the starting procedure. The detailed circuit model is analyzed and some experimental results obtained from a sensorless prototype are shown to verify the analysis and confirm the validity of the proposed method.
DEFF Research Database (Denmark)
Jin, Zheming; Meng, Lexuan; Guerrero, Josep M.
2017-01-01
DC distribution technology has become the new choice and the trending technology of shipboard power systems for its advancement over its AC counterpart. In DC shipboard power systems, the bus voltage stability is a critical issue. The presence of tightly controlled high-power constant power load ...
Thermal Modelling and Design of On-board DC-DC Power Converter using Finite Element Method
DEFF Research Database (Denmark)
Staliulionis, Z.; Zhang, Z.; Pittini, R.
2014-01-01
Power electronic converters are widely used and play a pivotal role in electronics area. The temperature causes around 54 % of all power converters failures. Thermal loads are nowadays one of the bottlenecks in the power system design and the cooling efficiency of a system is primarily determined...... the potential of such analysis was demonstrated by real-world measurements and comparison of obtained results. Thermal modelling was accomplished using finite element analysis software COMSOL and thermo-imaging camera was used to measure the thermal field distribution. Also, the improved configuration of power...... by numerical modelling techniques. Therefore, thermal design through thermal modelling and simulation is becoming an integral part of the design process as less expensive compared to the experimental cut-and-try approach. Here the investigation is performed using finite element method-based modelling, and also...
Thermal Modeling and Design of On-board DC-DC Power Converter using Finite Element Method
DEFF Research Database (Denmark)
Staliulionis, Zygimantas; Zhang, Zhe; Pittini, Riccardo
2014-01-01
Power electronic converters are widely used and play a pivotal role in electronics area . The temperature causes around 54 % of all power converters failures. Thermal loads are nowadays one of the bottlenecks in the power system design and the cooling efficiency of a system is primarily determined...... , and also the potential of such analysis was demonstrated by real - world measurements and comparison of obtained results . Thermal modeling was accomplishe d using finite element anal ysis software COMSOL and thermo - imaging camera was used to measure the thermal field distribution. Also, the improved...... by numerical modeling techniques. Therefore, thermal design through thermal modeling and simulation is becoming an integral part of the design process as less expensive compared to the experimenta l cut - and - try approach. Here the investigation is performed using finite element method - based modeling...
DEFF Research Database (Denmark)
Sakamuri, Jayachandra N.; Hansen, Anca Daniela; Altin, Müfit
2017-01-01
considering the operation of the WT at below rated wind speed. Moreover, the impact of release of overload on the dynamics of the wind turbine, therefore on the associated AC and DC grids are studied in this paper. Finally, the suitable overloading method is proposed based on the simulation and experimental...... results. The time domain simulations for fast primary frequency control are performed on an OWPP connected through a 3-terminal DC grid using DIgSILENT PowerFactory. The experiments are performed on OWPP model integrated to a laboratory scale 3-terminal DC grid test set up. Based on the simulations...... and experimental results, overloading method which considers the variation of WT output power during the overload provides better performance during and after release of the overload....
Reflections on Mixing Methods in Applied Linguistics Research
Hashemi, Mohammad R.
2012-01-01
This commentary advocates the use of mixed methods research--that is the integration of qualitative and quantitative methods in a single study--in applied linguistics. Based on preliminary findings from a research project in progress, some reflections on the current practice of mixing methods as a new trend in applied linguistics are put forward.…
DEFF Research Database (Denmark)
Wei, Baoze; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez
2017-01-01
This paper presents a theoretical study with experimental validation of a circulating-current suppression method for parallel operation of three-phase voltage source inverters (VSI), which may be suitable for modular parallel uninterruptible power supply systems or hybrid AC/DC microgrid...
International Nuclear Information System (INIS)
Lawler, J.S.
2001-01-01
The brushless dc motor (BDCM) has high-power density and efficiency relative to other motor types. These properties make the BDCM well suited for applications in electric vehicles provided a method can be developed for driving the motor over the 4 to 6:1 constant power speed range (CPSR) required by such applications. The present state of the art for constant power operation of the BDCM is conventional phase advance (CPA)[1]. In this paper, we identify key limitations of CPA. It is shown that the CPA has effective control over the developed power but that the current magnitude is relatively insensitive to power output and is inversely proportional to motor inductance. If the motor inductance is low, then the rms current at rated power and high speed may be several times larger than the current rating. The inductance required to maintain rms current within rating is derived analytically and is found to be large relative to that of BDCM designs using high-strength rare earth magnets. Th us, the CPA requires a BDCM with a large equivalent inductance
Design and development of DC high current sensor using Hall-Effect method
Dewi, Sasti Dwi Tungga; Panatarani, C.; Joni, I. Made
2016-02-01
This paper report a newly developed high DC current sensor by using a Hall effect method and also the measurement system. The Hall effect sensor receive the magnetic field generated by a current carrying conductor wire. The SS49E (Honeywell) magnetoresistive sensor was employed to sense the magnetic field from the field concentrator. The voltage received from SS49E then converted into digital by using analog to digital converter (ADC-10 bit). The digital data then processed in the microcontroller to be displayed as the value of the electric current in the LCD display. In addition the measurement was interfaced into Personal Computer (PC) using the communication protocols of RS232 which was finally displayed in real-time graphical form on the PC display. The performance test on the range ± 40 Ampere showed that the maximum relative error is 5.26%. It is concluded that the sensors and the measurement system worked properly according to the design with acceptable accuracy.
Luo, Fang Lin
2003-01-01
DC/DC conversion techniques have undergone rapid development in recent decades. With the pioneering work of these authors, DC/DC converters have now moved into their sixth generation. This book offers a concise, practical presentation of DC/DC converters, summarizing the spectrum of conversion tecnologies and presentingmany new ideas and more than 100 new topologies. Nowhere else in the literature are DC/DC converters so logically sorted and systematically introduced, and nowhere else can readers find detailed information on prototype topologies that represent a major contribution to modern power engineering. More than 320 figures, 60 tables, and 500 formulae facilitate understand and provide precise data.
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 introducing two band-pass filters (BPFs) into the output voltage and inductance current feedback of the ESC is proposed. Compared with the traditional dual-loop control method, the proposed method effectively reduces the SRC and improves the dynamic performance in case of a lower cut-off frequency...... in the outer voltage loop. Simultaneously, an adaptive droop control method by introducing the fine tuning virtual resistances is adopted to reduce the output voltage deviation of parallel ESCs and improve the output current sharing among the ESCs. Considering the allowed range of the deviation between...
Distributed AC power flow method for AC and AC-DC hybrid ...
African Journals Online (AJOL)
... on voltage level and R/X ratio in the formulation itself. DPFM is applied on a 10 bus, low voltage, microgrid system giving a better voltage profile.. Keywords: Microgrid (MG), Distributed Energy Resources (DER), Particle Swarm Optimization (OPF), Time varying inertia weight (TVIW), Distributed power flow method (DPFM) ...
DEFF Research Database (Denmark)
Lu, Xiaonan; Guerrero, Josep M.; Sun, Kai
2014-01-01
resistance in a droop-controlled dc microgrid, since the output voltage of each converter cannot be exactly the same, the output current sharing accuracy is degraded. Second, the DC bus voltage deviation increases with the load due to the droop action. In this paper, in order to improve the performance...... information between converter units. The droop controller is employed to achieve independent operation and average voltage and current controllers are used in each converter to simultaneously enhance the current sharing accuracy and restore the dc bus voltage. All of the controllers are realized locally...
Convergence of Iterative Methods applied to Boussinesq equation
Directory of Open Access Journals (Sweden)
Sh. S. Behzadi
2013-11-01
Full Text Available In this paper, a Boussinesq equation is solved by using the Adomian's decomposition method, modified Adomian's decomposition method, variational iteration method, modified variational iteration method, homotopy perturbation method, modified homotopy perturbation method and homotopy analysis method. The approximate solution of this equation is calculated in the form of series which its components are computed by applying a recursive relation. The existence and uniqueness of the solution and the convergence of the proposed methods are proved. A numerical example is studied to demonstrate the accuracy of the presented methods.
Discrimination symbol applying method for sintered nuclear fuel product
International Nuclear Information System (INIS)
Ishizaki, Jin
1998-01-01
The present invention provides a symbol applying method for applying discrimination information such as an enrichment degree on the end face of a sintered nuclear product. Namely, discrimination symbols of information of powders are applied by a sintering aid to the end face of a molded member formed by molding nuclear fuel powders under pressure. Then, the molded product is sintered. The sintering aid comprises aluminum oxide, a mixture of aluminum oxide and silicon dioxide, aluminum hydride or aluminum stearate alone or in admixture. As an applying means of the sintering aid, discrimination symbols of information of powders are drawn by an isostearic acid on the end face of the molded product, and the sintering aid is sprayed thereto, or the sintering aid is applied directly, or the sintering aid is suspended in isostearic acid, and the suspension is applied with a brush. As a result, visible discrimination information can be applied to the sintered member easily. (N.H.)
Method of applying a mirror reflecting layer to instrument parts
Alkhanov, L. G.; Danilova, I. A.; Delektorskiy, G. V.
1974-01-01
A method follows for applying a mirror reflecting layer to the surfaces of parts, instruments, apparatus, and so on. A brief analysis is presented of the existing methods of obtaining the mirror surface and the advantages of the new method of obtaining the mirror surface by polymer casting mold are indicated.
Directory of Open Access Journals (Sweden)
Wenzheng Xu
2017-10-01
Full Text Available Phase-shifted converters are practically important to provide high conversion efficiencies through soft-switching techniques. However, the limitation on a resonant inductor current in the converters often leads to a non-fulfillment of the requirement of minimum load current. This paper presents a new power electronics control technique to enable the dual features of bi-directional power flow and an extended load range for soft-switching in phase-shift-controlled DC-DC converters. The proposed technique utilizes two identical full bridge converters and inverters in conjunction with a new control logic for gate-driving signals to facilitate both Zero Current Switching (ZCS and Zero Voltage Switching (ZVS in a single phase-shift-controlled DC-DC converter. The additional ZCS is designed for light load conditions at which the minimum load current cannot be attained. The bi-directional phase-shift-controlled DC-DC converter can implement the function of synchronous rectification. Its fast dynamic response allows for quick energy recovery during the regenerative braking of traction systems in electrified trains.
Building "Applied Linguistic Historiography": Rationale, Scope, and Methods
Smith, Richard
2016-01-01
In this article I argue for the establishment of "Applied Linguistic Historiography" (ALH), that is, a new domain of enquiry within applied linguistics involving a rigorous, scholarly, and self-reflexive approach to historical research. Considering issues of rationale, scope, and methods in turn, I provide reasons why ALH is needed and…
DEFF Research Database (Denmark)
Lu, Xiaonan; Sun, Kai; Guerrero, Josep M.
2015-01-01
In this paper, a double-quadrant state-of-charge (SoC) based droop control method for distributed energy storage system (DESS) is proposed to reach the proper power distribution in autonomous DC microgrids. Since DESS is commonly used in DC microgrids, it is necessary to achieve the rational power...... sharing in both charging and discharging process. In order to prolong the lifetime of the energy storage units (ESUs) and avoid the overuse of a certain unit, the SoC of each unit should be balanced and the injected/output power should be gradually equalized. Droop control as a decentralized approach...... is used as the basis of the power sharing method for distributed energy storage units (DESUs). In the charging process, the droop coefficient is set to be proportional to the nth order of SoC, while in the discharging process, the droop coefficient is set to be inversely proportional to the nth order...
Sugai, I; Oyaizu, M; Kawakami, H; Hattori, Y; Kawasaki, K; Hayashizaki, N
2002-01-01
We have prepared very thin plastic supported carbon stripper foils (1.2+-0.3 mu g/cm sup 2) using a controlled DC arc-discharge (CDAD) method. The lifetime of these foils was measured with 3.2 MeV Ne sup + ions. These foils recorded lifetimes about four times longer at the maximum and three times longer on the average than those commercially available foils produced by evaporation-condensation.
Quantitative EEG Applying the Statistical Recognition Pattern Method
DEFF Research Database (Denmark)
Engedal, Knut; Snaedal, Jon; Hoegh, Peter
2015-01-01
BACKGROUND/AIM: The aim of this study was to examine the discriminatory power of quantitative EEG (qEEG) applying the statistical pattern recognition (SPR) method to separate Alzheimer's disease (AD) patients from elderly individuals without dementia and from other dementia patients. METHODS...
The harmonics detection method based on neural network applied ...
African Journals Online (AJOL)
The harmonics detection method based on neural network applied to harmonics compensation. R Dehini, A Bassou, B Ferdi. Abstract. Several different methods have been used to sense load currents and extract its harmonic component in order to produce a reference current in shunt active power filters (SAPF), and to ...
Qiu, Liming; Shen, Rongxi; Song, Dazhao; Wang, Enyuan; Liu, Zhentang; Niu, Yue; Jia, Haishan; Xia, Shankui; Zheng, Xiangxin
2017-12-01
An accurate and non-destructive evaluation method for the hydraulic measure impact range in coal seams is urgently needed. Aiming at the application demands, a theoretical study and field test are presented using the direct current (DC) method to evaluate the impact range of coal seam hydraulic measures. We firstly analyzed the law of the apparent resistivity response of an abnormal conductive zone in a coal seam, and then investigated the principle of non-destructive testing of the coal seam hydraulic measure impact range using the DC method, and used an accurate evaluation method based on the apparent resistivity cloud chart. Finally, taking hydraulic fracturing and hydraulic flushing as examples, field experiments were carried out in coal mines to evaluate the impact ranges. The results showed that: (1) in the process of hydraulic fracturing, coal conductivity was enhanced by high-pressure water in the coal seam, and after hydraulic fracturing, the boundary of the apparent resistivity decrease area was the boundary impact range. (2) In the process of hydraulic flushing, coal conductivity was reduced by holes and cracks in the coal seam, and after hydraulic flushing, the boundary of the apparent resistivity increase area was the boundary impact range. (3) After the implementation of the hydraulic measures, there may be some blind zones in the coal seam; in hydraulic fracturing blind zones, the apparent resistivity increased or stayed constant, while in hydraulic flushing blind zones, the apparent resistivity decreased or stayed constant. The DC method realized a comprehensive and non-destructive evaluation of the impact range of the hydraulic measures, and greatly reduced the time and cost of evaluation.
Hadri-Hamida, A.; Allag, A.; Hammoudi, M. Y.; Mimoune, S. M.; Zerouali, S.; Ayad, M. Y.; Becherif, M.; Miliani, E.; Miraoui, A.
2009-04-01
This paper presents a new control strategy for a three phase PWM converter, which consists of applying an adaptive nonlinear control. The input-output feedback linearization approach is based on the exact cancellation of the nonlinearity, for this reason, this technique is not efficient, because system parameters can vary. First a nonlinear system modelling is derived with state variables of the input current and the output voltage by using power balance of the input and output, the nonlinear adaptive backstepping control can compensate the nonlinearities in the nominal system and the uncertainties. Simulation results are obtained using Matlab/Simulink. These results show how the adaptive backstepping law updates the system parameters and provide an efficient control design both for tracking and regulation in order to improve the power factor.
Development of a New Method for Assembling a Bipolar DC Motor as a Teaching Material
Matsumoto, Yuki; Sakaki, Kei; Sakaki, Mamoru
2017-05-01
A simple handmade motor is a commonly used teaching aid for explaining the theory of the DC motor in science classes around the world. Kits that can be used by children to craft a simple motor are commercially available, and videos of assembling these motors are easily found on the internet. Although the design of this motor is simple, it is unipolar, meaning that the rotor consists of a single dipole. Thus, the Lorentz force acts only on one side of the coil per revolution. This decreases the energy conversion efficiency and requires the learners to turn the rotor using their hands in order to initiate rotation.
Applying the Taguchi method for optimized fabrication of bovine ...
African Journals Online (AJOL)
The objective of the present study was to optimize the fabrication of bovine serum albumin (BSA) nanoparticle by applying the Taguchi method with characterization of the nanoparticle bioproducts. BSA nanoparticles have been extensively studied in our previous works as suitable carrier for drug delivery, since they are ...
Linear algebraic methods applied to intensity modulated radiation therapy.
Crooks, S M; Xing, L
2001-10-01
Methods of linear algebra are applied to the choice of beam weights for intensity modulated radiation therapy (IMRT). It is shown that the physical interpretation of the beam weights, target homogeneity and ratios of deposited energy can be given in terms of matrix equations and quadratic forms. The methodology of fitting using linear algebra as applied to IMRT is examined. Results are compared with IMRT plans that had been prepared using a commercially available IMRT treatment planning system and previously delivered to cancer patients.
Machala, Z.; Jedlovský, I.; Chládeková, L.; Pongrác, B.; Giertl, D.; Janda, M.; Ikurová, L. Å.; Polčic, P.
2009-08-01
Three types of DC electrical discharges in atmospheric air (streamer corona, transient spark and glow discharge) were tested for bio-decontamination of bacteria and yeasts in water solution, and spores on surfaces. Static vs. flowing treatment of contaminated water were compared, in the latter the flowing water either covered the grounded electrode or passed through the high voltage needle electrode. The bacteria were killed most efficiently in the flowing regime by transient spark. Streamer corona was efficient when the treated medium flew through the active corona region. The spores on plastic foil and paper surfaces were successfully inactivated by negative corona. The microbes were handled and their population evaluated by standard microbiology cultivation procedures. The emission spectroscopy of the discharges and TBARS (thiobarbituric acid reactive substances) absorption spectrometric detection of the products of lipid peroxidation of bacterial cell membranes indicated a major role of radicals and reactive oxygen species among the bio-decontamination mechanisms.
Saito, Tatsuhito; Kondo, Keiichiro; Koseki, Takafumi
A DC-electrified railway system that is fed by diode rectifiers at a substation is unable to return the electric power to an AC grid. Accordingly, the braking cars have to restrict regenerative braking power when the power consumption of the powering cars is not sufficient. However, the characteristics of a DC-electrified railway system, including the powering cars, is not known, and a mathematical model for designing a controller has not been established yet. Hence, the object of this study is to obtain the mathematical model for an analytical design method of the regenerative braking control system. In the first part of this paper, the static characteristics of this system are presented to show the position of the equilibrium point. The linearization of this system at the equilibrium point is then performed to describe the dynamic characteristics of the system. An analytical design method is then proposed on the basis of these characteristics. The proposed design method is verified by experimental tests with a 1kW class miniature model, and numerical simulations.
Pedersen, F.
2008-09-01
The presented bidirectional DC/DC converter design concept is a further development of an already existing converter used for low battery voltage operation.For low battery voltage operation a high efficient low parts count DC/DC converter was developed, and used in a satellite for the battery charge and battery discharge function.The converter consists in a bidirectional, non regulating DC/DC converter connected to a discharge regulating Buck converter and a charge regulating Buck converter.The Bidirectional non regulating DC/DC converter performs with relatively high efficiency even at relatively high currents, which here means up to 35Amps.This performance was obtained through the use of power MOSFET's with on- resistances of only a few mille Ohms connected to a special transformer allowing paralleling several transistor stages on the low voltage side of the transformer. The design is patent protected. Synchronous rectification leads to high efficiency at the low battery voltages considered, which was in the range 2,7- 4,3 Volt DC.The converter performs with low switching losses as zero voltage zero current switching is implemented in all switching positions of the converter.Now, the drive power needed, to switch a relatively large number of low Ohm , hence high drive capacitance, power MOSFET's using conventional drive techniques would limit the overall conversion efficiency.Therefore a resonant drive consuming considerable less power than a conventional drive circuit was implemented in the converter.To the originally built and patent protected bidirectional non regulating DC/DC converter, is added the functionality of regulation.Hereby the need for additional converter stages in form of a Charge Buck regulator and a Discharge Buck regulator is eliminated.The bidirectional DC/DC converter can be used in connection with batteries, motors, etc, where the bidirectional feature, simple design and high performance may be useful.
Methods of applied mathematics with a software overview
Davis, Jon H
2016-01-01
This textbook, now in its second edition, provides students with a firm grasp of the fundamental notions and techniques of applied mathematics as well as the software skills to implement them. The text emphasizes the computational aspects of problem solving as well as the limitations and implicit assumptions inherent in the formal methods. Readers are also given a sense of the wide variety of problems in which the presented techniques are useful. Broadly organized around the theme of applied Fourier analysis, the treatment covers classical applications in partial differential equations and boundary value problems, and a substantial number of topics associated with Laplace, Fourier, and discrete transform theories. Some advanced topics are explored in the final chapters such as short-time Fourier analysis and geometrically based transforms applicable to boundary value problems. The topics covered are useful in a variety of applied fields such as continuum mechanics, mathematical physics, control theory, and si...
Using VPython to Apply Mathematics to Physics in Mathematical Methods
Demaree, Dedra; Eagan, J.; Finn, P.; Knight, B.; Singleton, J.; Therrien, A.
2006-12-01
At the College of the Holy Cross, the sophomore mathematical methods of physics students completed VPython programming projects. This is the first time VPython has been used in a physics course at this college. These projects were aimed at applying some methods learned to actual physical situations. Students first completed worksheets from North Carolina State University to learn the programming environment. They then used VPython to apply the mathematics of vectors and differential equations learned in class to solve physics situations which appear simple but are not easy to solve analytically. For most of these students it was their first programming experience. It was also one of the only chances we had to do actual physics applications during the semester due to the large amount of mathematical content covered. In addition to showcasing the students’ final programs, this poster will share their view of including VPython in this course.
Synthetic data. A proposed method for applied risk management
Carbajal De Nova, Carolina
2017-01-01
The proposed method attempts to contribute towards the econometric and simulation applied risk management literature. It consists on an algorithm to construct synthetic data and risk simulation econometric models, supported by a set of behavioral assumptions. This algorithm has the advantage of replicating natural phenomena and uncertainty events in a short period of time. These features convey economically low costs besides computational efficiency. An application for wheat farmers is develo...
Newton-Krylov methods applied to nonequilibrium radiation diffusion
International Nuclear Information System (INIS)
Knoll, D.A.; Rider, W.J.; Olsen, G.L.
1998-01-01
The authors present results of applying a matrix-free Newton-Krylov method to a nonequilibrium radiation diffusion problem. Here, there is no use of operator splitting, and Newton's method is used to convert the nonlinearities within a time step. Since the nonlinear residual is formed, it is used to monitor convergence. It is demonstrated that a simple Picard-based linearization produces a sufficient preconditioning matrix for the Krylov method, thus elevating the need to form or store a Jacobian matrix for Newton's method. They discuss the possibility that the Newton-Krylov approach may allow larger time steps, without loss of accuracy, as compared to an operator split approach where nonlinearities are not converged within a time step
Methods for model selection in applied science and engineering.
Energy Technology Data Exchange (ETDEWEB)
Field, Richard V., Jr.
2004-10-01
Mathematical models are developed and used to study the properties of complex systems and/or modify these systems to satisfy some performance requirements in just about every area of applied science and engineering. A particular reason for developing a model, e.g., performance assessment or design, is referred to as the model use. Our objective is the development of a methodology for selecting a model that is sufficiently accurate for an intended use. Information on the system being modeled is, in general, incomplete, so that there may be two or more models consistent with the available information. The collection of these models is called the class of candidate models. Methods are developed for selecting the optimal member from a class of candidate models for the system. The optimal model depends on the available information, the selected class of candidate models, and the model use. Classical methods for model selection, including the method of maximum likelihood and Bayesian methods, as well as a method employing a decision-theoretic approach, are formulated to select the optimal model for numerous applications. There is no requirement that the candidate models be random. Classical methods for model selection ignore model use and require data to be available. Examples are used to show that these methods can be unreliable when data is limited. The decision-theoretic approach to model selection does not have these limitations, and model use is included through an appropriate utility function. This is especially important when modeling high risk systems, where the consequences of using an inappropriate model for the system can be disastrous. The decision-theoretic method for model selection is developed and applied for a series of complex and diverse applications. These include the selection of the: (1) optimal order of the polynomial chaos approximation for non-Gaussian random variables and stationary stochastic processes, (2) optimal pressure load model to be
Dynarski, Mark; Betts, Julian; Feldman, Jill
2016-01-01
The DC Opportunity Scholarship Program (OSP), established in 2004, is the only federally-funded private school voucher program for low-income parents in the United States. This evaluation brief describes findings using data from more than 2,000 applicants' parents, who applied to the program from spring 2011 to spring 2013 following…
Analysis of concrete beams using applied element method
Lincy Christy, D.; Madhavan Pillai, T. M.; Nagarajan, Praveen
2018-03-01
The Applied Element Method (AEM) is a displacement based method of structural analysis. Some of its features are similar to that of Finite Element Method (FEM). In AEM, the structure is analysed by dividing it into several elements similar to FEM. But, in AEM, elements are connected by springs instead of nodes as in the case of FEM. In this paper, background to AEM is discussed and necessary equations are derived. For illustrating the application of AEM, it has been used to analyse plain concrete beam of fixed support condition. The analysis is limited to the analysis of 2-dimensional structures. It was found that the number of springs has no much influence on the results. AEM could predict deflection and reactions with reasonable degree of accuracy.
Applying sample survey methods to clinical trials data.
LaVange, L M; Koch, G G; Schwartz, T A
This paper outlines the utility of statistical methods for sample surveys in analysing clinical trials data. Sample survey statisticians face a variety of complex data analysis issues deriving from the use of multi-stage probability sampling from finite populations. One such issue is that of clustering of observations at the various stages of sampling. Survey data analysis approaches developed to accommodate clustering in the sample design have more general application to clinical studies in which repeated measures structures are encountered. Situations where these methods are of interest include multi-visit studies where responses are observed at two or more time points for each patient, multi-period cross-over studies, and epidemiological studies for repeated occurrences of adverse events or illnesses. We describe statistical procedures for fitting multiple regression models to sample survey data that are more effective for repeated measures studies with complicated data structures than the more traditional approaches of multivariate repeated measures analysis. In this setting, one can specify a primary sampling unit within which repeated measures have intraclass correlation. This intraclass correlation is taken into account by sample survey regression methods through robust estimates of the standard errors of the regression coefficients. Regression estimates are obtained from model fitting estimation equations which ignore the correlation structure of the data (that is, computing procedures which assume that all observational units are independent or are from simple random samples). The analytic approach is straightforward to apply with logistic models for dichotomous data, proportional odds models for ordinal data, and linear models for continuously scaled data, and results are interpretable in terms of population average parameters. Through the features summarized here, the sample survey regression methods have many similarities to the broader family of
DEFF Research Database (Denmark)
Lu, Xiaonan; Sun, Kai; Guerrero, Josep M.
2014-01-01
In this paper, a droop control based state-of-charge (SoC) balancing method in autonomous DC microgrids is proposed. Both charging and discharging process have been considered. In particular, in the charging process, the droop coefficient is set to be proportional to SoCn, and in the discharging...... in the discharging process. Meanwhile, the ESU with lower SoC absorbs more power in the charging process and delivers less power in the discharging process. Eventually, the SoC and injected/output power in each ESU are equalized. The exponent n for SoC is employed to regulate the balancing speed of the So......C and injected/output power. It is demonstrated that with higher exponent n, the balancing speed is higher. Simulation model comprised of three ESUs is implemented by using MATLAB/Simulink. The proposed method is verified by the simulation results....
Mclyman, C. W.
1983-01-01
Compact dc/dc inverter uses single integrated-circuit package containing six inverter gates that generate and amplify 100-kHz square-wave switching signal. Square-wave switching inverts 10-volt local power to isolated voltage at another desired level. Relatively high operating frequency reduces size of filter capacitors required, resulting in small package unit.
Early Oscillation Detection for DC/DC Converter Fault Diagnosis
Wang, Bright L.
2011-01-01
The electrical power system of a spacecraft plays a very critical role for space mission success. Such a modern power system may contain numerous hybrid DC/DC converters both inside the power system electronics (PSE) units and onboard most of the flight electronics modules. One of the faulty conditions for DC/DC converter that poses serious threats to mission safety is the random occurrence of oscillation related to inherent instability characteristics of the DC/DC converters and design deficiency of the power systems. To ensure the highest reliability of the power system, oscillations in any form shall be promptly detected during part level testing, system integration tests, flight health monitoring, and on-board fault diagnosis. The popular gain/phase margin analysis method is capable of predicting stability levels of DC/DC converters, but it is limited only to verification of designs and to part-level testing on some of the models. This method has to inject noise signals into the control loop circuitry as required, thus, interrupts the DC/DC converter's normal operation and increases risks of degrading and damaging the flight unit. A novel technique to detect oscillations at early stage for flight hybrid DC/DC converters was developed.
Classification of Specialized Farms Applying Multivariate Statistical Methods
Directory of Open Access Journals (Sweden)
Zuzana Hloušková
2017-01-01
Full Text Available Classification of specialized farms applying multivariate statistical methods The paper is aimed at application of advanced multivariate statistical methods when classifying cattle breeding farming enterprises by their economic size. Advantage of the model is its ability to use a few selected indicators compared to the complex methodology of current classification model that requires knowledge of detailed structure of the herd turnover and structure of cultivated crops. Output of the paper is intended to be applied within farm structure research focused on future development of Czech agriculture. As data source, the farming enterprises database for 2014 has been used, from the FADN CZ system. The predictive model proposed exploits knowledge of actual size classes of the farms tested. Outcomes of the linear discriminatory analysis multifactor classification method have supported the chance of filing farming enterprises in the group of Small farms (98 % filed correctly, and the Large and Very Large enterprises (100 % filed correctly. The Medium Size farms have been correctly filed at 58.11 % only. Partial shortages of the process presented have been found when discriminating Medium and Small farms.
Enhanced Molecular Dynamics Methods Applied to Drug Design Projects.
Ziada, Sonia; Braka, Abdennour; Diharce, Julien; Aci-Sèche, Samia; Bonnet, Pascal
2018-01-01
Nobel Laureate Richard P. Feynman stated: "[…] everything that living things do can be understood in terms of jiggling and wiggling of atoms […]." The importance of computer simulations of macromolecules, which use classical mechanics principles to describe atom behavior, is widely acknowledged and nowadays, they are applied in many fields such as material sciences and drug discovery. With the increase of computing power, molecular dynamics simulations can be applied to understand biological mechanisms at realistic timescales. In this chapter, we share our computational experience providing a global view of two of the widely used enhanced molecular dynamics methods to study protein structure and dynamics through the description of their characteristics, limits and we provide some examples of their applications in drug design. We also discuss the appropriate choice of software and hardware. In a detailed practical procedure, we describe how to set up, run, and analyze two main molecular dynamics methods, the umbrella sampling (US) and the accelerated molecular dynamics (aMD) methods.
Metrological evaluation of characterization methods applied to nuclear fuels
International Nuclear Information System (INIS)
Faeda, Kelly Cristina Martins; Lameiras, Fernando Soares; Camarano, Denise das Merces; Ferreira, Ricardo Alberto Neto; Migliorini, Fabricio Lima; Carneiro, Luciana Capanema Silva; Silva, Egonn Hendrigo Carvalho
2010-01-01
In manufacturing the nuclear fuel, characterizations are performed in order to assure the minimization of harmful effects. The uranium dioxide is the most used substance as nuclear reactor fuel because of many advantages, such as: high stability even when it is in contact with water at high temperatures, high fusion point, and high capacity to retain fission products. Several methods are used for characterization of nuclear fuels, such as thermogravimetric analysis for the ratio O / U, penetration-immersion method, helium pycnometer and mercury porosimetry for the density and porosity, BET method for the specific surface, chemical analyses for relevant impurities, and the laser flash method for thermophysical properties. Specific tools are needed to control the diameter and the sphericity of the microspheres and the properties of the coating layers (thickness, density, and degree of anisotropy). Other methods can also give information, such as scanning and transmission electron microscopy, X-ray diffraction, microanalysis, and mass spectroscopy of secondary ions for chemical analysis. The accuracy of measurement and level of uncertainty of the resulting data are important. This work describes a general metrological characterization of some techniques applied to the characterization of nuclear fuel. Sources of measurement uncertainty were analyzed. The purpose is to summarize selected properties of UO 2 that have been studied by CDTN in a program of fuel development for Pressurized Water Reactors (PWR). The selected properties are crucial for thermalhydraulic codes to study basic design accidents. The thermal characterization (thermal diffusivity and thermal conductivity) and the penetration immersion method (density and open porosity) of UO 2 samples were focused. The thermal characterization of UO 2 samples was determined by the laser flash method between room temperature and 448 K. The adaptive Monte Carlo Method was used to obtain the endpoints of the
Nuclear and nuclear related analytical methods applied in environmental research
International Nuclear Information System (INIS)
Popescu, Ion V.; Gheboianu, Anca; Bancuta, Iulian; Cimpoca, G. V; Stihi, Claudia; Radulescu, Cristiana; Oros Calin; Frontasyeva, Marina; Petre, Marian; Dulama, Ioana; Vlaicu, G.
2010-01-01
Nuclear Analytical Methods can be used for research activities on environmental studies like water quality assessment, pesticide residues, global climatic change (transboundary), pollution and remediation. Heavy metal pollution is a problem associated with areas of intensive industrial activity. In this work the moss bio monitoring technique was employed to study the atmospheric deposition in Dambovita County Romania. Also, there were used complementary nuclear and atomic analytical methods: Neutron Activation Analysis (NAA), Atomic Absorption Spectrometry (AAS) and Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). These high sensitivity analysis methods were used to determine the chemical composition of some samples of mosses placed in different areas with different pollution industrial sources. The concentrations of Cr, Fe, Mn, Ni and Zn were determined. The concentration of Fe from the same samples was determined using all these methods and we obtained a very good agreement, in statistical limits, which demonstrate the capability of these analytical methods to be applied on a large spectrum of environmental samples with the same results. (authors)
Analysis of Brick Masonry Wall using Applied Element Method
Lincy Christy, D.; Madhavan Pillai, T. M.; Nagarajan, Praveen
2018-03-01
The Applied Element Method (AEM) is a versatile tool for structural analysis. Analysis is done by discretising the structure as in the case of Finite Element Method (FEM). In AEM, elements are connected by a set of normal and shear springs instead of nodes. AEM is extensively used for the analysis of brittle materials. Brick masonry wall can be effectively analyzed in the frame of AEM. The composite nature of masonry wall can be easily modelled using springs. The brick springs and mortar springs are assumed to be connected in series. The brick masonry wall is analyzed and failure load is determined for different loading cases. The results were used to find the best aspect ratio of brick to strengthen brick masonry wall.
Applied systems ecology: models, data, and statistical methods
Energy Technology Data Exchange (ETDEWEB)
Eberhardt, L L
1976-01-01
In this report, systems ecology is largely equated to mathematical or computer simulation modelling. The need for models in ecology stems from the necessity to have an integrative device for the diversity of ecological data, much of which is observational, rather than experimental, as well as from the present lack of a theoretical structure for ecology. Different objectives in applied studies require specialized methods. The best predictive devices may be regression equations, often non-linear in form, extracted from much more detailed models. A variety of statistical aspects of modelling, including sampling, are discussed. Several aspects of population dynamics and food-chain kinetics are described, and it is suggested that the two presently separated approaches should be combined into a single theoretical framework. It is concluded that future efforts in systems ecology should emphasize actual data and statistical methods, as well as modelling.
Energy Technology Data Exchange (ETDEWEB)
Naveen, C. S., E-mail: jayanna60@gmail.com; Jayanna, H. S., E-mail: jayanna60@gmail.com; Lamani, Ashok R., E-mail: jayanna60@gmail.com; Rajeeva, M. P., E-mail: jayanna60@gmail.com [Department of PG Studies and Research in Physics, Kuvempu University, Shankaraghatta- 577451, Shimoga, Karnataka (India)
2014-04-24
ZnO nanoparticles of different size were prepared by varying the molar ratio of glycine and zinc nitrate hexahydrate as fuel and oxidizer (F/O = 0.8, 1.11, 1.7) by simple solution combustion method. Powder samples were characterized by UV-Visible spectrophotometer, X-ray diffractometer, Scanning electron microscope (SEM). DC electrical conductivity measurements at room temperature and in the temperature range of 313-673K were carried out for the prepared thick films and it was found to increase with increase of temperature which confirms the semiconducting nature of the samples. Activation energies were calculated and it was found that, F/O molar ratio 1.7 has low E{sub AL} (Low temperature activation energy) and high E{sub AH} (High temperature activation energy) compared to other samples.
Deceuster, John; Etienne, Adélaïde; Robert, Tanguy; Nguyen, Frédéric; Kaufmann, Olivier
2014-04-01
Several techniques are available to estimate the depth of investigation or to identify possible artifacts in dc resistivity surveys. Commonly, the depth of investigation (DOI) is mainly estimated by using an arbitrarily chosen cut-off value on a selected indicator (resolution, sensitivity or DOI index). Ranges of cut-off values are recommended in the literature for the different indicators. However, small changes in threshold values may induce strong variations in the estimated depths of investigation. To overcome this problem, we developed a new statistical method to estimate the DOI of dc resistivity surveys based on a modified DOI index approach. This method is composed of 5 successive steps. First, two inversions are performed by using different resistivity reference models for the inversion (0.1 and 10 times the arithmetic mean of the logarithm of the observed apparent resistivity values). Inversion models are extended to the edges of the survey line and to a depth range of three times the pseudodepth of investigation of the largest array spacing used. In step 2, we compute the histogram of a newly defined scaled DOI index. Step 3 consists of the fitting of the mixture of two Gaussian distributions (G1 and G2) to the cumulative distribution function of the scaled DOI index values. Based on this fitting, step 4 focuses on the computation of an interpretation index (II) defined for every cell j of the model as the relative probability density that the cell j belongs to G1, which describes the Gaussian distribution of the cells with a scaled DOI index close to 0.0. In step 5, a new inversion is performed by using a third resistivity reference model (the arithmetic mean of the logarithm of the observed apparent resistivity values). The final electrical resistivity image is produced by using II as alpha blending values allowing the visual discrimination between well-constrained areas and poorly-constrained cells.
DC Rocks! Using Place-Based Learning to Introduce Washington DC's K-12 Students to the Geosciences
Mayberry, G. C.; Mattietti, G. K.
2017-12-01
The Washington DC area has interesting geology and a multitude of agencies that deal with the geosciences, yet K-12 public school students in DC, most of whom are minorities, have limited exposure to the geosciences. Geoscience agencies in the DC area have a unique opportunity to address this by introducing the geosciences to local students who otherwise may not have such an opportunity, by highlighting the geology in the students' "backyard," and by leveraging partnerships among DC-based geoscience-related agencies. The USGS and George Mason University are developing a project called DC Rocks, which will give DC's students an exciting introduction into the world of geoscience with place-based learning opportunities that will make geoscience relevant to their lives and their futures. Both the need in DC and the potential for lasting impact are great; the geosciences have the lowest racial diversity of all the science, technology, engineering, and math (STEM) fields, 89% of students in DC public schools are minorities, and there is no dedicated geoscience curriculum in DC. DC Rocks aims to give these students early exposure to the earth sciences, and encourage them to consider careers in the profession. DC Rocks will work with partner agencies to apply several methods that are recommended by researchers to increase the participation of minority students in the geosciences, including providing profoundly positive experiences that spark interest in the geosciences (Levine et al., 2007); increasing students' sense of belonging in the geosciences (Huntoon, et al, 2016); and place-based teaching practices that emphasize the study of local sites (Semken, 2005), such as DC's Rock Creek Park. DC Rocks will apply these methods by coordinating local geoscientists and resources to provide real-world examples of the geosciences' impact on students' lives. Through the DC Rocks website, educators will be able to request geoscience-related resources such as class presentations by
Analytical methods applied to diverse types of Brazilian propolis
Directory of Open Access Journals (Sweden)
Marcucci Maria
2011-06-01
Full Text Available Abstract Propolis is a bee product, composed mainly of plant resins and beeswax, therefore its chemical composition varies due to the geographic and plant origins of these resins, as well as the species of bee. Brazil is an important supplier of propolis on the world market and, although green colored propolis from the southeast is the most known and studied, several other types of propolis from Apis mellifera and native stingless bees (also called cerumen can be found. Propolis is usually consumed as an extract, so the type of solvent and extractive procedures employed further affect its composition. Methods used for the extraction; analysis the percentage of resins, wax and insoluble material in crude propolis; determination of phenolic, flavonoid, amino acid and heavy metal contents are reviewed herein. Different chromatographic methods applied to the separation, identification and quantification of Brazilian propolis components and their relative strengths are discussed; as well as direct insertion mass spectrometry fingerprinting. Propolis has been used as a popular remedy for several centuries for a wide array of ailments. Its antimicrobial properties, present in propolis from different origins, have been extensively studied. But, more recently, anti-parasitic, anti-viral/immune stimulating, healing, anti-tumor, anti-inflammatory, antioxidant and analgesic activities of diverse types of Brazilian propolis have been evaluated. The most common methods employed and overviews of their relative results are presented.
2D Stabilised analytic signal method in DC pole-pole potential data ...
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22
Using analytic signal method, interpretation of pole-pole secondary electric potentials due to 2D conductive/resistive prisms is presented. The estimated parameters are the location, lateral extent or width and depth to top surface of the prism. Forward modelling is attempted by 2D-Finite. Difference method. The proposed ...
Method of applying a coating onto a steel plate
International Nuclear Information System (INIS)
Masuda, Hiromasa; Murakami, Shozo; Chihara, Yoshihi.
1970-01-01
A method of applying a protective coating onto a steel plate to protect it from corrosion is given, using an irradiation process and a vehicle consisting of a radically polymerizable high molecular compound, a radically polymerizable less-volatile monomer and/or a functional intermediate agent, and a volatile solvent. The radiation may be electron beams at an energy level ranging from 100 to 1,000 keV. An advantage of this invention is that the ratio of the prepolymer to the monomer can be kept constant without difficulty during the irradiation operation, so that the variation in thickness is very small. Another advantage is that the addition of a monomer is not necessary for viscosity reduction, so that the optimum cross-linking density can be obtained. The molecular weight is so high that application by spraying is possible. The solvent remaining after the irradiation operation has substantially no influence on the polymerization hardening and gel content. In one example, 62 parts of prepolymer produced by reacting an epoxy resin Epikote No.1001 with an equal equivalent of acrylic acid were mixed with 17 parts of hydroxyl ethyl acrylate, 77.5 parts of methyl ethyl ketone and 5.5 parts of isopropyl alcohol to produce a vehicle composition. This composition was applied onto the surface of glass plate 20 microns in thickness. The monomer remaining in the mixture showed a very small change over an elapsed period of time. (Iwakiri, K.)
On interval methods applied to robot reliability quantification
International Nuclear Information System (INIS)
Carreras, C.; Walker, I.D.
2000-01-01
Interval methods have recently been successfully applied to obtain significantly improved robot reliability estimates via fault trees for the case of uncertain and time-varying input reliability data. These initial studies generated output distributions of failure probabilities by extending standard interval arithmetic with new abstractions called interval grids which can be parameterized to control the complexity and accuracy of the estimation process. In this paper different parameterization strategies are evaluated in order to gain a more complete understanding of the potential benefits of the approach. A canonical example of a robot manipulator system is used to show that an appropriate selection of parameters is a key issue for the successful application of such novel interval-based methodologies
Parallel fast multipole boundary element method applied to computational homogenization
Ptaszny, Jacek
2018-01-01
In the present work, a fast multipole boundary element method (FMBEM) and a parallel computer code for 3D elasticity problem is developed and applied to the computational homogenization of a solid containing spherical voids. The system of equation is solved by using the GMRES iterative solver. The boundary of the body is dicretized by using the quadrilateral serendipity elements with an adaptive numerical integration. Operations related to a single GMRES iteration, performed by traversing the corresponding tree structure upwards and downwards, are parallelized by using the OpenMP standard. The assignment of tasks to threads is based on the assumption that the tree nodes at which the moment transformations are initialized can be partitioned into disjoint sets of equal or approximately equal size and assigned to the threads. The achieved speedup as a function of number of threads is examined.
The virtual fields method applied to spalling tests on concrete
Directory of Open Access Journals (Sweden)
Forquin P.
2012-08-01
Full Text Available For one decade spalling techniques based on the use of a metallic Hopkinson bar put in contact with a concrete sample have been widely employed to characterize the dynamic tensile strength of concrete at strain-rates ranging from a few tens to two hundreds of s−1. However, the processing method mainly based on the use of the velocity profile measured on the rear free surface of the sample (Novikov formula remains quite basic and an identification of the whole softening behaviour of the concrete is out of reach. In the present paper a new processing method is proposed based on the use of the Virtual Fields Method (VFM. First, a digital high speed camera is used to record the pictures of a grid glued on the specimen. Next, full-field measurements are used to obtain the axial displacement field at the surface of the specimen. Finally, a specific virtual field has been defined in the VFM equation to use the acceleration map as an alternative ‘load cell’. This method applied to three spalling tests allowed to identify Young’s modulus during the test. It was shown that this modulus is constant during the initial compressive part of the test and decreases in the tensile part when micro-damage exists. It was also shown that in such a simple inertial test, it was possible to reconstruct average axial stress profiles using only the acceleration data. Then, it was possible to construct local stress-strain curves and derive a tensile strength value.
Potassium fertilizer applied by different methods in the zucchini crop
Directory of Open Access Journals (Sweden)
Carlos N. V. Fernandes
Full Text Available ABSTRACT Aiming to evaluate the effect of potassium (K doses applied by the conventional method and fertigation in zucchini (Cucurbita pepo L., a field experiment was conducted in Fortaleza, CE, Brazil. The statistical design was a randomized block, with four replicates, in a 4 x 2 factorial scheme, which corresponded to four doses of K (0, 75, 150 and 300 kg K2O ha-1 and two fertilization methods (conventional and fertigation. The analyzed variables were: fruit mass (FM, number of fruits (NF, fruit length (FL, fruit diameter (FD, pulp thickness (PT, soluble solids (SS, yield (Y, water use efficiency (WUE and potassium use efficiency (KUE, besides an economic analysis using the net present value (NPV, internal rate of return (IRR and payback period (PP. K doses influenced FM, FD, PT and Y, which increased linearly, with the highest value estimated at 36,828 kg ha-1 for the highest K dose (300 kg K2O ha-1. This dose was also responsible for the largest WUE, 92 kg ha-1 mm-1. KUE showed quadratic behavior and the dose of 174 kg K2O ha-1 led to its maximum value (87.41 kg ha-1 (kg K2O ha-1-1. All treatments were economically viable, and the most profitable months were May, April, December and November.
a Novel Method for Improving Plasma Nitriding Efficiency: Pre-Magnetization by DC Magnetic Field
Kovaci, Halim; Yetim, Ali Fatih; Bozkurt, Yusuf Burak; Çelik, Ayhan
2017-06-01
In this study, a novel pre-magnetization process, which enables easy diffusion of nitrogen, was used to enhance plasma nitriding efficiency. Firstly, magnetic fields with intensities of 1500G and 2500G were applied to the untreated samples before nitriding. After the pre-magnetization, the untreated and pre-magnetized samples were plasma nitrided for 4h in a gas mixture of 50% N2-50% H2 at 500∘C and 600∘C. The structural, mechanical and morphological properties of samples were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), microhardness tester and surface tension meter. It was observed that pre-magnetization increased the surface energy of the samples. Therefore, both compound and diffusion layer thicknesses increased with pre-magnetization process before nitriding treatment. As modified layer thickness increased, higher surface hardness values were obtained.
2D Stabilised analytic signal method in DC pole-pole potential data ...
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22
Using analytic signal method, interpretation of pole-pole secondary electric potentials due to 2D conductive/resistive prisms is presented. ... residual separation to separate out residual anom- alies, which are interpreted for geological .... terms, which are used for the semi-quantitative interpretation. 6.1 Computation of ...
A Generic Topology Derivation Method for Single-phase Converters with Active Capacitive DC-links
DEFF Research Database (Denmark)
Wang, Haoran; Wang, Huai; Zhu, Guorong
2016-01-01
capacitive DCDC- link solutions, but important aspects of the topology assess-ment, such as the total energy storage, overall capacitive energy buffer ratio, cost, and reliability are still not available. This paper proposes a generic topology derivation method of single-phase power converters...
Distributed AC power flow method for AC and AC-DC hybrid ...
African Journals Online (AJOL)
DR OKE
Keywords: Microgrid (MG), Distributed Energy Resources (DER), Particle Swarm Optimization (OPF), Time varying inertia weight (TVIW), Distributed power flow method (DPFM). DOI: http://dx.doi.org/10.4314/ijest.v7i3.8S. 1. Introduction. Small scale fossil fuel based generation systems, renewable energy based sources, ...
Flood Hazard Mapping by Applying Fuzzy TOPSIS Method
Han, K. Y.; Lee, J. Y.; Keum, H.; Kim, B. J.; Kim, T. H.
2017-12-01
There are lots of technical methods to integrate various factors for flood hazard mapping. The purpose of this study is to suggest the methodology of integrated flood hazard mapping using MCDM(Multi Criteria Decision Making). MCDM problems involve a set of alternatives that are evaluated on the basis of conflicting and incommensurate criteria. In this study, to apply MCDM to assessing flood risk, maximum flood depth, maximum velocity, and maximum travel time are considered as criterion, and each applied elements are considered as alternatives. The scheme to find the efficient alternative closest to a ideal value is appropriate way to assess flood risk of a lot of element units(alternatives) based on various flood indices. Therefore, TOPSIS which is most commonly used MCDM scheme is adopted to create flood hazard map. The indices for flood hazard mapping(maximum flood depth, maximum velocity, and maximum travel time) have uncertainty concerning simulation results due to various values according to flood scenario and topographical condition. These kind of ambiguity of indices can cause uncertainty of flood hazard map. To consider ambiguity and uncertainty of criterion, fuzzy logic is introduced which is able to handle ambiguous expression. In this paper, we made Flood Hazard Map according to levee breach overflow using the Fuzzy TOPSIS Technique. We confirmed the areas where the highest grade of hazard was recorded through the drawn-up integrated flood hazard map, and then produced flood hazard map can be compared them with those indicated in the existing flood risk maps. Also, we expect that if we can apply the flood hazard map methodology suggested in this paper even to manufacturing the current flood risk maps, we will be able to make a new flood hazard map to even consider the priorities for hazard areas, including more varied and important information than ever before. Keywords : Flood hazard map; levee break analysis; 2D analysis; MCDM; Fuzzy TOPSIS
Globally Convergent Homotopy Methods for the DC Operating PointProblem
Melville, Robert C.; Trajkovic, Ljiljana; Fang, San-Chin; Watson, Layne T.
1990-01-01
Accurate and efficient computer simulation of a proposed design for an integrated circuit ("chip") is essential because of the difficulty and expense of building prototypes for such devices. The transistors and diodes in such circuits are modeled with nonlinear equations, hence simulation of circuits requires the solution of systems of nonlinear equations involving hundreds or even thousands of variables. This paper discusses the application of probability-one homotopy methods to various sy...
DC resistivity of Ni-Zn ferrites prepared by oxalate precipitation method
International Nuclear Information System (INIS)
Shinde, T.J.; Gadkari, A.B.; Vasambekar, P.N.
2008-01-01
Polycrystalline ferrites with general formula Ni 1-x Zn x Fe 2 O 4 (x = 0, 0.2, 0.4, 0.6, 0.8, and 1.0) were prepared by oxalate precipitation method. The samples were characterized by X-ray diffraction (XRD), IR and scanning electron microscope (SEM) techniques. All compositions show cubic Spinel structure. Lattice constant increases with increase in zinc content, obeying Vegard's law. The physical densities are about 98.14% of their X-ray density. Average crystallite size lies in the range 27.59-31.49 nm. Infrared studies show two absorption bands near about 400 cm -1 and 600 cm -1 for octahedral and tetrahedral sites, respectively. The resistivity of all the samples was studied. It is observed that the resistivity of nickel-zinc ferrites prepared by oxalate precipitation method is higher than that prepared by ceramic and citrate precursor method. It is attributed to greater homogeneity and smaller grain size. Activation energy in paramagnetic region is higher than that of ferrimagnetic region
DEFF Research Database (Denmark)
Wu, Weimin; Qin, Weibo; Wang, Houqin
2017-01-01
the “Buck” mode, the control-to-grid current transfer function of this dual “Buck-Boost” AC/DC converter has a movable zero, which is related to the input power and the output DC voltage. When the input power increases, the movable zero will slide to the lower frequency range. And then, the gain between...... the cut-off frequency point and the resonant frequency of LCL filter will swell up, resulting in reduced amplitude margin and suppressed bandwidth of system. Based on the theoretical analysis, a new dynamic pole placement compensation control design method is proposed for this dual AC/DC converter......Recently, an LCL-filter-based dual “Buck-Boost” AC/DC converter for DC Nano-grid with three terminal outputs was proposed. Since it is a high order filter based single-phase converter, a RC damper is adopted to keep the system stable. This converter has two work modes: “Boost” and “Buck”. During...
Genualdi, Susie; MacMahon, Shaun; Robbins, Katherine; Farris, Samantha; Shyong, Nicole; DeJager, Lowri
2016-01-01
Sudan I, II, III and IV dyes are banned for use as food colorants in the United States and European Union because they are toxic and carcinogenic. These dyes have been illegally used as food additives in products such as chilli spices and palm oil to enhance their red colour. From 2003 to 2005, the European Union made a series of decisions requiring chilli spices and palm oil imported to the European Union to contain analytical reports declaring them free of Sudan I-IV. In order for the USFDA to investigate the adulteration of palm oil and chilli spices with unapproved colour additives in the United States, a method was developed for the extraction and analysis of Sudan dyes in palm oil, and previous methods were validated for Sudan dyes in chilli spices. Both LC-DAD and LC-MS/MS methods were examined for their limitations and effectiveness in identifying adulterated samples. Method validation was performed for both chilli spices and palm oil by spiking samples known to be free of Sudan dyes at concentrations close to the limit of detection. Reproducibility, matrix effects, and selectivity of the method were also investigated. Additionally, for the first time a survey of palm oil and chilli spices was performed in the United States, specifically in the Washington, DC, area. Illegal dyes, primarily Sudan IV, were detected in palm oil at concentrations from 150 to 24 000 ng ml(-1). Low concentrations (< 21 µg kg(-1)) of Sudan dyes were found in 11 out of 57 spices and are most likely a result of cross-contamination during preparation and storage and not intentional adulteration.
Preparation of copper doped DLC films by DC PE-CVD method
International Nuclear Information System (INIS)
Marton, M.; Vojs, M.; Kotlar, M.; Michniak, P.; Flickyngerova, S.; Vesely, M.; Redhammer, R.
2012-01-01
We used PECVD method for deposition of Cu incorporated DLC thin films from CH 4 /Ar gas mixture. The size of nanoparticles varied with changing the deposition conditions in the range of tenth to hundreds of nm. After annealing process, new small Cu particles appeared in the space between the as deposited ones, and all the particles were distributed more homogenous within the films. The resistivity of the DLC films decreased first with adding of copper to 10 to 6·10 3 Ωcm, and second with the annealing process to 4·10 -2 to 3 Ωcm. Raman spectra show the tendency of DLCs to become more graphitic with increasing annealing temperature, which may be one possible contribution to increased conductivity of the annealed Cu-DLC films. (authors)
Applying multi-resolution numerical methods to geodynamics
Davies, David Rhodri
Computational models yield inaccurate results if the underlying numerical grid fails to provide the necessary resolution to capture a simulation's important features. For the large-scale problems regularly encountered in geodynamics, inadequate grid resolution is a major concern. The majority of models involve multi-scale dynamics, being characterized by fine-scale upwelling and downwelling activity in a more passive, large-scale background flow. Such configurations, when coupled to the complex geometries involved, present a serious challenge for computational methods. Current techniques are unable to resolve localized features and, hence, such models cannot be solved efficiently. This thesis demonstrates, through a series of papers and closely-coupled appendices, how multi-resolution finite-element methods from the forefront of computational engineering can provide a means to address these issues. The problems examined achieve multi-resolution through one of two methods. In two-dimensions (2-D), automatic, unstructured mesh refinement procedures are utilized. Such methods improve the solution quality of convection dominated problems by adapting the grid automatically around regions of high solution gradient, yielding enhanced resolution of the associated flow features. Thermal and thermo-chemical validation tests illustrate that the technique is robust and highly successful, improving solution accuracy whilst increasing computational efficiency. These points are reinforced when the technique is applied to geophysical simulations of mid-ocean ridge and subduction zone magmatism. To date, successful goal-orientated/error-guided grid adaptation techniques have not been utilized within the field of geodynamics. The work included herein is therefore the first geodynamical application of such methods. In view of the existing three-dimensional (3-D) spherical mantle dynamics codes, which are built upon a quasi-uniform discretization of the sphere and closely coupled
Analytic methods in applied probability in memory of Fridrikh Karpelevich
Suhov, Yu M
2002-01-01
This volume is dedicated to F. I. Karpelevich, an outstanding Russian mathematician who made important contributions to applied probability theory. The book contains original papers focusing on several areas of applied probability and its uses in modern industrial processes, telecommunications, computing, mathematical economics, and finance. It opens with a review of Karpelevich's contributions to applied probability theory and includes a bibliography of his works. Other articles discuss queueing network theory, in particular, in heavy traffic approximation (fluid models). The book is suitable
Geophysical modeling in gold deposit through DC Resistivity and Induced Polarization methods
Directory of Open Access Journals (Sweden)
César Augusto Moreira
Full Text Available Abstract Ore mining fundamentally depends on the definition of its tenor and volume, something extremely complex in disseminated mineralization, as in the case of certain types of deposits of gold and sulfites. This article proposes the use of electrical tomography for definition of a geophysical signature in terms of electrical resistivity and chargeability, in an outcrop of mineralized quartz lode at the end of an inactive gold mine. One of the targets was to analyze the continuity of the mineralized body, the occurrence of new outcrops and the applicability of the method as an auxiliary tool in mineral extraction. Three parallel lines of electrical tomography in a dipole-dipole arrangement, being orthogonal to the orientation of the gold lode, were installed in an area outside the mine. The results allowed the geophysical characterization of the mineralized zone by high resistivity (above 1000Ω.m and high chargeability (above 30mV/V. The results of the 2D inversion models were interpolated in 3D visualization models, which allowed definition of the contour surfaces for the physical parameters measured, and the morphological pattern modeling of the mineralization. The data reveal the existence of a new lode in subsurface, localized 30m to the south of the lode outcrop. The versatility of the acquisition and data processing indicate the application potential of electrical tomography as a criterion for sampling and tenor definition in ore extraction activities, since it is objective and low cost.
Economic Droop Scheme for Decentralized Power Management in DC Microgrids
Directory of Open Access Journals (Sweden)
E. Alizadeh
2016-12-01
Full Text Available This paper proposes an autonomous and economic droop control scheme for DC microgrid application. In this method, a cost-effective power sharing technique among various types of DG units is properly adopted. The droop settings are determined based on an algorithm to individually manage the power management without any complicated optimization methods commonly applied in the centralized control method. In the proposed scheme, the system retains all the advantages of the traditional droop method while minimizes the generation costs of the DC microgrid. In the proposed method, all DGs are classified in a sorting rule based on their total generation cost and the reference voltage of their droop equations is then determined. The proposed scheme is applied to a typical DC microgrid consisting of four different types of DGs and a controllable load. The simulation results are presented to verify the effectiveness of the proposed method using MATLAB/SIMULINK software.
Review on finite element method | Erhunmwun | Journal of Applied ...
African Journals Online (AJOL)
Journal of Applied Sciences and Environmental Management. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 21, No 5 (2017) >. Log in or Register to get access to full text downloads.
Acti-Glide: a simple method of applying compression hosiery.
Hampton, Sylvie
2005-05-01
Compression hosiery is often worn to help prevent aching legs and swollen ankles, to prevent ulceration, to treat venous ulceration or to treat varicose veins. However, patients and nurses may experience problems applying hosiery and this can lead to non-concordance in patients and possibly reluctance from nurses to use compression hosiery. A simple solution to applying firm hosiery is Acti-Glide from Activa Healthcare.
Mesoscopic electronics beyond DC transport
di Carlo, Leonardo
Since the inception of mesoscopic electronics in the 1980's, direct current (dc) measurements have underpinned experiments in quantum transport. Novel techniques complementing dc transport are becoming paramount to new developments in mesoscopic electronics, particularly as the road is paved toward quantum information processing. This thesis describes seven experiments on GaAs/AlGaAs and graphene nanostructures unified by experimental techniques going beyond traditional dc transport. Firstly, dc current induced by microwave radiation applied to an open chaotic quantum dot is investigated. Asymmetry of mesoscopic fluctuations of induced current in perpendicular magnetic field is established as a tool for separating the quantum photovoltaic effect from classical rectification. A differential charge sensing technique is next developed using integrated quantum point contacts to resolve the spatial distribution of charge inside a double quantum clot. An accurate method for determining interdot tunnel coupling and electron temperature using charge sensing is demonstrated. A two-channel system for detecting current noise in mesoscopic conductors is developed, enabling four experiments where shot noise probes transmission properties not available in dc transport and Johnson noise serves as an electron thermometer. Suppressed shot noise is observed in quantum point contacts at zero parallel magnetic field, associated with the 0.7 structure in conductance. This suppression evolves with increasing field into the shot-noise signature of spin-lifted mode degeneracy. Quantitative agreement is found with a phenomenological model for density-dependent mode splitting. Shot noise measurements of multi-lead quantum-dot structures in the Coulomb blockade regime distill the mechanisms by which Coulomb interaction and quantum indistinguishability correlate electron flow. Gate-controlled sign reversal of noise cross correlation in two capacitively-coupled dots is observed, and shown to
Dose rate reduction method for NMCA applied BWR plants
International Nuclear Information System (INIS)
Nagase, Makoto; Aizawa, Motohiro; Ito, Tsuyoshi; Hosokawa, Hideyuki; Varela, Juan; Caine, Thomas
2012-09-01
BRAC (BWR Radiation Assessment and Control) dose rate is used as an indicator of the incorporation of activated corrosion by products into BWR recirculation piping, which is known to be a significant contributor to dose rate received by workers during refueling outages. In order to reduce radiation exposure of the workers during the outage, it is desirable to keep BRAC dose rates as low as possible. After HWC was adopted to reduce IGSCC, a BRAC dose rate increase was observed in many plants. As a countermeasure to these rapid dose rate increases under HWC conditions, Zn injection was widely adopted in United States and Europe resulting in a reduction of BRAC dose rates. However, BRAC dose rates in several plants remain high, prompting the industry to continue to investigate methods to achieve further reductions. In recent years a large portion of the BWR fleet has adopted NMCA (NobleChem TM ) to enhance the hydrogen injection effect to suppress SCC. After NMCA, especially OLNC (On-Line NobleChem TM ), BRAC dose rates were observed to decrease. In some OLNC applied BWR plants this reduction was observed year after year to reach a new reduced equilibrium level. This dose rate reduction trends suggest the potential dose reduction might be obtained by the combination of Pt and Zn injection. So, laboratory experiments and in-plant tests were carried out to evaluate the effect of Pt and Zn on Co-60 deposition behaviour. Firstly, laboratory experiments were conducted to study the effect of noble metal deposition on Co deposition on stainless steel surfaces. Polished type 316 stainless steel coupons were prepared and some of them were OLNC treated in the test loop before the Co deposition test. Water chemistry conditions to simulate HWC were as follows: Dissolved oxygen, hydrogen and hydrogen peroxide were below 5 ppb, 100 ppb and 0 ppb (no addition), respectively. Zn was injected to target a concentration of 5 ppb. The test was conducted up to 1500 hours at 553 K. Test
A Feedback Passivation Design for DC Microgrid and Its DC/DC Converters
Directory of Open Access Journals (Sweden)
Feifan Ji
2016-12-01
Full Text Available There are difficulties in analyzing the stability of microgrids since they are located on various network structures. However, considering that the network often consists of passive elements, the passivity theory is applied in this paper to solve the above-mentioned problem. It has been formerly shown that when the network is weakly strictly positive real (WSPR, the DC microgrid is stable if all interfaces between the microgrid and converters are made to be passive, which is called interface passivity. Then, the feedback passivation method is proposed for the controller design of various DC–DC converters to achieve the interface passivity. The interface passivity is different from the passivity of closed-loop systems on which the passivity based control (PBC concentrates. The feedback passivation design is detailed for typical buck converters and boost converters in terms of conditions that the controller parameters should satisfy. The theoretical results are verified by a hardware-in-loop real-time labotray (RTLab simulation of a DC microgrid with four generators.
Applied Research of Decision Tree Method on Football Training
Directory of Open Access Journals (Sweden)
Liu Jinhui
2015-01-01
Full Text Available This paper will make an analysis of decision tree at first, and then offer a further analysis of CLS based on it. As CLS contains the most substantial and most primitive decision-making idea, it can provide the basis of decision tree establishment. Due to certain limitation in details, the ID3 decision tree algorithm is introduced to offer more details. It applies information gain as attribute selection metrics to provide reference for seeking the optimal segmentation point. At last, the ID3 algorithm is applied in football training. Verification is made on this algorithm and it has been proved effectively and reasonably.
Muon radiography method for fundamental and applied research
Alexandrov, A. B.; Vladymyrov, M. S.; Galkin, V. I.; Goncharova, L. A.; Grachev, V. M.; Vasina, S. G.; Konovalova, N. S.; Malovichko, A. A.; Managadze, A. K.; Okat'eva, N. M.; Polukhina, N. G.; Roganova, T. M.; Starkov, N. I.; Tioukov, V. E.; Chernyavsky, M. M.; Shchedrina, T. V.
2017-12-01
This paper focuses on the basic principles of the muon radiography method, reviews the major muon radiography experiments, and presents the first results in Russia obtained by the authors using this method based on emulsion track detectors.
Cao, Jia; Yan, Zheng; He, Guangyu
2016-06-01
This paper introduces an efficient algorithm, multi-objective human learning optimization method (MOHLO), to solve AC/DC multi-objective optimal power flow problem (MOPF). Firstly, the model of AC/DC MOPF including wind farms is constructed, where includes three objective functions, operating cost, power loss, and pollutant emission. Combining the non-dominated sorting technique and the crowding distance index, the MOHLO method can be derived, which involves individual learning operator, social learning operator, random exploration learning operator and adaptive strategies. Both the proposed MOHLO method and non-dominated sorting genetic algorithm II (NSGAII) are tested on an improved IEEE 30-bus AC/DC hybrid system. Simulation results show that MOHLO method has excellent search efficiency and the powerful ability of searching optimal. Above all, MOHLO method can obtain more complete pareto front than that by NSGAII method. However, how to choose the optimal solution from pareto front depends mainly on the decision makers who stand from the economic point of view or from the energy saving and emission reduction point of view.
Power flow analysis for DC voltage droop controlled DC microgrids
DEFF Research Database (Denmark)
Li, Chendan; Chaudhary, Sanjay; Dragicevic, Tomislav
2014-01-01
This paper proposes a new algorithm for power flow analysis in droop controlled DC microgrids. By considering the droop control in the power flow analysis for the DC microgrid, when compared with traditional methods, more accurate analysis results can be obtained. The algorithm verification...
Urabe, Keiichiro; Shirai, Naoki; Tomita, Kentaro; Akiyama, Tsuyoshi; Murakami, Tomoyuki
2016-08-01
The density and temperature of electrons and key heavy particles were measured in an atmospheric-pressure pulsed-dc helium discharge plasma with a nitrogen molecular impurity generated using system with a liquid or metal anode and a metal cathode. To obtain these parameters, we conducted experiments using several laser-aided methods: Thomson scattering spectroscopy to obtain the spatial profiles of electron density and temperature, Raman scattering spectroscopy to obtain the neutral molecular nitrogen rotational temperature, phase-modulated dispersion interferometry to determine the temporal variation of the electron density, and time-resolved laser absorption spectroscopy to analyze the temporal variation of the helium metastable atom density. The electron density and temperature measured by Thomson scattering varied from 2.4 × 1014 cm-3 and 1.8 eV at the center of the discharge to 0.8 × 1014 cm-3 and 1.5 eV near the outer edge of the plasma in the case of the metal anode, respectively. The electron density obtained with the liquid anode was approximately 20% smaller than that obtained with the metal anode, while the electron temperature was not significantly affected by the anode material. The molecular nitrogen rotational temperatures were 1200 K with the metal anode and 1650 K with the liquid anode at the outer edge of the plasma column. The density of helium metastable atoms decreased by a factor of two when using the liquid anode.
New Method for Tuning Robust Controllers Applied to Robot Manipulators
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Gerardo Romero
2012-11-01
Full Text Available This paper presents a methodology to select the parameters of a nonlinear controller using Linear Matrix Inequalities (LMI. The controller is applied to a robotic manipulator to improve its robustness. This type of dynamic system enables the robust control law to be applied because it largely depends on the mathematical model of the system; however, in most cases it is impossible to be completely precise. The discrepancy between the dynamic behaviour of the robot and its mathematical model is taken into account by including a nonlinear term that represents the model's uncertainty. The controller's parameters are selected with two purposes: to guarantee the asymptotic stability of the closed-loop system while taking into account the uncertainty, and to increase its robustness margin. The results are validated with numerical simulations for a particular case study; these are then compared with previously published results to prove a better controller performance.
Waste classification and methods applied to specific disposal sites
International Nuclear Information System (INIS)
Rogers, V.C.
1979-01-01
An adequate definition of the classes of radioactive wastes is necessary to regulating the disposal of radioactive wastes. A classification system is proposed in which wastes are classified according to characteristics relating to their disposal. Several specific sites are analyzed with the methodology in order to gain insights into the classification of radioactive wastes. Also presented is the analysis of ocean dumping as it applies to waste classification. 5 refs
Radiation-Tolerant DC-DC Converters
Skutt, Glenn; Sable, Dan; Leslie, Leonard; Graham, Shawn
2012-01-01
A document discusses power converters suitable for space use that meet the DSCC MIL-PRF-38534 Appendix G radiation hardness level P classification. A method for qualifying commercially produced electronic parts for DC-DC converters per the Defense Supply Center Columbus (DSCC) radiation hardened assurance requirements was developed. Development and compliance testing of standard hybrid converters suitable for space use were completed for missions with total dose radiation requirements of up to 30 kRad. This innovation provides the same overall performance as standard hybrid converters, but includes assurance of radiation- tolerant design through components and design compliance testing. This availability of design-certified radiation-tolerant converters can significantly reduce total cost and delivery time for power converters for space applications that fit the appropriate DSCC classification (30 kRad).
Review on finite element method | Erhunmwun | Journal of Applied ...
African Journals Online (AJOL)
... finite elements, so that it is possible to systematically construct the approximation functions needed in a variational or weighted-residual approximation of the solution of a problem over each element. Keywords: Weak Formulation, Discretisation, Numerical methods, Finite element method, Global equations, Nodal solution ...
The flow curvature method applied to canard explosion
Energy Technology Data Exchange (ETDEWEB)
Ginoux, Jean-Marc [Laboratoire Protee, IUT de Toulon, Universite du Sud, BP 20132, F-83957 La Garde cedex (France); Llibre, Jaume, E-mail: ginoux@univ-tln.fr, E-mail: jllibre@mat.uab.cat [Departament de Matematiques, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain)
2011-11-18
The aim of this work is to establish that the bifurcation parameter value leading to a canard explosion in dimension 2 obtained by the so-called geometric singular perturbation method can be found according to the flow curvature method. This result will be then exemplified with the classical Van der Pol oscillator. (paper)
The flow curvature method applied to canard explosion
Ginoux, Jean-Marc; Llibre, Jaume
2011-11-01
The aim of this work is to establish that the bifurcation parameter value leading to a canard explosion in dimension 2 obtained by the so-called geometric singular perturbation method can be found according to the flow curvature method. This result will be then exemplified with the classical Van der Pol oscillator.
Literature Review of Applying Visual Method to Understand Mathematics
Directory of Open Access Journals (Sweden)
Yu Xiaojuan
2015-01-01
Full Text Available As a new method to understand mathematics, visualization offers a new way of understanding mathematical principles and phenomena via image thinking and geometric explanation. It aims to deepen the understanding of the nature of concepts or phenomena and enhance the cognitive ability of learners. This paper collates and summarizes the application of this visual method in the understanding of mathematics. It also makes a literature review of the existing research, especially with a visual demonstration of Euler’s formula, introduces the application of this method in solving relevant mathematical problems, and points out the differences and similarities between the visualization method and the numerical-graphic combination method, as well as matters needing attention for its application.
Methodical Aspects of Applying Strategy Map in an Organization
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Piotr Markiewicz
2013-06-01
Full Text Available One of important aspects of strategic management is the instrumental aspect included in a rich set of methods and techniques used at particular stages of strategic management process. The object of interest in this study is the development of views and the implementation of strategy as an element of strategic management and instruments in the form of methods and techniques. The commonly used method in strategy implementation and measuring progress is Balanced Scorecard (BSC. The method was created as a result of implementing the project “Measuring performance in the Organization of the future” of 1990, completed by a team under the supervision of David Norton (Kaplan, Norton 2002. The developed method was used first of all to evaluate performance by decomposition of a strategy into four perspectives and identification of measures of achievement. In the middle of 1990s the method was improved by enriching it, first of all, with a strategy map, in which the process of transition of intangible assets into tangible financial effects is reflected (Kaplan, Norton 2001. Strategy map enables illustration of cause and effect relationship between processes in all four perspectives and performance indicators at the level of organization. The purpose of the study being prepared is to present methodical conditions of using strategy maps in the strategy implementation process in organizations of different nature.
Diagrammatic Monte Carlo method as applied to the polaron problem
International Nuclear Information System (INIS)
Mishchenko, A.S.
2005-01-01
Exact numerical solution methods for the problem of a few particles interacting with one another and with several bosonic excitation modes are presented. The diagrammatic Monte Carlo method allows the exact calculation of the Green function, and the stochastic optimization technique provides an analytic continuation. Results unobtainable by conventional methods are discussed, including the properties of excited states in the self-trapping phenomenon, the optical spectra of polarons in all coupling regimes, the validity analysis of the exciton models, and the photoemission spectra of a phonon-coupled hole [ru
Applying a life cycle approach to project management methods
Biggins, David; Trollsund, F.; Høiby, A.L.
2016-01-01
Project management is increasingly important to organisations because projects are the method\\ud by which organisations respond to their environment. A key element within project management\\ud is the standards and methods that are used to control and conduct projects, collectively known as\\ud project management methods (PMMs) and exemplified by PRINCE2, the Project Management\\ud Institute’s and the Association for Project Management’s Bodies of Knowledge (PMBOK and\\ud APMBOK. The purpose of t...
Method for curing alkyd resin compositions by applying ionizing radiation
International Nuclear Information System (INIS)
Watanabe, T.; Murata, K.; Maruyama, T.
1975-01-01
An alkyd resin composition is prepared by dissolving a polymerizable alkyd resin having from 10 to 50 percent of oil length into a vinyl monomer. The polymerizable alkyd resin is obtained by a half-esterification reaction of an acid anhydride having a polymerizable unsaturated group and an alkyd resin modified with conjugated unsaturated oil having at least one reactive hydroxyl group per one molecule. The alkyd resin composition thus obtained is coated on an article, and ionizing radiation is applied on the article to cure the coated film thereon. (U.S.)
Spectral methods applied to fluidized bed combustors. Final report
Energy Technology Data Exchange (ETDEWEB)
Brown, R.C.; Christofides, N.J.; Junk, K.W.; Raines, T.S.; Thiede, T.D.
1996-08-01
The objective of this project was to develop methods for characterizing fuels and sorbents from time-series data obtained during transient operation of fluidized bed boilers. These methods aimed at determining time constants for devolatilization and char burnout using carbon dioxide (CO{sub 2}) profiles and from time constants for the calcination and sulfation processes using CO{sub 2} and sulfur dioxide (SO{sub 2}) profiles.
Apply of torque method at rationalization of work
Directory of Open Access Journals (Sweden)
Bandurová Miriam
2001-03-01
Full Text Available Aim of the study was to analyse consumption of time for profession - cylinder grinder, by torque method.Method of torque following is used for detection of sorts and size of time slope, on detection of portion of individual sorts of time consumption and cause of time slope. By this way it is possible to find out coefficient of employment and recovery of workers in organizational unit. Advantage of torque survey is low costs on informations acquirement, non-fastidiousness per worker and observer, which is easy trained. It is mentally acceptable method for objects of survey.Finding and detection of reserves in activity of cylinders grinder result of torque was surveys. Loss of time presents till 8% of working time. In 5 - shift service and average occupiying of shift by 4,4 grinder ( from statistic information of service , loss at grinder of cylinders are for whole centre 1,48 worker.According presented information it was recommended to cancel one job place - grinder of cylinders - and reduce state about one grinder. Next job place isn't possible cancel, because grindery of cylinders must to adapt to the grind line by number of polished cylinders in shift and semi - finishing of polished cylinders can not be high for often changes in area of grinding and sortiment changes.By this contribution we confirmed convenience of exploitation of torque method as one of the methods using during the job rationalization.
Thermoluminescence as a dating method applied to the Morocco Neolithic
International Nuclear Information System (INIS)
Ousmoi, M.
1989-09-01
Thermoluminescence is an absolute dating method which is well adapted to the study of burnt clays and so of the prehistoric ceramics belonging to the Neolithic period. The purpose of this study is to establish a first absolute chronology of the septentrional morocco Neolithic between 3000 and 7000 years before us and some improvements of the TL dating. The first part of the thesis contains some hypothesis about the morocco Neolithic and some problems to solve. Then we study the TL dating method along with new process to ameliorate the quality of the results like the shift of quartz TL peaks or the crushing of samples. The methods which were employed using 24 samples belonging to various civilisations are: the quartz inclusion method and the fine grain technique. For the dosimetry, several methods were used: determination of the K 2 O contents, alpha counting, site dosimetry using TL dosimeters and a scintillation counter. The results which were found bring some interesting answers to the archeologic question and ameliorate the chronologic schema of the Northern morocco Neolithic: development of the old cardial Neolithic in the North, and perhaps in the center of Morocco (the region of Rabat), between 5500 and 7000 before us. Development of the recent middle Neolithic around 4000-5000 before us, with a protocampaniforme (Skhirat), little older than the campaniforme recognized in the south of Spain. Development of the bronze age around 2000-4000 before us [fr
Evaluation of Controller Tuning Methods Applied to Distillation Column Control
DEFF Research Database (Denmark)
Nielsen, Kim; W. Andersen, Henrik; Kümmel, Professor Mogens
A frequency domain approach is used to compare the nominal performance and robustness of dual composition distillation column control tuned according to Ziegler-Nichols (ZN) and Biggest Log Modulus Tuning (BLT) for three binary distillation columns, WOBE, LUVI and TOFA. The scope...... of this is to examine whether ZN and BLT design yield satisfactory control of distillation columns. Further, PI controllers are tuned according to a proposed multivariable frequency domain method. A major conclusion is that the ZN tuned controllers yield undesired overshoot and oscillation and poor stability robustness...... properties. BLT tuning removes the overshoot and oscillation, however, at the expense of a more sluggish response. We conclude that if a simple control design is to be used, the BLT method should be referred compared to the ZN method. The frequency domain design approach presented yields a more proper trade...
Modal method for crack identification applied to reactor recirculation pump
International Nuclear Information System (INIS)
Miller, W.H.; Brook, R.
1991-01-01
Nuclear reactors have been operating and producing useful electricity for many years. Within the last few years, several plants have found cracks in the reactor coolant pump shaft near the thermal barrier. The modal method and results described herein show the analytical results of using a Modal Analysis test method to determine the presence, size, and location of a shaft crack. The authors have previously demonstrated that the test method can analytically and experimentally identify shaft cracks as small as five percent (5%) of the shaft diameter. Due to small differences in material property distribution, the attempt to identify cracks smaller than 3% of the shaft diameter has been shown to be impractical. The rotor dynamics model includes a detailed motor rotor, external weights and inertias, and realistic total support stiffness. Results of the rotor dynamics model have been verified through a comparison with on-site vibration test data
Boron autoradiography method applied to the study of steels
International Nuclear Information System (INIS)
Gugelmeier, R.; Barcelo, G.N.; Boado, J.H.; Fernandez, C.
1986-01-01
The boron state, contained in the steel microestructure, is determined. The autoradiography by neutrons is used, permiting to obtain boron distribution images by means of additional information which is difficult to acquire by other methods. The application of the method is described, based on the neutronic irradiation of a polished steel sample, over which a celulose nitrate sheet or other appropriate material is fixed to constitute the detector. The particles generated by the neutron-boron interaction affect the detector sheet, which is subsequently revealed with a chemical treatment and can be observed at the optical microscope. In the case of materials used for the construction of nuclear reactors, special attention must be given to the presence of boron, since owing to the exceptionaly high capacity of neutron absorption, lowest quantities of boron acquire importance. The adaption of the method to metallurgical problems allows the obtainment of a correlation between the boron distribution images and the material's microstructure. (M.E.L.) [es
Diagrammatic Monte Carlo method as applied to the polaron problems
International Nuclear Information System (INIS)
Mishchenko, Andrei S
2005-01-01
Numerical methods whereby exact solutions to the problem of a few particles interacting with one another and with several bosonic excitation branches are presented. The diagrammatic Monte Carlo method allows the exact calculation of the Matsubara Green function, and the stochastic optimization technique provides an approximation-free analytic continuation. In this review, results unobtainable by conventional methods are discussed, including the properties of excited states in the self-trapping phenomenon, the optical spectra of polarons in all coupling regimes, the validity range analysis of the Frenkel and Wannier approximations relevant to the exciton, and the peculiarities of photoemission spectra of a lattice-coupled hole in a Mott insulator. (reviews of topical problems)
DAKOTA reliability methods applied to RAVEN/RELAP-7.
Energy Technology Data Exchange (ETDEWEB)
Swiler, Laura Painton; Mandelli, Diego; Rabiti, Cristian; Alfonsi, Andrea
2013-09-01
This report summarizes the result of a NEAMS project focused on the use of reliability methods within the RAVEN and RELAP-7 software framework for assessing failure probabilities as part of probabilistic risk assessment for nuclear power plants. RAVEN is a software tool under development at the Idaho National Laboratory that acts as the control logic driver and post-processing tool for the newly developed Thermal-Hydraulic code RELAP-7. Dakota is a software tool developed at Sandia National Laboratories containing optimization, sensitivity analysis, and uncertainty quantification algorithms. Reliability methods are algorithms which transform the uncertainty problem to an optimization problem to solve for the failure probability, given uncertainty on problem inputs and a failure threshold on an output response. The goal of this work is to demonstrate the use of reliability methods in Dakota with RAVEN/RELAP-7. These capabilities are demonstrated on a demonstration of a Station Blackout analysis of a simplified Pressurized Water Reactor (PWR).
Nonstandard Finite Difference Method Applied to a Linear Pharmacokinetics Model
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Oluwaseun Egbelowo
2017-05-01
Full Text Available We extend the nonstandard finite difference method of solution to the study of pharmacokinetic–pharmacodynamic models. Pharmacokinetic (PK models are commonly used to predict drug concentrations that drive controlled intravenous (I.V. transfers (or infusion and oral transfers while pharmacokinetic and pharmacodynamic (PD interaction models are used to provide predictions of drug concentrations affecting the response of these clinical drugs. We structure a nonstandard finite difference (NSFD scheme for the relevant system of equations which models this pharamcokinetic process. We compare the results obtained to standard methods. The scheme is dynamically consistent and reliable in replicating complex dynamic properties of the relevant continuous models for varying step sizes. This study provides assistance in understanding the long-term behavior of the drug in the system, and validation of the efficiency of the nonstandard finite difference scheme as the method of choice.
Variance reduction methods applied to deep-penetration problems
International Nuclear Information System (INIS)
Cramer, S.N.
1984-01-01
All deep-penetration Monte Carlo calculations require variance reduction methods. Before beginning with a detailed approach to these methods, several general comments concerning deep-penetration calculations by Monte Carlo, the associated variance reduction, and the similarities and differences of these with regard to non-deep-penetration problems will be addressed. The experienced practitioner of Monte Carlo methods will easily find exceptions to any of these generalities, but it is felt that these comments will aid the novice in understanding some of the basic ideas and nomenclature. Also, from a practical point of view, the discussions and developments presented are oriented toward use of the computer codes which are presented in segments of this Monte Carlo course
Robustness of Modal Parameter Estimation Methods Applied to Lightweight Structures
DEFF Research Database (Denmark)
Dickow, Kristoffer Ahrens; Kirkegaard, Poul Henning; Andersen, Lars Vabbersgaard
2013-01-01
of two parameter estimation methods built into the commercial modal testing software B&K Pulse Re ex Advanced Modal Analysis. The investigations are done by means of frequency response functions generated from a nite-element model and subjected to articial noise before being analyzed with Pulse Re ex....... The ability to handle closely spaced modes and broad frequency ranges is investigated for a numerical model of a lightweight junction under dierent signal-to-noise ratios. The selection of both excitation points and response points are discussed. It is found that both the Rational Fraction Polynomial-Z method...
Efficient electronic structure methods applied to metal nanoparticles
DEFF Research Database (Denmark)
Larsen, Ask Hjorth
of efficient approaches to density functional theory and the application of these methods to metal nanoparticles. We describe the formalism and implementation of localized atom-centered basis sets within the projector augmented wave method. Basis sets allow for a dramatic increase in performance compared...... and jumps in Fermi level near magic numbers can lead to alkali-like or halogen-like behaviour when main-group atoms adsorb onto gold clusters. A non-self-consistent NewnsAnderson model is used to more closely study the chemisorption of main-group atoms on magic-number Au clusters. The behaviour at magic...
Applying the Priority Distribution Method for Employee Motivation
Directory of Open Access Journals (Sweden)
Jonas Žaptorius
2013-09-01
Full Text Available In an age of increasing healthcare expenditure, the efficiency of healthcare services is a burning issue. This paper deals with the creation of a performance-related remuneration system, which would meet requirements for efficiency and sustainable quality. In real world scenarios, it is difficult to create an objective and transparent employee performance evaluation model dealing with both qualitative and quantitative criteria. To achieve these goals, the use of decision support methods is suggested and analysed. The systematic approach of practical application of the Priority Distribution Method to healthcare provider organisations is created and described.
Non-perturbative methods applied to multiphoton ionization
International Nuclear Information System (INIS)
Brandi, H.S.; Davidovich, L.; Zagury, N.
1982-09-01
The use of non-perturbative methods in the treatment of atomic ionization is discussed. Particular attention is given to schemes of the type proposed by Keldysh where multiphoton ionization and tunnel auto-ionization occur for high intensity fields. These methods are shown to correspond to a certain type of expansion of the T-matrix in the intra-atomic potential; in this manner a criterium concerning the range of application of these non-perturbative schemes is suggested. A brief comparison between the ionization rate of atoms in the presence of linearly and circularly polarized light is presented. (Author) [pt
Tutte’s barycenter method applied to isotopies
Colin de Verdière, Éric; Pocchiola, Michel; Vegter, Gert
2003-01-01
This paper is concerned with applications of Tutte’s barycentric embedding theorem. It presents a method for building isotopies of triangulations in the plane, based on Tutte’s theorem and the computation of equilibrium stresses of graphs by Maxwell–Cremona’s theorem; it also provides a
Inversion method applied to the rotation curves of galaxies
Márquez-Caicedo, L. A.; Lora-Clavijo, F. D.; Sanabria-Gómez, J. D.
2017-07-01
We used simulated annealing, Montecarlo and genetic algorithm methods for matching both numerical data of density and velocity profiles in some low surface brigthness galaxies with theoretical models of Boehmer-Harko, Navarro-Frenk-White and Pseudo Isothermal Profiles for galaxies with dark matter halos. We found that Navarro-Frenk-White model does not fit at all in contrast with the other two models which fit very well. Inversion methods have been widely used in various branches of science including astrophysics (Charbonneau 1995, ApJS, 101, 309). In this work we have used three different parametric inversion methods (MonteCarlo, Genetic Algorithm and Simmulated Annealing) in order to determine the best fit of the observed data of the density and velocity profiles of a set of low surface brigthness galaxies (De Block et al. 2001, ApJ, 122, 2396) with three models of galaxies containing dark mattter. The parameters adjusted by the inversion methods were the central density and a characteristic distance in the Boehmer-Harko BH (Boehmer & Harko 2007, JCAP, 6, 25), Navarro-Frenk-White NFW (Navarro et al. 2007, ApJ, 490, 493) and Pseudo Isothermal Profile PI (Robles & Matos 2012, MNRAS, 422, 282). The results obtained showed that the BH and PI Profile dark matter galaxies fit very well for both the density and the velocity profiles, in contrast the NFW model did not make good adjustments to the profiles in any analized galaxy.
E-LEARNING METHOD APPLIED TO TECHNICAL GRAPHICS SUBJECTS
Directory of Open Access Journals (Sweden)
GOANTA Adrian Mihai
2011-11-01
Full Text Available The paper presents some of the author’s endeavors in creating video courses for the students from the Faculty of Engineering in Braila related to subjects involving technical graphics . There are also mentioned the steps taken in completing the method and how to achieve a feedback on the rate of access to these types of courses by the students.
Some methods of computational geometry applied to computer graphics
Overmars, M.H.; Edelsbrunner, H.; Seidel, R.
1984-01-01
Abstract Windowing a two-dimensional picture means to determine those line segments of the picture that are visible through an axis-parallel window. A study of some algorithmic problems involved in windowing a picture is offered. Some methods from computational geometry are exploited to store the
[Synchrotron-based characterization methods applied to ancient materials (I)].
Anheim, Étienne; Thoury, Mathieu; Bertrand, Loïc
2015-12-01
This article aims at presenting the first results of a transdisciplinary research programme in heritage sciences. Based on the growing use and on the potentialities of micro- and nano-characterization synchrotron-based methods to study ancient materials (archaeology, palaeontology, cultural heritage, past environments), this contribution will identify and test conceptual and methodological elements of convergence between physicochemical and historical sciences.
About the Finite Element Method Applied to Thick Plates
Directory of Open Access Journals (Sweden)
Mihaela Ibănescu
2006-01-01
Full Text Available The present paper approaches of plates subjected to transverse loads, when the shear force and the actual boundary conditions are considered, by using the Finite Element Method. The isoparametric finite elements create real facilities in formulating the problems and great possibilities in creating adequate computer programs.
The harmonics detection method based on neural network applied ...
African Journals Online (AJOL)
user
with MATLAB Simulink Power System Toolbox. The simulation study results of this novel technique compared to other similar methods are found quite satisfactory by assuring good filtering characteristics and high system stability. Keywords: Artificial Neural Networks (ANN), p-q theory, (SAPF), Harmonics, Total Harmonic ...
Stolzer, Alan J.; Halford, Carl
2007-01-01
In a previous study, multiple regression techniques were applied to Flight Operations Quality Assurance-derived data to develop parsimonious model(s) for fuel consumption on the Boeing 757 airplane. The present study examined several data mining algorithms, including neural networks, on the fuel consumption problem and compared them to the multiple regression results obtained earlier. Using regression methods, parsimonious models were obtained that explained approximately 85% of the variation in fuel flow. In general data mining methods were more effective in predicting fuel consumption. Classification and Regression Tree methods reported correlation coefficients of .91 to .92, and General Linear Models and Multilayer Perceptron neural networks reported correlation coefficients of about .99. These data mining models show great promise for use in further examining large FOQA databases for operational and safety improvements.
Theoretical and applied aerodynamics and related numerical methods
Chattot, J J
2015-01-01
This book covers classical and modern aerodynamics, theories and related numerical methods, for senior and first-year graduate engineering students, including: -The classical potential (incompressible) flow theories for low speed aerodynamics of thin airfoils and high and low aspect ratio wings. - The linearized theories for compressible subsonic and supersonic aerodynamics. - The nonlinear transonic small disturbance potential flow theory, including supercritical wing sections, the extended transonic area rule with lift effect, transonic lifting line and swept or oblique wings to minimize wave drag. Unsteady flow is also briefly discussed. Numerical simulations based on relaxation mixed-finite difference methods are presented and explained. - Boundary layer theory for all Mach number regimes and viscous/inviscid interaction procedures used in practical aerodynamics calculations. There are also four chapters covering special topics, including wind turbines and propellers, airplane design, flow analogies and h...
Generic Methods for Formalising Sequent Calculi Applied to Provability Logic
Dawson, Jeremy E.; Goré, Rajeev
We describe generic methods for reasoning about multiset-based sequent calculi which allow us to combine shallow and deep embeddings as desired. Our methods are modular, permit explicit structural rules, and are widely applicable to many sequent systems, even to other styles of calculi like natural deduction and term rewriting systems. We describe new axiomatic type classes which enable simplification of multiset or sequent expressions using existing algebraic manipulation facilities. We demonstrate the benefits of our combined approach by formalising in Isabelle/HOL a variant of a recent, non-trivial, pen-and-paper proof of cut-admissibility for the provability logic GL, where we abstract a large part of the proof in a way which is immediately applicable to other calculi. Our work also provides a machine-checked proof to settle the controversy surrounding the proof of cut-admissibility for GL.
Hamilton, H. B.; Strangas, E.
1980-01-01
The time dependent solution of the magnetic field is introduced as a method for accounting for the variation, in time, of the machine parameters in predicting and analyzing the performance of the electrical machines. The method of time dependent finite element was used in combination with an also time dependent construction of a grid for the air gap region. The Maxwell stress tensor was used to calculate the airgap torque from the magnetic vector potential distribution. Incremental inductances were defined and calculated as functions of time, depending on eddy currents and saturation. The currents in all the machine circuits were calculated in the time domain based on these inductances, which were continuously updated. The method was applied to a chopper controlled DC series motor used for electric vehicle drive, and to a salient pole sychronous motor with damper bars. Simulation results were compared to experimentally obtained ones.
Applying probabilistic methods for assessments and calculations for accident prevention
International Nuclear Information System (INIS)
Anon.
1984-01-01
The guidelines for the prevention of accidents require plant design-specific and radioecological calculations to be made in order to show that maximum acceptable expsoure values will not be exceeded in case of an accident. For this purpose, main parameters affecting the accident scenario have to be determined by probabilistic methods. This offers the advantage that parameters can be quantified on the basis of unambigious and realistic criteria, and final results can be defined in terms of conservativity. (DG) [de
The transfer matrix method applied to steel sheet pile walls
Kort, D. A.
2003-05-01
This paper proposes two subgrade reaction models for the analysis of steel sheet pile walls based on the transfer matrix method. In the first model a plastic hinge is generated when the maximum moment in the retaining structure is exceeded. The second model deals with a beam with an asymmetrical cross-section that can bend in two directions.In the first part of this paper the transfer matrix method is explained on the basis of a simple example. Further the development of two computer models is described: Plaswall and Skewwall.The second part of this paper deals with an application of both models. In the application of Plaswall the effect of four current earth pressure theories to the subgrade reaction method is compared to a finite element calculation. It is shown that the earth pressure theory is of major importance on the calculation result of a sheet pile wall both with and without a plastic hinge.In the application of Skewwall the effectiveness of structural measures to reduce oblique bending is investigated. The results are compared to a 3D finite element calculation. It is shown that with simple structural measures the loss of structural resistance due to oblique bending can be reduced.
Applying Hierarchical Task Analysis Method to Discovery Layer Evaluation
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Marlen Promann
2015-03-01
Full Text Available Libraries are implementing discovery layers to offer better user experiences. While usability tests have been helpful in evaluating the success or failure of implementing discovery layers in the library context, the focus has remained on its relative interface benefits over the traditional federated search. The informal site- and context specific usability tests have offered little to test the rigor of the discovery layers against the user goals, motivations and workflow they have been designed to support. This study proposes hierarchical task analysis (HTA as an important complementary evaluation method to usability testing of discovery layers. Relevant literature is reviewed for the discovery layers and the HTA method. As no previous application of HTA to the evaluation of discovery layers was found, this paper presents the application of HTA as an expert based and workflow centered (e.g. retrieving a relevant book or a journal article method to evaluating discovery layers. Purdue University’s Primo by Ex Libris was used to map eleven use cases as HTA charts. Nielsen’s Goal Composition theory was used as an analytical framework to evaluate the goal carts from two perspectives: a users’ physical interactions (i.e. clicks, and b user’s cognitive steps (i.e. decision points for what to do next. A brief comparison of HTA and usability test findings is offered as a way of conclusion.
System and method of applying energetic ions for sterilization
Schmidt, John A.
2003-12-23
A method of sterilization of a container is provided whereby a cold plasma is caused to be disposed near a surface to be sterilized, and the cold plasma is then subjected to a pulsed voltage differential for producing energized ions in the plasma. Those energized ions then operate to achieve spore destruction on the surface to be sterilized. Further, a system for sterilization of a container which includes a conductive or non-conductive container, a cold plasma in proximity to the container, and a high voltage source for delivering a pulsed voltage differential between an electrode and the container and across the cold plasma, is provided.
Interesting Developments in Testing Methods Applied to Foundation Piles
Sobala, Dariusz; Tkaczyński, Grzegorz
2017-10-01
Both: piling technologies and pile testing methods are a subject of current development. New technologies, providing larger diameters or using in-situ materials, are very demanding in terms of providing proper quality of execution of works. That concerns the material quality and continuity which define the integral strength of pile. On the other side we have the capacity of the ground around the pile and its ability to carry the loads transferred by shaft and pile base. Inhomogeneous nature of soils and a relatively small amount of tested piles imposes very good understanding of small amount of results. In some special cases the capacity test itself form an important cost in the piling contract. This work presents a brief description of selected testing methods and authors remarks based on cooperation with Universities constantly developing new ideas. Paper presents some experience based remarks on integrity testing by means of low energy impact (low strain) and introduces selected (Polish) developments in the field of closed-end pipe piles testing based on bi-directional loading, similar to Osterberg idea, but without sacrificial hydraulic jack. Such test is suitable especially when steel piles are used for temporary support in the rivers, where constructing of conventional testing appliance with anchor piles or kentledge meets technical problems. According to the author’s experience, such tests were not yet used on the building site but they bring a real potential especially, when the displacement control can be provided from the river bank using surveying techniques.
Benchmark Comparison of Cloud Analytics Methods Applied to Earth Observations
Lynnes, Chris; Little, Mike; Huang, Thomas; Jacob, Joseph; Yang, Phil; Kuo, Kwo-Sen
2016-01-01
Cloud computing has the potential to bring high performance computing capabilities to the average science researcher. However, in order to take full advantage of cloud capabilities, the science data used in the analysis must often be reorganized. This typically involves sharding the data across multiple nodes to enable relatively fine-grained parallelism. This can be either via cloud-based file systems or cloud-enabled databases such as Cassandra, Rasdaman or SciDB. Since storing an extra copy of data leads to increased cost and data management complexity, NASA is interested in determining the benefits and costs of various cloud analytics methods for real Earth Observation cases. Accordingly, NASA's Earth Science Technology Office and Earth Science Data and Information Systems project have teamed with cloud analytics practitioners to run a benchmark comparison on cloud analytics methods using the same input data and analysis algorithms. We have particularly looked at analysis algorithms that work over long time series, because these are particularly intractable for many Earth Observation datasets which typically store data with one or just a few time steps per file. This post will present side-by-side cost and performance results for several common Earth observation analysis operations.
Artificial Intelligence Methods Applied to Parameter Detection of Atrial Fibrillation
Arotaritei, D.; Rotariu, C.
2015-09-01
In this paper we present a novel method to develop an atrial fibrillation (AF) based on statistical descriptors and hybrid neuro-fuzzy and crisp system. The inference of system produce rules of type if-then-else that care extracted to construct a binary decision system: normal of atrial fibrillation. We use TPR (Turning Point Ratio), SE (Shannon Entropy) and RMSSD (Root Mean Square of Successive Differences) along with a new descriptor, Teager- Kaiser energy, in order to improve the accuracy of detection. The descriptors are calculated over a sliding window that produce very large number of vectors (massive dataset) used by classifier. The length of window is a crisp descriptor meanwhile the rest of descriptors are interval-valued type. The parameters of hybrid system are adapted using Genetic Algorithm (GA) algorithm with fitness single objective target: highest values for sensibility and sensitivity. The rules are extracted and they are part of the decision system. The proposed method was tested using the Physionet MIT-BIH Atrial Fibrillation Database and the experimental results revealed a good accuracy of AF detection in terms of sensitivity and specificity (above 90%).
Modern analytic methods applied to the art and archaeology
International Nuclear Information System (INIS)
Tenorio C, M. D.; Longoria G, L. C.
2010-01-01
The interaction of diverse areas as the analytic chemistry, the history of the art and the archaeology has allowed the development of a variety of techniques used in archaeology, in conservation and restoration. These methods have been used to date objects, to determine the origin of the old materials and to reconstruct their use and to identify the degradation processes that affect the integrity of the art works. The objective of this chapter is to offer a general vision on the researches that have been realized in the Instituto Nacional de Investigaciones Nucleares (ININ) in the field of cultural goods. A series of researches carried out in collaboration with national investigators and of the foreigner is described shortly, as well as with the great support of degree students and master in archaeology of the National School of Anthropology and History, since one of the goals that have is to diffuse the knowledge of the existence of these techniques among the young archaeologists, so that they have a wider vision of what they could use in an in mediate future and they can check hypothesis with scientific methods. (Author)
Benchmark Comparison of Cloud Analytics Methods Applied to Earth Observations
Lynnes, C.; Little, M. M.; Huang, T.; Jacob, J. C.; Yang, C. P.; Kuo, K. S.
2016-12-01
Cloud computing has the potential to bring high performance computing capabilities to the average science researcher. However, in order to take full advantage of cloud capabilities, the science data used in the analysis must often be reorganized. This typically involves sharding the data across multiple nodes to enable relatively fine-grained parallelism. This can be either via cloud-based filesystems or cloud-enabled databases such as Cassandra, Rasdaman or SciDB. Since storing an extra copy of data leads to increased cost and data management complexity, NASA is interested in determining the benefits and costs of various cloud analytics methods for real Earth Observation cases. Accordingly, NASA's Earth Science Technology Office and Earth Science Data and Information Systems project have teamed with cloud analytics practitioners to run a benchmark comparison on cloud analytics methods using the same input data and analysis algorithms. We have particularly looked at analysis algorithms that work over long time series, because these are particularly intractable for many Earth Observation datasets which typically store data with one or just a few time steps per file. This post will present side-by-side cost and performance results for several common Earth observation analysis operations.
Energy Technology Data Exchange (ETDEWEB)
Okur, S. [Physics Department, Izmir Institute of Technology (Turkey)], E-mail: salihokur@iyte.edu.tr; Kalkanci, M. [Material Science Program, Izmir Institute of Technology (Turkey); Pat, S.; Ekem, N.; Akan, T. [Physics Department, Osmangazi University (Turkey); Balbag, Z. [Department of Science and Mathematics Education, Osmangazi University (Turkey); Musa, G. [Plasma and Radiation, National Institute for Physics of Laser (Romania); Tanoglu, M. [Mechanical Engineering Department, Izmir Institute of Technology (Turkey)
2007-11-01
In this work, we discuss fabrication and characterization of MgB{sub 2} thin films obtained by sequential deposition and annealing of sandwich like Mg/B/Mg thin films on glass substrates. Mg and B films were prepared using DC magnetron sputtering and thermionic vacuum arc techniques, respectively. The MgB{sub 2} thin films showed superconducting critical transition at 33 K after annealing at 650 deg. C.
The Movable Type Method Applied to Protein-Ligand Binding.
Zheng, Zheng; Ucisik, Melek N; Merz, Kenneth M
2013-12-10
Accurately computing the free energy for biological processes like protein folding or protein-ligand association remains a challenging problem. Both describing the complex intermolecular forces involved and sampling the requisite configuration space make understanding these processes innately difficult. Herein, we address the sampling problem using a novel methodology we term "movable type". Conceptually it can be understood by analogy with the evolution of printing and, hence, the name movable type. For example, a common approach to the study of protein-ligand complexation involves taking a database of intact drug-like molecules and exhaustively docking them into a binding pocket. This is reminiscent of early woodblock printing where each page had to be laboriously created prior to printing a book. However, printing evolved to an approach where a database of symbols (letters, numerals, etc.) was created and then assembled using a movable type system, which allowed for the creation of all possible combinations of symbols on a given page, thereby, revolutionizing the dissemination of knowledge. Our movable type (MT) method involves the identification of all atom pairs seen in protein-ligand complexes and then creating two databases: one with their associated pairwise distant dependent energies and another associated with the probability of how these pairs can combine in terms of bonds, angles, dihedrals and non-bonded interactions. Combining these two databases coupled with the principles of statistical mechanics allows us to accurately estimate binding free energies as well as the pose of a ligand in a receptor. This method, by its mathematical construction, samples all of configuration space of a selected region (the protein active site here) in one shot without resorting to brute force sampling schemes involving Monte Carlo, genetic algorithms or molecular dynamics simulations making the methodology extremely efficient. Importantly, this method explores the free
Applied statistical methods in agriculture, health and life sciences
Lawal, Bayo
2014-01-01
This textbook teaches crucial statistical methods to answer research questions using a unique range of statistical software programs, including MINITAB and R. This textbook is developed for undergraduate students in agriculture, nursing, biology and biomedical research. Graduate students will also find it to be a useful way to refresh their statistics skills and to reference software options. The unique combination of examples is approached using MINITAB and R for their individual strengths. Subjects covered include among others data description, probability distributions, experimental design, regression analysis, randomized design and biological assay. Unlike other biostatistics textbooks, this text also includes outliers, influential observations in regression and an introduction to survival analysis. Material is taken from the author's extensive teaching and research in Africa, USA and the UK. Sample problems, references and electronic supplementary material accompany each chapter.
Applying Simulation Method in Formulation of Gluten-Free Cookies
Directory of Open Access Journals (Sweden)
Nikitina Marina
2017-01-01
Full Text Available At present time priority direction in the development of new food products its developing of technology products for special purposes. These types of products are gluten-free confectionery products, intended for people with celiac disease. Gluten-free products are in demand among consumers, it needs to expand assortment, and improvement of quality indicators. At this article results of studies on the development of pastry products based on amaranth flour does not contain gluten. Study based on method of simulation recipes gluten-free confectionery functional orientation to optimize their chemical composition. The resulting products will allow to diversify and supplement the necessary nutrients diet for people with gluten intolerance, as well as for those who follow a gluten-free diet.
Applying Human-Centered Design Methods to Scientific Communication Products
Burkett, E. R.; Jayanty, N. K.; DeGroot, R. M.
2016-12-01
Knowing your users is a critical part of developing anything to be used or experienced by a human being. User interviews, journey maps, and personas are all techniques commonly employed in human-centered design practices because they have proven effective for informing the design of products and services that meet the needs of users. Many non-designers are unaware of the usefulness of personas and journey maps. Scientists who are interested in developing more effective products and communication can adopt and employ user-centered design approaches to better reach intended audiences. Journey mapping is a qualitative data-collection method that captures the story of a user's experience over time as related to the situation or product that requires development or improvement. Journey maps help define user expectations, where they are coming from, what they want to achieve, what questions they have, their challenges, and the gaps and opportunities that can be addressed by designing for them. A persona is a tool used to describe the goals and behavioral patterns of a subset of potential users or customers. The persona is a qualitative data model that takes the form of a character profile, built upon data about the behaviors and needs of multiple users. Gathering data directly from users avoids the risk of basing models on assumptions, which are often limited by misconceptions or gaps in understanding. Journey maps and user interviews together provide the data necessary to build the composite character that is the persona. Because a persona models the behaviors and needs of the target audience, it can then be used to make informed product design decisions. We share the methods and advantages of developing and using personas and journey maps to create more effective science communication products.
Simplified Methods Applied to Nonlinear Motion of Spar Platforms
Energy Technology Data Exchange (ETDEWEB)
Haslum, Herbjoern Alf
2000-07-01
Simplified methods for prediction of motion response of spar platforms are presented. The methods are based on first and second order potential theory. Nonlinear drag loads and the effect of the pumping motion in a moon-pool are also considered. Large amplitude pitch motions coupled to extreme amplitude heave motions may arise when spar platforms are exposed to long period swell. The phenomenon is investigated theoretically and explained as a Mathieu instability. It is caused by nonlinear coupling effects between heave, surge, and pitch. It is shown that for a critical wave period, the envelope of the heave motion makes the pitch motion unstable. For the same wave period, a higher order pitch/heave coupling excites resonant heave response. This mutual interaction largely amplifies both the pitch and the heave response. As a result, the pitch/heave instability revealed in this work is more critical than the previously well known Mathieu's instability in pitch which occurs if the wave period (or the natural heave period) is half the natural pitch period. The Mathieu instability is demonstrated both by numerical simulations with a newly developed calculation tool and in model experiments. In order to learn more about the conditions for this instability to occur and also how it may be controlled, different damping configurations (heave damping disks and pitch/surge damping fins) are evaluated both in model experiments and by numerical simulations. With increased drag damping, larger wave amplitudes and more time are needed to trigger the instability. The pitch/heave instability is a low probability of occurrence phenomenon. Extreme wave periods are needed for the instability to be triggered, about 20 seconds for a typical 200m draft spar. However, it may be important to consider the phenomenon in design since the pitch/heave instability is very critical. It is also seen that when classical spar platforms (constant cylindrical cross section and about 200m draft
Perturbation Method of Analysis Applied to Substitution Measurements of Buckling
Energy Technology Data Exchange (ETDEWEB)
Persson, Rolf
1966-11-15
Calculations with two-group perturbation theory on substitution experiments with homogenized regions show that a condensation of the results into a one-group formula is possible, provided that a transition region is introduced in a proper way. In heterogeneous cores the transition region comes in as a consequence of a new cell concept. By making use of progressive substitutions the properties of the transition region can be regarded as fitting parameters in the evaluation procedure. The thickness of the region is approximately equal to the sum of 1/(1/{tau} + 1/L{sup 2}){sup 1/2} for the test and reference regions. Consequently a region where L{sup 2} >> {tau}, e.g. D{sub 2}O, contributes with {radical}{tau} to the thickness. In cores where {tau} >> L{sup 2} , e.g. H{sub 2}O assemblies, the thickness of the transition region is determined by L. Experiments on rod lattices in D{sub 2}O and on test regions of D{sub 2}O alone (where B{sup 2} = - 1/L{sup 2} ) are analysed. The lattice measurements, where the pitches differed by a factor of {radical}2, gave excellent results, whereas the determination of the diffusion length in D{sub 2}O by this method was not quite successful. Even regions containing only one test element can be used in a meaningful way in the analysis.
Variational methods applied to problems of diffusion and reaction
Strieder, William
1973-01-01
This monograph is an account of some problems involving diffusion or diffusion with simultaneous reaction that can be illuminated by the use of variational principles. It was written during a period that included sabbatical leaves of one of us (W. S. ) at the University of Minnesota and the other (R. A. ) at the University of Cambridge and we are grateful to the Petroleum Research Fund for helping to support the former and the Guggenheim Foundation for making possible the latter. We would also like to thank Stephen Prager for getting us together in the first place and for showing how interesting and useful these methods can be. We have also benefitted from correspondence with Dr. A. M. Arthurs of the University of York and from the counsel of Dr. B. D. Coleman the general editor of this series. Table of Contents Chapter 1. Introduction and Preliminaries . 1. 1. General Survey 1 1. 2. Phenomenological Descriptions of Diffusion and Reaction 2 1. 3. Correlation Functions for Random Suspensions 4 1. 4. Mean Free ...
Nondestructive methods of analysis applied to oriental swords
Directory of Open Access Journals (Sweden)
Edge, David
2015-12-01
Full Text Available Various neutron techniques were employed at the Budapest Nuclear Centre in an attempt to find the most useful method for analysing the high-carbon steels found in Oriental arms and armour, such as those in the Wallace Collection, London. Neutron diffraction was found to be the most useful in terms of identifying such steels and also indicating the presence of hidden patternEn el Centro Nuclear de Budapest se han empleado varias técnicas neutrónicas con el fin de encontrar un método adecuado para analizar las armas y armaduras orientales con un alto contenido en carbono, como algunas de las que se encuentran en la Colección Wallace de Londres. El empleo de la difracción de neutrones resultó ser la técnica más útil de cara a identificar ese tipo de aceros y también para encontrar patrones escondidos.
DC Home Appliances for DC Distribution System
Directory of Open Access Journals (Sweden)
MUHAMMAD KAMRAN
2017-10-01
Full Text Available This paper strengthens the idea of DC distribution system for DC microgrid consisting of a building of 50 apartments. Since the war of currents AC system has been dominant because of the paucity of research in the protection of the DC system. Now with the advance research in power electronics material and components, generation of electricity is inherently DC as by solar PV, fuel cell and thermoelectric generator that eliminates the rectification process. Transformers are replaced by the power electronics buck-boost converters. DC circuit breakers have solved the protection problems for both DC transmission and distribution system. In this paper 308V DC microgrid is proposed and home appliances (DC internal are modified to operate on 48V DC from DC distribution line. Instead of using universal and induction motors in rotary appliances, BLDC (Brushless DC motors are proposed that are highly efficient with minimum electro-mechanical and no commutation losses. Proposed DC system reduces the power conversion stages, hence diminishes the associated power losses and standby losses that boost the overall system efficiency. So in view of all this a conventional AC system can be replaced by a DC system that has many advantages by cost as well as by performance
Detection of high-impedance fault in low-voltage DC distribution system via mathematical morphology
Directory of Open Access Journals (Sweden)
Yun-Sik Oh
2016-01-01
Full Text Available This study presents a method for high-impedance fault (HIF detection in a low-voltage DC (LVDC distribution system via mathematical morphology (MM, which is composed of two elementary transformations, namely, dilation and erosion. Various MM-based filters are used to detect abnormal signals of current waveform. The LVDC distribution system, including power conversion devices, such as AC/DC and DC/DC converters, is modelled with electromagnetic transient program (EMTP software to verify the proposed method. The HIF arc model in the DC system is also implemented with EMTP/MODELS, which is a symbolic language interpreter for EMTP. Simulation results show that the proposed method can be applied to detect HIF effectively in the LVDC distribution system.
Complexity methods applied to turbulence in plasma astrophysics
Vlahos, L.; Isliker, H.
2016-09-01
In this review many of the well known tools for the analysis of Complex systems are used in order to study the global coupling of the turbulent convection zone with the solar atmosphere where the magnetic energy is dissipated explosively. Several well documented observations are not easy to interpret with the use of Magnetohydrodynamic (MHD) and/or Kinetic numerical codes. Such observations are: (1) The size distribution of the Active Regions (AR) on the solar surface, (2) The fractal and multi fractal characteristics of the observed magnetograms, (3) The Self-Organised characteristics of the explosive magnetic energy release and (4) the very efficient acceleration of particles during the flaring periods in the solar corona. We review briefly the work published the last twenty five years on the above issues and propose solutions by using methods borrowed from the analysis of complex systems. The scenario which emerged is as follows: (a) The fully developed turbulence in the convection zone generates and transports magnetic flux tubes to the solar surface. Using probabilistic percolation models we were able to reproduce the size distribution and the fractal properties of the emerged and randomly moving magnetic flux tubes. (b) Using a Non Linear Force Free (NLFF) magnetic extrapolation numerical code we can explore how the emerged magnetic flux tubes interact nonlinearly and form thin and Unstable Current Sheets (UCS) inside the coronal part of the AR. (c) The fragmentation of the UCS and the redistribution of the magnetic field locally, when the local current exceeds a Critical threshold, is a key process which drives avalanches and forms coherent structures. This local reorganization of the magnetic field enhances the energy dissipation and influences the global evolution of the complex magnetic topology. Using a Cellular Automaton and following the simple rules of Self Organized Criticality (SOC), we were able to reproduce the statistical characteristics of the
Huang, Peter Jen-Hung
This research first proposes a method to merge photovoltaic (PV) cells or PV panels within the internal components DC-DC converters. The purpose of this merged structure is to reconfigure the PV modules between series and parallel connections using high switching frequencies (hundreds of kHz). This leads to multi-levels of voltages and currents that become applied to the output filter of the converter. Further, this research introduces a concept of a switching cell that utilizes the reconfiguration of series and parallel connections in DC-DC converters. The switching occurs at high switching frequency and the switches can be integrated to be within the solar panels or in between the solar cells. The concept is generalized and applied to basic buck and boost topologies. As examples of the new types of converters: reconfigurable PV-buck and PV-boost converter topologies are presented. It is also possible to create other reconfigurable power converters: non-isolated and isolated topologies. Analysis, simulation and experimental verification for the reconfigurable PV-buck and PV-boost converters are presented extensively to illustrate proof of concept. Benefits and drawbacks of the new approach are discussed. The second part of this research proposes to utilize the internal solar cell capacitance and internal solar module wire parasitic inductances to replace the input capacitor and filter inductor in boost derived DC-DC converters for energy harvesting applications. High switching frequency (MHz) hard switched and resonant boost converters are proposed. Their analysis, simulation and experimental prototypes are presented. A specific proof-of-concept application is especially tested for foldable PV panels, which are known for their high internal wire inductance. The experimental converters successfully boost solar module voltage without adding any external input capacitance or filter inductor. Benefits and drawbacks of new proposed PV submodule integrated boost
Fuzzy Control of DC-DC Converters with Input Constraint
Directory of Open Access Journals (Sweden)
D. Saifia
2012-01-01
Full Text Available This paper proposes a method for designing fuzzy control of DC-DC converters under actuator saturation. Because linear control design methods do not take into account the nonlinearity of the system, a T-S fuzzy model and a controller design approach is used. The designed control not only handles the external disturbance but also the saturation of duty cycle. The input constraint is first transformed into a symmetric saturation which is represented by a polytopic model. Stabilization conditions for the state feedback system of DC-DC converters under actuator saturation are established using the Lyapunov approach. The proposed method has been compared and verified with a simulation example.
A Double Phase-Shift Control Strategy for A Full-Bridge Three-Level DC/DC Converter
DEFF Research Database (Denmark)
Liu, Dong; Deng, Fujin; Gong, Zheng
2016-01-01
In this paper, a double phase-shift control strategy is proposed for the full-bridge three-level (FBTL) DC/DC converter applied into DC distribution systems with the medium DC bus voltage. By utilizing the proposed control strategy, the voltage change rate dv/dt and voltage stress of the transfor...
Lukemire, Alan T.
1992-01-01
Dc-to-dc power-converter circuits called "forback" resemble circuits of standard configurations called "forward", "flyback", and "Cuk". Circuit employs minor modifications to existing topologies, combines advantages, while eliminating disadvantages, of older circuits.
Energy Technology Data Exchange (ETDEWEB)
Pustode, Mangesh D. [Bharat Forge Ltd., Pune (India); Dewangan, Bhupendra [Tata Steel, Jamshedpur (India); Raja, V. S. [Indian Institute of Technology Bombay, Mumbai (India); Paulose, Neeta; Babu, Narendra [Gas Turbine Research Establishment (GTRE), Bangalore (India)
2016-10-15
DC potential drop technique was employed during the slow strain rate tests to study the hot salt stress corrosion crack (HSSCC) initiation at 300 and 400 ℃. Threshold stresses for HSSCC initiation were found to about 88 % of the yield strength at both temperatures, but the time from crack initiation to final failure (Δtscc) decreased significantly with temperature, which reflects larger tendency for brittle fracture and secondary cracking. The brittle fracture features consisted of transgranular cracking through the primary α grain and discontinuous faceted cracking through the transformed β grains.
Kimura, Akira
In inverter-converter driving systems for AC electric cars, the DC input voltage of an inverter contains a ripple component with a frequency that is twice as high as the line voltage frequency, because of a single-phase converter. The ripple component of the inverter input voltage causes pulsations on torques and currents of driving motors. To decrease the pulsations, a beat-less control method, which modifies a slip frequency depending on the ripple component, is applied to the inverter control. In the present paper, the beat-less control method was analyzed in the frequency domain. In the first step of the analysis, transfer functions, which revealed the relationship among the ripple component of the inverter input voltage, the slip frequency, the motor torque pulsation and the current pulsation, were derived with a synchronous rotating model of induction motors. An analysis model of the beat-less control method was then constructed using the transfer functions. The optimal setting of the control method was obtained according to the analysis model. The transfer functions and the analysis model were verified through simulations.
DC electric springs with DC/DC converters
DEFF Research Database (Denmark)
Wang, Qingsong; Cheng, Ming; Jiang, Yunlei
2016-01-01
The concept of DC electric spring (DCES) was recently proposed to solve the stability issue caused by integrating intermittent renewable energy sources (RESs) to DC microgrids. In this paper, a new topology of DCES is proposed based on DC/DC converters. The proposed DCES consists of a bi-directio......The concept of DC electric spring (DCES) was recently proposed to solve the stability issue caused by integrating intermittent renewable energy sources (RESs) to DC microgrids. In this paper, a new topology of DCES is proposed based on DC/DC converters. The proposed DCES consists of a bi...... and/or constant discharging for batteries is adopted and four operating modes are analyzed as charging-positive, charging-negative, discharging-positive and discharging-negative modes. An additional mechanism for fast charging or fast discharging is also designed to secure normal operation...... of batteries. With the proposed DCES, the power fluctuations due to intermittent RESs can be passed to non-critical loads (NCLs) and batteries while power on critical loads (CLs) is kept stable. This is possibly the first attempt to design a DCES with only DC/DC converters. The performances of the proposed...
Directory of Open Access Journals (Sweden)
Muhamad Zalani Daud
2014-01-01
Full Text Available This paper presents an evaluation of an optimal DC bus voltage regulation strategy for grid-connected photovoltaic (PV system with battery energy storage (BES. The BES is connected to the PV system DC bus using a DC/DC buck-boost converter. The converter facilitates the BES power charge/discharge to compensate for the DC bus voltage deviation during severe disturbance conditions. In this way, the regulation of DC bus voltage of the PV/BES system can be enhanced as compared to the conventional regulation that is solely based on the voltage-sourced converter (VSC. For the grid side VSC (G-VSC, two control methods, namely, the voltage-mode and current-mode controls, are applied. For control parameter optimization, the simplex optimization technique is applied for the G-VSC voltage- and current-mode controls, including the BES DC/DC buck-boost converter controllers. A new set of optimized parameters are obtained for each of the power converters for comparison purposes. The PSCAD/EMTDC-based simulation case studies are presented to evaluate the performance of the proposed optimized control scheme in comparison to the conventional methods.
Daud, Muhamad Zalani; Mohamed, Azah; Hannan, M A
2014-01-01
This paper presents an evaluation of an optimal DC bus voltage regulation strategy for grid-connected photovoltaic (PV) system with battery energy storage (BES). The BES is connected to the PV system DC bus using a DC/DC buck-boost converter. The converter facilitates the BES power charge/discharge to compensate for the DC bus voltage deviation during severe disturbance conditions. In this way, the regulation of DC bus voltage of the PV/BES system can be enhanced as compared to the conventional regulation that is solely based on the voltage-sourced converter (VSC). For the grid side VSC (G-VSC), two control methods, namely, the voltage-mode and current-mode controls, are applied. For control parameter optimization, the simplex optimization technique is applied for the G-VSC voltage- and current-mode controls, including the BES DC/DC buck-boost converter controllers. A new set of optimized parameters are obtained for each of the power converters for comparison purposes. The PSCAD/EMTDC-based simulation case studies are presented to evaluate the performance of the proposed optimized control scheme in comparison to the conventional methods.
Cohen, Ayala; Nahum-Shani, Inbal; Doveh, Etti
2010-01-01
In their seminal paper, Edwards and Parry (1993) presented the polynomial regression as a better alternative to applying difference score in the study of congruence. Although this method is increasingly applied in congruence research, its complexity relative to other methods for assessing congruence (e.g., difference score methods) was one of the…
The GMD Method for Inductance Calculation Applied to Conductors with Skin Effect
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H. A. Aebischer
2017-09-01
Full Text Available The GMD method (geometric mean distance to calculate inductance offers undoubted advantages over other methods. But so far it seemed to be limited to the case where the current is uniformly distributed over the cross section of the conductor, i.e. to DC (direct current. In this paper, the definition of the GMD is extended to include cases of nonuniform distribution observed at higher frequencies as the result of skin effect. An exact relation between the GMD and the internal inductance per unit length for infinitely long conductors of circularly symmetric cross section is derived. It enables much simpler derivations of Maxwell’s analytical expressions for the GMD of circular and annular disks than were known before. Its salient application, however, is the derivation of exact expressions for the GMD of infinitely long round wires and tubular conductors with skin effect. These expressions are then used to verify the consistency of the extended definition of the GMD. Further, approximate formulae for the GMD of round wires with skin effect based on elementary functions are discussed. Total inductances calculated with the help of the derived formulae for the GMD with and without skin effect are compared to measurement results from the literature. For conductors of square cross section, an analytical approximation for the GMD with skin effect based on elementary functions is presented. It is shown that it allows to calculate the total inductance of such conductors for frequencies from DC up to 25 GHz to a precision of better than 1 %.
Five-Level Active-Neutral-Point-Clamped DC/DC Converter for Medium-Voltage DC Grids
DEFF Research Database (Denmark)
Liu, Dong; Deng, Fujin; Chen, Zhe
2017-01-01
/dt, reduce voltage stress on the transformer, and thus reduce the electromagnetic interference (EMI) and increase reliability. An elimination method for the dead time effect is also proposed along with the proposed modulation strategy by employing a switch in series with the flying capacitor, which can......This paper proposes a five-level active-neutralpoint- clamped (5L-ANPC) dc/dc converter for applications in medium voltage dc (MVDC) grids. A modulation strategy is proposed for the 5L-ANPC dc/dc converter to generate multilevel voltage waveforms, which can effectively reduce voltage change rate dv...
An Integrated Programmable Wide-range PLL for Switching Synchronization in Isolated DC-DC Converters
Fard, Miad
In this thesis, two Phase-Locked-Loop (PLL) based synchronization schemes are introduced and applied to a bi-directional Dual-Active-Bridge (DAB) dc-dc converter with an input voltage up to 80 V switching in the range of 250 kHz to 1 MHz. The two schemes synchronize gating signals across an isolated boundary without the need for an isolator per transistor. The Power Transformer Sensing (PTS) method utilizes the DAB power transformer to indirectly sense switching on the secondary side of the boundary, while the Digital Isolator Sensing (DIS) method utilizes a miniature transformer for synchronization and communication at up to 100 MHz. The PLL is implemented on-chip, and is used to control an external DAB power-stage. This work will lead to lower cost, high-frequency isolated dc-dc converters needed for a wide variety of emerging low power applications where isolator cost is relatively high and there is a demand for the reduction of parts.
Yoo, Seung-Wan; Hwang, Nong-Moon; You, Shin-Jae; Kim, Jung-Hyung; Seong, Dae-Jin
2017-11-01
The effect of applying a bias to the substrate on the size and amount of charged crystalline silicon nanoparticles deposited on the substrate was investigated in the inductively coupled plasma chemical vapor deposition process. By inserting the grounded grid with meshes above the substrate, the region just above the substrate was separated from the plasma. Thereby, crystalline Si nanoparticles formed by the gas-phase reaction in the plasma could be deposited directly on the substrate, successfully avoiding the formation of a film. Moreover, the size and the amount of deposited nanoparticles could be changed by applying direct current bias to the substrate. When the grid of 1 × 1-mm-sized mesh was used, the nanoparticle flux was increased as the negative substrate bias increased from 0 to - 50 V. On the other hand, when a positive bias was applied to the substrate, Si nanoparticles were not deposited at all. Regardless of substrate bias voltages, the most frequently observed nanoparticles synthesized with the grid of 1 × 1-mm-sized mesh had the size range of 10-12 nm in common. When the square mesh grid of 2-mm size was used, as the substrate bias was increased from - 50 to 50 V, the size of the nanoparticles observed most frequently increased from the range of 8-10 to 40-45 nm but the amount that was deposited on the substrate decreased.
Decentralized Interleaving of Paralleled Dc-Dc Buck Converters: Preprint
Energy Technology Data Exchange (ETDEWEB)
Johnson, Brian B [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rodriguez, Miguel [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sinha, Mohit [University of Minnesota; Dhople, Sairaj [University of Minnesota; Poon, Jason [University of California at Berkeley
2017-09-01
We present a decentralized control strategy that yields switch interleaving among parallel connected dc-dc buck converters without communication. The proposed method is based on the digital implementation of the dynamics of a nonlinear oscillator circuit as the controller. Each controller is fully decentralized, i.e., it only requires the locally measured output current to synthesize the pulse width modulation (PWM) carrier waveform. By virtue of the intrinsic electrical coupling between converters, the nonlinear oscillator-based controllers converge to an interleaved state with uniform phase-spacing across PWM carriers. To the knowledge of the authors, this work represents the first fully decentralized strategy for switch interleaving of paralleled dc-dc buck converters.
Method and device for ion mobility separations
Ibrahim, Yehia M.; Garimella, Sandilya V. B.; Smith, Richard D.
2017-07-11
Methods and devices for ion separations or manipulations in gas phase are disclosed. The device includes a single non-planar surface. Arrays of electrodes are coupled to the surface. A combination of RF and DC voltages are applied to the arrays of electrodes to create confining and driving fields that move ions through the device. The DC voltages are static DC voltages or time-dependent DC potentials or waveforms.
Directory of Open Access Journals (Sweden)
Haojie Wang
2016-07-01
Full Text Available It is a common practice for storage batteries to be connected to DC microgrid buses through DC-DC converters for voltage support on islanded operation mode. A feed-forward control based dual-loop constant voltage PI control for three-branch interleaved DC-DC converters (TIDC is proposed for storage batteries in DC microgrids. The working principle of TIDC is analyzed, and the factors influencing the response rate based on the dual-loop constant voltage control for TIDC are discussed, and then the method of feed-forward control for TIDC is studied to improve the response rate for load changing. A prototype of the TIDC is developed and an experimental platform is built. The experiment results show that DC bus voltage sags or swells caused by load changing can be reduced and the time for voltage recovery can be decreased significantly with the proposed feed-forward control.
Reshetenko, Tatyana; Odgaard, Madeleine; Schlueter, Debbie; Serov, Alexey
2018-01-01
Membrane electrode assemblies (MEAs) for anion exchange membrane fuel cells (AEMFCs) were manufactured from commercial materials: Pt/C catalyst, A201 AEM and AS4 ionomer by using an industrial mass-production digital printing method. The MEA designs selected are close to those recommended by US Department of Energy, including low loading of platinum on the cathode side (0.2 mg cm-2). Polarization curves and electrochemical impedance spectroscopy (EIS) were applied for MEA evaluation in fuel cell conditions with variation of gas humidification and oxygen partial pressure (air vs oxygen). The typical impedance curves recorded at H2/O2 gas configuration consist of high- and medium-frequency arcs responsible for hydrogen oxidation and oxygen reduction, respectively. Operation with air as a cathode feed gas resulted in a decrease in AEMFC performance due to possible CO2 poisoning and mass transfer losses. At the same time, EIS demonstrated formation of a low frequency loop due to diffusion limitations. Despite the low loading of platinum on the cathode (0.2 mg cm-2), a peak power density of ∼330 mW cm-2 was achieved (at 50/50% of RH on anode and cathode), which is substantially higher performance than for AEMFC MEAs tested at similar conditions.
DEFF Research Database (Denmark)
Zhang, Chunjiang; Zhao, Xiaojun; Wang, Xiaohuan
2018-01-01
. A detailed theoretical analysis on the proposed MSTOGI is presented to reveal the mechanism of eliminating the dc offset. After that, the MSTOGI is applied to a phase-locked loop (PLL) and thereby establish an MSTOGI-PLL which is more adaptable to various grid conditions and power quality. Moreover......, a frequency-adaptive control scheme is added to the proposed MSTOGI-PLL to eliminate the phase difference between the PLL output and the grid in grid-connected applications where the grid frequency may vary. Finally, the experimental results from a laboratory prototype are given to demonstrate and verify...... the effectiveness of the proposed MSTOGI-PLL in terms of steady-state performance, dynamic response and frequency adaptability....
Yuval, Douglas; Oldenburg, W.
1996-04-01
Oxidation of sulfide minerals in the mine tailings impoundments at Copper Cliff, Ontario generates acidic conditions and elevated concentrations of dissolved metals and sulfates in the pore water. The pore water migrates away from the tailings to pose a potential environmental hazard if is should reach nearby water systems. There is a need to characterize this potential environmental problem and to assess the future hazards. A combined DC resistivity and induced polarization (IP) survey was carried out along one of the major flowpaths in the tailings and the data were inverted to produce detailed electrical conductivity and chargeability structures of the cross-section below the survey line. The conductivity distributions are directly translated, through theoretical and empirical relations, to a map of the concentration of the total dissolved solids (TDS) along the cross-section and thereby provide insight about the in-situ pore water quality. The sulfide minerals are the source of the IP response and, thus, when combined with borehole data, the chargeability model can be used to estimate the amount and distribution of the sulfides.
Fuzzy Logic Controlled DC-DC Converter Based Dynamic Voltage Restorer
Directory of Open Access Journals (Sweden)
Mustafa İnci
2015-12-01
Full Text Available This paper presents fuzzy logic controlled dc-dc boost converter based Dynamic Voltage Restorer (DVR to compensate severe voltage sag problems in an electrical system. DVR absorbs real power from battery to compensate voltage sags in the system. This condition causes reduction in voltage magnitude of dc-link capacitor. Additionally, DVR requires large dc capacitors to compensate long and severe voltage sags in the system. In this study, dc-dc boost converter is connected to DVR for keeping dc link voltage constant. For this propose, a control algorithm based on Fuzzy Logic (FL control is developed for dc-dc boost converter. The main contribution of this study is that Fuzzy Logic (FL is firstly used to generate reference signal for PWM signals of dc-dc converter applied in DVR. FL is a very flexible controller which keeps the dc link voltage constant during voltage sag. The performance results of proposed study are verified with PSCAD/EMDTC.
Extra-High-Voltage DC-DC Boost Converters Topology with Simple Control Strategy
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P. Sanjeevikumar
2008-01-01
Full Text Available This paper presents the topology of operating DC-DC buck converter in boost mode for extra-high-voltage applications. Traditional DC-DC boost converters are used in high-voltage applications, but they are not economical due to the limited output voltage, efficiency and they require two sensors with complex control algorithm. Moreover, due to the effect of parasitic elements the output voltage and power transfer efficiency of DC-DC converters are limited. These limitations are overcome by using the voltage lift technique, opens a good way to improve the performance characteristics of DC-DC converter. The technique is applied to DC-DC converter and a simplified control algorithm in this paper. The performance of the controller is studied for both line and load disturbances. These converters perform positive DC-DC voltage increasing conversion with high power density, high efficiency, low cost in simple structure, small ripples, and wide range of control. Simulation results along theoretical analysis are provided to verify its performance.
Accurate Simulation of MPPT Methods Performance When Applied to Commercial Photovoltaic Panels
Cubas, Javier; Pindado, Santiago; Sanz-Andrés, Ángel
2015-01-01
A new, simple, and quick-calculation methodology to obtain a solar panel model, based on the manufacturers' datasheet, to perform MPPT simulations, is described. The method takes into account variations on the ambient conditions (sun irradiation and solar cells temperature) and allows fast MPPT methods comparison or their performance prediction when applied to a particular solar panel. The feasibility of the described methodology is checked with four different MPPT methods applied to a commer...
Directory of Open Access Journals (Sweden)
Bangcheng Han
2013-01-01
Full Text Available We firstly report on an investigation into the unbalanced magnetic pull (UMP effect on the static stiffness models of radial active magnetic bearing (RAMB in brushless DC motor (BDCM in no-loaded and loaded conditions using the finite element method (FEM. The influences of the UMP on the force-control current, force-position, current stiffness, and position stiffness of RAMB are clarified in BDCM with 100 kW rated power. We found the position stiffness to be more susceptible to UMP. The primary source of UMP is the permanent magnets of BDCM. In addition, the performance of RAMB is affected by the UMP ripples during motor commutation and also periodically affected by the angular position of rotor. The characteristic curves of RAMB force versus control current (or rotor position and angular position of rotor affected by the UMP are given. The method is useful in design and optimization of RAMB in magnetically suspended BDCMs.
DEFF Research Database (Denmark)
Gao, Congzhe; Jiang, Xinjian; Li, Yongdong
2013-01-01
Voltage balance issue of dc-link capacitors is very important for applications of a cascade multilevel converter or a modular multilevel converter. In this paper, a novel diode-clamped modular multilevel converter (DCM2C) topology is proposed and a power feedback control method is developed....... With the developed control strategy, the proposed diode-clamped circuit becomes a controllable closed loop which enables the capacitor voltages to be clamped by low power rating clamping diodes. The proposed topology and control strategy has quicker response and requires much fewer voltage sensors than the normally...... used traditional method; therefore, the system performance improvement and cost reduction are expected. Based on the proposed DCM2C, a novel N +1-level cascade multilevel topology is proposed for a cascade active power filter (CS-APF). The simulation and experimental results from the CS-APF have...
Foundations of DC plasma sources
Tomas Gudmundsson, Jon; Hecimovic, Ante
2017-12-01
A typical dc discharge is configured with the negative cathode at one end and a positive anode at the other end, separated by a gas filled gap, placed inside a long glass cylinder. A few hundred volts between the cathode and anode is required to maintain the discharge. The type of discharge that is formed between the two electrodes depends upon the pressure of the working gas, the nature of the working gas, the applied voltage and the geometry of the discharge. We discuss the current–voltage characteristics of the discharge as well as the distinct structure that develops in the glow discharge region. The dc glow discharge appears in the discharge current range from μA to mA at 0.5–300 Pa pressure. We discuss the various phenomena observed in the dc glow discharge, including the cathode region, the positive column, and striations. The dc glow discharge is maintained by the emission of secondary electrons from the cathode target due to the bombardment of ions. For decades, the dc glow discharge has been used as a sputter source. Then it is often operated as an obstructed abnormal glow discharge and the required applied voltage is in the range 2–5 kV. Typically, the cathode target (the material to be deposited) is connected to a negative voltage supply (dc or rf) and the substrate holder faces the target. The relatively high operating pressure, in the range from 2 to 4 Pa, high applied voltages, and the necessity to have a conductive target limit the application of dc glow discharge as a sputter source. In order to lower the discharge voltage and expand the operation pressure range, the lifetime of the electrons in target vicinity is increased through applying magnetic field, by adding permanent magnets behind the cathode target. This arrangement is coined the magnetron sputtering discharge. The various configurations of the magnetron sputtering discharge and its applications are described. Furthermore, the use of dc discharges for chemical analysis, the
The application of standardized control and interface circuits to three dc to dc power converters.
Yu, Y.; Biess, J. J.; Schoenfeld, A. D.; Lalli, V. R.
1973-01-01
Standardized control and interface circuits were applied to the three most commonly used dc to dc converters: the buck-boost converter, the series-switching buck regulator, and the pulse-modulated parallel inverter. The two-loop ASDTIC regulation control concept was implemented by using a common analog control signal processor and a novel digital control signal processor. This resulted in control circuit standardization and superior static and dynamic performance of the three dc-to-dc converters. Power components stress control, through active peak current limiting and recovery of switching losses, was applied to enhance reliability and converter efficiency.
Koskey, Kristin L. K.; Sondergeld, Toni A.; Stewart, Victoria C.; Pugh, Kevin J.
2018-01-01
Onwuegbuzie and colleagues proposed the Instrument Development and Construct Validation (IDCV) process as a mixed methods framework for creating and validating measures. Examples applying IDCV are lacking. We provide an illustrative case integrating the Rasch model and cognitive interviews applied to the development of the Transformative…
An Aural Learning Project: Assimilating Jazz Education Methods for Traditional Applied Pedagogy
Gamso, Nancy M.
2011-01-01
The Aural Learning Project (ALP) was developed to incorporate jazz method components into the author's classical practice and her applied woodwind lesson curriculum. The primary objective was to place a more focused pedagogical emphasis on listening and hearing than is traditionally used in the classical applied curriculum. The components of the…
Simultaneous distribution of AC and DC power
Polese, Luigi Gentile
2015-09-15
A system and method for the transport and distribution of both AC (alternating current) power and DC (direct current) power over wiring infrastructure normally used for distributing AC power only, for example, residential and/or commercial buildings' electrical wires is disclosed and taught. The system and method permits the combining of AC and DC power sources and the simultaneous distribution of the resulting power over the same wiring. At the utilization site a complementary device permits the separation of the DC power from the AC power and their reconstruction, for use in conventional AC-only and DC-only devices.
SMALL-SIGNAL ANALYZING OF SEPARATELY EXCITED DC MOTOR FED DC - DC CHOPPER
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İSMAİL COŞKUN
1999-12-01
Full Text Available Choppers are widely used in order to get smooth speed characteristics of DC motors. If the load or input voltage is changed, a feedback control technique is used to get the constant speed. To design the proper feedback control, the transfer function of the chopper-motor combination should be kno\\vn. ln this study, the effort was given to obtain the general black diagram, inciurling the field current and aı1na ture current of chopper-fed DC motor. It can be seen from the black diagram that the chopper circuit modifies the transfer function of the DC motor. DC-DC DARBEL E YİCİ iLE YABANCI UYARTIMLI DC KÜÇÜK SİNY AL ANALİZİ ÖZET BESLENEN MOT O RUN DC motorlardan düzgün bir hız karakteristiği elde etmek için darbeleyiciler çok kullamlır. Eğer yük ya da giriş gerilimi de ği şirse, sabit hız elde etmek için geribeslemeli kontrol tekniği kuJlanılır. Uygun bir geribesleme kontrolu tasarlamak iç� darbeliyici-motor kombinasy onunun transfer fonksiyonu bilinmelidir. -Bu çalışma da, darbeleyici ile beslenen DC motorun alan akımı ve endüvi akımını da kapsayan genel blok diyağraınını elde etıııek için çaba gösterilmiştir. Blok diyagramından görülebilec eği gibi, darbeleyici devresi DC motorun tra nsfer fonksiyonunu değiştirmektedir. I. INTRODUCTI ON Choppers are widely used for speed control of DC separately excited motors as they offer high efficiency, quick response, wide speed control range and regeneration down to very low speeds [ 1] . All chopper circuits can be classified into two groups. (a Load ind ependent choppers� in which the output voltage waveform is either a square wave or can be approximated by a square \\vave. (b Load dependent choppers, in which charging of the commutating capacitor is govemed by load current. In such cases, the output voltage wavefoım is neither a square wave nor can be approximated by a square wave. Various methods of analyzing of DC motors fed by a chopper with
DEFF Research Database (Denmark)
Wei, Baoze; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez
2016-01-01
This paper describes a theoretical with experiment study on a control strategy for the parallel operation of threephase voltage source inverters (VSI), to be applied to uninterruptible power systems (UPS). A circulating current suppression strategy for parallel VSIs is proposed in this paper based...
Wielandt method applied to the diffusion equations discretized by finite element nodal methods
International Nuclear Information System (INIS)
Mugica R, A.; Valle G, E. del
2003-01-01
Nowadays the numerical methods of solution to the diffusion equation by means of algorithms and computer programs result so extensive due to the great number of routines and calculations that should carry out, this rebounds directly in the execution times of this programs, being obtained results in relatively long times. This work shows the application of an acceleration method of the convergence of the classic method of those powers that it reduces notably the number of necessary iterations for to obtain reliable results, what means that the compute times they see reduced in great measure. This method is known in the literature like Wielandt method and it has incorporated to a computer program that is based on the discretization of the neutron diffusion equations in plate geometry and stationary state by polynomial nodal methods. In this work the neutron diffusion equations are described for several energy groups and their discretization by means of those called physical nodal methods, being illustrated in particular the quadratic case. It is described a model problem widely described in the literature which is solved for the physical nodal grade schemes 1, 2, 3 and 4 in three different ways: to) with the classic method of the powers, b) method of the powers with the Wielandt acceleration and c) method of the powers with the Wielandt modified acceleration. The results for the model problem as well as for two additional problems known as benchmark problems are reported. Such acceleration method can also be implemented to problems of different geometry to the proposal in this work, besides being possible to extend their application to problems in 2 or 3 dimensions. (Author)
What is the method in applying formal methods to PLC applications?
Mader, Angelika H.; Engel, S.; Wupper, Hanno; Kowalewski, S.; Zaytoon, J.
2000-01-01
The question we investigate is how to obtain PLC applications with confidence in their proper functioning. Especially, we are interested in the contribution that formal methods can provide for their development. Our maxim is that the place of a particular formal method in the total picture of system
DEFF Research Database (Denmark)
Haxthausen, Anne Elisabeth; Yong, X.
2000-01-01
Duration Calculus (DC) is an interval-based real-time logic, which can be used in capturing and eliciting users' real-time requirements. The Timed RAISE Specification Language (TRSL) is an extension of the RAISE Specification Language with real-time features. This paper links DC and TRSL together...... in a method for real-time developments. An operational semantics with behavior is specified for TRSL. It is defined what its means for a TRSL process to satisfy a DC requirement, and a method for verifying whether the satisfaction relation holds or not is provided. Our contribution also demonstrates a general...... approach for linking state-based real-time logics together with event-based, timed process algebra languages....
Formal methods applied to industrial complex systems implementation of the B method
Boulanger, Jean-Louis
2014-01-01
This book presents real-world examples of formal techniques in an industrial context. It covers formal methods such as SCADE and/or the B Method, in various fields such as railways, aeronautics, and the automotive industry. The purpose of this book is to present a summary of experience on the use of "formal methods" (based on formal techniques such as proof, abstract interpretation and model-checking) in industrial examples of complex systems, based on the experience of people currently involved in the creation and assessment of safety critical system software. The involvement of people from
Charge pump DC-DC converter comprising solid state batteries
Reefman, D.; Roozeboom, F.; Notten, P.H.L.; Klootwijk, J.H.
2013-01-01
An electronic device is provided which comprises a DC-DC converter. The DC-DC converter comprises at least one solid-state rechargeable battery (B1, B2) for storing energy for the DC-DC conversion and an output capacitor (C2).
Campbell, Jeremy B; Newson, Steve
2013-02-26
Embodiments of DC source assemblies of power inverter systems of the type suitable for deployment in a vehicle having an electrically grounded chassis are provided. An embodiment of a DC source assembly comprises a housing, a DC source disposed within the housing, a first terminal, and a second terminal. The DC source also comprises a first capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the first terminal. The DC source assembly further comprises a second capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the second terminal.
The Wigner method applied to the photodissociation of CH3I
DEFF Research Database (Denmark)
Henriksen, Niels Engholm
1985-01-01
The Wigner method is applied to the Shapiro-Bersohn model of the photodissociation of CH3I. The partial cross sections obtained by this semiclassical method are in very good agreement with results of exact quantum calculations. It is also shown that a harmonic approximation to the vibrational...
A new clamp method for firing bricks | Obeng | Journal of Applied ...
African Journals Online (AJOL)
A new clamp method for firing bricks. ... Journal of Applied Science and Technology ... To overcome this operational deficiencies, a new method of firing bricks that uses brick clamp technique that incorporates a clamp wall of 60 cm thickness, a six tier approach of sealing the top of the clamp (by combination of green bricks) ...
Determination methods for plutonium as applied in the field of reprocessing
International Nuclear Information System (INIS)
1983-07-01
The papers presented report on Pu-determination methods, which are routinely applied in process control, and also on new developments which could supercede current methods either because they are more accurate or because they are simpler and faster. (orig./DG) [de
1978-10-01
This report presents a method that may be used to evaluate the reliability of performance of individual subjects, particularly in applied laboratory research. The method is based on analysis of variance of a tasks-by-subjects data matrix, with all sc...
Water Permeability of Pervious Concrete Is Dependent on the Applied Pressure and Testing Methods
Directory of Open Access Journals (Sweden)
Yinghong Qin
2015-01-01
Full Text Available Falling head method (FHM and constant head method (CHM are, respectively, used to test the water permeability of permeable concrete, using different water heads on the testing samples. The results indicate the apparent permeability of pervious concrete decreasing with the applied water head. The results also demonstrate the permeability measured from the FHM is lower than that from the CHM. The fundamental difference between the CHM and FHM is examined from the theory of fluid flowing through porous media. The testing results suggest that the water permeability of permeable concrete should be reported with the applied pressure and the associated testing method.
Accurate Simulation of MPPT Methods Performance When Applied to Commercial Photovoltaic Panels
Directory of Open Access Journals (Sweden)
Javier Cubas
2015-01-01
Full Text Available A new, simple, and quick-calculation methodology to obtain a solar panel model, based on the manufacturers’ datasheet, to perform MPPT simulations, is described. The method takes into account variations on the ambient conditions (sun irradiation and solar cells temperature and allows fast MPPT methods comparison or their performance prediction when applied to a particular solar panel. The feasibility of the described methodology is checked with four different MPPT methods applied to a commercial solar panel, within a day, and under realistic ambient conditions.
Accurate simulation of MPPT methods performance when applied to commercial photovoltaic panels.
Cubas, Javier; Pindado, Santiago; Sanz-Andrés, Ángel
2015-01-01
A new, simple, and quick-calculation methodology to obtain a solar panel model, based on the manufacturers' datasheet, to perform MPPT simulations, is described. The method takes into account variations on the ambient conditions (sun irradiation and solar cells temperature) and allows fast MPPT methods comparison or their performance prediction when applied to a particular solar panel. The feasibility of the described methodology is checked with four different MPPT methods applied to a commercial solar panel, within a day, and under realistic ambient conditions.
Energy Technology Data Exchange (ETDEWEB)
Nurmukhanbetova, A.K. [National Laboratory Astana, Nazarbayev University, Astana 010000 (Kazakhstan); Goldberg, V.Z. [Cyclotron Institute, Texas A& M University, College Station, TX (United States); Nauruzbayev, D.K. [National Laboratory Astana, Nazarbayev University, Astana 010000 (Kazakhstan); Saint Petersburg State University, Saint Petersburg (Russian Federation); Rogachev, G.V. [Cyclotron Institute, Texas A& M University, College Station, TX (United States); Golovkov, M.S. [Joint Institute of Nuclear Research, Dubna (Russian Federation); Dubna State University, Dubna (Russian Federation); Mynbayev, N.A. [National Laboratory Astana, Nazarbayev University, Astana 010000 (Kazakhstan); Artemov, S.; Karakhodjaev, A. [Institute of Nuclear Physics, Tashkent (Uzbekistan); Kuterbekov, K. [L.N. Gumilov Eurasian National University, Astana (Kazakhstan); Rakhymzhanov, A. [National Laboratory Astana, Nazarbayev University, Astana 010000 (Kazakhstan); Berdibek, Zh. [School of Science and Technology, Nazarbayev University, Astana (Kazakhstan); Ivanov, I. [Institute of Nuclear Physics, Astana (Kazakhstan); Tikhonov, A. [School of Science and Technology, Nazarbayev University, Astana (Kazakhstan); Zherebchevsky, V.I.; Torilov, S. Yu. [Saint Petersburg State University, Saint Petersburg (Russian Federation); Tribble, R.E. [Cyclotron Institute, Texas A& M University, College Station, TX (United States)
2017-03-01
To study resonance reactions of heavy ions at low energy we have combined the Thick Target Inverse Kinematics Method (TTIK) with Time of Flight method (TF). We used extended target and TF to resolve the identification problems of various possible nuclear processes inherent to the simplest popular version of TTIK. Investigations of the {sup 15}N interaction with hydrogen and helium gas targets by using this new approach are presented.
Fukushima, Toshio
2004-12-01
We apply our single scaling method to the numerical integration of perturbed two-body problems regularized by the Kustaanheimo-Stiefel (K-S) transformation. The scaling is done by multiplying a single scaling factor with the four-dimensional position and velocity vectors of an associated harmonic oscillator in order to maintain the Kepler energy relation in terms of the K-S variables. As with the so-called energy rectification of Aarseth, the extra cost for the scaling is negligible, since the integration of the Kepler energy itself is already incorporated in the original K-S formulation. On the other hand, the single scaling method can be applied at every integration step without facing numerical instabilities. For unperturbed cases, the single scaling applied at every step gives a better result than either the original K-S formulation, the energy rectification applied at every apocenter, or the single scaling method applied at every apocenter. For the perturbed cases, however, the single scaling method applied at every apocenter provides the best performance for all perturbation types, whether the main source of error is truncation or round-off.
Design and Simulation of PID parameters self-tuning based on DC speed regulating system
Directory of Open Access Journals (Sweden)
Feng Wei Jie
2016-01-01
Full Text Available The DC speed regulating system has many difficult issues such as system parameters and PID control parameters are difficult to determine. On the basis of model for a single closed-loop DC speed regulating system, this paper puts forward a method of PID parameters self-tuning based on the step response detection and reduced order equivalent. First, detect system step response and get response parameters. Then equal it to a second order system model, and achieve optimal PID control parameters based on optimal second order system to realize of PID parameters self-tuning. The PID parameters self-tuning process of DC speed regulating system is simulated with the help of MATLAB/Simulink. The simulation results show that the method is simple and effective. The system can obtain good dynamic and static performance when the PID parameters are applied to DC speed regulating system.
Active Problem Solving and Applied Research Methods in a Graduate Course on Numerical Methods
Maase, Eric L.; High, Karen A.
2008-01-01
"Chemical Engineering Modeling" is a first-semester graduate course traditionally taught in a lecture format at Oklahoma State University. The course as taught by the author for the past seven years focuses on numerical and mathematical methods as necessary skills for incoming graduate students. Recent changes to the course have included Visual…
Viewpoint: An Alternative Teaching Method. The WFTU Applies Active Methods to Educate Workers.
Courbe, Jean-Francois
1989-01-01
Develops a set of ideas and practices acquired from experience in organizing trade union education sessions. The method is based on observations that lecturing has not proved highly efficient, although traditional approaches--lecture, reading, discussion--are not totally rejected. (JOW)
Ando, Yoshinobu; Eguchi, Yuya; Mizukawa, Makoto
In this research, we proposed and evaluated a management method of college mechatronics education. We applied the project management to college mechatronics education. We practiced our management method to the seminar “Microcomputer Seminar” for 3rd grade students who belong to Department of Electrical Engineering, Shibaura Institute of Technology. We succeeded in management of Microcomputer Seminar in 2006. We obtained the good evaluation for our management method by means of questionnaire.
Romão, Wanderson; Schwab, Nicolas V; Bueno, Maria Izabel M. S; Sparrapan, Regina; Eberlin, Marcos N; Martiny, Andrea; Sabino, Bruno D; Maldaner, Adriano O
2011-01-01
In this review recent methods developed and applied to solve criminal occurences related to documentoscopy, ballistic and drugs of abuse are discussed. In documentoscopy, aging of ink writings, the sequence of line crossings and counterfeiting of documents are aspects to be solved with reproducible, fast and non-destructive methods. In ballistic, the industries are currently producing ''lead-free'' or ''nontoxic'' handgun ammunitions, so new methods of gunshot residues characterization are be...
Effects of resistive bodies on DC electrical soundings
Directory of Open Access Journals (Sweden)
L. Alfano
1996-06-01
Full Text Available Some deep DC electrical soundings, performed in alpine and apenninic areas with the continuous polar dipole-dipole spread, show apparent resistivity curves with positive slopes. Measured values of apparent resistivity reach 30000 Wm. Applying the "surface charges" method we developed three dimensional mathematical models, by means of which we can state simple rules for determining the minimum extensions of the deep resistive bodies, fundamental information for a more precise interpretation of the field results.
Apparatus and method for applying an end plug to a fuel rod tube end
International Nuclear Information System (INIS)
Rieben, S.L.; Wylie, M.E.
1987-01-01
An apparatus is described for applying an end plug to a hollow end of a nuclear fuel rod tube, comprising: support means mounted for reciprocal movement between remote and adjacent positions relative to a nuclear fuel rod tube end to which an end plug is to be applied; guide means supported on the support means for movement; and drive means coupled to the support means and being actuatable for movement between retracted and extended positions for reciprocally moving the support means between its respective remote and adjacent positions. A method for applying an end plug to a hollow end of a nuclear fuel rod tube is also described
Method of levelized discounted costs applied in economic evaluation of nuclear power plant project
International Nuclear Information System (INIS)
Tian Li; Wang Yongqing; Liu Jingquan; Guo Jilin; Liu Wei
2000-01-01
The main methods of economic evaluation of bid which are in common use are introduced. The characteristics of levelized discounted cost method and its application are presented. The method of levelized discounted cost is applied to the cost calculation of a 200 MW nuclear heating reactor economic evaluation. The results indicate that the method of levelized discounted costs is simple, feasible and which is considered most suitable for the economic evaluation of various case. The method is suggested which is used in the national economic evaluation
International Nuclear Information System (INIS)
Erdogan, E.
2007-01-01
In earth investigation done by using the direct current resistivity technique, impact of the change in the examined surface topography on determining the resistivity distrubition in the earth has been a frequently faced question. In order to get more fruitful results and make more correct interpretetions in earth surveying carried on the areas where topographical changes occur, modelling should be done by taking the change in surface topography into account and topography effect should be included into inversion. In this study impact of topography to the direct current resistivity method has been analysed. For this purpose, 2-D forward modeling algorithm has been developed by using finite element method. In this algorithm impact of topography can be incorporate into the model. Also the pseudo sections which is produced from the program can be imaged with topography. By using this algorithm response of models under different surface topography has been analysed and compared with the straight topography of same models
Method to detect substances in a body and device to apply the method
International Nuclear Information System (INIS)
Voigt, H.
1978-01-01
The method and the measuring disposition serve to localize pellets doped with Gd 2 O 3 , lying between UO 2 pellets within a reactor fuel rod. The fuel rod is penetrating a homogeneous magnetic field generated between two pole shoes. The magnetic stray field caused by the doping substances is then measured by means of Hall probes (e.g. InAs) for quantitative discrimination from UO 2 . The position of the Gd 2 O 3 -doped pellets is determined by moving the fuel rod through the magnetic field in a direction perpendicular to the homogeneous field. The measuring signal is caused by the different susceptibility of Gd 2 O 3 with respect to UO 2 . (DG) [de
DEFF Research Database (Denmark)
Qin, Zian; Wang, Huai; Blaabjerg, Frede
2014-01-01
.g. ambient temperature, humidity, etc.) and operating stresses (e.g. voltage, ripple current). This paper serves to investigate the ways of reducing ripple current stresses of DC-link capacitors in back-toback converters. The outcome could benefit to achieve either an extended lifetime for a designed DC......Three-phase back-to-back converters have a wide range of applications (e.g. wind turbines) in which the reliability and cost-effectiveness are of great concern. Among other components and interconnections, DC-link capacitors are one of the weak links influenced by environmental stresses (e...
Directory of Open Access Journals (Sweden)
Despoina I. Makrygiorgou
2017-03-01
Full Text Available Direct current (DC distribution systems and DC microgrids are becoming a reliable and efficient alternative energy system, compatible with the DC nature of most of the distributed energy resources (DERs, storage devices and loads. The challenging problem of redesigning an autonomous DC-grid system in view of using energy storage devices to balance the power produced and absorbed, by applying simple decentralized controllers on the electronic power interfaces, is investigated in this paper. To this end, a complete nonlinear DC-grid model has been deployed that includes different DC-DERs, two controlled parallel battery branches, and different varying DC loads. Since many loads in modern distribution systems are connected through power converters, both constant power loads and simple resistive loads are considered in parallel. Within this system, suitable cascaded controllers on the DC/DC power converter interfaces to the battery branches are proposed, in a manner that ensures stability and charge sharing between the two branches at the desired ratio. To achieve this task, inner-loop current controllers are combined with outer-loop voltage, droop-based controllers. The proportional-integral (PI inner-loop current controllers include damping terms and are fully independent from the system parameters. The controller scheme is incorporated into the system model and a globally valid nonlinear stability analysis is conducted; this differs from small-signal linear methods that are valid only for specific systems, usually via eigenvalue investigations. In the present study, under the virtual cost of applying advanced Lyapunov techniques on the entire nonlinear system, a rigorous analysis is formulated to prove stability and convergence to the desired operation, regardless of the particular system characteristics. The theoretical results are evaluated by detailed simulations, with the system performance being very satisfactory.
Directory of Open Access Journals (Sweden)
Tao Lin
2018-01-01
Full Text Available Accurate detection and effective control strategy of commutation failure (CF of high voltage direct current (HVDC are of great significance for keeping the safe and stable operations of the hybrid power grid. At first, a novel detection method for consecutive CF is proposed. Concretely, the 2nd and higher orders’ derivative values of direct current are summarized as the core to judge CF by analyzing the physical characteristics of the direct current waveform of the converter station in CF. Then, the Daubechies wavelet coefficient that can represent the 2nd and higher order derivative values of direct current is derived. Once the wavelet coefficients of the sampling points are detected to exceed the threshold, the occurrence of CF is confirmed. Furthermore, by instantly increasing advanced firing angle β in the inverter side, an additional emergency control strategy to prevent subsequent CF is proposed. Eventually, with simulations of the benchmark model, the effectiveness and superiorities of the proposed detection method and additional control strategy in accuracy and rapidity are verified.
Yang, Jun; Liu, Yuanying; Wu, Xiaoping
2017-11-01
We present a 3-D electrical resistivity modelling with long electrode sources using finite element method on unstructured tetrahedral grids. The radius and resistivity of the electrode is neglected and the electrode can be regarded as a line source with finite length in our modelling. An approximated equation for determining the current density along the electrode is derived for current density correction in heterogeneous media. Electrical fields excited by arbitrary long electrode sources in heterogeneous conductive media can be simulated. Both total- and secondary-potential methods are implemented in the simulation. The analytic electrical potentials of an arbitrary long electrode source in a conductive half-space is derived and used for accuracy analysis in the numerical simulations. The apparent resistivities for survey arrays with long electrode sources are proposed based on the analytic solution of the half-space model. The responses of electrical fields excited by point electrode and long electrode sources to resistivity anomalies are compared with ground and borehole simulations, which shows that the arrays with long electrode sources are more sensitive to the anomalies than those with point electrode sources. A time-lapsed monitoring for hydraulic fracturing in oil field using the production wells as long electrode sources is also simulated, which indicates that the borehole potential data of the long electrode source array can help assess the location of the fracture zone.
Directory of Open Access Journals (Sweden)
Yanzhao He
2017-02-01
Full Text Available The start-up current control of the high-speed brushless DC (HS-BLDC motor is a challenging research topic. To effectively control the start-up current of the sensorless HS-BLDC motor, an adaptive control method is proposed based on the adaptive neural network (ANN inverse system and the two degrees of freedom (2-DOF internal model controller (IMC. The HS-BLDC motor is identified by the online least squares support vector machine (OLS-SVM algorithm to regulate the ANN inverse controller parameters in real time. A pseudo linear system is developed by introducing the constructed real-time inverse system into the original HS-BLDC motor system. Based on the characteristics of the pseudo linear system, an extra closed-loop feedback control strategy based on the 2-DOF IMC is proposed to improve the transient response performance and enhance the stability of the control system. The simulation and experimental results show that the proposed control method is effective and perfect start-up current tracking performance is achieved.
2016-01-01
This book aims to cover different aspects of Bias Temperature Instability (BTI). BTI remains as an important reliability concern for CMOS transistors and circuits. Development of BTI resilient technology relies on utilizing artefact-free stress and measurement methods and suitable physics-based models for accurate determination of degradation at end-of-life, and understanding the gate insulator process impact on BTI. This book discusses different ultra-fast characterization techniques for recovery artefact free BTI measurements. It also covers different direct measurements techniques to access pre-existing and newly generated gate insulator traps responsible for BTI. The book provides a consistent physical framework for NBTI and PBTI respectively for p- and n- channel MOSFETs, consisting of trap generation and trapping. A physics-based compact model is presented to estimate measured BTI degradation in planar Si MOSFETs having differently processed SiON and HKMG gate insulators, in planar SiGe MOSFETs and also...
2010-10-14
... Corporation Model DC- 10-10, DC-10-10F, DC-10-30, DC-10-30F (KDC-10), DC-10-40, and DC-10-40F Airplanes AGENCY...-10F, DC-10-30, DC-10-30F (KDC-10), DC-10-40, and DC-10- 40F airplanes, certificated in any category...
Several methods applied to measuring residual stress in a known specimen
International Nuclear Information System (INIS)
Prime, M.B.; Rangaswamy, P.; Daymond, M.R.; Abelin, T.G.
1998-01-01
In this study, a beam with a precisely known residual stress distribution provided a unique experimental opportunity. A plastically bent beam was carefully prepared in order to provide a specimen with a known residual stress profile. 21Cr-6Ni-9Mn austenitic stainless steel was obtained as 43 mm square forged stock. Several methods were used to determine the residual stresses, and the results were compared to the known values. Some subtleties of applying the various methods were exposed
Method of applying single higher order polynomial basis function over multiple domains
CSIR Research Space (South Africa)
Lysko, AA
2010-03-01
Full Text Available M) with higher-order polynomial basis functions, and applied to a surface form of the electrical field integral equation, under thin wire approximation. The main advantage of the proposed method is in permitting to reduce the required number of unknowns when...
Method of applying single higher order polynomial basis function over multiple domains
CSIR Research Space (South Africa)
Lysko, AA
2010-03-01
Full Text Available A novel method has been devised where one set of higher order polynomial-based basis functions can be applied over several wire segments, thus permitting to decouple the number of unknowns from the number of segments, and so from the geometrical...
21 CFR 111.320 - What requirements apply to laboratory methods for testing and examination?
2010-04-01
... 21 Food and Drugs 2 2010-04-01 2010-04-01 false What requirements apply to laboratory methods for testing and examination? 111.320 Section 111.320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION CURRENT GOOD MANUFACTURING...
Critical path method applied to research project planning: Fire Economics Evaluation System (FEES)
Earl B. Anderson; R. Stanton Hales
1986-01-01
The critical path method (CPM) of network analysis (a) depicts precedence among the many activities in a project by a network diagram; (b) identifies critical activities by calculating their starting, finishing, and float times; and (c) displays possible schedules by constructing time charts. CPM was applied to the development of the Forest Service's Fire...
DEFF Research Database (Denmark)
Zambach, Sine; Madsen, Bodil Nistrup
2009-01-01
By applying formal terminological methods to model an ontology within the domain of enzyme inhibition, we aim to clarify concepts and to obtain consistency. Additionally, we propose a procedure for implementing this ontology in OWL with the aim of obtaining a strict structure which can form...
[Alternative medicine methods applied in patients before surgical treatment of lumbar discopathy].
Rutkowska, E; Kamiński, S; Kucharczyk, A
2001-01-01
Case records of 200 patients operated on in 1998/99 for herniated lumbar disc in Neurosurgery Dept. showed that 95 patients (47.5%) had been treated previously by 148 alternative medical or non-medical procedures. The authors discuss the problem of non-conventional treatment methods applied for herniated lumbar disc by professionals or non professionals. The procedures are often dangerous.
The Effect Of The Applied Performance Methods On The Objective Of The Managers
Directory of Open Access Journals (Sweden)
Derya Kara
2009-09-01
Full Text Available Within the changing management concept, employees and employers have the constant feeling of keeping up with the changing environment. In this regard, performance evaluation activities are regarded as an indispensable element. Data obtained from the results of the performance evaluation activities, shed light on the development of the employees and enable the enterprises to stand in the fierce competitive environment. This study sets out to find out the effect of the applied performance methods on the objective of the managers. The population of the study comprises 182 hotel enterprises with five stars operating in Antalya, İzmir and Muğla with 2184 managers. Sample population was comprised of 578 managers. The results of the study suggest that the effect of the applied performance methods on the objective of the managers counts. The objective of the managers applying 360-degree performance evaluation method is found to be “finding out the training and development needs”, while the objective of the managers applying conventional performance evaluation methods is found to be “enhancing the existing performance”.
Rajabi, A; Dabiri, A
2012-01-01
Activity Based Costing (ABC) is one of the new methods began appearing as a costing methodology in the 1990's. It calculates cost price by determining the usage of resources. In this study, ABC method was used for calculating cost price of remedial services in hospitals. To apply ABC method, Shahid Faghihi Hospital was selected. First, hospital units were divided into three main departments: administrative, diagnostic, and hospitalized. Second, activity centers were defined by the activity analysis method. Third, costs of administrative activity centers were allocated into diagnostic and operational departments based on the cost driver. Finally, with regard to the usage of cost objectives from services of activity centers, the cost price of medical services was calculated. The cost price from ABC method significantly differs from tariff method. In addition, high amount of indirect costs in the hospital indicates that capacities of resources are not used properly. Cost price of remedial services with tariff method is not properly calculated when compared with ABC method. ABC calculates cost price by applying suitable mechanisms but tariff method is based on the fixed price. In addition, ABC represents useful information about the amount and combination of cost price services.
Large Signal Stabilization of Hybrid AC/DC Micro-Grids Using Nonlinear Robust Controller
Directory of Open Access Journals (Sweden)
Reza Pejmanfar
2017-12-01
Full Text Available This paper presents a robust nonlinear integrated controller to improve stability of hybrid AC/DC micro-grids under islanding mode. The proposed controller includes two independent controllers where each one is responsible to control one part of the system. First controller will improve the stability of input DC/DC converter. Using this controller, the voltage of DC bus is fully stabilized such that when a large disturbance occurs, its voltage will become constant without any significant dynamic. The necessity of DC bus regulation which has not been considered in previous studies, is imminent as it not only improves voltage stability of the micro-grid but also protects consumers which are directly connected to the DC bus, against voltage variations. Frequency stability of the micro-grid is provided by the second proposed controller which is applied to output DC/AC converter of the micro-grid. Adaptive method is used to make the controllers proposed in this paper, robust. Duty cycle of converters switches are adjusted such that voltage and frequency of the micro-grid are set on the desired value in minimum possible time under transient disturbances and uncertainty of the loads as well as micro-sources characteristics.
Early Oscillation Detection for Hybrid DC/DC Converter Fault Diagnosis
Wang, Bright L.
2011-01-01
This paper describes a novel fault detection technique for hybrid DC/DC converter oscillation diagnosis. The technique is based on principles of feedback control loop oscillation and RF signal modulations, and Is realized by using signal spectral analysis. Real-circuit simulation and analytical study reveal critical factors of the oscillation and indicate significant correlations between the spectral analysis method and the gain/phase margin method. A stability diagnosis index (SDI) is developed as a quantitative measure to accurately assign a degree of stability to the DC/DC converter. This technique Is capable of detecting oscillation at an early stage without interfering with DC/DC converter's normal operation and without limitations of probing to the converter.
Interleaved Self-Oscillating Class E Derived Resonant DC/DC Converters
DEFF Research Database (Denmark)
Kovacevic, Milovan; Knott, Arnold; Andersen, Michael A. E.
2012-01-01
A new method for achieving self-oscillating, self-interleaved operation of class E derived resonant DC/DC converters is presented. The proposed method is suitable for operation at frequencies in the Very High Frequency (VHF) band. Interleaved and self-oscillating modes of operation are achieved......% in continuous operation....
Energy Technology Data Exchange (ETDEWEB)
Polenov, Dieter
2010-01-15
The paper discusses DC/DC converters for integration of double layer condensers into the onboard power system. First, requirements on DC/DC converters are listed and compared on the basis of three exemplary applications. A DC/DC converter concept is developed for decoupling transient high-power loads like electric steering systems. Three different topologies are compared using a specially developed method in order to find the best solution for the given application. In order to establish adequate criteria for selecting the switching frequency and inductivities of storage throttles, the influence of the trottle power change on the switching characteristics of the MOSFETs and on certain ranges of EMP interference emissions is investigated. As methods of optimising the operation of the synchronous rectifiers, parallel connection of Schottky diodes and synchronous rectifiers as well as the variation of the shut-off dead times of synchronous rectifiers were investigated. Further, a concept for converter control was developed in consideration of the intended application and topology. Finally, selected aspects for implementation of the DC/DC converter concept are presented as well as the results of experimental investigations.
DEFF Research Database (Denmark)
Ma, Siyuan; Wang, Haoran; Tang, Junchaojie
2016-01-01
In single-phase inverters, DC-link capacitors are installed at the DC-link to buffer the ripple power between the AC side and DC side. Active decoupling methods introduce additional circuits at the DC side or AC side to partially or fully supply the ripple power. So that the demanded DC-link capa......In single-phase inverters, DC-link capacitors are installed at the DC-link to buffer the ripple power between the AC side and DC side. Active decoupling methods introduce additional circuits at the DC side or AC side to partially or fully supply the ripple power. So that the demanded DC...
An applied study using systems engineering methods to prioritize green systems options
Energy Technology Data Exchange (ETDEWEB)
Lee, Sonya M [Los Alamos National Laboratory; Macdonald, John M [Los Alamos National Laboratory
2009-01-01
For many years, there have been questions about the effectiveness of applying different green solutions. If you're building a home and wish to use green technologies, where do you start? While all technologies sound promising, which will perform the best over time? All this has to be considered within the cost and schedule of the project. The amount of information available on the topic can be overwhelming. We seek to examine if Systems Engineering methods can be used to help people choose and prioritize technologies that fit within their project and budget. Several methods are used to gain perspective into how to select the green technologies, such as the Analytic Hierarchy Process (AHP) and Kepner-Tregoe. In our study, subjects applied these methods to analyze cost, schedule, and trade-offs. Results will document whether the experimental approach is applicable to defining system priorities for green technologies.
Economic consequences assessment for scenarios and actual accidents do the same methods apply
International Nuclear Information System (INIS)
Brenot, J.
1991-01-01
Methods for estimating the economic consequences of major technological accidents, and their corresponding computer codes, are briefly presented with emphasis on the basic choices. When applied to hypothetic scenarios, those methods give results that are of interest for risk managers with a decision aiding perspective. Simultaneously the various costs, and the procedures for their estimation are reviewed for some actual accidents (Three Mile Island, Chernobyl,..). These costs are used in a perspective of litigation and compensation. The comparison of the methods used and cost estimates obtained for scenarios and actual accidents shows the points of convergence and discrepancies that are discussed
Applying the Support Vector Machine Method to Matching IRAS and SDSS Catalogues
Directory of Open Access Journals (Sweden)
Chen Cao
2007-10-01
Full Text Available This paper presents results of applying a machine learning technique, the Support Vector Machine (SVM, to the astronomical problem of matching the Infra-Red Astronomical Satellite (IRAS and Sloan Digital Sky Survey (SDSS object catalogues. In this study, the IRAS catalogue has much larger positional uncertainties than those of the SDSS. A model was constructed by applying the supervised learning algorithm (SVM to a set of training data. Validation of the model shows a good identification performance (∼ 90% correct, better than that derived from classical cross-matching algorithms, such as the likelihood-ratio method used in previous studies.
Pfeffer, Tobias; Pollet, Lode
2017-04-01
We present the construction and stochastic summation of rooted-tree diagrams, based on the expansion of a root finding algorithm applied to the Dyson-Schwinger equations. The mathematical formulation shows superior convergence properties compared to the bold diagrammatic Monte Carlo approach and the developed algorithm allows one to tackle generic high-dimensional integral equations, to avoid the curse of dealing explicitly with high-dimensional objects and to access non-perturbative regimes. The sign problem remains the limiting factor, but it is not found to be worse than in other approaches. We illustrate the method for {φ }4 theory but note that it applies in principle to any model.
Design and Implementation of Digital Current Mode Controller for DC-DC Converters
DEFF Research Database (Denmark)
Taeed, Fazel
In the recent decades, shortage of fossil fuels and global warming have increased the demand for renewable energy resources. Dc-dc converters are widely used in renewable energy systems, electric vehicles, and battery chargers. In practical applications, dc-dc converters are required to be regula......In the recent decades, shortage of fossil fuels and global warming have increased the demand for renewable energy resources. Dc-dc converters are widely used in renewable energy systems, electric vehicles, and battery chargers. In practical applications, dc-dc converters are required...... to be regulated by a closed-loop controller. The Peak Current Mode Control (PCMC) is one of the most promising control methods for dc-dc converters. It has been known for high bandwidth (speed), and inherent current protection. Increasing the controller bandwidth decreases the output filter size and cost. Analog...... controllers (including PCMC) are sensitive to temperature drift, component aging and noise. Digital controllers do not have the aforementioned drawbacks of analog controllers; but they have lower bandwidth than analog controllers due to the sampling and calculation delays. Generally, analog controllers have...
Study on the Control Algorithm of Two-Stage DC-DC Converter for Electric Vehicles
Directory of Open Access Journals (Sweden)
Changhao Piao
2014-01-01
Full Text Available The fast response, high efficiency, and good reliability are very important characteristics to electric vehicles (EVs dc/dc converters. Two-stage dc-dc converter is a kind of dc-dc topologies that can offer those characteristics to EVs. Presently, nonlinear control is an active area of research in the field of the control algorithm of dc-dc converters. However, very few papers research on two-stage converter for EVs. In this paper, a fixed switching frequency sliding mode (FSFSM controller and double-integral sliding mode (DISM controller for two-stage dc-dc converter are proposed. And a conventional linear control (lag is chosen as the comparison. The performances of the proposed FSFSM controller are compared with those obtained by the lag controller. In consequence, the satisfactory simulation and experiment results show that the FSFSM controller is capable of offering good large-signal operations with fast dynamical responses to the converter. At last, some other simulation results are presented to prove that the DISM controller is a promising method for the converter to eliminate the steady-state error.
Programmable dc motor controller
Hopwood, J. E.
1982-11-01
A portable programmable dc motor controller, with features not available on commercial instruments was developed for controlling fixtures during welding processes. The controller can be used to drive any dc motor having tachometer feedback and motor requirements not exceeding 30 volts, 3 amperes. Among the controller's features are delayed start time, upslope time, speed, and downslope time.
Expression of DC-SIGN and DC-SIGNRs in placentas of HIV-positive patients
Directory of Open Access Journals (Sweden)
Komala Pillay
2014-09-01
Full Text Available Background. Human dendritic cell-specific intracellular adhesion molecule-3 (ICAM3-grabbing non-integrin (DC-SIGN is a mannose-binding lectin that initiates interaction between dendritic cells and resting T-lymphocytes. DC-SIGN is highly expressed in placental tissue on dendritic cells and Hofbauer cells, and it is suggested that HIV may become adsorbed to DC-SIGN on Hofbauer cells as part of the mechanism of mother-to-child HIV transmission. A possible mechanism of transfer of the virus from the Hofbauer cells to the fetus is the subsequent adsorption to DC-SIGN-related molecules (DC-SIGNRs, present on immediately adjacent capillary vascular endothelium. However, data on DC-SIGN and DC-SIGNR expression in the placenta are few. Methods. Forty term placentas from HIV-positive mothers and 21 term placentas from HIV-negative mothers underwent immunohistochemistry staining for DC-SIGN and DC-SIGNR expression. Five random sets of 10 villi were assessed, and the average number of positive cells were counted in each case. In addition, where possible, maternal and cord blood viral loads and maternal CD4+ counts were performed in the HIV-positive group only. Results. The median maternal CD4+ count was 377 cells/µl and 27% of participants had undetectable viral loads; the median detectable viral load was 3.72 log. Most (97% of the cord bloods tested in infants from HIV-positive mothers had lower than detectable viral loads. HIV-positive cases had significantly greater expression of both DC-SIGNRs (median values in HIV-positive cases, 14.5 positive cells/10 villi (pc/10villi, compared with 11 pc/10villi in HIV-negative cases, p=0.020 and DC-SIGN (median value in HIV-positive cases, 26.5 pc/10villi, compared with 23 pc/10villi in HIV-negative cases, p=0.037. DC-SIGNR expression was also noted in Hofbauer cells and decidual macrophages in addition to endothelium (reported currently. There was no difference in expression of DC-SIGN and DC-SIGNRs in patients
Directory of Open Access Journals (Sweden)
Gang Chen
2015-07-01
Full Text Available A new control method for an electromagnetic unmanned robot applied to automotive testing (URAT and based on improved Smith predictor compensator, and considering a time delay, is proposed. The mechanical system structure and the control system structure are presented. The electromagnetic URAT adopts pulse width modulation (PWM control, while the displacement and the current doubles as a closed-loop control strategy. The coordinated control method of multiple manipulators for the electromagnetic URAT, e.g., a skilled human driver with intelligent decision-making ability is provided, and the improved Smith predictor compensator controller for the electromagnetic URAT considering a time delay is designed. Experiments are conducted using a Ford FOCUS automobile. Comparisons between the PID control method and the proposed method are conducted. Experimental results show that the proposed method can achieve the accurate tracking of the target vehicle's speed and reduce the mileage derivation of autonomous driving, which meets the requirements of national test standards.
Optimization methods of the net emission computation applied to cylindrical sodium vapor plasma
International Nuclear Information System (INIS)
Hadj Salah, S.; Hajji, S.; Ben Hamida, M. B.; Charrada, K.
2015-01-01
An optimization method based on a physical analysis of the temperature profile and different terms in the radiative transfer equation is developed to reduce the time computation of the net emission. This method has been applied for the cylindrical discharge in sodium vapor. Numerical results show a relative error of spectral flux density values lower than 5% with an exact solution, whereas the computation time is about 10 orders of magnitude less. This method is followed by a spectral method based on the rearrangement of the lines profile. Results are shown for Lorentzian profile and they demonstrated a relative error lower than 10% with the reference method and gain in computation time about 20 orders of magnitude
Multigrid method applied to the solution of an elliptic, generalized eigenvalue problem
Energy Technology Data Exchange (ETDEWEB)
Alchalabi, R.M. [BOC Group, Murray Hill, NJ (United States); Turinsky, P.J. [North Carolina State Univ., Raleigh, NC (United States)
1996-12-31
The work presented in this paper is concerned with the development of an efficient MG algorithm for the solution of an elliptic, generalized eigenvalue problem. The application is specifically applied to the multigroup neutron diffusion equation which is discretized by utilizing the Nodal Expansion Method (NEM). The underlying relaxation method is the Power Method, also known as the (Outer-Inner Method). The inner iterations are completed using Multi-color Line SOR, and the outer iterations are accelerated using Chebyshev Semi-iterative Method. Furthermore, the MG algorithm utilizes the consistent homogenization concept to construct the restriction operator, and a form function as a prolongation operator. The MG algorithm was integrated into the reactor neutronic analysis code NESTLE, and numerical results were obtained from solving production type benchmark problems.
Least Square NUFFT Methods Applied to 2D and 3D Radially Encoded MR Image Reconstruction
Song, Jiayu; Liu, Qing H.; Gewalt, Sally L.; Cofer, Gary; Johnson, G. Allan
2009-01-01
Radially encoded MR imaging (MRI) has gained increasing attention in applications such as hyperpolarized gas imaging, contrast-enhanced MR angiography, and dynamic imaging, due to its motion insensitivity and improved artifact properties. However, since the technique collects k-space samples nonuniformly, multidimensional (especially 3D) radially sampled MRI image reconstruction is challenging. The balance between reconstruction accuracy and speed becomes critical when a large data set is processed. Kaiser-Bessel gridding reconstruction has been widely used for non-Cartesian reconstruction. The objective of this work is to provide an alternative reconstruction option in high dimensions with on-the-fly kernels calculation. The work develops general multi-dimensional least square nonuniform fast Fourier transform (LS-NUFFT) algorithms and incorporates them into a k-space simulation and image reconstruction framework. The method is then applied to reconstruct the radially encoded k-space, although the method addresses general nonuniformity and is applicable to any non-Cartesian patterns. Performance assessments are made by comparing the LS-NUFFT based method with the conventional Kaiser-Bessel gridding method for 2D and 3D radially encoded computer simulated phantoms and physically scanned phantoms. The results show that the LS-NUFFT reconstruction method has better accuracy-speed efficiency than the Kaiser-Bessel gridding method when the kernel weights are calculated on the fly. The accuracy of the LS-NUFFT method depends on the choice of scaling factor, and it is found that for a particular conventional kernel function, using its corresponding deapodization function as scaling factor and utilizing it into the LS-NUFFT framework has the potential to improve accuracy. When a cosine scaling factor is used, in particular, the LS-NUFFT method is faster than Kaiser-Bessel gridding method because of a quasi closed-form solution. The method is successfully applied to 2D and
Langer, Stefan
2014-11-01
For unstructured finite volume methods an agglomeration multigrid with an implicit multistage Runge-Kutta method as a smoother is developed for solving the compressible Reynolds averaged Navier-Stokes (RANS) equations. The implicit Runge-Kutta method is interpreted as a preconditioned explicit Runge-Kutta method. The construction of the preconditioner is based on an approximate derivative. The linear systems are solved approximately with a symmetric Gauss-Seidel method. To significantly improve this solution method grid anisotropy is treated within the Gauss-Seidel iteration in such a way that the strong couplings in the linear system are resolved by tridiagonal systems constructed along these directions of strong coupling. The agglomeration strategy is adapted to this procedure by taking into account exactly these anisotropies in such a way that a directional coarsening is applied along these directions of strong coupling. Turbulence effects are included by a Spalart-Allmaras model, and the additional transport-type equation is approximately solved in a loosely coupled manner with the same method. For two-dimensional and three-dimensional numerical examples and a variety of differently generated meshes we show the wide range of applicability of the solution method. Finally, we exploit the GMRES method to determine approximate spectral information of the linearized RANS equations. This approximate spectral information is used to discuss and compare characteristics of multistage Runge-Kutta methods.
The Topologies Research of a Soft Switching Bidirectional DC/DC Converter
DEFF Research Database (Denmark)
Zhang, Qi; Zhang, Yongping; Sun, Xiangdong
2017-01-01
A soft-switching solution implemented to the traditional bidirectional DC/DC converter is developed. The soft-switching cell, which composed of three auxiliary switches, one resonant capacitor and one resonant inductor, is equipped in the traditional bidirectional DC/DC converter to realize circuit...... from a hard turning off process in one of the auxiliary switches, while the others experience the soft operation. As for the other method, the zero voltage or zero current transmissions in all switches are realized, however, the relative higher but fixed conduction losses are introduced by the resonant...... circle. And the proposed topology of bidirectional soft-switching dc-dc converter(TASBC) performs ideal soft switching at boost operations. The characteristics of the proposed converter has been verified by MATLAB simulations and experimental results....
2010-07-07
... Corporation Model DC- 10-10, DC-10-10F, DC-10-30, DC-10-30F (KDC-10), DC-10-40, and DC-10-40F Airplanes AGENCY... propose to adopt a new airworthiness directive (AD) for certain Model DC-10-10, DC-10-10F, DC-10-30, DC-10-30F (KDC-10), DC-10- 40, and DC-10-40F airplanes. This proposed AD would require installing a support...
Applying Mathematical Optimization Methods to an ACT-R Instance-Based Learning Model.
Said, Nadia; Engelhart, Michael; Kirches, Christian; Körkel, Stefan; Holt, Daniel V
2016-01-01
Computational models of cognition provide an interface to connect advanced mathematical tools and methods to empirically supported theories of behavior in psychology, cognitive science, and neuroscience. In this article, we consider a computational model of instance-based learning, implemented in the ACT-R cognitive architecture. We propose an approach for obtaining mathematical reformulations of such cognitive models that improve their computational tractability. For the well-established Sugar Factory dynamic decision making task, we conduct a simulation study to analyze central model parameters. We show how mathematical optimization techniques can be applied to efficiently identify optimal parameter values with respect to different optimization goals. Beyond these methodological contributions, our analysis reveals the sensitivity of this particular task with respect to initial settings and yields new insights into how average human performance deviates from potential optimal performance. We conclude by discussing possible extensions of our approach as well as future steps towards applying more powerful derivative-based optimization methods.
The 2D Spectral Intrinsic Decomposition Method Applied to Image Analysis
Directory of Open Access Journals (Sweden)
Samba Sidibe
2017-01-01
Full Text Available We propose a new method for autoadaptive image decomposition and recomposition based on the two-dimensional version of the Spectral Intrinsic Decomposition (SID. We introduce a faster diffusivity function for the computation of the mean envelope operator which provides the components of the SID algorithm for any signal. The 2D version of SID algorithm is implemented and applied to some very known images test. We extracted relevant components and obtained promising results in images analysis applications.
Accuracy of the Adomian decomposition method applied to the Lorenz system
International Nuclear Information System (INIS)
Hashim, I.; Noorani, M.S.M.; Ahmad, R.; Bakar, S.A.; Ismail, E.S.; Zakaria, A.M.
2006-01-01
In this paper, the Adomian decomposition method (ADM) is applied to the famous Lorenz system. The ADM yields an analytical solution in terms of a rapidly convergent infinite power series with easily computable terms. Comparisons between the decomposition solutions and the fourth-order Runge-Kutta (RK4) numerical solutions are made for various time steps. In particular we look at the accuracy of the ADM as the Lorenz system changes from a non-chaotic system to a chaotic one
Applying the Goal-Question-Indicator-Metric (GQIM) Method to Perform Military Situational Analysis
2016-05-11
MAXIMUM 200 WORDS ) When developing situational awareness in support of military operations, the U.S. armed forces use a mnemonic, or memory aide, to...REV-03.18.2016.0 Applying the Goal- Question -Indicator- Metric (GQIM) Method to Perform Military Situational Analysis Douglas Gray May 2016...Acknowledgments The subject matter covered in this technical note evolved from an excellent question from Capt. Tomomi Ogasawara, Japan Ground Self
Applied Ecosystem Analysis - - a Primer : EDT the Ecosystem Diagnosis and Treatment Method.
Energy Technology Data Exchange (ETDEWEB)
Lestelle, Lawrence C.; Mobrand, Lars E.
1996-05-01
The aim of this document is to inform and instruct the reader about an approach to ecosystem management that is based upon salmon as an indicator species. It is intended to provide natural resource management professionals with the background information needed to answer questions about why and how to apply the approach. The methods and tools the authors describe are continually updated and refined, so this primer should be treated as a first iteration of a sequentially revised manual.
Applied ecosystem analysis - a primer; the ecosystem diagnosis and treatment method
International Nuclear Information System (INIS)
Lestelle, L.C.; Mobrand, L.E.; Lichatowich, J.A.; Vogel, T.S.
1996-05-01
The aim of this document is to inform and instruct the reader about an approach to ecosystem management that is based upon salmon as an indicator species. It is intended to provide natural resource management professionals with the background information needed to answer questions about why and how to apply the approach. The methods and tools the authors describe are continually updated and refined, so this primer should be treated as a first iteration of a sequentially revised manual
A Comparison of Parametric and Non-Parametric Methods Applied to a Likert Scale
Mircioiu, Constantin; Atkinson, Jeffrey
2017-01-01
A trenchant and passionate dispute over the use of parametric versus non-parametric methods for the analysis of Likert scale ordinal data has raged for the past eight decades. The answer is not a simple “yes” or “no” but is related to hypotheses, objectives, risks, and paradigms. In this paper, we took a pragmatic approach. We applied both types of methods to the analysis of actual Likert data on responses from different professional subgroups of European pharmacists regarding competencies fo...
A method for finding the ridge between saddle points applied to rare event rate estimates
DEFF Research Database (Denmark)
Maronsson, Jon Bergmann; Jónsson, Hannes; Vegge, Tejs
2012-01-01
A method is presented for finding the ridge between first order saddle points on a multidimensional surface. For atomic scale systems, such saddle points on the energy surface correspond to atomic rearrangement mechanisms. Information about the ridge can be used to test the validity of the harmonic...... to the path. The method is applied to Al adatom diffusion on the Al(100) surface to find the ridge between 2-, 3- and 4-atom concerted displacements and hop mechanisms. A correction to the harmonic approximation of transition state theory was estimated by direct evaluation of the configuration integral along...
Development of a tracking method for augmented reality applied to nuclear plant maintenance work
International Nuclear Information System (INIS)
Shimoda, Hiroshi; Maeshima, Masayuki; Nakai, Toshinori; Bian, Zhiqiang; Ishii, Hirotake; Yoshikawa, Hidekazu
2005-01-01
In this paper, a plant maintenance support method is described, which employs the state-of-the-art information technology, Augmented Reality (AR), in order to improve efficiency of NPP maintenance work and to prevent from human error. Although AR has a great possibility to support various works in real world, it is difficult to apply it to actual work support because the tracking method is the bottleneck for the practical use. In this study, a bar code marker tracking method is proposed to apply AR system for a maintenance work support in NPP field. The proposed method calculates the users position and orientation in real time by two long markers, which are captured by the user-mounted camera. The markers can be easily pasted on the pipes in plant field, and they can be easily recognized in long distance in order to reduce the number of pasted markers in the work field. Experiments were conducted in a laboratory and plant field to evaluate the proposed method. The results show that (1) fast and stable tracking can be realized, (2) position error in camera view is less than 1%, which is almost perfect under the limitation of camera resolution, and (3) it is relatively difficult to catch two markers in one camera view especially in short distance
Lessons learned applying CASE methods/tools to Ada software development projects
Blumberg, Maurice H.; Randall, Richard L.
1993-01-01
This paper describes the lessons learned from introducing CASE methods/tools into organizations and applying them to actual Ada software development projects. This paper will be useful to any organization planning to introduce a software engineering environment (SEE) or evolving an existing one. It contains management level lessons learned, as well as lessons learned in using specific SEE tools/methods. The experiences presented are from Alpha Test projects established under the STARS (Software Technology for Adaptable and Reliable Systems) project. They reflect the front end efforts by those projects to understand the tools/methods, initial experiences in their introduction and use, and later experiences in the use of specific tools/methods and the introduction of new ones.
Garcia, Diego; Moro, Claudia Maria Cabral; Cicogna, Paulo Eduardo; Carvalho, Deborah Ribeiro
2013-01-01
Clinical guidelines are documents that assist healthcare professionals, facilitating and standardizing diagnosis, management, and treatment in specific areas. Computerized guidelines as decision support systems (DSS) attempt to increase the performance of tasks and facilitate the use of guidelines. Most DSS are not integrated into the electronic health record (EHR), ordering some degree of rework especially related to data collection. This study's objective was to present a method for integrating clinical guidelines into the EHR. The study developed first a way to identify data and rules contained in the guidelines, and then incorporate rules into an archetype-based EHR. The proposed method tested was anemia treatment in the Chronic Kidney Disease Guideline. The phases of the method are: data and rules identification; archetypes elaboration; rules definition and inclusion in inference engine; and DSS-EHR integration and validation. The main feature of the proposed method is that it is generic and can be applied toany type of guideline.
Applying the response matrix method for solving coupled neutron diffusion and transport problems
International Nuclear Information System (INIS)
Sibiya, G.S.
1980-01-01
The numerical determination of the flux and power distribution in the design of large power reactors is quite a time-consuming procedure if the space under consideration is to be subdivided into very fine weshes. Many computing methods applied in reactor physics (such as the finite-difference method) require considerable computing time. In this thesis it is shown that the response matrix method can be successfully used as an alternative approach to solving the two-dimension diffusion equation. Furthermore it is shown that sufficient accuracy of the method is achieved by assuming a linear space dependence of the neutron currents on the boundaries of the geometries defined for the given space. (orig.) [de
Applying some methods to process the data coming from the nuclear reactions
International Nuclear Information System (INIS)
Suleymanov, M.K.; Abdinov, O.B.; Belashev, B.Z.
2010-01-01
Full text : The methods of a posterior increasing the resolution of the spectral lines are offered to process the data coming from the nuclear reactions. The methods have applied to process the data coming from the nuclear reactions at high energies. They give possibilities to get more detail information on a structure of the spectra of particles emitted in the nuclear reactions. The nuclear reactions are main source of the information on the structure and physics of the atomic nuclei. Usually the spectrums of the fragments of the reactions are complex ones. Apparently it is not simple to extract the necessary for investigation information. In the talk we discuss the methods of a posterior increasing the resolution of the spectral lines. The methods could be useful to process the complex data coming from the nuclear reactions. We consider the Fourier transformation method and maximum entropy one. The complex structures were identified by the method. One can see that at lest two selected points are indicated by the method. Recent we presented a talk where we shown that the results of the analyzing the structure of the pseudorapidity spectra of charged relativistic particles with ≥ 0.7 measured in Au+Em and Pb+Em at AGS and SPS energies using the Fourier transformation method and maximum entropy one. The dependences of these spectra on the number of fast target protons were studied. These distribution shown visually some plateau and shoulder that was at least three selected points on the distributions. The plateaus become wider in PbEm reactions. The existing of plateau is necessary for the parton models. The maximum entropy method could confirm the existing of the plateau and the shoulder on the distributions. The figure shows the results of applying the maximum entropy method. One can see that the method indicates several clean selected points. Some of them same with observed visually ones. We would like to note that the Fourier transformation method could not
A New Sliding Mode Controller for DC/DC Converters in Photovoltaic Systems
Directory of Open Access Journals (Sweden)
M. Sarvi
2013-01-01
Full Text Available DC/DC converters are widely used in many industrial and electrical systems. As DC/DC converters are nonlinear and time-variant systems, the application of linear control techniques for the control of these converters is not suitable. In this paper, a new sliding mode controller is proposed as the indirect control method and compared to a simple direct control method in order to control a buck converter in photovoltaic applications. The solar arrays are dependent power sources with nonlinear voltage-current characteristics under different environmental conditions (insolation and temperature. From this point of view, the DC/DC converter is particularly suitable for the application of the sliding mode control in photovoltaic application, because of its controllable states. Simulations are performed in Matlab/Simulink software. The simulation results are presented for a step change in reference voltage and input voltage as well as step load variations. The simulations results of proposed method are compared with the conventional PID controller. The results show the good performance of the proposed sliding mode controller. The proposed method can be used for the other DC/DC converter.
Should methods of correction for multiple comparisons be applied in pharmacovigilance?
Directory of Open Access Journals (Sweden)
Lorenza Scotti
2015-12-01
Full Text Available Purpose. In pharmacovigilance, spontaneous reporting databases are devoted to the early detection of adverse event ‘signals’ of marketed drugs. A common limitation of these systems is the wide number of concurrently investigated associations, implying a high probability of generating positive signals simply by chance. However it is not clear if the application of methods aimed to adjust for the multiple testing problems are needed when at least some of the drug-outcome relationship under study are known. To this aim we applied a robust estimation method for the FDR (rFDR particularly suitable in the pharmacovigilance context. Methods. We exploited the data available for the SAFEGUARD project to apply the rFDR estimation methods to detect potential false positive signals of adverse reactions attributable to the use of non-insulin blood glucose lowering drugs. Specifically, the number of signals generated from the conventional disproportionality measures and after the application of the rFDR adjustment method was compared. Results. Among the 311 evaluable pairs (i.e., drug-event pairs with at least one adverse event report, 106 (34% signals were considered as significant from the conventional analysis. Among them 1 resulted in false positive signals according to rFDR method. Conclusions. The results of this study seem to suggest that when a restricted number of drug-outcome pairs is considered and warnings about some of them are known, multiple comparisons methods for recognizing false positive signals are not so useful as suggested by theoretical considerations.
Energy Technology Data Exchange (ETDEWEB)
Tumelero, Fernanda, E-mail: fernanda.tumelero@yahoo.com.br [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica; Petersen, Claudio Z.; Goncalves, Glenio A.; Lazzari, Luana, E-mail: claudiopeteren@yahoo.com.br, E-mail: gleniogoncalves@yahoo.com.br, E-mail: luana-lazzari@hotmail.com [Universidade Federal de Pelotas (DME/UFPEL), Capao do Leao, RS (Brazil). Instituto de Fisica e Matematica
2015-07-01
In this work, we present a solution of the Neutron Point Kinetics Equations with temperature feedback effects applying the Polynomial Approach Method. For the solution, we consider one and six groups of delayed neutrons precursors with temperature feedback effects and constant reactivity. The main idea is to expand the neutron density, delayed neutron precursors and temperature as a power series considering the reactivity as an arbitrary function of the time in a relatively short time interval around an ordinary point. In the first interval one applies the initial conditions of the problem and the analytical continuation is used to determine the solutions of the next intervals. With the application of the Polynomial Approximation Method it is possible to overcome the stiffness problem of the equations. In such a way, one varies the time step size of the Polynomial Approach Method and performs an analysis about the precision and computational time. Moreover, we compare the method with different types of approaches (linear, quadratic and cubic) of the power series. The answer of neutron density and temperature obtained by numerical simulations with linear approximation are compared with results in the literature. (author)
International Nuclear Information System (INIS)
Vianna Filho, Alfredo Marques
2009-01-01
The economic equipment replacement problem is a central question in Nuclear Engineering. On the one hand, new equipment are more attractive given their best performance, better reliability, lower maintenance cost etc. New equipment, however, require a higher initial investment. On the other hand, old equipment represent the other way around, with lower performance, lower reliability and specially higher maintenance costs, but in contrast having lower financial and insurance costs. The weighting of all these costs can be made with deterministic and probabilistic methods applied to the study of equipment replacement. Two types of distinct problems will be examined, substitution imposed by the wearing and substitution imposed by the failures. In order to solve the problem of nuclear system substitution imposed by wearing, deterministic methods are discussed. In order to solve the problem of nuclear system substitution imposed by failures, probabilistic methods are discussed. The aim of this paper is to present a methodological framework to the choice of the most useful method applied in the problem of nuclear system substitution.(author)
Power secant method applied to natural frequency extraction of Timoshenko beam structures
Directory of Open Access Journals (Sweden)
C.A.N. Dias
Full Text Available This work deals with an improved plane frame formulation whose exact dynamic stiffness matrix (DSM presents, uniquely, null determinant for the natural frequencies. In comparison with the classical DSM, the formulation herein presented has some major advantages: local mode shapes are preserved in the formulation so that, for any positive frequency, the DSM will never be ill-conditioned; in the absence of poles, it is possible to employ the secant method in order to have a more computationally efficient eigenvalue extraction procedure. Applying the procedure to the more general case of Timoshenko beams, we introduce a new technique, named "power deflation", that makes the secant method suitable for the transcendental nonlinear eigenvalue problems based on the improved DSM. In order to avoid overflow occurrences that can hinder the secant method iterations, limiting frequencies are formulated, with scaling also applied to the eigenvalue problem. Comparisons with results available in the literature demonstrate the strength of the proposed method. Computational efficiency is compared with solutions obtained both by FEM and by the Wittrick-Williams algorithm.
Lukemire, Alan T.
1995-05-01
A pulse-width modulated DC-to-DC power converter including a first inductor, i.e. a transformer or an equivalent fixed inductor equal to the inductance of the secondary winding of the transformer, coupled across a source of DC input voltage via a transistor switch which is rendered alternately conductive (ON) and nonconductive (OFF) in accordance with a signal from a feedback control circuit is described. A first capacitor capacitively couples one side of the first inductor to a second inductor which is connected to a second capacitor which is coupled to the other side of the first inductor. A circuit load shunts the second capacitor. A semiconductor diode is additionally coupled from a common circuit connection between the first capacitor and the second inductor to the other side of the first inductor. A current sense transformer generating a current feedback signal for the switch control circuit is directly coupled in series with the other side of the first inductor so that the first capacitor, the second inductor and the current sense transformer are connected in series through the first inductor. The inductance values of the first and second inductors, moreover, are made identical. Such a converter topology results in a simultaneous voltsecond balance in the first inductance and ampere-second balance in the current sense transformer.
Error diffusion method applied to design combined CSG-BSG element used in ICF driver
Zhang, Yixiao; Yao, Xin; Gao, Fuhua; Guo, Yongkang; Wang, Lei; Hou, Xi
2006-08-01
In the final optics assembly of Inertial Confinement Fusion (ICF) driver, Diffractive Optical Elements (DOEs) are applied to achieve some important functions, such as harmonic wave separation, beam sampling, beam smoothing and pulse compression etc. However, in order to optimize the system structure, decrease the energy loss and avoid the damage of laser induction or self-focusing effect, the number of elements used in the ICF system, especially in the final optics assembly, should be minimized. The multiple exposure method has been proposed, for this purpose, to fabricate BSG and CSG on one surface of a silica plate. But the multiple etch processes utilized in this method is complex and will introduce large alignment error. Error diffusion method that based on pulse-density modulation has been widely used in signal processing and computer generated hologram (CGH). In this paper, according to error diffusion method in CGH and partial coherent imaging theory, we present a new method to design coding mask of combine CSG-BSG element with error diffusion method. With the designed mask, only one exposure process is needed in fabricating combined element, which will greatly reduce the fabrication difficulty and avoid the alignment error introduced by multiple etch processes. We illustrate the designed coding mask for CSG-BSG element with this method and compare the intensity distribution of the spatial image in partial coherent imaging system with desired relief.
Solution and study of nodal neutron transport equation applying the LTSN-DiagExp method
International Nuclear Information System (INIS)
Hauser, Eliete Biasotto; Pazos, Ruben Panta; Vilhena, Marco Tullio de; Barros, Ricardo Carvalho de
2003-01-01
In this paper we report advances about the three-dimensional nodal discrete-ordinates approximations of neutron transport equation for Cartesian geometry. We use the combined collocation method of the angular variables and nodal approach for the spatial variables. By nodal approach we mean the iterated transverse integration of the S N equations. This procedure leads to the set of one-dimensional averages angular fluxes in each spatial variable. The resulting system of equations is solved with the LTS N method, first applying the Laplace transform to the set of the nodal S N equations and then obtained the solution by symbolic computation. We include the LTS N method by diagonalization to solve the nodal neutron transport equation and then we outline the convergence of these nodal-LTS N approximations with the help of a norm associated to the quadrature formula used to approximate the integral term of the neutron transport equation. (author)
Li, Yudu; Ma, Sen; Hu, Zhongze; Chen, Jiansheng; Su, Guangda; Dou, Weibei
2015-01-01
Research on brain machine interface (BMI) has been developed very fast in recent years. Numerous feature extraction methods have successfully been applied to electroencephalogram (EEG) classification in various experiments. However, little effort has been spent on EEG based BMI systems regarding familiarity of human faces cognition. In this work, we have implemented and compared the classification performances of four common feature extraction methods, namely, common spatial pattern, principal component analysis, wavelet transform and interval features. High resolution EEG signals were collected from fifteen healthy subjects stimulated by equal number of familiar and novel faces. Principal component analysis outperforms other methods with average classification accuracy reaching 94.2% leading to possible real life applications. Our findings thereby may contribute to the BMI systems for face recognition.
A reflective lens: applying critical systems thinking and visual methods to ecohealth research.
Cleland, Deborah; Wyborn, Carina
2010-12-01
Critical systems methodology has been advocated as an effective and ethical way to engage with the uncertainty and conflicting values common to ecohealth problems. We use two contrasting case studies, coral reef management in the Philippines and national park management in Australia, to illustrate the value of critical systems approaches in exploring how people respond to environmental threats to their physical and spiritual well-being. In both cases, we used visual methods--participatory modeling and rich picturing, respectively. The critical systems methodology, with its emphasis on reflection, guided an appraisal of the research process. A discussion of these two case studies suggests that visual methods can be usefully applied within a critical systems framework to offer new insights into ecohealth issues across a diverse range of socio-political contexts. With this article, we hope to open up a conversation with other practitioners to expand the use of visual methods in integrated research.
A note on the accuracy of spectral method applied to nonlinear conservation laws
Shu, Chi-Wang; Wong, Peter S.
1994-01-01
Fourier spectral method can achieve exponential accuracy both on the approximation level and for solving partial differential equations if the solutions are analytic. For a linear partial differential equation with a discontinuous solution, Fourier spectral method produces poor point-wise accuracy without post-processing, but still maintains exponential accuracy for all moments against analytic functions. In this note we assess the accuracy of Fourier spectral method applied to nonlinear conservation laws through a numerical case study. We find that the moments with respect to analytic functions are no longer very accurate. However the numerical solution does contain accurate information which can be extracted by a post-processing based on Gegenbauer polynomials.
Artificial intelligence methods applied for quantitative analysis of natural radioactive sources
International Nuclear Information System (INIS)
Medhat, M.E.
2012-01-01
Highlights: ► Basic description of artificial neural networks. ► Natural gamma ray sources and problem of detections. ► Application of neural network for peak detection and activity determination. - Abstract: Artificial neural network (ANN) represents one of artificial intelligence methods in the field of modeling and uncertainty in different applications. The objective of the proposed work was focused to apply ANN to identify isotopes and to predict uncertainties of their activities of some natural radioactive sources. The method was tested for analyzing gamma-ray spectra emitted from natural radionuclides in soil samples detected by a high-resolution gamma-ray spectrometry based on HPGe (high purity germanium). The principle of the suggested method is described, including, relevant input parameters definition, input data scaling and networks training. It is clear that there is satisfactory agreement between obtained and predicted results using neural network.
Finite volume and finite element methods applied to 3D laminar and turbulent channel flows
Louda, Petr; Sváček, Petr; Kozel, Karel; Příhoda, Jaromír
2014-12-01
The work deals with numerical simulations of incompressible flow in channels with rectangular cross section. The rectangular cross section itself leads to development of various secondary flow patterns, where accuracy of simulation is influenced by numerical viscosity of the scheme and by turbulence modeling. In this work some developments of stabilized finite element method are presented. Its results are compared with those of an implicit finite volume method also described, in laminar and turbulent flows. It is shown that numerical viscosity can cause errors of same magnitude as different turbulence models. The finite volume method is also applied to 3D turbulent flow around backward facing step and good agreement with 3D experimental results is obtained.
Finite volume and finite element methods applied to 3D laminar and turbulent channel flows
Energy Technology Data Exchange (ETDEWEB)
Louda, Petr; Příhoda, Jaromír [Institute of Thermomechanics, Czech Academy of Sciences, Prague (Czech Republic); Sváček, Petr; Kozel, Karel [Czech Technical University in Prague, Fac. of Mechanical Engineering (Czech Republic)
2014-12-10
The work deals with numerical simulations of incompressible flow in channels with rectangular cross section. The rectangular cross section itself leads to development of various secondary flow patterns, where accuracy of simulation is influenced by numerical viscosity of the scheme and by turbulence modeling. In this work some developments of stabilized finite element method are presented. Its results are compared with those of an implicit finite volume method also described, in laminar and turbulent flows. It is shown that numerical viscosity can cause errors of same magnitude as different turbulence models. The finite volume method is also applied to 3D turbulent flow around backward facing step and good agreement with 3D experimental results is obtained.
The reduction method of statistic scale applied to study of climatic change
International Nuclear Information System (INIS)
Bernal Suarez, Nestor Ricardo; Molina Lizcano, Alicia; Martinez Collantes, Jorge; Pabon Jose Daniel
2000-01-01
In climate change studies the global circulation models of the atmosphere (GCMAs) enable one to simulate the global climate, with the field variables being represented on a grid points 300 km apart. One particular interest concerns the simulation of possible changes in rainfall and surface air temperature due to an assumed increase of greenhouse gases. However, the models yield the climatic projections on grid points that in most cases do not correspond to the sites of major interest. To achieve local estimates of the climatological variables, methods like the one known as statistical down scaling are applied. In this article we show a case in point by applying canonical correlation analysis (CCA) to the Guajira Region in the northeast of Colombia
Watanabe, Takashi; Kurosawa, Kenji; Yoshizawa, Makoto
A Feedback Error Learning (FEL) scheme was found to be applicable to joint angle control by Functional Electrical Stimulation (FES) in our previous study. However, the FEL-FES controller had a problem in learning of the inverse dynamics model (IDM) in some cases. In this paper, methods of applying the FEL to FES control were examined in controlling 1-DOF movement of the wrist joint stimulating 2 muscles through computer simulation under several control conditions with several subject models. The problems in applying FEL to FES controller were suggested to be in restricting stimulation intensity to positive values between the minimum and the maximum intensities and in the case of very small output values of the IDM. Learning of the IDM was greatly improved by considering the IDM output range with setting the minimum ANN output value in calculating ANN connection weight change.
Parallel Implicit Runge-Kutta Methods Applied to Coupled Orbit/Attitude Propagation
Hatten, Noble; Russell, Ryan P.
2017-12-01
A variable-step Gauss-Legendre implicit Runge-Kutta (GLIRK) propagator is applied to coupled orbit/attitude propagation. Concepts previously shown to improve efficiency in 3DOF propagation are modified and extended to the 6DOF problem, including the use of variable-fidelity dynamics models. The impact of computing the stage dynamics of a single step in parallel is examined using up to 23 threads and 22 associated GLIRK stages; one thread is reserved for an extra dynamics function evaluation used in the estimation of the local truncation error. Efficiency is found to peak for typical examples when using approximately 8 to 12 stages for both serial and parallel implementations. Accuracy and efficiency compare favorably to explicit Runge-Kutta and linear-multistep solvers for representative scenarios. However, linear-multistep methods are found to be more efficient for some applications, particularly in a serial computing environment, or when parallelism can be applied across multiple trajectories.
National Aeronautics and Space Administration — The goal of the project was to demonstrate a true direct current (DC) transformer, a new electro-mechanical component with potentially high power applications; in...
Adaptive Curtailment Plan with Energy Storage for AC/DC Combined Distribution Systems
Directory of Open Access Journals (Sweden)
Seungmin Jung
2016-08-01
Full Text Available For developing a large-scale combined system with a number of distributed resources, an appropriate compensation strategy based on the system components and changeable condition must be configured to handle the characteristics of the internal systems. Since renewable sources generate various fluctuations, the compensation plans for the storage device connected along with the sources should be supported by a precise expectation method. A cooperative strategy involving the sharing of the DC section with environmentally sensitive generators, like photovoltaic system (PVs or waves, demands appropriate ESS compensation solutions, owing to its complexity. An active power-control algorithm with voltage-expectation based on the DC power flow is introduced in this paper and is applied in the designed case studies performed on the electromagnetic transient simulation. DC based multi-generation system is composed by applying tidal generator and super capacitor. To utilize wind energy, an offshore wind–wave generation system was utilized in the verification process.
ADVANTAGES AND DISADVANTAGES OF APPLYING EVOLVED METHODS IN MANAGEMENT ACCOUNTING PRACTICE
Directory of Open Access Journals (Sweden)
SABOU FELICIA
2014-05-01
Full Text Available The evolved methods of management accounting have been developed with the purpose of removing the disadvantages of the classical methods, they are methods adapted to the new market conditions, which provide much more useful cost-related information so that the management of the company is able to take certain strategic decisions. Out of the category of evolved methods, the most used is the one of standard-costs due to the advantages that it presents, being used widely in calculating the production costs in some developed countries. The main advantages of the standard-cost method are: in-advance knowledge of the production costs and the measures that ensure compliance to these; with the help of the deviations calculated from the standard costs, one manages a systematic control over the costs, thus allowing the making of decision in due time, in as far as the elimination of the deviations and the improvement of the activity are concerned and it is a method of analysis, control and cost forecast; Although the advantages of using standards are significant, there are a few disadvantages to the employment of the standard-cost method: sometimes there can appear difficulties in establishing the deviations from the standard costs, the method does not allow an accurate calculation of the fixed costs. As a result of the study, we can observe the fact that the evolved methods of management accounting, as compared to the classical ones, present a series of advantages linked to a better analysis, control, and foreseeing of costs, whereas the main disadvantage is related to the large amount of work necessary for these methods to be applied
ADVANTAGES AND DISADVANTAGES OF APPLYING EVOLVED METHODS IN MANAGEMENT ACCOUNTING PRACTICE
Directory of Open Access Journals (Sweden)
SABOU FELICIA
2014-05-01
Full Text Available The evolved methods of management accounting have been developed with the purpose of removing the disadvantages of the classical methods, they are methods adapted to the new market conditions, which provide much more useful cost-related information so that the management of the company is able to take certain strategic decisions. Out of the category of evolved methods, the most used is the one of standard-costs due to the advantages that it presents, being used widely in calculating the production costs in some developed countries. The main advantages of the standard-cost method are: in-advance knowledge of the production costs and the measures that ensure compliance to these; with the help of the deviations calculated from the standard costs, one manages a systematic control over the costs, thus allowing the making of decision in due time, in as far as the elimination of the deviations and the improvement of the activity are concerned and it is a method of analysis, control and cost forecast; Although the advantages of using standards are significant, there are a few disadvantages to the employment of the standard-cost method: sometimes there can appear difficulties in establishing the deviations from the standard costs, the method does not allow an accurate calculation of the fixed costs. As a result of the study, we can observe the fact that the evolved methods of management accounting, as compared to the classical ones, present a series of advantages linked to a better analysis, control, and foreseeing of costs, whereas the main disadvantage is related to the large amount of work necessary for these methods to be applied.
DC-Compensated Current Transformer †
Ripka, Pavel; Draxler, Karel; Styblíková, Renata
2016-01-01
Instrument current transformers (CTs) measure AC currents. The DC component in the measured current can saturate the transformer and cause gross error. We use fluxgate detection and digital feedback compensation of the DC flux to suppress the overall error to 0.15%. This concept can be used not only for high-end CTs with a nanocrystalline core, but it also works for low-cost CTs with FeSi cores. The method described here allows simultaneous measurements of the DC current component. PMID:26805830
Directory of Open Access Journals (Sweden)
Achmad Abdul Ghoni
2015-12-01
Full Text Available Seiring berjalannya waktu dibutuhkan pengembangan teknologi pada motor penggerak pada kendaraan yang beredar dipasaran. Karena sumber energi fosil merupakan energi yang tidak dapat diperbarui, maka pengembangan kendaraan dengan listrik sebagai sumber energi adalah solusi untuk penghematan energi dimasa depan. Salah satu jenis motor yang tepat untuk digunakan sebagai penggerak kendaraan akan dibahas pada tugas akhir ini, yaitu motor axial flux brushless DC. Pada tugas akhir ini dilakukan pembuatan desain dan analisis simulasi variabel air gap pada motor axial flux brushless DC dengan rating daya output 12 kW, tegangan DC input 400 V, frekuensi 200 Hz, dan kecepatan 2388 rpm. Varasi variabel air gap dilakukan dengan cara membuat jarak air gap pada jari-jari dalam lebih lebar dibandingkan jari-jari luar. Variasi variabel air gap yang diberikan menghasilkan perubahan nilai pada beberapa parameter kelistrikan motor. Dari simulasi yang didapatkan variasi variabel air gap terbaik pada 1,5 mm dengan kompensasi penambahan ketebalan magnet permanen sebesar 5 mm. Hasil dari variabel air gap pada motor axial flux brushless DC adalah rating daya output yang meningkat menjadi 14,5 kW dengan efisiensi 78,8 persen dan core loss sebesar 356,2 W.
Czech Academy of Sciences Publication Activity Database
Chomát, Miroslav; Schreier, Luděk
2005-01-01
Roč. 152, č. 3 (2005), s. 494-500 ISSN 1350-2352 R&D Projects: GA ČR(CZ) GA102/02/0554 Institutional research plan: CEZ:AV0Z20570509 Keywords : DC-link voltage * unbalanced three-phase voltage Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.587, year: 2005
The patent describes a synchronous direct current (dc) power supply which has the power supply input drive synchronized with the pulse repetition...frequency (PRF) of the amplifying or load circuit requiring the dc power for operation. This limits the occurrence of ripple components in the power ... supply output to the spectral positions of the PRF lines, eliminating ripple interference with signal processing in the load. An astable multivibrator is
Liu, Bailing; Zhang, Fumin; Qu, Xinghua; Shi, Xiaojia
2016-02-18
Coordinate transformation plays an indispensable role in industrial measurements, including photogrammetry, geodesy, laser 3-D measurement and robotics. The widely applied methods of coordinate transformation are generally based on solving the equations of point clouds. Despite the high accuracy, this might result in no solution due to the use of ill conditioned matrices. In this paper, a novel coordinate transformation method is proposed, not based on the equation solution but based on the geometric transformation. We construct characteristic lines to represent the coordinate systems. According to the space geometry relation, the characteristic line scan is made to coincide by a series of rotations and translations. The transformation matrix can be obtained using matrix transformation theory. Experiments are designed to compare the proposed method with other methods. The results show that the proposed method has the same high accuracy, but the operation is more convenient and flexible. A multi-sensor combined measurement system is also presented to improve the position accuracy of a robot with the calibration of the robot kinematic parameters. Experimental verification shows that the position accuracy of robot manipulator is improved by 45.8% with the proposed method and robot calibration.
Directory of Open Access Journals (Sweden)
Bailing Liu
2016-02-01
Full Text Available Coordinate transformation plays an indispensable role in industrial measurements, including photogrammetry, geodesy, laser 3-D measurement and robotics. The widely applied methods of coordinate transformation are generally based on solving the equations of point clouds. Despite the high accuracy, this might result in no solution due to the use of ill conditioned matrices. In this paper, a novel coordinate transformation method is proposed, not based on the equation solution but based on the geometric transformation. We construct characteristic lines to represent the coordinate systems. According to the space geometry relation, the characteristic line scan is made to coincide by a series of rotations and translations. The transformation matrix can be obtained using matrix transformation theory. Experiments are designed to compare the proposed method with other methods. The results show that the proposed method has the same high accuracy, but the operation is more convenient and flexible. A multi-sensor combined measurement system is also presented to improve the position accuracy of a robot with the calibration of the robot kinematic parameters. Experimental verification shows that the position accuracy of robot manipulator is improved by 45.8% with the proposed method and robot calibration.
Liu, Bailing; Zhang, Fumin; Qu, Xinghua; Shi, Xiaojia
2016-01-01
Coordinate transformation plays an indispensable role in industrial measurements, including photogrammetry, geodesy, laser 3-D measurement and robotics. The widely applied methods of coordinate transformation are generally based on solving the equations of point clouds. Despite the high accuracy, this might result in no solution due to the use of ill conditioned matrices. In this paper, a novel coordinate transformation method is proposed, not based on the equation solution but based on the geometric transformation. We construct characteristic lines to represent the coordinate systems. According to the space geometry relation, the characteristic line scan is made to coincide by a series of rotations and translations. The transformation matrix can be obtained using matrix transformation theory. Experiments are designed to compare the proposed method with other methods. The results show that the proposed method has the same high accuracy, but the operation is more convenient and flexible. A multi-sensor combined measurement system is also presented to improve the position accuracy of a robot with the calibration of the robot kinematic parameters. Experimental verification shows that the position accuracy of robot manipulator is improved by 45.8% with the proposed method and robot calibration. PMID:26901203
Projector methods applied to numerical integration of the SN transport equation
International Nuclear Information System (INIS)
Hristea, V.; Covaci, St.
2003-01-01
We are developing two methods of integration for the S N transport equation in x - y geometry, methods based on projector technique. By cellularization of the phase space and by choosing a finite basis of orthogonal functions, which characterize the angular flux, the non-selfadjoint transport equation is reduced to a cellular automaton. This automaton is completely described by the transition Matrix T. Within this paper two distinct methods of projection are described. One of them uses the transversal integration technique. As an alternative to this we applied the method of the projectors for the integral S N transport equation. We show that the constant spatial approximation of the integral S N transport equation does not lead to negative fluxes. One of the problems with the projector method, namely the appearance of numerical instability for small intervals is solved by the Pade representation of the elements for Matrix T. Numerical tests here presented compare the numerical performances of the algorithms obtained by the two projection methods. The Pade representation was also taken into account for these two algorithm types. (authors)
Lozano, Lorena; Algar, Ma Jesús; García, Eliseo; González, Iván; Cátedra, Felipe
2017-12-01
An improved ray-tracing method applied to high-frequency techniques such as the Uniform Theory of Diffraction (UTD) is presented. The main goal is to increase the speed of the analysis of complex structures while considering a vast number of observation directions and taking into account multiple bounces. The method is based on a combination of the Angular Z-Buffer (AZB), the Space Volumetric Partitioning (SVP) algorithm and the A∗ heuristic search method to treat multiple bounces. In addition, a Master Point strategy was developed to analyze efficiently a large number of Near-Field points or Far-Field directions. This technique can be applied to electromagnetic radiation problems, scattering analysis, propagation at urban or indoor environments and to the mutual coupling between antennas. Due to its efficiency, its application is suitable to study large antennas radiation patterns and even its interactions with complex environments, including satellites, ships, aircrafts, cities or another complex electrically large bodies. The new technique appears to be extremely efficient at these applications even when considering multiple bounces.
Methodical basis of training of cadets for the military applied heptathlon competitions
Directory of Open Access Journals (Sweden)
R.V. Anatskyi
2017-12-01
Full Text Available The purpose of the research is to develop methodical bases of training of cadets for the military applied heptathlon competitions. Material and methods: Cadets of 2-3 courses at the age of 19-20 years (n=20 participated in researches. Cadets were selected by the best results of exercises performing included into the program of military applied heptathlon competitions (100 m run, 50 m freestyle swimming, Kalashnikov rifle shooting, pull-up, obstacle course, grenade throwing, 3000 m run. Preparation took place on the basis of training center. All trainings were organized and carried out according to the methodical basics: in a week preparation microcycle five days cadets had two trainings a day (on Saturday was one training, on Sunday they had rest. The selected exercises with individual loads were performed, Results : Sport scores demonstrated top results in the performance of 100 m run, 3000 m run and pull-up. The indices of performing exercise "obstacle course" were much lower than expected. Rather low results were demonstrated in swimming and shooting. Conclusions . Results of researches indicate the necessity of quality improvement: cadets’ weapons proficiency; physical readiness to perform the exercises requiring complex demonstration of all physical qualities.
Three new DC-to-DC Single-Switch Converters
Directory of Open Access Journals (Sweden)
Barry W. Williams
2017-06-01
Full Text Available This paper presents a new family of three previously unidentified dc-to-dc converters, buck, boost, and buck-boost voltage-transfer-function topologies, which offer advantageous transformer coupling features and low capacitor dc voltage stressing. The three single-switch, single-diode, converters offer the same features as basic dc-to-dc converters, such as the buck function with continuous output current and the boost function with continuous input current. Converter time-domain simulations and experimental results (including transformer coupling support and extol the dc-to-dc converter concepts and analysis presented.
Brushless DC Motor Control System Design Based on DSP2812
Directory of Open Access Journals (Sweden)
Wei Min
2016-01-01
Full Text Available By comparison various control methods currently for permanent magnet brushless DC motor, on the basis of motor principle analysis, a current smallest and most real-time all-digital rare earth permanent magnet brushless DC motor control system is designed. The high-speed digital signal processor DSP2812 is applied as the main control unit. The fuzzy PID control algorithm is used to control rectifier regulator and speed, which the speed and current is double closed loop in the system. The principle of control system, control strategy and software is analyzed in this paper. The system has some features such as less overshoot, rapid response speed, good performance of anti-jamming, simple structure, high control precision, flexible in changing control policies and so on. Validity of the design is verified by prototype test.
Symanzik's method applied to fractional quantum Hall edge states
Energy Technology Data Exchange (ETDEWEB)
Blasi, A.; Ferraro, D.; Maggiore, N.; Magnoli, N. [Dipartimento di Fisica, Universita di Genova (Italy); LAMIA-INFM-CNR, Genova (Italy); Sassetti, M.
2008-11-15
The method of separability, introduced by Symanzik, is applied in order to describe the effect of a boundary for a fractional quantum Hall liquid in the Laughlin series. An Abelian Chern-Simons theory with plane boundary is considered and the Green functions both in the bulk and on the edge are constructed, following a rigorous, perturbative, quantum field theory treatment. We show that the conserved boundary currents find an explicit interpretation in terms of the continuity equation with the electron density satisfying the Tomonaga-Luttinger commutation relation. (Abstract Copyright [2008], Wiley Periodicals, Inc.)
Method for applying a photoresist layer to a substrate having a preexisting topology
Morales, Alfredo M.; Gonzales, Marcela
2004-01-20
The present invention describes a method for preventing a photoresist layer from delaminating, peeling, away from the surface of a substrate that already contains an etched three dimensional structure such as a hole or a trench. The process comprises establishing a saturated vapor phase of the solvent media used to formulate the photoresist layer, above the surface of the coated substrate as the applied photoresist is heated in order to "cure" or drive off the retained solvent constituent within the layer. By controlling the rate and manner in which solvent is removed from the photoresist layer the layer is stabilized and kept from differentially shrinking and peeling away from the substrate.
Tumino, A.; Spitaleri, C.; Musumarra, A.; Pellegriti, M. G.; Pizzone, R. G.; Rinollo, A.; Romano, S.; Pappalardo, L.; Bonomo, C.; Del Zoppo, A.; Di Pietro, A.; Figuera, P.; La Cognata, M.; Lamia, L.; Cherubini, S.; Rolfs, C.; Typel, S.
2005-12-01
The 7Li(p,α)4He 6Li(d,α)4He and 6Li(p,α)3He reactions was performed and studied in the framework of the Trojan Horse Method applied to the d(7Li,αα)n, 6Li(6Li,αα)4He and d(6Li,α3He)n three-body reactions respectively. Their bare astrophysical S-factors were extracted and from the comparison with the behavior of the screened direct data, an independent estimate of the screening potential was obtained.
Making Design Decisions Visible: Applying the Case-Based Method in Designing Online Instruction
Directory of Open Access Journals (Sweden)
Heng Luo,
2011-01-01
Full Text Available The instructional intervention in this design case is a self-directed online tutorial that applies the case-based method to teach educators how to design and conduct entrepreneurship programs for elementary school students. In this article, the authors describe the major decisions made in each phase of the design and development process, explicate the rationales behind them, and demonstrate their effect on the production of the tutorial. Based on such analysis, the guidelines for designing case-based online instruction are summarized for the design case.
DEFF Research Database (Denmark)
Dragicevic, Tomislav; Lu, Xiaonan; Quintero, Juan Carlos Vasquez
2016-01-01
This paper presents a review of control strategies, stability analysis and stabilization techniques for DC microgrids (MGs). Overall control is systematically classified into local and coordinated control levels according to respective functionalities in each level. As opposed to local control...... strategies to achieve various control objectives are reviewed in the paper. Moreover, properties of DC MG dynamics and stability are discussed. The paper illustrates that tightly regulated point-of-load (POL) converters tend to reduce the stability margins of the system since they introduce negative...... which relies only on local measurements, some line of communication between units needs to be made available in order to achieve coordinated control. Depending on the communication method, three basic coordinated control strategies can be distinguished, i.e. decentralized, centralized and distributed...
DEFF Research Database (Denmark)
Haxthausen, Anne; Yong, Xia
1999-01-01
(parts of) the history of the observables of the system,and then define a satisfaction relation in terms of behaviours. DC has previously been linked together with subsets of other event-based process algebra languages, but using another approach:the event-based languages were given a denotational...... of constraints on the durations of states of the system, i.e. at a high level of abstraction.However, as a state-based logic, it lacks the ability to specifysequential programs and communicating concurrent processes at a concrete level. The Timed RAISE Specification Language (TRSL) [XG99] has this ability.......TRSL is a real-time extension of the RAISE Specification Language (RSL) [Rlg92] which together with its associated method [Rmg95]and tools has shown to be very useful in the industrial development of software systems. Therefore, a promising approach for the development of real-time systemscould be to use DC...
A Review of Auditing Methods Applied to the Content of Controlled Biomedical Terminologies
Zhu, Xinxin; Fan, Jung-Wei; Baorto, David M.; Weng, Chunhua; Cimino, James J.
2012-01-01
Although controlled biomedical terminologies have been with us for centuries, it is only in the last couple of decades that close attention has been paid to the quality of these terminologies. The result of this attention has been the development of auditing methods that apply formal methods to assessing whether terminologies are complete and accurate. We have performed an extensive literature review to identify published descriptions of these methods and have created a framework for characterizing them. The framework considers manual, systematic and heuristic methods that use knowledge (within or external to the terminology) to measure quality factors of different aspects of the terminology content (terms, semantic classification, and semantic relationships). The quality factors examined included concept orientation, consistency, non-redundancy, soundness and comprehensive coverage. We reviewed 130 studies that were retrieved based on keyword search on publications in PubMed, and present our assessment of how they fit into our framework. We also identify which terminologies have been audited with the methods and provide examples to illustrate each part of the framework. PMID:19285571
A Comparison of Parametric and Non-Parametric Methods Applied to a Likert Scale.
Mircioiu, Constantin; Atkinson, Jeffrey
2017-05-10
A trenchant and passionate dispute over the use of parametric versus non-parametric methods for the analysis of Likert scale ordinal data has raged for the past eight decades. The answer is not a simple "yes" or "no" but is related to hypotheses, objectives, risks, and paradigms. In this paper, we took a pragmatic approach. We applied both types of methods to the analysis of actual Likert data on responses from different professional subgroups of European pharmacists regarding competencies for practice. Results obtained show that with "large" (>15) numbers of responses and similar (but clearly not normal) distributions from different subgroups, parametric and non-parametric analyses give in almost all cases the same significant or non-significant results for inter-subgroup comparisons. Parametric methods were more discriminant in the cases of non-similar conclusions. Considering that the largest differences in opinions occurred in the upper part of the 4-point Likert scale (ranks 3 "very important" and 4 "essential"), a "score analysis" based on this part of the data was undertaken. This transformation of the ordinal Likert data into binary scores produced a graphical representation that was visually easier to understand as differences were accentuated. In conclusion, in this case of Likert ordinal data with high response rates, restraining the analysis to non-parametric methods leads to a loss of information. The addition of parametric methods, graphical analysis, analysis of subsets, and transformation of data leads to more in-depth analyses.
Brezina, Tadej; Graser, Anita; Leth, Ulrich
2017-04-01
Space, and in particular public space for movement and leisure, is a valuable and scarce resource, especially in today's growing urban centres. The distribution and absolute amount of urban space—especially the provision of sufficient pedestrian areas, such as sidewalks—is considered crucial for shaping living and mobility options as well as transport choices. Ubiquitous urban data collection and today's IT capabilities offer new possibilities for providing a relation-preserving overview and for keeping track of infrastructure changes. This paper presents three novel methods for estimating representative sidewalk widths and applies them to the official Viennese streetscape surface database. The first two methods use individual pedestrian area polygons and their geometrical representations of minimum circumscribing and maximum inscribing circles to derive a representative width of these individual surfaces. The third method utilizes aggregated pedestrian areas within the buffered street axis and results in a representative width for the corresponding road axis segment. Results are displayed as city-wide means in a 500 by 500 m grid and spatial autocorrelation based on Moran's I is studied. We also compare the results between methods as well as to previous research, existing databases and guideline requirements on sidewalk widths. Finally, we discuss possible applications of these methods for monitoring and regression analysis and suggest future methodological improvements for increased accuracy.
Complex Method Mixed with PSO Applying to Optimization Design of Bridge Crane Girder
Directory of Open Access Journals (Sweden)
He Yan
2017-01-01
Full Text Available In engineer design, basic complex method has not enough global search ability for the nonlinear optimization problem, so it mixed with particle swarm optimization (PSO has been presented in the paper,that is the optimal particle evaluated from fitness function of particle swarm displacement complex vertex in order to realize optimal principle of the largest complex central distance.This method is applied to optimization design problems of box girder of bridge crane with constraint conditions.At first a mathematical model of the girder optimization has been set up,in which box girder cross section area of bridge crane is taken as the objective function, and its four sizes parameters as design variables, girder mechanics performance, manufacturing process, border sizes and so on requirements as constraint conditions. Then complex method mixed with PSO is used to solve optimization design problem of cane box girder from constrained optimization studying approach, and its optimal results have achieved the goal of lightweight design and reducing the crane manufacturing cost . The method is reliable, practical and efficient by the practical engineer calculation and comparative analysis with basic complex method.
Knowledge-Based Trajectory Error Pattern Method Applied to an Active Force Control Scheme
Directory of Open Access Journals (Sweden)
Endra Pitowarno, Musa Mailah, Hishamuddin Jamaluddin
2012-08-01
Full Text Available The active force control (AFC method is known as a robust control scheme that dramatically enhances the performance of a robot arm particularly in compensating the disturbance effects. The main task of the AFC method is to estimate the inertia matrix in the feedback loop to provide the correct (motor torque required to cancel out these disturbances. Several intelligent control schemes have already been introduced to enhance the estimation methods of acquiring the inertia matrix such as those using neural network, iterative learning and fuzzy logic. In this paper, we propose an alternative scheme called Knowledge-Based Trajectory Error Pattern Method (KBTEPM to suppress the trajectory track error of the AFC scheme. The knowledge is developed from the trajectory track error characteristic based on the previous experimental results of the crude approximation method. It produces a unique, new and desirable error pattern when a trajectory command is forced. An experimental study was performed using simulation work on the AFC scheme with KBTEPM applied to a two-planar manipulator in which a set of rule-based algorithm is derived. A number of previous AFC schemes are also reviewed as benchmark. The simulation results show that the AFC-KBTEPM scheme successfully reduces the trajectory track error significantly even in the presence of the introduced disturbances.Key Words: Active force control, estimated inertia matrix, robot arm, trajectory error pattern, knowledge-based.
Efficient alpha particle detection by CR-39 applying 50 Hz-HV electrochemical etching method
International Nuclear Information System (INIS)
Sohrabi, M.; Soltani, Z.
2016-01-01
Alpha particles can be detected by CR-39 by applying either chemical etching (CE), electrochemical etching (ECE), or combined pre-etching and ECE usually through a multi-step HF-HV ECE process at temperatures much higher than room temperature. By applying pre-etching, characteristics responses of fast-neutron-induced recoil tracks in CR-39 by HF-HV ECE versus KOH normality (N) have shown two high-sensitivity peaks around 5–6 and 15–16 N and a large-diameter peak with a minimum sensitivity around 10–11 N at 25°C. On the other hand, 50 Hz-HV ECE method recently advanced in our laboratory detects alpha particles with high efficiency and broad registration energy range with small ECE tracks in polycarbonate (PC) detectors. By taking advantage of the CR-39 sensitivity to alpha particles, efficacy of 50 Hz-HV ECE method and CR-39 exotic responses under different KOH normalities, detection characteristics of 0.8 MeV alpha particle tracks were studied in 500 μm CR-39 for different fluences, ECE duration and KOH normality. Alpha registration efficiency increased as ECE duration increased to 90 ± 2% after 6–8 h beyond which plateaus are reached. Alpha track density versus fluence is linear up to 10 6 tracks cm −2 . The efficiency and mean track diameter versus alpha fluence up to 10 6 alphas cm −2 decrease as the fluence increases. Background track density and minimum detection limit are linear functions of ECE duration and increase as normality increases. The CR-39 processed for the first time in this study by 50 Hz-HV ECE method proved to provide a simple, efficient and practical alpha detection method at room temperature. - Highlights: • Alpha particles of 0.8 MeV were detected in CR-39 by 50 Hz-HV ECE method. • Efficiency/track diameter was studied vs fluence and time for 3 KOH normality. • Background track density and minimum detection limit vs duration were studied. • A new simple, efficient and low-cost alpha detection method
dc illusion and its experimental verification
Liu, Min; Lei Mei, Zhong; Ma, Xiang; Cui, Tie Jun
2012-07-01
Based on the transformation optics method, we propose a dc illusion device, which can transform a metallic object into a magnified dielectric object using anisotropic conducting materials. Utilizing the analogy between electric conductivities and resistor networks, we design and fabricate the device using metal film resistors. The practical measurement data agree very well with simulation results. The proposed dc illusion device is easy to process and measure, and thus has potential applications in various sectors.
A METHOD FOR PREPARING A SUBSTRATE BY APPLYING A SAMPLE TO BE ANALYSED
DEFF Research Database (Denmark)
2017-01-01
The invention relates to a method for preparing a substrate (105a) comprising a sample reception area (110) and a sensing area (111). The method comprises the steps of: 1) applying a sample on the sample reception area; 2) rotating the substrate around a predetermined axis; 3) during rotation......, at least part of the liquid travels from the sample reception area to the sensing area due to capillary forces acting between the liquid and the substrate; and 4) removing the wave of particles and liquid formed at one end of the substrate. The sensing area is closer to the predetermined axis than...... the sample reception area. The sample comprises a liquid part and particles suspended therein....
Super-convergence of Discontinuous Galerkin Method Applied to the Navier-Stokes Equations
Atkins, Harold L.
2009-01-01
The practical benefits of the hyper-accuracy properties of the discontinuous Galerkin method are examined. In particular, we demonstrate that some flow attributes exhibit super-convergence even in the absence of any post-processing technique. Theoretical analysis suggest that flow features that are dominated by global propagation speeds and decay or growth rates should be super-convergent. Several discrete forms of the discontinuous Galerkin method are applied to the simulation of unsteady viscous flow over a two-dimensional cylinder. Convergence of the period of the naturally occurring oscillation is examined and shown to converge at 2p+1, where p is the polynomial degree of the discontinuous Galerkin basis. Comparisons are made between the different discretizations and with theoretical analysis.
Balasoiu, Maria; Kuklin, Alexander
2012-03-01
Separate determination of the nuclear and magnetic contributions to the scattering intensity by means of a contrast variation method applied in a small angle neutron scattering experiment of nonpolarized neutrons in ferrofluids in early 90 's at the MURN instrument is reviewed. The nuclear scattering contribution gives the features of the colloidal particle dimensions, surfactant shell structure and the solvent degree penetration to the macromolecular layer. The magnetic scattering part is compatible to the models where is supposed that the particle surface has a nonmagnetic layer. Details on experimental "Grabcev method" in obtaining separate nuclear and magnetic contributions to the small angle neutron scattering intensity of unpolarized neutrons are emphasized for the case of a high quality ultrastabile benzene-based ferrofluid with magnetite nanoparticles.
International Nuclear Information System (INIS)
Balasoiu, Maria; Kuklin, Alexander
2012-01-01
Separate determination of the nuclear and magnetic contributions to the scattering intensity by means of a contrast variation method applied in a small angle neutron scattering experiment of nonpolarized neutrons in ferrofluids in early 90 's at the MURN instrument is reviewed. The nuclear scattering contribution gives the features of the colloidal particle dimensions, surfactant shell structure and the solvent degree penetration to the macromolecular layer. The magnetic scattering part is compatible to the models where is supposed that the particle surface has a nonmagnetic layer. Details on experimental 'Grabcev method' in obtaining separate nuclear and magnetic contributions to the small angle neutron scattering intensity of unpolarized neutrons are emphasized for the case of a high quality ultrastabile benzene-based ferrofluid with magnetite nanoparticles.
Infrared thermography inspection methods applied to the target elements of W7-X divertor
Energy Technology Data Exchange (ETDEWEB)
Missirlian, M. [Association Euratom-CEA, CEA/DSM/DRFC, CEA/Cadarache, F-13108 Saint Paul Lez Durance (France)], E-mail: marc.missirlian@cea.fr; Traxler, H. [PLANSEE SE, Technology Center, A-6600 Reutte (Austria); Boscary, J. [Max-Planck-Institut fuer Plasmaphysik, Euratom Association, Boltzmannstr. 2, D-85748 Garching (Germany); Durocher, A.; Escourbiac, F.; Schlosser, J. [Association Euratom-CEA, CEA/DSM/DRFC, CEA/Cadarache, F-13108 Saint Paul Lez Durance (France); Schedler, B.; Schuler, P. [PLANSEE SE, Technology Center, A-6600 Reutte (Austria)
2007-10-15
The non-destructive examination (NDE) method is one of the key issues in developing highly loaded plasma-facing components (PFCs) for a next generation fusion devices such as W7-X and ITER. The most critical step is certainly the fabrication and the examination of the bond between the armour and the heat sink. Two inspection systems based on the infrared thermography methods, namely, the transient thermography (SATIR-CEA) and the pulsed thermography (ARGUS-PLANSEE), are being developed and have been applied to the pre-series of target elements of the W7-X divertor. Results obtained from qualification experiences performed on target elements with artificial calibrated defects allowed to demonstrate the capability of the two techniques and raised the efficiency of inspection to a level which is appropriate for industrial application.
Infrared thermography inspection methods applied to the target elements of W7-X divertor
International Nuclear Information System (INIS)
Missirlian, M.; Traxler, H.; Boscary, J.; Durocher, A.; Escourbiac, F.; Schlosser, J.; Schedler, B.; Schuler, P.
2007-01-01
The non-destructive examination (NDE) method is one of the key issues in developing highly loaded plasma-facing components (PFCs) for a next generation fusion devices such as W7-X and ITER. The most critical step is certainly the fabrication and the examination of the bond between the armour and the heat sink. Two inspection systems based on the infrared thermography methods, namely, the transient thermography (SATIR-CEA) and the pulsed thermography (ARGUS-PLANSEE), are being developed and have been applied to the pre-series of target elements of the W7-X divertor. Results obtained from qualification experiences performed on target elements with artificial calibrated defects allowed to demonstrate the capability of the two techniques and raised the efficiency of inspection to a level which is appropriate for industrial application
Data Analytics of Mobile Serious Games: Applying Bayesian Data Analysis Methods
Directory of Open Access Journals (Sweden)
Heide Lukosch
2018-03-01
Full Text Available Traditional teaching methods in the field of resuscitation training show some limitations, while teaching the right actions in critical situations could increase the number of people saved after a cardiac arrest. For our study, we developed a mobile game to support the transfer of theoretical knowledge on resuscitation. The game has been tested at three schools of further education. A number of data has been collected from 171 players. To analyze this large data set from different sources and quality, different types of data modeling and analyses had to be applied. This approach showed its usefulness in analyzing the large set of data from different sources. It revealed some interesting findings, such as that female players outperformed the male ones, and that the game fostering informal, self-directed is equally efficient as the traditional formal learning method.
Digital DC beam current measurement on SSRF storage ring
International Nuclear Information System (INIS)
Xiong Liang; Yin Chongxian; Liu Ming; Chen Jianfeng
2011-01-01
Both DC current transformer (DCCT) and integrating current transformer (ICT) can be used in DC beam current measurement. The ICT has strong capability of resisting electromagnetic interference, but its measurement accuracy cannot satisfy the DC beam current measurement requirement when using traditional high speed A/D. With high resolution A/D and equivalent sampling system, DC beam current measuring system based on ICT can reach high accuracy compared with DCCT system. In this paper, the ICT-based DC beam current measurement, equivalent sampling method and testing results at Shanghai Synchrotron Radiation Facility(SSRF) is described. (authors)
Su, Hailin; Li, Hengde; Wang, Shi; Wang, Yangfan; Bao, Zhenmin
2017-02-01
Genomic selection is more and more popular in animal and plant breeding industries all around the world, as it can be applied early in life without impacting selection candidates. The objective of this study was to bring the advantages of genomic selection to scallop breeding. Two different genomic selection tools MixP and gsbay were applied on genomic evaluation of simulated data and Zhikong scallop ( Chlamys farreri) field data. The data were compared with genomic best linear unbiased prediction (GBLUP) method which has been applied widely. Our results showed that both MixP and gsbay could accurately estimate single-nucleotide polymorphism (SNP) marker effects, and thereby could be applied for the analysis of genomic estimated breeding values (GEBV). In simulated data from different scenarios, the accuracy of GEBV acquired was ranged from 0.20 to 0.78 by MixP; it was ranged from 0.21 to 0.67 by gsbay; and it was ranged from 0.21 to 0.61 by GBLUP. Estimations made by MixP and gsbay were expected to be more reliable than those estimated by GBLUP. Predictions made by gsbay were more robust, while with MixP the computation is much faster, especially in dealing with large-scale data. These results suggested that both algorithms implemented by MixP and gsbay are feasible to carry out genomic selection in scallop breeding, and more genotype data will be necessary to produce genomic estimated breeding values with a higher accuracy for the industry.
DEFF Research Database (Denmark)
Meng, Lexuan; Dragicevic, Tomislav; Quintero, Juan Carlos Vasquez
2015-01-01
Droop control by means of virtual resistance (VR) control loops can be applied to paralleled dc-dc converters for achieving autonomous equal power sharing. However, equal power sharing does not guarantee an efficient operation of the whole system. In order to achieve higher efficiency and lower...... energy losses, this paper proposes a tertiary control level including an optimization method for achieving efficient operation. As the efficiency of each converter changes with the output power, VR values are set as decision variables for modifying the power sharing ratio among converters. Genetic...... algorithm is used in searching for a global efficiency optimum. In addition, a secondary control level is added to regulate the output voltage drooped by the VRs. However, system dynamics is affected when shifting up/down the VR references. Therefore, a secondary control for system damping is proposed...
Sills, Erin O.; Herrera, Diego; Kirkpatrick, A. Justin; Brandão, Amintas; Dickson, Rebecca; Hall, Simon; Pattanayak, Subhrendu; Shoch, David; Vedoveto, Mariana; Young, Luisa; Pfaff, Alexander
2015-01-01
Quasi-experimental methods increasingly are used to evaluate the impacts of conservation interventions by generating credible estimates of counterfactual baselines. These methods generally require large samples for statistical comparisons, presenting a challenge for evaluating innovative policies implemented within a few pioneering jurisdictions. Single jurisdictions often are studied using comparative methods, which rely on analysts’ selection of best case comparisons. The synthetic control method (SCM) offers one systematic and transparent way to select cases for comparison, from a sizeable pool, by focusing upon similarity in outcomes before the intervention. We explain SCM, then apply it to one local initiative to limit deforestation in the Brazilian Amazon. The municipality of Paragominas launched a multi-pronged local initiative in 2008 to maintain low deforestation while restoring economic production. This was a response to having been placed, due to high deforestation, on a federal “blacklist” that increased enforcement of forest regulations and restricted access to credit and output markets. The local initiative included mapping and monitoring of rural land plus promotion of economic alternatives compatible with low deforestation. The key motivation for the program may have been to reduce the costs of blacklisting. However its stated purpose was to limit deforestation, and thus we apply SCM to estimate what deforestation would have been in a (counterfactual) scenario of no local initiative. We obtain a plausible estimate, in that deforestation patterns before the intervention were similar in Paragominas and the synthetic control, which suggests that after several years, the initiative did lower deforestation (significantly below the synthetic control in 2012). This demonstrates that SCM can yield helpful land-use counterfactuals for single units, with opportunities to integrate local and expert knowledge and to test innovations and permutations on
Sills, Erin O; Herrera, Diego; Kirkpatrick, A Justin; Brandão, Amintas; Dickson, Rebecca; Hall, Simon; Pattanayak, Subhrendu; Shoch, David; Vedoveto, Mariana; Young, Luisa; Pfaff, Alexander
2015-01-01
Quasi-experimental methods increasingly are used to evaluate the impacts of conservation interventions by generating credible estimates of counterfactual baselines. These methods generally require large samples for statistical comparisons, presenting a challenge for evaluating innovative policies implemented within a few pioneering jurisdictions. Single jurisdictions often are studied using comparative methods, which rely on analysts' selection of best case comparisons. The synthetic control method (SCM) offers one systematic and transparent way to select cases for comparison, from a sizeable pool, by focusing upon similarity in outcomes before the intervention. We explain SCM, then apply it to one local initiative to limit deforestation in the Brazilian Amazon. The municipality of Paragominas launched a multi-pronged local initiative in 2008 to maintain low deforestation while restoring economic production. This was a response to having been placed, due to high deforestation, on a federal "blacklist" that increased enforcement of forest regulations and restricted access to credit and output markets. The local initiative included mapping and monitoring of rural land plus promotion of economic alternatives compatible with low deforestation. The key motivation for the program may have been to reduce the costs of blacklisting. However its stated purpose was to limit deforestation, and thus we apply SCM to estimate what deforestation would have been in a (counterfactual) scenario of no local initiative. We obtain a plausible estimate, in that deforestation patterns before the intervention were similar in Paragominas and the synthetic control, which suggests that after several years, the initiative did lower deforestation (significantly below the synthetic control in 2012). This demonstrates that SCM can yield helpful land-use counterfactuals for single units, with opportunities to integrate local and expert knowledge and to test innovations and permutations on policies
Applying Mathematical Optimization Methods to an ACT-R Instance-Based Learning Model.
Directory of Open Access Journals (Sweden)
Nadia Said
Full Text Available Computational models of cognition provide an interface to connect advanced mathematical tools and methods to empirically supported theories of behavior in psychology, cognitive science, and neuroscience. In this article, we consider a computational model of instance-based learning, implemented in the ACT-R cognitive architecture. We propose an approach for obtaining mathematical reformulations of such cognitive models that improve their computational tractability. For the well-established Sugar Factory dynamic decision making task, we conduct a simulation study to analyze central model parameters. We show how mathematical optimization techniques can be applied to efficiently identify optimal parameter values with respect to different optimization goals. Beyond these methodological contributions, our analysis reveals the sensitivity of this particular task with respect to initial settings and yields new insights into how average human performance deviates from potential optimal performance. We conclude by discussing possible extensions of our approach as well as future steps towards applying more powerful derivative-based optimization methods.
Labile soil phosphorus as influenced by methods of applying radioactive phosphorus
International Nuclear Information System (INIS)
Selvaratnam, V.V.; Andersen, A.J.; Thomsen, J.D.; Gissel-Nielsen, G.
1980-03-01
The influence of different methods of applying radioactive phosphorus on the E- and L-values was studied in four foil types using barley, buckwheat, and rye grass for the L-value determination. The four soils differed greatly in their E- and L-values. The experiment was carried out both with and without carrier-P. The presence of carrier-P had no influence on the E-values, while carrier-P in some cases gave a lower L-value. Both E- and L-values dependent on the method of application. When the 32 P was applied on a small soil or sand sample and dried before mixing with the total amount of soil, the E-values were higher than at direct application most likely because of a stronger fixation to the soil/sand particles. This was not the case for the L-values that are based on a much longer equilibrium time. On the contrary, the direct application of the 32 p-solution to the whole amount of soil gave higher L-values of a non-homogeneous distribution of the 32 p in the soil. (author)
Analysis of coupled neutron-gamma radiations, applied to shieldings in multigroup albedo method
International Nuclear Information System (INIS)
Dunley, Leonardo Souza
2002-01-01
The principal mathematical tools frequently available for calculations in Nuclear Engineering, including coupled neutron-gamma radiations shielding problems, involve the full Transport Theory or the Monte Carlo techniques. The Multigroup Albedo Method applied to shieldings is characterized by following the radiations through distinct layers of materials, allowing the determination of the neutron and gamma fractions reflected from, transmitted through and absorbed in the irradiated media when a neutronic stream hits the first layer of material, independently of flux calculations. Then, the method is a complementary tool of great didactic value due to its clarity and simplicity in solving neutron and/or gamma shielding problems. The outstanding results achieved in previous works motivated the elaboration and the development of this study that is presented in this dissertation. The radiation balance resulting from the incidence of a neutronic stream into a shielding composed by 'm' non-multiplying slab layers for neutrons was determined by the Albedo method, considering 'n' energy groups for neutrons and 'g' energy groups for gammas. It was taken into account there is no upscattering of neutrons and gammas. However, it was considered that neutrons from any energy groups are able to produce gammas of all energy groups. The ANISN code, for an angular quadrature order S 2 , was used as a standard for comparison of the results obtained by the Albedo method. So, it was necessary to choose an identical system configuration, both for ANISN and Albedo methods. This configuration was six neutron energy groups and eight gamma energy groups, using three slab layers (iron aluminum - manganese). The excellent results expressed in comparative tables show great agreement between the values determined by the deterministic code adopted as standard and, the values determined by the computational program created using the Albedo method and the algorithm developed for coupled neutron
Raies, Arwa B.
2017-12-05
One goal of toxicity testing, among others, is identifying harmful effects of chemicals. Given the high demand for toxicity tests, it is necessary to conduct these tests for multiple toxicity endpoints for the same compound. Current computational toxicology methods aim at developing models mainly to predict a single toxicity endpoint. When chemicals cause several toxicity effects, one model is generated to predict toxicity for each endpoint, which can be labor and computationally intensive when the number of toxicity endpoints is large. Additionally, this approach does not take into consideration possible correlation between the endpoints. Therefore, there has been a recent shift in computational toxicity studies toward generating predictive models able to predict several toxicity endpoints by utilizing correlations between these endpoints. Applying such correlations jointly with compounds\\' features may improve model\\'s performance and reduce the number of required models. This can be achieved through multi-label classification methods. These methods have not undergone comprehensive benchmarking in the domain of predictive toxicology. Therefore, we performed extensive benchmarking and analysis of over 19,000 multi-label classification models generated using combinations of the state-of-the-art methods. The methods have been evaluated from different perspectives using various metrics to assess their effectiveness. We were able to illustrate variability in the performance of the methods under several conditions. This review will help researchers to select the most suitable method for the problem at hand and provide a baseline for evaluating new approaches. Based on this analysis, we provided recommendations for potential future directions in this area.
2010-04-21
... Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F... (AD) for certain Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC- 10A and KDC-10), DC-10-40, DC-10-40F, MD-10-10F, MD-10-30F, MD-11, and MD-11F airplanes. This proposed AD would require...
2010-05-04
... Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F.... ACTION: Final rule. SUMMARY: We are adopting a new airworthiness directive (AD) for certain Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F, MD-10-10F, MD...
2010-10-01
... Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F.... ACTION: Final rule. SUMMARY: We are adopting a new airworthiness directive (AD) for certain Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F, MD-10-10F, MD...
Bociaga, Dorota; Sobczyk-Guzenda, Anna; Szymanski, Witold; Jedrzejczak, Anna; Jastrzebska, Aleksandra; Olejnik, Anna; Jastrzebski, Krzysztof
2017-09-01
In this study silicon doped diamond-like carbon (Si-DLC) coatings were synthesized on two substrates: silicon and AISI 316LVM stainless steel using a multi-target DC-RF magnetron sputtering method. The Si content in the films ranged between 4 and 16 at.%, and was controlled by the electrical power applied in RF regime to Si cathode target. The character of the chemical bonds was revealed by FTIR analysis. With the addition of silicon the hydroxyl absorption (band in the range of 3200-3600 cm-1) increased what suggests more hydrophilic character of the coating. There were also observed significant changes in bonding of Si atoms. For low content of dopant, Si-O-Si bond system is predominant, while for the highest content of silicon there is an evidence of the shift to Si-C bonds in close proximity to methyl groups. The Raman spectroscopy revealed that the G peak position is shifted to a lower wavenumber and the ID/IG ratio decreased with increasing Si content, which indicates an increase in the C-sp3 content. Regardless of the coatings' composition, the improvement of hardness in comparison to pure substrate material (AISI 316 LVM) was observed. Although the reduction of the level of hardness from the level of 10.8 GPa for pure DLC to about 9.4 GPa for the silicon doped coatings was observed, the concomitant improvement of films adhesion with higher amount of Si was revealed. Although incorporation of the dopant to DLC coatings increases the number of E. coli cells which adhered to the examined surfaces, the microbial colonisation remains on the level of substrate material. The presented results prove the potential of Si-DLC coatings in biomedical applications from the point of view of their mechanical properties.
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.
The Cn method applied to problems with an anisotropic diffusion law
International Nuclear Information System (INIS)
Grandjean, P.M.
A 2-dimensional Cn calculation has been applied to homogeneous media subjected to the Rayleigh impact law. Results obtained with collision probabilities and Chandrasekhar calculations are compared to those from Cn method. Introducing in the expression of the transport equation, an expansion truncated on a polynomial basis for the outgoing angular flux (or possibly entrance flux) gives two Cn systems of algebraic linear equations for the expansion coefficients. The matrix elements of these equations are the moments of the Green function in infinite medium. The search for the Green function is effected through the Fourier transformation of the integrodifferential equation and its moments are derived from their Fourier transforms through a numerical integration in the complex plane. The method has been used for calculating the albedo in semi-infinite media, the extrapolation length of the Milne problem, and the albedo and transmission factor of a slab (a concise study of convergence is presented). A system of integro-differential equations bearing on the moments of the angular flux inside the medium has been derived, for the collision probability method. It is numerically solved with approximately the bulk flux by step functions. The albedo in semi-infinite medium has also been computed through the semi-analytical Chandrasekhar method. In the latter, the outgoing flux is expressed as a function of the entrance flux by means of a integral whose kernel is numerically derived [fr
International Nuclear Information System (INIS)
Huh, Jae Sung; Kwak, Byung Man
2011-01-01
Robust optimization or reliability-based design optimization are some of the methodologies that are employed to take into account the uncertainties of a system at the design stage. For applying such methodologies to solve industrial problems, accurate and efficient methods for estimating statistical moments and failure probability are required, and further, the results of sensitivity analysis, which is needed for searching direction during the optimization process, should also be accurate. The aim of this study is to employ the function approximation moment method into the sensitivity analysis formulation, which is expressed as an integral form, to verify the accuracy of the sensitivity results, and to solve a typical problem of reliability-based design optimization. These results are compared with those of other moment methods, and the feasibility of the function approximation moment method is verified. The sensitivity analysis formula with integral form is the efficient formulation for evaluating sensitivity because any additional function calculation is not needed provided the failure probability or statistical moments are calculated
Directory of Open Access Journals (Sweden)
V. I. Freyman
2015-11-01
Full Text Available Subject of Research.Representation features of education results for competence-based educational programs are analyzed. Solution importance of decoding and proficiency estimation for elements and components of discipline parts of competences is shown. The purpose and objectives of research are formulated. Methods. The paper deals with methods of mathematical logic, Boolean algebra, and parametrical analysis of complex diagnostic test results, that controls proficiency of some discipline competence elements. Results. The method of logical conditions analysis is created. It will give the possibility to formulate logical conditions for proficiency determination of each discipline competence element, controlled by complex diagnostic test. Normalized test result is divided into noncrossing zones; a logical condition about controlled elements proficiency is formulated for each of them. Summarized characteristics for test result zones are imposed. An example of logical conditions forming for diagnostic test with preset features is provided. Practical Relevance. The proposed method of logical conditions analysis is applied in the decoding algorithm of proficiency test diagnosis for discipline competence elements. It will give the possibility to automate the search procedure for elements with insufficient proficiency, and is also usable for estimation of education results of a discipline or a component of competence-based educational program.
An IMU-to-Body Alignment Method Applied to Human Gait Analysis
Directory of Open Access Journals (Sweden)
Laura Susana Vargas-Valencia
2016-12-01
Full Text Available This paper presents a novel calibration procedure as a simple, yet powerful, method to place and align inertial sensors with body segments. The calibration can be easily replicated without the need of any additional tools. The proposed method is validated in three different applications: a computer mathematical simulation; a simplified joint composed of two semi-spheres interconnected by a universal goniometer; and a real gait test with five able-bodied subjects. Simulation results demonstrate that, after the calibration method is applied, the joint angles are correctly measured independently of previous sensor placement on the joint, thus validating the proposed procedure. In the cases of a simplified joint and a real gait test with human volunteers, the method also performs correctly, although secondary plane errors appear when compared with the simulation results. We believe that such errors are caused by limitations of the current inertial measurement unit (IMU technology and fusion algorithms. In conclusion, the presented calibration procedure is an interesting option to solve the alignment problem when using IMUs for gait analysis.
An IMU-to-Body Alignment Method Applied to Human Gait Analysis.
Vargas-Valencia, Laura Susana; Elias, Arlindo; Rocon, Eduardo; Bastos-Filho, Teodiano; Frizera, Anselmo
2016-12-10
This paper presents a novel calibration procedure as a simple, yet powerful, method to place and align inertial sensors with body segments. The calibration can be easily replicated without the need of any additional tools. The proposed method is validated in three different applications: a computer mathematical simulation; a simplified joint composed of two semi-spheres interconnected by a universal goniometer; and a real gait test with five able-bodied subjects. Simulation results demonstrate that, after the calibration method is applied, the joint angles are correctly measured independently of previous sensor placement on the joint, thus validating the proposed procedure. In the cases of a simplified joint and a real gait test with human volunteers, the method also performs correctly, although secondary plane errors appear when compared with the simulation results. We believe that such errors are caused by limitations of the current inertial measurement unit (IMU) technology and fusion algorithms. In conclusion, the presented calibration procedure is an interesting option to solve the alignment problem when using IMUs for gait analysis.
Energy Technology Data Exchange (ETDEWEB)
Vesisenaho, T. [VTT Energy, Jyvaeskylae (Finland); Liukkonen, S. [VTT Manufacturing Technology, Espoo (Finland)
1997-12-01
The objective of this project is to apply whole-tree harvesting method to Finnish timber harvesting conditions in order to lower the harvesting costs of energy wood and timber in spruce-dominant final cuttings. In Finnish conditions timber harvesting is normally based on the log-length method. Because of small landings and the high level of thinning cuttings, whole-tree skidding methods cannot be utilised extensively. The share of stands which could be harvested with whole-tree skidding method showed up to be about 10 % of the total harvesting amount of 50 mill. m{sup 3}. The corresponding harvesting potential of energy wood is 0,25 Mtoe. The aim of the structural measurements made in this project was to get information about the effect of different hauling methods into the structural response of the tractor, and thus reveal the possible special requirements that the new whole-tree skidding places forest tractor design. Altogether 7 strain gauge based sensors were mounted into the rear frame structures and drive shafts of the forest tractor. Five strain gauges measured local strains in some critical details and two sensors measured the torque moments of the front and rear bogie drive shafts. Also the revolution speed of the rear drive shaft was recorded. Signal time histories, maximum peaks, Time at Level distributions and Rainflow distributions were gathered in different hauling modes. From these, maximum values, average stress levels and fatigue life estimates were calculated for each mode, and a comparison of the different methods from the structural point of view was performed
Directory of Open Access Journals (Sweden)
P. Ye. Mykhalichenko
2009-10-01
Full Text Available In the article a new procedure of choice of minimum current jump for action of fast-acting switches of 3.3 kV DC traction substations intended for the use in the microprocessor protection system of feeders is described. This procedure is more perfect than existing one on the current increment and uses the results of mathematical simulation of the traction electric supply system.
Brucellosis Prevention Program: Applying “Child to Family Health Education” Method
Directory of Open Access Journals (Sweden)
H. Allahverdipour
2010-04-01
Full Text Available Introduction & Objective: Pupils have efficient potential to increase community awareness and promoting community health through participating in the health education programs. Child to family health education program is one of the communicative strategies that was applied in this field trial study. Because of high prevalence of Brucellosis in Hamadan province, Iran, the aim of this study was promoting families’ knowledge and preventive behaviors about Brucellosis in the rural areas by using child to family health education method.Materials & Methods: In this nonequivalent control group design study three rural schools were chosen (one as intervention and two others as control. At first knowledge and behavior of families about Brucellosis were determined using a designed questionnaire. Then the families were educated through “child to family” procedure. At this stage the students gained information. Then they were instructed to teach their parents what they had learned. After 3 months following the last session of education, the level of knowledge and behavior changes of the families about Brucellosis were determined and analyzed by paired t-test.Results: The results showed significant improvement in the knowledge of the mothers. The knowledge of the mothers about the signs of Brucellosis disease in human increased from 1.81 to 3.79 ( t:-21.64 , sig:0.000 , and also the knowledge on the signs of Brucellosis in animals increased from 1.48 to 2.82 ( t:-10.60 , sig:0.000. Conclusion: Child to family health education program is one of the effective and available methods, which would be useful and effective in most communities, and also Students potential would be effective for applying in the health promotion programs.
Xamán, J.; Zavala-Guillén, I.; Hernández-López, I.; Uriarte-Flores, J.; Hernández-Pérez, I.; Macías-Melo, E. V.; Aguilar-Castro, K. M.
2018-03-01
In this paper, we evaluated the convergence rate (CPU time) of a new mathematical formulation for the numerical solution of the radiative transfer equation (RTE) with several High-Order (HO) and High-Resolution (HR) schemes. In computational fluid dynamics, this procedure is known as the Normalized Weighting-Factor (NWF) method and it is adopted here. The NWF method is used to incorporate the high-order resolution schemes in the discretized RTE. The NWF method is compared, in terms of computer time needed to obtain a converged solution, with the widely used deferred-correction (DC) technique for the calculations of a two-dimensional cavity with emitting-absorbing-scattering gray media using the discrete ordinates method. Six parameters, viz. the grid size, the order of quadrature, the absorption coefficient, the emissivity of the boundary surface, the under-relaxation factor, and the scattering albedo are considered to evaluate ten schemes. The results showed that using the DC method, in general, the scheme that had the lowest CPU time is the SOU. In contrast, with the results of theDC procedure the CPU time for DIAMOND and QUICK schemes using the NWF method is shown to be, between the 3.8 and 23.1% faster and 12.6 and 56.1% faster, respectively. However, the other schemes are more time consuming when theNWFis used instead of the DC method. Additionally, a second test case was presented and the results showed that depending on the problem under consideration, the NWF procedure may be computationally faster or slower that the DC method. As an example, the CPU time for QUICK and SMART schemes are 61.8 and 203.7%, respectively, slower when the NWF formulation is used for the second test case. Finally, future researches to explore the computational cost of the NWF method in more complex problems are required.
International Nuclear Information System (INIS)
Yiin, L.-M.; Lu, S.-E.; Sannoh, Sulaiman; Lim, B.S.; Rhoads, G.G.
2004-01-01
We conducted a cleaning trial in 40 northern New Jersey homes where home renovation and remodeling (R and R) activities were undertaken. Two cleaning protocols were used in the study: a specific method recommended by the US Department of Housing and Urban Development (HUD), in the 1995 'Guidelines for the Evaluation and Control of Lead-Based Paint Hazards in Housing', using a high-efficiency particulate air (HEPA)-filtered vacuum cleaner and a tri-sodium phosphate solution (TSP); and an alternative method using a household vacuum cleaner and a household detergent. Eligible homes were built before the 1970s with potential lead-based paint and had recent R and R activities without thorough cleaning. The two cleaning protocols were randomly assigned to the participants' homes and followed the HUD-recommended three-step procedure: vacuuming, wet washing, and repeat vacuuming. Wipe sampling was conducted on floor surfaces or windowsills before and after cleaning to evaluate the efficacy. All floor and windowsill data indicated that both methods (TSP/HEPA and non-TSP/non-HEPA) were effective in reducing lead loading on the surfaces (P<0.001). When cleaning was applied to surfaces with initial lead loading above the clearance standards, the reductions were even greater, above 95% for either cleaning method. The mixed-effect model analysis showed no significant difference between the two methods. Baseline lead loading was found to be associated with lead loading reduction significantly on floors (P<0.001) and marginally on windowsills (P=0.077). Such relations were different between the two cleaning methods significantly on floors (P<0.001) and marginally on windowsills (P=0.066), with the TSP/HEPA method being favored for higher baseline levels and the non-TSP/non-HEPA method for lower baseline levels. For the 10 homes with lead abatement, almost all post-cleaning lead loadings were below the standards using either cleaning method. Based on our results, we recommend that
Method for pulse to pulse dose reproducibility applied to electron linear accelerators
International Nuclear Information System (INIS)
Ighigeanu, D.; Martin, D.; Oproiu, C.; Cirstea, E.; Craciun, G.
2002-01-01
An original method for obtaining programmed beam single shots and pulse trains with programmed pulse number, pulse repetition frequency, pulse duration and pulse dose is presented. It is particularly useful for automatic control of absorbed dose rate level, irradiation process control as well as in pulse radiolysis studies, single pulse dose measurement or for research experiments where pulse-to-pulse dose reproducibility is required. This method is applied to the electron linear accelerators, ALIN-10 of 6.23 MeV and 82 W and ALID-7, of 5.5 MeV and 670 W, built in NILPRP. In order to implement this method, the accelerator triggering system (ATS) consists of two branches: the gun branch and the magnetron branch. ATS, which synchronizes all the system units, delivers trigger pulses at a programmed repetition rate (up to 250 pulses/s) to the gun (80 kV, 10 A and 4 ms) and magnetron (45 kV, 100 A, and 4 ms).The accelerated electron beam existence is determined by the electron gun and magnetron pulses overlapping. The method consists in controlling the overlapping of pulses in order to deliver the beam in the desired sequence. This control is implemented by a discrete pulse position modulation of gun and/or magnetron pulses. The instabilities of the gun and magnetron transient regimes are avoided by operating the accelerator with no accelerated beam for a certain time. At the operator 'beam start' command, the ATS controls electron gun and magnetron pulses overlapping and the linac beam is generated. The pulse-to-pulse absorbed dose variation is thus considerably reduced. Programmed absorbed dose, irradiation time, beam pulse number or other external events may interrupt the coincidence between the gun and magnetron pulses. Slow absorbed dose variation is compensated by the control of the pulse duration and repetition frequency. Two methods are reported in the electron linear accelerators' development for obtaining the pulse to pulse dose reproducibility: the method
Design and Testing of Boost Type DC/DC Converter for DC Motor Control Applications
Samman, Faizal Arya; Akil, Yusri Syam; Noor, Nirwan A.
2017-01-01
in The Proceeding of The 2nd International Symposium on Smart Material and Mechatronics 2015 This paper presents the design and testing of a boost type DC/DC converter circuit, which can be used for DC motor control applications. The Boost converter is designed using DC chopper and DC chopper cascade configurations. The experimental setup was made by connecting the boost converter circuit with four types of DC motor, i.e. self-excited DC motor shunt, series, compound and separately exci...
Winchester, David E; Burkart, Thomas A; Choi, Calvin Y; McKillop, Matthew S; Beyth, Rebecca J; Dahm, Phillipp
2016-06-01
Training in quality improvement (QI) is a pillar of the next accreditation system of the Accreditation Committee on Graduate Medical Education and a growing expectation of physicians for maintenance of certification. Despite this, many postgraduate medical trainees are not receiving training in QI methods. We created the Fellows Applied Quality Training (FAQT) curriculum for cardiology fellows using both didactic and applied components with the goal of increasing confidence to participate in future QI projects. Fellows completed didactic training from the Institute for Healthcare Improvement's Open School and then designed and completed a project to improve quality of care or patient safety. Self-assessments were completed by the fellows before, during, and after the first year of the curriculum. The primary outcome for our curriculum was the median score reported by the fellows regarding their self-confidence to complete QI activities. Self-assessments were completed by 23 fellows. The majority of fellows (15 of 23, 65.2%) reported no prior formal QI training. Median score on baseline self-assessment was 3.0 (range, 1.85-4), which was significantly increased to 3.27 (range, 2.23-4; P = 0.004) on the final assessment. The distribution of scores reported by the fellows indicates that 30% were slightly confident at conducting QI activities on their own, which was reduced to 5% after completing the FAQT curriculum. An interim assessment was conducted after the fellows completed didactic training only; median scores were not different from the baseline (mean, 3.0; P = 0.51). After completion of the FAQT, cardiology fellows reported higher self-confidence to complete QI activities. The increase in self-confidence seemed to be limited to the applied component of the curriculum, with no significant change after the didactic component.
Hao, Zhi-hong; Yao, Jian-zhen; Tang, Rui-ling; Zhang, Xue-mei; Li, Wen-ge; Zhang, Qin
2015-02-01
The method for the determmation of trace boron, molybdenum, silver, tin and lead in geochemical samples by direct current are full spectrum direct reading atomic emission spectroscopy (DC-Arc-AES) was established. Direct current are full spectrum direct reading atomic emission spectrometer with a large area of solid-state detectors has functions of full spectrum direct reading and real-time background correction. The new electrodes and new buffer recipe were proposed in this paper, and have applied for national patent. Suitable analytical line pairs, back ground correcting points of elements and the internal standard method were selected, and Ge was used as internal standard. Multistage currents were selected in the research on current program, and each current set different holding time to ensure that each element has a good signal to noise ratio. Continuous rising current mode selected can effectively eliminate the splash of the sample. Argon as shielding gas can eliminate CN band generating and reduce spectral background, also plays a role in stabilizing the are, and argon flow 3.5 L x min(-1) was selected. Evaporation curve of each element was made, and it was concluded that the evaporation behavior of each element is consistent, and combined with the effects of different spectrographic times on the intensity and background, the spectrographic time of 35s was selected. In this paper, national standards substances were selected as a standard series, and the standard series includes different nature and different content of standard substances which meet the determination of trace boron, molybdenum, silver, tin and lead in geochemical samples. In the optimum experimental conditions, the detection limits for B, Mo, Ag, Sn and Pb are 1.1, 0.09, 0.01, 0.41, and 0.56 microg x g(-1) respectively, and the precisions (RSD, n=12) for B, Mo, Ag, Sn and Pb are 4.57%-7.63%, 5.14%-7.75%, 5.48%-12.30%, 3.97%-10.46%, and 4.26%-9.21% respectively. The analytical accuracy was
High-Resolution Seismics Methods Applied to Till Covered Hard Rock Environments
International Nuclear Information System (INIS)
Bergman, Bjoern
2005-01-01
Reflection seismic and seismic tomography methods can be used to image the upper kilometer of hard bedrock and the loose unconsolidated sediments covering it. Developments of these two methods and their application, as well as identifying issues concerning their usage, are the main focus of the thesis. Data used for this development were acquired at three different sites in Sweden, in Forsmark 140 km north of Stockholm, in the Oskarshamn area in southern Sweden, and in the northern part of the Siljan Ring impact crater area. The reflection seismic data were acquired with long source-receiver offsets relative to some of the targeted depths to be imaged. In the initial processing standard steps were applied, but the uppermost part of the sections were not always clear. The longer offsets imply that pre-stack migration is necessary in order to image the uppermost bedrock as clearly as possible. Careful choice of filters and velocity functions improve the pre-stack migrated image, allowing better correlation with near-surface geological information. The seismic tomography method has been enhanced to calculate, simultaneously with the velocity inversion, optimal corrections to the picked first break travel times in order to compensate for the delays due to the seismic waves passing through the loose sediments covering the bedrock. The reflection seismic processing used in this thesis has produced high-quality images of the upper kilometers, and in one example from the Forsmark site, the image of the uppermost 250 meters of the bedrock has been improved. The three-dimensional orientation of reflections has been determined at the Oskarshamn site. Correlation with borehole data shows that many of these reflections originate from fracture zones. The developed seismic tomography method produces high-detail velocity models for the site in the Siljan impact area and for the Forsmark site. In Forsmark, detailed estimates of the bedrock topography were calculated with the use of
Applying system engineering methods to site characterization research for nuclear waste repositories
International Nuclear Information System (INIS)
Woods, T.W.
1985-01-01
Nuclear research and engineering projects can benefit from the use of system engineering methods. This paper is brief overview illustrating how system engineering methods could be applied in structuring a site characterization effort for a candidate nuclear waste repository. System engineering is simply an orderly process that has been widely used to transform a recognized need into a fully defined system. Such a system may be physical or abstract, natural or man-made, hardware or procedural, as is appropriate to the system's need or objective. It is a way of mentally visualizing all the constituent elements and their relationships necessary to fulfill a need, and doing so compliant with all constraining requirements attendant to that need. Such a system approach provides completeness, order, clarity, and direction. Admittedly, system engineering can be burdensome and inappropriate for those project objectives having simple and familiar solutions that are easily held and controlled mentally. However, some type of documented and structured approach is needed for those objectives that dictate extensive, unique, or complex programs, and/or creation of state-of-the-art machines and facilities. System engineering methods have been used extensively and successfully in these cases. The scientific methods has served well in ordering countless technical undertakings that address a specific question. Similarly, conventional construction and engineering job methods will continue to be quite adequate to organize routine building projects. Nuclear waste repository site characterization projects involve multiple complex research questions and regulatory requirements that interface with each other and with advanced engineering and subsurface construction techniques. There is little doubt that system engineering is an appropriate orchestrating process to structure such diverse elements into a cohesive, well defied project
Resampling method for applying density-dependent habitat selection theory to wildlife surveys.
Tardy, Olivia; Massé, Ariane; Pelletier, Fanie; Fortin, Daniel
2015-01-01
Isodar theory can be used to evaluate fitness consequences of density-dependent habitat selection by animals. A typical habitat isodar is a regression curve plotting competitor densities in two adjacent habitats when individual fitness is equal. Despite the increasing use of habitat isodars, their application remains largely limited to areas composed of pairs of adjacent habitats that are defined a priori. We developed a resampling method that uses data from wildlife surveys to build isodars in heterogeneous landscapes without having to predefine habitat types. The method consists in randomly placing blocks over the survey area and dividing those blocks in two adjacent sub-blocks of the same size. Animal abundance is then estimated within the two sub-blocks. This process is done 100 times. Different functional forms of isodars can be investigated by relating animal abundance and differences in habitat features between sub-blocks. We applied this method to abundance data of raccoons and striped skunks, two of the main hosts of rabies virus in North America. Habitat selection by raccoons and striped skunks depended on both conspecific abundance and the difference in landscape composition and structure between sub-blocks. When conspecific abundance was low, raccoons and striped skunks favored areas with relatively high proportions of forests and anthropogenic features, respectively. Under high conspecific abundance, however, both species preferred areas with rather large corn-forest edge densities and corn field proportions. Based on random sampling techniques, we provide a robust method that is applicable to a broad range of species, including medium- to large-sized mammals with high mobility. The method is sufficiently flexible to incorporate multiple environmental covariates that can reflect key requirements of the focal species. We thus illustrate how isodar theory can be used with wildlife surveys to assess density-dependent habitat selection over large
Photonic simulation method applied to the study of structural color in Myxomycetes.
Dolinko, Andrés; Skigin, Diana; Inchaussandague, Marina; Carmaran, Cecilia
2012-07-02
We present a novel simulation method to investigate the multicolored effect of the Diachea leucopoda (Physarales order, Myxomycetes class), which is a microorganism that has a characteristic pointillistic iridescent appearance. It was shown that this appearance is of structural origin, and is produced within the peridium -protective layer that encloses the mass of spores-, which is basically a corrugated sheet of a transparent material. The main characteristics of the observed color were explained in terms of interference effects using a simple model of homogeneous planar slab. In this paper we apply a novel simulation method to investigate the electromagnetic response of such structure in more detail, i.e., taking into account the inhomogeneities of the biological material within the peridium and its curvature. We show that both features, which could not be considered within the simplified model, affect the observed color. The proposed method is of great potential for the study of biological structures, which present a high degree of complexity in the geometrical shapes as well as in the materials involved.
Berthels, Nele; Matthijs, Gert; Van Overwalle, Geertrui
2011-11-01
Recent reports in Europe and the United States raise concern about the potential negative impact of gene patents on the freedom to operate of diagnosticians and on the access of patients to genetic diagnostic services. Patents, historically seen as legal instruments to trigger innovation, could cause undesired side effects in the public health domain. Clear empirical evidence on the alleged hindering effect of gene patents is still scarce. We therefore developed a patent categorization method to determine which gene patents could indeed be problematic. The method is applied to patents relevant for genetic testing of spinocerebellar ataxia (SCA). The SCA test is probably the most widely used DNA test in (adult) neurology, as well as one of the most challenging due to the heterogeneity of the disease. Typically tested as a gene panel covering the five common SCA subtypes, we show that the patenting of SCA genes and testing methods and the associated licensing conditions could have far-reaching consequences on legitimate access to this gene panel. Moreover, with genetic testing being increasingly standardized, simply ignoring patents is unlikely to hold out indefinitely. This paper aims to differentiate among so-called 'gene patents' by lifting out the truly problematic ones. In doing so, awareness is raised among all stakeholders in the genetic diagnostics field who are not necessarily familiar with the ins and outs of patenting and licensing.
IAEA-ASSET's root cause analysis method applied to sodium leakage incident at Monju
International Nuclear Information System (INIS)
Watanabe, Norio; Hirano, Masashi
1997-08-01
The present study applied the ASSET (Analysis and Screening of Safety Events Team) methodology (This method identifies occurrences such as component failures and operator errors, identifies their respective direct/root causes and determines corrective actions.) to the analysis of the sodium leakage incident at Monju, based on the published reports by mainly the Science and Technology Agency, aiming at systematic identification of direct/root causes and corrective actions, and discussed the effectiveness and problems of the ASSET methodology. The results revealed the following seven occurrences and showed the direct/root causes and contributing factors for the individual occurrences: failure of thermometer well tube, delayed reactor manual trip, inadequate continuous monitoring of leakage, misjudgment of leak rate, non-required operator action (turbine trip), retarded emergency sodium drainage, and retarded securing of ventilation system. Most of the occurrences stemmed from deficiencies in emergency operating procedures (EOPs), which were mainly caused by defects in the EOP preparation process and operator training programs. The corrective actions already proposed in the published reports were reviewed, identifying issues to be further studied. Possible corrective actions were discussed for these issues. The present study also demonstrated the effectiveness of the ASSET methodology and pointed out some problems, for example, in delineating causal relations among occurrences, for applying it to the detail and systematic analysis of event direct/root causes and determination of concrete measures. (J.P.N.)
Bamberger, Katharine T
2016-03-01
The use of intensive longitudinal methods (ILM)-rapid in situ assessment at micro timescales-can be overlaid on RCTs and other study designs in applied family research. Particularly, when done as part of a multiple timescale design-in bursts over macro timescales-ILM can advance the study of the mechanisms and effects of family interventions and processes of family change. ILM confers measurement benefits in accurately assessing momentary and variable experiences and captures fine-grained dynamic pictures of time-ordered processes. Thus, ILM allows opportunities to investigate new research questions about intervention effects on within-subject (i.e., within-person, within-family) variability (i.e., dynamic constructs) and about the time-ordered change process that interventions induce in families and family members beginning with the first intervention session. This paper discusses the need and rationale for applying ILM to family intervention evaluation, new research questions that can be addressed with ILM, example research using ILM in the related fields of basic family research and the evaluation of individual-based interventions. Finally, the paper touches on practical challenges and considerations associated with ILM and points readers to resources for the application of ILM.
A method of applying two-pump system in automatic transmissions for energy conservation
Directory of Open Access Journals (Sweden)
Peng Dong
2015-06-01
Full Text Available In order to improve the hydraulic efficiency, modern automatic transmissions tend to apply electric oil pump in their hydraulic system. The electric oil pump can support the mechanical oil pump for cooling, lubrication, and maintaining the line pressure at low engine speeds. In addition, the start–stop function can be realized by means of the electric oil pump; thus, the fuel consumption can be further reduced. This article proposes a method of applying two-pump system (one electric oil pump and one mechanical oil pump in automatic transmissions based on the forward driving simulation. A mathematical model for calculating the transmission power loss is developed. The power loss transfers to heat which requires oil flow for cooling and lubrication. A leakage model is developed to calculate the leakage of the hydraulic system. In order to satisfy the flow requirement, a flow-based control strategy for the electric oil pump is developed. Simulation results of different driving cycles show that there is a best combination of the size of electric oil pump and the size of mechanical oil pump with respect to the optimal energy conservation. Besides, the two-pump system can also satisfy the requirement of the start–stop function. This research is extremely valuable for the forward design of a two-pump system in automatic transmissions with respect to energy conservation and start–stop function.
DEFF Research Database (Denmark)
Gohil, Ghanshyamsinh Vijaysinh; Wang, Huai; Liserre, Marco
2014-01-01
A method to selectively control the amount of dc link voltage ripple by processing desired reactive power by a DC/DC converter in isolated AC/DC or AC/DC/AC system is proposed. The concept can reduce the dc link capacitors used for balancing the input and output power and thereby limiting...... the voltage ripple. It allows the use of smaller dc link capacitor and hence a longer lifetime and at the same time high power density and low cost can be achieved. The isolated DC/DC converter is controlled to process the desired reactive power in addition to the active power. The control system to achieve...
Improvement in the DTVG detection method as applied to cast austeno-ferritic steels
International Nuclear Information System (INIS)
Francois, D.
1996-05-01
Initially, the so-called DTVG method was developed to improve detection and (lengthwise) dimensioning of cracks in austenitic steel assembly welds. The results obtained during the study and the structural similarity between austenitic and austeno-ferritic steels led us to carry out research into adapting the method on a sample the material of which is representative of the cast steels used in PWR primary circuit bends. The method was first adapted for use on thick-wall cast austeno-ferritic steel structures and was validated for zero ultrasonic beam incidence and for a flat sample with machine-finished reflectors. A second study was carried out notably to allow for non-zero ultrasonic beam incidence and to look at the method's validity when applied to a non-flat geometry. There were three principal goals to the research; adapting the process to take into account the special case of oblique ultrasonic beam incidence (B image handling), examining the effect of non-flat geometry on the detection method, and evaluating the performance of the method on actual defects (shrinkage cavities). We began by focusing on solving the problem of oblique incidence. Having decided on automatic refracted angle determination, the problem could only be solves by locking the algorithm on a representative image of the suspect material comprising an indicator. We then used a simple geometric model to quantify the deformation of the indicators on a B-scan image due to a non-flat translator/part interface. Finally, tests were carried out on measurements acquired from flat samples containing artificial and real defects so that the overall performance of the method after development could be assessed. This work has allowed the DTVG detection method to be adapted for use with B-scan images acquired with a non-zero ultrasonic beam incidence angle. Moreover, we have been able to show that for similar geometries to those of the cast bends and for deep defects the deformation of the indicators due
Applying RP-FDM Technology to Produce Prototype Castings Using the Investment Casting Method
Directory of Open Access Journals (Sweden)
M. Macků
2012-09-01
Full Text Available The research focused on the production of prototype castings, which is mapped out starting from the drawing documentation up to theproduction of the casting itself. The FDM method was applied for the production of the 3D pattern. Its main objective was to find out whatdimensional changes happened during individual production stages, starting from the 3D pattern printing through a silicon mouldproduction, wax patterns casting, making shells, melting out wax from shells and drying, up to the production of the final casting itself.Five measurements of determined dimensions were made during the production, which were processed and evaluated mathematically.A determination of shrinkage and a proposal of measures to maintain the dimensional stability of the final casting so as to meetrequirements specified by a customer were the results.
Comparison of gradient methods for gain tuning of a PD controller applied on a quadrotor system
Kim, Jinho; Wilkerson, Stephen A.; Gadsden, S. Andrew
2016-05-01
Many mechanical and electrical systems have utilized the proportional-integral-derivative (PID) control strategy. The concept of PID control is a classical approach but it is easy to implement and yields a very good tracking performance. Unmanned aerial vehicles (UAVs) are currently experiencing a significant growth in popularity. Due to the advantages of PID controllers, UAVs are implementing PID controllers for improved stability and performance. An important consideration for the system is the selection of PID gain values in order to achieve a safe flight and successful mission. There are a number of different algorithms that can be used for real-time tuning of gains. This paper presents two algorithms for gain tuning, and are based on the method of steepest descent and Newton's minimization of an objective function. This paper compares the results of applying these two gain tuning algorithms in conjunction with a PD controller on a quadrotor system.
Study of different ultrasonic focusing methods applied to non destructive testing
International Nuclear Information System (INIS)
El Amrani, M.
1995-01-01
The work presented in this thesis concerns the study of different ultrasonic focusing techniques applied to Nondestructive Testing (mechanical focusing and electronic focusing) and compares their capabilities. We have developed a model to predict the ultrasonic field radiated into a solid by water-coupled transducers. The model is based upon the Rayleigh integral formulation, modified to take account the refraction at the liquid-solid interface. The model has been validated by numerous experiments in various configurations. Running this model and the associated software, we have developed new methods to optimize focused transducers and studied the characteristics of the beam generated by transducers using various focusing techniques. (author). 120 refs., 95 figs., 4 appends
Adding randomness controlling parameters in GRASP method applied in school timetabling problem
Directory of Open Access Journals (Sweden)
Renato Santos Pereira
2017-09-01
Full Text Available This paper studies the influence of randomness controlling parameters (RCP in first stage GRASP method applied in graph coloring problem, specifically school timetabling problems in a public high school. The algorithm (with the inclusion of RCP was based on critical variables identified through focus groups, whose weights can be adjusted by the user in order to meet the institutional needs. The results of the computational experiment, with 11-year-old data (66 observations processed at the same high school show that the inclusion of RCP leads to significantly lowering the distance between initial solutions and local minima. The acceptance and the use of the solutions found allow us to conclude that the modified GRASP, as has been constructed, can make a positive contribution to this timetabling problem of the school in question.
Applying RP-FDM Technology to Produce Prototype Castings Using the Investment Casting Method
Directory of Open Access Journals (Sweden)
Macků M.
2012-09-01
Full Text Available The research focused on the production of prototype castings, which is mapped out starting from the drawing documentation up to the production of the casting itself. The FDM method was applied for the production of the 3D pattern. Its main objective was to find out what dimensional changes happened during individual production stages, starting from the 3D pattern printing through a silicon mould production, wax patterns casting, making shells, melting out wax from shells and drying, up to the production of the final casting itself. Five measurements of determined dimensions were made during the production, which were processed and evaluated mathematically. A determination of shrinkage and a proposal of measures to maintain the dimensional stability of the final casting so as to meet requirements specified by a customer were the results.
Applied methods for mitigation of damage by stress corrosion in BWR type reactors
International Nuclear Information System (INIS)
Hernandez C, R.; Diaz S, A.; Gachuz M, M.; Arganis J, C.
1998-01-01
The Boiling Water nuclear Reactors (BWR) have presented stress corrosion problems, mainly in components and pipes of the primary system, provoking negative impacts in the performance of energy generator plants, as well as the increasing in the radiation exposure to personnel involucred. This problem has caused development of research programs, which are guided to find solution alternatives for the phenomena control. Among results of greater relevance the control for the reactor water chemistry stands out particularly in the impurities concentration and oxidation of radiolysis products; as well as the supervision in the materials selection and the stresses levels reduction. The present work presents the methods which can be applied to diminish the problems of stress corrosion in BWR reactors. (Author)
Applied methods and techniques for mechatronic systems modelling, identification and control
Zhu, Quanmin; Cheng, Lei; Wang, Yongji; Zhao, Dongya
2014-01-01
Applied Methods and Techniques for Mechatronic Systems brings together the relevant studies in mechatronic systems with the latest research from interdisciplinary theoretical studies, computational algorithm development and exemplary applications. Readers can easily tailor the techniques in this book to accommodate their ad hoc applications. The clear structure of each paper, background - motivation - quantitative development (equations) - case studies/illustration/tutorial (curve, table, etc.) is also helpful. It is mainly aimed at graduate students, professors and academic researchers in related fields, but it will also be helpful to engineers and scientists from industry. Lei Liu is a lecturer at Huazhong University of Science and Technology (HUST), China; Quanmin Zhu is a professor at University of the West of England, UK; Lei Cheng is an associate professor at Wuhan University of Science and Technology, China; Yongji Wang is a professor at HUST; Dongya Zhao is an associate professor at China University o...
International Nuclear Information System (INIS)
Ramirez, A.L.
1983-01-01
This discussion focuses on the use of borehole to borehole geophysical measurements to detect geological discontinuities in High Level Waste (HLW) repository sites. The need for these techniques arises from: (a) the requirement that a HLW repository's characteristics and projected performance be known with a high degree of confidence; and (b) the inadequacy of other geophysical methods in mapping fractures. Probing configurations which can be used to characterize HLW sites are described. Results from experiments in which these techniques were applied to problems similar to those expected at repository sites are briefly discussed. The use of a procedure designed to reduce uncertainty associated with all geophysical exploration techniques is proposed; key components of the procedure are defined
Overview of Multi-DC-Bus Solutions for DC Microgrids
DEFF Research Database (Denmark)
Ricchiuto, D.; Mastromauro, R.A.; Liserre, Marco
2013-01-01
DC Microgrids have recently received a lot of attention in the last years due to high penetration of renewable energy sources as well as distributed energy storage systems. In the future DC microgrids could be preferable respect to AC microgrids in terms of redundancy since multi-DC-Bus solutions...... could provide a continuative power supply to the loads. An overview of Multi-DC-Bus solutions is presented in this paper. The performances are compared on the basis of possible DC microgrid configurations, redundancy, different DC voltage levels....
Directory of Open Access Journals (Sweden)
de Paris Marcel
2007-11-01
Full Text Available Abstract Background Surgical orthopedic treatment of the mandible depends on the development of techniques resulting in adequate healing processes. In a new technical and conceptual alternative recently introduced by Puricelli, osteotomy is performed in a more distal region, next to the mental foramen. The method results in an increased area of bone contact, resulting in larger sliding rates among bone segments. This work aimed to investigate the mechanical stability of the Puricelli osteotomy design. Methods Laboratory tests complied with an Applied Mechanics protocol, in which results from the Control group (without osteotomy were compared with those from Test I (Obwegeser-Dal Pont osteotomy and Test II (Puricelli osteotomy groups. Mandible edentulous prototypes were scanned using computerized tomography, and digitalized images were used to build voxel-based finite element models. A new code was developed for solving the voxel-based finite elements equations, using a reconditioned conjugate gradients iterative solver. The Magnitude of Displacement and von Mises equivalent stress fields were compared among the three groups. Results In Test Group I, maximum stress was seen in the region of the rigid internal fixation plate, with value greater than those of Test II and Control groups. In Test Group II, maximum stress was in the same region as in Control group, but was lower. The results of this comparative study using the Finite Element Analysis suggest that Puricelli osteotomy presents better mechanical stability than the original Obwegeser-Dal Pont technique. The increased area of the proximal segment and consequent decrease of the size of lever arm applied to the mandible in the modified technique yielded lower stress values, and consequently greater stability of the bone segments. Conclusion This work showed that Puricelli osteotomy of the mandible results in greater mechanical stability when compared to the original technique introduced by
Infrared thermography inspection methods applied to the target elements of W7-X Divertor
International Nuclear Information System (INIS)
Missirlian, M.; Durocher, A.; Schlosser, J.; Farjon, J.-L.; Vignal, N.; Traxler, H.; Schedler, B.; Boscary, J.
2006-01-01
As heat exhaust capability and lifetime of plasma-facing component (PFC) during in-situ operation are linked to the manufacturing quality, a set of non-destructive testing must be operated during R-and-D and manufacturing phases. Within this framework, advanced non-destructive examination (NDE) methods are one of the key issues to achieve a high level of quality and reliability of joining techniques in the production of high heat flux components but also to develop and built successfully PFCs for a next generation of fusion devices. In this frame, two NDE infrared thermographic approaches, which have been recently applied to the qualification of CFC target elements of the W7-X divertor during the first series production will be discussed in this paper. The first one, developed by CEA (SATIR facility) and used with successfully to the control of the mass-produced actively cooled PFCs on Tore Supra, is based on the transient thermography where the testing protocol consists in inducing a thermal transient within the heat sink structure by an alternative hot/cold water flow. The second one, recently developed by PLANSEE (ARGUS facility), is based on the pulsed thermography where the component is heated externally by a single powerful flash of light. Results obtained on qualification experiences performed during the first series production of W7-X divertor components representing about thirty mock-ups with artificial and manufacturing defects, demonstrated the capabilities of these two methods and raised the efficiency of inspection to a level which is appropriate for industrial application. This comparative study, associated to a cross-checking analysis between the high heat flux performance tests and these inspection methods by infrared thermography, showed a good reproducibility and allowed to set a detectable limit specific at each method. Finally, the detectability of relevant defects showed excellent coincidence with thermal images obtained from high heat flux
Emery, B. M.; Washburn, L.; Mezic, I.; Loire, S.; Arbabi, H.; Ohlmann, C.; Harlan, J.
2016-02-01
We apply several analysis methods to HF radar ocean surface current maps to investigate improvements in trajectory modeling. Results from a Lagrangian Stochastic Model (LSM) are compared with methods based on dynamical systems theory: hypergraphs and Koopman mode analysis. The LSM produces trajectories by integrating Eulerian fields from the HF radar, and accounts for sub-grid scale velocity variability by including a random component based on the Lagrangian decorrelation time. Hypergraphs also integrate the HF radar maps in time, showing areas of strain, strain-rotation, and mixing, by plotting the relative strengths of the eigenvalues of the gradient of the time-averaged Lagrangian velocity. Koopman mode analysis decomposes the velocity field into modes of variability, similarly to EOF or a Fourier analysis, though each Koopman mode varies in time with a distinct frequency. Each method simulates oil drift from a the oil spill of May, 2015 that occurred within the coverage area of the HF radars, in the Santa Barbara Channel near Refugio Beach, CA. Preliminary results indicate some skill in determining the transport of oil when compare to publicly available observations of oil in the Santa Barbara Channel. These simulations have not shown a connection between the Refugio spill site and oil observations in the Santa Monica Bay, near Los Angeles CA, though accumulation zones shown by the hypergraphs correlate in time and space with these observations. Improvements in the HF radar coverage and accuracy were observed during the spill by the deployment of an additional HF radar site near Gaviota, CA. Presently we are collecting observations of oil on beaches and in the ocean, determining the role of winds in the oil movement, and refining the methods. Some HF radar data is being post-processed to incorporate recent antenna calibrations for sites in Santa Monica Bay. We will evaluate effects of the newly processed data on analysis results.
Balancing a U-Shaped Assembly Line by Applying Nested Partitions Method
Energy Technology Data Exchange (ETDEWEB)
Bhagwat, Nikhil V. [Iowa State Univ., Ames, IA (United States)
2005-01-01
In this study, we applied the Nested Partitions method to a U-line balancing problem and conducted experiments to evaluate the application. From the results, it is quite evident that the Nested Partitions method provided near optimal solutions (optimal in some cases). Besides, the execution time is quite short as compared to the Branch and Bound algorithm. However, for larger data sets, the algorithm took significantly longer times for execution. One of the reasons could be the way in which the random samples are generated. In the present study, a random sample is a solution in itself which requires assignment of tasks to various stations. The time taken to assign tasks to stations is directly proportional to the number of tasks. Thus, if the number of tasks increases, the time taken to generate random samples for the different regions also increases. The performance index for the Nested Partitions method in the present study was the number of stations in the random solutions (samples) generated. The total idle time for the samples can be used as another performance index. ULINO method is known to have used a combination of bounds to come up with good solutions. This approach of combining different performance indices can be used to evaluate the random samples and obtain even better solutions. Here, we used deterministic time values for the tasks. In industries where majority of tasks are performed manually, the stochastic version of the problem could be of vital importance. Experimenting with different objective functions (No. of stations was used in this study) could be of some significance to some industries where in the cost associated with creation of a new station is not the same. For such industries, the results obtained by using the present approach will not be of much value. Labor costs, task incompletion costs or a combination of those can be effectively used as alternate objective functions.
Autonomous Control Strategy of DC Microgrid for Islanding Mode Using Power Line Communication
Directory of Open Access Journals (Sweden)
Dong-Keun Jeong
2018-04-01
Full Text Available This paper proposes a DC-bus signaling (DBS method for autonomous power management in a DC microgrid, used to improve its reliability. Centralized power management systems require communication between the power sources and loads. However, the DBS method operates based on the common DC-bus voltage and does not require communication. Based on the DC-bus voltage band, the DC-bus voltage can be used to inform the status of the DC-bus in various scenarios. The DC microgrid operates independently to maintain the system stably in the DC-bus voltage band. The DC microgrid can be divided into a grid-connected mode and an islanding mode. This paper proposes a control strategy based on power management of various independent components in islanding mode. In addition, the autonomous control method for switching the converter’s operation between grid-connected mode and islanding mode is proposed. A DC microgrid test bed consisting of a grid-connected AC/DC converter, a bidirectional DC/DC converter, a renewable energy simulator, DC home appliances and a DC-bus protector is used to test the proposed control strategy. The proposed autonomous control strategy is experimentally verified using the DC microgrid test bed.
Din, Tengku Noor Daimah Tengku; Jamayet, Nafij; Rajion, Zainul Ahmad; Luddin, Norhayati; Abdullah, Johari Yap; Abdullah, Abdul Manaf; Yahya, Suzana
2016-12-01
Facial defects are either congenital or caused by trauma or cancer where most of them affect the person appearance. The emotional pressure and low self-esteem are problems commonly related to patient with facial defect. To overcome this problem, silicone prosthesis was designed to cover the defect part. This study describes the techniques in designing and fabrication for facial prosthesis applying computer aided method and manufacturing (CADCAM). The steps of fabricating the facial prosthesis were based on a patient case. The patient was diagnosed for Gorlin Gotz syndrome and came to Hospital Universiti Sains Malaysia (HUSM) for prosthesis. The 3D image of the patient was reconstructed from CT data using MIMICS software. Based on the 3D image, the intercanthal and zygomatic measurements of the patient were compared with available data in the database to find the suitable nose shape. The normal nose shape for the patient was retrieved from the nasal digital library. Mirror imaging technique was used to mirror the facial part. The final design of facial prosthesis including eye, nose and cheek was superimposed to see the result virtually. After the final design was confirmed, the mould design was created. The mould of nasal prosthesis was printed using Objet 3D printer. Silicone casting was done using the 3D print mould. The final prosthesis produced from the computer aided method was acceptable to be used for facial rehabilitation to provide better quality of life.
Goal oriented soil mapping: applying modern methods supported by local knowledge: A review
Pereira, Paulo; Brevik, Eric; Oliva, Marc; Estebaranz, Ferran; Depellegrin, Daniel; Novara, Agata; Cerda, Artemi; Menshov, Oleksandr
2017-04-01
In the recent years the amount of soil data available increased importantly. This facilitated the production of better and accurate maps, important for sustainable land management (Pereira et al., 2017). Despite these advances, the human knowledge is extremely important to understand the natural characteristics of the landscape. The knowledge accumulated and transmitted generation after generation is priceless, and should be considered as a valuable data source for soil mapping and modelling. The local knowledge and wisdom can complement the new advances in soil analysis. In addition, farmers are the most interested in the participation and incorporation of their knowledge in the models, since they are the end-users of the study that soil scientists produce. Integration of local community's vision and understanding about nature is assumed to be an important step to the implementation of decision maker's policies. Despite this, many challenges appear regarding the integration of local and scientific knowledge, since in some cases there is no spatial correlation between folk and scientific classifications, which may be attributed to the different cultural variables that influence local soil classification. The objective of this work is to review how modern soil methods incorporated local knowledge in their models. References Pereira, P., Brevik, E., Oliva, M., Estebaranz, F., Depellegrin, D., Novara, A., Cerda, A., Menshov, O. (2017) Goal Oriented soil mapping: applying modern methods supported by local knowledge. In: Pereira, P., Brevik, E., Munoz-Rojas, M., Miller, B. (Eds.) Soil mapping and process modelling for sustainable land use management (Elsevier Publishing House) ISBN: 9780128052006
[An experimental assessment of methods for applying intestinal sutures in intestinal obstruction].
Akhmadudinov, M G
1992-04-01
The results of various methods used in applying intestinal sutures in obturation were studied. Three series of experiments were conducted on 30 dogs--resection of the intestine after obstruction with the formation of anastomoses by means of double-row suture (Albert--Shmiden--Lambert) in the first series (10 dogs), by a single-row suture after V. M. Mateshchuk [correction of Mateshuku] in the second series, and bu a single-row stretching suture suggested by the author in the third series. The postoperative complications and the parameters of physical airtightness of the intestinal anastomosis were studied in dynamics in the experimental animals. The results of the study: incompetence of the anastomosis sutures in the first series 6, in the second 4, and in the third series one. Adhesions occurred in all animals of the first and second series and in 2 of the third series. Six dogs of the first series died, 4 of the second, and one of the third. Study of the dynamics of the results showed a direct connection of the complications with the parameters of the physical airtightness of the anastomosis, and the last-named with the method of the intestinal suture. Relatively better results were noted in formation of the anastomosis by means of our suggested stretshing continuous suture passed through the serous, muscular, and submucous coats of the intestine.
Bublievskii, A. F.; Galinovskii, A. A.; Gorbunov, A. V.; Zhdanok, S. A.; Koval', V. A.; Sharakhovskii, L. I.; Dolgolenko, G. V.; Skomorokhov, D. S.
2006-07-01
Comparative results of investigating the parameters of plasmas generated by atmospheric-pressure electric-arc plasmatrons of two types operating in the regime of simultaneous partial oxidation of hydrocarbons and their pyrolysis, have been given. It has been established by spectral and thermophysical measurements that the component composition of the plasma and its thermal characteristics at exit from a d.c. plasmatron significantly differ from the parameters of a plasmatron of the second type — an a.c. plasmatron with rail-shaped electrodes of the gliding-arc type. The temperature nonequilibrium and the presence of the carbon dimers C2 in the plasma (in the absence of the monomer C) generated by the rail-shaped-electrode plasmatron point to the fact that realization of the synthesis of fullerene-containing particles and, probably, particles containing nanotubes is, in principle, possible in reactors based on it, just as in more energy-intensive reactors with low-voltage d.c. arc plasmatrons.
Campiotti, Richard H.; Hopwood, James E.
1990-01-01
A system for starting an arc for welding uses three DC power supplies, a high voltage supply for initiating the arc, an intermediate voltage supply for sustaining the arc, and a low voltage welding supply directly connected across the gap after the high voltage supply is disconnected.
International Nuclear Information System (INIS)
Zhang Huiqun
2009-01-01
By using a new coupled Riccati equations, a direct algebraic method, which was applied to obtain exact travelling wave solutions of some complex nonlinear equations, is improved. And the exact travelling wave solutions of the complex KdV equation, Boussinesq equation and Klein-Gordon equation are investigated using the improved method. The method presented in this paper can also be applied to construct exact travelling wave solutions for other nonlinear complex equations.
Comparison of virological methods applied on african swine fever diagnosis in Brazil, 1978
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Tânia Rosária Pereira Freitas
2015-10-01
Full Text Available ABSTRACT. Freitas T.R.P., Souza A.C., Esteves E.G. & Lyra T.M.P. [Comparison of virological methods applied on african swine fever diagnosis in Brazil, 1978.] Comparação dos métodos virológicos aplicados no diagnóstico da peste suína africana no Brasil, 1978. Revista Brasileira de Medicina Veterinária, 37(3:255-263, 2015. Laboratório Nacional Agropecuário, Ministério da Agricultura, Pecuária e Abastecimento, Avenida Rômulo Joviano, s/n, Caixa postal 35/50, Pedro Leopoldo, MG 33600-000, Brasil. taniafrei@hotmail.com The techniques of leucocytes haemadsorption (HAD for the African Swine Fever (ASF virus isolation and the fluorescent antigens tissue samples (FATS for virus antigens detection were implanted in the ASF eradication campaign in the country. The complementary of techniques was studied considering the results obtained when the HAD and FATS were concomitantly applied on the same pig tissue samples. The results of 22, 56 and 30 pigs samples from of the States of Rio de Janeiro (RJ, São Paulo (SP and Paraná (PR, respectively, showed that in RJ 11 (50%; in SP, 28 (50% and in PR, 15 (50% samples were positive in the HAD, while, RJ, 18 (82%; SP, 33 (58% and PR, 17 (57% were positive in the FATS. In the universe of 108 samples submitted to both the tests, 83 (76.85% were positive in at least one of the tests, which characterized ASF positivity. Among the positive samples, 28 (34% have presented HAD negative results and 15 (18% have presented FATS negative results. The achievement of applying simultaneously the both tests was the reduction of false- negative results, conferring more ASF accurate laboratorial diagnosis, besides to show the tests complementary. This aspect is fundamentally importance concern with a disease eradiation program to must avoid false negative results. Evidences of low virulence ASFV strains in Brazilian ASF outbreaks and also the distribution of ASF outbreaks by the mesoregions of each State were discussed
Branney, Jonathan; Priego-Hernández, Jacqueline
2018-02-01
It is important for nurses to have a thorough understanding of the biosciences such as pathophysiology that underpin nursing care. These courses include content that can be difficult to learn. Team-based learning is emerging as a strategy for enhancing learning in nurse education due to the promotion of individual learning as well as learning in teams. In this study we sought to evaluate the use of team-based learning in the teaching of applied pathophysiology to undergraduate student nurses. A mixed methods observational study. In a year two, undergraduate nursing applied pathophysiology module circulatory shock was taught using Team-based Learning while all remaining topics were taught using traditional lectures. After the Team-based Learning intervention the students were invited to complete the Team-based Learning Student Assessment Instrument, which measures accountability, preference and satisfaction with Team-based Learning. Students were also invited to focus group discussions to gain a more thorough understanding of their experience with Team-based Learning. Exam scores for answers to questions based on Team-based Learning-taught material were compared with those from lecture-taught material. Of the 197 students enrolled on the module, 167 (85% response rate) returned the instrument, the results from which indicated a favourable experience with Team-based Learning. Most students reported higher accountability (93%) and satisfaction (92%) with Team-based Learning. Lectures that promoted active learning were viewed as an important feature of the university experience which may explain the 76% exhibiting a preference for Team-based Learning. Most students wanted to make a meaningful contribution so as not to let down their team and they saw a clear relevance between the Team-based Learning activities and their own experiences of teamwork in clinical practice. Exam scores on the question related to Team-based Learning-taught material were comparable to those
Lesellier, E; Mith, D; Dubrulle, I
2015-12-04
necessary, two-step gradient elution. The developed methods were then applied to real cosmetic samples to assess the method specificity, with regards to matrix interferences, and calibration curves were plotted to evaluate quantification. Besides, depending on the matrix and on the studied compounds, the importance of the detector type, UV or ELSD (evaporative light-scattering detection), and of the particle size of the stationary phase is discussed. Copyright © 2015 Elsevier B.V. All rights reserved.
dc Arc Fault Effect on Hybrid ac/dc Microgrid
Fatima, Zahra
The advent of distributed energy resources (DER) and reliability and stability problems of the conventional grid system has given rise to the wide spread deployment of microgrids. Microgrids provide many advantages by incorporating renewable energy sources and increasing the reliability of the grid by isolating from the main grid in case of an outage. AC microgrids have been installed all over the world, but dc microgrids have been gaining interest due to the advantages they provide over ac microgrids. However the entire power network backbone is still ac and dc microgrids require expensive converters to connect to the ac power network. As a result hybrid ac/dc microgrids are gaining more attention as it combines the advantages of both ac and dc microgrids such as direct integration of ac and dc systems with minimum number of conversions which increases the efficiency by reducing energy losses. Although dc electric systems offer many advantages such as no synchronization and no reactive power, successful implementation of dc systems requires appropriate protection strategies. One unique protection challenge brought by the dc systems is dc arc faults. A dc arc fault is generated when there is a gap in the conductor due to insulation degradation and current is used to bridge the gap, resulting in an arc with very high temperature. Such a fault if it goes undetected and is not extinguished can cause damage to the entire system and cause fires. The purpose of the research is to study the effect of the dc arc fault at different locations in the hybrid ac/dc microgrid and provide insight on the reliability of the grid components when it is impacted by arc faults at various locations in the grid. The impact of dc arc fault at different locations on the performance of the PV array, wind generation, and constant power loads (CPL) interfaced with dc/dc converters is studied. MATLAB/Simulink is used to model the hybrid ac/dc microgrid and arc fault.
Enhancement of Voltage Stability of DC Smart Grid During Islanded Mode by Load Shedding Scheme
Nassor, Thabit Salim; Senjyu, Tomonobu; Yona, Atsushi
2015-10-01
This paper presents the voltage stability of a DC smart grid based on renewable energy resources during grid connected and isolated modes. During the islanded mode the load shedding, based on the state of charge of the battery and distribution line voltage, was proposed for voltage stability and reservation of critical load power. The analyzed power system comprises a wind turbine, a photovoltaic generator, storage battery as controllable load, DC loads, and power converters. A fuzzy logic control strategy was applied for power consumption control of controllable loads and the grid-connected dual active bridge series resonant converters. The proposed DC Smart Grid operation has been verified by simulation using MATLAB® and PLECS® Blockset. The obtained results show the effectiveness of the proposed method.
On the DC loop modes in the MOT solution of the time domain EFIE
Shi, Yifei
2014-07-01
When marching-on-in-time (MOT) method is applied to solve the time domain electric field integral equation (TD-EFIE), DC loop modes are always observed in the solution. In theory these modes should not be observed since they do not satisfy the relaxed initial conditions. Their appearance is attributed to numerical errors. It is shown here that when Rao-Wilton-Glisson basis and Lagrange interpolation functions are used to discretize the TD-EFIE, errors due to this space-time discretization have zero impact on the DC loop modes. Numerical experiments demonstrate that the numerical errors due to approximate solution of the MOT matrix system have more dominant impact on DC loop modes in the MOT solution.
Directory of Open Access Journals (Sweden)
Zheng Wang
2016-01-01
Full Text Available Three-port isolated (TPI bidirectional DC/DC converters have three energy ports and offer advantages of large voltage gain, galvanic isolation ability and high power density. For this reason this kind of converters are suitable to connect different energy sources and loads in electric and hybrid vehicles. The purpose of this paper is to propose chaotic modulation and the related control scheme for TPI bidirectional DC/DC converters, in such a way that the switching harmonic peaks can be suppressed in spectrum and the conducted electromagnetic interference (EMI is reduced. Two chaotic modulation strategies, namely the continuously chaotic modulation and the discretely chaotic modulation are presented. These two chaotic modulation strategies are applied for TPI bidirectional DC/DC converters with shifted-phase angle based control and phase-shifted PWM control. Both simulation and experiments are given to verify the validity of the proposed chaotic modulation-based control schemes.
Research on key technology of planning and design for AC/DC hybrid distribution network
Shen, Yu; Wu, Guilian; Zheng, Huan; Deng, Junpeng; Shi, Pengjia
2018-04-01
With the increasing demand of DC generation and DC load, the development of DC technology, AC and DC distribution network integrating will become an important form of future distribution network. In this paper, the key technology of planning and design for AC/DC hybrid distribution network is proposed, including the selection of AC and DC voltage series, the design of typical grid structure and the comprehensive evaluation method of planning scheme. The research results provide some ideas and directions for the future development of AC/DC hybrid distribution network.
Non-parametric order statistics method applied to uncertainty propagation in fuel rod calculations
International Nuclear Information System (INIS)
Arimescu, V.E.; Heins, L.
2001-01-01
method, which is computationally efficient, is presented for the evaluation of the global statement. It is proved that, r, the expected fraction of fuel rods exceeding a certain limit is equal to the (1-r)-quantile of the overall distribution of all possible values from all fuel rods. In this way, the problem is reduced to that of estimating a certain quantile of the overall distribution, and the same techniques used for a single rod distribution can be applied again. A simplified test case was devised to verify and validate the methodology. The fuel code was replaced by a transfer function dependent on two input parameters. The function was chosen so that analytic results could be obtained for the distribution of the output. This offers a direct validation for the statistical procedure. Also, a sensitivity study has been performed to analyze the effect on the final outcome of the sampling procedure, simple Monte Carlo and Latin Hypercube Sampling. Also, the effect on the accuracy and bias of the statistical results due to the size of the sample was studied and the conclusion was reached that the results of the statistical methodology are typically conservative. In the end, an example of applying these statistical techniques to a PWR reload is presented together with the improvements and new insights the statistical methodology brings to fuel rod design calculations. (author)
2010-02-08
... Douglas Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F, MD-10-10F, MD-10-30F, MD-11, and MD-11F Airplanes AGENCY: Federal Aviation... airworthiness directive (AD) for certain Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC- 10A and...
Directory of Open Access Journals (Sweden)
D.D. Lestiani
2011-08-01
Full Text Available Urbanization and industrial growth have deteriorated air quality and are major cause to air pollution. Air pollution through fine and ultra-fine particles is a serious threat to human health. The source of air pollution must be known quantitatively by elemental characterization, in order to design the appropriate air quality management. The suitable methods for analysis the airborne particulate matter such as nuclear analytical techniques are hardly needed to solve the air pollution problem. The objectives of this study are to apply the nuclear analytical techniques to airborne particulate samples collected in Bandung, to assess the accuracy and to ensure the reliable of analytical results through the comparison of instrumental neutron activation analysis (INAA and particles induced X-ray emission (PIXE. Particle samples in the PM2.5 and PM2.5-10 ranges have been collected in Bandung twice a week for 24 hours using a Gent stacked filter unit. The result showed that generally there was a systematic difference between INAA and PIXE results, which the values obtained by PIXE were lower than values determined by INAA. INAA is generally more sensitive and reliable than PIXE for Na, Al, Cl, V, Mn, Fe, Br and I, therefore INAA data are preffered, while PIXE usually gives better precision than INAA for Mg, K, Ca, Ti and Zn. Nevertheless, both techniques provide reliable results and complement to each other. INAA is still a prospective method, while PIXE with the special capabilities is a promising tool that could contribute and complement the lack of NAA in determination of lead, sulphur and silicon. The combination of INAA and PIXE can advantageously be used in air pollution studies to extend the number of important elements measured as key elements in source apportionment.
Stochastic Methods Applied to Power System Operations with Renewable Energy: A Review
Energy Technology Data Exchange (ETDEWEB)
Zhou, Z. [Argonne National Lab. (ANL), Argonne, IL (United States); Liu, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Electric Reliability Council of Texas (ERCOT), Austin, TX (United States); Botterud, A. [Argonne National Lab. (ANL), Argonne, IL (United States)
2016-08-01
Renewable energy resources have been rapidly integrated into power systems in many parts of the world, contributing to a cleaner and more sustainable supply of electricity. Wind and solar resources also introduce new challenges for system operations and planning in terms of economics and reliability because of their variability and uncertainty. Operational strategies based on stochastic optimization have been developed recently to address these challenges. In general terms, these stochastic strategies either embed uncertainties into the scheduling formulations (e.g., the unit commitment [UC] problem) in probabilistic forms or develop more appropriate operating reserve strategies to take advantage of advanced forecasting techniques. Other approaches to address uncertainty are also proposed, where operational feasibility is ensured within an uncertainty set of forecasting intervals. In this report, a comprehensive review is conducted to present the state of the art through Spring 2015 in the area of stochastic methods applied to power system operations with high penetration of renewable energy. Chapters 1 and 2 give a brief introduction and overview of power system and electricity market operations, as well as the impact of renewable energy and how this impact is typically considered in modeling tools. Chapter 3 reviews relevant literature on operating reserves and specifically probabilistic methods to estimate the need for system reserve requirements. Chapter 4 looks at stochastic programming formulations of the UC and economic dispatch (ED) problems, highlighting benefits reported in the literature as well as recent industry developments. Chapter 5 briefly introduces alternative formulations of UC under uncertainty, such as robust, chance-constrained, and interval programming. Finally, in Chapter 6, we conclude with the main observations from our review and important directions for future work.
The Global Survey Method Applied to Ground-level Cosmic Ray Measurements
Belov, A.; Eroshenko, E.; Yanke, V.; Oleneva, V.; Abunin, A.; Abunina, M.; Papaioannou, A.; Mavromichalaki, H.
2018-04-01
The global survey method (GSM) technique unites simultaneous ground-level observations of cosmic rays in different locations and allows us to obtain the main characteristics of cosmic-ray variations outside of the atmosphere and magnetosphere of Earth. This technique has been developed and applied in numerous studies over many years by the Institute of Terrestrial Magnetism, Ionosphere and Radiowave Propagation (IZMIRAN). We here describe the IZMIRAN version of the GSM in detail. With this technique, the hourly data of the world-wide neutron-monitor network from July 1957 until December 2016 were processed, and further processing is enabled upon the receipt of new data. The result is a database of homogeneous and continuous hourly characteristics of the density variations (an isotropic part of the intensity) and the 3D vector of the cosmic-ray anisotropy. It includes all of the effects that could be identified in galactic cosmic-ray variations that were caused by large-scale disturbances of the interplanetary medium in more than 50 years. These results in turn became the basis for a database on Forbush effects and interplanetary disturbances. This database allows correlating various space-environment parameters (the characteristics of the Sun, the solar wind, et cetera) with cosmic-ray parameters and studying their interrelations. We also present features of the coupling coefficients for different neutron monitors that enable us to make a connection from ground-level measurements to primary cosmic-ray variations outside the atmosphere and the magnetosphere. We discuss the strengths and weaknesses of the current version of the GSM as well as further possible developments and improvements. The method developed allows us to minimize the problems of the neutron-monitor network, which are typical for experimental physics, and to considerably enhance its advantages.
Multicriterial Hierarchy Methods Applied in Consumption Demand Analysis. The Case of Romania
Directory of Open Access Journals (Sweden)
Constantin Bob
2008-03-01
Full Text Available The basic information for computing the quantitative statistical indicators, that characterize the demand of industrial products and services are collected by the national statistics organizations, through a series of statistical surveys (most of them periodical and partial. The source for data we used in the present paper is an statistical investigation organized by the National Institute of Statistics, "Family budgets survey" that allows to collect information regarding the households composition, income, expenditure, consumption and other aspects of population living standard. In 2005, in Romania, a person spent monthly in average 391,2 RON, meaning about 115,1 Euros for purchasing the consumed food products and beverage, as well as non-foods products, services, investments and other taxes. 23% of this sum was spent for purchasing the consumed food products and beverages, 21.6% of the total sum was spent for purchasing non-food goods and 18,1% for payment of different services. There is a discrepancy between the different development regions in Romania, regarding total households expenditure composition. For this reason, in the present paper we applied statistical methods for ranking the various development regions in Romania, using the share of householdsí expenditure on categories of products and services as ranking criteria.
Applying the Communicative Methodic in Learning Lithuanian as a Second Language
Directory of Open Access Journals (Sweden)
Vaida Buivydienė
2011-04-01
Full Text Available One of the strengths of European countries is their multilingual nature. That was stressed by the European Council during different international projects. Every citizen of Europe should be given the opportunity to learn languages life long, as languages open new perspectives in the modern world. Besides, learning languages brings tolerance and understanding to people from different cultures. The article presents the idea, based on the experience of foreign language teaching, that communicative method in learning languages should be applied also to Lithuanian as a foreign language teaching. According to international SOCRATES exchange programme, every year a lot of students and teachers from abroad come to Lithuanian Higher Schools (VGTU included. They should also be provided with opportunities to gain the best language learning, cultural and educational experience. Most of the students that came to VGTU pointed out Lithuanian language learning being one of the subjects to be chosen. That leads to organizing interesting and useful short-lasting Lithuanian language courses. The survey carried in VGTU and the analysis of the materials gathered leads to the conclusion that the communicative approach in language teaching is the best to cater the needs and interests of the learners to master the survival Lithuanian.
A new method of identifying target groups for pronatalist policy applied to Australia.
Directory of Open Access Journals (Sweden)
Mengni Chen
Full Text Available A country's total fertility rate (TFR depends on many factors. Attributing changes in TFR to changes of policy is difficult, as they could easily be correlated with changes in the unmeasured drivers of TFR. A case in point is Australia where both pronatalist effort and TFR increased in lock step from 2001 to 2008 and then decreased. The global financial crisis or other unobserved confounders might explain both the reducing TFR and pronatalist incentives after 2008. Therefore, it is difficult to estimate causal effects of policy using econometric techniques. The aim of this study is to instead look at the structure of the population to identify which subgroups most influence TFR. Specifically, we build a stochastic model relating TFR to the fertility rates of various subgroups and calculate elasticity of TFR with respect to each rate. For each subgroup, the ratio of its elasticity to its group size is used to evaluate the subgroup's potential cost effectiveness as a pronatalist target. In addition, we measure the historical stability of group fertility rates, which measures propensity to change. Groups with a high effectiveness ratio and also high propensity to change are natural policy targets. We applied this new method to Australian data on fertility rates broken down by parity, age and marital status. The results show that targeting parity 3+ is more cost-effective than lower parities. This study contributes to the literature on pronatalist policies by investigating the targeting of policies, and generates important implications for formulating cost-effective policies.
A new method of identifying target groups for pronatalist policy applied to Australia.
Chen, Mengni; Lloyd, Chris J; Yip, Paul S F
2018-01-01
A country's total fertility rate (TFR) depends on many factors. Attributing changes in TFR to changes of policy is difficult, as they could easily be correlated with changes in the unmeasured drivers of TFR. A case in point is Australia where both pronatalist effort and TFR increased in lock step from 2001 to 2008 and then decreased. The global financial crisis or other unobserved confounders might explain both the reducing TFR and pronatalist incentives after 2008. Therefore, it is difficult to estimate causal effects of policy using econometric techniques. The aim of this study is to instead look at the structure of the population to identify which subgroups most influence TFR. Specifically, we build a stochastic model relating TFR to the fertility rates of various subgroups and calculate elasticity of TFR with respect to each rate. For each subgroup, the ratio of its elasticity to its group size is used to evaluate the subgroup's potential cost effectiveness as a pronatalist target. In addition, we measure the historical stability of group fertility rates, which measures propensity to change. Groups with a high effectiveness ratio and also high propensity to change are natural policy targets. We applied this new method to Australian data on fertility rates broken down by parity, age and marital status. The results show that targeting parity 3+ is more cost-effective than lower parities. This study contributes to the literature on pronatalist policies by investigating the targeting of policies, and generates important implications for formulating cost-effective policies.
A Study of the Efficiency of Spatial Indexing Methods Applied to Large Astronomical Databases
Donaldson, Tom; Berriman, G. Bruce; Good, John; Shiao, Bernie
2018-01-01
Spatial indexing of astronomical databases generally uses quadrature methods, which partition the sky into cells used to create an index (usually a B-tree) written as database column. We report the results of a study to compare the performance of two common indexing methods, HTM and HEALPix, on Solaris and Windows database servers installed with a PostgreSQL database, and a Windows Server installed with MS SQL Server. The indexing was applied to the 2MASS All-Sky Catalog and to the Hubble Source catalog. On each server, the study compared indexing performance by submitting 1 million queries at each index level with random sky positions and random cone search radius, which was computed on a logarithmic scale between 1 arcsec and 1 degree, and measuring the time to complete the query and write the output. These simulated queries, intended to model realistic use patterns, were run in a uniform way on many combinations of indexing method and indexing level. The query times in all simulations are strongly I/O-bound and are linear with number of records returned for large numbers of sources. There are, however, considerable differences between simulations, which reveal that hardware I/O throughput is a more important factor in managing the performance of a DBMS than the choice of indexing scheme. The choice of index itself is relatively unimportant: for comparable index levels, the performance is consistent within the scatter of the timings. At small index levels (large cells; e.g. level 4; cell size 3.7 deg), there is large scatter in the timings because of wide variations in the number of sources found in the cells. At larger index levels, performance improves and scatter decreases, but the improvement at level 8 (14 min) and higher is masked to some extent in the timing scatter caused by the range of query sizes. At very high levels (20; 0.0004 arsec), the granularity of the cells becomes so high that a large number of extraneous empty cells begin to degrade
Directory of Open Access Journals (Sweden)
Muh. Zakiyullah Romdlony
2012-07-01
Full Text Available Well-regulated DC bus voltage is the important point to guarantee the power demand in hybrid vehicle applications. Voltage regulation can be achieved with control method that build switching signal on DC-DC converter. This paper describes design and small scale experimental results of bus voltage regulation control of the DC-DC bidirectional converter with battery and supercapacitor as energy source. The control system consists of two control loops, the outer loop that get DC bus voltage feedback using PI anti-windup back calculation control method. This outer loop will generate a reference current for the inner loop that implement hysteresis control. The inner control loop will compare that reference curent with the source current obtained from the current sensor. Simulation and experimental results show that bus voltage is well-regulated under the load changes with 1% voltage ripple.
Directory of Open Access Journals (Sweden)
Bezkrovnaya Yulia
2015-08-01
Full Text Available The article presents the results of empiric justification of the structure of methods and techniques of marketing research of consumer decisions, applied by the world and Ukrainian research companies.
TOPOLOGICAL REVIEW AND ANALYSIS OF DC-DC BOOST CONVERTERS
Directory of Open Access Journals (Sweden)
V. INDRA GANDHI
2017-06-01
Full Text Available DC voltage boost up is essential in numerous applications; especially considering Photovoltaic (PV based renewable power generation system. The conventional DC-DC boost converter is the most admired configuration for this scheme, even if the converter efficiency is restricted at duty cycle near to maximum value. In order to find solution to the problem and improve its conversion capability, many converter configurations have been implemented so far. With this circumstance, this research work proposes to give overview of a few most imperative research works related to DC-DC boost converters. Some configurations are covered and classified basically based on the application. The major benefits and disadvantages related to the available techniques are also briefly conveyed. At last, a proper evaluation is recognized among the important types of DC-DC boost converters in terms of efficiency, number of components, and stability.
Sterilization by negative and positive DC plasma with a micro discharge gap at atmospheric pressure
Li, Hua; Jiang, Lin-Xiu; Jiang, Yong-Rong; Zhu, Jian-Min; Chen, Zhen-Cheng
2017-11-01
A new needle-to-droplet electrode structure with a micro discharge gap (2 mm) was designed to achieve direct current (DC) discharge plasma in ambient air with the aim of using the plasma to sterilize liquids. Without using noble gases or an external air flow, we succeeded in generating both a negative and positive DC plasma at atmospheric pressure. The plasma was driven by a 0 to ‑20,000 V, 100 W DC power supply. A stainless steel needle with a tip diameter of ˜ 50μm and a 200-μL droplet of bacteria-containing liquid served as the electrodes. At atmospheric pressure and room temperature (23∘C), utilizing the negative DC plasma, the discharge time lasted 10 s; the results showed that the higher the discharge voltage, the more efficient the sterilization effect. Conversely, when we applied a voltage of ‑5.5 kV, we found that the sterilization effect was more efficient for longer discharge times. Our findings demonstrate that Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) can be killed in about 30 s. Our experiments show that our sterilization method required less time and was more efficient for positive than for negative DC plasma under the same conditions.
DEFF Research Database (Denmark)
Liu, Changjin; Xu, Dehong; Zhu, Nan
2013-01-01
Unbalanced grid voltage causes a large second-order harmonic current in the dc-link capacitors as well as dc-voltage fluctuation, which potentially will degrade the lifespan and reliability of the capacitors in voltage source converters. This paper proposes a novel dc-capacitor current control me...... grid voltage conditions. A modular implementation method of the proposed control strategy is developed for the DFIG controller. Finally, experiments are presented to validate the theoretical analysis....
Directory of Open Access Journals (Sweden)
Gunar Boye
2015-06-01
Full Text Available The axial heat transfer coefficient during flow boiling of n-hexane was measured using infrared thermography to determine the axial wall temperature in three geometrically similar annular gaps with different widths (s = 1.5 mm, s = 1 mm, s = 0.5 mm. During the design and evaluation process, the methods of statistical experimental design were applied. The following factors/parameters were varied: the heat flux q · = 30 − 190 kW / m 2 , the mass flux m · = 30 − 700 kg / m 2 s , the vapor quality x · = 0 . 2 − 0 . 7 , and the subcooled inlet temperature T U = 20 − 60 K . The test sections with gap widths of s = 1.5 mm and s = 1 mm had very similar heat transfer characteristics. The heat transfer coefficient increases significantly in the range of subcooled boiling, and after reaching a maximum at the transition to the saturated flow boiling, it drops almost monotonically with increasing vapor quality. With a gap width of 0.5 mm, however, the heat transfer coefficient in the range of saturated flow boiling first has a downward trend and then increases at higher vapor qualities. For each test section, two correlations between the heat transfer coefficient and the operating parameters have been created. The comparison also shows a clear trend of an increasing heat transfer coefficient with increasing heat flux for test sections s = 1.5 mm and s = 1.0 mm, but with increasing vapor quality, this trend is reversed for test section 0.5 mm.
A new method of identifying target groups for pronatalist policy applied to Australia
Chen, Mengni; Lloyd, Chris J.
2018-01-01
A country’s total fertility rate (TFR) depends on many factors. Attributing changes in TFR to changes of policy is difficult, as they could easily be correlated with changes in the unmeasured drivers of TFR. A case in point is Australia where both pronatalist effort and TFR increased in lock step from 2001 to 2008 and then decreased. The global financial crisis or other unobserved confounders might explain both the reducing TFR and pronatalist incentives after 2008. Therefore, it is difficult to estimate causal effects of policy using econometric techniques. The aim of this study is to instead look at the structure of the population to identify which subgroups most influence TFR. Specifically, we build a stochastic model relating TFR to the fertility rates of various subgroups and calculate elasticity of TFR with respect to each rate. For each subgroup, the ratio of its elasticity to its group size is used to evaluate the subgroup’s potential cost effectiveness as a pronatalist target. In addition, we measure the historical stability of group fertility rates, which measures propensity to change. Groups with a high effectiveness ratio and also high propensity to change are natural policy targets. We applied this new method to Australian data on fertility rates broken down by parity, age and marital status. The results show that targeting parity 3+ is more cost-effective than lower parities. This study contributes to the literature on pronatalist policies by investigating the targeting of policies, and generates important implications for formulating cost-effective policies. PMID:29425220
Non-destructive scanning for applied stress by the continuous magnetic Barkhausen noise method
Franco Grijalba, Freddy A.; Padovese, L. R.
2018-01-01
This paper reports the use of a non-destructive continuous magnetic Barkhausen noise technique to detect applied stress on steel surfaces. The stress profile generated in a sample of 1070 steel subjected to a three-point bending test is analyzed. The influence of different parameters such as pickup coil type, scanner speed, applied magnetic field and frequency band analyzed on the effectiveness of the technique is investigated. A moving smoothing window based on a second-order statistical moment is used to analyze the time signal. The findings show that the technique can be used to detect applied stress profiles.
Krylov Subspace and Multigrid Methods Applied to the Incompressible Navier-Stokes Equations
Vuik, C.; Wesseling, P.; Zeng, S.
1996-01-01
We consider numerical solution methods for the incompressible Navier-Stokes equations discretized by a finite volume method on staggered grids in general coordinates. We use Krylov subspace and multigrid methods as well as their combinations. Numerical experiments are carried out on a scalar and a vector computer. Robustness and efficiency of these methods are studied. It appears that good methods result from suitable combinations of GCR and multigrid methods.
Chen, Kai; Chen, Zhe; Sun, Zhigang; Zhang, Zhuqing; Ding, Dongbing; Ren, Shuangyi; Zuo, Yunfei
2014-01-01
Background Colon cancer has always been diagnosed at a late stage, which is associated with poor prognosis. The currently used serum tumor markers CEA and CA19-9 display low sensitivity and specificity and may not have diagnostic value in early stage colon cancer. Thus, there is an urgent need to identify novel serum biomarkers for use in the early detection of colon cancer. Methods In this study, the expression of DC-SIGN and DC-SIGNR in serum was detected by enzyme-linked immunosorbent assay (ELISA). DC-SIGN and DC-SIGNR expression was detected in cancer tissues by immunohistochemistry (IHC). Results The level of sDC-SIGN was lower in patients than in the healthy controls, while the level of sDC-SIGNR in patients was higher than in the healthy controls. Both sDC-SIGN and sDC-SIGNR had diagnostic significances for cancer patients, and the combined diagnosis of these two markers was higher than both of them alone. Furthermore, there were significant differences between both sDC-SIGN and sDC-SIGNR in stage I/II patients and the healthy controls. Moreover, high sDC-SIGN level was accompanied with the long survival time. Additionally, DC-SIGNR was negative in the cancer foci and matched normal colon tissues but was weakly positive between the cancer foci. DC-SIGN staining was faint in matched normal colon tissues, strong in the tumor stroma and the invasive margin of colon cancer tissues, and negatively correlated with the sDC-SIGN level in serum from the same patient. Interestingly, the percent survival of patients with a DC-SIGN mean density of>0.001219 (the upper 95% confidence interval of matched normal colon tissues) was higher than for all other patients. Conclusion DC-SIGN and DC-SIGNR are blood-based molecular markers that can potentially be used for the diagnosis of early stage patients. Moreover, expression of DC-SIGN in serum and cancer tissues may affect the survival time for colon cancer patients. PMID:25504222
DEFF Research Database (Denmark)
Wang, Haojie; Han, Minxiao; Yan, Wenli
2016-01-01
for storage batteries in DC microgrids. The working principle of TIDC is analyzed, and the factors influencing the response rate based on the dual-loop constant voltage control for TIDC are discussed, and then the method of feed-forward control for TIDC is studied to improve the response rate for load...
International Nuclear Information System (INIS)
Li, Zeguang; Wang, Kan; Zhang, Xisi
2011-01-01
In traditional Monte Carlo method, the material properties in a certain cell are assumed to be constant, but this is no longer applicable in continuous varying materials where the material's nuclear cross-sections vary over the particle's flight path. So, three Monte Carlo methods, including sub stepping method, delta-tracking method and direct sampling method, are discussed in this paper to solve the problems with continuously varying materials. After the verification and comparison of these methods in 1-D models, the basic specialties of these methods are discussed and then we choose the delta-tracking method as the main method to solve the problems with continuously varying materials, especially 3-D problems. To overcome the drawbacks of the original delta-tracking method, an improved delta-tracking method is proposed in this paper to make this method more efficient in solving problems where the material's cross-sections vary sharply over the particle's flight path. To use this method in practical calculation, we implemented the improved delta-tracking method into the 3-D Monte Carlo code RMC developed by Department of Engineering Physics, Tsinghua University. Two problems based on Godiva system were constructed and calculations were made using both improved delta-tracking method and the sub stepping method, and the results proved the effects of improved delta-tracking method. (author)
The Density-Enthalpy Method Applied to Model Two–phase Darcy Flow
Ibrahim, D.
2012-01-01
In this thesis, we use a more recent method to numerically solve two-phase fluid flow problems. The method is developed at TNO and it is presented by Arendsen et al. in [1] for spatially homogeneous systems. We will refer to this method as the densityenthalpy method (DEM) because the
RF and dc desensitized electroexplosive device
Krainiak, John W.; Speaks, Paul D.; Cornett, Michael S.
1989-07-01
This patent application relates to electroexplosive devices (EEDs) such as detonators, blasting caps and squibs, in particular to a method and device for desensitizing EEDs to electromagnetic radiation and electrostatic charges with the added ability to desensitize the device to essentially dc currents. An insensitive electroexplosive device to electrically ignite explosive is disclosed. This device is inherently immune to radio frequency (RF) radiation, and also provides protection against dc or very low frequency RF induced by arcing. A central feature is use of zeners and capacitors to form a reactively balanced bridge circuit. When constructed in semiconductor form, as described in this application, the device is capable of incorporation in small caliber ordnance.
Manufacturing development of DC-10 advanced rudder
Cominsky, A.
1979-01-01
The design, manufacture, and ground test activities during development of production methods for an advanced composite rudder for the DC-10 transport aircraft are described. The advanced composite aft rudder is satisfactory for airline service and a cost saving in a full production manufacturing mode is anticipated.
Power Oscillations Damping in DC Microgrids
DEFF Research Database (Denmark)
Hamzeh, Mohsen; Ghafouri, Mohsen; Karimi, Houshang
2016-01-01
impedance loop is determined using small signal analysis and pole placement method. The Mesh analysis is employed to further study the stability of low-frequency modes of the overall dc microgrid. Moreover, based on the guardian map theorem, a robust stability analysis is carried out to determine...
Agent-based distributed hierarchical control of dc microgrid systems
DEFF Research Database (Denmark)
Meng, Lexuan; Vasquez, Juan Carlos; Guerrero, Josep M.
2014-01-01
In order to enable distributed control and management for microgrids, this paper explores the application of information consensus and local decisionmaking methods formulating an agent based distributed hierarchical control system. A droop controlled paralleled DC/DC converter system is taken...
International Nuclear Information System (INIS)
Rijssel, Jos van; Kuipers, Bonny W.M.; Erné, Ben H.
2014-01-01
A numerical inversion method known from the analysis of light scattering by colloidal dispersions is now applied to magnetization curves of ferrofluids. The distribution of magnetic particle sizes or dipole moments is determined without assuming that the distribution is unimodal or of a particular shape. The inversion method enforces positive number densities via a non-negative least squares procedure. It is tested successfully on experimental and simulated data for ferrofluid samples with known multimodal size distributions. The created computer program MINORIM is made available on the web. - Highlights: • A method from light scattering is applied to analyze ferrofluid magnetization curves. • A magnetic size distribution is obtained without prior assumption of its shape. • The method is tested successfully on ferrofluids with a known size distribution. • The practical limits of the method are explored with simulated data including noise. • This method is implemented in the program MINORIM, freely available online
Auxiliary resonant DC tank converter
Peng, Fang Z.
2000-01-01
An auxiliary resonant dc tank (ARDCT) converter is provided for achieving soft-switching in a power converter. An ARDCT circuit is coupled directly across a dc bus to the inverter to generate a resonant dc bus voltage, including upper and lower resonant capacitors connected in series as a resonant leg, first and second dc tank capacitors connected in series as a tank leg, and an auxiliary resonant circuit comprising a series combination of a resonant inductor and a pair of auxiliary switching devices. The ARDCT circuit further includes first clamping means for holding the resonant dc bus voltage to the dc tank voltage of the tank leg, and second clamping means for clamping the resonant dc bus voltage to zero during a resonant period. The ARDCT circuit resonantly brings the dc bus voltage to zero in order to provide a zero-voltage switching opportunity for the inverter, then quickly rebounds the dc bus voltage back to the dc tank voltage after the inverter changes state. The auxiliary switching devices are turned on and off under zero-current conditions. The ARDCT circuit only absorbs ripples of the inverter dc bus current, thus having less current stress. In addition, since the ARDCT circuit is coupled in parallel with the dc power supply and the inverter for merely assisting soft-switching of the inverter without participating in real dc power transmission and power conversion, malfunction and failure of the tank circuit will not affect the functional operation of the inverter; thus a highly reliable converter system is expected.
Dhakal, Tilak R.; Zhang, Duan Z.
2016-11-01
Using a simple one-dimensional shock problem as an example, the present paper investigates numerical properties of the original material point method (MPM), the generalized interpolation material point (GIMP) method, the convected particle domain interpolation (CPDI) method, and the dual domain material point (DDMP) method. For a weak isothermal shock of ideal gas, the MPM cannot be used with accuracy. With a small number of particles per cell, GIMP and CPDI produce reasonable results. However, as the number of particles increases the methods fail to converge and produce pressure spikes. The DDMP method behaves in an opposite way. With a small number of particles per cell, DDMP results are unsatisfactory. As the number of particles increases, the DDMP results converge to correct solutions, but the large number of particles needed for convergence makes the method very expensive to use in these types of shock wave problems in two- or three-dimensional cases. The cause for producing the unsatisfactory DDMP results is identified. A simple improvement to the method is introduced by using sub-points. With this improvement, the DDMP method produces high quality numerical solutions with a very small number of particles. Although in the present paper, the numerical examples are one-dimensional, all derivations are for multidimensional problems. With the technique of approximately tracking particle domains of CPDI, the extension of this sub-point method to multidimensional problems is straightforward. This new method preserves the conservation properties of the DDMP method, which conserves mass and momentum exactly and conserves energy to the second order in both spatial and temporal discretizations.
DC-Link Protection and Control in Modular Uninterruptible Power Supply
DEFF Research Database (Denmark)
Lu, Jinghang; Savaghebi, Mehdi; Guan, Yajuan
2018-01-01
In this paper, a DC-link voltage protection (DCVP) control method is proposed to address the DC-link overvoltage issue due to power back-feeding in parallel Uninterruptible Power Supply (UPS) system. The proposed control method is able to protect the inverter against the excessive DC-link voltage...
Directory of Open Access Journals (Sweden)
Vina Agustiana
2017-12-01
Full Text Available Four Square Writing Method is a writing method which helps students in organizing concept to write by using a graphic organizer. This study aims to examine the influence of applying FSWM in combination of product and process based approaches to teaching writing discussion texts toward students’ writing skill, the teaching-learning writing process and the students’ attitude toward the implementation of the writing method. This study applies a mixed-method through applying an embedded design. 26 EFL university students of a private university in West Java, Indonesia, are involved in the study. There are 3 kinds of instrument used, namely tests (pre and post-test, field notes, and questionnaires. Data taken from students’ writing test are analyzed statistically to identify the influence of applying the writing method toward students’ writing skill; data taken from field notes are analyzed qualitatively to examine the learning writing activities at the time the writing method is implemented; and data taken from questionnaires are analyzed descriptive statistic to explore students’ attitude toward the implementation of the writing method. Regarding the result of paired t-test, the writing method is effective in improving students’ writing skill since level of significant (two-tailed is less than alpha (0.000<0.05. Furthermore, the result taken from field notes shows that each steps applied and graphic organizer used in the writing method lead students to compose discussion texts which meet a demand of genre. In addition, regard with the result taken from questionnaire, the students show highly positive attitude toward the treatment since the mean score is 4.32.
A global method for calculating plant CSR ecological strategies applied across biomes world-wide
Pierce, S.; Negreiros, D.; Cerabolini, B.E.L.; Kattge, J.; Díaz, S.; Kleyer, M.; Shipley, B.; Wright, S.J.; Soudzilovskaia, N.A.; Onipchenko, V.G.; van Bodegom, P.M.; Frenette-Dussault, C.; Weiher, E.; Pinho, B.X.; Cornelissen, J.H.C.; Grime, J.P.; Thompson, K.; Hunt, R.; Wilson, P.J.; Buffa, G.; Nyakunga, O.C.; Reich, P.B.; Caccianiga, M.; Mangili, F.; Ceriani, R.M.; Luzzaro, A.; Brusa, G.; Siefert, A.; Barbosa, N.P.U.; Chapin III, F.S.; Cornwell, W.K.; Fang, Jingyun; Wilson Fernandez, G.; Garnier, E.; Le Stradic, S.; Peñuelas, J.; Melo, F.P.L.; Slaviero, A.; Tabarrelli, M.; Tampucci, D.
2017-01-01
Competitor, stress-tolerator, ruderal (CSR) theory is a prominent plant functional strategy scheme previously applied to local floras. Globally, the wide geographic and phylogenetic coverage of available values of leaf area (LA), leaf dry matter content (LDMC) and specific leaf area (SLA)
Ossenkopf, V.; Krips, M.; Stutzki, J.
Context. The Delta-variance analysis is an efficient tool for measuring the structural scaling behaviour of interstellar turbulence in astronomical maps. It has been applied both to simulations of interstellar turbulence and to observed molecular cloud maps. In Paper I we proposed essential
High gain high efficiency resonant DC-DC converter
Shang, Fei
Low voltage power sources have played an important role in applications such as automotive system, renewable energy power generation and so on, where require a high gain DC-DC step-up converter. The converter is going to sustain a very high input current which can bring many design challenges in the existing topologies, such as high component current stress and power loss, complex and costly design for magnetic components, high input current ripple, etc. A new topology of high gain DCDC step-up converter proposed in this dissertation. The topology has many merits such as high gain capability, high efficiency, low components stress and requirement of the transformer, simple topology with less number of active switching devices, and easy to control. The dissertation carries out theoretical analysis of the proposed topology under different operating modes and the voltage gain has been deduced for each mode. The design of circuit components has been well studied, including the power devices current stress and power, the selection of transformer turns-ratio, the design method of the resonant tank and input current ripple. System dynamic state-space models are acquired by using generalized averaging method. Small signal model of the converter is achieved by linearization of the dynamic model around the operating points. The stability study indicates that the open loop system is stable at all operating points, except some operating points containing RHP zeros which can cause closed loop system unstable. The parameter sensitivity study shows that the system transfer function is not greatly affected by the variation of the leakage inductance and load resistance. A design of PI controller is implemented to achieve the output voltage regulation. Simulations have been carried out to validate the circuit operation and support the design analysis. A 2kW prototype has been built for experimental testing. The experimental results are in a good agreement with the theoretical
Brief analysis of Jiangsu grid security and stability based on multi-infeed DC index in power system
Zhang, Wenjia; Wang, Quanquan; Ge, Yi; Huang, Junhui; Chen, Zhengfang
2018-02-01
The impact of Multi-infeed HVDC has gradually increased to security and stability operating in Jiangsu power grid. In this paper, an appraisal method of Multi-infeed HVDC power grid security and stability is raised with Multi-Infeed Effective Short Circuit Ratio, Multi-Infeed Interaction Factor and Commutation Failure Immunity Index. These indices are adopted in security and stability simulating calculation of Jiangsu Multi-infeed HVDC system. The simulation results indicate that Jiangsu power grid is operating with a strong DC system. It has high level of power grid security and stability, and meet the safety running requirements. Jinpin-Suzhou DC system is located in the receiving end with huge capacity, which is easily leading to commutation failure of the transmission line. In order to resolve this problem, dynamic reactive power compensation can be applied in power grid near Jinpin-Suzhou DC system. Simulation result shows this method is feasible to commutation failure.
Jalaiah, K.; Vijaya Babu, K.; Chandra mouli, K.; Subba Rao, P. S. V.
2018-04-01
The Zr and Cu co-substituted Ni0.5Zn0.5Fe2O4 ferrite nanoparticles have been synthesized by the sol-gel auto combustion method. The XRD patterns confirmed single phase cubic spinel structure for present ferrite systems. The substitution of co-dopants in the spinel structure initially decreases the lattice parameter from x = 0.00 to 0.08 and thereafter increases and the same tendency reflecting in cell volume. The DC resistivity was initially increased later followed the decreasing trend; however the drift mobility of all ferrite samples appears to be in opposite phenomenon to DC resistivity. The saturation magnetization and net magnetic moments of all ferrite samples are decreasing with increasing dopant concentration. The coercive field and Y-K angles are increased with dopant concentration. The initial permeability of all samples is decreased with increasing dopant concentration. The Q-Factor for all samples shows the narrow frequency band with increasing frequency.
Evaluation of Two Fitting Methods Applied for Thin-Layer Drying of Cape Gooseberry Fruits
Directory of Open Access Journals (Sweden)
Erkan Karacabey
Full Text Available ABSTRACT Drying data of cape gooseberry was used to compare two fitting methods: namely 2-step and 1-step methods. Literature data was also used to confirm the results. To demonstrate the applicability of these methods, two primary models (Page, Two-term-exponential were selected. Linear equation was used as secondary model. As well-known from the previous modelling studies on drying, 2-step method required at least two regressions: One is primary model and one is secondary (if you have only one environmental condition such as temperature. On the other hand, one regression was enough for 1-step method. Although previous studies on kinetic modelling of drying of foods were based on 2-step method, this study indicated that 1-step method may also be a good alternative with some advantages such as drawing an informative figure and reducing time of calculations.
Deadbeat control of power leveling unit with bidirectional buck/boost DC/DC converter
Hamasaki, Shin-ichi; Mukai, Ryosuke; Yano, Yoshihiro; Tsuji, Mineo
2014-01-01
As a distributed generation system increases, a stable power supply becomes difficult. Thus control of power leveling (PL) unit is required to maintain the balance of power flow for irregular power generation. The unit is required to respond to change of voltage and bidirectional power flow. So the bidirectional buck/boost DC/DC converter is applied for the control of PL unit in this research. The PL unit with Electric double-layer capacitor (EDLC) is able to absorb change of power, and it is...
Kodama, Shinya; Hori, Yoichi
It is well-known that the separately-excited DC motor has effective torque (current) reduction characteristics in response to rapid increase in the rotational speed of the motor. These characteristics have been utilized in adhesion control of electric railway trains with separately-excited DC motor. Up to now, we have proposed a new skid prevention method for EVs, utilizing these characteristics and have made experiments with the hardware skid simulator “Motor-Generator setup”. In this paper, we applied this skid prevention control to our new vehicle “UOT CADWELL EV" equipped with BLDC motors and showed its effectiveness.
Masuda, Akihiro; Nishikawa, Toshio
2014-08-01
The distribution of dendritic cells (DCs) expressing DC-specific ICAM-3-grabbing non-integrin (DC-SIGN, CD209) and the morphological interaction of DC-SIGN⁺ DCs with other cells, especially B cells, in tonsillar and other lymphoid tissues were investigated by multiple immunohistochemistry (IHC) using the graphics editing program Photoshop, which enabled staining with 4 or more antibodies in formalin-fixed paraffin sections. Images obtained by repetition of conventional IHC using diaminobenzidine color development in a tissue section were processed on Photoshop for multiple staining. DC-SIGN⁺ DCs were present in the area around the lymphoid follicles and formed a DC-SIGN⁺ DC-rich area, and these cells contacted not only T cells, fascin⁺ DCs, and blood vessels but also several subsets of B cells simultaneously, including naïve and memory B cells. DC-SIGN⁺ DCs may play an important role in the regulation of the immune response mediated by not only T cells but also B cells. The multiple IHC method introduced in the present study is a simple and useful method for analyzing details of complex structures. Because this method can be applied to routinely processed paraffin sections with conventional IHC with diaminobenzidine, it can be applied to a wide variety of archival specimens.
International Nuclear Information System (INIS)
Poupeau, G.; Soliani Junior, E.
1988-01-01
This article discuss some applications of the 'nuclear tracks method' in geochronology, geochemistry and geophysic. In geochronology, after rapid presentation of the dating principles by 'Fission Track' and the kinds of geological events mensurable by this method, is showed some application in metallogeny and in petroleum geolocy. In geochemistry the 'fission tracks' method utilizations are related with mining prospecting and uranium prospecting. In geophysics an important application is the earthquake prevision, through the Ra 222 emanations continous control. (author) [pt
The development of a curved beam element model applied to finite elements method
International Nuclear Information System (INIS)
Bento Filho, A.
1980-01-01
A procedure for the evaluation of the stiffness matrix for a thick curved beam element is developed, by means of the minimum potential energy principle, applied to finite elements. The displacement field is prescribed through polynomial expansions, and the interpolation model is determined by comparison of results obtained by the use of a sample of different expansions. As a limiting case of the curved beam, three cases of straight beams, with different dimensional ratios are analised, employing the approach proposed. Finally, an interpolation model is proposed and applied to a curved beam with great curvature. Desplacements and internal stresses are determined and the results are compared with those found in the literature. (Author) [pt
Applying formal method to design of nuclear power plant embedded protection system
International Nuclear Information System (INIS)
Kim, Jin Hyun; Kim, Il Gon; Sung, Chang Hoon; Choi, Jin Young; Lee, Na Young
2001-01-01
Nuclear power embedded protection systems is a typical safety-critical system, which detects its failure and shutdowns its operation of nuclear reactor. These systems are very dangerous so that it absolutely requires safety and reliability. Therefore nuclear power embedded protection system should fulfill verification and validation completely from the design stage. To develop embedded system, various V and V method have been provided and especially its design using Formal Method is studied in other advanced country. In this paper, we introduce design method of nuclear power embedded protection systems using various Formal-Method in various respect following nuclear power plant software development guideline
Dam, A. van; Zegeling, P.A.
2006-01-01
In this paper we describe a one-dimensional adaptive moving mesh method and its application to hyperbolic conservation laws from magnetohydrodynamics (MHD). The method is robust, because it employs automatic control of mesh adaptation when a new model is considered, without manually-set
Statistical methods applied to gamma-ray spectroscopy algorithms in nuclear security missions.
Fagan, Deborah K; Robinson, Sean M; Runkle, Robert C
2012-10-01
Gamma-ray spectroscopy is a critical research and development priority to a range of nuclear security missions, specifically the interdiction of special nuclear material involving the detection and identification of gamma-ray sources. We categorize existing methods by the statistical methods on which they rely and identify methods that have yet to be considered. Current methods estimate the effect of counting uncertainty but in many cases do not address larger sources of decision uncertainty, which may be significantly more complex. Thus, significantly improving algorithm performance may require greater coupling between the problem physics that drives data acquisition and statistical methods that analyze such data. Untapped statistical methods, such as Bayes Modeling Averaging and hierarchical and empirical Bayes methods, could reduce decision uncertainty by rigorously and comprehensively incorporating all sources of uncertainty. Application of such methods should further meet the needs of nuclear security missions by improving upon the existing numerical infrastructure for which these analyses have not been conducted. Copyright © 2012 Elsevier Ltd. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Kiedrowski, Brian C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2014-03-11
The goals of this project are to develop Monte Carlo radiation transport methods and simulation software for engineering analysis that are robust, efficient and easy to use; and provide computational resources to assess and improve the predictive capability of radiation transport methods and nuclear data.
T2-01 A Method for Prioritizing Chemical Hazards in Food applied to Antibiotics
Asselt, van E.D.; Spiegel, van der M.; Noordam, M.Y.; Pikkemaat, M.G.; Fels, van der H.J.
2014-01-01
Introduction: Part of risk based control is the prioritization of hazard-food combinations for monitoring food safety. There are currently many methods for ranking microbial hazards ranging from quantitative to qualitative methods, but there is hardly any information available for prioritizing
A New Machine Classification Method Applied to Human Peripheral Blood Leukocytes.
Rorvig, Mark E.; And Others
1993-01-01
Discusses pattern classification of images by computer and describes the Two Domain Method in which expert knowledge is acquired using multidimensional scaling of judgments of dissimilarities and linear mapping. An application of the Two Domain Method that tested its power to discriminate two patterns of human blood leukocyte distribution is…
Studying the properties of Variational Data Assimilation Methods by Applying a Set of Test-Examples
DEFF Research Database (Denmark)
Thomsen, Per Grove; Zlatev, Zahari
2007-01-01
data assimilation methods are used. The main idea, on which the variational data assimilation methods are based, is pretty general. A functional is formed by using a weighted inner product of differences of model results and measurements. The value of this functional is to be minimized. Forward...
The quasi-exactly solvable potentials method applied to the three-body problem
International Nuclear Information System (INIS)
Chafa, F.; Chouchaoui, A.; Hachemane, M.; Ighezou, F.Z.
2007-01-01
The quasi-exactly solved potentials method is used to determine the energies and the corresponding exact eigenfunctions for three families of potentials playing an important role in the description of interactions occurring between three particles of equal mass. The obtained results may also be used as a test in evaluating the performance of numerical methods
International Nuclear Information System (INIS)
Clarisse, J.M.; Boudesocque-Dubois, C.; Leidinger, J.P.; Willien, J.L.
2006-01-01
A linear perturbation computation method is used to compute hydrodynamic instability growth in model implosions of inertial confinement fusion direct-drive and indirect-drive designed targets. Accurate descriptions of linear perturbation evolutions for Legendre mode numbers up to several hundreds have thus been obtained in a systematic way, motivating further improvements of the physical modeling currently handled by the method. (authors)
Heterogeneity among violence-exposed women: applying person-oriented research methods.
Nurius, Paula S; Macy, Rebecca J
2008-03-01
Variability of experience and outcomes among violence-exposed people pose considerable challenges toward developing effective prevention and treatment protocols. To address these needs, the authors present an approach to research and a class of methodologies referred to as person oriented. Person-oriented tools support assessment of meaningful patterns among people that distinguish one group from another, subgroups for whom different interventions are indicated. The authors review the conceptual base of person-oriented methods, outline their distinction from more familiar variable-oriented methods, present descriptions of selected methods as well as empirical applications of person-oriented methods germane to violence exposure, and conclude with discussion of implications for future research and translation between research and practice. The authors focus on violence against women as a population, drawing on stress and coping theory as a theoretical framework. However, person-oriented methods hold utility for investigating diversity among violence-exposed people's experiences and needs across populations and theoretical foundations.