Theory, analysis and applications of the operation of the superconducting transformer supplying a direct current to a non-dissipative superconducting charge circuit

International Nuclear Information System (INIS)

Sole, J.

1967-01-01

The author derives the very simple equations governing the operation of a transformer with superconducting windings supplying direct current to a non-dissipative superconducting charge circuit. An analysis of the various possible modes of operation with direct or slowly varying current raises the problem of the magnetic core. The study. leads to a conclusion which a priori might be surprising: the elimination of the magnetic core and the use of a primary super-conductor. An example of a possible realization of such a transformer is given as an indication, and the present prospects for different applications are considered. (author) [fr

Zener diode controls switching of large direct currents

Science.gov (United States)

1965-01-01

High-current zener diode is connected in series with the positive input terminal of a dc supply to block the flow of direct current until a high-frequency control signal is applied across the zener diode. This circuit controls the switching of large dc signals.

TEXT poloidal coil systems power supplies

International Nuclear Information System (INIS)

Hutchins, S.H.; Brower, D.F.

1977-01-01

TEXT is a convertional iron core tokamak which will have a toroidal field of 3.0 Tesla produced by room temperature copper coils and a maximum plasma current pulse of 400 kA induced by a 40 turn Ohmic Heating coil. The major radius is 100 cm and the minor radius of the plasma is 28 cm. The machine is intended for basic research in tokamak plasma physics and atomic physics and is designed primarily to provide a stable hot plasma, extremely good diagnostic access, and reliable operation. The discharge pulse length will be 300 msec and the repetition period 120 seconds. Power for the toroidal field coils and for the ohmic heating supply is provided by a 100 MVA energy storage alternator. The vertical field, horizontal field, fast positioning, and discharge cleaning power supply systems are powered from the Tokamak Laboratory power mains. The ohmic heating power system consists of an SCR controlled premagnetizing supply and commutation circuit, the main ohmic heating capacitor bank to provide plasma breakdown and current rise, and an SCR controlled power supply which sustains plasma current during the 300 ms pulse. The vertical field power system uses a small capacitor bank and an SCR controlled supply. The horizontal field has a reversible SCR controlled supply, and the fast positioning coils are powered by bipolar output transistor controlled supplies. This paper describes the loads, required wave forms, and the specifications for these power supply systems

Power supply system for KSTAR neutral beam injector

Energy Technology Data Exchange (ETDEWEB)

Cho, W., E-mail: franciscocho@nfri.re.kr; Bae, Y.S.; Han, W.S.; Jeong, J.H.; Kim, J.S.; Park, H.T.; Yang, H.L.; Oh, Y.K.; Kwak, J.G.

2015-10-15

Highlights: • The power supply system in KSTAR NBI consists of DC power supplies for ion source. • For operation NBI, DC High Voltage based on the low voltage transformer with chopper. • The surge absorber near the ion source limit the energy deposited to accelerator grid. - Abstract: The power supply system in KSTAR neutral beam injector consists of low voltage and high current DC power supplies for plasma generator of ion source and high voltage and high current DC power supply for accelerator grid system. The arc discharge is initiated by an arc power supply supplying the arc voltage between the chamber wall and 12 filaments which are heated by individual filament power supply. The negative output of arc power supply is common to each positive output of 12 filament power supplies. To interrupt the arc discharging for the fault condition of the arc current unbalance, DCCT current monitor is placed at the positive output cable of the filament power supply. The plasma grid (G1) power supply has the maximum capability of 120 kV/70 A which consists of low voltage regulator with IGBT-switched chopper array system for the voltage control in unit of 600 V and the high voltage rectified transformers to supply DC voltage of 20 kV, 30 kV, and 50 kV. The output voltage of the G1 power supply is also connected to the input of the voltage divider system which supplies the gradient voltage to the gradient grid (G2) in the range of 80–90% of G1 voltage by changing tap of winding resistors in unit of 1%. The charged G1 voltage is turned on and off by the high voltage switch (HVS) system consisting of MOSFET fast semiconductor switches which can immediately be opened less than 1 μs when the ion source grid breakdown occurs. The decelerating grid (G3) power supply is inverter system using capacitor-charge power supply to supply maximum −5 kV/5 A. The important component in power supply system is the surge absorber near the ion source to limit the arc energy deposited to

Power supply system for KSTAR neutral beam injector

International Nuclear Information System (INIS)

Cho, W.; Bae, Y.S.; Han, W.S.; Jeong, J.H.; Kim, J.S.; Park, H.T.; Yang, H.L.; Oh, Y.K.; Kwak, J.G.

2015-01-01

Highlights: • The power supply system in KSTAR NBI consists of DC power supplies for ion source. • For operation NBI, DC High Voltage based on the low voltage transformer with chopper. • The surge absorber near the ion source limit the energy deposited to accelerator grid. - Abstract: The power supply system in KSTAR neutral beam injector consists of low voltage and high current DC power supplies for plasma generator of ion source and high voltage and high current DC power supply for accelerator grid system. The arc discharge is initiated by an arc power supply supplying the arc voltage between the chamber wall and 12 filaments which are heated by individual filament power supply. The negative output of arc power supply is common to each positive output of 12 filament power supplies. To interrupt the arc discharging for the fault condition of the arc current unbalance, DCCT current monitor is placed at the positive output cable of the filament power supply. The plasma grid (G1) power supply has the maximum capability of 120 kV/70 A which consists of low voltage regulator with IGBT-switched chopper array system for the voltage control in unit of 600 V and the high voltage rectified transformers to supply DC voltage of 20 kV, 30 kV, and 50 kV. The output voltage of the G1 power supply is also connected to the input of the voltage divider system which supplies the gradient voltage to the gradient grid (G2) in the range of 80–90% of G1 voltage by changing tap of winding resistors in unit of 1%. The charged G1 voltage is turned on and off by the high voltage switch (HVS) system consisting of MOSFET fast semiconductor switches which can immediately be opened less than 1 μs when the ion source grid breakdown occurs. The decelerating grid (G3) power supply is inverter system using capacitor-charge power supply to supply maximum −5 kV/5 A. The important component in power supply system is the surge absorber near the ion source to limit the arc energy deposited to

Pharmaceutical supply chain models: A synthesis from a systems view of operations research

Directory of Open Access Journals (Sweden)

Ettore Settanni

Full Text Available This research evaluates reconfiguration opportunities in Pharmaceutical Supply Chains (PSC resulting from technology interventions in manufacturing, and new, more patient-centric delivery models. A critical synthesis of the academic and practice literature is used to identify, conceptualise, analyse and categorise PSC models. From a theoretical perspective, a systems view of operations research is adopted to provide insights on a broader range of OR activities, from conceptual to mathematical modelling and model solving, up to implementation.The research demonstrates that: 1 current definitions of the PSC are largely production-centric and fail to capture patient consumption, and hence healthcare outcomes; 2 most PSC mathematical models lack adequate conceptualisation of the structure and behaviour of the supply chain, and the boundary conditions that need to be considered for a given problem; 3 models do not adequately specify current unit operations or future production technology options, and are therefore unable to address the critical questions around alternative product or process technologies; 4 economic evaluations are limited to direct costing, rather than systemic approaches such as supply chain costing and total cost of ownership.While current models of the PSC may help with the optimisation of specific unit operations, their theoretical benefits could be offset by the dynamics of complex upstream (supply and downstream (distribution and healthcare delivery systems. To overcome these limitations, this research provides initial directions towards an integrated systems approach to PSC modelling. This perspective involves problem conceptualisation and boundary definition; design, formulation and solution of mathematical models, through to practical implementation of identified solutions. For both academics and practitioners, research findings suggest a systems approach to PSC modelling can provide improved conceptualisation and

Supply system with microprocessor control for electron gun

International Nuclear Information System (INIS)

Duplin, N.I.; Sergeev, N.N.

1988-01-01

Precision supply system for electron gun used in Auger-spectrometer is described. The supply system consists of control and high-voltage parts, made as separate units. Supply high-voltage unit includes system supply module, filament module to supply electron gun cathode and 6 high-volt modules to supply accelerating, modulating and three focusing electrodes of the gun. High-voltage modules have the following characteristics: U-(100-1000)V output voltage, 5x10 -5 U stability, 10 -5 xU pulsation amplitude, J-(0-5)A filament current change range at 10 -4 xJ stability. Control unit including microprocessor, timer and storage devices forms control voltage for all modules and regulates voltage and current of filament at electrodes

Qualitative Study to Explore Potential Directions for Improvements of Fruit and Vegetable Supply Chain Management: A Case Study of Malaysian Agrifood Corporation

OpenAIRE

Lukmanov, Arman

2010-01-01

The research was carried out to investigate the current supply chain management system of Malaysian Agrifood Corporation (MAFC) and recommend further potential directions of improvements of the supply chain management in terms of increasing its effectiveness and efficiency and keeping up with emerging trends and innovations which can be applied to the Malaysian food industry. MAFC is a Malaysian supply chain management company with integrated supply of fresh fruits and vegetables that are...

Smart Power Supply Systems for Mission Critical Facilities

Science.gov (United States)

Hirose, Keiichi; Babasaki, Tadatoshi

To develop the advanced and rich life, and the also economy and social activity continuously, various types of energy are necessary. At the same time, to protect the global environment and to prevent the depletion of natural resources, the effective and moreover efficient use of energy is becoming important. Electric power is one of the most important forms of energy for our life and society. This paper describes topics and survey results of technical trends regarding the electric power supply systems which are playing a core role as the important infrastructure to support the emergence of information-oriented society. Specifically, the power supply systems that enhance high power quality and reliability (PQR) are important for the steady growth of information and communication services. The direct current (DC) power, which has been used for telecommunications power systems and information and communications technologies (ICT), enables existing utilities' grid and distributed energy resources to keep a balance between supply and demand of small-scaled power systems or microgirds. These techniques are expected to be part of smartgrid technologies and facilitate the installation of distributed generators in mission critical facilities.

WORK SYSTEM ANALYSIS OF POWER SUPPLY IN OPTIMIZING ELECTRICITY ON PERSONAL COMPUTER (PC

Directory of Open Access Journals (Sweden)

Sudarmaji Sudarmaji

2017-12-01

Full Text Available Working Principles DC Power Supply - is an energy source for a computer to operate. The power supply changes the current from AC 110 volts to 60Hz or 220 volts 50Hz to DC + 3.3 volts, +5 volts and + 12 volts. Power Supply must carry a good and stable DC power supply so the system can run well. Tools running on the voltage supplied by the onboard voltage regulator, for example RIMM and RIMM require 2.5 volts while AGP AX and cards require 1.5 volts, both supplied by the onboard regulator of the motherboard. In addition to supplying power, the Power Supply can prevent the computer from starting until a Power Supply voltage exists at a predetermined area. Power Good is a sign of a special test that is sent to the motherboard as an active signal on the computer, usually marked by a green light when the power button is pressed. The current issued by the Power Supply is a direct current (DC, power output is composed of 200 watts, 250 watts, 300 watts, 350 watts, 400 watts to 600 watts. Computers with Intel Pentium 4 processors and above use power of 380 watts to 450 watts. Keywords: Power Supply, Computer, DC, Power Good, and volt

Accelerator-control-system interface for intelligent power supplies

International Nuclear Information System (INIS)

Cohen, S.

1992-01-01

A number of high-current high-precision magnet power supplies have been installed at the proton storage ring at the Los Alamos National Laboratory Accelerator Complex. The units replace existing supplies, powering large dipole magnets in the ring. These bending magnets require a high-current supply that is precise and stable. The control and interface design for these power supplies represents a departure from all others on-site. The supplies have sophisticated microprocessor control on-board and communicate with the accelerator control system via RS-422 (serial communications). The units, built by Alpha Scientific Electronics, Hayward, CA use a high-level ASCII control protocol. The low-level ''front-end'' software used by the accelerator control system has been written to accommodate these new devices. They communicate with the control system through a terminal server port connected to the site-wide ethernet backbone. Details of the software implementation for the analog and digital control of the supplies through the accelerator control system will be presented

Study of matrix converter as a current-controlled power supply in QUEST tokamak

International Nuclear Information System (INIS)

Liu, Xiaolong; Jiang, Yi; Nakamura, Kazuo

2011-01-01

Because QUEST tokamak has a divertor configuration with a higher κ and a negative n-index, a precise power supply with a rapid response is needed to control the vertical position of the plasma. A matrix converter is a direct power conversion device that uses an array of controlled bidirectional switches as the main power elements for creating a variable-output current system. This paper presents a novel three-phase to two-phase topological matrix converter as a proposed power supply that stabilizes the plasma vertical position and achieves unity input power factor. An indirect control strategy in which the matrix converter is split into a virtual rectifier stage and a virtual inverter stage is adopted. In the virtual rectifier stage, the instantaneous active power and reactive power are decoupled on the basis of system equations derived from the DQ transformation; hence, unity power factor is achieved. Space vector pulse width modulation is adopted to determine the switching time of each switch in the virtual rectifier; the output voltage of the virtual rectifier is adjusted by the virtual inverter stage to obtain the desired load current. Theoretical analyses and simulation results are provided to verify its feasibility. (author)

Study of pulse stretching in high current power supplies using multipulse techniques

International Nuclear Information System (INIS)

Trendler, R.C.

1977-01-01

Considerable interest exists at Fermilab to increase the pulse width of the Neutrino Focusing Horn to permit an increase in beam spill length from twenty (20) microseconds to one (1) millisecond. Two techniques to do this were examined: (1) a high current transformer, and (2) increased bank capacitance using the multi-power supply technique. The transformer is the most straightforward conceptually; it is, however, a complicated device requiring sizable changes to the existing horn power supply. This alternative is briefly reviewed. The second scheme involves pulsing a 20 kv 200 ka power supply to establish the required load current and then maintaining this current by the sequential pulsing of a number of low voltage high current power supplies. This alternative is discussed in detail with the results of tests performed on the Fermilab Focusing Horn System

Systemic-Functional Approach to Utilities Supplys

Directory of Open Access Journals (Sweden)

Nikolay I. Komkov

2017-01-01

Full Text Available Purpose: the purpose of the article consists in statement of management approach to development of utilities supply processes based on conflict situations decision – making search. It had appeared in the period of the transition from the planned and directive management to market development. Methods: the research methodology is based on the system analysis of full life cycle processes functioning, forecasting of complex systems development, mathematical modeling of processes of services supply and innovative and investment projects modeling as well as development of supplying services processes. Results: the results of the work are concentrated in the presentation of systemic-functional approach to managing the development of processes of municipal services, able to resolve conflict situations in this sphere. Conclusions and Relevance: the traditional management approach on the basis of elimination of "bottlenecks" and emergencies prevailing within planned and directive system at its transformation in the market conditions has led to accumulation of conflict situations and unsolvable problems. The offered systemic-functional approach based on forecasting of full life cycle of the modernized processes and the services providing systems allows to consider costs of modernization, prime cost and quality of the rendered services. 

Improvement of a high current DC power supply system for testing the large scaled superconducting cables and magnets

International Nuclear Information System (INIS)

Yamada, Shuichi; Chikaraishi, Hirotaka; Tanahashi, Shugo

1993-11-01

A dc 75 kA power supply system was constructed to test the superconducting (SC) R and D cables and magnets for the Large Helical Device. It consists of three 25 kA unit banks. A unit bank has two double-star-rectifier connections with the inter-phase reactors. A digital feedback control method is applied to the automatic current regulation (ACR) in each unit bank. For shortening the dead time of the feedback process, a new algorithm of a digital phase controller for the ACR is investigated. A Bode diagram of the feedback process is directly measured. It is confirmed that the dead time of the feedback process is reduced to one sixth, and that the feedback gain of PID compensation is improved by a factor of two from the original method. (author)

Nutrient supply, surface currents, and plankton dynamics predict zooplankton hotspots in coastal upwelling systems

Science.gov (United States)

Messié, Monique; Chavez, Francisco P.

2017-09-01

A simple combination of wind-driven nutrient upwelling, surface currents, and plankton growth/grazing equations generates zooplankton patchiness and hotspots in coastal upwelling regions. Starting with an initial input of nitrate from coastal upwelling, growth and grazing equations evolve phytoplankton and zooplankton over time and space following surface currents. The model simulates the transition from coastal (large phytoplankton, e.g., diatoms) to offshore (picophytoplankton and microzooplankton) communities, and in between generates a large zooplankton maximum. The method was applied to four major upwelling systems (California, Peru, Northwest Africa, and Benguela) using latitudinal estimates of wind-driven nitrate supply and satellite-based surface currents. The resulting zooplankton simulations are patchy in nature; areas of high concentrations coincide with previously documented copepod and krill hotspots. The exercise highlights the importance of the upwelling process and surface currents in shaping plankton communities.

Expansion of the high-voltage direct current transmission systems; Netzausbau mit Hochspannungs-Gleichstrom-Uebertragung

Energy Technology Data Exchange (ETDEWEB)

Spahic, Ervin; Benz, Thomas; Goerner, Raphael; Sass, Florian [ABB AG, Mannheim (Germany)

2012-12-15

In September 2010 the German federal government announced its energy concept for an environmentally friendly, reliable and affordable energy supply. This concept describes a ''path into the era of renewable energy'' up to the year 2050, with electricity production from photovoltaics and wind power taking centre stage. Since the expansion of renewable energy production is mainly taking place in the North (wind power) and the South (PV), this poses a great challenge to the electricity networks. It necessitates the expansion of power transmission systems, notably for transporting electricity generated by wind power in the North to the consumer centres in Western and Southern Germany. However, progress to this end has been very slow. For this reason a technical question now presents itself, namely whether high-voltage direct current technology could possibly offer a solution to the electricity transport problems associated with the energy turnaround.

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

International Nuclear Information System (INIS)

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

2006-01-01

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

Development of high-power inverter supply for current drive of FRC plasma

International Nuclear Information System (INIS)

Kitano, Katsuhisa; Higashikozono, Takamitsu; Okada, Shigefumi; Goto, Seiichi

2003-01-01

High-Power RF supply is developed for the current drive of FRC (Field Reversed Configuration) plasma. The rotating magnetic field is produced by the four antennas set in the parallel direction to the geometrical axis of the FRC and faced each other. The sinusoidal currents with shifted phases by 90 degree each other should be supplied to the antennas. The two power supplies are necessary if a pair of the antennas faced oppositely are connected. Considering the plasma parameters, the rotating field of 50-100kHz and 50G at the center axis is expected to be required. We develop the adequate RF power supply for the purpose. The power supply consists of the inverter circuit, the step-up transformer and the LC tank ciruit. For the switching device of the inverter circuit, the IGBT (Insulated Gate Bipolar Transistor) is adopted. The inverter circuit is full bridge type. To operate it at high voltages, its arm consists of the 3 IGBTs arranged series. The output of the inverter is connected to the tank circuit by way of the step-up transformer with air core. The tank circuit is the parallel circuit of the antenna and the capacitor. By the adjustment of the frequency of the inverter output to the resonance frequency of the tank circuit, the large sinusoidal waveform current is obtained. The developed power supply can produce the current of 5kA at 10kV to the dummy antenna with almost the same inductance of the antenna. (author)

Extending Perceived Supply Chain Boundaries to Motivate and Direct Change

DEFF Research Database (Denmark)

Englyst, Linda

2005-01-01

is argued to lead to different and predictable areas of attention and change. The paper is mainly conceptual, as it is discussed how perception and modeling of a supply chain induces pressures for different directions of change. Supply chain modeling is argued to be a tool to be used actively in change......Many a change effort has been initiated under the hat of supply chain management in the past decades, motivated by promises of improved performance based on network design and integration of business processes, information systems, and even organizations through the construction of various liaison...... structures. The present research is inspired by an industrial case study, which indicates that a widening of the supply chain perception along horizontal and vertical lines might serve as a point of entry for change. Extending the observed system in these dimensions and at different levels of detail...

Operations Management of Logistics and Supply Chain: Issues and Directions

OpenAIRE

Li, Xiang

2014-01-01

There has been consensus that logistics as well as supply chain management is a vital research field, yet with few literature reviews on this topic. This paper sets out to propose some hot issues in the current research, through a review of related literature from the perspective of operations management. In addition, we generate some insights and future research directions in this field.

Investigation of thermochemical biorefinery sizing and environmental sustainability impacts for conventional supply system and distributed preprocessing supply system designs

Energy Technology Data Exchange (ETDEWEB)

Muth, jr., David J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Langholtz, Matthew H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Tan, Eric [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jacobson, Jacob [Idaho National Lab. (INL), Idaho Falls, ID (United States); Schwab, Amy [National Renewable Energy Lab. (NREL), Golden, CO (United States); Wu, May [Argonne National Lab. (ANL), Argonne, IL (United States); Argo, Andrew [Sundrop Fuels, Golden, CO (United States); Brandt, Craig C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cafferty, Kara [Idaho National Lab. (INL), Idaho Falls, ID (United States); Chiu, Yi-Wen [Argonne National Lab. (ANL), Argonne, IL (United States); Dutta, Abhijit [National Renewable Energy Lab. (NREL), Golden, CO (United States); Eaton, Laurence M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Searcy, Erin [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2014-03-31

The 2011 US Billion-Ton Update estimates that by 2030 there will be enough agricultural and forest resources to sustainably provide at least one billion dry tons of biomass annually, enough to displace approximately 30% of the country's current petroleum consumption. A portion of these resources are inaccessible at current cost targets with conventional feedstock supply systems because of their remoteness or low yields. Reliable analyses and projections of US biofuels production depend on assumptions about the supply system and biorefinery capacity, which, in turn, depend upon economic value, feedstock logistics, and sustainability. A cross-functional team has examined combinations of advances in feedstock supply systems and biorefinery capacities with rigorous design information, improved crop yield and agronomic practices, and improved estimates of sustainable biomass availability. A previous report on biochemical refinery capacity noted that under advanced feedstock logistic supply systems that include depots and pre-processing operations there are cost advantages that support larger biorefineries up to 10 000 DMT/day facilities compared to the smaller 2000 DMT/day facilities. This report focuses on analyzing conventional versus advanced depot biomass supply systems for a thermochemical conversion and refinery sizing based on woody biomass. The results of this analysis demonstrate that the economies of scale enabled by advanced logistics offsets much of the added logistics costs from additional depot processing and transportation, resulting in a small overall increase to the minimum ethanol selling price compared to the conventional logistic supply system. While the overall costs do increase slightly for the advanced logistic supply systems, the ability to mitigate moisture and ash in the system will improve the storage and conversion processes. In addition, being able to draw on feedstocks from further distances will decrease the risk of biomass supply to

Characteristics of a direct methanol fuel cell system with the time shared fuel supplying approach

International Nuclear Information System (INIS)

Na, Youngseung; Kwon, Jungmin; Kim, Hyun; Cho, Hyejung; Song, Inseob

2013-01-01

DMFC (direct methanol fuel cell) systems usually employ two pumps for supplying the methanol solution. The conventional system configuration, however, may bring about free flow from the methanol reservoir and malfunctions in the self-priming of the pumps. When instruments such as check valves and pressure regulators are applied, they result in excessive weight and control system malfunctions. In this paper, a light and robust DMFC system is proposed. By using the time sharing approach to supply fuel with a 3-way valve, free flow does not occur because only one inlet is opened at one time which means that both the circulation flow from gas liquid separator and the fuel flow from the methanol cartridge are not allowed to be opened at same time. As a result, back flow and self-priming problems do not occur. This makes the system stable and robust due to the removal of both the check valves and the fluctuation from unstable back pressure. Stabilized system doesn't need excessive battery buffering and recycling water any more, which are responsible for the heavy system. The proposed system performs the same level of power and efficiency with the conventional system. Adaptability is also carried out in various environmental temperature conditions. - Highlights: ►A light and robust DMFC system is proposed. ► The circulation pump is able to self-prime by itself after long term storage. ► The time sharing approach to supply fuel enables to control the methanol concentration precisely. ► The methanol concentration is controlled without free flow and the back flow from the fuel feeding pump. ► The excessive buffer of the batteries and the recycling water level are reduced

Operations Management of Logistics and Supply Chain: Issues and Directions

Directory of Open Access Journals (Sweden)

Xiang Li

2014-01-01

Full Text Available There has been consensus that logistics as well as supply chain management is a vital research field, yet with few literature reviews on this topic. This paper sets out to propose some hot issues in the current research, through a review of related literature from the perspective of operations management. In addition, we generate some insights and future research directions in this field.

The clinical endocrinology workforce: current status and future projections of supply and demand.

Science.gov (United States)

Vigersky, Robert A; Fish, Lisa; Hogan, Paul; Stewart, Andrew; Kutler, Stephanie; Ladenson, Paul W; McDermott, Michael; Hupart, Kenneth H

2014-09-01

Many changes in health care delivery, health legislation, and the physician workforce that affect the supply and demand for endocrinology services have occurred since the first published workforce study of adult endocrinologists in 2003. The objective of the study was to assess the current adult endocrinology workforce data and provide the first analysis of the pediatric endocrinology workforce and to project the supply of and demand for endocrinologists through 2025. A workforce model was developed from an analysis of proprietary and publicly available databases, consultation with a technical expert panel, and the results of an online survey of board-certified endocrinologists. The Endocrine Society commissioned The Lewin Group to estimate current supply and to project gaps between supply and demand for endocrinologists. A technical expert panel of senior endocrinologists provided context, clinical information, and direction. The following were measured: 1) the current adult and pediatric endocrinology workforce and the supply of and demand for endocrinologists through 2025 and 2) the number of additional entrants into the endocrinology work pool that would be required to close the gap between supply and demand. Currently there is a shortage of approximately 1500 adult and 100 pediatric full-time equivalent endocrinologists. The gap for adult endocrinologists will expand to 2700 without an increase in the number of fellows trained. An increase in the prevalence of diabetes mellitus further expands the demand for adult endocrinologists. The gap can be closed in 5 and 10 years by increasing the number of fellowship positions by 14.4% and 5.5% per year, respectively. The gap between supply and demand for pediatric endocrinologists will close by 2016, and thereafter an excess supply over demand will develop at the current rate of new entrants into the work force. There are insufficient adult endocrinologists to satisfy current and future demand. A number of proactive

Evaluation of “direct input” effectiveness for industrial enterprises power supply

Directory of Open Access Journals (Sweden)

Malinina Tatyana

2017-01-01

Full Text Available The cost of energy has increased significantly for the industrial enterprises over the recent years, due to an increase in the electricity tariffs and the changes in the rules of the electricity market. Tariffs for electricity sold to consumers, differentiated according to various parameters, one of which is the voltage range. The higher the voltage range, the lower the tariffs, and thus, the consumer pays less for the supplied energy. Currently only for big consumers made energy supply “direct input” through the construction of an overhead line (OL with a nominal voltage of 110 kV or 220 kV. However, it is advisable to consider the issue of power supply efficiency of big and medium-sized industrial enterprises based on the “direct input”. The questions of voltage level study based on empirical formulas are considered in the article, expressing the dependence of the voltage from the transmission distance and the amount of transmitted power. It was proven that these formulas give a large spread, so intermediate voltage classes 35 kV and 110 kV, which compared with the traditional option of power supply on the basis of the cable line 10 kV, have been selected. Based on the technical and economic calculations it has been proved the value of the transmit power and length of the line at which the power supply of industrial enterprise on the basis of “ direct input” with a nominal voltage of 110 kV becomes effective.

Investigation of thermochemical biorefinery sizing and environmental sustainability impacts for conventional supply system and distributed pre-processing supply system designs

Energy Technology Data Exchange (ETDEWEB)

David J. Muth, Jr.; Matthew H. Langholtz; Eric C. D. Tan; Jacob J. Jacobson; Amy Schwab; May M. Wu; Andrew Argo; Craig C. Brandt; Kara G. Cafferty; Yi-Wen Chiu; Abhijit Dutta; Laurence M. Eaton; Erin M. Searcy

2014-08-01

The 2011 US Billion-Ton Update estimates that by 2030 there will be enough agricultural and forest resources to sustainably provide at least one billion dry tons of biomass annually, enough to displace approximately 30% of the country's current petroleum consumption. A portion of these resources are inaccessible at current cost targets with conventional feedstock supply systems because of their remoteness or low yields. Reliable analyses and projections of US biofuels production depend on assumptions about the supply system and biorefinery capacity, which, in turn, depend upon economic value, feedstock logistics, and sustainability. A cross-functional team has examined combinations of advances in feedstock supply systems and biorefinery capacities with rigorous design information, improved crop yield and agronomic practices, and improved estimates of sustainable biomass availability. A previous report on biochemical refinery capacity noted that under advanced feedstock logistic supply systems that include depots and pre-processing operations there are cost advantages that support larger biorefineries up to 10 000 DMT/day facilities compared to the smaller 2000 DMT/day facilities. This report focuses on analyzing conventional versus advanced depot biomass supply systems for a thermochemical conversion and refinery sizing based on woody biomass. The results of this analysis demonstrate that the economies of scale enabled by advanced logistics offsets much of the added logistics costs from additional depot processing and transportation, resulting in a small overall increase to the minimum ethanol selling price compared to the conventional logistic supply system. While the overall costs do increase slightly for the advanced logistic supply systems, the ability to mitigate moisture and ash in the system will improve the storage and conversion processes. In addition, being able to draw on feedstocks from further distances will decrease the risk of biomass supply to

ISABELLE magnet power supply system performance analysis

International Nuclear Information System (INIS)

Edwards, R.J.

1981-01-01

The power supply system that will energize the superconducting magnets in the ISABELLE 400 x 400 GeV accelerator must supply various voltages and currents. The voltages for the correction winding range from ten to one hundred twenty-five volts unipolar and bipolar with current rating of 50 to 300 amperes. The main field winding requires voltages from 90V (at flattop) to 600V during maximum ramp rate or acceleration cycle. The power supplies are programmable over their full range of output current with a reproducibility error varying from +- 10 ppM to +- 400 ppM of full scale. Included within the reproducibility error are the long and short term stability requirements of the power supplies. The purpose of this paper is to define some of the design goals and outline the approach taken in reaching these goals

Performance evaluation of directly photovoltaic powered DC PM (direct current permanent magnet) motor – propeller thrust system

International Nuclear Information System (INIS)

Atlam, Ozcan; Kolhe, Mohan

2013-01-01

Photovoltaic (PV) powered directly coupled electro-mechanical system has wide applications (e.g. PV powered cooling fans in green houses, PV water pumping system, solar vehicles). The objective of this work is to analyse the operation of directly PV powered DC PM (direct current permanent magnet) motor – propeller system for selection of motor parameters. The performance of such system mainly depends on the incident solar radiation, operating cell temperature, DC motor and propeller load parameters. It is observed that the operating points of the PV DC PM motor – propeller system matches very closely with the maximum power points (MPPs) of the PV array, if the DC PM motor – propeller parameters have been properly selected. It is found that for a specific application of such type of system, matching of torque–speed operating points with respect to the maximum power points of PV array are very important. It is ascertained through results that the DC PM motor's armature resistance, magnetic field constant, starting current to overcome the starting torque and torque coefficient are the main parameters. In designing a PV powered DC PM motor for a specific application, selection of these parameters are important for maximum utilization of the PV array output. The results of this system are useful for designing of directly PV powered DC PM motor's for aerodynamic applications. - Highlights: • We analyse the performance of directly PV powered DC PM motor – propeller system. • We examine PV electro-mechanical system for selection of DC motor parameters. • Matching of torque–speed curve to maximum power points of PV array is important

An image-guided transcranial direct current stimulation system: a pilot phantom study

International Nuclear Information System (INIS)

Jung, Young-Jin; Kim, Jung-Hoon; Kim, Daejeong; Im, Chang-Hwan

2013-01-01

In this study, an image-guided transcranial direct current stimulation (IG-tDCS) system that can deliver an increased stimulation current to a target brain area without the need to adjust the location of an active electrode was implemented. This IG-tDCS system was based on the array-type tDCS concept, which was validated through computer simulations in a previous study. Unlike a previous study, the present IG-tDCS system adopts a single reference electrode and an active electrode array consisting of 16 (4 × 4) sub-electrodes. The proposed IG-tDCS system is capable of shaping current flow inside the human head by controlling the input currents of the arrayed electrodes. Once a target brain area has been selected, the optimal injection current of each arrayed sub-electrode is evaluated automatically using a genetic algorithm in order to deliver the maximum available current to the target area. The operation of our pilot system was confirmed through a simple phantom experiment. (paper)

Protection and switching system for the RFX power supply

International Nuclear Information System (INIS)

Browning, J.L.; Gray, J.W.; Mace, T.A.; Varley, G.L.

1986-01-01

The RFX toroidal field power supply comprises a large 4.8MJ (max) modular capacitor bank and four 14MW AC/DC converter flat-top power supply modules. The high fault level associated with the capacitor banks presents a problem in the design of the switching system, since mistiming could produce large currents in the flat-top supplies. The poloidal circuit consists of four groups of magnetising windings connected in series, each with its own flat-top convertor supply and opening switch transfer system. The flat-top converter supplies are needed when the transfer voltage has fallen from approximately 40kV to 1kV. Solutions to the problem of designing a fault-tolerant system which presents no danger to the flat-top converters are described in the paper. The adopted methods make use of hybrid ignitron/mechanical switches to give the required combination of switching speed and current carrying capacity, together with careful attention to the circuit layout of different switching elements. (author)

Object Detection: Current and Future Directions

Directory of Open Access Journals (Sweden)

Rodrigo eVerschae

2015-11-01

Full Text Available Object detection is a key ability required by most computer and robot vision systems. The latest research on this area has been making great progress in many directions. In the current manuscript we give an overview of past research on object detection, outline the current main research directions, and discuss open problems and possible future directions.

United States enrichment supply - policy and direction

International Nuclear Information System (INIS)

Voigt, W.R. Jr.; Peske, S.E.

1982-01-01

Recognizing our position as the leader in commercial enrichment services, DOE has established a flexible approach to meeting changing market realities and customer needs. The major elements of this strategy are aggressive deployment of advanced technologies, more flexible contract terms and conditions, and near-term production optimization, all of which are based on a supply strategy which carefully balances near-term requirements with long-range responsibilities. The current surplus of separative work in the world market may afford some near-term opportunities for economy. However, a secure nuclear energy system must be based on assured long-term supply availability at reasonable prices. By utilizing the flexibilities of our large production base and maintaining our demonstrated technological advantages, DOE is confident that the US will continue to be a vital and major competitor in the international nuclear fuel market. 4 figures

Design of constant current charging power supply for J-TEXT ohmic field capacitor banks

International Nuclear Information System (INIS)

Lv Shudong; Zhang Ming; Rao Bo; Yu Kexun; Yang Cheng

2014-01-01

The charging characteristic of the capacitor charging power supply was analyzed with practical series resonant topology. The method that setting two current taps and regulating PWM switching frequency was putted forward with close loop controlling algorithm to charge the multi-group capacitor banks with constant current. A capacitor charging power supply with the max output current 6.5 A and the max output voltage 2000 V is designed. Experimental results show that, this power supply can charge the four capacitor banks to any four different voltages in 1 minute with charging accuracy less than 1%, and meet the requirements of J-TEXT ohmic field power system. (authors)

Fault Analysis of ITER Coil Power Supply System

International Nuclear Information System (INIS)

Song, In Ho; Jun, Tao; Benfatto, Ivone

2009-01-01

The ITER magnet coils are all designed using superconductors with high current carrying capability. The Toroidal Field (TF) coils operate in a steadystate mode with a current of 68 kA and discharge the stored energy in case of quench with using 9 interleaved Fast Discharge Units (FDUs). The Central Solenoid (CS) coils and Poloidal Field (PF) coils operate in a pulse mode with currents of up to 45 kA and require fast variation of currents inducing more than 10 kV during normal operation on the coil terminals using Switching Network (SN) systems (CSs, PF1 and 6) and Booster and VS converters (PF2 to 5), which are series connected to Main converters. SN and FDU systems comprise high current DC circuit breakers and resistors for generating high voltage (SN) and to dissipate magnetic energy (FDUs). High transient voltages can arise due to the switching operation of SN and FD and the characteristics of resistors and stray components of DC distribution systems. Also, faults in power supply control such as shorts or grounding faults can produce higher voltages between terminals and between terminal and ground. Therefore, the design of the coil insulation, coil terminal regions, feeders, feed throughs, pipe breaks and instrumentation must take account of these high voltages during normal and abnormal conditions. Voltage insulation level can be defined and it is necessary to test the coils at higher voltages, to be sure of reliable performance during the lifetime of operation. This paper describes the fault analysis of the TF, CS and PF coil power supply systems, taking account of the stray parameter of the power supply and switching systems and inductively coupled superconducting coil models. Resistor grounding systems are included in the simulation model and all fault conditions such as converter hardware and software faults, switching system hardware and software faults, DC short circuits and single grounding faults are simulated. The occurrence of two successive faults

Supply-demand balance in outward-directed networks and Kleiber's law

OpenAIRE

Painter Page R

2005-01-01

Abstract Background Recent theories have attempted to derive the value of the exponent α in the allometric formula for scaling of basal metabolic rate from the properties of distribution network models for arteries and capillaries. It has recently been stated that a basic theorem relating the sum of nutrient currents to the specific nutrient uptake rate, together with a relationship claimed to be required in order to match nutrient supply to nutrient demand in 3-dimensional outward-directed n...

Passive AC network supplying the integration of CCC-HVDC and VSC-HVDC systems

OpenAIRE

BIDADFAR, Ali; ABEDI, Mehrdad; KARRARI, Mehdi

2014-01-01

The integration of a capacitor-commutated converter (CCC) high-voltage direct current (HVDC) (CCC-HVDC) and voltage source converter (VSC) HVDC (VSC-HVDC) is proposed in this paper to supply entirely passive AC networks. The key point of this integration is the flat characteristic of the DC voltage of the CCC-HVDC, which provides the condition for the VSC to connect to the CCC DC link via a current regulator. The advantages of the proposed combined infeeding system are the requirement o...

Turn-key supply for the power supplies of the control coils of wendelstein 7-X experiment

International Nuclear Information System (INIS)

Jauregi, E.; Ganuza, D.; Garcia, I.; Rio, J.M. del; Rummel, T.; Fuellenbach, F.

2003-01-01

In the Max-Planck Institute for Plasma Physics, IPP, in Greifswald, a new stellerator is being built for fusion research experiments, the so called Wendelstein 7-X Experiment. JEMA Company has designed, manufacture and supply the turnkey system which energises the ten control coils in the stellerator. The system comprises ten independent Switch-mode power supplies, and the central distribution stations for power, cooling and control facilities. Each power supply must provide a controlled current compounded of direct current and 0-20 Hz bandwidth ac current in a range of almost 3 kA at low voltage, 30 V, in four quadrants. Positive and negative voltage and sinusoidal current with low harmonic distortion is required by load. The selected design is based on Switch-mode-power supply technology (SMPS) providing the system with a very high regulation response (very low current and voltage ripple) and excellent input power factor, keeping the grid total harmonic distortion (THD) under minimum values. The sources can be operated locally as independent systems or they can be co-ordinated from a main control keeping current synchronisation requirements. The system in its entirety requires a high efficiency due to thermal considerations and reduced space. The system presented here introduces a decisive solution for the future power supplies to superconducting or regular coils, where the regulation, precision and ripple are the basic requirements for the design. During year 2000 the design stage was covered and in 2001 a first prototype for the power supplies was manufactured and successfully tested at factory. The entire system has been installed over this year after the series fabrication and it is currently working at IPP facilities, waiting for the acceptance tests scheduled before end of the year. This paper aims to explain the different stages the company went through in order to get validation of the power supply system and make it running at its last location

Simulation evaluation of capacitor bank impact on increasing supply current for alumunium production

Science.gov (United States)

Hasan, S.; Badra, K.; Dinzi, R.; Suherman

2018-03-01

DC current supply to power the electrolysis process in producing aluminium at PT Indonesia Asahan Aluminium (Persero) is about 193 kA. At this condition, the load voltage regulator (LVR) transformer generates 0.89 lagging power factor. By adding the capacitor bank to reduce the harmonic distortion, it is expected that the supply current will increase. This paper evaluates capacitor bank installation impact on the system by using ETAP 12.0 simulation. It has been obtained that by installing 90 MVAR capacitor bank in the secondary part of LVR, the power factor is corrected about 8% and DC current increases about 13.5%.

Adjustable direct current and pulsed circuit fault current limiter

Science.gov (United States)

Boenig, Heinrich J.; Schillig, Josef B.

2003-09-23

A fault current limiting system for direct current circuits and for pulsed power circuit. In the circuits, a current source biases a diode that is in series with the circuits' transmission line. If fault current in a circuit exceeds current from the current source biasing the diode open, the diode will cease conducting and route the fault current through the current source and an inductor. This limits the rate of rise and the peak value of the fault current.

Method and system for a gas tube-based current source high voltage direct current transmission system

Science.gov (United States)

She, Xu; Chokhawala, Rahul Shantilal; Bray, James William; Sommerer, Timothy John; Zhou, Rui; Zhang, Di

2017-08-29

A high-voltage direct-current (HVDC) transmission system includes an alternating current (AC) electrical source and a power converter channel that includes an AC-DC converter electrically coupled to the electrical source and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and the DC-AC inverter each include a plurality of legs that includes at least one switching device. The power converter channel further includes a commutating circuit communicatively coupled to one or more switching devices. The commutating circuit is configured to "switch on" one of the switching devices during a first portion of a cycle of the H-bridge switching circuits and "switch off" the switching device during a second portion of the cycle of the first and second H-bridge switching circuits.

ELECTROMECHANICAL TRANSIENT PROCESSES DURING SUPPLY VOLTAGE CHANGING IN THE SYSTEM OF POLYMER INSULATION COVERING OF THE CURRENT-CARRYING CORE OF ULTRA HIGH VOLTAGE CABLES

Directory of Open Access Journals (Sweden)

V. M. Zolotaryov

2018-04-01

Full Text Available Aim. The article is devoted to the analysis of the electromechanical transient processes in a system of three frequency-controlled electric drives based on asynchronous motors that control current-carrying core motion, as well as to the study of the effect of such processes on the modes applying three-layer polymer insulation to the current-carrying core. Technique. The study was conducted based on the concepts of electromechanics, electromagnetic field theory, mathematical physics, mathematical modeling. Results. A mathematical model has been developed to analyze transients in an electromechanical system consisting of three frequency-controlled electric drives providing current-carrying core motion of ultra-high voltage cables in an inclined extrusion line. The coordination of the electromechanical parameters of the system drives has been carried out and the permissible changes in the supply voltage at the limiting mass while moving current-carrying core of ultra-high voltage cables with applied polymer insulation have been estimated. Scientific novelty. For the first time it is determined that with the limiting mass of the current-carrying core, the electromechanical system allows to stabilize the current-carrying core speed with the required accuracy at short-term decreases in the supply voltage by no more than 27 % of its amplitude value. It is also shown that this system is resistant to short-term increases in voltage by 32 % for 0.2 s. Practical significance. Using the developed model, it is possible to calculate the change in the configuration and speed of the slack current-carrying core when applying polymer insulation, depending on the specific mass of the current-carrying core per unit length, its tension at the bottom, the torque of the traction motor and the supply voltage to achieve stable operation of the system and accurate working of the set parameters.

High-current power supply for accelerator magnets

International Nuclear Information System (INIS)

Bourkland, K.R.; Winje, R.A.

1978-01-01

A power supply for controlling the current to accelerator magnets produces a high current at a precisely controlled time rate of change by varying the resonant frequency of an RLC circuit that includes the magnet and applying the current to the magnet during a predetermined portion of the waveform of an oscillation. The current is kept from going negative despite the reverse-current characteristics of thyristors by a quenching circuit

Direct current hopping conductance in one-dimensional diagonal disordered systems

Institute of Scientific and Technical Information of China (English)

Ma Song-Shan; Xu Hui; Liu Xiao-Liang; Xiao Jian-Rong

2006-01-01

Based on a tight-binding disordered model describing a single electron band, we establish a direct current (dc) electronic hopping transport conductance model of one-dimensional diagonal disordered systems, and also derive a dc conductance formula. By calculating the dc conductivity, the relationships between electric field and conductivity and between temperature and conductivity are analysed, and the role played by the degree of disorder in electronic transport is studied. The results indicate the conductivity of systems decreasing with the increase of the degree of disorder, characteristics of negative differential dependence of resistance on temperature at low temperatures in diagonal disordered systems, and the conductivity of systems decreasing with the increase of electric field, featuring the non-Ohm's law conductivity.

Environmental inventories for future electricity supply systems for Switzerland

Energy Technology Data Exchange (ETDEWEB)

Dones, R; Gantner, U; Hirschberg, S [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Doka, G; Knoepfel, I [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

1996-02-01

This report provides the analysis of environmental inventories for selected electricity supply systems considered as possible options to meet the expected electricity demand in Switzerland in year 2030. Two possible electricity demand level cases were postulated by VSE, both under the basic assumption of economic growth: a high-growth demand case corresponding to a yearly increase of 2% from year 1995 to year 2010 and 1% from year 2010 to year 2030, and a low-growth demand case corresponding to a yearly increase of 1% from year 1995 to year 2010 and 0.5% from year 2010 to year 2030. The base (i.e. secured) supply in year 2030 will be, according to VSE, totally dominated by hydro with rather minor contributions from combined heat-and-power plants, small gas turbines, incinerators and solar photovoltaic plants. Due to decommissioning of the currently operating nuclear power plants and expiration of long-term electricity import contracts there will eventually occur a gap between the postulated electricity demand and the base supply. VSE provided seven options to cover this gap, defined in terms of mixes with different contributions from gas, coal, nuclear and solar chains; in this context a distinction is also made with respect to shares of domestic and imported electricity. The systems considered represent advanced technologies, regarded as either typical or most suitable for the Swiss conditions. System-specific input to the present analysis has been partially generated based on direct contacts with the industry. Life Cycle Analysis (LCA) was used to establish environmental inventories for the systems analysed. The analysis has been performed on three levels:(1) individually for each system considered, (2) comparison of systems, (3) comparison of supply options. Results are also provided for these three levels.

Proposed high voltage power supply for the ITER relevant lower hybrid current drive system

International Nuclear Information System (INIS)

Sharma, P.K.; Kazarian, F.; Garibaldi, P.; Gassman, T.; Artaud, J.F.; Bae, Y.S.; Belo, J.; Berger-By, G.; Bernard, J.M.; Cara, Ph.; Cardinali, A.; Castaldo, C.; Ceccuzzi, S.; Cesario, R.; Decker, J.; Delpech, L.; Ekedahl, A.; Garcia, J.; Goniche, M.; Guilhem, D.

2011-01-01

In the framework of the EFDA task HCD-08-03-01, the ITER lower hybrid current drive (LHCD) system design has been reviewed. The system aims to generate 24 MW of RF power at 5 GHz, of which 20 MW would be coupled to the plasmas. The present state of the art does not allow envisaging a unitary output of the klystrons exceeding 500 kW, so the project is based on 48 klystron units, leaving some margin when the transmission lines losses are taken into account. A high voltage power supply (HVPS), required to operate the klystrons, is proposed. A single HVPS would be used to feed and operate four klystrons in parallel configuration. Based on the above considerations, it is proposed to design and develop twelve HVPS, based on pulse step modulator (PSM) technology, each rated for 90 kV/90 A. This paper describes in details, the typical electrical requirements and the conceptual design of the proposed HVPS for the ITER LHCD system.

Surface EEG-Transcranial Direct Current Stimulation (tDCS) Closed-Loop System.

Science.gov (United States)

Leite, Jorge; Morales-Quezada, Leon; Carvalho, Sandra; Thibaut, Aurore; Doruk, Deniz; Chen, Chiun-Fan; Schachter, Steven C; Rotenberg, Alexander; Fregni, Felipe

2017-09-01

Conventional transcranial direct current stimulation (tDCS) protocols rely on applying electrical current at a fixed intensity and duration without using surrogate markers to direct the interventions. This has led to some mixed results; especially because tDCS induced effects may vary depending on the ongoing level of brain activity. Therefore, the objective of this preliminary study was to assess the feasibility of an EEG-triggered tDCS system based on EEG online analysis of its frequency bands. Six healthy volunteers were randomized to participate in a double-blind sham-controlled crossover design to receive a single session of 10[Formula: see text]min 2[Formula: see text]mA cathodal and sham tDCS. tDCS trigger controller was based upon an algorithm designed to detect an increase in the relative beta power of more than 200%, accompanied by a decrease of 50% or more in the relative alpha power, based on baseline EEG recordings. EEG-tDCS closed-loop-system was able to detect the predefined EEG magnitude deviation and successfully triggered the stimulation in all participants. This preliminary study represents a proof-of-concept for the development of an EEG-tDCS closed-loop system in humans. We discuss and review here different methods of closed loop system that can be considered and potential clinical applications of such system.

OVERVIEW OF THE RHIC INSERTION REGION, SEXTUPOLE, AND SNAKE POWER SUPPLY SYSTEMS

International Nuclear Information System (INIS)

BRUNO, D.; ENG, W.; GANETIS, G.; LAMBIASE, R.F.; SANDBERG, J.

2001-01-01

The Relativistic Heavy Ion Collider (RHIC) was commissioned in 1999 and 2000. RHIC requires power supplies to supply currents to highly inductive superconducting magnets. The RHIC Insertion Region (IR) contains many shunt power supplies to trim the current of different magnet elements in a large superconducting magnet circuit. There are a total of 237 Insertion Region power supplies in both RHIC rings. RHIC also requires sextupole power supplies. One sextupole power supply is connected across 12 sextupole magnets. There are a total of 24 sextupole power supplies in both rings. Snake magnets are also a part of the RHIC ring, and these snake magnets also require power supplies. There shall be a total of 24 snake power supplies in both rings. Power supply technology, connections, control systems and interfacing with the Quench Protection System will be presented

Installation and operation of the Plantwide Fire Protection Systems and related Domestic Water Supply Systems

International Nuclear Information System (INIS)

1991-12-01

A safe work environment is needed to support the Savannah River Site (SRS) mission of producing special nuclear material. This Environmental Assessment (EA) assesses the potential environmental impact(s) of adding to and upgrading the Plantwide Fire Protection System and selected related portions of the Domestic Water Supply System at SRS, Aiken, South Carolina. The following objectives are expected to be met by this action: Prevent undue threat to public health and welfare from fire at SRS; prevent undue hazard to employees at SRS from fire; prevent unacceptable delay to vital DOE programs as a result of fire at SRS; keep fire related property damage at SRS to a manageable level;, and provide an upgraded supply of domestic water for the Reactor Areas. The Reactor Areas' domestic water supplies do not meet current demand capacity due to the age and condition of the 30-year old iron piping. In addition, the water quality for these supplies is not consistent with current SCDHEC requirements. Therefore, DOE proposes to upgrade this Domestic Water Supply System to meet current demand and quality levels, as well as the needs of fire protection system improvement

Upgrade of DC power supply system in ITER CS model coil test facility

International Nuclear Information System (INIS)

Shimono, Mitsugu; Uno, Yasuhiro; Yamazaki, Keita; Kawano, Katsumi; Isono, Takaaki

2014-03-01

Objective of the ITER CS Model Coil Test Facility is to evaluate a large scale superconducting conductor for fusion using the Central Solenoid (CS) Model Coil, which can generate a 13T magnetic field in the inner bore with a 1.5 m diameter. The facility is composed of a helium refrigerator / liquefier system, a DC power supply system, a vacuum system and a data acquisition system. The DC power supply system supplies currents to two superconducting coils, the CS Model Coil and an insert coil. A 50-kA DC power supply is installed for the CS Model Coil and two 30 kA DC power supplies are installed for an insert coil. In order to evaluate superconducting performance of a conductor used for ITER Toroidal Field (TF) coils whose operating current is 68 kA, the line for an insert coil is upgraded. A 10 kA DC power supply was added, DC circuit breakers were upgraded, bus bars and current measuring instrument were replaced. In accordance to the upgrade, operation manual was revised. (author)

The NASA Human Space Flight Supply Chain, Current and Future

Science.gov (United States)

Zapata, Edgar

2007-01-01

The current NASA Human Space Flight transportation system, the Space Shuttle, is scheduled for final flight in 2010. The Exploration initiative will create a new capability with a combination of existing systems and new flight and ground elements. To fully understand and act on the implications of such change it is necessary to understand what, how, when and where such changes occur and more importantly, how all these interact. This paper presents Human Space Flight, with an emphasis on KSC Launch and Landing, as a Supply Chain of both information and materials. A supply chain methodology for understanding the flow of information and materials is presented. Further, modeling and simulation projects funded by the Exploration initiative to understand the NASA Exploration Supply Chain are explained. Key concepts and their purpose, including the Enterprise, Locations, Physical and Organizational Functional Units, Products, and Resources, are explained. It is shown that the art, science and perspective of Supply Chain Management is not only applicable to such a government & contractor operation, it is also an invaluable approach for understanding, focusing improvement and growth. It is shown that such commercial practice applies to Human Space Flight and is invaluable towards one day creating routine, affordable access to and from space.

Power supply system for negative ion source at IPR

Science.gov (United States)

Gahlaut, Agrajit; Sonara, Jashwant; Parmar, K. G.; Soni, Jignesh; Bandyopadhyay, M.; Singh, Mahendrajit; Bansal, Gourab; Pandya, Kaushal; Chakraborty, Arun

2010-02-01

The first step in the Indian program on negative ion beams is the setting up of Negative ion Experimental Assembly - RF based, where 100 kW of RF power shall be coupled to a plasma source producing plasma of density ~5 × 1012 cm-3, from which ~ 10 A of negative ion beam shall be produced and accelerated to 35 kV, through an electrostatic ion accelerator. The experimental system is modelled similar to the RF based negative ion source, BATMAN presently operating at IPP, Garching, Germany. The mechanical system for Negative Ion Source Assembly is close to the IPP source, remaining systems are designed and procured principally from indigenous sources, keeping the IPP configuration as a base line. High voltage (HV) and low voltage (LV) power supplies are two key constituents of the experimental setup. The HV power supplies for extraction and acceleration are rated for high voltage (~15 to 35kV), and high current (~ 15 to 35A). Other attributes are, fast rate of voltage rise (< 5ms), good regulation (< ±1%), low ripple (< ±2%), isolation (~50kV), low energy content (< 10J) and fast cut-off (< 100μs). The low voltage (LV) supplies required for biasing and providing heating power to the Cesium oven and the plasma grids; have attributes of low ripple, high stability, fast and precise regulation, programmability and remote operation. These power supplies are also equipped with over-voltage, over-current and current limit (CC Mode) protections. Fault diagnostics, to distinguish abnormal rise in currents (breakdown faults) with over-currents is enabled using fast response breakdown and over-current protection scheme. To restrict the fault energy deposited on the ion source, specially designed snubbers are implemented in each (extraction and acceleration) high voltage path to swap the surge energy. Moreover, the monitoring status and control signals from these power supplies are required to be electrically (~ 50kV) isolated from the system. The paper shall present the

Power supply system for negative ion source at IPR

International Nuclear Information System (INIS)

Gahlaut, Agrajit; Sonara, Jashwant; Parmar, K G; Soni, Jignesh; Bandyopadhyay, M; Singh, Mahendrajit; Bansal, Gourab; Pandya, Kaushal; Chakraborty, Arun

2010-01-01

The first step in the Indian program on negative ion beams is the setting up of Negative ion Experimental Assembly - RF based, where 100 kW of RF power shall be coupled to a plasma source producing plasma of density ∼5 x 10 12 cm -3 , from which ∼ 10 A of negative ion beam shall be produced and accelerated to 35 kV, through an electrostatic ion accelerator. The experimental system is modelled similar to the RF based negative ion source, BATMAN presently operating at IPP, Garching, Germany. The mechanical system for Negative Ion Source Assembly is close to the IPP source, remaining systems are designed and procured principally from indigenous sources, keeping the IPP configuration as a base line. High voltage (HV) and low voltage (LV) power supplies are two key constituents of the experimental setup. The HV power supplies for extraction and acceleration are rated for high voltage (∼15 to 35kV), and high current (∼ 15 to 35A). Other attributes are, fast rate of voltage rise (< 5ms), good regulation (< ±1%), low ripple (< ±2%), isolation (∼50kV), low energy content (< 10J) and fast cut-off (< 100μs). The low voltage (LV) supplies required for biasing and providing heating power to the Cesium oven and the plasma grids; have attributes of low ripple, high stability, fast and precise regulation, programmability and remote operation. These power supplies are also equipped with over-voltage, over-current and current limit (CC Mode) protections. Fault diagnostics, to distinguish abnormal rise in currents (breakdown faults) with over-currents is enabled using fast response breakdown and over-current protection scheme. To restrict the fault energy deposited on the ion source, specially designed snubbers are implemented in each (extraction and acceleration) high voltage path to swap the surge energy. Moreover, the monitoring status and control signals from these power supplies are required to be electrically (∼ 50kV) isolated from the system. The paper shall

Design considerations for high current regulated DC power supplies with reference to 600 kW variable DC power supply

International Nuclear Information System (INIS)

Ushakumari; Garud, A.N.; Nadkarni, S.S.

1980-01-01

High current regulated dc power supplies find increasing applications in industry and research. The power rating of these supplies vary from few killowatts to megawatts. The general requirements of these supplies for various applications and the techniques used to achieve the desired performance are presented. The design and selection of various circuit blocks namely the rectifier transformer, multiphase rectifier arrangement, SCR paralleling and current sensing techniques, are discussed in detail for a 600 killowatt current controlled supply developed in the Bhabha Atomic Research Centre, Bombay, and used for the thermal studies of reactor components. The power supply incorporates paralleled phase controlled thyristors with a closed loop feedback circuitary to achieve a current stability of 0.1% and smooth output variation from 10 to 100%. (auth.)

DAΦNE magnet power supply system

International Nuclear Information System (INIS)

Ricci, R.; Sanelli, C.; Stecchi, A.

1998-01-01

The e + -e - , 1020 MeV at center of mass, Particle Accelerator Complex DAΦNE, consists of a linear accelerator (Linac), a damping ring (D.A.), nearly 180 m of transfer lines (T.L.) and two storage rings (S.R.), that intersect each other in two points (I.P.), for Φ particle production. The D.A., T.L. and S.R. magnets are powered by means of 462 power supplies, rating from 100 W to 1 MW. The very different output currents, from 10 A to 2300 A, and output voltages, from 8 V to 1300 V, imposed many different technical solution realized by the world industry. This paper describes the Power Supply System giving also a description of the different typologies, their characteristics and control systems. The paper reports also the power supply performances and gives information on their installation and first year operation period

Power supply system for the superconducting outsert of the CHMFL hybrid magnet

Science.gov (United States)

Fang, Z.; Zhu, J.; Chen, W.; Jiang, D.; Huang, P.; Chen, Z.; Tan, Y.; Kuang, G.

2017-12-01

The construction of a new hybrid magnet, consisting of a 11 T superconducting outsert and a 34 T resistive insert magnet, has been finished at the Chinese High Magnetic Field Laboratory (CHMFL) in Hefei. With a room temperature bore of 800 mm in diameter, the hybrid magnet superconducting outsert is composed of four separate Nb3Sn-based Cable-in-Conduit Conductor (CICC) coils electrically connected in series and powered by a single power supply system. The power supply system for the superconducting outsert consists of a 16 kA DC power supply, a quench protection system, a pair of 16 kA High Temperature Superconducting (HTS) current leads, and two Low Temperature Superconducting bus-lines. The design and manufacturing of the power supply system have been completed at the CHMFL. This paper describes the design features of the power supply system as well as the current fabrication condition of its main components.

Application of parallel connected power-MOSFET elements to high current d.c. power supply

International Nuclear Information System (INIS)

Matsukawa, Tatsuya; Shioyama, Masanori; Shimada, Katsuhiro; Takaku, Taku; Neumeyer, Charles; Tsuji-Iio, Shunji; Shimada, Ryuichi

2001-01-01

The low aspect ratio spherical torus (ST), which has single turn toroidal field coil, requires the extremely high d.c. current like as 20 MA to energize the coil. Considering the ratings of such extremely high current and low voltage, power-MOSFET element is employed as the switching device for the a.c./d.c. converter of power supply. One of the advantages of power-MOSFET element is low on-state resistance, which is to meet the high current and low voltage operation. Recently, the capacity of power-MOSFET element has been increased and its on-state resistance has been decreased, so that the possibility of construction of high current and low voltage a.c./d.c. converter with parallel connected power-MOSFET elements has been growing. With the aim of developing the high current d.c. power supply using power-MOSFET, the basic characteristics of parallel operation with power-MOSFET elements are experimentally investigated. And, the synchronous rectifier type and the bi-directional self commutated type a.c./d.c. converters using parallel connected power-MOSFET elements are proposed

Troubleshooting of signal power supply system for Shanghai metro line 7

Science.gov (United States)

Lu, Kaixia; Xiao, Jie

2018-03-01

With the rapid development of Urban Rail Transit Signal Technology, the demand of signal power supply system for signal equipment is higher and higher. The signal intelligent power supply panel is the main component of the urban rail traffic signal power supply system. Whether the intelligent power supply panel working or not is directly related to traffic safety. The maintenance of intelligent signal power supply panel is particularly important. Line 7 of Shanghai Metro adopts PMZG Signal Intelligent Power Supply Panel, which is produced by Beijing Jinyujiaxin Polytron Technologies Inc. Maintenance of power supply system mainly includes routine maintenance and troubleshooting. This article will make clear the routine maintenance contents of PMZG Signal Intelligent Power Supply Panel, and put forward the common fault information and troubleshooting methods of PMZG Signal Intelligent Power Supply Panel. In accordance with the steps of fault handling, the faults can be eliminated in the shortest possible time, and PMZG Signal Intelligent Power Supply Panel can be quickly restored to normal working state.

Environmental inventories for future electricity supply systems for Switzerland

International Nuclear Information System (INIS)

Dones, R.; Gantner, U.; Hirschberg, S.; Doka, G.; Knoepfel, I.

1996-02-01

This report provides the analysis of environmental inventories for selected electricity supply systems considered as possible options to meet the expected electricity demand in Switzerland in year 2030. The work was carried out by the Paul Scherrer Institute (PSI) and the Swiss Federal Institute of Technology Zurich (ETHZ), and was supported by the Swiss Association of Producers and Distributers of Electricity (VSE). Two possible electricity demand level cases were postulated by VSE, both under the basic assumption of economic growth: a high-growth demand case corresponding to a yearly increase of 2% from year 1995 to year 2010 and 1% from year 2010 to year 2030, and a low-growth demand case corresponding to a yearly increase of 1% from year 1995 to year 2010 and 0.5% from year 2010 to year 2030. The base (i.e. secured) supply in year 2030 will be, according to VSE, totally dominated by hydro with rather minor contributions from combined heat-and-power plants, small gas turbines, incinerators and solar photovoltaic plants. Due to decommissioning of the currently operating nuclear power plants and expiration of long-term electricity import contracts there will eventually occur a gap between the postulated electricity demand and the base supply. VSE provided seven options to cover this gap, defined in terms of mixes with different contributions from gas, coal, nuclear and solar chains; in this context a distinction is also made with respect to shares of domestic and imported electricity. The systems considered represent advanced technologies, regarded as either typical or most suitable for the Swiss conditions. System-specific input to the present analysis has been partially generated based on direct contacts with the industry. Life Cycle Analysis (LCA) was used to establish environmental inventories for the systems analysed. The analysis has been performed on three levels: 1) individually for each system considered, 2) comparison of systems, 3) comparison of supply

Refurbishment of the power supply and NMR systems

International Nuclear Information System (INIS)

Dugay, G.

1998-01-01

This paper summarises some of the first renovation performed on GANIL power converters, their control system and on magnetic field measurements. Among numerous actions undertaken the most important four, mentioned in the report are: remote control interfaces; current catchers; pulsed supplies; RMN system renovation

Low-noise pulse-mode current power supply for magnetic field measurements of magnets for accelerators

International Nuclear Information System (INIS)

Omel'yanenko, M.M.; Borisov, V.V.; Donyagin, A.M.; Kostromin, S.A.; Makarov, A.A.; Khodzhibagiyan, G.G.; Shemchuk, A.V.

2017-01-01

The described pulse-mode current power supply has been designed and fabricated for the magnetic field measurement system of superconducting magnets for accelerators. The power supply is based on a current regulator with pass transistor bank in linear mode. The output current pulses (0-100 A) are produced by using the energy of preliminary charged capacitor bank (5-40 V), which is charged additionally after each pulse. There is no AC-line frequency and harmonics ripple in the output current, the relative noise level is less than -100 dB (or 10 -5 ) of RMS value (it is defined as the ratio of output RMS noise current to the maximal output current 100 A within the operating bandwidth, expressed in dB).

Creation of reactor's reliable system of emergency energy supply

International Nuclear Information System (INIS)

Batyrbekov, G.A.; Brovkin, A.Yu.; Petukhov, V.K.; Chekushin, A.I.; Chernyaev, V.P.; Yagotinets, N.A.

1998-01-01

System of reliable power supply of the WWR-K reactor complex is described, which completely provides safety operation of reactor equipment in the case of total voltage loss from external power transmission lines as well as under destruction of accumulation batteries by earthquake more than 6 balls. Switching on in operation of diesel-generators and system of constant current supply from accumulator batteries is occurred automatically under cessation of voltage supply from centralized power system. Reliable reactor dampening in case it work on capacity has been ensured. Reactor cooling under its emergency shutdown during both the partial or the total loss of coolant in first counter has been carried out. Under full coolant loss the system of emergency reactor cooling has been switched on in operation

Limitations on current ripple of the power supplies for the SSC bending magnets

International Nuclear Information System (INIS)

Lebedev, V.A.

1993-01-01

Noise and ripple in the bending magnets of large proton collider cause the beam emittance growth and the luminosity degradation. The emittance growth due to voltage ripple of the bending magnets power supplies is studied. The role of the collider transverse feedback system is shown to be very important to facilitate the requirements to value of ripple. The longitudinal emittance growth due to slow variations of power supply current is studied as well. 9 refs.; 15 figs

Zijm Consortium: Engineering a Sustainable Supply Chain System

NARCIS (Netherlands)

Knofius, Nils; Rahimi Ghahroodi, Sajjad; van Capelleveen, Guido Cornelis; Yazdanpanah, Vahid

2018-01-01

In this paper we address one of the current major research areas of the Zijm consortium; engineering sustainable supply chain systems by transforming traditionally linear practices to circular systems. We illustrate this field of research with a case consisting of a network of three firms Willem

The imperative for stronger vaccine supply and logistics systems.

Science.gov (United States)

Zaffran, Michel; Vandelaer, Jos; Kristensen, Debra; Melgaard, Bjørn; Yadav, Prashant; Antwi-Agyei, K O; Lasher, Heidi

2013-04-18

With the introduction of new vaccines, developing countries are facing serious challenges in their vaccine supply and logistics systems. Storage capacity bottlenecks occur at national, regional, and district levels and system inefficiencies threaten vaccine access, availability, and quality. As countries adopt newer and more expensive vaccines and attempt to reach people at different ages and in new settings, their logistics systems must be strengthened and optimized. As a first step, national governments, donors, and international agencies have crafted a global vision for 2020 vaccine supply and logistics systems with detailed plans of action to achieve five priority objectives. Vaccine products and packaging are designed to meet the needs of developing countries. Immunization supply systems support efficient and effective vaccine delivery. The environmental impact of energy, materials, and processes used in immunization systems is minimized. Immunization information systems enable better and more timely decision-making. Competent and motivated personnel are empowered to handle immunization supply chain issues. Over the next decade, vaccine supply and logistics systems in nearly all developing countries will require significant investments of time and resources from global and national partners, donors, and governments. These investments are critical if we are to reach more people with current and newer vaccines. Copyright © 2012 Elsevier Ltd. All rights reserved.

Decentralized energy management strategy based on predictive controllers for a medium voltage direct current photovoltaic electric vehicle charging station

International Nuclear Information System (INIS)

Torreglosa, Juan P.; García-Triviño, Pablo; Fernández-Ramirez, Luis M.; Jurado, Francisco

2016-01-01

Highlights: • Electric vehicle charging station supplied by photovoltaic, batteries and grid connection is analyzed. • The bus voltage is the key parameter for controlling the system by decentralized approach. • Decentralized control approach facilities the enlargement of the system. • Photovoltaic and battery systems are controlled by model predictive controllers. • Response by model predictive controllers improves that by PI controllers. - Abstract: The use of distributed charging stations based on renewable energy sources for electric vehicles has increased in recent years. Combining photovoltaic solar energy and batteries as energy storage system, directly tied into a medium voltage direct current bus, and with the grid support, results to be an interesting option for improving the operation and efficiency of electric vehicle charging stations. In this paper, an electric vehicle charging station supplied by photovoltaic solar panels, batteries and with grid connection is analysed and evaluated. A decentralized energy management system is developed for regulating the energy flow among the photovoltaic system, the battery and the grid in order to achieve the efficient charging of electric vehicles. The medium voltage direct current bus voltage is the key parameter for controlling the system. The battery is controlled by a model predictive controller in order to keep the bus voltage at its reference value. Depending on the state-of-charge of the battery and the bus voltage, the photovoltaic system can work at maximum power point tracking mode or at bus voltage sustaining mode, or even the grid support can be needed. The results demonstrate the proper operation and energy management of the electric vehicle charging station under study.

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-07-01

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

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

Directory of Open Access Journals (Sweden)

Mahmood Movahedipour

2016-11-01

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

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

International Nuclear Information System (INIS)

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

2016-01-01

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

Magnet power supply system for the ALS storage ring and booster

International Nuclear Information System (INIS)

Jackson, L.T.; Luchini, K.; Lutz, I.

1993-05-01

The Magnet Power Supply System is described by specification, design, hardware, and operating experience. A unique system for the one Hz, 1.5 GeV Booster, where the wideband QF and QD power supplies track the dipole current to within 0.1% at injection will be detailed. AC distribution system considerations related to inverting the stored energy of the booster magnet back into power grid will be discussed. The rational for linear correctors and individual quad supplies (225 total units) will be placed within the context of the storage-ring requirements

Direct Quantification of Methane Emissions Across the Supply Chain: Identification of Mitigation Targets

Science.gov (United States)

Darzi, M.; Johnson, D.; Heltzel, R.; Clark, N.

2017-12-01

Researchers at West Virginia University's Center for Alternative Fuels, Engines, and Emissions have recently participated in a variety of studies targeted at direction quantification of methane emissions from across the natural gas supply chain. These studies included assessing methane emissions from heavy-duty vehicles and their fuel stations, active unconventional well sites - during both development and production, natural gas compression and storage facilities, natural gas engines - both large and small, two- and four-stroke, and low-throughput equipment associated with coal bed methane wells. Engine emissions were sampled using conventional instruments such as Fourier transform infrared spectrometers and heated flame ionization detection analyzers. However, to accurately quantify a wide range of other sources beyond the tailpipe (both leaks and losses), a full flow sampling system was developed, which included an integrated cavity-enhanced absorption spectrometer. Through these direct quantification efforts and analysis major sources of methane emissions were identified. Technological solutions and best practices exist or could be developed to reduce methane emissions by focusing on the "lowest-hanging fruit." For example, engine crankcases from across the supply chain should employ vent mitigation systems to reduce methane and other emissions. An overview of the direct quantification system and various campaign measurements results will be presented along with the identification of other targets for additional mitigation.

Operation of SST-1 TF power supply during SST-1 campaigns

International Nuclear Information System (INIS)

Sharma, Dinesh Kumar; Vora, Murtuza M.; Ojha, Amit; Singh, Akhilesh Kumar; Bhavsar, Chirag

2015-01-01

Highlights: • SST-1 TF power supply is 12 pulse SCR converter circuit. • TF power supply protection, measurement and control scheme are explained. • Quench, emergency and normal shot process is explained and results of SST-1 campaigns are shown. • Dynamic control of TF current. • The paper shows the results of last ten SST-1 campaigns. - Abstract: SST-1 TF power supply provides the direct current for the required magnetic field of TF coil. TF power supply includes transformer, 12-pulse converter, bus bar, water-cooled cable, protection and measuring equipments, and isolator, VME DAC system and GUI software. TF power supply is operated through GUI software built in TCL/Tk. VME DAC system monitors the parameters, provides On/Off commands, voltage and current references and initiates predefined reference to emergency shutdown. The emergency shutdown is hardwired to TF power supply from central control. During quench power supply converter opens DCCB and dump resistor is connected in the circuit and VME DAC system acquires bus bar voltage, dump voltage and dump current. Operation of TF power supply also requires monitoring of SCR and transformer temperature and water flow rate of water-cooled cable during high current long pulse shot. Before start up of TF power supply a quench simulation is performed to check the readiness of protection. This paper describes pre startup operation, normal shot operation, emergency and quench process, dynamic control and complete shutdown operation of TF power supply.

Operation of SST-1 TF power supply during SST-1 campaigns

Energy Technology Data Exchange (ETDEWEB)

Sharma, Dinesh Kumar, E-mail: dinesh@ipr.res.in; Vora, Murtuza M.; Ojha, Amit; Singh, Akhilesh Kumar; Bhavsar, Chirag

2015-10-15

Highlights: • SST-1 TF power supply is 12 pulse SCR converter circuit. • TF power supply protection, measurement and control scheme are explained. • Quench, emergency and normal shot process is explained and results of SST-1 campaigns are shown. • Dynamic control of TF current. • The paper shows the results of last ten SST-1 campaigns. - Abstract: SST-1 TF power supply provides the direct current for the required magnetic field of TF coil. TF power supply includes transformer, 12-pulse converter, bus bar, water-cooled cable, protection and measuring equipments, and isolator, VME DAC system and GUI software. TF power supply is operated through GUI software built in TCL/Tk. VME DAC system monitors the parameters, provides On/Off commands, voltage and current references and initiates predefined reference to emergency shutdown. The emergency shutdown is hardwired to TF power supply from central control. During quench power supply converter opens DCCB and dump resistor is connected in the circuit and VME DAC system acquires bus bar voltage, dump voltage and dump current. Operation of TF power supply also requires monitoring of SCR and transformer temperature and water flow rate of water-cooled cable during high current long pulse shot. Before start up of TF power supply a quench simulation is performed to check the readiness of protection. This paper describes pre startup operation, normal shot operation, emergency and quench process, dynamic control and complete shutdown operation of TF power supply.

Building sustainable supply chains: consumer choice or direct management?

Energy Technology Data Exchange (ETDEWEB)

Hebditch, David; Blackmore, Emma

2012-06-15

Putting a 'carbon label' on products to show how much carbon dioxide is emitted during their production, transport and disposal has been heralded as a powerful route to sustainability within companies' supply chains. Several leading firms have joined the Carbon Trust carbon labelling scheme over the past five years, including UK-based retail giant Tesco, which as early as 2007 promised to use carbon labels on all its products. But earlier this year, the multinational said it was dropping carbon labels and instead directly managing its supply chains. Many other companies are similarly choosing direct management over consumer choice as the most effective route to emission reductions. In so doing, they are shouldering greater responsibility for the emissions and impacts of their supply chains. But environmental concerns must not be allowed to trump development needs and companies must not unfairly disadvantage smaller-scale producers in developing countries.

Development of rapid detection system on BEPC Ⅱ magnet power supply

International Nuclear Information System (INIS)

Chen Suying; Zhan Mingchuan; Long Fengli; Ye Weidong

2014-01-01

To quickly find the causes of the accelerator unstable or lost beam caused by magnet power supply in Beijing Electron Positron Collider (BEPC Ⅱ) running, the rapid detection system for magnet power supply was developed. The stability of the system in 8 h is about 0.005%, and it can acquire over nearly 500 sets of magnet power supply current values most quickly in 0.33 ms. All data were written to the MySQL database in real time, so as to be able to quickly troubleshoot magnet power supply problem through historical data analysis and comparison. (authors)

Electrolytic tritium enrichment: Current control using current-stabilised Kepco Type JQE modular supplies

International Nuclear Information System (INIS)

1976-01-01

This note describes the principles, design and operation of a current-stabilised power source for tritium electrolytic enrichment cells. A Kepoo Tpe JE, modular supply is current-stabilised by controlled current feedback. The accompanying control unit incorporates a temperature sensor or the cooling unit of the electrolysis cells, a line monitor to register current shut-off due to temporary power failure, a time-of-day clock, a current control potentiometer and a digital voltmeter providing current reading to an accuracy of 0.01A

Electrolytic tritium enrichment: Current control using current-stabilised Kepco Type JQE modular supplies

Energy Technology Data Exchange (ETDEWEB)

NONE

1976-07-12

This note describes the principles, design and operation of a current-stabilised power source for tritium electrolytic enrichment cells. A Kepoo Tpe JE, modular supply is current-stabilised by controlled current feedback. The accompanying control unit incorporates a temperature sensor or the cooling unit of the electrolysis cells, a line monitor to register current shut-off due to temporary power failure, a time-of-day clock, a current control potentiometer and a digital voltmeter providing current reading to an accuracy of 0.01A.

Current Directional Protection of Series Compensated Line Using Intelligent Classifier

Directory of Open Access Journals (Sweden)

M. Mollanezhad Heydarabadi

2016-12-01

Full Text Available Current inversion condition leads to incorrect operation of current based directional relay in power system with series compensated device. Application of the intelligent system for fault direction classification has been suggested in this paper. A new current directional protection scheme based on intelligent classifier is proposed for the series compensated line. The proposed classifier uses only half cycle of pre-fault and post fault current samples at relay location to feed the classifier. A lot of forward and backward fault simulations under different system conditions upon a transmission line with a fixed series capacitor are carried out using PSCAD/EMTDC software. The applicability of decision tree (DT, probabilistic neural network (PNN and support vector machine (SVM are investigated using simulated data under different system conditions. The performance comparison of the classifiers indicates that the SVM is a best suitable classifier for fault direction discriminating. The backward faults can be accurately distinguished from forward faults even under current inversion without require to detect of the current inversion condition.

Future directions conventional oil supply, Western Canada

International Nuclear Information System (INIS)

Campbell, G.R.; Hayward, J.

1997-01-01

The history of the Canadian oil industry was briefly sketched and the future outlook for crude oil and natural gas liquids in western Canada was forecast. The historical review encompassed some of the significant events in history of the Canadian oil industry, including the Leduc discovery in 1947, the Swan Hills discovery in 1957, the start of commercial production from the Athabasca oil sands in 1967, the discovery of the Hibernia oilfield offshore Newfoundland in 1979, and the onset of the use of horizontal production wells in western Canada in 1987. The resource base, supply costs, and the technology that is being developed to reduce costs and to improve recovery, were reviewed. Future oil prices were predicted, taking into account the costs associated with technological developments. It was suggested that the character of the industry is undergoing a change from an industry dominated by conventional supply to a mixed industry with increasing volume of heavy oil, primary bitumen, synthetic oil and frontier supply replacing 'conventional' light crude oil. Projections into the future are subject to uncertainty both on the supply as well as on the demand side. The potential impact of technology can significantly affect demand, and technological developments can yield additional supplies which exceed current expectations. 10 figs

Circuitry for monitoring a high direct current voltage supply for an ionization chamber

International Nuclear Information System (INIS)

1981-01-01

An arrangement to measure the voltage of the supply and a switching means controlled by this is described. The voltage measurer consists of first and second signal coupling means, the input of the second (connected to the voltage supply) is connected in series with the output of the first. An ionization chamber with this circuitry may be used to monitor the radiation output of a particle accelerator more accurately. Faulty measurements of the dose output, caused by voltages in the earth circuit, are avoided. (U.K.)

A battery-powered high-current power supply for superconductors

CERN Document Server

Wake, M; Suda, K

2002-01-01

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

High voltage power supplies for INDUS-2 RF system

International Nuclear Information System (INIS)

Badapanda, M.K.; Hannurkar, P.R.

2003-01-01

The RF system of Indus-2 employs klystron amplifiers operating at 505.812 MHz. A precession controlled high voltage DC supply of appropriate rating is needed for each klystron amplifier, as its bias supply. Since internal flashover and arcing are common with the operation of these klystrons and stored energies beyond particular limit inside its bias power supply is detrimental to this device, a properly designed crowbar is incorporated between each klystron and its power supply. This crowbar bypass these stored energies and helps protecting klystron under any of these unfavorable conditions. In either case, power supply sees a near short circuit across its load. So, its power circuit is designed to reduce the fault current level and its various components are also designed to withstand these fault currents, as and when it appears. Finally, operation of these high voltage power supplies (HVPS) generates lot of harmonics on the source side, which distort the input waveform substantially and reduces the input power factor also. Source multiplication between two power supplies are planned to improve upon above parameters and suitable detuned line filters are incorporated to keep the input voltage total harmonics distortion (THD) below 5 % and input power factor (IFF) near unity. (author)

Alternatives for blocking direct current in AC system neutrals at the Radisson/LG2 complex

International Nuclear Information System (INIS)

Eitzmann, M.A.; Walling, R.A.; Sublich, M.; Kah, A.; Huynh, H.; Granger, M.; Dutil, A.

1992-01-01

Severe offset saturation results from the passage of direct current through power transformers. Such direct current can arise from geomagnetic disturbances, or resistive coupling of the substation ground to HVDC earth electrodes. This paper documents the development of alternative approaches for the design and application of blocking devices placed between transformer neutrals and the substation ground. System constraints on the impedance and overvoltage limitation of the neutral blocking device (NBD) are covered. Three alternative NBD schemes are developed and optimized. System performance of the NBD is discussed, as are the practical implementation considerations for this unconventional equipment application. Although the paper focuses on the NBD requirements of Hydro-Quebec's Radisson/LG2 complex, the fundamental information is applicable to any situation where dc must be clocked from a power transformer neutral in a system designed for effectively-grounded operation

Final Test of the W7-X Control Coils Power Supply and its Integration into the Overall Control Environment

International Nuclear Information System (INIS)

Fuellenbach, F.; Rummel, T.; Pingel, S.; Laqua, H.; Mueller, I.; Jauregi, E.

2006-01-01

In order to be able to vary the magnetic configuration of WENDELSTEIN 7-X (W7-X) at the plasma edge and allow sweeping of the power across the divertor target plates 10 '' control coils '' are installed inside the plasma vessel behind the baffle plates of the divertor. The coils are made of a hollow copper profile with eight turns each. The dimensions of the coils are 2,05 m x 0,35 m x 0,35 m with a three dimensional shape to fit into the narrow space between the baffles and the wall of the plasma vessel. Each of the ten coils is supplied by independent power supplies each providing bi-directionally a direct current of 2500 A with high accuracy and low ripple. To allow sweeping the power deposition from the plasma across the target plates the power supplies provide an alternating current of up to 625 A with frequencies up to 20 Hz which is synchronised between the ten supplies in order to maintain the symmetry of the magnetic field. The total output current of a power supply is a superposition of a direct current and an alternating current, where both parts have to be independently adjustable. JEMA, Spain provided the complete set of power supplies which are based on 10 independent four-quadrant power supplies with a link rectifier and includes a cooling water unit, a dedicated distribution and a central control and visualization system. All ten power supply units and auxiliary systems have meanwhile been installed and finally tested at the W7-X site in Greifswald. The paper focuses on the results of the final tests and measures to integrate the power supply system to the overall control system including the central PLC and PC's for experiment control, data acquisition- and security systems. (author)

A high-current, high-voltage power supply with special output current waveform for APS injector synchrotron dipole magnets

International Nuclear Information System (INIS)

Fathizadeh, M.; Despe, O.D.; McGhee, D.G.; Mills, F.E.; Turner, L.R.

1991-01-01

This paper describes a high-voltage, high-current power supply for the injector synchrotron dipole magnets at APS. In order to reset the dipole magnets in each cycle two different current waveforms are suggested. The first current waveform consists of three sections, namely: dc-reset, linear ramp, and recovery sections where injection is done ''on the fly''. The second current waveform consists of six different sections, dc-reset, transition to injection level, injection flat level, parabolic, linear ramp and recovery sections. The effect of such waveforms on the beam is discussed and the power supply limitations to follow such waveforms are given. The power supply limitations are due to the power components and control loops. The reference for the current loop is generated by a DAC which is discussed

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

International Nuclear Information System (INIS)

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

2008-01-01

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

MAGY: An innovative high voltage-low current power supply for gyrotron

International Nuclear Information System (INIS)

Siravo, Ugo; Alex, Juergen; Bader, Michael; Carpita, Mauro; Fasel, Damien; Gavin, Serge; Perez, Albert

2011-01-01

From the electrical point of view, the body and the anode of high power gyrotrons behave as capacitive loads. A highly dynamic power supply is, therefore, hard to achieve. The MAGY concept (Modulator for the Anode of a triode type GYrotron) embodies an innovative solution to manage the capacitive current ensuring a very low ripple on the output voltage. It consists of a series of independent, bi-directional and regulated DC sources. Compared to existing topologies, this solution requires a smaller number of power modules. It avoids internal high frequency modulation and simultaneously offers high resolution of the output voltage and a wide range of operating scenarios.

Pricing strategy in a dual-channel and remanufacturing supply chain system

Science.gov (United States)

Jiang, Chengzhi; Xu, Feng; Sheng, Zhaohan

2010-07-01

This article addresses the pricing strategy problems in a supply chain system where the manufacturer sells original products and remanufactured products via indirect retailer channels and direct Internet channels. Due to the complexity of that system, agent technologies that provide a new way for analysing complex systems are used for modelling. Meanwhile, in order to reduce the computational load of searching procedure for optimal prices and profits, a learning search algorithm is designed and implemented within the multi-agent supply chain model. The simulation results show that the proposed model can find out optimal prices of original products and remanufactured products in both channels, which lead to optimal profits of the manufacturer and the retailer. It is also found that the optimal profits are increased by introducing direct channel and remanufacturing. Furthermore, the effect of customer preference, direct channel cost and remanufactured unit cost on optimal prices and profits are examined.

Thyristor crowbar system for the high current power supplies of ASDEX upgrade

International Nuclear Information System (INIS)

Kaesemann, C.-P.; Lieshout, L. van; Huart, M.; Sihler, C.

2005-01-01

The ohmic heating system and the poloidal field coils of ASDEX upgrade are supplied by 15 thyristor converter units with an installed apparent power of 600 MVA. To protect the thyristor converters against dc overvoltage arising from abnormal operations and resulting damages caused by the large energy stored in the AUG magnet coils an overvoltage protection system was required. The paper describes the motivation for-and the design and testing of the thyristor crowbar system representing the thyristor converter overvoltage protection system. It will present the layout, analyse the results of measurements obtained during commissioning, compare them to the calculated (design) values and report on the first experience of operation on the AUG coils improving the safety of the equipment

Magnet power supply system for the ISABELLE half-cell prototype

International Nuclear Information System (INIS)

Nawrocky, R.J.

1977-01-01

Due to stringent requirements on the spatial harmonic content of ISABELLE's magnetic field, the magnet power supplies for the half-cell prototype must be dynamically accurate and stable to within 0.01% of their full-scale rating. Depending on the application, the full-scale current of various units comprising the system ranges from +-50 A to 4000 A. The system, as constructed is fully controllable and programmable either manually or with a control computer. The magnet power supply system described was constructed and interconnected with the half-cell computer control equipment. A number of power supply units were tested with inductive test loads in both the manual and the computer control modes. Test results on stability and speed of response indicate that all systems perform according to specifications

Using integrated information systems in supply chain management

Science.gov (United States)

Gonzálvez-Gallego, Nicolás; Molina-Castillo, Francisco-Jose; Soto-Acosta, Pedro; Varajao, Joao; Trigo, Antonio

2015-02-01

The aim of this paper is to empirically test not only the direct effects of information and communication technology (ICT) capabilities and integrated information systems (IS) on firm performance, but also the moderating role of IS integration along the supply chain in the relationship between ICT external and capabilities and business performance. Data collected from 102 large Iberian firms from Spain and Portugal are used to test the research model. The hierarchical multiple regression analysis is employed to test the direct effects and the moderating relationships proposed. Results show that external and internal ICT capabilities are important drivers of firm performance, while merely having integrated IS do not lead to better firm performance. In addition, a moderating effect of IS integration in the relationship between ICT capabilities and business performance is found, although this integration only contributes to firm performance when it is directed to connect with suppliers or customers rather than when integrating the whole supply chain.

Factors affecting the potential of direct load control for non-generating utilities. Final report. [Distribution and wholesale power supply interaction

Energy Technology Data Exchange (ETDEWEB)

None

1979-04-01

Several alternatives are available for achieving load management, including direct or voluntary control of customer loads, customer or utility energy storage systems for diurnal load shifting, and expanded interconnection and operation of electric power systems. All of these alternatives are available to the fully integrated (generating, transmitting and distributing) electric utility and the analysis of their effects encompasses the power supply and delivery system. However, the costs and benefits of the alternatives to the fully integrated electric utility are perhaps not so obvious. Therefore, by considering a non-generating utility, this analysis focuses upon the distribution system and wholesale power supply interaction as a step toward an analysis including the power supply and delivery system. This report develops an analysis procedure and discusses some of the relevant factors to be consdered in the application of direct load control for a non-generating utility system. The analysis concentrates on the distribution system only to determine the effect of rates and payback as a result of direct load control. Thus, the study is responsive to the specific needs of the non-generating utility. This analysis of direct load control encompasses the determination of those loads amenable to control, the selection of a suitable one-way communications system to rend control and the estimation of expected benefits and costs. The complementary functions to the application of direct load control such as automatic meter reading via the addition of a bi-directional communications system and voltage control are not included in the analysis but are detailed for future consideration.

Navy Telemedicine: Current Research and Future Directions

National Research Council Canada - National Science Library

Reed, Cheryl

2002-01-01

.... This report reviews military and civilian models for evaluating telemedicine systems in order to determine future directions for Navy telemedicine research within the current funding environment...

Accelerator magnet power supply using storage generator

International Nuclear Information System (INIS)

Karady, G.; Thiessen, H.A.

1987-01-01

Recently, a study investigated the feasibility of a large, 60 GeV accelerator. This paper presents the conceptual design of the magnet power supply (PS() and energy storage system. The main ring magnets are supplied by six, high-voltage and two, low-voltage power supplies. These power supplies drive a trapezoidal shaped current wave through the magnets. The peak current is 10 kA and the repetition frequency is 3.3 Hz. During the acceleration period the current is increased from 1040 A to 10,000 A within 50 msec which requires a loop voltage of 120 kV and a peak power of 1250 MW. During the reset period, the PS operates as an inverter with a peak power of -1250 MW. The large energy fluctuation necessitates the use of a storage generator. Because of the relatively high operation frequency, this generator operates in a transient mode which significantly increases the rotor current and losses. The storage generator is directly driven by a variable speed drive, which draws a practically constant power of 17 MW from the ac supply network and eliminates the pulse loading. For the reduction of dc ripple, the power supplies operate in a 24 pulse mode

Enhanced distributed energy resource system

Science.gov (United States)

Atcitty, Stanley [Albuquerque, NM; Clark, Nancy H [Corrales, NM; Boyes, John D [Albuquerque, NM; Ranade, Satishkumar J [Las Cruces, NM

2007-07-03

A power transmission system including a direct current power source electrically connected to a conversion device for converting direct current into alternating current, a conversion device connected to a power distribution system through a junction, an energy storage device capable of producing direct current connected to a converter, where the converter, such as an insulated gate bipolar transistor, converts direct current from an energy storage device into alternating current and supplies the current to the junction and subsequently to the power distribution system. A microprocessor controller, connected to a sampling and feedback module and the converter, determines when the current load is higher than a set threshold value, requiring triggering of the converter to supply supplemental current to the power transmission system.

Supply chain management models, applications, and research directions

CERN Document Server

Pardalos, Panos; Romeijn, H

2005-01-01

This work brings together some of the most up to date research in the application of operations research and mathematical modeling te- niques to problems arising in supply chain management and e-Commerce. While research in the broad area of supply chain management enc- passes a wide range of topics and methodologies, we believe this book provides a good snapshot of current quantitative modeling approaches, issues, and trends within the field. Each chapter is a self-contained study of a timely and relevant research problem in supply chain mana- ment. The individual works place a heavy emphasis on the application of modeling techniques to real world management problems. In many instances, the actual results from applying these techniques in practice are highlighted. In addition, each chapter provides important mana- rial insights that apply to general supply chain management practice. The book is divided into three parts. The first part contains ch- ters that address the new and rapidly growing role of the inte...

About economy of fuel and energy resources in the hot water supply system

Science.gov (United States)

Rotov, P. V.; Sivukhin, A. A.; Zhukov, D. A.; Zhukova, A. V.

2017-11-01

The assessment of the power efficiency realized in the current of heat supply system of technology of regulation of loading of the hot water supply system, considering unevenness consumption of hot water is executed. For the purpose of definition the applicability boundary of realized technology comparative analysis of indicators of the effectiveness of its work within the possible range of the parameters of regulations. Developed a software application “The calculation of the total economy of fuel and energy resources in the hot water supply system when you change of the parameters of regulations”, which allows on the basis of multivariate calculations analyses of their results, to choose the optimum mode of operation heat supply system and to assess the effectiveness of load regulation in the hot water supply system.

Control system for magnet power supplies for Novosibirsk free electron laser

International Nuclear Information System (INIS)

Velikanov, Y.M.; Veremeenko, V.F.; Vinokurov, N.A.; Galt, A.A.; Dovzhenko, B.A.; Kozak, V.R.; Kuper, E.A.; Medvedev, L.E.; Medvedko, A.S.; Serednyakov, S.S.

2012-01-01

A high-power free electron laser (FEL) based on the accelerator-recuperator principle is being built in Budker Institute (Russia). The magnetic system of the FEL is an important part of the installation. It consists of many magnetic elements of different types: bending magnets, quadrupole lenses and correctors. The windings of all these elements are fed from DC current power supplies. The power supply control system based on embedded intelligent controllers with the CAN-BUS interface is considered in detail. The control software structure and capabilities are described. Besides, the software tools for power supply diagnostics are described

Mouse housing system using pressurized cages intraventilated by direct-current microfans.

Science.gov (United States)

Martinewski, Alexandre; Correia, Caio S C; de Souza, Nívea L; Merusse, José L B

2012-03-01

We performed the initial assessment of an alternative pressurized intraventilated (PIV) caging system for laboratory mice that uses direct-current microfans to achieve cage pressurization and ventilation. Twenty-nine pairs of female SPF BALB/c mice were used, with 19 experimental pairs kept in PIV cages and 10 control pairs kept in regular filter-top (FT) cages. Both groups were housed in a standard housing room with a conventional atmospheric control system. For both systems, intracage temperatures were in equilibrium with ambient room temperature. PIV cages showed a significant difference in pressure between days 1 and 8. Air speed (and consequently airflow rate) and the number of air changes hourly in the PIV cages showed decreasing trends. In both systems, ammonia concentrations increased with time, with significant differences between groups starting on day 1. Overall, the data revealed that intracage pressurization and ventilation by using microfans is a simple, reliable system, with low cost, maintenance requirements, and incidence of failures. Further experiments are needed to determine the potential influence of this system on the reproductive performance and pulmonary integrity in mice.

Research on assurance system of nuclear fuel supply (Contract research)

International Nuclear Information System (INIS)

Kobayashi, Naoki; Naoi, Yosuke; Wakabayashi, Shuji; Tazaki, Makiko; Senzaki, Masao

2010-03-01

Assurance of supply (AOS) of nuclear fuel is a special arrangement in case of nuclear fuel supply disruption caused by political reasons other than nonproliferation. It aims to support a stable supply of nuclear fuel while avoiding unnecessary spread of sensitive enrichment technology. Current discussions on AOS have been initiated by the IAEA Director-General's article published in The Economist entitled 'Towards a Safer World' Oct. 2003. Since then, various proposals on AOS have been presented. In order to facilitate international discussions on AOS, authors have conducted studies of AOS system based on Japanese Government's proposal 'IAEA Standby Arrangement System (INFCIRC/683)'. In this paper, we gave an overview of discussions on AOS since World War II, and elaborated on some of current proposals. We have been able to discuss feasibility of AOS system more specifically by including additional costs and period required for AOS, and to present a system which could work as a practical system. Issues we have tried to tackle here include definitions of AOS, and roles of consumer states, supplier states, IAEA and nuclear industries. We present some solutions including broadening coverage of AOS, declaration by supplier states on AOS, establishing advisory committee in the IAEA on the actual application of AOS, and setting up an IAEA fund for AOS. (author)

Adoption of photovoltaic power supply systems: A study of key determinants in India

Energy Technology Data Exchange (ETDEWEB)

Peter, Raja [Department of Management and Enterprise Development, Massey University, Private Box 756, Wellington (New Zealand); Dickie, Laurence [Teaching and Learning, Research, CBS - International Programs, Curtin Business School, Curtin University of Technology, Western Australia (Australia); Peter, Vasanthi M. [Whitireia Polytechnic, Wellington (New Zealand)

2006-11-15

This paper examines the key determinants that foster the adoption of photovoltaic (PV) power supply systems. The authors provide empirical evidence which suggest that 'government initiatives' and institutional 'finance' are important influencers of the decision to adopt PV power supply systems in developing countries. In order to diffuse PV technology it is also necessary to provide decision-makers with opportunities for direct and vicarious experience of PV systems through 'demonstration sites'. These factors have been ignored in earlier models of the innovation-decision process formulated by Rogers and the new innovation-decision framework proposed by Kaplan. Governments need to play a leadership role, and this coupled with the availability of Finance and Demonstration Sites will result in an increased interest leading to the adoption of PV technology in India. This research has led to the identification of variables such as the government initiatives, demonstration sites and finance, which are critical to the adoption of PV systems in developing countries like India. The research provided empirical evidence that is currently lacking in the area of adoption of PV technology in developing countries. (author)

Abort kicker power supply systems at Fermilab

International Nuclear Information System (INIS)

Krafczyk, G.; Dugan, G.; Harrison, M.; Koepke, K.; Tilles, E.

1985-01-01

Over the past several years, Fermilab has been operating with a single turn proton abort system in both the superconducting Tevatron and the conventional Main Ring. The abort kicker power supply for this system discharges a lumped capacitance into the inductive magnet load, causing the beam to enter the abort channel. A unique feature of this design is the high voltage, high current diode assembly used to clip the recharge of the capacitor bank. This allows the current to decay slowly with the L/R time constant of the magnet and diode series combination. Special attention will be given to the diode characteristics needed for this passive switching element. Operational experience and proposed upgrades will be given for the two operational systems

On the optimization of the magneto-plasma compressor power supply system

OpenAIRE

Deshko, K. I.; Chernikov, V. A.

2018-01-01

The work of the miniature magneto-plasma compressor with the low-voltage power supply system was studied experimentally and the current and discharge voltage drop were measured. It was found that the voltage drop (a few tens of volts) remains practically constant during discharge. Performed electrical analysis allowed to determine the power efficiency of the supply system depending on the initial capacitor voltage, the discharge voltage and circuit parameters (capacitance, inductance, resista...

Control system of power supply for resistance welding machine

Directory of Open Access Journals (Sweden)

Світлана Костянтинівна Поднебенна

2017-06-01

Full Text Available This article describes the existing methods of heat energy stabilizing, which are realized in thyristor power supplies for resistance welding machines. The advantages and features of thyristor power supplies have been described. A control system of power supply for resistance welding machine with stabilization of heat energy in a welding spot has been developed. Measurements are performed in primary winding of a welding transformer. Weld spot heating energy is calculated as the difference between the energy, consumed from the mains, and the energy losses in the primary and secondary circuits of the welding transformer as well as the energy losses in the transformer core. Algorithms of digital signal processing of the developed control system are described in the article. All measurements and calculations are preformed automatically in real-time. Input signals to the control system are: transformer primary voltage and current, temperature of the welding circuit. The designed control system ensures control of the welding heat energy and is not influenced by the supply voltage and impedance changes caused by insertion of the ferromagnetic mass in the welding circuit, the temperature change during the welding process. The developed control system for resistance welding machine makes it possible to improve the quality of welded joints, increase the efficiency of the resistance welding machine

HIV vaccines: current challenges and future directions.

Science.gov (United States)

Avrett, Sam; Collins, Chris

2002-07-01

Volume seven of the Review will mark the tenth anniversary of the Canadian HIV/AIDS Legal Network with a series of articles that describe past developments and future directions in several areas of policy and law related to HIV/AIDS. The following article is the first of these, discussing current challenges and future directions in the development of and access to HIV vaccines. It argues that governments are under public health, ethical, and legal obligations to develop and provide access to HIV vaccines. It further explains what is required for governments to fulfill their obligations: additional commitment and resources for HIV vaccine development in the context of increased global research and development regarding diseases of the poor; increased support and advocacy for partnerships to develop HIV vaccines; enhanced regulatory capacity in every country to review, approve, and monitor HIV vaccines; and assurance of global supply of, procurement of, delivery of, and access to vaccines in the context of efforts to increase global access to public health measures and technologies.

Medical Robots: Current Systems and Research Directions

Directory of Open Access Journals (Sweden)

Ryan A. Beasley

2012-01-01

Full Text Available First used medically in 1985, robots now make an impact in laparoscopy, neurosurgery, orthopedic surgery, emergency response, and various other medical disciplines. This paper provides a review of medical robot history and surveys the capabilities of current medical robot systems, primarily focusing on commercially available systems while covering a few prominent research projects. By examining robotic systems across time and disciplines, trends are discernible that imply future capabilities of medical robots, for example, increased usage of intraoperative images, improved robot arm design, and haptic feedback to guide the surgeon.

Ecology, Economy and security of supply of the Dutch Electricity Supply System. A scenario based future analysis

International Nuclear Information System (INIS)

Roedel, J.G.

2008-01-01

The Dutch electricity sector has been transformed into a liberalized international energy market. Market players are free to choose from various electricity generation options when replacing or expanding production capacity. However, choices that are made now will influence emissions (ecology), integral costs (economy) and availability (security of supply) for the next 25 - 40 years. This thesis shows if and how, based on the current electricity supply system, an optimal balance of ecology, economy and security of supply can be achieved. First, the current electricity supply system is described to create a frame of reference. Then, future technological developments are described for electricity production options. Four potential scenarios are constructed featuring various uncertainties: the globalising versus the local economy; priority versus subordination for the environment; and the security/insecurity of the fuel supply. These four scenarios are worked out with a specially developed techno-economic simulation model; the results are analysed in terms of ecology, economy and security of supply. The findings indicate that it is impossible to arrive at an optimal balance for the defined scenarios. Scenarios with a low environmental impact lead to high integral costs and vice versa. However, by applying a smart combination of various modern generation technologies, CO2 capture and storage, the deployment of biomass and the re-use of residual heat it is possible to reach an optimal balance whereby the additional integral costs can be kept under control compared with the lowest-cost scenarios. To achieve this, clear growth and incentive guidelines need to be established for the various production options. This thesis will form a good starting point for that exercise

AC power supply systems

International Nuclear Information System (INIS)

Law, H.

1987-01-01

An ac power supply system includes a rectifier fed by a normal ac supply, and an inverter connected to the rectifier by a dc link, the inverter being effective to invert the dc output of the receiver at a required frequency to provide an ac output. A dc backup power supply of lower voltage than the normal dc output of the rectifier is connected across the dc link such that the ac output of the rectifier is derived from the backup supply if the voltage of the output of the inverter falls below that of the backup supply. The dc backup power may be derived from a backup ac supply. Use in pumping coolant in nuclear reactor is envisaged. (author)

Inductive-pulsed power supplying system for a betatron electromagnet

International Nuclear Information System (INIS)

Otrubyannikov, Yu.A.; Safronov, A.S.

1984-01-01

Circuit of producing quasitriangular current pulses designed for the pulsed power supply system of betatron electromagnet is described. Introduction of additional winding into electromagnet provides circuit galvanic isolation, artificial commutation of basic circuit thyristors and inductive power input to the winding during thyristor commutation. The considered system is used for excitation of betatron electromagnet up to 18 MeV. Magnetic field energy equals 1100 Y. The maximal voltage in energy storage capacitor - 4.8 kV. Current amplitude in basic winding - 335 A. The number of loops in basic winding equals 80, in additional one - 32. Current pulse duration in electromagnet-3.8 ms. The system provides operation with controlled current pulse frequency from 0 up to 150 Hz. The maximal consumption power - 18 kW

Evaluation of simplified ventilation system with direct air supply through the facade in a school in a cold climate

Energy Technology Data Exchange (ETDEWEB)

Mysen, M. [Norwegian Building Research Institute, Blindern, Oslo (Norway); Department of Energy and Process Technology, Norwegian University of Science and Technology (NTNU), Trondheim (Norway); Schild, P. G.; Hellstrand, V.; Thunshelle, K. [Norwegian Building Research Institute, Blindern, Oslo (Norway)

2004-07-01

Many educational buildings in industrialised countries have poor indoor climate, according to today's knowledge about the impact of indoor climate on well-being and productivity. Budget restrictions and practical limitations such as lack of space for central air handling units and ventilation ducts, have motivated the application of simplified ventilation systems in some schools, such as taking unconditioned supply air directly from the facade. One such school was recently evaluated in Norway. On cold days, thermal comfort in the classroom deteriorated due to cold down draught from the supply outlet. In addition, moist and fertile conditions for microbiological growth were observed in the air supply ductwork. On the other hand the same pupils are more satisfied with the school and have less sick building syndrome (SBS) symptoms during winter than summer. An improved control strategy with a temperature-compensated CO{sub 2} set-point for controlling the air flow is suggested. This could improve thermal comfort and reduce energy use without compromising perceived air quality (PAQ) during cold weather. Furthermore it could improve indoor air quality (IAQ) during warm weather with only a slight increase of energy use. Further evaluation of an improved solution is needed before such a ventilation concept can be recommended in cold climates. (author)

Electric power system / emergency power supply

International Nuclear Information System (INIS)

Dorn, P.G.

1980-01-01

One factor of reliability of reactor safety systems is the integrity of the power supply. The purpose of this paper is a review and a discussion of the safety objectives required for the planning, licensing, manufacture and erection of electrical power systems and components. The safety aspects and the technical background of the systems for - the electric auxiliary power supply system and - the emergency power supply system are outlined. These requirements result specially from the safety standards which are the framework for the studies of safety analysis. The overall and specific requirements for the electrical power supply of the safety systems are demonstrated on a 1300 MW standard nuclear power station with a pressurized water reactor. (orig.)

Method for exciting inductive-resistive loads with high and controllable direct current

International Nuclear Information System (INIS)

Hill, H.M. Jr.

1976-01-01

The apparatus and method for transmitting dc power to a load circuit by applying a dc voltage from a standard waveform synthesizer to duration modulate a bipolar rectangular wave generator are described. As the amplitude of the dc voltage increases, the widths of the rectangular wave generator output pulses increase, and as the amplitude of the dc voltage decreases, the widths of the rectangular wave generator output pulses decrease. Thus, the waveform synthesizer selectively changes the durations of the rectangular wave generator bipolar output pulses so as to produce a rectangular wave ac carrier that is duration modulated in accordance with and in direct proportion to the voltage amplitude from the synthesizer. Thereupon, by transferring the carrier to the load circuit through an amplifier and a rectifier, the load current also corresponds directly to the voltage amplitude from the synthesizer. To this end, the rectified wave at less than 100 percent duty factor amounts to a doubled frequency direct voltage pulse train for applying a direct current to the load, while the current ripple is minimized by a high L/R in the load circuit. In one embodiment, a power transmitting power amplifier means having a dc power supply is matched to the load circuit through a transformer for current magnification without sacrificing load current duration capability, while negative voltage and current feedback are provided in order to insure good output fidelity. 4 Claims, 18 Drawing Figures

High-voltage direct current (HVDC) transmission - a key technology for our power supply

International Nuclear Information System (INIS)

Dorn, J.

2016-01-01

The phasing-out of nuclear power in some countries and the aspirations of reducing carbon dioxide emissions have far-reaching implications for electric power generation in Europe. In the future, renewable electricity generation will account for a considerable share of the energy mix, but this type of production is often far from the load centers. In Germany, for example, large quantities of wind energy are already generated in the north and in the North Sea, but large load centers are located several hundred kilometers south of there. This requires an expansion of the transmission network with innovative solutions. High-voltage direct-current (HVDC) transmission plays an important role, since it brings a number of advantages over conventional AC technology and makes certain requirements feasible, for example Cable transmission over longer distances. The lecture presents the advantages of HVDC, the semiconductors used as well as the basic functions and typical performance of the used converter topopologies. The plant configurations and main components are illustrated using current projects. (rössner) [de

Supply risk analysis: applying system dynamics to the Colombian healthcare sector

Directory of Open Access Journals (Sweden)

Juan Pablo Zamora Aguas

2013-09-01

Full Text Available This paper addresses supply risk in the oncological medicine supply chain (SC in Colombia. A system dynamics model was developed for assessing supply risk impact on SC operation and performance. The costs of risk and logis-tics operation were evaluated in current conditions and in a risk mitigation scenario. The model was based on a systematic analysis of supply networks, mainly concerning the reduction of overall SC costs and improving service, quality and opportunity performance index. This article has resulted from research into SC risk management (SCRM carried out by the Universidad Nacional de Colombia’s SEPRO research group.

Realization of toroidal field power supply control system for J-TEXT tokamak

International Nuclear Information System (INIS)

Qiu Shengshun; Zhuang Ge; Zhang Ming; Feng Jianming

2009-01-01

Based on the integrated development environment provided by QNX real-time operation system, the control system of toroidal field power supply is designed and developed. The system is proved to be reliable, stable and in real-time. It can control the power supply successfully to produce a constant current up to 92.5kA lasting for 1s and 1.74T at the magnetic axis. In conclusion, the control system can meet the requirements of the J-TEXT routine operation at present. (authors)

Air conditioning system and component therefore distributing air flow from opposite directions

Science.gov (United States)

Obler, H. D.; Bauer, H. B. (Inventor)

1974-01-01

The air conditioning system comprises a plurality of separate air conditioning units coupled to a common supply duct such that air may be introduced into the supply duct in two opposite flow directions. A plurality of outlets such as registers or auxiliary or branch ducts communicate with the supply duct and valve means are disposed in the supply duct at at least some of the outlets for automatically channelling a controllable amount of air from the supply duct to the associated outlet regardless of the direction of air flow within the supply duct. The valve means comprises an automatic air volume control apparatus for distribution within the air supply duct into which air may be introduced from two opposite directions. The apparatus incorporates a freely swinging movable vane in the supply duct to automatically channel into the associated outlet only the deflected air flow which has the higher relative pressure.

Supply Chain Systems Architecture and Engineering Design: Green-field Supply Chain Integration

OpenAIRE

Radanliev, P

2015-01-01

This paper developed a new theory for supply chain architecture, and engineering design that enables integration of the business and supply chain strategies. The architecture starts with individual supply chain participants and derives insights into the complex and abstract concept of green-field integration design. The paper presented a conceptual system for depicting the interactions between business and supply chain strategy engineering. The system examines the decisions made when engineer...

A Review of the Wood Pellet Value Chain, Modern Value/Supply Chain Management Approaches, and Value/Supply Chain Models

OpenAIRE

Hughes, Natalie M.; Shahi, Chander; Pulkki, Reino

2014-01-01

We reviewed 153 peer-reviewed sources to provide identification of modern supply chain management techniques and exploration of supply chain modeling, to offer decision support to managers. Ultimately, the review is intended to assist member-companies of supply chains, mainly producers, improve their current management approaches, by directing them to studies that may be suitable for direct application to their supply chains and value chains for improved efficiency and profitability. We found...

Parameter Improved Particle Swarm Optimization Based Direct-Current Vector Control Strategy for Solar PV System

Directory of Open Access Journals (Sweden)

NAMMALVAR, P.

2018-02-01

Full Text Available This paper projects Parameter Improved Particle Swarm Optimization (PIPSO based direct current vector control technology for the integration of photovoltaic array in an AC micro-grid to enhance the system performance and stability. A photovoltaic system incorporated with AC micro-grid is taken as the pursuit of research study. The test system features two power converters namely, PV side converter which consists of DC-DC boost converter with Perturbation and Observe (P&O MPPT control to reap most extreme power from the PV array, and grid side converter which consists of Grid Side-Voltage Source Converter (GS-VSC with proposed direct current vector control strategy. The gain of the proposed controller is chosen from a set of three values obtained using apriori test and tuned through the PIPSO algorithm so that the Integral of Time multiplied Absolute Error (ITAE between the actual and the desired DC link capacitor voltage reaches a minimum and allows the system to extract maximum power from PV system, whereas the existing d-q control strategy is found to perform slowly to control the DC link voltage under varying solar insolation and load fluctuations. From simulation results, it is evident that the proposed optimal control technique provides robust control and improved efficiency.

Design and simulation for the pulse high-voltage DC power supply (HVPS) of 1.2 MW/2.45 GHz HT-7U lower hybrid current drive system

International Nuclear Information System (INIS)

Huang Yiyun; Kuang Guangli; Xu Weihua; Liu Baohua; Lin Jianan; Wu Junshuan; Zheng Guanghua; Yang Chunshen

2000-01-01

The superconducting tokamak HT-7U has been designed by the Institute of Plasma Physics since 1998 and will be set up before 2003. The 1.2 MW/2.45 GHz HT-7U LHCD (Lower hybrid current drive) system which being the most efficient non-induction device can heat the plasma and drive the plasma current has been efficiently in operation now, and a particular design of the 2.8 MW/-35 kV high-voltage DC power supply has been already completed and will apply to the klystron of LHCD on HT-7 and the future HT-7U, and the project of the power supply has been examined and approved professionally by an authorized group of high-level specialist in the Institute of Plasma Physics. The detailed design of the power supply and the simulation results are referred

Electrical supply for MFTF-B superconducting magnet system

International Nuclear Information System (INIS)

Shimer, D.W.; Owen, E.W.

1985-01-01

The MFTF-B magnet system consists of 42 superconducting magnets which must operate continuously for long periods of time. The magnet power supply system is designed to meet the operational requirements of accuracy, flexibility, and reliability. The superconducting magnets require a protection system to protect against critical magnet faults of quench, current lead overtemperature, and overcurrent. The protection system is complex because of the large number of magnets, the strong coupling between magnets, and the high reliability requirement. This paper describes the power circuits and the components used in the design

Regulated-current dc power supply for gaseous-discharge lamps

Science.gov (United States)

Freeman, W.; Huguenin, D.

1970-01-01

Controlled current source having a high output resistance feeds continuous-flow hydrogen lamps in vacuum-ultraviolet photometric equipment. The power supply, also used with low-pressure sealed lamps, has a short recovery time and smooth regulation without overshoot.

THREE-PHASE ENERGY SUPPLY SYSTEMS SIMULATION FOR THE TOTAL POWER LOSSES COMPONENTS ASSESSMENT

Directory of Open Access Journals (Sweden)

D.V. Tugay

2016-09-01

Full Text Available Purpose. The goal is to optimize a structure of Matlab-model of the three-phase energy supply system with power active filter. The mathematical model that describes the energy supply system modes of operation which contains additional losses is proposed. Methodology. We have applied concepts of the electrical circuits theory, mathematical modeling elements based on linear algebra and vector calculus, mathematical simulation in Matlab package. Results. We have developed two models of three-phase energy supply system. The first one is based on a vector representation, and the second one on the matrix representation of energy processes. Using these models we have solved the problem of maintaining unchanged the average useful power for 279 cases of energy supply system modes of operation. Originality. We have developed methods of mathematical analysis of a three-phase energy supply systems with polyharmonic voltages and currents in the symmetric and asymmetric modes. Practical value. We have created Matlab-model of a three-phase energy supply system with automated calculation of a correction factor. It allows reducing more than one order the time for energy processes elucidation in multiphase systems.

Energy-saving implications from supply chain improvement: An exploratory study on China's consumer goods retail system

International Nuclear Information System (INIS)

Wang, Xi; Cai, Hua; Florig, H. Keith

2016-01-01

Despite significant public attentions to green supply chain management, few studies have explicitly addressed the energy implications of consumer-goods supply surplus, especially in developing countries like China. This study explored the energy-saving potential from improving supply chain efficiencies and reducing excess inventory in China's retail system from a life-cycle perspective. Through embodied energy analysis, we found that energy invested pre-manufacture contributed 80–95% of the total energy embodied in consumer products. Although embodied energy intensities had declined by 60–90% since the mid-1990s, the lessened marginal improvements implied that 'low hanging fruits' have largely been captured, and the search for new opportunities for energy-saving is in demand. Positive correlations between total economic inputs and embodied energy in consumer goods indicated possible synergy effect between cost-reduction and energy-saving in supply system management. And structural path analysis identified sector-specific energy management priorities for each retail-related sector. This study suggested that improving supply chain efficiencies provides a promising supplement to China's current industrial energy-efficient projects which target reducing direct energy use per se as an intra-firm cost-saving measure. From the life-cycle perspective, the definition of 'green sector' might have to be reconsidered in China towards a more energy-efficient economy and society.

Optics Supply Planning System

International Nuclear Information System (INIS)

Gaylord, J.

2009-01-01

The purpose of this study is to specify the design for an initial optics supply planning system for NIF, and to present quality assurance and test plans for the construction of the system as specified. The National Ignition Facility (NIF) is a large laser facility that is just starting operations. Thousands of specialized optics are required to operate the laser, and must be exchanged over time based on the laser shot plan and predictions of damage. Careful planning and tracking of optic exchanges is necessary because of the tight inventory of spare optics, and the long lead times for optics procurements and production changes. Automated inventory forecasting and production planning tools are required to replace existing manual processes. The optics groups members who are expected to use the supply planning system are the stakeholders for this project, and are divided into three groups. Each of these groups participated in a requirements specification that was used to develop this design. (1) Optics Management--These are the top level stakeholdersk, and the final decision makers. This group is the interface to shot operations, is ultimately responsible for optics supply, and decides which exchanges will be made. (2) Work Center Managers--This group manages the on site optics processing work centers. They schedule the daily work center operations, and are responsible for developing long term processing, equipment, and staffing plans. (3) Component Engineers--This group manages the vendor contracts for the manufacture of new optics and the off site rework of existing optics. They are responsible for sourcing vendors, negotiating contracts, and managing vendor processes. The scope of this analysis is to describe the structure and design details of a system that will meet all requirements that were described by stakeholders and documented in the analysis model for this project. The design specifies the architecture, components, interfaces, and data stores of the system

Load Torque Compensator for Model Predictive Direct Current Control in High Power PMSM Drive Systems

DEFF Research Database (Denmark)

Preindl, Matthias; Schaltz, Erik

2010-01-01

In drive systems the most used control structure is the cascade control with an inner torque, i.e. current and an outer speed control loop. The fairly small converter switching frequency in high power applications, e.g. wind turbines lead to modest speed control performance. An improvement bring...... the use of a current controller which takes into account the discrete states of the inverter, e.g. DTC or a more modern approach: Model Predictive Direct Current Control (MPDCC). Moreover overshoots and oscillations in the speed are not desired in many applications, since they lead to mechanical stress...

System redesign of the immunization supply chain: Experiences from Benin and Mozambique.

Science.gov (United States)

Prosser, Wendy; Jaillard, Philippe; Assy, Emmanuelle; Brown, Shawn T; Matsinhe, Graça; Dekoun, Mawutondji; Lee, Bruce Y

2017-04-19

Evidence suggests that immunization supply chains are becoming outdated and unable to deliver needed vaccines due to growing populations and new vaccine introductions. Redesigning a supply chain could result in meeting current demands. The Ministries of Health in Benin in Mozambique recognized known barriers to the immunization supply chain and undertook a system redesign to address those barriers. Changes were made to introduce an informed push system while consolidating storage points, introducing transport loops, and increasing human resource capacity for distribution. Evaluations were completed in each country. Evaluation in each country indicated improved performance of the supply chain. The Effective Vaccine Management (EVM) assessment in Benin documented notable improvements in the distribution criteria of the tool, increasing from 40% to 100% at the district level. In Mozambique, results showed reduced stockouts at health facility level from 79% at baseline to less than 1% at endline. Coverage rates of DTP3 also increased from 68.9% to 92.8%. Benin and Mozambique are undertaking system redesign in order to respond to constraints identified in the vaccine supply chain. Results and learnings show improvements in supply chain performance and make a strong case for system redesign. These countries demonstrate the feasibility of system redesign for other countries considering how to address outdated supply chains. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Two-section linear direct-current accelerator of 1.2 MeV electrons. Mean beam current of 50 mA

International Nuclear Information System (INIS)

Alimov, A.S.; Ermakov, D.I.; Ishkhanov, B.S.; Shvedunov, V.I.; Sakharov, V.P.; Trower, W.P.

2002-01-01

The theoretical and experimental results, obtained by simulation, creation and start-up of the two-section linear electron accelerator, are presented. The following beam parameters: beam current of 49 mA, mean energy of 1.2 MeV, of 59 kV, normalized emittance of 11 mm mrad are determined on the basis of the data on the beam dynamics simulation and the accelerating structure optimization. Special attention is paid to the choice of the version of the SHF-supply system of the two-section accelerator. The version of the SHF-supply system, based on the sections phasing, operating in the auto-oscillation model by means of the synchronizing signal from the feedback chain of the first section into the feedback chain of the second section, is considered. The electron beam parameters on the accelerator outlet (beam current - 44 mA, beam energy - 1.15 MeV, beam efficiency - 50.6 kW) proved to be close to the simulation results [ru

High performance current controller for particle accelerator magnets supply

DEFF Research Database (Denmark)

Maheshwari, Ram Krishan; Bidoggia, Benoit; Munk-Nielsen, Stig

2013-01-01

The electromagnets in modern particle accelerators require high performance power supply whose output is required to track the current reference with a very high accuracy (down to 50 ppm). This demands very high bandwidth controller design. A converter based on buck converter topology is used...

Constant-current charging supplies for the Advanced Photon Source (APS) linear accelerator modulators

International Nuclear Information System (INIS)

Fuja, R.; Grelick, A.E.; Meyer, D.

1997-01-01

The APS linac beam energy must be stable to within ±1% to match the energy acceptance of the positron accumulator ring. The klystron pulse modulators must therefore provide a pulse-to-pulse repeatability of 0.1% in order for the beam to have the required energy stability. The modulators have had difficulty achieving the necessary repeatability since the pulse forming network (PFN) charging scheme does not include a deQing circuit. Several of the major charging circuit components are also less reliable than desired. In order to increase operating reliability and to improve pulse-to-pulse stability, it is planned to replace the high voltage power supplies in all modulators with constant-current power supplies. A new modulator charging supply that contains two EMI series 303 constant-current power supplies was constructed. Each of these EMI supplies delivers 1.5 A at up to 40 kV. One supply is sufficient for linac operation at up to 45 Hz, and two supplies in parallel enable linac operation at the nominal rf repetition rate of 60 Hz. This paper discusses test results from the new modulator, and also describes the existing modulators and their performance limitations

Exploring current and projected tradeoffs between hydropower profitability and reliability of supply in the Alps

Science.gov (United States)

Anghileri, D.; Castelletti, A.; Burlando, P.

2015-12-01

The recent spreading of renewable energy across Europe and the associated production variability and uncertainty are emerging challenges for hydropower system operation. Widely distributed and highly intermittent solar and wind power generation systems, along with feed-in-tariffs, at which they are remunerated, are threating the operation of traditional hydropower systems. For instance, in countries where the transition to a larger production by means of renewable power systems is a novel process, e.g. Switzerland, many hydropower companies are operating their reservoirs with low or no profits, claiming for a revision of the entire energy market system. This situation goes along with the problem of ensuring energy supply both nowadays and in the future, with changing energy demand and available water resources. In this work, we focus on a hydropower system in the Swiss Alps to explore how different operating policies can cope with both adequate energy supply and profitable operation under current and future climate and socio-economic conditions. We investigate the operation of the Mattmark reservoir in South-West Switzerland. Mattmark is a pumped reservoir of 98 106 m3 fed by a natural catchment of 37 km2 and contributing catchments, summing up to 51 km2, connected by several diversion channels. The hydrological regime, snow- and ice-melt dominated, has already experienced changes in the last decades due to glacier retreat and is expected to be strongly impacted by climate change in the future. We use Multi-Objective optimization techniques to explore current tradeoffs between profitability and secure supply. We then investigate how tradeoffs may evolve in time under different climate change projections and energy market scenarios. Results inform on the co-evolution of climate- and socio-economic induced variations, thus unveiling potential co-benefit situations to hydropower generation and providing insights to future energy market design.

Transcranial cerebellar direct current stimulation and transcutaneous spinal cord direct current stimulation as innovative tools for neuroscientists

Science.gov (United States)

Priori, Alberto; Ciocca, Matteo; Parazzini, Marta; Vergari, Maurizio; Ferrucci, Roberta

2014-01-01

Two neuromodulatory techniques based on applying direct current (DC) non-invasively through the skin, transcranial cerebellar direct current stimulation (tDCS) and transcutaneous spinal DCS, can induce prolonged functional changes consistent with a direct influence on the human cerebellum and spinal cord. In this article we review the major experimental works on cerebellar tDCS and on spinal tDCS, and their preliminary clinical applications. Cerebellar tDCS modulates cerebellar motor cortical inhibition, gait adaptation, motor behaviour, and cognition (learning, language, memory, attention). Spinal tDCS influences the ascending and descending spinal pathways, and spinal reflex excitability. In the anaesthetised mouse, DC stimulation applied under the skin along the entire spinal cord may affect GABAergic and glutamatergic systems. Preliminary clinical studies in patients with cerebellar disorders, and in animals and patients with spinal cord injuries, have reported beneficial effects. Overall the available data show that cerebellar tDCS and spinal tDCS are two novel approaches for inducing prolonged functional changes and neuroplasticity in the human cerebellum and spinal cord, and both are new tools for experimental and clinical neuroscientists. PMID:24907311

Scaling up antiretroviral therapy in Uganda: using supply chain management to appraise health systems strengthening

Directory of Open Access Journals (Sweden)

Neuhann Florian

2011-08-01

Full Text Available Abstract Background Strengthened national health systems are necessary for effective and sustained expansion of antiretroviral therapy (ART. ART and its supply chain management in Uganda are largely based on parallel and externally supported efforts. The question arises whether systems are being strengthened to sustain access to ART. This study applies systems thinking to assess supply chain management, the role of external support and whether investments create the needed synergies to strengthen health systems. Methods This study uses the WHO health systems framework and examines the issues of governance, financing, information, human resources and service delivery in relation to supply chain management of medicines and the technologies. It looks at links and causal chains between supply chain management for ART and the national supply system for essential drugs. It combines data from the literature and key informant interviews with observations at health service delivery level in a study district. Results Current drug supply chain management in Uganda is characterized by parallel processes and information systems that result in poor quality and inefficiencies. Less than expected health system performance, stock outs and other shortages affect ART and primary care in general. Poor performance of supply chain management is amplified by weak conditions at all levels of the health system, including the areas of financing, governance, human resources and information. Governance issues include the lack to follow up initial policy intentions and a focus on narrow, short-term approaches. Conclusion The opportunity and need to use ART investments for an essential supply chain management and strengthened health system has not been exploited. By applying a systems perspective this work indicates the seriousness of missing system prerequisites. The findings suggest that root causes and capacities across the system have to be addressed synergistically to

Scaling up antiretroviral therapy in Uganda: using supply chain management to appraise health systems strengthening.

Science.gov (United States)

Windisch, Ricarda; Waiswa, Peter; Neuhann, Florian; Scheibe, Florian; de Savigny, Don

2011-08-01

Strengthened national health systems are necessary for effective and sustained expansion of antiretroviral therapy (ART). ART and its supply chain management in Uganda are largely based on parallel and externally supported efforts. The question arises whether systems are being strengthened to sustain access to ART. This study applies systems thinking to assess supply chain management, the role of external support and whether investments create the needed synergies to strengthen health systems. This study uses the WHO health systems framework and examines the issues of governance, financing, information, human resources and service delivery in relation to supply chain management of medicines and the technologies. It looks at links and causal chains between supply chain management for ART and the national supply system for essential drugs. It combines data from the literature and key informant interviews with observations at health service delivery level in a study district. Current drug supply chain management in Uganda is characterized by parallel processes and information systems that result in poor quality and inefficiencies. Less than expected health system performance, stock outs and other shortages affect ART and primary care in general. Poor performance of supply chain management is amplified by weak conditions at all levels of the health system, including the areas of financing, governance, human resources and information. Governance issues include the lack to follow up initial policy intentions and a focus on narrow, short-term approaches. The opportunity and need to use ART investments for an essential supply chain management and strengthened health system has not been exploited. By applying a systems perspective this work indicates the seriousness of missing system prerequisites. The findings suggest that root causes and capacities across the system have to be addressed synergistically to enable systems that can match and accommodate investments in

Transcranial Direct Current Stimulation in Tinnitus Patients: A Systemic Review and Meta-Analysis

Directory of Open Access Journals (Sweden)

Jae-Jin Song

2012-01-01

Full Text Available Although transcranial direct current stimulation (tDCS has already been used to manage tinnitus patients, paucity of reports and variations in protocols preclude a comprehensive understanding. Hence, we conducted a meta-analysis based on systemic review to assess effectiveness of tDCS in tinnitus management and to compare stimulation parameters. PubMed was searched for tDCS studies in tinnitus. For randomized controlled trials (RCTs, a meta-analysis was performed. A total of 17 studies were identified and 6 of them were included in the systemic review and 2 RCTs were included in the meta-analysis. Overall 39.5% responded to active tDCS with a mean tinnitus intensity reduction of 13.5%. Additionally, left temporal area (LTA and bifrontal tDCS indicated comparable results. Active tDCS was found to be more effective than sham tDCS for tinnitus intensity reduction (Hedges' g=.77, 95% confidence interval 0.23–1.31. The efficacy of tDCS in tinnitus could not be fully confirmed by the current study because of the limited number of studies, but all studies included in the current systemic review and meta-analysis demonstrated significant tinnitus intensity improvement. Therefore, tDCS may be a promising tool for tinnitus management. Future RCTs in a large series regarding the efficacy as well as the comparison between LTA- and bifrontal tDCS are recommended.

Foreign Direct Investment and Energy Supply in the Middle East and North Africa: A Correlational Study

Science.gov (United States)

Elghali, Siddig

Middle East and North Africa countries have been criticized for failing to utilize foreign direct investment energy resources efficiently. The changing of energy resources environment of the past decades with its growing emphasis on the importance of imminent energy supply challenges require strategists to consider different types of energy resources investment to improve energy supply. One type of energy investment will show effectiveness and efficiency in utilizing foreign direct investment in exposing RE, fossil fuels, natural gas, and reducing CO2 emissions. The purpose of this quantitative correlational study was to utilize foreign direct investment to predict total primary energy supply in the Middle East and North Africa region between 1971 and 2013. The study was conducted using a sample size of 43 years of energy supply resources and foreign direct investment from 1971 to 2013, which includes all of the years for which FDI is available. RE potential may equip Middle East and North Africa countries with sustainable and clean electricity for centuries to come, as non-renewable energy resources may not meet the demands globally and domestically or environmentally. As demands for fossil fuels grow, carbon emissions will increase. RE may be a better option of CO 2 emissions sequestration and will increase electricity to rural areas without government subsidies and complex decision-making policies. RE infrastructure will reduce water desalinization costs, cooling systems, and be useful in heating. Establishing concentrated solar power may be useful for the region cooperation, negotiations, and integration to share this energy. The alternative sought to fossil fuels was nuclear power. However, nuclear power depends on depleting, non-renewable uranium resources. The cost of uranium will increase if widely used and the presence of a nuclear plant in an unstable region is unsafe. Thus, renewable energy as a long-term option is efficient. A nonlinear regression

Building a new control system for the cyclotron power supplies

International Nuclear Information System (INIS)

Kormany, Z.; Lakatos, T.; Kovacs, P.; Szuecs, I.; Ander, I.

2000-01-01

Complete text of publication follows. The MGC cyclotron of the ATOMKI is a multi-particle and variable-energy machine with a rather complicated beam transport system. As a consequence, the current or voltage value of numerous power supplies should be set and adjusted by the operators during a typical run. The original control system of the cyclotron provides a traditional control desk for this purpose where the requested values can be set by using selector switches and up/down tumblers. The adjustment process with this system is completely manual and rather slow - every power supply unit gets its starting value one after the other and it typically takes 10 to 20 minutes to change the whole setting. Another disadvantage of the present system is the poor reproducibility / the analogue panel meters of the control desk cannot provide the required precision to exactly repeat a former setting. To overcome the above difficulties and speed up the adjustment process of the cyclotron and the beam transport lines, a new control system for the power supplies has been designed and is under implementation within the framework of our modernization project. Supported by the International Atomic Energy Agency, Technical Assistance Program - Project Code Number: HUN/4/013. The control of the power supplies will be changed to digital - the analogue control signals of the power stages will be produced by the D/A, the current and voltage values will be read by the A/D conversion modules of a programmable logic controller (PLC). The transition to digital control requires the development of special interface units. To separate completely the control and measuring channels from each other, they are isolated from the PLC-ground by applying opto-isolators. A two-channel (control and measurement) linear interface circuit built around the TIL 300 optical isolators has been designed, assembled and tested. It has been verified that the linearity and the precision of this circuit fulfills the

Legal boundary conditions for direct marketing of 'green current' according to EEG 2012; Rechtliche Rahmenbedingungen fuer die Direktvermarktung von ''Gruenstrom'' nach dem EEG 2012

Energy Technology Data Exchange (ETDEWEB)

Breuer, Daniel [Landgericht Koeln (Germany); Osborne Clarke, Koeln (Germany). Bereich Energierecht

2012-07-01

The new direct marketing regime of the EEG 2012 provides incentives for operators of renewables-based systems to leave the fixed reimbursement scheme and integrate their systems in the markets, especially in the context of marketing of regulating power. However, it remains to be seen if this will reduce the cost of regulating energy supply, or at least keep it at the current level. In any case, plant operators should be careful in choosing their direct marketers and other partners and consultants. Simultaneous supply of regulating power is attractive especially for controllable and in some cases also for fluctuating renewable energy sources. This does comply with the priority principle and also with the prohibition of double marketing as is clearly stated in SEction 8 No. 3a.

Drug supply strategies, constraints and prospects in Nigeria.

Science.gov (United States)

Yusuff, K B; Tayo, F

2004-12-01

The study set out to identify the strategies for public drug supply in Nigeria, assess its functionality, and recommend appropriate means to ensure regular availability of safe, efficacious, good quality and affordable essential drugs at public health facilities. The investigation was carried out at the Directorate of Pharmaceutical services, Federal Ministry of Health (F.M.O.H) Abuja and Federal Medical Stores, Oshodi, Lagos. Semi-structured interview was conducted with key informants at the Department of Food & Drugs, Drug procurement unit and Central Medical store using structured questionnaires and direct informants answers. Our study shows that public drug supply in Nigeria is governed by a National Drug Policy (NDP) which was introduced in 1990 and it is yet to be reviewed after ten years. We also identified the Central Medical Store (CMS) system as the current public drug supply strategy in Nigeria. Public drug supply is mainly financed by governments and this is inadequate to ensure sustained availability of essential drugs. The major procurement methods in use are open tender and direct procurement. These methods as presently operated suffer from late order placement, delay in payment and poor supplier lead-time mainly attributable to lateness in payment for previous drug supplies. These have contributed to stock out of essential drugs at public health facilities. Major losses due to expiration and spoilage are recorded at both central and peripheral storage points despite adequacy of storage facilities and personnel. Road transportation was the major mode of drug distribution from central to peripheral storage points and shortage of vehicle was a key factor affecting drug distribution. There was an apparent lack of a functioning drug management information system to effectively coordinate public drug supply and there are no definite systems that monitor and evaluate staff performance. The CMS strategy currently used for public drug supply in Nigeria has

Maintenance management of emergency power supply equipment (uninterruptible power supply) in Tokai reprocessing plant

International Nuclear Information System (INIS)

Nishida, Kyosuke; Hiyama, Hisao; Shibata, Satomi; Iwasaki, Shogo; Inami, Shinichi

2009-01-01

Uninterruptible power supply systems are installed in the Tokai reprocessing plant in preparation for the emergency case that the commercial power supply is stopped by an accidental or intentional interruption in the supply of electricity. The uninterruptible power supply system particularly provides a temporary power source to the important devices for the radiation control of nuclear critical monitoring in the plant. Thus, the system is potentially important and essential for nuclear plants. The paper reports the current activities such as regular inspections, replacement of parts and system update, to maintain the function of uninterruptible power supply systems. (author)

The Role of Information Security Management Systems in Supply Chain Performance Improvement

Directory of Open Access Journals (Sweden)

Mohammad Reza Taghva

2012-02-01

Full Text Available In recent years, the researchers have emphasized on positive effect of information system on supply chain performance such as organizational processes integration, information sharing, information technology, etc. In other hand, information security management system is one of the subjects that researches considered its effects on increase accuracy and effective information exchange, access to accurate and timely information and reduce errors of information system. Since, any research has not been done on this ground (the importance of ISMS on supply chain performance. Therefore, it was felt that a research should have done on these approaches on supply chain. In this respect, current research was seeking that how ISMS had impact on supply chain performance in automotive industry and this was the innovative aspect of this paper. So first of all, after the review of the information security management system literature, supply chain performance was considered by the balanced scorecard approach then the most important factors of these two subjects was extracted by correlation analysis. In this way, it was considered that how ISMS had impact on supply chain performance by correlation analysis. The results showed that different dimensions of ISMS (information uniformity, prevent the human and machine mistake, information be accuracy, and rectitude and instruction for users had impact on four dimensions of supply chain performance (customers, financial, internal processes and learning and growth in three levels (strategic, technical, and operational in supply chain. At the end, it was showed that ISMS lays the ground for increase supply chain performance.

Research on assurance system of nuclear fuel supply (Contract research)

International Nuclear Information System (INIS)

Kobayashi, Naoki; Naoi, Yosuke; Wakabayashi, Shuji; Tazaki, Makiko; Senzaki, Masao

2010-08-01

Assurance of supply (AOS) of nuclear fuel is a special arrangement in case of nuclear fuel supply disruption caused by political reasons other than nonproliferation. It aims to support a stable supply of nuclear fuel while avoiding spread of sensitive enrichment technology. Current discussions on AOS have been initiated by the IAEA Director-General's article published in The Economist entitled 'Towards a Safer World' Oct. 2003. Since then, various proposals on AOS have been presented. In order to facilitate international discussions on AOS, authors have conducted studies of AOS system based on Japanese Government's proposal 'IAEA Standby Arrangement System (INFCIRC/683)'. In this paper, we have been able to discuss feasibility of AOS system more specifically by including additional costs and period required for AOS, and to present a system which could work as a practical system. Issues we have tried to tackle here include definitions of AOS, and roles of consumer States, supplier States, IAEA and nuclear industries. We present some solutions including broadening coverage of AOS, declaration by supplier States on AOS, establishing advisory committee in the IAEA on the actual application of AOS, and setting up an IAEA fund for AOS. (author)

Automated Water Supply System and Water Theft Identification Using PLC and SCADA

OpenAIRE

Prof. Anubha Panchal,; Ketakee Dagade

2014-01-01

In today’s world rapid growing urban residential areas, to avoid scarcity of water problems and requirements of consumers, therefore it is supposed to supply adequate water distribution networks are managed automatically. Along with this another problem in the water supply system is that public is using suction pumps to suck the water directly from the home street pipeline. The best way to improve the automation and monitoring architectures which contain a supervision and contr...

Current state and future direction of computer systems at NASA Langley Research Center

Science.gov (United States)

Rogers, James L. (Editor); Tucker, Jerry H. (Editor)

1992-01-01

Computer systems have advanced at a rate unmatched by any other area of technology. As performance has dramatically increased there has been an equally dramatic reduction in cost. This constant cost performance improvement has precipitated the pervasiveness of computer systems into virtually all areas of technology. This improvement is due primarily to advances in microelectronics. Most people are now convinced that the new generation of supercomputers will be built using a large number (possibly thousands) of high performance microprocessors. Although the spectacular improvements in computer systems have come about because of these hardware advances, there has also been a steady improvement in software techniques. In an effort to understand how these hardware and software advances will effect research at NASA LaRC, the Computer Systems Technical Committee drafted this white paper to examine the current state and possible future directions of computer systems at the Center. This paper discusses selected important areas of computer systems including real-time systems, embedded systems, high performance computing, distributed computing networks, data acquisition systems, artificial intelligence, and visualization.

Co-ordination of directional overcurrent protection with load current for parallel feeders

Energy Technology Data Exchange (ETDEWEB)

Wright, J.W.; Lloyd, G.; Hindle, P.J. [Alstom, Inc., Stafford (United Kingdom). T and D Protection and Control

1999-11-01

Directional phase overcurrent relays are commonly applied at the receiving ends of parallel feeders or transformer feeders. Their purpose is to ensure full discrimination of main or back-up power system overcurrent protection for a fault near the receiving end of one feeder. This paper reviews this type of relay application and highlights load current setting constraints for directional protection. Such constraints have not previously been publicized in well-known text books. A directional relay current setting constraint that is suggested in some text books is based purely on thermal rating considerations for older technology relays. This constraint may not exist with modern numerical relays. In the absence of any apparent constraint, there is a temptation to adopt lower current settings with modern directional relays in relation to reverse load current at the receiving ends of parallel feeders. This paper identifies the danger of adopting very low current settings without any special relay feature to ensure protection security with load current during power system faults. A system incident recorded by numerical relays is also offered to highlight this danger. In cases where there is a need to infringe the identified constraints an implemented and testing relaying technique is proposed.

A current-controlled PWM bipolar power supply for a magnet load

International Nuclear Information System (INIS)

Kang, Y.G.; McGhee, D.G.

1994-01-01

The Advanced Photon Source, at Argonne National Laboratory will produce the world's brightest x-ray beams when it is complete. A number of correction magnets are used to maintain proper beam position. Basically, two different types of bipolar power supplies are used for all the correction magnets: one requires dc correction only, and the other requires dc and ac correction. Normally linear-mode power amplifiers would be used for the bipolar power supplies. However, linear-mode power amplifiers dissipate a substantial amount of power as heat, resulting in poor efficiency for their large size. In addition, most commercial bipolar power supplies are linear-mode and available for lower power levels. Therefore, for higher power levels it was necessary to design a bipolar power supply that uses switch-mode power conversion. This paper describes a control technique for a pulse-width-modulatcd bipolar power supply, which can deliver a controlled current, dc plus ac to a correction magnet. A design example of a 150A bipolar power supply is presented

Calibration of Water Supply Systems Based on Ant Colony Optimization

Directory of Open Access Journals (Sweden)

Mahmoud Faghfoor Maghrebi

2013-03-01

Full Text Available Leakage is one of the main problems in the water supply systems and due to the limitations in water supply and its costly process, reduction of leak in water distribution networks can be considered as one of the main goals of the water supply authorities. One of the leak detection techniques in water distribution system is the usage of the recorded node pressures at some locations to calibrate the whole system node pressures. Calibration process is accomplished by the optimization of a constrained objective function. Therefore, in addition to performing a hydraulic analysis of the network, application of an optimization technique is needed. In the current paper, a comparsion between the ant colony and genetic algorithm methodes, in calibration of the node pressures and leak detections was investigated. To examine the workability and the way of leak detection, analysis of the network with an assumed leak was carried out. The results showed that the effectiveness of the ant colony optimization in the detection of the position and magnitude of leak in a water network.

NETWORK CENTRISM OPTIMIZATION OF EXPEDITIOUS SERVICE OF ELEMENTS OF THE POWER SUPPLY SYSTEM

Directory of Open Access Journals (Sweden)

Ye.I. Sokol

2016-06-01

Full Text Available Purpose. Development of precision selection criteria of options of technical realization of effective active and adaptive system of expeditious service of elements of a power supply system in the conditions of network-centric management. Methodology. In development of power supply systems their evolution from the elementary forms using elementary network technologies and models of interactions in power to more irregular shapes within the concept of Smart Grid with elements of network-centric character is observed. This direction is based on Internet-technologies of the last generation, and realize models of power activity which couldn't be realized before. Results. The number of possible options of active and adaptive system of expeditious service of elements of a power supply system is usually rather big and it is difficult to choose the acceptable option by direct search. Elimination of admissible options of the technical realization constructed on the principles of a network centrism means application of the theory of multicriteria optimization from a position of discrete programming. The basis of procedure of elimination is made by algorithm of an assessment of system by criterion of accuracy. Originality. The case of an assessment of the precision characteristic of system at restrictions for the set accuracy is connected with need of decomposition of requirements of all system in general and on separate subsystems. For such decomposition the ratios connecting the accuracy of functioning of a separate subsystem with variations of parameters of all system, and also with precision characteristics of subsystems of the lower levels influencing this subsystem are received. Practical value. In the conditions of the network-centric organization of management of expeditious service of elements of a power supply system elimination of options of subsystems when using precision criterion allows to receive the maximum number of essentially possible

Magnet power supply for ISABELLE

International Nuclear Information System (INIS)

Nawrocky, R.J.; Frankel, R.F.; Thomas, M.G.

1979-01-01

The power supply system which will energize the superconducting magnets in the ISABELLE machine consists of some 520 computer-programmable power supplies with outputs ranging from 50 A to 4500 A. Most of the power supplies will be used for the correction of field harmonics, orbit correction and adjustment of the machine working line. During acceleration, currents in various magnet correction coils will be controlled in real time to track the main field; all power supplies must be highly stable during the stacking and storage of the beam (in some cases current regulation must be in the order of 0.001%). PS reference programs will be stored in microprocessor based function generators embedded in each power supply. Due to the large amount of stored energy in the system, the magnets must be protected during quenches. Details of the power supply and of the magnet quench protection system are described

Bipolar programmable current supply for superconducting nuclear magnetic resonance magnets

Science.gov (United States)

Koivuniemi, Jaakko; Luusalo, Reeta; Hakonen, Pertti

1998-09-01

In high resolution continuous-wave nuclear magnetic resonance (NMR) work well-reproducible, linear sweeps of current are needed. We have developed a microcontroller based programmable current supply, tested with superconducting magnets with inductance of 10 mH and 10 H. We achieved a resolution and noise of 4 ppm. The supply has an internal sweep with programmable ramping rate and a possibility for remote operation from a computer with either GPIB or RS232 interface. It is based on an 18-bit D/A converter. The maximum output current is ±10 A, the sweep rate can be set between 1 μA/s-140 mA/s, and the maximum output voltage is ±2.5 V. In work at ultralow temperatures, especially in superconducting quantum interference device NMR, all rf interference to the experiment should be avoided. One of the sources of this kind of unwanted input is the digital switching noise of fast logic devices. We discuss this problem in the context of our design.

Energy efficient direct current distribution in commercially used buildings with smart power link to the AC distribution grid; Energieeffiziente Gleichstromverteilung in kommerziell genutzten Gebaeuden mit intelligenter Kopplung zum Niederspannungsnetz

Energy Technology Data Exchange (ETDEWEB)

Weiss, Roland [Siemens AG, Erlangen (Germany); Boeke, Ulrich [Philips Group Innovation-Research, Eindhoven (Netherlands); Maurer, Wilhelm [Infineon Technologies AG, Neubiberg (Germany); Zeltner, Stefan [Fraunhofer-Inst. fuer Integrierte Systeme und Bauelementetechnologie (IISB), Erlangen (Germany)

2012-07-01

The joint undertaking ''Direct Current Components and Grid'' (DCC+G) takes on the strategic challenge to reduce energy consumption and thus the reduction of CO{sub 2} emission caused by commercially used buildings through research in the fields of Direct Current distribution at a voltage level of {+-} 380 V. The major energy consumers in commercially used buildings, ready for the ''net-zero-energy'' goal of the European Union, are heat pumps for heating, ventilation systems, air conditioning units, cooling units (HVAC), lighting systems and information technology. All these components and subsystems have in common, that the most efficient versions would benefit from a direct current supply. Additionally the local producers of electric energy like photovoltaic systems usually generate DC-current. A Direct Current distribution grid within buildings would avoid the repeating conversion from DC and AC an vice versa and therefore reduce conversion losses. Important components of a direct current distribution grid are central, smart, high efficient, bidirectional rectifiers replacing the large number of small, less efficient rectifiers used today. Such large central rectifiers units could additionally be used to actively improve the power quality of the smart local AC distribution grid. One major part of the described activities is to show energy savings of about 5 % of electrical energy with a 2-phase direct current distribution grid using a voltage level of {+-} 380 V. (orig.)

Geothermal heat-pump systems of heat supply

International Nuclear Information System (INIS)

Vasil'ev, G.P.

2004-01-01

The data on the multilayer operation of the objects, located in the climatic conditions of the central area of Russia and equipped with the geothermal heat-pumping systems of the heat supply are presented. The results of the analytical studies on evaluating the geothermal heat-pumping systems of the heat supply integration efficiency into the structure of the energy supply system, prevailing in the country, are presented [ru

Hardwood lumber supply chain: current status and market opportunities

Science.gov (United States)

Urs Buehlmann; Matthew Bumgardner; Al Schuler; Mark Barford

2007-01-01

The membership of the Appalachian Hardwood Manufacturers Association was surveyed in 2005 to determine the current status of large Appalachian sawmills. The primary focus was to assess the impacts of globalization on primary manufacturing, but attention was also paid to general issues affecting the hardwood lumber supply chain-from concerns over forest health and log...

Evolution of competencies of logistics and supply chain managers

Directory of Open Access Journals (Sweden)

2010-09-01

Full Text Available One new concept emerging in current business reality is a virtual supply chain. This paper indicates in what way a virtual supply chain, that is subject to constant changes, influences the requirements for competencies of managerial staff in that specific business environment operating with discontinuities, temporary character, focus on customers, geographical dispersion, intensive support of IT systems, network structure and an extensive use of key competencies of their members. The paper presents the concept of virtual supply chain and results of research conducted in order to determine how current knowledge and skills of decision-makers fit into that concept. In that sense the quality of human resources, connected to logistics operations and management, has been examined from the point of view of the directions of required changes in the area of adequate qualifications and competencies for efficient management of virtual supply chains. Research was be based on a survey, conducted in 2010 and aiming at identification of skills and qualifications of logistics personnel in average Polish companies. Results of the study indicated that logistics qualifications of managerial personnel in Polish companies are constantly improving. Requirements of virtualisation of logistics and supply chain business result in a modified patterns of logistics professional carriers and new challenges for education and training systems.

Supply and demand analysis of the current and future US neurology workforce.

Science.gov (United States)

Dall, Timothy M; Storm, Michael V; Chakrabarti, Ritashree; Drogan, Oksana; Keran, Christopher M; Donofrio, Peter D; Henderson, Victor W; Kaminski, Henry J; Stevens, James C; Vidic, Thomas R

2013-07-30

This study estimates current and projects future neurologist supply and demand under alternative scenarios nationally and by state from 2012 through 2025. A microsimulation supply model simulates likely career choices of individual neurologists, taking into account the number of new neurologists trained each year and changing demographics of the neurology workforce. A microsimulation demand model simulates utilization of neurology services for each individual in a representative sample of the population in each state and for the United States as a whole. Demand projections reflect increased prevalence of neurologic conditions associated with population growth and aging, and expanded coverage under health care reform. The estimated active supply of 16,366 neurologists in 2012 is projected to increase to 18,060 by 2025. Long wait times for patients to see a neurologist, difficulty hiring new neurologists, and large numbers of neurologists who do not accept new Medicaid patients are consistent with a current national shortfall of neurologists. Demand for neurologists is projected to increase from ∼18,180 in 2012 (11% shortfall) to 21,440 by 2025 (19% shortfall). This includes an increased demand of 520 full-time equivalent neurologists starting in 2014 from expanded medical insurance coverage associated with the Patient Protection and Affordable Care Act. In the absence of efforts to increase the number of neurology professionals and retain the existing workforce, current national and geographic shortfalls of neurologists are likely to worsen, exacerbating long wait times and reducing access to care for Medicaid beneficiaries. Current geographic differences in adequacy of supply likely will persist into the future.

Direct-Current Forced Interruption and Breaking Performance of Spiral-Type Contacts in Aero Applications

Directory of Open Access Journals (Sweden)

Wenlei Huo

2017-05-01

Full Text Available This paper analyses the transient characteristics and breaking performance of direct-current (DC forced-interruption vacuum interrupters in 270 V power-supply systems. Three stages are identified in forced interruption: the DC-arcing stage, current-commutation stage, and voltage-recovery stage. During the current-commutation stage, the reverse peak-current coefficient k, which is a key design factor, is used to calculate the rate of current at zero-crossing (di/dt. MATLAB/Simulink simulation models are established to obtain the transient characteristics influenced by the forced-commutation branch parameters and the coefficient k. To study the breaking performance of spiral-type contacts, experiments are conducted for different contact materials and arcing times for currents less than 3.5 kA. During the DC-arcing stage, a locally intensive burning arc is observed in the CuW80 contact; however, it is not observed in the CuCr50 contact. On examining the re-ignition interruption results of the CuW80 contact, the intensive burning arc is found to be positioned within a possible re-ignition region. When the arcing time is longer than 1 ms, the intensive burning arc occurs and affects the breaking performance of the spiral-type contacts. If the DC-arcing stage is prolonged, the total arcing energy increases, which leads to a lower breaking capacity.

Design study of an AC power supply system in JT-60SA

International Nuclear Information System (INIS)

Shimada, Katsuhiro; Baulaigue, Olivier; Cara, Philippe; Coletti, Alberto; Coletti, Roberto; Matsukawa, Makoto; Terakado, Tsunehisa; Yamauchi, Kunihito

2011-01-01

In the initial research phase of JT-60SA, which is the International Thermonuclear Experimental Reactor (ITER) satellite Tokamak with superconducting toroidal and poloidal magnetic field coils, the plasma heating operation of 30 MW-60 s or 20 MW-100 s is planned for 5.5 MA single null divertor plasmas. To achieve this operation, AC power source of the medium voltage of 18 kV and ∼7 GJ has to be provided in total to the poloidal field coil power supplies and additional heating devices such as neutral beam injection (NBI) and electron cyclotron radio frequency (ECRF). In this paper, the proposed AC power supply system in JT-60SA was estimated from the view point of available power, and harmonic currents based on the standard plasma operation scenario during the initial research phase. This AC power supply system consists of the reused JT-60 power supply facilities including motor generators with flywheel, AC breakers, harmonic filters, etc., to make it cost effective. In addition, the conceptual design of the upgraded AC power supply system for the ultimate heating power of 41 MW-100 s in the extended research phase is also described.

A new high current laboratory and pulsed homopolar generator power supply at the University of Texas

Science.gov (United States)

Floyd, J. E.; Aanstoos, T. A.

1984-03-01

The University of Texas at Austin is constructing a facility for research in pulse power technology for the Center for Electromechanics at the Balcones Research Center. The facility, designed to support high-current experiments, will be powered by six homopolar generators, each rated at 10 MJ and arranged to allow matching the requirements of resistive and inductive loads at various voltage and current combinations. Topics covered include the high bay, the power supply configuration and parameters, the speed and field control, and the magnetic circuit. Also considered are the removable air-cooled brushes, the water-cooled field coils, the hydraulic motor sizing and direct coupling, the low-impedance removable field coils, and the hydrostatic bearing design.

Impact Of Secondary-Primary Pumps Operating Sequence On The Electrical Power Supply System

International Nuclear Information System (INIS)

Suwoto; Rusdiyanto; Kiswanto

2001-01-01

The operating procedure of the reactor cooling system has decided that the primary cooling pump should be operated before secondary cooling pump as known primary-secondary pumps operating sequence. This decision is based on consideration that starting current of the primary pump is higher than secondary pump. Therefore, the primary-secondary pumps operating sequence can avoid the power supply system failure. However, this operating procedure has to take a consequence that in case of primary pump failure, the shutdown time period of the reaktor to be longer caused to re operate the primary pump has required that the running secondary pump should be shutted off. To solve this problem, an impact analysis of the secondary-primary pumps operating sequence on the electric power supply system was carried out to identify the revision possibility of the cooling pump operating procedure. The analysis by discussion of the measuring results of the secondary and primary pump starting current related to another electrical loads has been measured. From discussion it can be concluded that secondary-primary pumps operating sequence has no impact to failure in electric power supply system

Ultracapacitor-Based Uninterrupted Power Supply System

Science.gov (United States)

Eichenberg, Dennis J.

2011-01-01

The ultracapacitor-based uninterrupted power supply (UPS) system enhances system reliability; reduces life-of-system, maintenance, and downtime costs; and greatly reduces environmental impact when compared to conventional UPS energy storage systems. This design provides power when required and absorbs power when required to smooth the system load and also has excellent low-temperature performance. The UPS used during hardware tests at Glenn is an efficient, compact, maintenance-free, rack-mount, pure sine-wave inverter unit. The UPS provides a continuous output power up to 1,700 W with a surge rating of 1,870 W for up to one minute at a nominal output voltage of 115 VAC. The ultracapacitor energy storage system tested in conjunction with the UPS is rated at 5.8 F. This is a bank of ten symmetric ultracapacitor modules. Each module is actively balanced using a linear voltage balancing technique in which the cell-to-cell leakage is dependent upon the imbalance of the individual cells. The ultracapacitors are charged by a DC power supply, which can provide up to 300 VDC at 4 A. A constant-voltage, constant-current power supply was selected for this application. The long life of ultracapacitors greatly enhances system reliability, which is significant in critical applications such as medical power systems and space power systems. The energy storage system can usually last longer than the application, given its 20-year life span. This means that the ultracapacitors will probably never need to be replaced and disposed of, whereas batteries require frequent replacement and disposal. The charge-discharge efficiency of rechargeable batteries is approximately 50 percent, and after some hundreds of charges and discharges, they must be replaced. The charge-discharge efficiency of ultracapacitors exceeds 90 percent, and can accept more than a million charges and discharges. Thus, there is a significant energy savings through the efficiency improvement, and there is far less

Thermal Impact Analysis of Circulating Current in High Power Modular Online Uninterruptible Power Supplies Application

DEFF Research Database (Denmark)

Zhang, Chi; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

2017-01-01

In modular uninterruptible power supplies (UPSs), several DC/AC modules are required to work in parallel. This structure allows the system to be more reliable and flexible. These DC/AC modules share the same DC bus and AC critical bus. Module differences, such as filter inductor, filter capacitor......, control parameters, and so on, will make it possible for the potential zero sequence current to flow among the modules. This undesired type of circulating current will bring extra losses to the power semiconductor devices in the system, which should be paid special attention in high power application...... scenarios. In this paper, plug’n’play modules and cycle control are discussed and validated through experimental results. Moreover, potential zero sequence circulating current impact on power semiconductor devices thermal performance is also analyzed in this paper....

Design of the klystron filament power supply control system for EAST LHCD

Energy Technology Data Exchange (ETDEWEB)

Wu, Zege; Wang, Mao; Hu, Huaichuan; Ma, Wendong; Zhou, Taian; Zhou, Faxin; Liu, Fukun; Shan, Jiafang [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

2016-09-15

A filament is a critical component of the klystron used to heat the cathode. There are totally 44 klystrons in experimental advanced superconducting tokamak (EAST) lower hybrid current drive (LHCD) systems. All klystron filaments are powered by AC power suppliers through isolated transformers. In order to achieve better klystron preheat, a klystron filament power supply control system is designed to obtain the automatic control of all filament power suppliers. Klystron filament current is measured by PLC and the interlock between filament current and klystron high voltage system is also implemented. This design has already been deployed in two LHCD systems and proves feasible completely.

Customer system efficiency improvement assessment: Supply curves for transmission and distribution conservation options

Energy Technology Data Exchange (ETDEWEB)

Tepel, R.C.; Callaway, J.W.; De Steese, J.G.

1987-11-01

This report documents the results of Task 6 in the Customer System Efficiency Improvement (CSEI) Assessment Project. A principal objective of this project is to assess the potential for energy conservation in the transmission and distribution (TandD) systems of electric utilities in the BPA service area. The scope of this assessment covers BPA customers in the Pacific Northwest region and all non-federal TandD systems, including those that currently place no load on the BPA system. Supply curves were developed to describe the conservation resource potentially available from TandD-system efficiency improvements. These supply curves relate the levelized cost of upgrading existing equipment to the estimated amount of energy saved. Stated in this form, the resource represented by TandD loss reductions can be compared with other conservation options and regional electrical generation resources to determine the most cost-effective method of supplying power to the Pacific Northwest. The development of the supply curves required data acquisition and methodology development that are also described in this report. 11 refs., 11 figs., 16 tabs.

The role of enterprise systems in supply chain networks: a taxonomy of supply chain strategies

DEFF Research Database (Denmark)

Møller, Charles

2006-01-01

in the supply chain and to choose the right supply chain strategy. The work is based on a comprehensive study of the Supply Chain Management (SCM) and Enterprise Resource Planning (ERP) literature and the study suggests that there is an emerging new research potential for Enterprise Systems (ES) in the supply......This paper proposes a taxonomy for supply chain integration strategies. The taxonomy is based on the contingencies of supply chain network coupling and the Extended Enterprise Systems (EES) architecture in the supply chain. The purpose of this model is to map the portfolio of relations...

Capacitor current feedback for output filter damping in switched-mode magnet power supplies

International Nuclear Information System (INIS)

Paven Kumar, M.R.; Kim, J.M.S.

1994-01-01

In magnet power supplies for a particle accelerator system, a second-order low-pass filter is used to reduce the output current ripple content within specifications. The output filter must be properly damped in order to avoid any large amplification at the resonant frequency and large transient responses of voltages and currents at the step change of the line voltage. Conventionally, a series combination of resistance and capacitance is added in parallel with the filter capacitor to provide the required damping. This approach, however, requires a large dc-blocking capacitor which has to be several times larger than the filter capacitor. In this paper, a filter damping technique using capacitor current feedback is presented. The basic concept of the capacitor current feedback is established using a linear model of the converter involved, and then a sampled-data model of the converter is used to analyze the filter damping technique. The filter damping effect of the capacitor current feedback is verified experimentally

Resonance power supplies for large accelerator

International Nuclear Information System (INIS)

Karady, G.; Schneider, E.J.

1993-01-01

The resonance power supply has been proposed as an efficient power supply for a future 6 GB, keon producing accelerator. This report presents a detailed analysis of the circuit operation. Based on these analyses each component is designed, one line diagram is developed, component requirements are determined and a detailed cost estimate is prepared. The major components of the system are: the magnet power supply, high voltage by-pass thyristor switch, with l0kA repetitive interruption capability, capacitor banks, capacitor bank thyristor switch, and an energy make up device. The most important components are the bypass thyristor switch and the energy injection device. The bypass thyristor switch is designed to turn on and interrupt to 10 kA dc current with a recovery voltage of 20kV and repetition frequency of 3 Hz. The switch consists of a large array of series and parallel connected thyristors and gate turn off (GTO) devices. The make up energy device is designed to replace the circuit energy losses. A capacitor bank is charged with constant current and discharged during the acceleration period. One of the advantages of the developed circuit is that it can be supplied directly from the local power network. In order to prove the validity of the assumptions, a scaled down model circuit was thoroughly tested. These tests proved that the engineering design of critical components is correct and this resonant power supply can be properly controlled by an inventer/rectifier connected in series with the magnet and by the make up energy device. This finding reduces the system cost

Virtual resistance-based control strategy for DC link regeneration protection and current sharing in uninterruptible power supply

DEFF Research Database (Denmark)

Lu, Jinghang; Guan, Yajuan; Savaghebi, Mehdi

2017-01-01

To address the DC link voltage regeneration issue in parallel Uninterruptible Power Supply (UPS) system, a DC link voltage protection (DCVP) method through online virtual resistance regulation is proposed. The proposed control strategy is able to protect the DC link from overvoltage that may...... trigger the protection mechanism of the UPS system. Moreover, a current sharing control strategy by regulating the virtual resistance is proposed to address the circulating current caused by the active power feeding. Finally, the feasibility of the proposed method is verified by experimental results from...

Environmental assessment of current and future Swiss electricity supply options

International Nuclear Information System (INIS)

Bauer, Christian; Heck, Thomas; Hirschberg, Stefan; Dones, Roberto

2008-01-01

Options for near future electricity supply are currently one of the main topics in the Swiss energy policy debate. Contrary to the total energy demand per capita the trend of rising electricity demand per capita is still visible. This paper presents a comparative environmental assessment of a broad portfolio of current and future electricity generation technologies including nuclear, fossil, and renewable power plants with their associated energy chains. The evaluation, based on Life Cycle Assessment (LCA), is carried out quantifying ten different environmental indicators, grouped in the categories greenhouse gas emissions, consumption of resources, waste, and impact on ecosystems. Hydropower shows minimal environmental impacts for all indicators; for other systems, the picture is diverse. The comparison of non-aggregated indicators allows preliminary conclusions about the environmental performance of the assessed systems. Establishing ranking of technologies calls for aggregating the indicators, which can be done by weighting of the indicators based on individual or stakeholder group preferences, either within a Multi-Criteria Decision Analysis (MCDA) framework or with Life Cycle Impact Assessment (LCIA) methods. Calculating total costs of electricity by adding external costs due to impacts on human health and ecosystems to the electricity production costs poses another option for ranking of technologies. (authors)

ECONOMIC PRINCIPLES FOR SELECTION OF OPTIMUM POWER-SUPPLY SYSTEM DEVELOPMENT IN BELARUS

Directory of Open Access Journals (Sweden)

L. P. Padalko

2008-01-01

Full Text Available The paper considers main directions of the technological development of the Belarusian power-supply system. Comparative analysis of the economic efficiency of thermal power station modernization on the basis of steam- and gas technology, nuclear technology development and simple renovation of the worn-out generating capacities of thermal power stations has been carried out in the paper. Selection of the priority direction pertaining to optimization of industrial structure of the Belarusian power-supply system has been made on the basis of the presented minimum-specific cost criterion. The paper reveals that in the medium-term period the most optimum development of the Belarusian electrical power engineering is a technological  modernization  due to predicted  changes in natural gas and nuclear fuel costs. The modernization presupposes construction of topping plants in addition to the existing steam- and turbine equipment at thermal power stations. 

Statistical mechanical characteristics of slip-ring induction motors when direct current braking

Energy Technology Data Exchange (ETDEWEB)

Kedzior, W; Muchorowski, J; Pienkowski, K

1980-09-01

This paper evaluates methods of braking high capacity belt conveyors used in brown coal surface mines in Poland. Complications associated with belt conveyor braking, particularly when a conveyor moves down a slope, are analyzed. A method of calculating mechanical characteristics of wound-rotor induction motors during direct current braking taking into account saturation of magnetic circuit is presented. Characteristics of the SZUr motor with 630 kW power, used in brown coal mining, are also given. Analyses show that motor operation can be efficiently braked in two ways: 1. by changing additional resistance in rotor circuit (e.g. using thyristor controller); 2. by changing intensity of electric current supplied to stator winding (e.g. using a rectifier). (3 refs.) (In Polish)

High-voltage direct-current circuit breakers

International Nuclear Information System (INIS)

Yoshioka, Y.; Hirasawa, K.

1991-01-01

This paper reports that in 1954 the first high-voltage direct-current (HVDC) transmission system was put into operation between Gotland and the mainland of Sweden. Its system voltage and capacity were 100 kV and 20 MW, respectively. Since then many HVDC transmission systems have been planned, constructed, or commissioned in more than 30 places worldwide, and their total capacity is close to 40 GW. Most systems commissioned to date are two-terminal schemes, and HVDC breakers are not yet used in the high-potential main circuit of those systems, because the system is expected to perform well using only converter/inverter control even at a fault stage of the transmission line. However, even in a two-terminal scheme there are not a few merits in using an HVDC breaker when the system has two parallel transmission lines, that is, when it is a double-circuit system

A three-port direct current converter

DEFF Research Database (Denmark)

2016-01-01

circuit comprises a connection between the at least one input direct current source and the at least one storage battery, the primary side circuit configured for operating as a buck converter; a second magnetic component serially coupled to the first single magnetic component, wherein the first and second...... magnetic components are configured to perform a voltage step-up, wherein the secondary side circuit comprises a connection between the at least one storage battery and at least one load, the secondary side configured for operating as a tapped boost converter; wherein the three-port direct current converter......The three-port direct current converter comprising: at least one input direct current source; at least one storage battery; a primary side circuit; a secondary side circuit; a first single magnetic component shared by the primary side circuit and the secondary side circuit, wherein the primary side...

MEASUREMENT AND ANALYSIS OF TRANSMISSION LOSSES IN THE SUPPLY SYSTEM OF ELECTRIFIED TRANSPORT

Directory of Open Access Journals (Sweden)

Mikołaj Bartłomiejczyk

2016-11-01

Full Text Available The issue of electric energy saving in public transport is currently becoming a key area of interest, a fact connected with both an increase in society’s environmental awareness and a rise in the prices of fuel and electricity. Electricity can be saved by reducing transmission losses in the supply system. The article presents a method of measurement and analysis of transmission losses in the supply system of electrified public transport on the example of trolleybus transport in Gdynia and Lublin in Poland.

Current and Future Research Directions in Requirements Engineering

Science.gov (United States)

Cheng, Betty H. C.; Atlee, Joanne M.

In this paper, we review current requirements engineering (RE) research and identify future research directions suggested by emerging software needs. First, we overview the state of the art in RE research. The research is considered with respect to technologies developed to address specific requirements tasks, such as elicitation, modeling, and analysis. Such a review enables us to identify mature areas of research, as well as areas that warrant further investigation. Next, we review several strategies for performing and extending RE research results, to help delineate the scope of future research directions. Finally, we highlight what we consider to be the “hot” current and future research topics, which aim to address RE needs for emerging systems of the future.

Current economic downturn and supply chain : The significance of demand and inventory smoothing

NARCIS (Netherlands)

Cannella, S.; Ashayeri, J.; Miranda, P.A.; Bruccoleri, M.

2014-01-01

The aim of this article is to analyse and quantify the effects of demand and inventory smoothing into supply-chain performance, facing the extreme volatility and impetuous alteration of the market produced by the current economic recession. To do so, we model a traditional serial three-stage supply

Abort kicker power supply systems at Fermilab

International Nuclear Information System (INIS)

Krafczyk, G.; Dugan, G.; Harrison, M.; Koepke, K.; Tilles, E.

1985-06-01

Over the past several years, Fermilab has been operating with a single turn proton abort system in both the superconducting Tevatron and the conventional Main Ring. The abort kicker power supply for this system discharges a lumped capacitance into the inductive magnet load, causing the beam to enter the abort channel. The characteristics of this current waveform are defined by the requirements of the machine operation. The standard fixed target running mode calls for 12 booster batches of beam which leaves a rotating gap in the beams of approx.1.8 μs. The current waveform is required to rise to 90% of I/sub max/ in this time to avoid beam loss from partially deflected beam. Aperture limitations in both the accelerator and the abort channel demand that the current in the magnets stays above this 90% I/sub max/ for the 21 μs needed to ensure all the beam has left the machine. The 25 mm displacement needed to cleanly enter the abort channel at 1 TeV corresponds to a maximum current in each of the 4 modules of approx.20 kA. Similar constraints are needed for the Main Ring and Tevatron antiproton abort systems. A unique feature of this design is the high voltage, high current diode assembly used to clip the recharge of the capacitor bank. This allows the current to decay slowly with the L/R time constant of the magnet and diode series combination. Special attention is given to the diode characteristics needed for this passive switching element. Operational experience and proposed upgrades are given for the two operational systems. 2 refs., 4 figs., 1 tab

Abort kicker power supply systems at Fermilab

International Nuclear Information System (INIS)

Krafczyk, G.; Dugan, G.; Harrison, M.; Koepke, K.; Tilles, E.

1985-01-01

Over the past several years, Fermilab has been operating with a single turn proton abort system in both the superconducting Tevatron and the conventional Main Ring. The abort kicker power supply for this system discharges a lumped capacitance into the inductive magnet load, causing the beam to enter the abort channel. The characteristics of this current waveform are defined by the requirements of the machine operation. The standard fixed target running mode calls for 12 booster batches of beam which leaves a rotating gap in the beam of about1.8 μs. The current waveform is required to rise to 90% of I /SUB max/ in this time to avoid beam loss from partially deflected beam. Aperture limitations in both the accelerator and the abort channel demand that the current in the magnets stays above this 90% I for the 21 μs needed to ensure all the beam has /SUP max/ left the machine. The 25 mm displacement needed to cleanly enter the abort channel at 1 TeV corresponds to a maximum current in each of the 4 modules of about20 kA. Similar constraints are needed for the Main Ring and Tevatron antiproton abort systems. A unique feature of this design is the high voltage, high current diode assembly used to clip the recharge of the capacitor bank. This allows the current to decay slowly with the L/R time constant of the magnet and diode series combination. Special attention will be given to the diode characteristics needed for this passive switching element. Operational experience and proposed upgrades will be given for the two operational systems

120-keV beam direct conversion system for TFTR injectors

International Nuclear Information System (INIS)

Hamilton, G.W.

1976-01-01

Several practical motivations exist for the development of beam direct conversion systems that are compatible with the injection systems of large experiments such as the Tokamak Fusion Test Reactor (TFTR). We present a preliminary design in which we analyze the most acute problems involved in scaling up existing designs and apparatus to fulfill TFTR requirements. Some of the questions addressed are the requirements for electron suppression, gas pumping, compactness, and power densities. A new idea is presented that allows for the handling of higher beam power. The gross savings in the capital cost of injector power supplies for the TFTR will be about $7.2 million, but the net savings will be somewhat less than this. This preliminary design has not yet revealed fundamental limitations with respect to the development of beam energy-recovery systems operating at high levels of current, voltage, and power densities

An approach for high voltage power supply system for HCAL of LHCb experiment

International Nuclear Information System (INIS)

Cimpean, A.; Dumitru, D.; Kluger, A.; Magureanu, C.; Tarta, D.; Coca, C.; Orlandea, M.; Popescu, S.

2003-01-01

The main aim of the calorimeter system of the LHCb (Large Hadron Collider Beauty) experiment dedicated to precision measurements of CP violation and rare phenomena is to provide identification of the electrons, hadrons and photons, for the level-0 trigger and offline analysis with measurements of position and energy. The system consists in a scintillator pad/preshower (SPD/PS) detector, an electromagnetic calorimeter (ECAL) and a hadron calorimeter (HCAL), all the sub-detectors having a similar technology with scintillating tiles as active material and being read out via wavelength-shifting fibers and with an identical readout electronics for ECAL and HCAL and similar electronics for the PS. During 1997-1999 a computer controlled High Voltage (HV) distribution scheme was developed by Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH) group and used to supply the PMTs of half HCAL prototype during the beam tests (1998-2000). This scheme consisted of three parts: 1) a control box which includes low voltage power supply, the RS232 interface to a PC and three modules of high voltage power supply; 2) two types of multichannel HV distributors with an individual voltage setting; 3) a software package to control all settings and refresh them periodically. Based on the acquired experience, a new design for a High Voltage Power Supply (HVPS) which satisfies the LHCb requirements has been developed for PMTs of the hadron calorimeter. The demands of this system are simplicity and low cost. This HVPS with multiple outputs (HV for photocathode and D1 - D4 dynodes) is destined to supply, with the same high voltage, groups of PMTs sorted by similar characteristics as gain and sensitivity. Because of the high rates (∼ 40 MHz) supported by PMTs, booster voltage sources are necessary to supply current for the last 4 dynodes. The box has 5 HV power supplies for photocathodes and the last 4 dynodes, each HV power supply being followed by a 4 channel

Current regulators for I/SUP 2/L circuits to be operated from low-voltage power supplies

DEFF Research Database (Denmark)

Bruun, Erik; Hansen, Ole

1980-01-01

A new bandgap current reference is described which can be used to control the injector current of I/SUP 2/L circuits for supply voltages down to about 1 V. For small currents the total injector current is obtained as a mirror of the reference current. For large injector currents the current control......, but well controlled temperature coefficient is desired. It is shown how a temperature stable ring oscillator with I/SUP 2/L gates can be constructed by tailoring the temperature dependence of the supply current appropriately....

How current are EURATOM provisions on nuclear supply and ownership in view of the European Union's enlargement?

International Nuclear Information System (INIS)

Bouquet, A.

2001-01-01

This contribution is mainly based on two papers presented at nuclear law conferences in 1998 and 2001, respectively setting out the special provisions governing supplies of nuclear fuels to the European Union (Chapter 6 of the Treaty establishing the European Atomic Energy Community, hereinafter referred to as the 'Euratom Treaty') and the right of ownership of the Euratom Community (Chapter 8 of the Euratom Treaty). These special Treaty provisions cannot be compared to anything observed in other legal systems. Hence, with their introduction into the legal systems of the new European Union member states, the question arises as to how current these provisions are and how they have been implemented in practice. Two of the fundamental objectives of the Euratom Treaty most relevant in this field are to ensure that all users in the Community receive a regular and equitable supply of ores and nuclear fuels (Article 2d Euratom) and to exercise the Community's right of ownership with respect to special fissile materials (Article 2f Euratom). Furthermore, the objectives of ensuring the establishment of the basic installations necessary for the development of nuclear energy in the Community (Article 2c Euratom), of safeguarding that material is not diverted from its intended use (Article 2e Euratom), of establishing a common market (Article 2g Euratom) and of maintaining external relations (Article 2h Euratom) can be relevant to nuclear trade and to the Supply Agency's action. The Treaty's philosophy with regard to supply and ownership is the result of a delicate compromise between public authority interventionism and a more free market approach. The interventionism resulted in a monopolistic system of supplies (exclusive right to conclude contracts, right of option, public authority ownership), whereas the free market approach brought about the commercial organisation of the entity responsible for the implementation of supply provisions (separate legal entity, market

Research tokamak system with multi-mode discharges using inverter power supply

International Nuclear Information System (INIS)

Kojima, Hiroki; Kobayashi, Masahiro; Takagi, Makoto; Takamura, Shuichi; Tashiro, Kenji

1999-01-01

In Current Sustaining Tokamak in Nagoya university (CSTN)-IV research tokamak system using a compact 40kHz pulse width modulation (PWM) inverter power supply, which is controlled through LabVIEW program, we construct a new tokamak discharge system with multi-mode including a stable alternating current discharge and a high-repetition high-duty one. These discharge modes can be operated continuously for as long as 60sec. The continuous discharge with long duration is able to simulate the important physical and chemical processes of long time discharges in fusion devices, in which the heat load to the wall and the particle balance in the plasma-wall system are crucial topics in order to realize a long pulse fusion reactor, like ITER. Employing ergodic divertor (ED) is one of tools to control the particle balance and the heat load to the wall. In addition, we installed another inverter power supply to generate a rotating magnetic perturbation for dynamic ergodic divertor (DED) with the appropriate measurement system so that we may carry out experiments on heat and particle control with DED at long time operation. (author)

Conceptual adsorption system of cooling and heating supplied by solar energy

Directory of Open Access Journals (Sweden)

Turski Michał

2016-06-01

Full Text Available This paper presents the possibility of reducing the demand for nonrenewable primary energy for buildings using a new conceptual adsorption system of cooling and heating supplied by solar energy. Moreover, the aim of this study is to shorten the payback time of investment in the standard adsorption cooling system through its integration with the heating system. Research has been carried out for an energy-efficient medium-sized single-family building with a floor area of 140 m2 and a heat load of 4.2 kW and cold load of 4.41 kW. It has been shown that the use of an adsorption system of cooling and heating supplied by solar energy decreased the demand for nonrenewable primary energy by about 66% compared to the standard building that meets the current requirements.

Direct-current cathodic vacuum arc system with magnetic-field mechanism for plasma stabilization.

Science.gov (United States)

Zhang, H-S; Komvopoulos, K

2008-07-01

Filtered cathodic vacuum arc (FCVA) deposition is characterized by plasma beam directionality, plasma energy adjustment via substrate biasing, macroparticle filtering, and independent substrate temperature control. Between the two modes of FCVA deposition, namely, direct current (dc) and pulsed arc, the dc mode yields higher deposition rates than the pulsed mode. However, maintaining the dc arc discharge is challenging because of its inherent plasma instabilities. A system generating a special configuration of magnetic field that stabilizes the dc arc discharge during film deposition is presented. This magnetic field is also part of the out-of-plane magnetic filter used to focus the plasma beam and prevent macroparticle film contamination. The efficiency of the plasma-stabilizing magnetic-field mechanism is demonstrated by the deposition of amorphous carbon (a-C) films exhibiting significantly high hardness and tetrahedral carbon hybridization (sp3) contents higher than 70%. Such high-quality films cannot be produced by dc arc deposition without the plasma-stabilizing mechanism presented in this study.

Direct-current cathodic vacuum arc system with magnetic-field mechanism for plasma stabilization

International Nuclear Information System (INIS)

Zhang, H.-S.; Komvopoulos, K.

2008-01-01

Filtered cathodic vacuum arc (FCVA) deposition is characterized by plasma beam directionality, plasma energy adjustment via substrate biasing, macroparticle filtering, and independent substrate temperature control. Between the two modes of FCVA deposition, namely, direct current (dc) and pulsed arc, the dc mode yields higher deposition rates than the pulsed mode. However, maintaining the dc arc discharge is challenging because of its inherent plasma instabilities. A system generating a special configuration of magnetic field that stabilizes the dc arc discharge during film deposition is presented. This magnetic field is also part of the out-of-plane magnetic filter used to focus the plasma beam and prevent macroparticle film contamination. The efficiency of the plasma-stabilizing magnetic-field mechanism is demonstrated by the deposition of amorphous carbon (a-C) films exhibiting significantly high hardness and tetrahedral carbon hybridization (sp 3 ) contents higher than 70%. Such high-quality films cannot be produced by dc arc deposition without the plasma-stabilizing mechanism presented in this study

NSTX Protection And Interlock Systems For Coil And Powers Supply Systems

International Nuclear Information System (INIS)

Zhao, X.; Ramakrishnan, S.; Lawson, J.; Neumeyer, C.; Marsala, R.; Schneider, H.

2009-01-01

NSTX at Princeton Plasma Physics Laboratory (PPPL) requires sophisticated plasma positioning control system for stable plasma operation. TF magnetic coils and PF magnetic coils provide electromagnetic fields to position and shape the plasma vertically and horizontally respectively. NSTX utilizes twenty six coil power supplies to establish and initiate electromagnetic fields through the coil system for plasma control. A power protection and interlock system is utilized to detect power system faults and protect the TF coils and PF coils against excessive electromechanical forces, overheating, and over current. Upon detecting any fault condition the power system is restricted, and it is either prevented from initializing or suppressed to de-energize coil power during pulsing. Power fault status is immediately reported to the computer system. This paper describes the design and operation of NSTX's protection and interlocking system and possible future expansion.

Bidirectional interactions between neuronal and hemodynamic responses to transcranial direct current stimulation (tDCS: challenges for brain-state dependent tDCS

Directory of Open Access Journals (Sweden)

Anirban eDutta

2015-08-01

Full Text Available Transcranial direct current stimulation (tDCS has been shown to modulate cortical neural activity. During neural activity, the electric currents from excitable membranes of brain tissue superimpose in the extracellular medium and generate a potential at scalp, which is referred as the electroencephalogram (EEG. Respective neural activity (energy demand has been shown to be closely related, spatially and temporally, to cerebral blood flow (CBF that supplies glucose (energy supply via neurovascular coupling. The hemodynamic response can be captured by near-infrared spectroscopy (NIRS, which enables continuous monitoring of cerebral oxygenation and blood volume. This neurovascular coupling phenomenon led to the concept of neurovascular unit (NVU that consists of the endothelium, glia, neurons, pericytes, and the basal lamina. Here, recent works suggest NVU as an integrated system working in concert using feedback mechanisms to enable proper brain homeostasis and function where the challenge remains in capturing these mostly nonlinear spatiotemporal interactions within NVU during tDCS. Therefore, we propose EEG-NIRS-based whole-head monitoring of tDCS-induced neuronal and hemodynamic alterations for brain-state dependent tDCS.

System Dynamics Modeling for Supply Chain Information Sharing

Science.gov (United States)

Feng, Yang

In this paper, we try to use the method of system dynamics to model supply chain information sharing. Firstly, we determine the model boundaries, establish system dynamics model of supply chain before information sharing, analyze the model's simulation results under different changed parameters and suggest improvement proposal. Then, we establish system dynamics model of supply chain information sharing and make comparison and analysis on the two model's simulation results, to show the importance of information sharing in supply chain management. We wish that all these simulations would provide scientific supports for enterprise decision-making.

Influence of current pulse shape on directly modulated system performance in metro area optical networks

Science.gov (United States)

Campos, Carmina del Rio; Horche, Paloma R.; Martin-Minguez, Alfredo

2011-03-01

Due to the fact that a metro network market is very cost sensitive, direct modulated schemes appear attractive. In this paper a CWDM (Coarse Wavelength Division Multiplexing) system is studied in detail by means of an Optical Communication System Design Software; a detailed study of the modulated current shape (exponential, sine and gaussian) for 2.5 Gb/s CWDM Metropolitan Area Networks is performed to evaluate its tolerance to linear impairments such as signal-to-noise-ratio degradation and dispersion. Point-to-point links are investigated and optimum design parameters are obtained. Through extensive sets of simulation results, it is shown that some of these shape pulses are more tolerant to dispersion when compared with conventional gaussian shape pulses. In order to achieve a low Bit Error Rate (BER), different types of optical transmitters are considered including strongly adiabatic and transient chirp dominated Directly Modulated Lasers (DMLs). We have used fibers with different dispersion characteristics, showing that the system performance depends, strongly, on the chosen DML-fiber couple.

Multi-level access control in the data pipeline of the international supply chain system

NARCIS (Netherlands)

Pruksasri, P.; Berg, J. van den; Hofman, W.; Daskapan, S.

2013-01-01

The Seamless Integrated Data Pipeline system was proposed to the European Union in order to overcome the information quality shortcomings of the current international supply chain information exchange systems. Next to identification and authorization of stakeholders, secure access control needs to

[Drug supply chain safety in hospitals: current data and experience of the Grenoble university hospital].

Science.gov (United States)

Bedouch, P; Baudrant, M; Detavernier, M; Rey, C; Brudieu, E; Foroni, L; Allenet, B; Calop, J

2009-01-01

Drug supply chain safety has become a priority for public health which implies a collective process. This process associates all health professionals including the pharmacist who plays a major role. The objective of this present paper is to describe the several approaches proven effective in the reduction of drug-related problem in hospital, illustrated by the Grenoble University Hospital experience. The pharmacist gets involved first in the general strategy of hospital drug supply chain, second by his direct implication in clinical activities. The general strategy of drug supply chain combines risk management, coordination of the Pharmacy and Therapeutics Committee, selection and purchase of drugs and organisation of drug supply chain. Computer management of drug supply chain is a major evolution. Nominative drug delivering has to be a prior objective and its implementation modalities have to be defined: centralized or decentralized in wards, manual or automated. Also, new technologies allow the automation of overall drug distribution from central pharmacy and the implementation of automated drug dispensing systems into wards. The development of centralised drug preparation allows a safe compounding of high risk drugs, like cytotoxic drugs. The pharmacist should develop his clinical activities with patients and other health care professionals in order to optimise clinical decisions (medication review, drug order analysis) and patients follow-up (therapeutic monitoring, patient education, discharge consultation).

Superconducting toroidal field coil power supply and protection system for NET

International Nuclear Information System (INIS)

Hicks, J.B.

1986-01-01

A power supply and quench protection system is proposed in which alternate coils are connected in series to produce two separate circuits, each with 8 coils. Both circuits are provided with power supplies comprising rectifier transformers and thyristor equipped Graetz bridges, which are operated at maximum forward voltage (125 V) to charge the coils to 24 kA, 17.75 GJ in ≅ 2 hours and are fully inverted for scheduled discharges. Pulsed firing of the thyristors allows the same power supplies to be used to maintain the currents against resistive losses, without increasing the reactive power consumption or harmonic current generation. Rapid discharges are initiated by opening d.c. circuit breakers to introduce discharge resistors between the coils of each circuit. The maximum possible value of peak voltage-to-ground is then limited to 2.25 times the discharge voltage applied to each coil. A 5 kV discharge voltage allows the coils to be discharged with a time constant of 18.5 s, which is sufficiently rapid to limit the quench ''hot spot'' temperature to 68 K. The coil connections impose sufficient symmetry on the coil current distribution to ensure that no out-of-plane forces are produced on the coils. Even if one circuit breaker fails to interrupt, the variation of coil currents is sufficiently small that the resulting symmetric variation of radial centring forces is acceptable

250 kV 6 mA compact Cockcroft-Walton high-voltage power supply

Energy Technology Data Exchange (ETDEWEB)

Ma, Zhan-Wen; Su, Xiao-Dong; Wei, Zhen; Huang, Zhi-Wu; Miao, Tian-You; Su, Tong-Ling [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Lu, Xiao-Long; Wang, Jun-Run; Yao, Ze-En, E-mail: zeyao@lzu.edu.cn [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Engineering Research Center for Neutron Application, Ministry of Education, Lanzhou University, Lanzhou 730000 (China)

2016-08-15

A compact power supply system for a compact neutron generator has been developed. A 4-stage symmetrical Cockcroft-Walton circuit is adopted to produce 250 kV direct current high-voltage. A 2-stage 280 kV isolation transformer system is used to drive the ion source power supply. For a compact structure, safety, and reliability during the operation, the Cockcroft-Walton circuit and the isolation transformer system are enclosed in an epoxy vessel containing the transformer oil whose size is about ∅350 mm × 766 mm. Test results indicate that the maximum output voltage of the power supply is 282 kV, and the stability of the output voltage is better than 0.63% when the high voltage power supply is operated at 250 kV, 6.9 mA with the input voltage varying ±10%.

Installation design of pump motor control systems for supplied of the RSG-GAS secondary raw water cooling system

International Nuclear Information System (INIS)

Kiswanto; Teguh Sulistyo; M-Taufik

2013-01-01

It has designed already of an installation of the pump motor control system for supplied of raw water to fulfil the RSG-GAS secondary cooling system. The installation design of this plant is used to supply electrical energy from PLN and 3 phase generator to operate the pump motor embedded multilevel type, capacity, Q = 30 m 3 /h; electric power, PN = 4 kW; voltage, 380V/3-/50Hz, and Y connections that can be operated manually or automatically by using the automatic transfer switch. The results obtained recapitulation total load of 4 kW, the magnitude of the nominal current of 9.5 A; kind of safety and capacity are used NFB 16 A, use of this type of cable to the control panel is PLN NYY 6 mm 2 diameter maximum current capacity of 25 A cable and use the control panel to the pump motor cable type NYY 4 mm 2 diameter maximum current capacity of 20 A. The design of the pump motor control system installation is ready to be implemented. (author)

Hybrid renewable energy system application for electricity and heat supply of a residential building

Directory of Open Access Journals (Sweden)

Nakomčić-Smaragdakis Branka B.

2016-01-01

Full Text Available Renewable and distributed energy systems could provide a solution to the burning issue of reliable and clean supply of energy, having in mind current state and future predictions for population growth and fossil fuel scarcity. Hybrid renewable energy systems are novelty in Serbia and warrant further detailed research. The aim of this paper is to analyze the application of renewable energy sources(RES for electricity and heat supply of a typical household in Serbia, as well as the cost-effectiveness of the proposed system. The influence of feed-in tariff change on the value of the investment is analyzed. Small, grid-connected hybrid system (for energy supply of a standard household, consisting of geothermal heat pump for heating/cooling, solar photovoltaic panels and small wind turbine for power supply is analyzed as a case study. System analysis was conducted with the help of RETScreen software. Results of techno-economics analysis have shown that investing in geothermal heat pump and photovoltaic panels is cost-effective, while that is not the case with small wind turbine.

Modeling sustainability in renewable energy supply chain systems

Science.gov (United States)

Xie, Fei

This dissertation aims at modeling sustainability of renewable fuel supply chain systems against emerging challenges. In particular, the dissertation focuses on the biofuel supply chain system design, and manages to develop advanced modeling framework and corresponding solution methods in tackling challenges in sustaining biofuel supply chain systems. These challenges include: (1) to integrate "environmental thinking" into the long-term biofuel supply chain planning; (2) to adopt multimodal transportation to mitigate seasonality in biofuel supply chain operations; (3) to provide strategies in hedging against uncertainty from conversion technology; and (4) to develop methodologies in long-term sequential planning of the biofuel supply chain under uncertainties. All models are mixed integer programs, which also involves multi-objective programming method and two-stage/multistage stochastic programming methods. In particular for the long-term sequential planning under uncertainties, to reduce the computational challenges due to the exponential expansion of the scenario tree, I also developed efficient ND-Max method which is more efficient than CPLEX and Nested Decomposition method. Through result analysis of four independent studies, it is found that the proposed modeling frameworks can effectively improve the economic performance, enhance environmental benefits and reduce risks due to systems uncertainties for the biofuel supply chain systems.

Directed Motivational Currents: Using vision to create effective motivational pathways

Directory of Open Access Journals (Sweden)

Christine Muir

2013-10-01

Full Text Available Vision, that is, the mental representation of the sensory experience of a future goal state (involving imagination and imagery, is currently at the forefront of motivational innovation, and in recent years it has been seen increasingly more often in the motivational tool kit of practicing language teachers. Theories such as Dörnyei’s L2 motivational self system have explored the power that creating effective visions can harness (see, e.g., Dörnyei & Kubanyiova, 2014 and when viewed in conjunction with other current research avenues, such as future time perspective and dynamic systems theory, vision offers exciting potential. A Directed Motivational Current is a new motivational construct that we suggest is capable of integrating many current theoretical strands with vision: It can be described as a motivational drive which energises long-term, sustained behaviour (such as language learning, and through placing vision and goals as critical central components within this construct, it offers real and practical motivational potential. In this conceptual paper, we first discuss current understandings of vision and of Directed Motivational Currents, and then analyse how they may be optimally integrated and employed to create effective motivational pathways in language learning environments.

The simulation of control system for the KEK main ring power supply, 1

International Nuclear Information System (INIS)

Sato, Hikaru; Shintomi, Takakazu; Kubo, Tadashi; Masuda, Masayoshi; Nakano, Michio.

1975-09-01

The simulation of control system for the KEK main ring power supply is performed. The inductance of the magnet is assumed to be linear against to the current. The results of the simulations are described. (auth.)

Analysis of trends in the development of cities' heat supply systems

Science.gov (United States)

Stennikov, V. A.; Mednikova, E. E.

2016-09-01

New challenges—including the modern urban development policy, formation of the market of energy efficient technologies and different types of equipment of a broad power capacity range, tightening requirements to reliability, quality, and economic accessibility of heat supply—enhance the competitiveness of decentralized heat supply. In addition, its spontaneous growth and not always reasonable implementation lead to unjustified expenses, low efficiency, and ecological inconsistency. This proves the relevance of solving the problems of dividing an urban territory into zones of centralized heating (CH) and decentralized heating (DCH) along with their planning and justification, as well as determining a reasonable level of heat supply centralization and concentration of heat sources' power capacity. Solving these problems using the suggested method will allow optimizing the application areas for various types of heat supply and heat sources, justifying the degree of heat power capacity concentration and the extent of the systems as early as at the phase of a detailed urban planning project and then refining them during the design of urban heat supply systems. This will dramatically improve the reasonability of the decisions made and will simplify the procedure of their implementation. For criteria of limiting the extent (radius) of heat supply systems and defining their type, we suggest using standard values—the density of heat load per unit length of the pipeline and per unit area of urban territory. Standard values must be differentiated across the territory of Russia taking into account regional climatic and economic conditions and unique characteristics of heat supply development in cities and towns. The present article continues and develops the statements made in the previous articles created within the framework of the Theory of Hydraulic Circuits and takes into account the current situation and emerging trends in heat supply.

Energy costs and Portland water supply system

Energy Technology Data Exchange (ETDEWEB)

Elliott, W.M.; Hawley, R.P.

1981-10-01

The changing role of electrical energy on the Portland, Oregon, municipal-water-supply system is presented. Portland's actions in energy conservation include improved operating procedures, pump modifications, and modifications to the water system to eliminate pumping. Portland is implementing a small hydroelectric project at existing water-supply dams to produce an additional source of power for the area. Special precautions in construction and operation are necessary to protect the high quality of the water supply. 2 references, 7 figures.

Systems thinking benefits in supply change management:an illustration of the viable systems model in a supply chain

OpenAIRE

Chronéer, Diana; Mirijamdotter, Anita

2009-01-01

Existing product development models are solely an organisational matter. They do not take into consideration the whole supply chain and its different actors. We investigate in this paper how Supply Chain Management (SCM) and Viable System Model (VSM) can support and create an effective use of information in product development and hence identify critical linkages in the supply chain. The aim is to introduce VSM as a framework that enable an analysis of company's supply chains and visualize vi...

Four giga joule flywheel motor-generator for JT-60 toroidal field coil power supply system

International Nuclear Information System (INIS)

Matsukawa, T.; Kanke, M.; Shimada, R.; Yoshida, Y.; Yamashita, K.; Nakayama, T.

1986-01-01

A fusion test reactor often needs motor-generators as a power source in order to reduce disturbances to utility lines. The toroidal field coil power supply system of JT-60 also adopted a motor-generator for this purpose. The motor-generator started operation in April, 1985 at Japan Atomic Energy Research Institute together with the whole system. The motor-generator has several special features both electrically and mechanically. One electrical feature is that it is used as a pulse source of large current and power for periodic short-time duty. A mechanical feature is that a large flywheel is directly coupled to the motor-generator shaft and operated intermittently and at high speed. Therefore detailed investigations were carried out concerning constitution, characteristics as well as the coordination with the system performance. This paper describes the outlines of the flywheel motor-generator and discusses several topics

JT-60SA power supply system

International Nuclear Information System (INIS)

Coletti, A.; Baulaigue, O.; Cara, P.; Coletti, R.; Ferro, A.; Gaio, E.; Matsukawa, M.; Novello, L.; Santinelli, M.; Shimada, K.; Starace, F.; Terakado, T.; Yamauchi, K.

2011-01-01

The paper describes the main features of the Superconducting Magnets Power Supply to generate the toroidal and poloidal magnetic fields in JT-60SA tokamak, with special regard to coil current regulation mode and magnets protection.

Maximising water supply system yield subject to multiple reliability ...

African Journals Online (AJOL)

Maximising water supply system yield subject to multiple reliability constraints via simulation-optimisation. ... Water supply systems have to satisfy different demands that each require various levels of reliability ... and monthly operating rules that maximise the yield of a water supply system subject to ... HOW TO USE AJOL.

Novel robotic systems and future directions

Directory of Open Access Journals (Sweden)

Ki Don Chang

2018-01-01

Full Text Available Robot-assistance is increasingly used in surgical practice. We performed a nonsystematic literature review using PubMed/MEDLINE and Google for robotic surgical systems and compiled information on their current status. We also used this information to predict future about the direction of robotic systems based on various robotic systems currently being developed. Currently, various modifications are being made in the consoles, robotic arms, cameras, handles and instruments, and other specific functions (haptic feedback and eye tracking that make up the robotic surgery system. In addition, research for automated surgery is actively being carried out. The development of future robots will be directed to decrease the number of incisions and improve precision. With the advent of artificial intelligence, a more practical form of robotic surgery system can be introduced and will ultimately lead to the development of automated robotic surgery system.

Common bus multinode sensor system

International Nuclear Information System (INIS)

Kelly, T.F.; Naviasky, E.H.; Evans, W.P.; Jefferies, D.W.; Smith, J.R.

1988-01-01

This patent describes a nuclear power plant including a common bus multinode sensor system for sensors in the nuclear power plant, each sensor producing a sensor signal. The system consists of: a power supply providing power; a communication cable coupled to the power supply; plural remote sensor units coupled between the cable and one or more sensors, and comprising: a direct current power supply, connected to the cable and converting the power on the cable into direct current; an analog-to-digital converter connected to the direct current power supply; an oscillator reference; a filter; and an integrated circuit sensor interface connected to the direct current power supply, the analog-to-digital converter, the oscillator crystal and the filter, the interface comprising: a counter receiving a frequency designation word from external to the interface; a phase-frequency comparator connected to the counter; an oscillator connected to the oscillator reference; a timing counter connected to the oscillator, the phase/frequency comparator and the analog-to-digital converter; an analog multiplexer connectable to the sensors and the analog-to-digital converter, and connected to the timing counter; a shift register operatively connected to the timing counter and the analog-to-digital converter; an encoder connected to the shift register and connectable to the filter; and a voltage controlled oscillator connected to the filter and the cable

Modeling of biomass-to-energy supply chain operations: Applications, challenges and research directions

International Nuclear Information System (INIS)

Mafakheri, Fereshteh; Nasiri, Fuzhan

2014-01-01

Reducing dependency on fossil fuels and mitigating their environmental impacts are among the most promising aspects of utilizing renewable energy sources. The availability of various biomass resources has made it an appealing source of renewable energy. Given the variability of supply and sources of biomass, supply chains play an important role in the efficient provisioning of biomass resources for energy production. This paper provides a comprehensive review and classification of the excising literature in modeling of biomass supply chain operations while linking them to the wider strategic challenges and issues with the design, planning and management of biomass supply chains. On that basis, we will present an analysis of the existing gaps and the potential future directions for research in modeling of biomass supply chain operations. - Highlights: • An extensive review of biomass supply chain operations management models presented in the literature is provided. • The models are classified in line with biomass supply chain activities from harvesting to conversion. • The issues surrounding biomass supply chains are investigated manifesting the need to novel modeling approaches. • Our gap analysis has identified a number of existing shortcomings and opportunities for future research

Virtual Inertia: Current Trends and Future Directions

Directory of Open Access Journals (Sweden)

Ujjwol Tamrakar

2017-06-01

Full Text Available The modern power system is progressing from a synchronous machine-based system towards an inverter-dominated system, with large-scale penetration of renewable energy sources (RESs like wind and photovoltaics. RES units today represent a major share of the generation, and the traditional approach of integrating them as grid following units can lead to frequency instability. Many researchers have pointed towards using inverters with virtual inertia control algorithms so that they appear as synchronous generators to the grid, maintaining and enhancing system stability. This paper presents a literature review of the current state-of-the-art of virtual inertia implementation techniques, and explores potential research directions and challenges. The major virtual inertia topologies are compared and classified. Through literature review and simulations of some selected topologies it has been shown that similar inertial response can be achieved by relating the parameters of these topologies through time constants and inertia constants, although the exact frequency dynamics may vary slightly. The suitability of a topology depends on system control architecture and desired level of detail in replication of the dynamics of synchronous generators. A discussion on the challenges and research directions points out several research needs, especially for systems level integration of virtual inertia systems.

The Challenge of Providing Safe Water with an Intermittently Supplied Piped Water Distribution System

Science.gov (United States)

Kumpel, E.; Nelson, K. L.

2012-12-01

An increasing number of urban residents in low- and middle-income countries have access to piped water; however, this water is often not available continuously. 84% of reporting utilities in low-income countries provide piped water for fewer than 24 hours per day (van den Berg and Danilenko, 2010), while no major city in India has continuous piped water supply. Intermittent water supply leaves pipes vulnerable to contamination and forces households to store water or rely on alternative unsafe sources, posing a health threat to consumers. In these systems, pipes are empty for long periods of time and experience low or negative pressure even when water is being supplied, leaving them susceptible to intrusion from sewage, soil, or groundwater. Households with a non-continuous supply must collect and store water, presenting more opportunities for recontamination. Upgrading to a continuous water supply, while an obvious solution to these challenges, is currently out of reach for many resource-constrained utilities. Despite its widespread prevalence, there are few data on the mechanisms causing contamination in an intermittent supply and the frequency with which it occurs. Understanding the impact of intermittent operation on water quality can lead to strategies to improve access to safe piped water for the millions of people currently served by these systems. We collected over 100 hours of continuous measurements of pressure and physico-chemical water quality indicators and tested over 1,000 grab samples for indicator bacteria over 14 months throughout the distribution system in Hubli-Dharwad, India. This data set is used to explore and explain the mechanisms influencing water quality when piped water is provided for a few hours every 3-5 days. These data indicate that contamination occurs along the distribution system as water travels from the treatment plant to reservoirs and through intermittently supplied pipes to household storage containers, while real

Condensing and water supplying systems in an atomic power plant

International Nuclear Information System (INIS)

Shinmura, Akira.

1975-01-01

Object: To reduce heat loss and eliminate accumulation of drain in water supplying and heating units in an atomic power plant by providing a direct contact type drain cooler between a gland-exhauster vapor condenser and a condensing and de-salting means, the drain from each water supplying and heating unit being collected in said cooler for heating the condensed water. Structure: Condensed water from a condenser is fed by a low pressure condensing pump through an air ejector and gland-exhauster vapor condenser to the direct-contact type drain cooler and is condensed in each water supply heater. Next, it is heated by drain fed through a drain level adjuster valve and an orifice and then forced by a medium pressure condenser pump into the condensing and de-salting means. It is then supplied by a high pressure condensing pump into the successive water supply heater. (Kamimura, M.)

Systems approach to design of power supply to mines

Energy Technology Data Exchange (ETDEWEB)

Shul' ga, Yu I; Voloshko, A V

1986-09-01

Optimization of power supplies to underground coal mines in the USSR is evaluated. Systems analysis of power systems is discussed. Power system of a coal mine is treated as an element of the branch power system which forms a subsystem of the local and national power system. Design of a system for computerized control of power supplies to underground coal mines is evaluated. Elements of the system, control equipment, types of information stored and processed by the system as well as economic efficiency of using computerized control for power supply in underground mining are discussed. Recommendations for computer-aided design of power systems and use of computerized control systems for power supply in underground coal mining in the USSR are made.

Field Trial on a Rack-mounted DC Power Supply System with 80-Ah Lithium-ion Batteries

Science.gov (United States)

Matsushima, Toshio

Using an industrial lithium-ion battery that has higher energy density than conventional valve-regulated lead-acid batteries, a rack-mounted DC-power-supply system was assembled and tested at a base transceiver station (BTS) offering actual services. A nominal output voltage and maximum output current of the system is 53.5V and 20A, respectively. An 80-Ah lithium-ion battery composed of 13 cells connected in series was applied in the system and maintained in a floating charge method. The DC-power-supply system was installed in a 19-inch power rack in the telecommunications equipment box at BTS. The characteristics of the 80Ah lithium-ion battery, specifications of the DC-power-supply system and field-test results were shown in this paper.

Enhanced motor learning with bilateral transcranial direct current stimulation: Impact of polarity or current flow direction?

Science.gov (United States)

Naros, Georgios; Geyer, Marc; Koch, Susanne; Mayr, Lena; Ellinger, Tabea; Grimm, Florian; Gharabaghi, Alireza

2016-04-01

Bilateral transcranial direct current stimulation (TDCS) is superior to unilateral TDCS when targeting motor learning. This effect could be related to either the current flow direction or additive polarity-specific effects on each hemisphere. This sham-controlled randomized study included fifty right-handed healthy subjects in a parallel-group design who performed an exoskeleton-based motor task of the proximal left arm on three consecutive days. Prior to training, we applied either sham, right anodal (a-TDCS), left cathodal (c-TDCS), concurrent a-TDCS and c-TDCS with two independent current sources and return electrodes (double source (ds)-TDCS) or classical bilateral stimulation (bi-TDCS). Motor performance improved over time for both unilateral (a-TDCS, c-TDCS) and bilateral (bi-TDCS, ds-TDCS) TDCS montages. However, only the two bilateral paradigms led to an improvement of the final motor performance at the end of the training period as compared to the sham condition. There was no difference between the two bilateral stimulation conditions (bi-TDCS, ds-TDCS). Bilateral TDCS is more effective than unilateral stimulation due to its polarity-specific effects on each hemisphere rather than due to its current flow direction. This study is the first systematic evaluation of stimulation polarity and current flow direction of bi-hemispheric motor cortex TDCS on motor learning of proximal upper limb muscles. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Tuning magnet power supply

International Nuclear Information System (INIS)

Han, B.M.; Karady, G.G.; Thiessen, H.A.

1989-01-01

The particles in a Rapid Cycling Accelerator are accelerated by rf cavities, which are tuned by dc biased ferrite cores. The tuning is achieved by the regulation of bias current, which is produced by a power supply. The tuning magnet power supply utilizes a bridge circuit, supplied by a three phase rectifier. During the rise of the current, when the particles are accelerated, the current is controlled with precision by the bridge which operates a power amplifier. During the fall of the current, the bridge operates in a switching mode and recovers the energy stored in the ferrites. The recovered energy is stored in a capacitor bank. The bridge circuit is built with 150 power transistors. The drive, protection and control circuit were designed and built from commercial component. The system will be used for a rf cavity experiment in Los Alamos and will serve as a prototype tuning power supply for future accelerators. 1 ref., 7 figs

Development of an integrated medical supply information system

Science.gov (United States)

Xu, Eric; Wermus, Marek; Blythe Bauman, Deborah

2011-08-01

The integrated medical supply inventory control system introduced in this study is a hybrid system that is shaped by the nature of medical supply, usage and storage capacity limitations of health care facilities. The system links demand, service provided at the clinic, health care service provider's information, inventory storage data and decision support tools into an integrated information system. ABC analysis method, economic order quantity model, two-bin method and safety stock concept are applied as decision support models to tackle inventory management issues at health care facilities. In the decision support module, each medical item and storage location has been scrutinised to determine the best-fit inventory control policy. The pilot case study demonstrates that the integrated medical supply information system holds several advantages for inventory managers, since it entails benefits of deploying enterprise information systems to manage medical supply and better patient services.

30 CFR 36.27 - Fuel-supply system.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Fuel-supply system. 36.27 Section 36.27 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF... Construction and Design Requirements § 36.27 Fuel-supply system. (a) Fuel tank. (1) The fuel tank shall not...

Design of all-optical, hot-electron current-direction-switching device based on geometrical asymmetry.

Science.gov (United States)

Kumarasinghe, Chathurangi S; Premaratne, Malin; Gunapala, Sarath D; Agrawal, Govind P

2016-02-18

We propose a nano-scale current-direction-switching device(CDSD) that operates based on the novel phenomenon of geometrical asymmetry between two hot-electron generating plasmonic nanostructures. The proposed device is easy to fabricate and economical to develop compared to most other existing designs. It also has the ability to function without external wiring in nano or molecular circuitry since it is powered and controlled optically. We consider a such CDSD made of two dissimilar nanorods separated by a thin but finite potential barrier and theoretically derive the frequency-dependent electron/current flow rate. Our analysis takes in to account the quantum dynamics of electrons inside the nanorods under a periodic optical perturbation that are confined by nanorod boundaries, modelled as finite cylindrical potential wells. The influence of design parameters, such as geometric difference between the two nanorods, their volumes and the barrier width on quality parameters such as frequency-sensitivity of the current flow direction, magnitude of the current flow, positive to negative current ratio, and the energy conversion efficiency is discussed by considering a device made of Ag/TiO2/Ag. Theoretical insight and design guidelines presented here are useful for customizing our proposed CDSD for applications such as self-powered logic gates, power supplies, and sensors.

Vulnerability Assessment of Water Supply Systems: Status, Gaps and Opportunities

Science.gov (United States)

Wheater, H. S.

2015-12-01

Conventional frameworks for assessing the impacts of climate change on water resource systems use cascades of climate and hydrological models to provide 'top-down' projections of future water availability, but these are subject to high uncertainty and are model and scenario-specific. Hence there has been recent interest in 'bottom-up' frameworks, which aim to evaluate system vulnerability to change in the context of possible future climate and/or hydrological conditions. Such vulnerability assessments are generic, and can be combined with updated information from top-down assessments as they become available. While some vulnerability methods use hydrological models to estimate water availability, fully bottom-up schemes have recently been proposed that directly map system vulnerability as a function of feasible changes in water supply characteristics. These use stochastic algorithms, based on reconstruction or reshuffling methods, by which multiple water supply realizations can be generated under feasible ranges of change in water supply conditions. The paper reports recent successes, and points to areas of future improvement. Advances in stochastic modeling and optimization can address some technical limitations in flow reconstruction, while various data mining and system identification techniques can provide possibilities to better condition realizations for consistency with top-down scenarios. Finally, we show that probabilistic and Bayesian frameworks together can provide a potential basis to combine information obtained from fully bottom-up analyses with projections available from climate and/or hydrological models in a fully integrated risk assessment framework for deep uncertainty.

An Annotated Bibliography of High-Voltage Direct-Current Transmission and Flexible AC Transmission (FACTS) Devices, 1991-1993.

Energy Technology Data Exchange (ETDEWEB)

Litzenberger, Wayne; Lava, Val

1994-08-01

References are contained for HVDC systems, converter stations and components, overhead transmission lines, cable transmission, system design and operations, simulation of high voltage direct current systems, high-voltage direct current installations, and flexible AC transmission system (FACTS).

Supply chain planning classification

Science.gov (United States)

Hvolby, Hans-Henrik; Trienekens, Jacques; Bonde, Hans

2001-10-01

Industry experience a need to shift in focus from internal production planning towards planning in the supply network. In this respect customer oriented thinking becomes almost a common good amongst companies in the supply network. An increase in the use of information technology is needed to enable companies to better tune their production planning with customers and suppliers. Information technology opportunities and supply chain planning systems facilitate companies to monitor and control their supplier network. In spite if these developments, most links in today's supply chains make individual plans, because the real demand information is not available throughout the chain. The current systems and processes of the supply chains are not designed to meet the requirements now placed upon them. For long term relationships with suppliers and customers, an integrated decision-making process is needed in order to obtain a satisfactory result for all parties. Especially when customized production and short lead-time is in focus. An effective value chain makes inventory available and visible among the value chain members, minimizes response time and optimizes total inventory value held throughout the chain. In this paper a supply chain planning classification grid is presented based current manufacturing classifications and supply chain planning initiatives.

Electrical railway transportation systems

CERN Document Server

Brenna, Morris; Zaninelli, Dario

2018-01-01

Allows the reader to deepen their understanding of various technologies for both fixed power supply installations of railway systems and for railway rolling stock. This book explores the electric railway systems that play a crucial role in the mitigation of congestion and pollution caused by road traffic. It is divided into two parts: the first covering fixed power supply systems, and the second concerning the systems for railway rolling stock. In particular, after a historical introduction to the framework of technological solutions in current use, the authors investigate electrification systems for the power supply of rail vehicles, trams, and subways. Electrical Railway Transportation Systems explores the direct current systems used throughout the world for urban and suburban transport, which are also used in various countries for regional transport. It provides a study of alternating current systems, whether for power supply frequency or for special railway frequency, that are used around the world for ...

Power supply and stabilization of the supply system on board using decentralized voltage rectifiers

Energy Technology Data Exchange (ETDEWEB)

Grueb, W; Wegerer, K

1987-04-01

The functionally redundant power supply system of the Transrapid 06 II maglev train is described; it comprises four independent, battery-buffered networks and 30 linear generators per train section. Voltage rectifiers adapt the velocity- and load-dependent linear generator voltage to the 440 V d.c. networks and assure dynamic stabilisation as well as buffer battery loading. The result is a high-reliability power supply system on board with optimum utilisation of the power supplied by the linear generators while the train is running.

A design of cascade control system and adaptive load compensator for battery/ultracapacitor hybrid energy storage-based direct current microgrid

International Nuclear Information System (INIS)

Pavković, Danijel; Lobrović, Mihael; Hrgetić, Mario; Komljenović, Ante

2016-01-01

Highlights: • Battery/ultracapacitor storage is considered for a direct-current microgrid. • Microgrid voltage cascade control system with load compensator is designed. • Current references are allocated so that ultracapacitor takes on transient loads. • Adaptive Kalman filter-based estimator is used for indirect load compensation. • Control strategy has been verified on a downscaled hardware-in-the-loop setup. - Abstract: A control system design based on an actively-controlled battery/ultracapacitor hybrid energy storage system suitable for direct current microgrid energy management purposes is presented in this paper. The proposed cascade control system arrangement is based on the superimposed proportional–integral voltage controller designed according to Damping Optimum criterion and a zero-pole canceling feed-forward load compensator aimed at voltage excursion suppression under variable load conditions. The superimposed controller commands the inner battery and ultracapacitor current control loops through a dynamic current reference distribution scheme, wherein the ultracapacitor takes on the highly-dynamic (transient) current demands, and the battery covers for steady-state loads. In order to avoid deep discharges of the ultracapacitor module, it is equipped with an auxiliary state-of-charge controller. Finally, for those applications where load is not measured, an adaptive Kalman filter-based load compensator is proposed and tested. The presented control strategy has been implemented on the low-cost industrial controller unit, and its effectiveness has been verified by means of simulations and experiments for the cases of abrupt load changes and quasi-stochastic load profiles using a downscaled battery/ultracapacitor hardware-in-the-loop experimental setup.

Monitoring of heavy metals in selected Water Supply Systems in Poland, in relation to current regulations

Science.gov (United States)

Szuster-Janiaczyk, Agnieszka; Zeuschner, Piotr; Noga, Paweł; Skrzypczak, Marta

2018-02-01

The study presents an analysis of water quality monitoring in terms of the content of heavy metals, which is conducted in three independent water supply systems in Poland. The analysis showed that the monitoring of heavy metals isn't reliable - both the quantity of tested water samples and the location of the monitoring points are the problem. The analysis of changes in water quality from raw water to tap water was possible only for one of the analysed systems and indicate a gradual deterioration of water quality, although still within acceptable limits of legal regulations.

Life-cycle energy impacts for adapting an urban water supply system to droughts.

Science.gov (United States)

Lam, Ka Leung; Stokes-Draut, Jennifer R; Horvath, Arpad; Lane, Joe L; Kenway, Steven J; Lant, Paul A

2017-12-15

In recent years, cities in some water stressed regions have explored alternative water sources such as seawater desalination and potable water recycling in spite of concerns over increasing energy consumption. In this study, we evaluate the current and future life-cycle energy impacts of four alternative water supply strategies introduced during a decade-long drought in South East Queensland (SEQ), Australia. These strategies were: seawater desalination, indirect potable water recycling, network integration, and rainwater tanks. Our work highlights the energy burden of alternative water supply strategies which added approximately 24% life-cycle energy use to the existing supply system (with surface water sources) in SEQ even for a current post-drought low utilisation status. Over half of this additional life-cycle energy use was from the centralised alternative supply strategies. Rainwater tanks contributed an estimated 3% to regional water supply, but added over 10% life-cycle energy use to the existing system. In the future scenario analysis, we compare the life-cycle energy use between "Normal", "Dry", "High water demand" and "Design capacity" scenarios. In the "Normal" scenario, a long-term low utilisation of the desalination system and the water recycling system has greatly reduced the energy burden of these centralised strategies to only 13%. In contrast, higher utilisation in the unlikely "Dry" and "Design capacity" scenarios add 86% and 140% to life-cycle energy use of the existing system respectively. In the "High water demand" scenario, a 20% increase in per capita water use over 20 years "consumes" more energy than is used by the four alternative strategies in the "Normal" scenario. This research provides insight for developing more realistic long-term scenarios to evaluate and compare life-cycle energy impacts of drought-adaptation infrastructure and regional decentralised water sources. Scenario building for life-cycle assessments of water supply

Hydropower recovery in water supply systems: Models and case study

International Nuclear Information System (INIS)

Vilanova, Mateus Ricardo Nogueira; Balestieri, José Antônio Perrella

2014-01-01

Highlights: • We present hydropower recovery models for water supply systems. • Hydropower recovery potential in water supply systems is highly variable. • The case studied could make the supply systems self-sufficient in terms of energy. • Hydropower recovery can reduce GHGs emissions and generate carbon credits. - Abstract: The energy efficiency of water supply systems can be increased through the recovery of hydraulic energy implicit to the volumes of water transported in various stages of the supply process, which can be converted into electricity through hydroelectric recovery systems. Such a process allows the use of a clean energy source that is usually neglected in water supplies, reducing its dependence on energy from the local network and the system’s operation costs. This article evaluates the possibilities and benefits of the use of water supply facilities, structures and equipment for hydraulic energy recovery, addressing several applicable hydroelectric models. A real case study was developed in Brazil to illustrate the technical, economic and environmental aspects of hydropower recovery in water supply systems

Brainstem tumors: Current management and future directions

Directory of Open Access Journals (Sweden)

Pablo F Recinos

2012-01-01

Full Text Available Tumors arising in the brainstem comprise 10-20% of all pediatric central nervous system (CNS tumors and account for a small percentage in adults. The prognosis for these tumors was considered uniformly poor prior to the era of modern neuroimaging and the location was fraught with disaster being considered a ′no man′s land′ for neurosurgeons. Following the introduction of advanced imaging modalities and neurophysiological monitoring, striking progress has occurred in the management of these lesions. Brainstem tumors are presently classified based on their anatomic location, focality, and histopathology. This article reviews the current classification of brainstem tumors, current management options, and future directions in the treatment for these rare tumors.

IMPROVING MODEL OF CHANNEL AIRBORN ELECTRICAL POWER SYSTEM OF ALTERNATING CURRENT

Directory of Open Access Journals (Sweden)

Yu. P. Artemenko

2015-01-01

Full Text Available This article is devoted to math modeling of channel of alternating current airborne electrical power-supply system. Mathematical modeling of generator, voltage regulator, constant speed drive is considered.

Modification of the Japanese first nuclear ship reactor for a regional energy supply system

International Nuclear Information System (INIS)

Sato, K.; Shimazu, Y.; Narabayashi, T.; Tsuji, M.

2008-01-01

Nuclear Ship Mutsu was developed as the first experimental nuclear ship of Japan. It has several advantages as a prototype for regional energy supply system. Considering the attractive advantages of the Mutsu reactor, we investigated the feasibility of development of a small regional energy system by adopting the Mutsu reactor as a starting model. The system could supply with not only electricity but also heat. Heat could be used for hot-water supply, a heating system of a house, melting snow and so on, especially for those in northern part of Japan. The system should satisfy the requirements for GEN IV systems and the current regulations. From this point of view, the modification of the reactor was initiated by taking into improvements and technology of the state of arts to fulfill the requirements such as (1) Longer core life without refueling, (2) Reactivity adjustment for load change without control rods or soluble boron, (3) Simpler operations for load changes and (4) Ultimate safety with sufficient passive capability. Currently it is assumed to use basic standard 17x17 fuel assembly design for WH type PWRs. Nuclear design calculations are carried out by 'SRAC 2002 ', which has been developed in Japan Atomic Energy Agency. Several problems have not been solved yet, but we confirmed the proposed core has about 10 years life time. So the proposed core has a possibility to be used for a small regional energy system. (authors)

Analog fault diagnosis based on ramping power supply current signature clusters

NARCIS (Netherlands)

Somayajula, S.A.S.; Sanchez-Sinencio, E.; Pineda de Gyvez, J.

1996-01-01

Measurement of power supply currents was found to be very useful for testing CMOS IC's because of its potential to detect a large class of manufacturing defects. However, this technique was used mainly for fault detection and was confined to digital circuits. In this paper, we present a suited

Primary power supply of repetitive pulsed intense current accelerator charged by capacitance of energy store

International Nuclear Information System (INIS)

Chen Jun; Yang Jianhua; Shu Ting; Zhang Jiande; Zhou Xiang; Wen Jianchun

2008-01-01

The primary power supply of repetitive pulsed intense current accelerator charged by capacitance of energy store is studied. The principle of primary power supply circuit and its time diagram of switches are presented. The circuit is analyzed and some expressions are got, especially, the usable voltage scope of capacitance of energy store, and the correlation between the parameters of circuit and time delay, which is between the turn-on of the charging circuit of capacitance of energy store and the circuit of recuperation. The time delay of 256 x 256 lookup table is made with the instruction of theory and the simulation of the actual parameters of circuits. The table is used by the control program to control the repetitive operating of the actual pulsed intense current accelerator. Finally, some conclusions of the primary power supply of repetitive pulsed intense current accelerator charged by capacitance of energy store are got. (authors)

High-current heavy-ion accelerator system and its application to material modification

International Nuclear Information System (INIS)

Kishimoto, Naoki; Takeda, Yoshihiko; Lee, C.G.; Umeda, Naoki; Okubo, Nariaki; Iwamoto, Eiji

2001-01-01

A high-current heavy-ion accelerator system has been developed to realize intense particle fluxes for material modification. The facility of a tandem accelerator attained 1 mA-class ion current both for negative low-energy ions and positive high-energy ions. The negative ion source of the key device is of the plasma-sputter type, equipped with mutli-cusp magnets and Cs supply. The intense negative ions are either directly used for material irradiation at 60 keV or further accelerated up to 6 MeV after charge transformation. Application of negative ions, which alleviates surface charging, enables us to conduct low-energy high-current irradiation on insulating substrates. Since positive ions above the MeV range are irrelevant for Coulomb repulsion, the facility as a whole meets the needs of high-current irradiation onto insulators over a wide energy range. Application of high flux ions provides technological merits not only for efficient implantation but also for essentially different material kinetics, which may become an important tool of material modification. Other advantages of the system are co-irradiation by intense laser and in-situ detection of kinetic processes. For examples of material modifications, we present nanoparticle fabrication in insulators, and synergistic phenomena by co-irradiation due to ions and photons. (author)

Promotion of direct marketing and supply on demand of electric power from renewable energy sources. Final report; Foerderung der Direktvermarktung und der bedarfsgerechten Einspeisung von Strom aus Erneuerbaren Energien. Endbericht

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-06-23

The study investigates the promotion of direct marketing and supply on demand of electric power from renewable energy sources in Germany. the study shows that renewable energy sources are a good option for facing the challenges of the future. However, the potential is often left unused because of a lack of incentives in the current pricing system. To solve this problem, the Federal Ministry of the Environment, Nature Conservation and Nuclear Safety authorized two studies that are to enable or improve the utilization of the integration potentials of the renewable energy sources. Two model proposals based on these studies are presented here. The model proposing a bonus for combined-cycle power plants is to ensure supply on demand of electric power from renewables with the aid of integrated power storage systems. However, it is found that this model will not generate significant effects for power supply on demand. The second model proposes financial incentives; it will work well for renewable power supply systems that can be controlled, e.g. bioenergy, run-of-river power plants with power storage, and biogas plants. On the other hand, supply-dependent technologies like wind power, photovoltaic power, run-of-river power plants without power storage, and geothermal power plants with very low variable cost, the goal is not fully reached. In contrast to the first model, the market incentives model will enhance the integration of renewable energy sources in the competitive market by largely eliminating market risks. (orig./RHM)

An Overview of Hybrid Water Supply Systems in the Context of Urban Water Management: Challenges and Opportunities

Directory of Open Access Journals (Sweden)

Mukta Sapkota

2014-12-01

Full Text Available This paper presents a critical review of the physical impacts of decentralized water supply systems on existing centralized water infrastructures. This paper highlights the combination of centralized and decentralized systems, which is referred to as hybrid water supply systems. The system is hypothesized to generate more sustainable and resilient urban water systems. The basic concept is to use decentralized water supply options such as rainwater tanks, storm water harvesting and localized wastewater treatment and reuse in combination with centralized systems. Currently the impact of hybrid water supply technologies on the operational performance of the downstream infrastructure and existing treatment processes is yet to be known. The paper identifies a number of significant research gaps related to interactions between centralized and decentralized urban water services. It indicates that an improved understanding of the interaction between these systems is expected to provide a better integration of hybrid systems by improved sewerage and drainage design, as well as facilitate operation and maintenance planning. The paper also highlights the need for a framework to better understand the interaction between different components of hybrid water supply systems.

Comparison of series regulated neutral beam accel supplies with shunt regulated accel supplies

International Nuclear Information System (INIS)

Baker, W.; Smith, B.H.

1976-01-01

This study was undertaken to get a direct comparison between comparable series and shunt regulated power supplies. It is intended that the two supplies will be strictly equivalent with the same safety factors in the design of each type and the cost estimates made on the same basis. The series regulated power supply is simply a scaled up version of the 2XIIB Accel Supplies. Each supply provides 150 kV, 65 ampere, 500 ms pulse output such as will be used on the TFTR sources. The shunt regulated power supply uses high reactance transformers to provide the series impedance for the shunt regulator. The most significant difference in the performance of the two types of power supplies is that the shunt regulated supply has a minimum interrupt period of 16 ms, whereas the series regulated supply can have about 0.5 ms. Even this difference can be eliminated with a commutator circuit such as is being developed in Berkeley for the 150 kV, 20 ampere system. The 16 ms period is probably not a very serious limitation because it still permits up to 31 interrupts per 500 ms pulse. The shunt regulated system appears to be about 37 percent less expensive than the series system

A Review of the Wood Pellet Value Chain, Modern Value/Supply Chain Management Approaches, and Value/Supply Chain Models

Directory of Open Access Journals (Sweden)

Natalie M. Hughes

2014-01-01

Full Text Available We reviewed 153 peer-reviewed sources to provide identification of modern supply chain management techniques and exploration of supply chain modeling, to offer decision support to managers. Ultimately, the review is intended to assist member-companies of supply chains, mainly producers, improve their current management approaches, by directing them to studies that may be suitable for direct application to their supply chains and value chains for improved efficiency and profitability. We found that information on supply chain management and modeling techniques in general is available. However, few Canadian-based published studies exist regarding a demand-driven modeling approach to value/supply chain management for wood pellet production. Only three papers were found specifically on wood pellet value chain analysis. We propose that more studies should be carried out on the value chain of wood pellet manufacturing, as well as demand-driven management and modeling approaches with improved demand forecasting methods.

Association between medication supplies and healthcare costs in older adults from an urban healthcare system.

Science.gov (United States)

Stroupe, K T; Murray, M D; Stump, T E; Callahan, C M

2000-07-01

The amount of medication dispensed to older adults for the treatment of chronic disease must be balanced carefully. Insufficient medication supplies lead to inadequate treatment of chronic disease, whereas excessive supplies represent wasted resources and the potential for toxicity. We used an electronic medical record system to determine the distribution of medications supplied to older urban adults and to examine the correlations of these distributions with healthcare costs and use. A cross-sectional study using data acquired over 3 years (1994-1996). A tax-supported urban public healthcare system consisting of a 300-bed hospital, an emergency department, and a network of community-based ambulatory care centers. Patients were >60 years of age and had at least one prescription refill and at least two ambulatory visits or one hospitalization during the 3-year period. Focusing on 12 major categories of drugs used to treat chronic diseases, we determined the amounts and direct costs of these medications dispensed to older adult patients. Amounts of medications that were needed by patients to medicate themselves adequately were compared with the medication supply actually dispensed considering all sources of care (primary, emergency, and inpatient). We calculated the excess drug costs attributable to oversupply of medication (>120% of the amount needed) and the drug cost reduction caused by undersupply of medication (120% of the supply needed. The total direct cost of targeted medications for 3 years was $1.96 million or, on average, $654,000 annually. During the 3-year period, patients receiving >120% of their needed medications had excess direct medication costs of $279,084 or $144 per patient, whereas patients receiving <80% of drugs needed had reduced medication costs of $423,438 or $634 per patient. Multivariable analyses revealed that both under- and over-supplies of medication were associated with a greater likelihood of emergency department visits and hospital

Design of arc power supply for neutral beam injection system based on super capacitor energy storage

International Nuclear Information System (INIS)

Yang Puqiong; Xuan Weimin; Cao Jianyong; Li Qing; Liu Xiaolong

2015-01-01

The arc power supply is one of the most important equipment for neutral beam injection system. The stability of arc discharge and the quality of ion beam extraction were determined by its performance. For improving stability of the arc discharge, reducing the power network capacity and decreasing impulse on power network, the topology of the arc power supply applied the structure of DC/DC converter based on technology of super capacitor energy storage and switching power supply. Several IGBT power modules are operated in parallel, and it can improve the arc power supply's operating frequency and dynamic response. A filter circuit and a current fast transferring circuit were designed based on a detailed analysis on working process of the arc power sup- ply. According to the requirements and parameters of the arc power supply, and the current response of RL first order circuit, the minimum filter inductances were accurately calculated. Finally, using the model and Matlab, the performance of the arc power supply was simulated and verified, and it meets the design requirement. (authors)

Energy, economy, and environment analysis and optimization on manufacturing plant energy supply system

International Nuclear Information System (INIS)

Feng, Lujia; Mears, Laine; Beaufort, Cleveland; Schulte, Joerg

2016-01-01

Highlights: • Single objective and multicriteria optimization approaches are proposed. • Objectives of energy, economy, and environment are proved conflicting. • 3-input-5-output energy supply system of an automotive plant is studied. - Abstract: Increasing attention has recently been drawn to energy consumption in manufacturing plants. Facing the challenges from reducing emissions coupled with rising raw material prices and energy costs, manufacturers are trying to balance the energy usage strategy among the total energy consumption, economy, and environment, which can be self-conflicting at times. In this paper, energy systems in manufacturing environments are reviewed, and the current status of onsite energy system and renewable energy usage are discussed. Single objective and multicriteria optimization approaches are effectively formulated for making the best use of energy delivered to the production processes. Energy supply operation suggestions based on the optimization results are obtained. Finally, an example from an automotive assembly manufacturer is described to demonstrate the energy usage in the current manufacturing plants and how the optimization approaches can be applied to satisfy the energy management objectives. According to the optimization results, in an energy oriented operation, it takes 35% more in monetary cost; while in an economy oriented operation, it takes 17% more in megawatt hour energy supply and tends to rely more on the inexpensive renewable energy.

Conceptual study on HTGR-IS hydrogen supply system using organic hydrides

International Nuclear Information System (INIS)

Terada, Atsuhiko; Noguchi, Hiroki; Takegami, Hiroaki; Kamiji, Yu; Inagaki, Yoshiyuki

2012-02-01

We have proposed a hydrogen supply-chain system, which is a storage/supply system of large amount of hydrogen produced by HTGR-IS hydrogen production system. The organic chemical hydride method is one of the candidate techniques in the system for hydrogen storage and transportation. In this study, properties of organic hydrides and conventional hydrogen storage/supply system were surveyed to make use of the conceptual design of the hydrogen supply system using an organic hydrides method with VHTR-IS hydrogen production process (hydrogen production: 85,400 Nm 3 /h). Conceptual specifications of the main equipments were designed for the hydrogen supply system consisting of hydrogenation and dehydrogenation process. It was also clarified the problems of hydrogen supply system, such as energy efficiency and system optimization. (author)

Piggy-back power supplies for magnet systems

International Nuclear Information System (INIS)

Gano, J.J.

1977-01-01

In accelerator facilities, particularly beam switchyards, it is common to have two or more related magnets which require nearly the same dc current. Presently the magnets are energized from separate sources, or from a single current-regulated source, with the magnets connected in series, and current-sink shunts across one or more of the magnets to obtain the difference. Advantages are discussed of economy, efficiency, reliability, and flexibility which accrue if auxiliary power supplies are used to trim the currents by the addition of more current to one or more magnets

A raster scanning power supply system for controlling relativistic heavy ion beams at the Bevalac Biomedical Facility

International Nuclear Information System (INIS)

Stover, G.; Nyman, M.; Halliwell, J.; Lutz, I.; Dwinell, R.

1987-03-01

A power supply system is currently being designed and constructed to sweep an 8.0 Tesla-meter relativistic heavy ion beam in a raster scanning mode for radiotherapy use. Two colinear dipole magnets with orthogonally oriented magnetic fields are driven by the system to produce a rectangular field (40 x 40 cm max.) with a uniform dose (+-2.5%) to a target volume 6 meters away. The ''fast'' horizontal scanning magnet is driven by a single power supply which in conjunction with a triac bridge network and a current regulated linear actuator will produce a 1200 cm/sec max. sweep rate. The ''slow'' (40 cm/sec) vertical scanning magnet will be controlled by dual current regulated linear actuators in a push-pull configuration. The scanner system can provide off-axis treatment profiles with large aspect ratios and unusual dimensions

Starting characteristics of direct current motors powered by solar cells

Science.gov (United States)

Singer, S.; Appelbaum, J.

1989-01-01

Direct current motors are used in photovoltaic systems. Important characteristics of electric motors are the starting to rated current and torque ratios. These ratios are dictated by the size of the solar cell array and are different for the various dc motor types. Discussed here is the calculation of the starting to rated current ratio and starting to rated torque ratio of the permanent magnet, and series and shunt excited motors when powered by solar cells for two cases: with and without a maximum-power-point-tracker (MPPT) included in the system. Comparing these two cases, one gets a torque magnification of about 3 for the permanent magnet motor and about 7 for other motor types. The calculation of the torques may assist the PV system designer to determine whether or not to include an MPPT in the system.

New supply for canyon fire foam system

International Nuclear Information System (INIS)

Gainey, T.

1995-01-01

The raw water supply for the B-Plant Canyon fire foam system is being replaced. The 4 inche water supply line to the foam system is being rerouted from the 6 inches raw water line in the Pipe Gallery to the 10 inches raw water main in the Operating Gallery. This document states the acceptance criteria for the flushing and testing to be performed by the contractor

Dynamic analysis of compact helical system power supply and designs of its upgrade

International Nuclear Information System (INIS)

Tanahashi, S.; Yamada, S.

1991-09-01

Computed dynamic waveforms are compared with measured ones for the power supply of the Compact Helical System (CHS) during 1.5T operation and found to be in good agreement. On the basis of these results, designs for the upgraded power supply for 2T operation are discussed in the two cases, with and without power consumption for additional heating. In the former case, the additional heating power is supplied from the ac generator that powers the CHS coils. Electric voltages and currents in the electric circuit are shown for both cases. These designs show the possibility for 2T operation by addition of some components without changing the ratings of existing components. (author)

Performance Characterization of a Lithium-ion Gel Polymer Battery Power Supply System for an Unmanned Aerial Vehicle

Science.gov (United States)

Reid, Concha M.; Manzo, Michelle A.; Logan, Michael J.

2004-01-01

Unmanned aerial vehicles (UAVs) are currently under development for NASA missions, earth sciences, aeronautics, the military, and commercial applications. The design of an all electric power and propulsion system for small UAVs was the focus of a detailed study. Currently, many of these small vehicles are powered by primary (nonrechargeable) lithium-based batteries. While this type of battery is capable of satisfying some of the mission needs, a secondary (rechargeable) battery power supply system that can provide the same functionality as the current system at the same or lower system mass and volume is desired. A study of commercially available secondary battery cell technologies that could provide the desired performance characteristics was performed. Due to the strict mass limitations and wide operating temperature requirements of small UAVs, the only viable cell chemistries were determined to be lithium-ion liquid electrolyte systems and lithium-ion gel polymer electrolyte systems. Two lithium-ion gel polymer cell designs were selected as candidates and were tested using potential load profiles for UAV applications. Because lithium primary batteries have a higher specific energy and energy density, for the same mass and volume allocation, the secondary batteries resulted in shorter flight times than the primary batteries typically provide. When the batteries were operated at lower ambient temperatures (0 to -20 C), flight times were even further reduced. Despite the reduced flight times demonstrated, for certain UAV applications, the secondary batteries operated within the acceptable range of flight times at room temperature and above. The results of this testing indicate that a secondary battery power supply system can provide some benefits over the primary battery power supply system. A UAV can be operated for hundreds of flights using a secondary battery power supply system that provides the combined benefits of rechargeability and an inherently safer

System engineering and design of a pulsed homopolar generator power supply for the Texas Experimental Tokamak

International Nuclear Information System (INIS)

Bird, W.L.; Grant, G.B.; Weldon, W.F.; Rylander, H.G.; Woodson, H.H.

1977-01-01

The design of a homopolar generator power supply for the Texas Experimental Tokamak (TEXT) is presented. Four series-connected disk type homopolar machines serve as inertial energy storage and conversion devices to supply 50 to 70 MW peak power to the toroidal field coil and ohmic heating coil circuits. The system is nominally operated at 150 MJ, 430 V to provide a 0.5 sec flat top, 160 kA TF current pulse and a 0.3 sec, 10 kA OH current pulse every 2.0 min on a continuous basis. The system has a maximum capacity of 200 MJ at a maximum open circuit voltage of 500 V. The homopolar machine design is described

Monitoring the Vulnerability of Energy Supply System

International Nuclear Information System (INIS)

Gnansonounou, E.

2006-01-01

Due to the increasing complexity of the world evolution, the public decision makers, the energy supply industry and the consumers in industrialised countries are more and more sensitive to the vulnerability of energy supply. The emergence of new big consumer countries and the perspective of oil and gas depletion at the end of the current century raise the concerns about how to share fairly the remaining resources for the common and sustainable development of the mankind. Erratic energy prices discourage investment and delay the energy transition. Voluntary measures are needed mainly in industrialised countries in order to develop alternative and sustainable energy sources and to avoid world struggle for energy procurement. In this contribution a synthetic energy vulnerability index is defined for monitoring energy supply vulnerability. The proposed index is based on energy intensity, oil and gas import dependency, CO 2 content of primary energy supply, electricity supply vulnerability and non-diversity in transport fuels. The preliminary assessment of this synthetic index for selected industrialised countries provides promising results that need however further refinement.(author)

Power-supply system for high-voltage electron guns with grid control

International Nuclear Information System (INIS)

Grigorev, Y.V.

1985-01-01

A power-supply system for electron guns with grid control is described which consists of a source of accelerating voltage between 20 and 180 kV with a current of 100 mA and a control circuit for an electron gun that contains a pulse generator having an output voltage of up to 5 kV for pulse durations of 2, 10, 50 and 90 microseconds. The output pulses of the generator are synchronized with a certain phase of the cathode heater current of the gun, and they can be repeated at a frequency between 100 and 0.4 Hz. The system is reliable and resistant to the overloads associated with breakdowns in the gun

EDDYMULT: a computing system for solving eddy current problems in a multi-torus system

International Nuclear Information System (INIS)

Nakamura, Yukiharu; Ozeki, Takahisa

1989-03-01

A new computing system EDDYMULT based on the finite element circuit method has been developed to solve actual eddy current problems in a multi-torus system, which consists of many torus-conductors and various kinds of axisymmetric poloidal field coils. The EDDYMULT computing system can deal three-dimensionally with the modal decomposition of eddy current in a multi-torus system, the transient phenomena of eddy current distributions and the resultant magnetic field. Therefore, users can apply the computing system to the solution of the eddy current problems in a tokamak fusion device, such as the design of poloidal field coil power supplies, the mechanical stress design of the intensive electromagnetic loading on device components and the control analysis of plasma position. The present report gives a detailed description of the EDDYMULT system as an user's manual: 1) theory, 2) structure of the code system, 3) input description, 4) problem restrictions, 5) description of the subroutines, etc. (author)

Public Water Supply Systems (PWS)

Data.gov (United States)

Kansas Data Access and Support Center — This dataset includes boundaries for most public water supply systems (PWS) in Kansas (525 municipalities, 289 rural water districts and 13 public wholesale water...

Prospects for development of heat supply systems in high-rise districts

Science.gov (United States)

Zhila, Viktor; Solovyeva, Elena

2018-03-01

The article analyzes the main advantages and disadvantages of centralized and decentralized heat supply systems in high-rise districts. The main schemes of centralized heat supply systems are considered. They include centralized heat supply from boiler houses, centralized heat supply from autonomous heat sources, heat supply from roof boiler houses and door-to-door heating supply. For each of these variant, the gas distribution systems are considered and analyzed. These systems vary depending on the heat source location. For each of these systems, technical and economic indicators are taken into account, the analysis of which allows choosing the best option for districts where high-rise buildings predominate.

Knowledge management system for risk mitigation in supply chain uncertainty: case from automotive battery supply chain

Science.gov (United States)

Marie, I. A.; Sugiarto, D.; Surjasa, D.; Witonohadi, A.

2018-01-01

Automotive battery supply chain include battery manufacturer, sulphuric acid suppliers, polypropylene suppliers, lead suppliers, transportation service providers, warehouses, retailers and even customers. Due to the increasingly dynamic condition of the environment, supply chain actors were required to improve their ability to overcome various uncertainty issues in the environment. This paper aims to describe the process of designing a knowledge management system for risk mitigation in supply chain uncertainty. The design methodology began with the identification of the knowledge needed to solve the problems associated with uncertainty and analysis of system requirements. The design of the knowledge management system was described in the form of a data flow diagram. The results of the study indicated that key knowledge area that needs to be managed were the knowledge to maintain the stability of process in sulphuric acid process and knowledge to overcome the wastes in battery manufacturing process. The system was expected to be a media acquisition, dissemination and storage of knowledge associated with the uncertainty in the battery supply chain and increase the supply chain performance.

Biased low differential input impedance current receiver/converter device and method for low noise readout from voltage-controlled detectors

Science.gov (United States)

Degtiarenko, Pavel V [Williamsburg, VA; Popov, Vladimir E [Newport News, VA

2011-03-22

A first stage electronic system for receiving charge or current from voltage-controlled sensors or detectors that includes a low input impedance current receiver/converter device (for example, a transimpedance amplifier), which is directly coupled to the sensor output, a source of bias voltage, and the device's power supply (or supplies), which use the biased voltage point as a baseline.

Transcutaneous Spinal Direct Current Stimulation (tsDCS

Directory of Open Access Journals (Sweden)

Filippo eCogiamanian

2012-07-01

Full Text Available In the past ten years renewed interest has centered on non-invasive transcutaneous weak direct currents applied over the scalp to modulate cortical excitability (brain polarization or transcranial direct current stimulation, tDCS. Extensive literature shows that tDCS induces marked changes in cortical excitability that outlast stimulation.Aiming at developing a new, non invasive, approach to spinal cord neuromodulation we assessed the after-effects of thoracic transcutaneous spinal DC stimulation (tsDCS on somatosensory potentials (SEPs evoked in healthy subjects by posterior tibial nerve (PTN stimulation. Our findings showed that thoracic anodal tsDCS depresses the cervico-medullary PTN-SEP component (P30 without eliciting adverse effects. tsDCS also modulates post-activation H-reflex dynamics. Later works further confirmed that transcutaneous electric fields modulate spinal cord function. Subsequent studies in our laboratory showed that tsDCS modulates the flexion reflex in the human lower limb. Besides influencing the laser evoked potentials, tsDCS increases pain tolerance in healthy subjects. Hence, though the underlying mechanisms remain speculative, tsDCS modulates activity in lemniscal, spinothalamic and segmental motor systems.Here we review currently available experimental evidence that non-invasive spinal cord stimulation influences spinal function in humans and argue that, by focally modulating spinal excitability, tsDCS could provide a novel therapeutic tool complementary to drugs and invasive spinal cord stimulation in managing various pathologic conditions, including pain.

Power supply for wireless sensor or actuator systems

International Nuclear Information System (INIS)

Reindl, L. M.

2011-01-01

Portable wireless sensor or actuator systems, like portable phones, remote control, or ID cards play an ever growing role in our industrialized environment. Those systems and many more were enabled due to the steady decreasing power consumption of high integrated ICs. Most such systems are powered by batteries or inductive coupling. In this presentation several concepts for an alternative power supply of wireless sensor or actuator systems are discussed in detail. Batteries, although today mostly used, suffer from a limited storage capacity, which induce a labour and sometimes cost-intensive periodic maintenance, and a problematic ecological impact. The operating range of inductive coupling systems is due to the near ?eld limited to the aperture of the coupling coil. UHF systems operate in the far field and reach higher distances. Their operating range is limited by the distance where the voltage at the feeding point of the antenna becomes too low to drive the rectifier circuit. Larger read out ranges become feasible by omitting the rectifier stage. In this case we need either a passive frequency modulating device to shift the read out signal to a side band, or a resonator with a high quality factor, like a SAW or BAW device, to store the energy until all environmental echoes are feed away. For many applications, both indoor and outdoor, energy harvesting system become feasible which convert ambient power densities like light, RF fields, special or temporal thermal gradients, or mechanical vibrations into electrical supply power of the wireless system. All those systems strongly suffer from a lack of energy. Thus new concepts for low-ering the power consumption of a wireless sensor or actuator system by keeping their features remain extreme important. Herby, a new wake up receiver is presented which operates on a current requirement as low as 3 micro A.

Performance of different types of renewable power supply systems

Energy Technology Data Exchange (ETDEWEB)

Al-Motawakel, M K [Sana' a Univ. (Republic of Yemen). Dept. of Physics; Abu-El-Eizz, H M; Awwad, Z [Zagazig Univ. (EG). Dept. of Physics

1991-10-01

In this paper we investigate the performance of a hybrid Photovoltaic (PV)-Wind generator power supply system operating under good and fair insolation and wind regimes. The effectiveness of such a hybrid system is measured by the Relative Sizing Parameter (RSP), Money Saving Parameter (MSP), and the Overall Reliability Parameter (ORP). Under specified weather conditions and for a nominal load demand, the RSP relates the product of the PV-modules and storage batteries involved in sizing the PV-Wind hybrid system to those of a stand alone PV-system sized to meet the same load. The MSP reports the difference between the total costs of a stand-alone PV power supply system and a hybrid PV-Wind power supply system, both sized to meet the same load, as a percentage of the total costs involved in supplying the load with a stand-alone PV power supply system only. The ORP compares the yearly average of the daily excess energy (positive difference between generated and consumed energy) of the hybrid system to that of the stand-alone PV power system. Based on this strategy we were able to develop a number of design diagrams which can be used in judging the benefits of utilizing hybrid PW-Wind generators on both economic and energy reliability grounds. (author).

Electric power supply I. AC systems, performance, economics. 3. rev. ed.; Elektrische Energieversorgung I. Drehstromsysteme, Leistungen, Wirtschaftlichkeit

Energy Technology Data Exchange (ETDEWEB)

Herold, Gerhard [Erlangen-Nuernberg Univ. (Germany)

2011-07-01

Since the beginning of its large-scale use, the electrical energy holds a key position in the process of sustainable energy development. The engineer now works with computers to the greatest possible extent. However, the results using powerful hardware and software are of little value when the specialist cannot interpret these results and implement these results in decisions. From this perspective, the author of the book under consideration reports on the fundamental aspects of the electrical energy supply. Thus, the main topics of this book are: (1) Construction of electric power supply systems; (2) Fundamentals of alternating current technology; (3) Transformations for three-phase systems; (4) Performance in electric power systems; (5) Economic power supply.

An analysis of control scheme and test results of fast feedback power supply

International Nuclear Information System (INIS)

Gupta, Shivam Kumar; Gupta, C.N.; Shah, Kunal; Makwana, Moti

2017-01-01

Real time Plasma Position Control is essential for obtaining long duration plasma in tokamaks. For that purpose four external coils has been installed in toroidal direction. Magnetic field of these coils interact with the plasma and tries to keep it radially stable in vacuum vessel to avoid direct contact of plasma to wall of tokamak. A fast feedback power supply has been installed in Aditya Tokamak which is able to set the appropriate current in either direction and current magnitude in external coils on the fast scale. In this paper, an analysis of control scheme and testing of Fast Feedback Power Supply (FFPS) has been described. FFPS is IGBT based H-bridge inverter programmable power supply

Power supply control system for experimental physical facilities

International Nuclear Information System (INIS)

Zelepukin, S.A.; Osipov, Eh.V.; Petrov, V.S.; Sergeev, V.A.; Uglekov, V.Ya.

1979-01-01

A multichannel (to 1024 channels) system for control of power supply voltage is descrited. The system consists of an analog commulator, a digital voltmeter and a special controller. The controller serves at the same time as an interface for connecting the system as a ''unit'' of the VECTOR and SUMMA unified electronic systems. The system has been realized for control of the photomultiplier power supply voltage of the MARK multipurpose experimental device (256 channels, the measurement accuracy is 0.2%, the measuring time is 500 ms per point). Software devised for the HP-2100 computer permits automatical comparison of photomultiplier power supply voltages with sample ones in the mode of continuous control of a single voltage or in the mode of programmed selection of voltages to provide the control in arbitrary order or automatic scanning

FPGA based control system for -100 kV, 25 A Crowbarless DC power supply

International Nuclear Information System (INIS)

Upadhyay, R.; Tripathi, A.; Badapanda, M.K.; Lad, M.

2015-01-01

FPGA based digital control system has been developed for -100 kV, 25 A solid state modular crowbarless DC klystron bias power supply of 1 MW, 352.2 MHz RF test stand. The control system has capability to operate this power supply either in CW or pulse mode. Central controller, PSM controller and graphical user interface are key parts of this control system. Central controller monitors the status of various subsystems of this power supply like 11 kV step start unit, four numbers of main transformers each having 44 numbers of secondary windings and 176 numbers of switch power modules for deciding the number of power modules to be put ON and their duty cycles depending on the set output voltage and current. PSM controller sends appropriate control signal to the switch power modules through fibre optic lines and communicates it to the central controller. Linux based graphical user interface has been developed which enables the user to set the operating parameters along with their trip limits and displays the information of critical parameters of this power supply on a local touch screen panel. Provision for remote control and supervision is also provided through a separate PC connected to the main control system via Ethernet. The control system has capability to trip the power supply within 5 μsec in case any parameter exceeds its set limit. Suitable data logging feature is incorporated for offline fault analysis. The control system architecture along with its software protection interlocks are presented in this paper. The performance of the control system has been verified during operation of -100 kV, 25 A DC power supply with 1 MW, 352.2 MHz klystron amplifier. (author)

Thyristor current-pulse generator for betatron electromagnet with independent low-voltage supply

International Nuclear Information System (INIS)

Baginskii, B.A.; Makarevich, V.N.; Shtein, M.M.

1989-01-01

A thyristor generator is described that produces unipolar current pulses in the winding of a betatron electromagnet. The voltage on the electro-magnet is increased and the shape of the current pulses is improved by use of an intermediate inductive storage device. The current pulses have a duration of 11 msec, an amplitude of 190 A, and a repetition frequency of 50 Hz. The maximum magnetic-field energy is 450 J, the voltage on the electromagnet winding is 1.5 kV, and the supply voltage is 27 V

The Complex Economic System of Supply Chain Financing

Science.gov (United States)

Zhang, Lili; Yan, Guangle

Supply Chain Financing (SCF) refers to a series of innovative and complicated financial services based on supply chain. The SCF set-up is a complex system, where the supply chain management and Small and Medium Enterprises (SMEs) financing services interpenetrate systematically. This paper establishes the organization structure of SCF System, and presents two financing models respectively, with or without the participation of the third-party logistic provider (3PL). Using Information Economics and Game Theory, the interrelationship among diverse economic sectors is analyzed, and the economic mechanism of development and existent for SCF system is demonstrated. New thoughts and approaches to solve SMEs financing problem are given.

Stability analysis of direct current control in current source rectifier

DEFF Research Database (Denmark)

Lu, Dapeng; Wang, Xiongfei; Blaabjerg, Frede

2017-01-01

Current source rectifier with high switching frequency has a great potential for improving the power efficiency and power density in ac-dc power conversion. This paper analyzes the stability of direct current control based on the time delay effect. Small signal model including dynamic behaviors...

Regulatory review and barriers for the electricity supply system for distributed generation in EU-15

DEFF Research Database (Denmark)

Ropenus, Stephanie; Skytte, Klaus

2005-01-01

When distributed electricity supply surpasses a particular level, it can no longer be ignored in planning and operation of the electricity networks. Therefore, improvements of the regulatory framework of the electricity networks are required along with the growth of the electricity supply from di...... distributed generation. This paper reviews the current regulation of the grids with respect to distributed generation in EU-15 Member States and compares the different systems. Several barriers are identified.......When distributed electricity supply surpasses a particular level, it can no longer be ignored in planning and operation of the electricity networks. Therefore, improvements of the regulatory framework of the electricity networks are required along with the growth of the electricity supply from...

Optimizing energy management of fuel cell-direct storage-hybrid systems; Optimierendes Energiemanagement von Brennstoffzelle-Direktspeicher-Hybridsystemen

Energy Technology Data Exchange (ETDEWEB)

Bocklisch, Thilo

2010-03-29

The dissertation presents a new optimizing energy management concept for fuel cell-direct storage-hybrid systems. Initially, the characteristics of specific energy time series are investigated on the basis of real measurement data. A new concept for the multi-scale analysis, modelling and prediction of fluctuating photovoltaic supply and electric load demand profiles is developed. The second part of the dissertation starts with a discussion of the benefits of and the basic coupling and control principles for fuel cell-direct storage-hybrid systems. The typical characteristics of a PEM-fuel cell, a metal hydride hydrogen storage, a lithium-ion battery and a supercap unit are presented. A new modular DC/DC-converter is described. Results from experimental and theoretical investigations of the individual components and the overall hybrid system are discussed. New practicable models for the voltage-current-curve, the state of charge behaviour and the conversion losses are presented. The third part of the dissertation explains the new energy management concept. The optimization of power flows is achieved by a control-oriented approach, employing a) the primary control of bus voltage and fuel cell current, b) the secondary control to limit fuel cell current gradient and operating range and to perform direct storage charge control, and c) the system control to optimally adjust secondary control parameters aiming for a reduction of dynamic fuel cell stress and hydrogen consumption. Results from simulations and experimental investigations demonstrate the benefits and high capabilities of the new optimizing energy management concept. Examples of stationary and portable applications conclude the dissertation. (orig.)

Optimal Control and Optimization of Stochastic Supply Chain Systems

CERN Document Server

Song, Dong-Ping

2013-01-01

Optimal Control and Optimization of Stochastic Supply Chain Systems examines its subject in the context of the presence of a variety of uncertainties. Numerous examples with intuitive illustrations and tables are provided, to demonstrate the structural characteristics of the optimal control policies in various stochastic supply chains and to show how to make use of these characteristics to construct easy-to-operate sub-optimal policies.                 In Part I, a general introduction to stochastic supply chain systems is provided. Analytical models for various stochastic supply chain systems are formulated and analysed in Part II. In Part III the structural knowledge of the optimal control policies obtained in Part II is utilized to construct easy-to-operate sub-optimal control policies for various stochastic supply chain systems accordingly. Finally, Part IV discusses the optimisation of threshold-type control policies and their robustness. A key feature of the book is its tying together of ...

JIT supply chain; an investigation through general system theory

Directory of Open Access Journals (Sweden)

O P Mishra

2013-03-01

Full Text Available This paper explains theoretical approach of the four theories of General system Theory (GST developed by Yourdon (1989 [Yourdon, E. (1989. Modern Structured Analysis. Yourdon Press, Prentice-Hall International, Englewood Cliffs, New Jersey. Senge] while applying it in information technology and subsequently used by caddy (2007 [Caddy I.N., & Helou, M.M. (2007. Supply chains and their management: Application of general systems theory. Journal of Retailing and Consumer Services, 14, 319–327.] in field of supply chain and management. JIT philosophy in core activities of supply chain i.e. procurement, production processes, and logistics are discussed through general system theory. The growing structure of the supply chain poses the implication restrictions and requires a heavy support system, many times a compromise is done while implementing JIT. The study would be useful to understand the general trends generated naturally regarding the adoption of the JIT philosophy in the supply chain.

Energy-Cost Optimisation in Water-Supply System

OpenAIRE

Farrukh Mahmood; Haider Ali

2013-01-01

Households as well as community water-supply systems for utilisation of underground aquifers are massive consumers of energy. Prevailing energy crisis and focus of the government on demand-side energy policies (i.e., energy conservation) in Pakistan raises need of using energy efficient techniques in almost every aspect of life. This paper analyses performance of community relative to household water-supply system in connection with efficient energy utilisation. Results suggest that total ope...

A concept for collaborative supply chain planning

DEFF Research Database (Denmark)

Alfnes, E.; Dreyer, H.C.; Hvolby, Hans-Henrik

2012-01-01

The main challenge for many manufacturers is the increased complexity of the supply chain, and as supply chains get more complicated enterprises require better tools for supply chain planning and execution. Many vendors offer systems to plan and control in-house operations, whereas mainly large...... vendors such as Oracle, SAP and I2 offer supply chain planning systems. This limits the ability for SMEs to exploit the supply chain planning options. This paper is part of a research project carried out to develop a new supply chain add-on for Microsoft AX, a very common system for SMEs. The paper...... discusses current supply chain planning solutions and presents a more simple and adaptive concept to be used in both SMEs and larger enterprises....

Upgrade of the Nuclotron power supply

International Nuclear Information System (INIS)

Karpinskij, V.N.; Kondrat'ev, N.G.; Osipenkov, A.L.

2010-01-01

One of topics of the Nuclotron development is the modification of its power supply scheme and upgrade of the energy evacuation system aimed to provide long and safe operation of the Nuclotron at the dipole magnetic field up to 2 T. It is necessary for the Nuclotron operation as a part of injection chain of the heavy ion collider under design at JINR as well as for fulfillment of its current scientific program. In the report the structure and peculiarity of the existing power supply system are described. The existing system is based on separated supply of dipole magnets and quadrupole lenses. General goals of the power supply modification are described, structural and principal schemes of the power supply, control system and the schemes of the energy evacuation key are presented

EOP Current Magnitude and Direction

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — These data contain shipboard current magnitudes and directions collected in the Pacific, both pelagic and near shore environments. Data is collected using an RD...

Control of supply temperature

Energy Technology Data Exchange (ETDEWEB)

Madsen, H; Nielsen, T S; Soegaard, H T

1996-09-01

For many district heating systems, e.g. the system in Hoeje Taastrup, it is desirable to minimize the supply temperature from the heat production unit(s). Lower supply temperature implies lower costs in connection with the production and distribution of heat. Factors having impact on the heat demand are for instance solar radiation, wind speed, wind direction and a climate independent part, which is a function of the time of the day/week/year. By applying an optimization strategy, which minimizes the supply temperature, it is assumed that optimal economical operation can be obtained by minimizing the supply temperature and thereby the heat losses in the system. The models and methods described in this report take such aspects into account, and can therefore be used as elements in a more efficient minimization of the supply temperature. The theoretical part of this report describes models and methods for optimal on-line control of the supply temperature in district heating systems. Some of the models and methods have been implemented - or are going to be implemented - in the computer program PRESS which is a tool for optimal control of supply temperature and forecasting of heat demand in district heating systems. The principles for using transfer function models are briefly described. The ordinary generalized predictive control (OGPC) method is reviewed, and several extensions of this method are suggested. New controller, which is called the extended generalized predictive controller (XGPC), is described. (EG) 57 refs.

Conducted noise analysis and protection of 45 kJ/s, ±50 kV capacitor charging power supply when interfaced with repetitive Marx based pulse power system

Science.gov (United States)

Naresh, P.; Patel, Ankur; Sharma, Archana

2015-09-01

Pulse power systems with highly dynamic loads like klystron, backward wave oscillator (BWO), and magnetron generate highly dynamic noise. This noise leads to frequent failure of controlled switches in the inverter stage of charging power supply. Designing a reliable and compatible power supply for pulse power applications is always a tricky job when charging rate is in multiples of 10 kJ/s. A ±50 kV and 45 kJ/s capacitor charging power supply based on 4th order LCLC resonant topology has been developed for a 10 Hz repetitive Marx based system. Conditions for load independent constant current and zero current switching (ZCS) are derived mathematically. Noise generated at load end due to dynamic load is tackled effectively and reduction in magnitude noise voltage is achieved by providing shielding between primary and secondary of high voltage high frequency transformer and with LCLC low pass filter. Shielding scales down the ratio between coupling capacitance (Cc) and the collector-emitter capacitance of insulated gate bi-polar transistor switch, which in turn reduces the common mode noise voltage magnitude. The proposed 4th order LCLC resonant network acts as a low pass filter for differential mode noise in the reverse direction (from load to source). Power supply has been tested repeatedly with 5 Hz repetition rate with repetitive Marx based system connected with BWO load working fine without failure of single switch in the inverter stage.

Comparison of centralized and decentralized energy supply systems

OpenAIRE

Pfeifer, Thomas; Fahl, Ulrich; Voß, Alfred

1991-01-01

Communal energy programs are often embedded in a conception of a decentralized energy supply system where electricity is produced by a number of smaller power plants. For a comprehensive survey the question arises whether these decentralized systems are more advantageous than centralized systems with regard to the criterions energy consumption, safety of supply, environmental compatibility and economy. In the following, after a definition of the term "decentralized", the present structure of ...

Advanced buck converter power supply ABCPS for APT

International Nuclear Information System (INIS)

Street, R.; Overett, T.; Bowles, E.

1998-01-01

The United States Department of Energy (DOE) is planning to fabricate an Accelerator for the Production of Tritium (APT) at their Savannah River Site, to provide Tritium for national defense. The 1700 million electron volt (MeV) proton beam accelerator will be powered by radio frequency (RF) klystrons. A direct current (DC) power supply is required for each of the approximately two hundred and fifty 1-megawatt (MW) continuous wave klystrons in the RF power system. The requirements are that the power supply meet output performance specifications, provide fault protection for the klystron, have high efficiency, high reliability, good maintainability, and be readily manufacturable. As the power supplies are one of the largest cost elements in the accelerator, a technology review was made to determine the most economical approach to satisfy the requirements. A switch-mode power supply employing a buck-regulator was identified as being potentially the lowest cost approach. As the switch represents a certain development risk, a small-scale prototype has been constructed for evaluation, and has resulted in the decision to fabricate a full-scale prototype power supply. A description of the hardware will be presented

Conflict nuclear power. Theses for current supply with and without nuclear power

International Nuclear Information System (INIS)

Schwarz, E.

2007-01-01

In the context of a lecture at the 2nd Internationally Renewable Energy Storage Conference at 19th to 21st November, 2007, in Bonn (Federal Republic of Germany), the author of the contribution under consideration reports on theses for current supply with and without nuclear power. (1) Theses for current supply with nuclear energy: Due to a relative amount of 17 % of nuclear energy in the world-wide energy production and due to the present reactor technology, the supplies of uranium amount nearly 50 to 70 years. The security of the nuclear power stations is controversially judged in the public and policy. In a catastrophic accident in a nuclear power station, an amount of nearly 2.5 billion Euro is available for adjustment of damages (cover note). The disposal of radioactive wastes is not solved anywhere in the world. The politically demanded separation between military and civilian use of the nuclear energy technology is not possible. The exit from the nuclear energy is fixed in the atomic law. By any means, the Federal Republic of Germany is not insulated in the European Union according to its politics of nuclear exit. After legal adjustment of the exit from the nuclear energy the Federal Republic of Germany should unfold appropriate activities for the re-orientation of Euratom, Nuclear Energy Agency and the International Atomic Energy Agency. The consideration of the use of nuclear energy in relation to the risks has to result that its current kind of use is not acceptable and to be terminated as fast as possible. (2) Theses for current supply without nuclear energy: The scenario technology enables a transparency of energy future being deliverable for political decisions. In accordance with this scenario, the initial extra costs of the development of the renewable energies and the combined heat and power generation amount approximately 4 billion Euro per year. The conversion of the power generation to renewable energies and combined heat and power generation

Development of protection system for power supply facilities in JT-60U P-NBI for long pulse operation

International Nuclear Information System (INIS)

Ohshima, Katsumi; Okano, Fuminori; Honda, Atsushi; Shinozaki, Shin-ichi; Usui, Katsutomi; Noto, Katsuya; Kawai, Mikito; Ikeda, Yoshitaka

2007-06-01

In the positive ion based NBI (P-NBI) system, we have developed a protection system to protect the power supply facilities from over load during long pulse operation. The protection system monitors the voltage (V) and current (I) in the power supply facilities, and calculates the parameters of V2t and I2t in real-time, where T is the pulse duration. It turns off the power supply facilities when V2t and I2t are beyond the critical values. After two development stages, we have completed the protection system using a package typed PLC (Programmable Logic Controller) which has a high expandability of multi-unit operation. Moreover, we have constructed a user-friendly system by using a SCADA (Supervisory Control and Data Acquisition) system. (author)

Transient Processes in Electric Power Supply System for Oil Terminal with Own Gas-Turbine Power Station

Directory of Open Access Journals (Sweden)

A. M. Hаshimov

2009-01-01

Full Text Available The paper contains results of the investigations concerning influence of symmetrical and non-symmetrical short circuits at main power network on electric power supply system of a huge oil terminal which is powered by own gas-turbine power station. Calculations have been made in accordance with the IEC and IEEЕ requirements. Estimations for voltage level and distribution of short circuit current in the electric power supply system of the Sangachal oil terminal being operated in parallel with the AzerEnerji grid are presented in the paper

Experimental Investigation of a Direct-drive Hall Thruster and Solar Array System at Power Levels up to 10 kW

Science.gov (United States)

Snyder, John S.; Brophy, John R.; Hofer, Richard R.; Goebel, Dan M.; Katz, Ira

2012-01-01

As NASA considers future exploration missions, high-power solar-electric propulsion (SEP) plays a prominent role in achieving many mission goals. Studies of high-power SEP systems (i.e. tens to hundreds of kilowatts) suggest that significant mass savings may be realized by implementing a direct-drive power system, so NASA recently established the National Direct-Drive Testbed to examine technical issues identified by previous investigations. The testbed includes a 12-kW solar array and power control station designed to power single and multiple Hall thrusters over a wide range of voltages and currents. In this paper, single Hall thruster operation directly from solar array output at discharge voltages of 200 to 450 V and discharge powers of 1 to 10 kW is reported. Hall thruster control and operation is shown to be simple and no different than for operation on conventional power supplies. Thruster and power system electrical oscillations were investigated over a large range of operating conditions and with different filter capacitances. Thruster oscillations were the same as for conventional power supplies, did not adversely affect solar array operation, and were independent of filter capacitance from 8 to 80 ?F. Solar array current and voltage oscillations were very small compared to their mean values and showed a modest dependence on capacitor size. No instabilities or anomalous behavior were observed in the thruster or power system at any operating condition investigated, including near and at the array peak power point. Thruster startup using the anode propellant flow as the power 'switch' was shown to be simple and reliable with system transients mitigated by the proper selection of filter capacitance size. Shutdown via cutoff of propellant flow was also demonstrated. A simple electrical circuit model was developed and is shown to have good agreement with the experimental data.

Experience of 12 kA / 16 V SMPS during the HTS Current Leads Test

Science.gov (United States)

Panchal, P.; Christian, D.; Panchal, R.; Sonara, D.; Purwar, G.; Garg, A.; Nimavat, H.; Singh, G.; Patel, J.; Tanna, V.; Pradhan, S.

2017-04-01

As a part of up gradation plans in SST-1 Tokamak, one pair of 3.3 kA rated prototype hybrid current leads were developed using Di-BSCCO as High Temperature Superconductors (HTS) and the copper heat exchanger. In order to validate the manufacturing procedure prior to go for series production of such current leads, it was recommended to test these current leads using dedicated and very reliable DC switch mode power supply (SMPS). As part of test facility, 12 kA, 16 VDC programmable SMPS was successfully installed, commissioned and tested. This power supply has special features such as modularity, N+1 redundancy, very low ripple voltage, precise current measurements with Direct Current Current Transformer, CC/CV modes with auto-crossover and auto-sequence programming. As a part of acceptance of this converter, A 5.8 mΩ water-cooled resistive dummy load and PLC based SCADA system is designed, developed for commissioning of power supply. The same power supply was used for the testing of the prototype HTS current leads. The paper describes the salient features and experience of state-of-art of power supply and results obtained from this converter during the HTS current leads test.

An integrated mine development and supply system

Energy Technology Data Exchange (ETDEWEB)

Muguira, T. [Brambles Coal Services, Newcastle, NSW (Australia)

1998-12-31

In the face of intense global competition and other business pressures on coal miners, ongoing quality initiatives and continuous process improvements are needed to enhance business performance. By viewing a minesite interms of key processes, rather than departments, and employing innovative technologies and better applying organisational resources, there exists enormous potential to achieve reductions in process cost and time. The paper identifies and selects one critical coal mining process, namely the supply system, to think about how productivity improvements might occur and what changes might be employed to enhance overall system performance. While the supply system is one of few processes existing at a minesite, the paper addresses only the supply process, but includes interaction across traditional interdepartmental boundaries. The paper has been prepared for a wide audience and is based on experience and observation at several underground mines however some of the concepts are a result of dreaming in the face of global competition. 3 refs., 1 tab.

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

DEFF Research Database (Denmark)

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

2005-01-01

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

Control system devices : architectures and supply channels overview.

Energy Technology Data Exchange (ETDEWEB)

Trent, Jason; Atkins, William Dee; Schwartz, Moses Daniel; Mulder, John C.

2010-08-01

This report describes a research project to examine the hardware used in automated control systems like those that control the electric grid. This report provides an overview of the vendors, architectures, and supply channels for a number of control system devices. The research itself represents an attempt to probe more deeply into the area of programmable logic controllers (PLCs) - the specialized digital computers that control individual processes within supervisory control and data acquisition (SCADA) systems. The report (1) provides an overview of control system networks and PLC architecture, (2) furnishes profiles for the top eight vendors in the PLC industry, (3) discusses the communications protocols used in different industries, and (4) analyzes the hardware used in several PLC devices. As part of the project, several PLCs were disassembled to identify constituent components. That information will direct the next step of the research, which will greatly increase our understanding of PLC security in both the hardware and software areas. Such an understanding is vital for discerning the potential national security impact of security flaws in these devices, as well as for developing proactive countermeasures.

Voltage Balancing Method on Expert System for 51-Level MMC in High Voltage Direct Current Transmission

Directory of Open Access Journals (Sweden)

Yong Chen

2016-01-01

Full Text Available The Modular Multilevel Converters (MMC have been a spotlight for the high voltage and high power transmission systems. In the VSC-HVDC (High Voltage Direct Current based on Voltage Source Converter transmission system, the energy of DC link is stored in the distributed capacitors, and the difference of capacitors in parameters and charge rates causes capacitor voltage balance which affects the safety and stability of HVDC system. A method of MMC based on the expert system for reducing the frequency of the submodules (SMs of the IGBT switching frequency is proposed. Firstly, MMC with 51 levels for HVDC is designed. Secondly, the nearest level control (NLC for 51-level MMC is introduced. Thirdly, a modified capacitor voltage balancing method based on expert system for MMC-based HVDC transmission system is proposed. Finally, a simulation platform for 51-level Modular Multilevel Converter is constructed by using MATLAB/SIMULINK. The results indicate that the strategy proposed reduces the switching frequency on the premise of keeping submodule voltage basically identical, which greatly reduces the power losses for MMC-HVDC system.

A new power supply for superconductive magnetic energy storage system

International Nuclear Information System (INIS)

Karady, G.G.; Han, B.M.

1992-01-01

In this paper a new power supply for a superconductive magnetic energy storage system, which permits a fast independent regulation of the active and reactive power, is presented. The power supply is built with several units connected in parallel. Each unit consists of a 24-pulse bridge converter, thyristor-switched tap-changing transformer, and thyristor-switched capacitor bank. Its system operation is analyzed by computer simulation and a feasible system realization is shown. A superconductive magnetic energy storage system with the proposed power supply has the capability of leveling the load variation, damping the low-frequency oscillation, and improving the transient stability in the power system. This power supply can be built with commercially available components using well-proven technologies

The Vanuatu medical supply system – documenting opportunities and challenges to meet the Millennium Development Goals

Science.gov (United States)

Brown, Andrew; Gilbert, Ben

2012-01-01

Objectives: Limited human resources are widely recognised as a barrier to achieve health-related Millennium Development Goals. Availability of medical supplies and suitably trained health personnel are crucial to ensuring a well-functioning medical supply system. The objective of this paper is to identify the factors which influence the availability of medical supplies within the health facilities of Vanuatu. Methods: A qualitative triangulated strategy using semi-structured interviews, observational workplace surveys and semi-structured focus groups was developed. This research was approved by the Human Ethics Committee of the University of Canberra and was funded through a direct grant from the United Nations Population Fund Suva, Pacific sub regional office. Results: During two weeks of data collection, 21 interviews were conducted, observational workplace surveys were completed in 19 facilities and 22 personnel participated in three focus groups across three provinces. The interviewees had a wide range of primary professional groupings and were representative of the Vanuatu health workforce. A complex array of medical supply issues are described from within the three tiered structure of the medical supply system. Conclusion: The results of this research have further informed our understanding of the competencies required by healthcare personnel to conduct medical supply management activities effectively in Pacific Island countries. As a result of this research, a platform is provided for the government of Vanuatu to engage development partners to work toward a sustainable medical supply system. PMID:23093895

Relay power supplies for the system of proton beam slow guidance onto internal targets of the Serpukhov synchrotron

International Nuclear Information System (INIS)

Belov, S.A.; Kardash, A.A.; Medvedev, V.A.; Perebejnos, V.K.; Shirokov, V.G.

1979-01-01

A static supply system for slow beam guiding on targets used in the IHEP synchrotron is discussed. As a regulating element use is made of a module-type gate bridge circuit. The power unit rated at an operating current of up to 200 A at a supply voltage of up to 200 V consists of 12 paralleled modules. Every module contains four transistors, four diodes and a part of a storage capacitor (200 μF). One module is rated at a current of 16 A. The regulator has been investigated in the pulse-width modulation mode and in the mode of relay control with normal and leading hysteresis loops. The minimum modulation of the secondary-particle beam density has been obtained when using leading hysteresis loops for regulation. In addition to the main task of guiding on targets the system provides shaping trapezoidal current pulses in the current range from 10 to 200 A at a current plateau stability of 0.5% and better

Saturable reactor-controlled power supply system for TCT/TFTR neutral beam sources

International Nuclear Information System (INIS)

Baker, W.R.; Hopkins, D.B.; Dexter, W.L.; Kuenning, R.W.; Smith, B.J.

1975-11-01

Each neutral beam source requires one major power supply, the acceleration supply, and four auxiliary power supplies. The power supplies are designed to permit independent interruption of current to any source and crowbarring within 20 μsec, in the event of a source spark, while not disturbing the normal pulsing of all other adjacent sources. The sources are described

Integral evaluation of energy supply systems at mountain refuges

Energy Technology Data Exchange (ETDEWEB)

Aschauer, C. [Univ. of Natural Resources and Applied Life Sciences, Vienna (Austria). Inst. for Chemical and Energy Engineering; Steinbacher, G. [Steinbacher and Steinbacher Civil Engineering Inc. (Austria); Weber, P. [DAV-Deutscher Alpenverein e.V. (Germany). Bundesgeschaeftsstelle; Deubler, Hubert

2010-07-01

Most of the mountain refuges scattered over the Alps (more than 1500) are not connected to public infrastructure, requiring decentralized supply and disposal and are therefore called island systems. The increasing number of guests goes along with a higher demand for comport and thus puts pressure on available resources. There are numerous challenges like remoteness, transport, low temperatures, seasonal operation and climate change to be faced. Furthermore, the supply and disposal system of an alpine hut has to merge different interests of the alpine associations, refuge operators, legal authorities and the alpine tourists. Therefore the respective infracstructure has to be managed as an overall-self-contained system. Energy supply is the central issue showing complex interaction with water supply, wastewater treatment and waste disposal. Many problems according to planning, decision-making, construction and operation concerning alpine infrastructure are reported. However detailed information on experiences made in these fields is missing at an international level so far. To correct this lack of data, the German Alpine Association (DAV) initiated the project ''Integral Evaluation of Supply and Disposal Systems of Mountain Refuges, IEVEBS'' in 2006, inviting all stakeholders (Alpine Associations, Legal Authorities, Planners, and Researchers) to participate. Additionally to the final project report which contains a detailed description and evaluation of the supply systems, guidelines will be elaborated in 2010 for planning, implementation and operation, all applicable at an international level. (orig.)

Designing Decentralized Water and Electricity Supply System for Small Recreational Facilities in the South of Russia

Science.gov (United States)

Kasharin, D. V.

2017-11-01

The article tackles the issues of designing seasonal water and power supply systems for small recreational facilities in the south of Russia based on intelligent decision support systems. The paper proposes modular prefabricated shell water and power supply works (MPSW&PW) along with energy-efficient standalone water-treatment plants as the principal facilities compliant with the environmental and infrastructural requirements applied to specially protected areas and ensuring the least possible damage to the environment due to a maximum possible use of local construction materials characterized by impressive safety margins in highly seismic environments. The task of designing water and power supply systems requires the consideration of issues pertaining to the development of an intelligent GIS-based system for the selection of water intake sites that facilitate automation of data-processing systems using a priori scanning methods with a variable step and random directions. The paper duly addresses such issues and develops parameterized optimization algorithms for MPSW&PW shell facilities. It equally provides the substantiation of water-treatment plants intelligent design based on energy recovery reverse osmosis and nanofiltration plants that enhance the energy efficiency of such plants serving as the optimum solution for the decentralized water supply of small recreational facilities from renewable energy sources.

Nuclear electronic equipment for control and monitoring boards. Specifications and test methods of direct current period meters

International Nuclear Information System (INIS)

Roquefort, Henri; Chapelot; Ramard; Tardif; Tournier; Vaux

1973-11-01

After a few words of introduction, mention of the main notations used and the definition of certain terms, the field of application of the document is outlined and a list of references given. The main specifications of electronic 'direct current period meter' subassemblies for the monitoring, control and safety of nuclear reactors are then defined and the corresponding test methods described. The apparatus measures on a logarithmic scale the neutron fluence rate of a reactor by means of an ionisation chamber and supplies 'period' data relative to the fluence rate variation in time. The specifications and test methods are given for the different components: logarithmic amplifier, time derivative unit, threshold releases, high tension supply for ionisation chamber, auxiliary circuits and finally the complete period meter. (author) [fr

MODEL BASED BIOMASS SYSTEM DESIGN OF FEEDSTOCK SUPPLY SYSTEMS FOR BIOENERGY PRODUCTION

Energy Technology Data Exchange (ETDEWEB)

David J. Muth, Jr.; Jacob J. Jacobson; Kenneth M. Bryden

2013-08-01

Engineering feedstock supply systems that deliver affordable, high-quality biomass remains a challenge for the emerging bioenergy industry. Cellulosic biomass is geographically distributed and has diverse physical and chemical properties. Because of this feedstock supply systems that deliver cellulosic biomass resources to biorefineries require integration of a broad set of engineered unit operations. These unit operations include harvest and collection, storage, preprocessing, and transportation processes. Design decisions for each feedstock supply system unit operation impact the engineering design and performance of the other system elements. These interdependencies are further complicated by spatial and temporal variances such as climate conditions and biomass characteristics. This paper develops an integrated model that couples a SQL-based data management engine and systems dynamics models to design and evaluate biomass feedstock supply systems. The integrated model, called the Biomass Logistics Model (BLM), includes a suite of databases that provide 1) engineering performance data for hundreds of equipment systems, 2) spatially explicit labor cost datasets, and 3) local tax and regulation data. The BLM analytic engine is built in the systems dynamics software package PowersimTM. The BLM is designed to work with thermochemical and biochemical based biofuel conversion platforms and accommodates a range of cellulosic biomass types (i.e., herbaceous residues, short- rotation woody and herbaceous energy crops, woody residues, algae, etc.). The BLM simulates the flow of biomass through the entire supply chain, tracking changes in feedstock characteristics (i.e., moisture content, dry matter, ash content, and dry bulk density) as influenced by the various operations in the supply chain. By accounting for all of the equipment that comes into contact with biomass from the point of harvest to the throat of the conversion facility and the change in characteristics, the

Assessing the vulnerability of public-supply wells to contamination--Glacial aquifer system in Woodbury, Connecticut

Science.gov (United States)

Jagucki, Martha L.; Brown, Craig J.; Starn, J. Jeffrey; Eberts, Sandra M.

2010-01-01

, as indicated by the solvents, fuel components, road salt, and septic-system leachate that were detected in the glacial aquifer system during the current study. Age-dating combined with chemical modeling suggests that less than 2 percent of water produced by the public-supply well is water from the deep bedrock that is "old" (water that recharged, or entered, the aquifer before 1952). Such a small percentage of old groundwater entering the public-supply well offers little potential for dilution of young waters containing contaminants from human activities. Shallow groundwater that originated as recharge through urban areas generally had higher median concentrations and more detections of volatile organic compounds (VOCs) than did groundwater from the deep glacial deposits or fractured bedrock that originated mainly as recharge through agricultural and undeveloped land. Shallow groundwater was also found to be affected by road salt and septic-system leachate. A chemical mixing model indicates that up to 15 percent of nitrate in water from the supply well is likely from septic-system leachate. The Connecticut Department of Public Health has identified several potential sources of contamination in the commercial area of Woodbury (several light industrial or commercial properties where hazardous materials and petroleum products are used and stored). To reduce stormwater runoff in the commercial area, water from the parking lots and pavement is channeled into dry wells-drains that shunt water directly into the aquifer system, bypassing the soil and unsaturated zones. A computer-model simulation of groundwater flow indicates that approximately 16 percent of the water produced by the public-supply well is derived from runoff captured by these drains. Traveltime for water from the dry wells to the public-supply well ranges from about 1.5 to less than 4 years. Dry wells have the potential to enhance contaminant movement to the supply well, suggesting that stormwater

Combined effects of cerebellar transcranial direct current stimulation and transcutaneous spinal direct current stimulation on robot-assisted gait training in patients with chronic brain stroke: A pilot, single blind, randomized controlled trial.

Science.gov (United States)

Picelli, Alessandro; Chemello, Elena; Castellazzi, Paola; Filippetti, Mirko; Brugnera, Annalisa; Gandolfi, Marialuisa; Waldner, Andreas; Saltuari, Leopold; Smania, Nicola

2018-01-01

Preliminary evidence showed additional effects of anodal transcranial direct current stimulation over the damaged cerebral hemisphere combined with cathodal transcutaneous spinal direct current stimulation during robot-assisted gait training in chronic stroke patients. This is consistent with the neural organization of locomotion involving cortical and spinal control. The cerebellum is crucial for locomotor control, in particular for avoidance of obstacles, and adaptation to novel conditions during walking. Despite its key role in gait control, to date the effects of transcranial direct current stimulation of the cerebellum have not been investigated on brain stroke patients treated with robot-assisted gait training. To evaluate the effects of cerebellar transcranial direct current stimulation combined with transcutaneous spinal direct current stimulation on robot-assisted gait training in patients with chronic brain stroke. After balanced randomization, 20 chronic stroke patients received ten, 20-minute robot-assisted gait training sessions (five days a week, for two consecutive weeks) combined with central nervous system stimulation. Group 1 underwent on-line cathodal transcranial direct current stimulation over the contralesional cerebellar hemisphere + cathodal transcutaneous spinal direct current stimulation. Group 2 received on-line anodal transcranial direct current stimulation over the damaged cerebral hemisphere + cathodal transcutaneous spinal direct current stimulation. The primary outcome was the 6-minute walk test performed before, after, and at follow-up at 2 and 4 weeks post-treatment. The significant differences in the 6-minute walk test noted between groups at the first post-treatment evaluation (p = 0.041) were not maintained at either the 2-week (P = 0.650) or the 4-week (P = 0.545) follow-up evaluations. Our preliminary findings support the hypothesis that cathodal transcranial direct current stimulation over the contralesional

Autonomous Energy Sources in the North of the Far East: Current State and Directions of Diversification

Directory of Open Access Journals (Sweden)

Boris Grigorievich Saneev

2018-03-01

Full Text Available The paper presents the current state of autonomous energy sources in the north of the Far East. Consideration is given to the capacity structures with a focus on industrial and residential autonomous energy sources. One of the main problems facing power supply to residential consumers in the north of the Far East is the insufficiently developed transport infrastructure, which causes complicated fuel delivery patterns, fuel price rise, and hence high electricity generation cost. The changes in the installed capacity of renewable energy sources (RES in the north of the Far East are demonstrated for the period between 2011 and 2015. The research shows the main directions of power production diversification in the north of the Far East. The directions include the use of local fuel types, the development of cogeneration, the involvement of renewable energy sources and small-scale nuclear power plants. The paper presents a forecast for the renewable energy development in the north of the Far East up to 2035, made by the authors. The priority RES projects in the off-grid power supply in the north of the Far East are wind and solar power plants

Supply assurance in the nuclear fuel cycle

International Nuclear Information System (INIS)

Neff, T.L.; Jacoby, H.D.

1979-01-01

Nuclear fuel assurance, in the face of world and political uncertainties, is interrelated with nuclear technology development plans and international safeguards considerations. This has led some countries to accelerate their commitments to nuclear commercialization faster than necessary and has made non-proliferation policies harder to enforce. Fuel assurance is described on a national basis in three time scales: short-term, or resilience to supply interruptions; mid-term, or contract conditions in which governments make commitments to purchase or deliver; and long-term, or resource adequacy. A review of former assurance problems and current trends in the enrichment and uranium markets indicates that supplier concentration is no longer the major problem so much as non-proliferation actions. The present state of unstable equilibrium is expected to move in the direction of less fuel-supply assurance for countries having a small market or not subscribing to non-proliferation criteria. The authors, while generally optimistic that the fuel-supply system will function, express concern that policies for fuel stockpiles and the condition of uranium markets need improvement. 21 references

Impacts of Large Scale Wind Penetration on Energy Supply Industry

Directory of Open Access Journals (Sweden)

John Kabouris

2009-11-01

Full Text Available Large penetration of Renewable Energy Sources (RES impacts Energy Supply Industry (ESI in many aspects leading to a fundamental change in electric power systems. It raises a number of technical challenges to the Transmission System Operators (TSOs, Distribution System Operators (DSOs and Wind Turbine Generators (WTG constructors. This paper aims to present in a thorough and coherent way the redrawn picture for Energy Systems under these conditions. Topics related to emergent technical challenges, technical solutions required and finally the impact on ESI due to large wind power penetration, are analyzed. Finally, general conclusions are extracted about the ESI current and future state and general directions are recommended.

The upgraded PSI application in the BEPCⅡ power supply control system

International Nuclear Information System (INIS)

Li Jiangqi; Wang Xiaoli; Wang Chunhong; Liu Jia

2011-01-01

There are about 460 magnet power supplies in the two rings and the transport lines of the BEPCⅡ which are controlled by the power supply controller and the power supply interface. An upgraded Power Supply Interface (PSI-Ⅱ) was developed for replacing the old one in the power supply control system of the BEPCⅡ. It will firstly describe feature of the PSI-Ⅱ and difference from the PSI. Then, discuss performance test of the PSI-Ⅱ well as its application in the power supply control system. (authors)

Successful use of e‐procurement in supply chains

OpenAIRE

Puschmann, Thomas; Alt, Rainer

2005-01-01

Purpose – Electronic support of internal supply chains for direct or production goods has been a major element during the implementation of enterprise resource planning (ERP) systems that has taken place since the late 1980s. However, supply chains to indirect material suppliers were not usually included due to low transaction volumes, low product values and low strategic importance of these goods. Dedicated information systems for streamlining indirect goods supply chains have emerged...

Application of drive circuit based on L298N in direct current motor speed control system

Science.gov (United States)

Yin, Liuliu; Wang, Fang; Han, Sen; Li, Yuchen; Sun, Hao; Lu, Qingjie; Yang, Cheng; Wang, Quanzhao

2016-10-01

In the experiment of researching the nanometer laser interferometer, our design of laser interferometer circuit system is up to the wireless communication technique of the 802.15.4 IEEE standard, and we use the RF TI provided by Basic to receive the data on speed control system software. The system's hardware is connected with control module and the DC motor. However, in the experiment, we found that single chip microcomputer control module is very difficult to drive the DC motor directly. The reason is that the DC motor's starting and braking current is larger than the causing current of the single chip microcomputer control module. In order to solve this problem, we add a driving module that control board can transmit PWM wave signal through I/O port to drive the DC motor, the driving circuit board can come true the function of the DC motor's positive and reversal rotation and speed adjustment. In many various driving module, the L298N module's integrated level is higher compared with other driver module. The L298N model is easy to control, it not only can control the DC motor, but also achieve motor speed control by modulating PWM wave that the control panel output. It also has the over-current protection function, when the motor lock, the L298N model can protect circuit and motor. So we use the driver module based on L298N to drive the DC motor. It is concluded that the L298N driver circuit module plays a very important role in the process of driving the DC motor in the DC motor speed control system.

Establishment of sustainable water supply system in small islands through rainwater harvesting (RWH): case study of Guja-do.

Science.gov (United States)

Han, Mooyoung; Ki, Jaehong

2010-01-01

Many islands in Korea have problems related to water source security and supply. In particular, the water supply condition is worse in small islands which are remote from the mainland. A couple of alternatives are developed and suggested to supply water to islands including water hauling, groundwater extraction, and desalination. However, these alternatives require much energy, cost, and concern in installation and operation. Rainwater harvesting is a sustainable option that supplies water with low energy and cost. However, lack of practical or comprehensive studies on rainwater harvesting systems in these regions hinders the promotion of the system. Therefore, this research examines defects of current RWH systems on an existing island, Guja-do, and provides technical suggestions in quantitative and qualitative aspects. A simple system design modification and expansion of system capacity using empty space such as a wharf structure can satisfy both the qualitative and the quantitative water demand of the island. Since rainwater harvesting is estimated to be a feasible water supply option under the Korean climate, which is an unfavorable condition for rainwater harvesting, implies a high potential applicability of rainwater harvesting technology to other regions over the world suffering from water shortage.

The MDSplus data acquisition system, current status and future directions

International Nuclear Information System (INIS)

Stillerman, J.; Fredian, T.W.

1999-01-01

The MDSplus data acquisition system was developed in collaboration with the ZTH group at Los Alamos National Laboratory and the RFX group at CNR in Padua, Italy and is currently in use at MIT, RFX in Padua, and TCV at EPFL in Lausanne. MDSplus is based on a hierarchical experiment description which completely describes the data acquisition and analysis tasks and contains the results from these operations. It also includes a set of X/motif based tools for data acquisition and display, as well as diagnostic configuration and management. These tools were designed to operate in a distributed, client/server environment with multiple concurrent readers and writers to the data store. An interface to a relational database is provided for storage and management of processed data. A commercially available package called IDL is used as the primary data analysis and visualization tool. The current projects include a new interface to the electronic logbook, tools for remote collaborators and WWW access, and a port of the system to UNIX and Windows-NT/95. (orig.)

Possibility of hydrogen supply by shared residential fuel cell systems for fuel cell vehicles

Directory of Open Access Journals (Sweden)

Ono Yusuke

2017-01-01

Full Text Available Residential polymer electrolyte fuel cells cogeneration systems (residential PEFC systems produce hydrogen from city gas by internal gas-reformer, and generate electricity, the hot water at the same time. From the viewpoint of the operation, it is known that residential PEFC systems do not continuously work but stop for long time, because the systems generate enough hot water for short operation time. In other words, currently residential PEFC systems are dominated by the amount of hot water demand. This study focuses on the idle time of residential PEFC systems. Since their gas-reformers are free, the systems have potential to produce hydrogen during the partial load operations. The authors expect that residential PEFC systems can take a role to supply hydrogen for fuel cell vehicles (FCVs before hydrogen fueling stations are distributed enough. From this perspective, the objective of this study is to evaluate the hydrogen production potential of residential PEFC systems. A residential PEFC system was modeled by the mixed integer linear programming to optimize the operation including hydrogen supply for FCV. The objective function represents annual system cost to be minimized with the constraints of energy balance. It should be noted that the partial load characteristics of the gas-reformer and the fuel cell stack are taken into account to derive the optimal operation. The model was employed to estimate the possible amount of hydrogen supply by a residential PEFC system. The results indicated that the system could satisfy at least hydrogen demand for transportation of 8000 km which is as far as the average annual mileage of a passenger car in Japan. Furthermore, hydrogen production by sharing a residential PEFC system with two households is more effective to reduce primary energy consumption with hydrogen supply for FCV than the case of introducing PEFC in each household.

Determination of optimal electrode positions for transcranial direct current stimulation (tDCS)

International Nuclear Information System (INIS)

Im, Chang-Hwan; Jung, Hui-Hun; Choi, Jung-Do; Lee, Soo Yeol; Jung, Ki-Young

2008-01-01

The present study introduces a new approach to determining optimal electrode positions in transcranial direct current stimulation (tDCS). Electric field and 3D conduction current density were analyzed using 3D finite element method (FEM) formulated for a dc conduction problem. The electrode positions for minimal current injection were optimized by changing the Cartesian coordinate system into the spherical coordinate system and applying the (2+6) evolution strategy (ES) algorithm. Preliminary simulation studies applied to a standard three-layer head model demonstrated that the proposed approach is promising in enhancing the performance of tDCS. (note)

Determination of optimal electrode positions for transcranial direct current stimulation (tDCS)

Energy Technology Data Exchange (ETDEWEB)

Im, Chang-Hwan; Jung, Hui-Hun; Choi, Jung-Do [Department of Biomedical Engineering, Yonsei University, Wonju, 220-710 (Korea, Republic of); Lee, Soo Yeol [Department of Biomedical Engineering, Kyung Hee University, Suwon (Korea, Republic of); Jung, Ki-Young [Korea University Medical Center, Korea University College of Medicine, Seoul (Korea, Republic of)], E-mail: ich@yonsei.ac.kr

2008-06-07

The present study introduces a new approach to determining optimal electrode positions in transcranial direct current stimulation (tDCS). Electric field and 3D conduction current density were analyzed using 3D finite element method (FEM) formulated for a dc conduction problem. The electrode positions for minimal current injection were optimized by changing the Cartesian coordinate system into the spherical coordinate system and applying the (2+6) evolution strategy (ES) algorithm. Preliminary simulation studies applied to a standard three-layer head model demonstrated that the proposed approach is promising in enhancing the performance of tDCS. (note)

City gas supply management system. Toshi gas kyokyu kanri system

Energy Technology Data Exchange (ETDEWEB)

Ota, S [Tokyo Gas Co. Ltd., Tokyo (Japan)

1991-07-05

Supply and control system of city gas (about 90% is LNG) at Tokyo Gas Company is summarized. The LNG is delivered from the high pressure, A-middle pressure and B-middle pressure stations through the low pressure governors at about 3,000 locations to the low-pressure conduit networks. The information system department uses a large-size general purpose IBM computer as a host computer, control computers at each station, and communication networks consisted mainly of the in-house wireless networks. The trunk lines are all looped, and the important facilities are dualized. Characteristic functions include the supply prediction, which takes into account the past supply and ambient temperature records, a day of the week for a particular date, and demand fluctuation trends; adjustments of each holder based on the prediction and restrictions; and piping network simulation to decide gas manufacturing patterns, and determine reasonability of local construction of complicated conduits. The monitoring and control system as the central nerve includes a quick block-wide operation at an accident from earthquake and the like to prevent wide area disasters. 8 figs., 1 tab.

Photovoltaic / Diesel / Battery Hybrid Power Supply System

CSIR Research Space (South Africa)

Tazvinga, Henerica

2010-10-01

Full Text Available (SOPAC Miscellaneous Report 406, 2005). The battery bank is cycled frequently, shortening its lifetime. If the inverter fails there is complete loss of power to the load, unless the load can be supplied directly from the diesel generator for emergency purposes....5 Sizing the inverter ............................................................................................... 67 5.6 Sizing the charge Controller ............................................................................... 68 5.7 Sizing...

Leaks in the internal water supply piping systems

OpenAIRE

Orlov Evgeniy Vladimirovich; Komarov Anatoliy Sergeevich; Mel’nikov Fedor Alekseevich; Serov Aleksandr Evgen’evich

2015-01-01

Great water losses in the internal plumbing of a building lead to the waste of money for a fence, purification and supply of water volumes in excess. This does not support the concept of water conservation and resource saving lying today in the basis of any building’s construction having plumbing. Leakage means unplanned of water losses systems in domestic water supply systems (hot or cold) as a result of impaired integrity, complicating the operation of a system and leading to high costs of ...

A dual mode operated boost inverter and its control strategy for ripple current reduction in single-phase uninterruptible power supplies

DEFF Research Database (Denmark)

Tang, Y.; Yao, W.; Blaabjerg, Frede

2015-01-01

In single-phase uninterruptible power supply (UPS) applications, it is well known that the AC side instantaneous power is not constant by nature. The resulting input current from the DC source side will inevitably contain low frequency ripple components that may largely deteriorate the system...... as active power conversion, while its CM operation is controlled in such a way that the low frequency ripple current on the DC side can be maintained in a minimum level. The proposed ripple current reduction method may not only work with linear loads, but also nonlinear loads, where more sophisticated...

Protection of the MFTF accel power supplies

International Nuclear Information System (INIS)

Wilson, J.H.; Wood, J.C.

1979-01-01

The MFTF experiment's Sustaining Neutral Beam Power Supply System (SNBPSS) includes twenty-four 95 kV, 80 A accel dc power supplies (ADCPS). Each power supply includes a relatively high-impedance (20 percent) rectifier transformer and a step voltage regulator with a 50-100 percent voltage range. With this combination, the fault current for some postulated faults may be lower than the supply's full load current at maximum voltage. A design has been developed which uses protective relays and current-limiting fuses coordinated to detect phase and ground faults, DC faults, incorrect voltage conditions, rectifier faults, power factor correction capacitor faults, and overloads. This unusual solution ensures fast tripping on potentially destructive high-current faults and long-time delays at lower currents to allow 30 second pulse operation. The ADCPS meets the LLL specification that all major assemblies be self-protecting, that is, able to sustain external faults without damage to minimize damage due to internal faults

Multiplicity in public health supply systems: a learning agenda.

Science.gov (United States)

Bornbusch, Alan; Bates, James

2013-08-01

Supply chain integration-merging products for health programs into a single supply chain-tends to be the dominant model in health sector reform. However, multiplicity in a supply system may be justified as a risk management strategy that can better ensure product availability, advance specific health program objectives, and increase efficiency.

Supply Chain Collaboration Roles of Interorganizational Systems, Trust, and Collaborative Culture

CERN Document Server

Cao, Mei

2013-01-01

To survive and thrive in the competition, firms have strived to achieve greater supply chain collaboration to leverage the resources and knowledge of suppliers and customers.  Internet based technologies, particularly interorganizational systems, further extend the firms’ opportunities to strengthen their supply chain partnerships and share real-time information to optimize their operations.  Supply Chain Collaboration: Roles of Interorganizational Systems, Trust, and Collaborative Culture explores the nature and characteristics, antecedents, and consequences of supply chain collaboration from multiple theoretical perspectives.  Supply Chain Collaboration: Roles of Interorganizational Systems, Trust, and Collaborative Culture conceptualizes supply chain collaboration as seven interconnecting elements including information sharing, incentive alignment, goal congruence, decision synchronization, resource sharing, as well as communication and joint knowledge creation. These seven components define the occur...

Assessing reliability in energy supply systems

International Nuclear Information System (INIS)

McCarthy, Ryan W.; Ogden, Joan M.; Sperling, Daniel

2007-01-01

Reliability has always been a concern in the energy sector, but concerns are escalating as energy demand increases and the political stability of many energy supply regions becomes more questionable. But how does one define and measure reliability? We introduce a method to assess reliability in energy supply systems in terms of adequacy and security. It derives from reliability assessment frameworks developed for the electricity sector, which are extended to include qualitative considerations and to be applicable to new energy systems by incorporating decision-making processes based on expert opinion and multi-attribute utility theory. The method presented here is flexible and can be applied to any energy system. To illustrate its use, we apply the method to two hydrogen pathways: (1) centralized steam reforming of imported liquefied natural gas with pipeline distribution of hydrogen, and (2) on-site electrolysis of water using renewable electricity produced independently from the electricity grid

Power supplies in 14 UD pelletron accelerator and its control (Paper No. CP 12)

International Nuclear Information System (INIS)

Vaze, M.Y.; Bhalerao, P.J.; Tambvekar, V.V.

1990-01-01

14UD Pelletron is a 14 million volt tandem heavy ion accelerator. For generation of the accelerating voltage, heavy ion beams and transporting the beam through low energy injector systems, accelerator, high energy system, analysing magnets and finally upto the target different types of types of D.C. power supplies with varying capacity and specifications are used in this accelerator. Broadly these power supplies can be classified in three different types: (1)D.C. high voltage low current voltage regulated supplies, (2)Low voltage high current current regulated high precision D.C. power supplies, and (3)Medium power current regulated D.C. power supplies. These power supplies are described and systems where they are used are mentioned. They are interfaced with CAMAC module and are controlled and monitored remotely from the control room through the serial highway link. (author). 2 figs

Some new directions in system transient simulation

International Nuclear Information System (INIS)

Ransom, V.H.

1986-01-01

The current research in system transient simulation at the Idaho National Engineering Laboratory (INEL) is summarized in this paper and three new directions that are emerging from this work are discussed. The new directions are: development of an Advanced Thermal Hydraulic Energy Network Analyzer (ATHENA) having new modeling capability, use of expert systems for enhancing simulation methods, and the trend to individual workstations for simulation

A novel flattop current regulated energy discharge type pulsed power supply and magnet yielding 4.4 kGauss-meter for 6 milliseconds

International Nuclear Information System (INIS)

Visser, A.T.

1989-07-01

Most energy discharge power supplies obtain their bursts of power from the energy stored in charged capacitors when it is suddenly released into a load. This note describes the design of a similar small 800 Joules energy discharge type power supply and magnet. The magnet gap is 2 in.x2 in.x25-1/2 in. long and produces about 4.4 kGauss-meters at a rate of 12 pulses per minute. Each pulse is current regulated at the top for a duration of 6 msec. and varies less than 0.6% of set value. Current regulation at flattop is obtained by switching a resistor in and out of the discharge circuit with an IGBT at a rate of about 5 kHz. Most energy discharge systems produce half sine wave pulses, and current regulation is obtained by controlling the charge voltage at the energy storage capacitor, resulting only in a controlled peak current value of the half sine wave pulse. The current value at the top changes substantially during 6 msec. depending on the operating frequency

Operational experience with -20 kV, 5 A DC power supply in Indus-2 RF system

International Nuclear Information System (INIS)

Tyagi, R.K.; Tripathi, A.; Upadhyay, R.; Badapanda, M.K.; Lad, M.

2015-01-01

An AC regulator based -20 kV, 5 A DC power supply is employed to bias 60 kW, 505.8 MHz klystron amplifier in Indus-2 RF system. A three terminal triggered spark gap based crowbar along with suitable limiting elements is incorporated at the output of the power supply for protection of sensitive klystron amplifier during load arcing conditions. Wire burn test is carried out on this power supply along with crowbar to ensure that the stored energy dumped into klystron during its arcing is less than 20 Joule. Various protection circuits like over voltage, over current, under voltage, phase failure, thermal overload and transformer oil over temperature protection have been incorporated in this power supply. Preventive maintenance of the power supply is carried out at regular intervals to ensure that it operates satisfactorily during actual operation.This includes checking the breakdown strength of transformer oil, drying of Silica gels in transformer breathers, checking of all electrical connections and cleaning of all high voltage components. The calibration of various meters, checking the setting of various protection-interlock cards and checking the healthiness of crowbar system are also done at regular intervals. During operation, crucial performance parameters of this power supply along with various interlock signals are continuously monitored. Suitable arrangement has been made to operate this supply either in local mode as well as in remote mode. This power supply is operating satisfactorily with klystron amplifier in Indus-2 RF system in round the clock mode for last 15 years and its operational experience are presented in this paper. (author)

Finance and supply management project execution plan

Energy Technology Data Exchange (ETDEWEB)

BENNION, S.I.

1999-02-10

As a subproject of the HANDI 2000 project, the Finance and Supply Management system is intended to serve FDH and Project Hanford major subcontractor with financial processes including general ledger, project costing, budgeting, and accounts payable, and supply management process including purchasing, inventory and contracts management. Currently these functions are performed with numerous legacy information systems and suboptimized processes.

Business Intelligence tools as an element of information supply system

Directory of Open Access Journals (Sweden)

Agnieszka Szmelter

2013-12-01

Full Text Available This paper aims to present theBusiness Intelligence toolsas an element improvingflow of information withinthe management information systemand as atool to facilitate theachieving the objectives ofinformation supply system.In the firstpart of the paperthe author presents the issuesrelatedto the specific character of information as a kind of resource and functioning ofthe information supply systemin the enterprise. The secondpart of the articleincludethe characteristics ofBusiness Intelligence systems. The thirdpart deals withthe impact ofBusiness Intelligence toolsto the ongoingactivities ofinformation supply system.

Modular high voltage power supply for chemical analysis

Science.gov (United States)

Stamps, James F [Livermore, CA; Yee, Daniel D [Dublin, CA

2008-07-15

A high voltage power supply for use in a system such as a microfluidics system, uses a DC-DC converter in parallel with a voltage-controlled resistor. A feedback circuit provides a control signal for the DC-DC converter and voltage-controlled resistor so as to regulate the output voltage of the high voltage power supply, as well as, to sink or source current from the high voltage supply.

Urban community perception towards intermittent water supply system.

Science.gov (United States)

Joshi, M W; Talkhande, A V; Andey, S P; Kelkar, P S

2002-04-01

While evaluating intermittent and continuous water supply systems, consumers opinion survey was undertaken for critical appraisal of both modes of operation. With the help of a pre-designed set of questions relating to various aspects of water supply and the opinion of consumers regarding degree of service, a house to house survey was conducted in the study area of Ghaziabad and Jaipur. The consumer opinion survey clearly indicated a satisfactory degree of service wherever adequate quantity of water was made available irrespective of the mode of water supply. Number of complaints regarding quality of water supplied, timings of supply, low pressures and breakdowns in supply were reported during intermittent water supply. Every family stored water for drinking and other uses. Most of the families discard drinking water once the fresh water supply is resumed next day. Discarded drinking water is usually used in kitchen for washing and gardening. Storage for other purposes depends on economic status and availability of other sources like open dug well in the house. While most of the respondents had no complaints on water tariff, all of them were in favour of continuous water supply.

Method and system for a gas tube switch-based voltage source high voltage direct current transmission system

Science.gov (United States)

She, Xu; Chokhawala, Rahul Shantilal; Zhou, Rui; Zhang, Di; Sommerer, Timothy John; Bray, James William

2016-12-13

A voltage source converter based high-voltage direct-current (HVDC) transmission system includes a voltage source converter (VSC)-based power converter channel. The VSC-based power converter channel includes an AC-DC converter and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and a DC-AC inverter include at least one gas tube switching device coupled in electrical anti-parallel with a respective gas tube diode. The VSC-based power converter channel includes a commutating circuit communicatively coupled to one or more of the at least one gas tube switching devices. The commutating circuit is configured to "switch on" a respective one of the one or more gas tube switching devices during a first portion of an operational cycle and "switch off" the respective one of the one or more gas tube switching devices during a second portion of the operational cycle.

System Description of the Electrical Power Supply System for the ATLAS Integral Test Loop

International Nuclear Information System (INIS)

Moon, S. K.; Park, J. K.; Kim, Y. S.; Song, C. H.; Baek, W. P.

2007-02-01

An integral effect test loop for pressurized water reactors (PWRs), the ATLAS (Advanced Thermal-hydraulic Test Loop for Accident Simulation), is constructed by Thermal-Hydraulics Safety Research Team in Korea Atomic Energy Research Institute (KAERI). The ATLAS facility has been designed to have the length scale of 1/2 and area scale of 1/144 compared with the reference plant, APR1400. This report describes the design and technical specifications of the electrical power supply system which supplies the electrical powers to core heater rods, other heaters, various pumps and other systems. The electrical power supply system had acquired the final approval on the operation from the Korea Electrical Safety Corporation. During performance tests for the operation and control, the electrical power supply system showed completely acceptable operation and control performance

Performance Analyses of Renewable and Fuel Power Supply Systems for Different Base Station Sites

Directory of Open Access Journals (Sweden)

Josip Lorincz

2014-11-01

Full Text Available Base station sites (BSSs powered with renewable energy sources have gained the attention of cellular operators during the last few years. This is because such “green” BSSs impose significant reductions in the operational expenditures (OPEX of telecom operators due to the possibility of on-site renewable energy harvesting. In this paper, the green BSSs power supply system parameters detected through remote and centralized real time sensing are presented. An implemented sensing system based on a wireless sensor network enables reliable collection and post-processing analyses of many parameters, such as: total charging/discharging current of power supply system, battery voltage and temperature, wind speed, etc. As an example, yearly sensing results for three different BSS configurations powered by solar and/or wind energy are discussed in terms of renewable energy supply (RES system performance. In the case of powering those BSS with standalone systems based on a fuel generator, the fuel consumption models expressing interdependence among the generator load and fuel consumption are proposed. This has allowed energy-efficiency comparison of the fuel powered and RES systems, which is presented in terms of the OPEX and carbon dioxide (CO2 reductions. Additionally, approaches based on different BSS air-conditioning systems and the on/off regulation of a daily fuel generator activity are proposed and validated in terms of energy and capital expenditure (CAPEX savings.

Supply systems of forest chip production in Finland

Energy Technology Data Exchange (ETDEWEB)

Kaerhae, K. (Metsaeteho Oy, Helsinki (Finland)), e-mail: kalle.karha@metsateho.fi

2010-07-01

The Metsaeteho study investigated how logging residue chips, stump wood chips, and chips from small-diameter thinning wood and large-sized (rotten) roundwood used by heating and power plants were produced in Finland in 2009. Almost all the major forest chip suppliers in Finland were involved in the study. The total volume of forest chips supplied in 2009 by these suppliers was 8,4 TWh. The study was implemented by conducting an e-mail questionnaire survey and telephone interviews. Research data was collected from March-May, 2010. The majority of the logging residue chips and chips from small-diameter thinning wood were produced using the roadside chipping supply system in Finland in 2009. The chipping at plant supply system was also significant in the production of logging residue chips. Nearly 70 % of all stump wood chips consumed were comminuted at the plant and 28 % at terminals. The role of the terminal chipping supply system was also significant in the production of chips from logging residues and small-diameter wood chips. When producing chips from large-sized (rotten) roundwood, similarly roughly 70 % of chips were comminuted at plants and 23 % at terminals. (orig.)

Flexibility of Supply Chain in Industrialised Building System (IBS

Directory of Open Access Journals (Sweden)

Kassim U.

2014-01-01

Full Text Available It is irrefutable that the construction industry is in need of a highly technological construction method or system for the simple aim of giving it a push it deserves. In Malaysia this technologically enhanced method is known as the Indutrialised Building System (IBS. Concerted efforts have been made for the past decade by various responsible parties especially by the government. Therefore, the IBS ‘Road Map’ 2003–2010 was introduced and now continues with the IBS ‘road map’ 2011-2015. However, its performance is still at its infancy, which target is only at an initial stage. This study seeks to identify and analyse the factor of the IBS’ system’s supply chain flexibility as a factor on the success of the system itself. It has been a suspicion that there exists a condition and situation where the supply chain is too rigid and is not flexible in fulfilling the needs and demands of the IBS development in Malaysia. This inflexible situation has brought about a broad range of problems and has stood in the way of the development of the industrialised building system, despite it being introduced since 1964, or 49 years ago. Flexibility in the IBS supply chain is very important and is associated with other industries like transportation, manufacturing industry, and others. Up until now, we have yet to discover any special studies related to the flexibility in the IBS supply chain in this country. Responding to this challenge, this research is hoped to be able to provide sufficient feedback to the solution to the IBS supply chain flexibility issue. The researcher is confident that the poor system flow of supply chain has impeded the advancement of the Industrialised Building System that has long been open to debate.

A supply chain approach to biochar systems [Chapter 2

Science.gov (United States)

Nathaniel M. Anderson; Richard D. Bergman; Deborah S. Page-Dumroese

2017-01-01

Biochar systems are designed to meet four related primary objectives: improve soils, manage waste, generate renewable energy, and mitigate climate change. Supply chain models provide a holistic framework for examining biochar systems with an emphasis on product life cycle and end use. Drawing on concepts in supply chain management and engineering, this chapter presents...

Power supply connection for ionizing radiation detection probes

International Nuclear Information System (INIS)

Zajic, J.

1990-01-01

One wire of the supply line is connected, through a diode in the forward direction, to the input terminal of the voltage stabilizer, and through the first resistor to the current limiter terminal of the voltage stabilizer, and also directly to the pulse separator terminal. The current limiter terminal of the voltage stabilizer is connected, through the second resistor, to the output terminal of the voltage stabilizer, and through the first capacitor to the voltage stabilizer earthing terminal, the earthing terminal of the pulse separator and through the other wire of the supply line to the earthing terminal of the detection probe. Furthermore, the input terminal of the voltage stabilizer is connected to a parallel combination of the third resistor with the second capacitor, whose other end is connected to the earthing terminal of the voltage stabilizer. The main asset of this connection consists in the high-frequency matching of the supply line being accomplished by a suitable choice of the resistor value without affecting the voltage for the detection probe. (M.D.)

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

CERN Document Server

Chaudhuri, Nilanjan; Majumder, Rajat; Yazdani, Amirnaser

2014-01-01

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

Systemic Analysis of Food Supply and Distribution Systems in City-Region Systems—An Examination of FAO’s Policy Guidelines towards Sustainable Agri-Food Systems

Directory of Open Access Journals (Sweden)

Vanessa Armendáriz

2016-12-01

Full Text Available The world is continuously transforming to supply growing cities and urbanization processes are still driving important changes in our current food systems. Future sustainability constraints are emphasizing that Food Supply and Distribution Systems (FSDS are deeply embedded in city-region systems with specific technical and socio-ecological characteristics. This paper aims to provide a systemic understanding on FSDS focusing the integration of urban and rural structures considering the system biophysical boundaries and societal targets. A qualitative framework model, based on the Food and Agriculture Organization of the United Nations (FAO’s FSDS literature, has been developed by using Systems Thinking (ST and System Dynamics (SD approaches. The model analysis suggested that to increase sustainability and resilience of food systems large emphasis has to be maintained on: (i estimation of local territorial carrying capacities; (ii land use planning to enhance connections among rural supplies and city needs; (iii city policies, to regulate emergent market size and local scale of production; (iv technological efficiency at farm, distribution and market levels; (v urban, peri-urban and rural functional linkages that considers social metabolic balances; (vi rural development as a core point for building sustainable food systems and counteracting the urbanization growth. These key areas are relevant to test new paths of cities-regions reconfiguration towards the transition to resilient agri-food systems.

Numerical study on oil supply system of a rotary compressor

International Nuclear Information System (INIS)

Wu, Jianhua; Wang, Gang

2013-01-01

The oil supply system is a crucial reliability issue for rotary compressors. This paper provides a general method for analyzing the oil supply system of a rotary compressor by using computational fluid dynamics (CFD). The process includes establishing the physical model, dividing computational grid, setting boundary conditions, calculating leakage rates through the roller end clearances, translating the dynamic issue into the static issue and so on. Validation of the rationality of the oil supply system model has been made by the measurement of the main bearing oil flow rates. The effects of operating conditions of the compressor, the oil level height of the oil sump and the main design parameters of the oil supply system on the oil supply characteristics are analyzed by numerical simulation. It is found that the main bearing oil flow rate varies circularly along with the rotation of the shaft. The shape and inclination angle of the spiral groove also influence the main bearing oil flow rate. The oil leakage rates through the roller end clearances depend largely on the operating conditions. In addition, the oil level height of the oil sump has a huge effect on the total oil flow rate. -- Highlights: • A CFD method for analyzing the oil supply system of rotary compressor is presented. • Leakage through the roller end clearances depends on the operating condition. • Groove shape and inclination angle are the main design parameters of spiral grooves. • A parabolic interface of oil and gas can be formed in the gallery of the shaft. • Single-flow model and steady solver can be applied to the oil supply system

Risk of the Maritime Supply Chain System Based on Interpretative Structural Model

Directory of Open Access Journals (Sweden)

Jiang He

2017-11-01

Full Text Available Marine transportation is the most important transport mode of in the international trade, but the maritime supply chain is facing with many risks. At present, most of the researches on the risk of the maritime supply chain focus on the risk identification and risk management, and barely carry on the quantitative analysis of the logical structure of each influencing factor. This paper uses the interpretative structure model to analysis the maritime supply chain risk system. On the basis of comprehensive literature analysis and expert opinion, this paper puts forward 16 factors of maritime supply chain risk system. Using the interpretative structure model to construct maritime supply chain risk system, and then optimize the model. The model analyzes the structure of the maritime supply chain risk system and its forming process, and provides a scientific basis for the controlling the maritime supply chain risk, and puts forward some corresponding suggestions for the prevention and control the maritime supply chain risk.

Contraception supply chain challenges: a review of evidence from low- and middle-income countries.

Science.gov (United States)

Mukasa, Bakali; Ali, Moazzam; Farron, Madeline; Van de Weerdt, Renee

2017-10-01

To identify and assess factors determining the functioning of supply chain systems for modern contraception in low- and middle-income countries (LMICs), and to identify challenges contributing to contraception stockouts that may lead to unmet need. Scientific databases and grey literature were searched including Database of Abstracts of Reviews of Effectiveness (DARE), PubMed, MEDLINE, POPLINE, CINAHL, Academic Search Complete, Science Direct, Web of Science, Cochrane Central, Google Scholar, WHO databases and websites of key international organisations. Studies indicated that supply chain system inefficiencies significantly affect availability of modern FP and contraception commodities in LMICs, especially in rural public facilities where distribution barriers may be acute. Supply chain failures or bottlenecks may be attributed to: weak and poorly institutionalized logistic management information systems (LMIS), poor physical infrastructures in LMICs, lack of trained and dedicated staff for supply chain management, inadequate funding, and rigid government policies on task sharing. However, there is evidence that implementing effective LMISs and involving public and private providers will distribution channels resulted in reduction in medical commodities' stockout rates. Supply chain bottlenecks contribute significantly to persistent high stockout rates for modern contraceptives in LMICs. Interventions aimed at enhancing uptake of contraceptives to reduce the problem of unmet need in LMICs should make strong commitments towards strengthening these countries' health commodities supply chain management systems. Current evidence is limited and additional, and well-designed implementation research on contraception supply chain systems is warranted to gain further understanding and insights on the determinants of supply chain bottlenecks and their impact on stockouts of contraception commodities.

Focusing Conservation Efforts on Ecosystem Service Supply May Increase Vulnerability of Socio-Ecological Systems.

Directory of Open Access Journals (Sweden)

Pedro Laterra

Full Text Available Growing concern about the loss of ecosystem services (ES promotes their spatial representation as a key tool for the internalization of the ES framework into land use policies. Paradoxically, mapping approaches meant to inform policy decisions focus on the magnitude and spatial distribution of the biophysical supply of ES, largely ignoring the social mechanisms by which these services influence human wellbeing. If social mechanisms affecting ES demand, enhancing it or reducing it, are taken more into account, then policies are more effective. By developing and applying a new mapping routine to two distinct socio-ecological systems, we show a strong spatial uncoupling between ES supply and socio-ecological vulnerability to the loss of ES, under scenarios of land use and cover change. Public policies based on ES supply might not only fail at detecting priority conservation areas for the wellbeing of human societies, but may also increase their vulnerability by neglecting areas of currently low, but highly valued ES supply.

The structure of an expert system to diagnose and supply a corrective procedure for nuclear power plant malfunctions

International Nuclear Information System (INIS)

Hajek, B.K.; Stasenko, J.E.; Hashemi, S.; Bhatnagar, R.; Punch, W.F. III; Yamada, N.

1987-01-01

During the past two years, two prototype knowledge based systems have been developed at the Ohio State University. These systems were the result of collaboration between the Nuclear Engineering Program and the Laboratory for Artificial Intelligence Research (LAIR). The first system uses hierarchical classification to diagnose malfunctions of the coolant system in a General Electric Boiling Water Reactor (BWR). The second system provides a plan of action, through a process of dynamic procedure management, to stabilize the plant once an abnormal transient has occurred. The objective of this paper is to discuss the structure that has been designed to integrate the two systems. The combined system will be capable of informing plant personnel about the nature of malfunctions, and of supplying to the operator the most direct corrective procedure available. Two important features of the integrated system are faulty sensor detection, based on malfunction context and unlike sensor data, and procedure management based on the initial state of the plant. Since the two knowledge based systems were developed separately, the integration has required a separate component currently under development, the Plant Status Monitoring System (PSMS). The task of PSMS is to monitor plant parameters in order to detect an abnormal condition developing within the plant. Based on the nature of the event, PSMS is capable of directing control to either the procedure management or diagnosis component. The integrated system plays only an advisory role, and any suggested action would be executed by the plant personnel

Comprehensive evaluation index system of total supply capability in distribution network

Science.gov (United States)

Zhang, Linyao; Wu, Guilian; Yang, Jingyuan; Jia, Shuangrui; Zhang, Wei; Sun, Weiqing

2018-01-01

Aiming at the lack of a comprehensive evaluation of the distribution network, based on the existing distribution network evaluation index system, combined with the basic principles of constructing the evaluation index, put forward a new evaluation index system of distribution network capacity. This paper is mainly based on the total supply capability of the distribution network, combining single index and various factors, into a multi-evaluation index of the distribution network, thus forming a reasonable index system, and various indicators of rational quantification make the evaluation results more intuitive. In order to have a comprehensive judgment of distribution network, this paper uses weights to analyse the importance of each index, verify the rationality of the index system through the example, it is proved that the rationality of the index system, so as to guide the direction of distribution network planning.

Resource use in a low-input organic vegetable food supply system in UK - a case study

DEFF Research Database (Denmark)

Østergård, Hanne; Markussen, Mads V.; Kulak, Michal

2014-01-01

The sustainability of a small-scale low-input organic vegetable farm in United Kingdom with high crop diversity and a related box scheme food supply system was assessed by emergy evaluation, an environmental accounting method based on the direct and indirect use of solar equivalent joules. The main...

The Impact of Implementing a Demand Forecasting System into a Low-Income Country’s Supply Chain

Science.gov (United States)

Mueller, Leslie E.; Haidari, Leila A.; Wateska, Angela R.; Phillips, Roslyn J.; Schmitz, Michelle M.; Connor, Diana L.; Norman, Bryan A.; Brown, Shawn T.; Welling, Joel S.; Lee, Bruce Y.

2016-01-01

OBJECTIVE To evaluate the potential impact and value of applications (e.g., ordering levels, storage capacity, transportation capacity, distribution frequency) of data from demand forecasting systems implemented in a lower-income country’s vaccine supply chain with different levels of population change to urban areas. MATERIALS AND METHODS Using our software, HERMES, we generated a detailed discrete event simulation model of Niger’s entire vaccine supply chain, including every refrigerator, freezer, transport, personnel, vaccine, cost, and location. We represented the introduction of a demand forecasting system to adjust vaccine ordering that could be implemented with increasing delivery frequencies and/or additions of cold chain equipment (storage and/or transportation) across the supply chain during varying degrees of population movement. RESULTS Implementing demand forecasting system with increased storage and transport frequency increased the number of successfully administered vaccine doses and lowered the logistics cost per dose up to 34%. Implementing demand forecasting system without storage/transport increases actually decreased vaccine availability in certain circumstances. DISCUSSION The potential maximum gains of a demand forecasting system may only be realized if the system is implemented to both augment the supply chain cold storage and transportation. Implementation may have some impact but, in certain circumstances, may hurt delivery. Therefore, implementation of demand forecasting systems with additional storage and transport may be the better approach. Significant decreases in the logistics cost per dose with more administered vaccines support investment in these forecasting systems. CONCLUSION Demand forecasting systems have the potential to greatly improve vaccine demand fulfillment, and decrease logistics cost/dose when implemented with storage and transportation increases direct vaccines. Simulation modeling can demonstrate the potential

Direct Current as an Integrating Platform for ZNE Buildings with EVs and Storage: DC Direct Systems – A Bridge to a Low Carbon Future?

Energy Technology Data Exchange (ETDEWEB)

Johnson, Karl [California Inst. for Energy and the Environment, Berkeley, CA (United States); Vossos, Vagelis [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kloss, Margarita [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Robinson, Gerald [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Brown, Rich [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2016-09-01

Cost effective zero net energy (ZNE) schemes exist for many types of residential and commercial buildings. Yet, today’s alternating current (AC) based ZNE designs may be as much as 10% to 20% less efficient, more costly, and more complicated than a design based on direct current (DC) technologies. An increasing number of research organizations and manufacturers are just starting the process of developing products and conducting research and development (R&D) efforts. These early R&D efforts indicate that the use of DC technologies may deliver many energy and non-energy benefits relative to AC-based typologies. DC ZNE schemes may provide for an ideal integrating platform for natively DC-based onsite generation, storage, electric vehicle (EV) charging and end-use loads. Emerging empirical data suggest that DC end-use appliances are more efficient, simpler, more durable, and lower cost. DC technologies appear to provide ratepayers a lower cost pathway to achieve resilient ZNE buildings, and simultaneously yield a plethora of benefits. This paper draws from the current research effort entitled "Direct Current as an Integrating and Enabling Platform," co-led by the Lawrence Berkeley National Laboratory (LBNL), the California Institute for Energy and the Environment (CIEE), the Electric Power Research Institute (EPRI) and funded under the California Energy Commission’s Energy Program Investment Charge (CEC EPIC). The first phase of this EPIC research is focused on assembling and summarizing known global performance information on DC and DC-AC hybrid end-use appliances and power systems. This paper summarizes the information and insights gained from this research effort.

High resolution heat atlases for demand and supply mapping

Directory of Open Access Journals (Sweden)

Bernd Möller

2014-02-01

Full Text Available Significant reductions of heat demand, low-carbon and renewable energy sources, and district heating are key elements in 100% renewable energy systems. Appraisal of district heating along with energy efficient buildings and individual heat supply requires a geographical representation of heat demand, energy efficiency and energy supply. The present paper describes a Heat Atlas built around a spatial database using geographical information systems (GIS. The present atlas allows for per-building calculations of potentials and costs of energy savings, connectivity to existing district heat, and current heat supply and demand. For the entire building mass a conclusive link is established between the built environment and its heat supply. The expansion of district heating; the interconnection of distributed district heating systems; or the question whether to invest in ultra-efficient buildings with individual supply, or in collective heating using renewable energy for heating the current building stock, can be based on improved data.

Hybrid energy system evaluation in water supply system energy production: neural network approach

Energy Technology Data Exchange (ETDEWEB)

Goncalves, Fabio V.; Ramos, Helena M. [Civil Engineering Department, Instituto Superior Tecnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001, Lisbon (Portugal); Reis, Luisa Fernanda R. [Universidade de Sao Paulo, EESC/USP, Departamento de Hidraulica e Saneamento., Avenida do Trabalhador Saocarlense, 400, Sao Carlos-SP (Brazil)

2010-07-01

Water supply systems are large consumers of energy and the use of hybrid systems for green energy production is this new proposal. This work presents a computational model based on neural networks to determine the best configuration of a hybrid system to generate energy in water supply systems. In this study the energy sources to make this hybrid system can be the national power grid, micro-hydro and wind turbines. The artificial neural network is composed of six layers, trained to use data generated by a model of hybrid configuration and an economic simulator - CES. The reason for the development of an advanced model of forecasting based on neural networks is to allow rapid simulation and proper interaction with hydraulic and power model simulator - HPS. The results show that this computational model is useful as advanced decision support system in the design of configurations of hybrid power systems applied to water supply systems, improving the solutions in the development of its global energy efficiency.

Mathematical model for calculation of the heat-hydraulic modes of heating points of heat-supplying systems

Science.gov (United States)

Shalaginova, Z. I.

2016-03-01

The mathematical model and calculation method of the thermal-hydraulic modes of heat points, based on the theory of hydraulic circuits, being developed at the Melentiev Energy Systems Institute are presented. The redundant circuit of the heat point was developed, in which all possible connecting circuits (CC) of the heat engineering equipment and the places of possible installation of control valve were inserted. It allows simulating the operating modes both at central heat points (CHP) and individual heat points (IHP). The configuration of the desired circuit is carried out automatically by removing the unnecessary links. The following circuits connecting the heating systems (HS) are considered: the dependent circuit (direct and through mixing elevator) and independent one (through the heater). The following connecting circuits of the load of hot water supply (HWS) were considered: open CC (direct water pumping from pipelines of heat networks) and a closed CC with connecting the HWS heaters on single-level (serial and parallel) and two-level (sequential and combined) circuits. The following connecting circuits of the ventilation systems (VS) were also considered: dependent circuit and independent one through a common heat exchanger with HS load. In the heat points, water temperature regulators for the hot water supply and ventilation and flow regulators for the heating system, as well as to the inlet as a whole, are possible. According to the accepted decomposition, the model of the heat point is an integral part of the overall heat-hydraulic model of the heat-supplying system having intermediate control stages (CHP and IHP), which allows to consider the operating modes of the heat networks of different levels connected with each other through CHP as well as connected through IHP of consumers with various connecting circuits of local systems of heat consumption: heating, ventilation and hot water supply. The model is implemented in the Angara data

Assessing the quality of energy supplied by small renewable energy systems; Avaliacao da qualidade da energia fornecida por sistemas renovaveis isolados de pequeno porte

Energy Technology Data Exchange (ETDEWEB)

Galhardo, Marcos Andre Barros; Pinho, Joao Tavares [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Grupo de Estudos e Desenvolvimento de Alternativas Energeticas], e-mail: galhardo@ufpa.br, E-mail: jtpinho@ufpa.br

2004-07-01

This paper makes an analysis of the power quality supplied by small renewable energy systems with energy storage in a battery bank and its DC/AC conversion by an inverter. It is shown that the power quality supplied by stand-alone renewable systems depends on the used inverter, specially of its voltage waveform, the load supplied and the voltage level in the battery bank, which has a direct influence on the value of the rms output voltage of the inverter. For these analysis, measurements are presented for typical loads used in these systems as illumination, TV, refrigerator, etc., and combinations of these loads, supplied by different waveforms. (author)

Power supply of ETL-TPE 2

International Nuclear Information System (INIS)

Takeda, Syohei; Sato, Yasuhiro; Kiyama, Satoru; Ikeda, Nagayasu

1986-01-01

The ETL-TPE2 experiment is planned to investigate a behavior of high beta plasma with high temperature. A system design of power supply to generate and to confine the plasma is described. Essential features of the design are the following; 1) To obtain a dense plasma with high temperature, two capacitor banks with opposite polarities of 80 kV charging voltage are provided in tandem feed for the toroidal fast field. 2) A high current pulse with long duration is supplied by a power crowbar system and realizes the investigation of the plasma confinement for a longer pulsed magnetic field. A power supply system of the power crowbar is connected with a main circuit in series through a current transformer. The circuit system is operated at high efficiency and high reliability. 3) In the vertical and compensating field circuits, each rise time and peak value of currents can be controlled over a wide range of pre-set programmings corresponding to an experimental condition. 4) A small resistance is connected with a crowbar circuit in a compression pre-heat field circuit. The circuit can be crowbarred at an arbitrary phase. This operation and the effect of additional resistance are favourable to maintain an effective plasma heating and to improve the plasma confinement. (author)